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Center for Advanced Separation Technologies

     Technology Roadmap




               October 2002
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FOREWORD
In 2000, Virginia Tech and West Virginia University formed a partnership under the umbrella of
the Center for Advanced Separation Technologies (CAST) to conduct fundamental research in
the area of advanced separations. More specifically, the purpose of the partnership was to
create: 1) a knowledge base for solid-solid and solid-liquid separation processes as applied to the
mining industry, and 2) to provide enabling sciences that can permit the economic recovery of the
materials that are being lost as waste or already discarded in waste piles. In view of the
geographic locations of the two universities, the emphasis of their research was on coal, so that
the results of the research would benefit the mining companies located primarily in eastern United
States.

In 2002, five other universities have joined CAST and formed a consortium to conduct
crosscutting advanced separations research that can benefit not only the coal industry but also
the minerals industry across the country. Furthermore, the research activities under CAST would
expand beyond the fundamental research so that near-term interests of the U.S. mining industry
can also be addressed. The new members of the consortium include: Montana Tech, University
of Utah, University of Nevada, New Mexico Tech, and the University of Kentucky.

The consortium brings together multidisciplinary expertise to solve various problems that the U.S.
mining industry is currently facing. The separations research to be conducted at CAST consists
of three broad areas, which include: 1) physical separation, 2) chemical and biological separation,
and 3) environmental control. The research will be carried out in close cooperation with industry.
Although the bulk of the funding comes from the U.S. Department of Energy, cost-shared
industrial participation is encouraged, particularly in the area of near-term research.

During August 14-15, 2002, a workshop was held in Charleston, West Virginia, to identify the
technological needs in the U.S. mining industry, and to prioritize the R&D activities to be
conducted at CAST accordingly. Workshop participants represented a wide range of mining
industry interests. These individuals came from mining companies, equipment suppliers,
government agencies, research laboratories, and universities. The participants included:

Daryoush Allaei                                      Clack Christie
Smart Screen Systems, Inc.                           Consol Energy

Barbara Arnold                                       Asad Davari
PrepTech, Inc.                                       West Virginia University

Richard Bajura                                       Phil Davis
West Virginia University                             Peabody Energy

Peter Bethell                                        John Elder
Massey Energy                                        Outokumpu Technology

Robert Bratton                                       Lucy Esdaile
Virginia Tech                                        Rio Tinto Limited

Corale Brierley                                      Greig Freeman
Brierley Consultancy LLC                             CENfuel FPU LTD.

Kenneth Boras                                        Maurice Fuerstenau
BCS, Incorporated                                    University of Nevada, Reno

William Choate                                       Steve Gamble
BCS, Incorporated                                    IMC Potash Carlsbad, Inc.



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Ari Geertsema                                       James Plumley
Center for Applied Energy Research                  Arch Coal

Kenneth Green                                       Thomas Prater
BCS, Incorporated                                   Teco Coal

Ibrahim Gundiler                                    William Raney
New Mexico Tech                                     West Virginia Coal Association

C. David Henry                                      Laura Richardson
Beard Technology, Inc.                              BCS, Incorporated

Robert Hollis                                       Richard Robinson
Horizon Natural Resources                           Alliance Coal, LLC

Rick Honaker                                        Frank Saus
University of Kentucky                              West Virginia University

John Keating                                        Paul Slater
IMC Phosphates                                      Cytec Industries Inc.

Dennis Kennedy                                      Richard Snoby
Freedom Chemicals                                   Allmineral LLC

Pete Knudsen                                        Richard Sweigard
Montana Tech                                        University of Kentucky

Donald Krastman                                     Michael Taylor
National Energy Technology Laboratory               Hatch Engineering

Jerry Luttrell                                      Richard Terry
Virginia Tech                                       Sedgman

Carl Maronde                                        Roy Tiley
National Energy Technology Laboratory               BCS, Incorporated

Charles Maxwell                                     Philip Thompson
Phelps Dodge Mining Co.                             Dawson Metallurgical Labs

JD Miller                                           Tom Toscano
University of Utah                                  CyTec Industries

Robert Moorhead                                     Marc Villegas
Krebs Engineering                                   BCS, Incorporated

Charles Murphy                                      Dan Yanchak
Riverton Coal                                       Consol Energy

Richard Noceti                                      Roe-Hoan Yoon
National Energy Technology Laboratory               Virginia Tech

Felicia Peng                                        Joe Zachwieja
West Virginia University                            Akzo Nobe

Dennis Phillips                                     Contact information for these participants is
The Daniels Co.                                     provided in Appendix A of this report.



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TABLE OF CONTENTS

Foreword                                                            i

Introduction                                                        1

Physical Separations                                                3

Chemical and Biological Separations                                 17

Environmental Controls                                              28

Conclusion                                                          37


Appendices

A. List of Participants                                             A-1

B. Terms and Definitions                                            B-1

C. CAST Organization Chart                                          C-1


Exhibits

1. CAST Research Areas                                              2

2. Physical Separation Challenges                                   4

3. Size-Size Separation Research                                    7

4. Solid-Solid Separation Research                                  13

5. Solid-Liquid Separation Research                                 16

6. Chemical and Biological Separation Challenges                    18

7. Chemical and Biological Leaching Research                        21

8. Concentration and Purification Research                          23

9. Product Recovery Research                                        25

10. Crosscutting Research for Chemical and Biological Separations   27

11. Environmental Control Challenges                                29

12. Emissions Control Research                                      31

13. Remining Research                                               33

14. Waste Disposal Research                                         36




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INTRODUCTION

The U.S. is the largest mining country in the world. In 2001, the mining industry produced $57.3
billion of raw materials, which consisted of $39.0 billion from minerals and $19.0 billion from coal.
The mineral processing industries increased the value of the minerals to $374 billion, while coal
and uranium were used to produce $147 billion of electricity. Thus, the minerals and coal
industries together contributed $521 billion to the nation’s wealth, which accounted for
approximately 5.2% of the Gross National Product of 2001.

According to the Annual Energy Outlook 2002, the U.S. generated 1,968 billion kWh of electricity
from coal and 626 billion kWh from natural gas in 2000. The average fuel costs were $1.20 per
million Btu for coal and $4.30 per million Btu for natural gas. Despite the higher price, about 90%
of all new electricity plants currently under construction will be fueled by natural gas. The main
reasons for favoring natural gas are low capital costs, higher efficiency, and lower emissions.

One of the problems the coal industry is facing today is the environmental concerns created
during coal production. On October 11, 2000, a 72-acre coal waste impoundment near Inez,
Kentucky, accidentally released 250 million gallons of slurry into nearby underground mines,
creeks, rivers, and schoolyards. This incident caused the U.S. Congress to appropriate $2 million
for the National Research Council (NRC) to investigate the case and study the ways of reducing
the potential for future incidents. According to the NRC report, U.S. coal industry discards 70-90
million tons of fine coal annually to 713 active impoundments, most of which are located in
Central Appalachia. Over the years, approximately 2.5 billion tons of fine coal has been
discarded in impoundments. The report also stressed the need for additional research to develop
technologies that can be used to eliminate the fine coal impoundments in the U.S.

Fine coal impoundments are just one indicator that there is a lack of appropriate technologies for
processing fine coal. In 1998, the National Mining Association (NMA) developed a roadmap for
the research needs of the U.S. mining industry. It states, “advances in mineral (and coal)
processing technology have leveled off, making radical technological breakthroughs necessary
for significant advances.” The various processes used for upgrading coal and minerals can be
divided into physical separation, chemical/biological separation, and environmental control
processes. The roadmap developed by NMA was for the U.S. Department of Energy, Mining
Industry of the Future Program which is designed for improving energy efficiency in the mining
industry rather than increasing the efficiency of raw materials production in environmentally
acceptable manner.

In May 2001, the National Energy Policy Development Group, chaired by Vice President Cheney,
produced the National Energy Policy white paper outlining President Bush’s supply side energy
policy. According to the white paper, the President’s goal in formulating the Nation’s energy plan
is to ensure a steady supply of affordable energy in environmentally responsible and sustainable
manner. The Clean Coal Power Initiative started in 2001 is part of this new policy. This new
initiative is designed mainly to burn coal cleanly and efficiently. To address the technological
needs for producing coal, the Fossil Energy Research Program, U.S. Department of Energy,
initiated the Advanced Separation Program to develop technologies that can be used for
producing clean coal in environmentally acceptable manner.

In 2000, Virginia Tech and West Virginia University established the Center for Advanced
Separation Technologies (CAST) under the auspices of the U.S. Department of Energy, National
Energy Technology Center, through a competitive solicitation (DE -PS26-00FT40756) process.
The objective of the Center was to create a knowledge base that can lead to the development of
solid-solid and solid-liquid separation processes that can be used by the U.S. mining industry,
and to provide enabling sciences that can permit the economic recovery of the materials that
have been discarded to waste piles and impoundments.



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                                    e
In 2002, CAST signed a Cooperativ Agreement with NETL to expand its research activities
beyond the realm of fundamental research on coal. The CAST still emphasizes longer-term,
high-risk research in coal. However, development of crosscutting technologies that can be used
for coal cleaning, mineral processing, and environmental control with objectives of near-term
applications will also be addressed. In order to implement this new approach, CAST membership
has been extended to five other universities, which included New Mexico Tech, University of
Nevada-Reno, Montana Tech, University of Kentucky, and University of Utah.

Recently, NRC evaluated the performance of DOE’s R&D programs during the period of 1978-
2000. The report recommended DOE to “support coal preparation technology development in
academia, which helps to train technical people for the industry”. In another NRC report, it was
suggested, “Consortia are a preferred way of leveraging expertise and technical inputs to the
mining sector, and the consortia approach should be applied wherever appropriate”. It also
stated that “Consortia should include universities, suppliers, national laboratories, and any ad hoc
groups considered helpful, government entities, and the mining industry”. The proposed CAST
program is consistent with these recommendations, and meets the objectives specified in the
Request for Proposals (RFP) and those of the Advanced Fuels Program in general.

During August 14-15, 2002, CAST hosted a workshop in Charleston, West Virginia, to develop a
roadmap for research. The workshop was attended by industry leaders, who presented their
views on technological needs for the U.S. mining industry. The participants were divided into
three sessions: 1) Physical Separation, 2) Chemical/Biological Separation, and 3) Environmental
Control. Each session was facilitated and monitored by personnel from BCS, Incorporated, which
had previous experience in developing roadmaps. BCS, Incorporated drafted the results of the
workshop and distributed it to the participants to review and finalize. Exhibit 1 shows a matrix of
the items discussed at the workshop. Appendix 1 gives definitions of the items of the matrix.



                             Exhibit 1. CAST Research Areas

    Physical                          Chemical                           Environmental
   Separations                       Separations                            Control


               Size-Size                           Leaching                            Emission
              Separations                                                               Control


                                                       Solution
              Solid-Solid                                                              Remining
                                                     Concentration
              Separations
                                                   and/or Purification


              Solid-Liquid                          Product                               Waste
              Separations                          Recovery                              Disposal




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PHYSICAL SEPARATIONS
Physical separations are those processes in which valued substances (minerals and coal) are
separated from undesired substances, based on the physical and physiochemical properties of
the materials involved. The physical properties include particle size, specific gravity, electrical
conductivity, magnetic susceptibility, optical properties, while physiochemical properties include
hydrophobicity, surface charge, and acid-base properties which in turn vary with operating
variable. One of the most important factors affecting various physical separation processes is
particle size, and each process has a range of particle sizes in which it is most effective.
Generally, separation efficiencies decrease as the size of the particle decreases. The various
unit operations involved in physical separations include:

•   Size-Size Separations
    o Screening
    o Classification

•   Solid-Solid Separations
    o Flotation
    o Selective Flocculation
    o Magnetic/electrostatic Separation
    o Gravity Separation

•   Solid-Liquid Separations
    o Thickening
    o Centrifugation
    o Filtration
    o Drying

Each of the terms listed above is defined in Appendix B, and Exhibit 2 lists the technological
needs and challenges identified at the Workshop held in Charleston, West Virginia on August 15,
2002. Overall, exploring different mining and beneficiation technologies to improve industry
productivity is an important need that crosscuts the size-size separations, solid-solid separations,
and solid-liquid separations technologies. There is also the need to educate the public of the
important role coal plays in meeting national energy needs.




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                                           Exhibit 2. Physical Separations Challenges

Size-Size                                  Solid-Solid                                                         Solid-Liquid

General                                    General                                                             General

• More efficient sizing                    • Address environmental concerns                                     • Increased moisture removal at a lower
                                           • Improve selectivity                                                   cost
• Reduce energy required by size
                                           Flotation                                                           Thickening
Screening
                                           • Improve process control for flotation                             • Further development and implementation of
• Improve efficiency and throughput,       • Improved understanding of the effect of the quality of process      paste thickening methods to eliminate
  while at the same time increasing          water on flotation                                                  impoundments
  the wear life of screens                 • Improved handling of column flotation products, which are         • Study flocculation of clay to increase its
• De-sliming spiral concentrates to          difficult to pump due to frothing problems                          settling rate and achieve higher % solids
  remove high-ash clay slimes from         • Improved understanding of the mechanisms involved in column       • Improve space utilization by decreasing foot
  products                                   flotation                                                           prints; increase capacity per unit area
• Efficient sizing at ultrafine particle   • Develop reagents to float coarse particles                        • Develop alternative chemistries to improve
  sizes, e.g., 150 µm or less; need        • Develop a single collector for phosphate-sand separation            thickening
  to develop more efficient equipment      • Develop efficient reagent system for dolomite-phosphate           • Improve the kinetics of fine particle
• Fine coal screening and desliming          separation                                                          thickening and reduce costs
• Noise reduction to improve worker        • Develop reagents for more efficient separation of minerals and    • Increase the % solids of thickener underflow
  health                                     coal                                                                for ready disposal
• Reduce maintenance costs and
  energy consumption                       Selective Flocculation                                              Centrifugation
• Minimize blinding problems to
  improve productivity, save energy,       • Recovery of phosphate from cyclone overflows                      • Study the impact of the -325 mesh fraction
  and reduce costs                         • Improved recovery of kaolin with maximum recovery                   in the screenbowl centrifuge feeds.
                                           • Develop more flocculants for selective flocculation               • Develop methods of improving the fines
Classification                                                                                                   recovery during screenbowl centrifuging

• Efficient desliming at 100 and 325
                                           Magnetic/Electrostatic Separation
                                                                                                               Filtration
  mesh                                     •   Field flow fractionation
• Ultrafine sizing/desliming                                                                                   • Improve belt press that is widely used for
                                           •   More efficient electrostatic separators and circuits
• Centrifugation: lower                                                                                          dewatering fine reuse. The improvement
                                           •   Fine electrostatic separation below 75 µm
  moisture/improved recovery                                                                                     can reduce flocculant dosage and increase
• Classification at 400 mesh               •   Improved magnetite recovery from coal cleaning circuits
                                                                                                                 throughput.
• Ultrasonic enhancement                                                                                       • Ultra fine coal filtration
• Screening clays                          Gravity Separation
                                                                                                               • Improve filtration efficiency by emphasizing
• Improving classification with                                                                                  studies on the basic mechanisms
  efficiency                               • Move the separation process closer to the “face”
                                                                                                               • New ways to reduce moisture of fine coal to
• Alternatives to cyclones to minimize     • Improve spirals to achieve lower S.G. cut points
                                                                                                                 less than 8 percent
  circulating load (or to minimize         • Expand the size range treated
  misplacement of ground material)         • Improve the separation efficiency of spirals
                                           • Improve efficiencies at 1 mm x 250 µm sizes at controllable
                                                                                                               Drying
• Minimize fine particles reporting to
  classifier underflow                       D50’s between 1.45-1.60 SG
                                                                                                               • Briquetting of fines
• Effective removal of slimes without      • Comparison of fine (1mm x 100 µm) coal cleaning technology
                                                                                                               • Develop/improve small-scale thermal driers
  loss of phosphate grade                  • Enhancement of the ability to achieve efficient density
                                                                                                                 for ultra fine coal to improve energy
                                             separations for fine and ultrafine particles                        efficiency
Automation/                                                                                                    • Packaged coal-fired units
Controls/Sensors                           Optical Sorting                                                     • Drying slurry gob fines (0.5mm or less) to
                                                                                                                 moistures as low as one percent
                                           • Improve/develop optical sorting technologies                      • Drying of ultra fine coal
• Develop and improve sensors and
                                           • Develop new sensors                                               • Develop/improve chemical additives,
  controls to improve efficiency and
  productivity                                                                                                   mechanical methods, and thermal methods
                                           Automation/Controls/Sensors                                           including the method of using microwaves

                                           • Develop on-line analysis system that is affordable and requires   Automation/Controls/
                                             low maintenance costs                                             Sensors

                                                                                                               • Develop on-line analysis system that is
                                                                                                                 affordable and low maintenance




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Size-Size Separations
Size-size separations are often practiced prior to solid-solid separations because a given solid-
solid separation method is effective only within a range of particle sizes. Thus, efficient size-size
separations can result in efficient solid-solid separations.

There are many technical challenges in size-size separation. Generally, there are too many
processing steps involved between the feed and the final product that add to inefficiencies. On
the other hand, if a by-zero feed could be processed directly to a final product, there would be no
need for size-size separation steps. Until efficient solid-solid separation processes are
developed, there is a mid-term R&D need to develop devices capable of separating particles to
different sizes. Also there is a need to develop physical separation systems with integrated
intelligence both at software and hardware levels. More efficient motors (or shakers) are also
needed that are more advanced over the simple eccentric motors currently used in the industry.
The smart material technology has reached a level of development that smart motors and
miniaturized motors are possible.

The challenges and strategies for size-size separations are discussed below:

Screening

Screening is used to separate relatively coarse particles according to their sizes. Fine screens
are fragile, wear quickly, are easily blinded, and suffer from low throughput and low efficiency.
Therefore, screening is limited in general to materials coarser than approximately 250 µm. On
the other hand, screening is more efficient than classification. Thus, there is a need to develop
methods of screening finer particles.

There are several important aspects in fine screening, namely, capacity, wear, and blinding.
Fundamentally new concepts may be needed to develop screens with high capacity, minimum
wear, and blinding problems. In many areas, vibration-based screens blind about 50% of the
screen panels in a short period after put in operations (as early as 24 hrs). This should be
reduced in order to help the industry to significantly reduce cost and energy consumption. If an
efficient fine screening method becomes available, it can be used for removing fines from the
feeds to various solid-solid and solid-liquid separation processes, which will result in increased
efficiency.

For screening coarse particles, there is a need to improve the design of the screens used in
industry today to increase the capacity, decrease noise, minimize maintenance costs, and reduce
energy consumption. For example, noise and vibrations should be reduced by 10 to 30 dBA
(noise) and 10 to 20 dB (Vibrations). Many of the current vibrating machines have noise level
about 90 to 115 dBA. When several of these machines are put in one plant, the noise level is
even higher. The bearings on these machines become noisy even before the bearing stop
functioning, and the noise level can be as high as 120 to 130 dBA. This kind of environment
affect worker performance and fatigue. Future machines should have noise level below 70 dBA.
There is also a need to conduct research to improve the performance of banana screens, which
are becoming popular in the mining industry due to their high capacity.

Finally, there is a need to develop mathematical models for screening that will be useful for
designing and selecting appropriate screens for various applications.

Classification

In classification, particulate materials are separated according to the velocities of the particles
moving in a fluid, usually in water or air. Wet-classification is typically more efficient than air
classification. Efficiency of classification depends not only on particle size but also on specific



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gravity (S.G.) and shape. In general, classifiers are less efficient than screens but are capable of
higher capacity.

Within the area of classification, there is a need to improve the efficiency of size-size separation
at 100, 325, and 400 mesh. Availability of efficient classifiers should increase the efficiency of
solid-solid and solid-liquid separations.

E vaporite minerals typically have swelling bentonite clays associated with the ore. The clay must
be dispersed and separated from the salts. As the clay is dispersed, the viscosity of the transport
brine further increases and decreases the separation efficiency of the hydrocylcone. This results
in sending fine sized product to waste along with the clays in the cyclone overflow. Developing
alternatives to hydrocyclones or improving existing technologies should minimize circulating load
to grinding mills. In the near-term, studies on the fundamentals of classification should be
conducted. Application of computational fluid dynamics to hydrocyclones should lead to an
improvement in existing cyclone and to the development of entirely new designs. Application of
ultrasonic technologies may prove useful in increasing the efficiency in hydrocyclones. Studies on
cyclone circuit analysis should also be conducted.

In hydraulic classification, coarse particles settle at the bottom and are discharged, while fine
particles stay in suspension and overflow into a launder. A problem here is that significant
amount of the fines are misplaced to the coarse fraction by entrainment. There is a need to
minimize this problem through further research.

While hydraulic classification may be useful for sizing relatively coarse particles, they cannot be
used for separating fine particles under gravitational field. High-G centrifuges are used in the
kaolin clay industry. It may be useful to modify the centrifuges for use in the coal and other
mineral industries.

In the mid-term, developing efficient dry sizing methods will be important in many different
segments of the U.S. mining industry.

Automation, Controls, and Sensors

There is a need to develop and improve automation, control, and sensor technologies used in
size-size separation processes. Improved measurement systems and operator-independent
controls could improve efficiency and productivity for the industry. Various sensors are used for
particle size analysis in laboratories. However, they are not widely used for on-line particle size
analysis in industry. It will be useful, therefore, to further develop appropriate on-line sensors to
determine the efficiency of hydrocyclones and hydraulic classifiers. Availability of such sensors
will allow the entire circuit, consisting of classifiers and solid-solid or solid-liquid separators, to be
optimized.

Exhibit 3 shows areas for R&D emphasis. Through R&D, significant improvements in size-size
separation can be realized in the near-term (0-3 years), mid-term (4-10 years), and the long-term
(11+ years).




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                           Exhibit 3. Size-Size Separations Research

    Area                  Near-Term                         Mid-Term                        Long-Term
                          (0-3 years)                       (4-10 years)                    (11+ years)


    General                  Study and develop a device capable of effectively cleaning
                                                500 µm x 0 sizes

                                Develop more efficient, smart, and miniature motors
                                                         (1)

                                                                      Develop physical separation systems with
                                                                  integrated intelligence in software and hardware
                                                                                          (1)


                                 Design efficient               Reduce noise vibration          Reduce noise level
    Screening             classifying/sizing separation        by 10-30 dBA (noise) and           below 70 dBA
                            system to separate finer             10-20 dB (vibration)                  (1)
                                    particles                             (1)
                                       (6)

                          Perform application research
                            on banana screening to
                              improve screening of
                                coarse materials
                                      (4)

                            Screening (Fine): Study                Reduce blinding in
                          mechanism of blinding in 250             screening by 20%.
                           µm separations to improve                      (1)
                           screening of fine materials
                                      (2)

                          Develop mathematical models
                            for screening to pre -select
                          appropriate screens for various
                                    applications
                                        (1)


    Classification         Improve efficiency of size-          Techniques, equipment,
                           size separation at 100, 325,             and application
                                   400 mesh                          for dry sizing
                                       (4)                                 (3)

                          Studies on the fundamentals
                           on classification including
                                    cyclones
                                       (1)


    Automation/               Develop on-line, unit device control, performance control
    Controls/
    Sensors
Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.




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Solid-Solid Separations
In solid-solid separations, one type of particulate material is separated from another for value
enhancement, or to meet environmental requirements. This separation is affected by exploiting
differences in specific gravity, magnetic susceptibility, electrical conductivity, surface property,
and dielectric property.

Methods used in solid-solid separations include flotation, selective flocculation, gravity separation,
magnetic/electrostatic separation, and optical sorting.

There are many technical challenges for the mining industry that directly relate to solid-solid
separations. Generally, there is a need to improve the separation efficiencies over a wide range
of particle sizes with minimum energy requirement. Specific challenges in different areas of solid-
solid separations are discussed below.

Flotation

Flotation is a method by which particulate materials dispersed in water flow through a tank, into
which air bubbles are introduced. The air bubbles selectively collect the particles that are
hydrophobic and exit the tank by levitation while leaving hydrophilic particles behind. Thus, the
separation is based on rendering a selected material hydrophobic, although some are naturally
hydrophobic. Various reagents are used to hydrophobize different materials. In general, flotation
is effective in the particle size range of approximately 10 to 100 µm for minerals and 44 to 500 µm
for coal. It experiences difficulties with coarse and ultra fine particles.

In most of the mineral and coal processing plants operating in the United States, spent process
water is recycled. This creates enrichment of chemicals and the elements (e.g., heavy metals)
derived from the minerals and coal in the process water. The heavy metals, as an example, can
activate unwanted minerals and, thereby, cause deleterious effects on selectivity.

Column flotation is useful for producing final concentrates in a single stage. To achieve this, it is
necessary for the columns to operate at high surface area rates (S b), which can be achieved by
decreasing bubble size (Db ) using stronger frothers. However, use of excessively strong frothers
can cause froth-handling problems downstream. It is, therefore, necessary to develop frothers
that can produce small bubbles without causing the froth-handling problem. An alternative may
be to develop advanced bubble generation methods that can produce small air bubbles using
weaker frothers.

The U.S. phosphate industry is experiencing difficulty with depleting high-grade ore reserves and
stiff foreign competitions. To combat this situation, it is necessary to develop new, revolutionary
processing technologies. At present, the industry is using anionic flotation, followed by acid
treatment and cationic flotation. It would be beneficial to use a flotation system that can
beneficiate phosphate ores with a single efficient collector. For this to be possible, the collector
should be highly selective against gangue minerals such as calcite and silica. Also, it is desirable
to develop a collector that is powerful enough to float coarse particles of phosphate, which
account for the major loss in current operation.

At present, approximately 30% of the phosphate mined in Florida is lost in the fines fraction that is
removed using hydrocyclones prior to flotation. The desliming is necessary because the flotation
processes that are currently employed in industry are inefficient with fine particles. Therefore, it
would make a significant impact on the industry if efficient methods of recovering the phosphate
fines were developed. A high priority in the near-term is the development of better flotation
systems for phosphates. This would include more selective flotation reagents, efficient flotation
circuits, on-line process control system, and efficient flotation machines.




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The U.S. kaolin industry is facing similar problems as the phosphate industry, with declining high-
grade reserves and increasing competitions from Brazilian kaolin and precipitated calcium
carbonate (PCC). The major discoloring impurities in kaolin clay are anatase (TiO2 ) and iron
oxides (Fe2O3 ). The former is substantially removed by flotation with high recoveries, while the
latter is removed by leaching in acidic media under reducing conditions. Flotation is efficient in
removing anatase from the coarse clay mined in middle Georgia, but faces difficulty with the fine
clay mined in east Georgia. It would, therefore, be beneficial to the U.S. clay industry to develop
methods of beneficiating the east Georgia clay by flotation. It would also be of interest to further
develop the flotation process to remove mica and smectite, which are the major culprits for the
high viscosity problems associated with handling highly-loaded kaolin clay suspensions.

In the kaolin industry, iron oxides are removed by sulfuric acid. It would be of interest to develop
methods of leaching the impurities in neutral media, or developing more effective leaching
agents. This will allow the industry to mine low-grade kaolin containing high iron contents.

High-grade kaolin concentrates are shipped to paper companies in slurry form at 70% solids or
higher. To increase the stability at high percent solids, dispersants (e.g., polyacrylates) are used.
It will be of interest to develop dispersants that can increase the stability at higher percent solids.

Flotation is a rate process; therefore, it would be of fundamental importance to study the
mechanisms involved in flotation kinetics, including comprehensive model development.
Flotation is complex, involving three phases (i.e., solid, liquid, and air). Therefore, developing a
comprehensive model is a challenge. Nevertheless, progress has been made in recent years in
developing models based on first principles. A successful model can be used to predict methods
of improving flotation, both by control of hydrodynamic and surface chemistry conditions. The
hydrodynamic conditions can be modified by bubble-size, energy dissipation, etc., while the
surface chemistry conditions can be controlled by using appropriate reagents. The
comprehensive flotation model can be used to develop simulators that can be used to optimize
industrial flotation processes. The model can also be used for on-line control purposes, for which
sensor development is essential. Some of the sensors needed for control purpose include those
that can measure bubble size distribution both in the pulp and froth phases, bias rate, bubble
carrying capacity, and velocity of particles and bubbles. Laser Doppler velocimeters and video
cameras may be useful for obtaining information on hydrodynamics information during flotation.
Sensors for various chemicals present in flotation pulp will also provide vital information for
optimizing flotation based on kinetic models.

Selective Flocculation

Ultra fine particles are dispersed in water with the aid of peptizing agents. An organic flocculant
or coagulant is then added to enlarge the size of the selected constituent so it can settle to the
bottom of a settling vessel, while others are left in suspension. Thus, the separation is based on
causing a flocculant or coagulant to selectively adsorb on the surface of a selected particulate
material. The selective flocculation process is practiced in the U.S. kaolin industry for the
removal of anatase from kaolin clay. Several companies developed their own selective
flocculation processes using different chemistries. The process is efficient with the east Georgia
clay which is too fine to be beneficiated effectively by flotation. Although selective flocculation is
effective for the beneficiation of ultra fine particles, it suffers from low recovery due to entrapment
of unwanted particles in the settled zone. Therefore, there is a need to develop methods of
increasing the recovery. Selective flocculation may also be used to beneficiate the phosphate
fines that are currently being discarded in the phosphate industry.

Magnetic/Electrostatic Separation

Magnetic separation is a method in which magnetic particles are separated from non-magnetic
particles in a magnetic field. Its efficiency decreases with decreasing magnetic susceptibility and
particle size although cryogenic high-intensity and high-gradient magnetic separators can



                                                 9
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                                       October 28, 2002

overcome these problems. Electrostatic separators are designed to separate charged particles in
an electrical field. Particles can be charged by induction, conduction, or triboelectrification
mechanism.

Various magnetic separators are used to separate ferromagnetic and paramagnetic materials
from diamagnetic materials. In the kaolin industry, high-gradient-magnetic separators (HGMS)
are used to separate anatase and iron oxides from kaolin. This technology was developed during
the early 1970s. Although significant progress has been made since then, the process had
difficulty in separating ultrafine particles. Further development of the technology is needed to
process lower-grade kaolin.

Magnetic separators are used extensively in coal industry for the recovery of magnetite.
Improving the magnetite recovery through development of more efficient magnetic separators or
through changes in processing circuitry would help the coal industry minimize its operating costs.

Electrostatic separators are used to separate conducting and non-conducting particles. In
general, they are useful for separating particles of relatively narrow size distributions, and are
inefficient with particles below 74 µm. On the other hand, there is a need for electrostatic
separators that can be used for separating fine particles. An inherent advantage of electrostatic
separation is that it is a dry process, which obviates the need to dewater the products.

A mid-term strategy that would improve magnetic/electrostatic separations includes studying the
mechanisms of separating fine-particles (-75 µm) by electrostatic separation, and developing
efficient methods of cleaning electrodes.

Gravity Separation

Gravity concentration processes are used to separate particles based on differences in density
(or specific gravity). This technique currently serves as the primary method for upgrading iron
and tungsten ores, and is used extensively to upgrade coal, tin, and industrial minerals. The
performance of gravity concentrators is influenced by a variety of factors including particle
properties (size, shape, and density), fluid rheology, and equipment characteristics. Careful
control of particle size is particularly important since a single gravity separation process that is
currently available commercially cannot effectively treat feed streams consisting of a wide-range
of particle size distribution. In general, fine particles do not respond well to gravity separation
since gravitation forces diminish relative to viscous fluid forces as particle size is reduced. In
such cases, centrifugal forces may be used to increase the settling rates of fine particles and,
thereby, enhance the separation.

Many U.S. mining companies would benefit from advancements in gravity concentration
processes. In the eastern United States, a variety of gravity separators are used to remove
inorganic rocks from carbonaceous matter (coal). Dense-medium processes, such as baths and
cyclones, are widely used to separate coarser (>1 mm) particles with high efficiency. These
separators have become standards in all of the new (or newly renovated) plants. Although
revolutionary improvements in the design of dense-medium separators may not be required, their
efficiencies can be increased substantially by improving on-line instrumentation and control.
Also, there is a need to improve the wear resistance of the materials used for the various dense-
medium separators. It is believed that these improvements are possible in the near- to mid-term.
Also, there is a need to find alternative sources of affordable dense media (e.g., fine magnetite) in
view of the recent changes in market supplies. Methods of recovering magnetite from waste
streams and minimizing its losses in various stages would help coal companies to cope with the
dwindling supply of magnetite.

While dense-medium separators process coarse particles efficiently, the gravity separators for
small (1 x 0.15 mm) and fine (<0.15 mm) particles are inefficient. Therefore, there is a need to
develop breakthrough technologies for the gravity separation of fine particles. Some of the



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common water-based processes that are currently used to treat small (1 x 0.15 mm) particles
include large-diameter spirals, water-only cyclones, shaking tables, and teeter-bed separators.
However, the use of these separators entails misplacement of coal and rock particles, which is
often amended by implementing multi-stage cleaning operation.

Selection of one separator over another is often based on equipment costs and operator
preferences without due consideration of technical merits. To minimize the operator bias, it is
necessary to compare different gravity separators (and circuit configurations) in the near-term.
The results will be useful to provide proper design information, scale-up criteria, operating
procedures, and application guidelines.

In the near- to mid-term, it is necessary to develop alternative gravity separators that can achieve
higher throughput, improved separation efficiencies, lower-density cut-points (i.e., cleaner coal),
finer particle size cutoff, as well as lower operating and maintenance costs. Development of
advanced sensors and automation systems that can improve the monitoring and control of these
processes is also needed in the mid-term. To improve the separation of fine particles (<0.15
mm), a high priority should be given on developing advanced enhanced-gravity separators using
high-G forces with the objective of near-term application. Advances in the enhanced-gravity
separation would have crosscutting applications in coal, minerals and environmental industries.

There is an incentive to move part of the gravity separation processes used for cleaning coal
closer to the working face of a mine. If this concept, which is referred to as deshaling, can be
implemented successfully, coal companies can minimize transportation and disposal costs for
unwanted waste rocks. Some of the processes that can be used for deshaling include pneumatic
jigs and low profile screen/jig combinations. Electronic ore sorters, which utilize sensors to detect
differences in particle density, may also be used. Deshaling may be extended even to the mining
phase through the use of advanced sensors that can detect and avoid the extraction of the waste
rocks during the mining operation. The development of efficient deshaling processes that can
avoid the use of water as a separating medium would be of particular interest in view of the high
costs associated with dewatering. Successful deployment of the deshaling concept should
increase both industry productivity and energy efficiency.

Finally, the strategies for improving the various gravity separation processes should also include
fundamental studies, which is conducive for developing revolutionary technologies. In the near-
term, improved phenomenological models need to be developed for a variety of gravity
concentration processes such as dense-medium baths and cyclones, water-only cyclones, coal
spirals, teeter-bed separators, and enhanced-gravity separators. In the near- to mid-term, studies
on fluid flow, hydrodynamics, and computational fluid mechanics will be useful.

Optical Sorting

Optical sorters are used for separating particles that are liberated at relatively large sizes (>10
mm). They are used for separating diamond, gold, uranium, and sulfide ores. They are also
used for separating plastic bottles in the recycling industry. The optical sorters are equipped with
appropriate sensors (e.g., x-ray, infrared, and γ-rays) to detect different particles. The information
from the sensors is fed to microprocessors that are designed to make decisions whether or not to
reject the particles from a moving stream. Such devices are useful for pre-concentration, which
can increase the throughput and result in energy savings. Further development in sensors and
finding new applications in the U.S. minerals and coal industry will be of value.

Automation, Controls, and Sensors

Improving automation, control, and sensor technologies is a key challenge for the industry to
overcome. Not only would automating physical separation processes increase the efficiency of
solid-solid separations, but it will also benefit employee’s safety and health. Improved on-line
analysis systems need to be affordable, low maintenance, and user friendly. A high-priority



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                                     October 28, 2002

strategy that would improve the productivity of the industry in the mid-term includes developing
on-line washability, on-line performance measurement and partition data, and spiral performance
control. The development of unit or device control systems and on-line particle size analysis is
needed.

Exhibit 4 shows the areas for R&D emphasis for size-size separations. The research is
organized by near-term (0-3 years), mid-term (4-10 years), and long-term (11+ years).




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                                      October 28, 2002
                         Exhibit 4. Solid-Solid Separations Research

    Area                       Near-Term                        Mid-Term                           Long-Term
                               (0-3 years)                      (4-10 years)                       (11+ years)

                                Floatation systems for                   Flotation of soluble salts, in particular, the
   Flotation                   phosphates, potash ores,                  development of flotation strategies for the
                                      and kaolin                                  processing of trona ores

                                Evaluate flotation kinetics
                                  and hydrodynamics

                                  Use of microbubbles/
                                picobubblesl to eliminate
                                froth-handling problems



   Selective Flocculation          Develop methods of
                                increasing the recovery of
                                          clays



   Magnetic/Electrostatic       Further develop HGMS to
                                process lower-grade kaolin
   Separation
                               Increase fine recovery from
                                 electrostatic separators


                                Studies on separating fine
                                particles with electrostatic
                                        separators


                                  Develop more efficient magnetic separators to increase
                                                 recovery of magnetite


   Gravity Separation             Improve efficiencies of
                                dense-medium separators


                                 Develop alternatives for
                                 affordable dense media


                                 Fundamental studies to             Develop gravity separation
                                compare different gravity            processes closer to the
                                      separators                          working face


                                                                                 Breakthrough technologies in
                                                                               gravity separation of fine particles



   Optical Sorting                                  Develop and find new applications for optical sensors



   Automation/                                                    On-line washability; on-line              On-line mineral
                               Fundamental surface
                                                                  performance measurement;                    liberation
   Controls/Sensors            chemistry for in-situ
                                                                spiral performance control; unit
                                spectroscopy and
                                                                       or device control of
                                 interaction force
                                                                 performance; on-line particle
                                  measurements
                                                                           size analysis
                                                                                (9)


Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.




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                                       October 28, 2002
Solid-Liquid Separations
In the mining industry, most solid-solid separations occur in water. The products are dewatered
to minimize shipping costs, improve handling, and increase market values. The solid-liquid
separation processes used in the minerals and coal industries include thickening, centrifugation,
filtration, and drying.

There are many technical challenges for the separations industry that directly relate to solid-liquid
separations, as discussed below:

Thickening

Thickening is a method by which particulate materials are allowed to settle by gravity in a large
settling tank. The supernatant water overflows into a launder, while the thickened slurry is
removed at the bottom. Lamella thickeners are used to decrease settling distances and increase
settling area, thereby decreasing the equipment size. Paste thickeners are designed to produce
high percent solid underflows. To increase settling rates, particle sizes are enlarged by adding
various flocculants and coagulants.

Gravity thickeners take large areas and large capital to install. Lack of overflow clarity and low
underflow density lowers the plant product recovery in the evaporite mineral industry. Increasing
the capacity per unit area of a thickener is a primary interest to industry. This may be achieved
by improving the chemical additives, optimizing the mode of reagent addition, or improving
thickener design.

More recently, interest has been shown in increasing the percent solids of thickener underflows
so that they can be stacked up rather than being disposed of in impoundments. This is partly
because of the recent failures in coal refuse impoundment in Appalachian coalfields. Paste
thickening is known to produce densified underflows. Further studies in this area, and utilization
of the new technology to eliminate fine coal impoundments, will be of great value to the coal
industry in the near term. The technology will also be useful for managing the clay tailings
generated in the phosphate industry.

A near-term, high-priority research area is to improve thickener designs with objectives of
increasing settling rates and increasing percent solids in the underflows. Future research should
also include fundamental studies on the effect of surface chemistry and water chemistry on
settling rate. Electro-coagulation may also shed light to improving thickening. There is a need for
improved thickener designs and better chemicals that can be used to meet the objectives of both
mineral and coal industries.

Centrifugation

In centrifugation, high-G forces are used to greatly increase the settling rates and to obtain higher
percent solid materials. Solid bowl and screen bowl centrifuges are widely used in industry. The
latter produces lower moisture products than the former by virtue of the loss of finer particles.
Owing to their higher settling rates, centrifugal dewatering devices have high throughput.

Over the years, screen bowl centrifuges have replaced vacuum filters in the U.S. coal industry.
The main reason for this is that the former can produce lower moistures than the latter. However,
screen bowl centrifuges lose significant amounts of fine coal as effluent, which is a concern to
many coal producers. Therefore, there is a need to find ways to improve coal recovery, while
maintaining low moistures.

There is also a need to study the effect of the -325 mesh fraction present in the feed. It would
also be useful to develop possible alternatives to screen bowls, which is a high-priority research



                                                 14
                                        DRAFT
                                       October 28, 2002

item. It should be of particular interest to study the effect of slimes (-5 microns) loading on
throughput, moisture, and recovery. Studies should also be conducted on the classification that
occurs in the pool section of a screen bowl centrifuge, process control, and minimizing wear.

In the near-term, fundamental research to improve our basic understanding of screen bowl
technology should be carried out.

Filtration

Filtration is a process of separating liquid (e.g., water) from a particulate material by selectively
retaining the latter on a porous medium. Its driving force is the pressure drop across the medium
and the filter cake formed on it, and the rate of filtration depends on various physical and
chemical parameters. For relatively coarse particles, vacuum filters are used. For materials
containing large amounts of ultra fine particles, pressure filters are more effective. Various
chemicals are used to facilitate filtration.

Under current environmental constraints, it is becoming increasingly difficult to obtain permits for
slurry impoundments; therefore, belt presses will play a much larger role in coal preparation. Belt
presses are useful for dewatering mineral slurries, including the refuse materials from coal
washing. The product moisture is low enough to be disposed of in gob piles and, thereby,
provides an alternative to impoundments. However, belt filters require large doses of flocculants,
which is a serious concern. Therefore, there is a need to improve belt presses, so that they can
be operated at lower flocculant dosages, while achieving lower moistures at higher throughput.
Alternatively, it may be necessary to develop an entirely new method of dewatering ultrafine
refuse materials. Such devices will be useful in minimizing or eliminating the use of fine coal
impoundments in the near future.

A high-priority research area should include studies of basic filtration mechanisms that may lead
to improvements of current technologies and even the development of revolutionary methods.
Developing novel dewatering aids to improve ultra fine coal dewatering would be of great benefit
to both coal and mineral industries.

Drying

Drying refers to the method of dewatering materials by thermal evaporation. Because of the high
latent heat due to the evaporation of water, it is inherently a costly process. When mechanical
dewatering methods cannot reduce the moisture to desired levels, thermal drying is often the only
option.

In general, it is necessary to dry coal fines to less than 8% for briquetting. Drying fine coal in a
rotary thermal dryer requires coarse coal to be added, so that the fines can readily flow through.
It would, therefore, be of interest to develop a small-scale thermal dryer that can be used to dry
only the fines. Other innovative methods, such as chemical dewatering, microwave dewatering,
improved mechanical drying, may be explored. Recent investigations showed that fine coals can
be dried by displacing free water with another liquid (e.g., liquid CO2 or liquid butane) that can be
recycled. Improvements in briquetting/agglomerating processes for ultra fine coal is an area of
research that will lead to improving the efficiency and cost-effectiveness of coal product
development.

Automation, Controls, and Sensors

Improvements in automation, control, and sensor technologies are a challenge that could work to
improve solid-liquid separation technologies. Advances in on-line analysis would greatly increase
productivity. There is a need to develop techniques and algorithms that can control the operation
of classifier, screen bowl centrifuge, froth flotation, and thickener circuit. The control system must
be user-friendly and cost-effective.



                                                15
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                                             October 28, 2002


Exhibit 5 shows the areas for R&D emphasis for solid-liquid separations. The research is
organized by near-term (0-3 years), mid-term (1-4 years), and long-term (11+ years).

                      Exhibit 5. Solid-Liquid Separations Research
    Area                       Near-term                     Mid-term                       Long-term
                               (0-3 years)                   (4-10 years)                   (11+ years)


    Thickening                   Increase the capacity
                                   per unit area of a
                                       thickener

                                 Improve thickener designs to increase settling rates,
                                           increase % solids in underflows


    Centrifugation                    Screen bowl
                                 fundamental research
                                    and alternatives
                                           (5)

                                Basic research on screen        Improve coal recovery,        Develop alternatives
                                    bowl technology             low moisture in screen          to screen bowls
                                                                   bowl centrifuges


    Filtration                   Development of Novel
                                   Dewatering Aids

                                Dewatering thickener underflow by belt presses;
                                 improve performance by more than 25 percent
                                          and reduce chemical cost
                                                      (5)

                                  Filtration efficiency by study/analysis of basic
                                        filtration mechanism, also applies to
                                                    centrifugation
                                                          (5)

                                Ultra-fine coal dewatering by pressure (plate and
                                       frame); means of reducing moisture
                                            content of discharge cake
                                                        (5)


    Drying                                                         Briquetting/
                                                             agglomeration of ultra-fine
                                                                       coal


                                                            Small thermal dryers: study
                                                              alternative fine drying
                                                                    techniques


    Automation/                                                Screen bowl centrifugal
    Controls/Sensors                                         (flotation) froth thickener:
                                                               techniques to measure;
                                                             algorithms to control; user
                                                             friendly and cost effective

Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.



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                                        October 28, 2002
CHEMICAL & BIOLOGICAL SEPARATIONS
Chemical separations are an essential step in the processing of commercial minerals, particularly
in the processing of metallic minerals. Biological separations are playing an increasingly
important role in processing of metal sulfide minerals. Any method in which desired minerals are
separated from unwanted materials through a chemical or biological process is included in this
area. These chemical and biological separation processes are grouped as follows:

•   Leaching
    o Chemical
    o Biological

•   Solution Concentration and/or Purification
    o Solvent Extraction
    o Ion-Exchange
    o Precipitation
    o Adsorption

•   Product Recovery
    o Electrolysis
    o Cementation
    o Precipitation
    o Crystallization

For each of these areas, there exist a number of challenges facing the industry. These
challenges limit the capacity and reliability of the U.S. mining industry. Exhibit 6 provides a list of
these challenges related to chemical and biological separations. Each of these challenges is
discussed in more detail in the next section.




                                                   17
                                                          DRAFT
                                    October 28, 2002
                Exhibit 6. Chemical and Biological Separation Challenges
Leaching                             Concentration and             Product Recovery               Crosscutting
                                     Purification

Chemical and Biological              Solvent Extraction            Electrolysis

• Alternative Lixiviants for         • Third phase formation       •   Electrolyte purification   • New paths of moving
    Cyanide                                                        •                                  innovative developments from
                                     • Adapt to zinc production        Anodic over potentials
•                                                                                                     the laboratories to
    New, more efficient and            and other commodities       •   Anode integrity
    economic process                                                                                  commercial prac tice more
                                                                   •   Byproduct removal              expeditiously and less
    chemistries                      Ion Exchange                                                     expensively.
•   New catalysts                                                  Precipitation                  •   Real time sensors
•   Enhanced or better control       • Lower cost and more
    of reaction times                                                                             •   Control systems for high
                                       robust ion exchange         • On-line assay of low             variability in feedstocks
•   New and low cost ox idizing        media for metals                atomic numbers for cost    •   Environmentally safe
    agents                           • Ion exchange-solvent            and reliability                flocculants and reagents for
•   Environmentally benign             exchange recovery of                                           end users
    leaching agents                    gold from cyanide leach     Cementation                    •   Interaction between
•   More efficient use of in-situ      solutions
                                                                                                      chemicals used in processing
    processes                                                      • New cementation                  plants
•   Reclamation of water with        Precipitation/                  systems for use with         •   Chemical development for
    high total dissolved solids      Adsorption                      new lixiviants                   clean up
    (TDS) and the use and                                          • Displacement reactions
    recovery of precipitated                                                                      •   Need knowledge of new
                                     • Activated carbon            • Processes for gold-              chemicals used
    minerals                           adsorption                    copper separations
•   Water process treatments         • New adsorbents
    for high brine solutions                                       Crystallization
•   Breaking down wash
    waters after leaching to                                       • Mechanics of crystal
    minimize waste treatment
                                                                       growth without fines
    (e.g. filtration, de-ionizing)
                                                                   • Monitoring crystallization
•   Monitoring performance
    solution flows in heap                                         • Methods to induce
    leaching                                                           crystallization
•   Particle characterization                                      • Low cost liners
    (surface and chemistry)
•   Biological methodology for
    leaching difficult materials
    (i.e., high carbonates,
    chlorides, fluorides)
•   Methods for combining
    leaching and recovery for
    base metals (similar to
    resin - in - pulp)
•   Hydrodynamic and
    thermodynamic models for
    leaching
•   New alternatives to
    smelting for sulfide ores
•   Hydrometallurgical
    treatment of copper sulfide
    concentrates
•   Heap leaching technology
    (permeability, unrestrained
    bed, and other design
    factors)




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Chemical and Biological Leaching
Leaching, the aqueous dissolution of a particular mineral component, usually the valuable
component, from insoluble material, is an important and common process in hydrometallurgy.
Leaching methods encompass the use of assorted chemicals, oxidizing or reducing agents,
elevated oxygen partial pressures, elevated temperatures, or biologically-catalyzed reactions. In
this document chemical leaching is defined as those dissolution methods that take place in the
absence of microorganisms. Biological leaching involves mineral dissolution in the presence of
microorganisms, which facilitate the leaching reaction. Both chemical and biological leaching
methods are practiced in vessels, heaps, or dumps.

An important issue facing chemical leaching practices is the use of cyanide as a lixiviant. A
lixiviant is an aqueous-based reagent that selectively extracts the desired metal from the ore or
material to be leached rapidly and completely. From this the desired metal can then be
recovered in a concentrated form. Cyanide solutions are extensively used to separate precious
metals (gold and silver) from crushed ores, concentrates, and enriched tailings. The precious
metals are dissolved into the solution, and in subsequent processing steps, metal is recovered by
concentration/purification methods from the solution. Cyanide solutions used for precious metal
extraction are considered by some as a health and environmental concern and in some states
cyanide use is becoming heavily regulated or banned. The industry lacks alternative lixiviants
that are environmentally benign, perform as effectively as cyanide, and are relatively inexpensive.
In the mid- to long-term, a research priority is to develop alternatives to cyanide as a lixiviants for
precious metal extraction.

There are limited options for effectively extracting metals from refractory (hard to process) sulfide
minerals, nor are there chemical extractants that can selectively leach a particular metal of value
from a suite of other minerals. Proposed alternative chemistries are ineffective or difficult to
control and/or have reaction times not economically viable. Current catalysts and oxidizing
agents used to enhance the leaching process are expensive, inefficient, and present new sets of
environmental issues that must be addressed.

Another challenge that needs to be addressed in chemical and biological leaching is the lack of
information on basic science phenomena associated with leaching. Additional knowledge in
areas such as particle characterization (surface or chemical characteristics) is needed.
                                                                                             2-
Bioleaching can suffer in the presence of certain anions, namely too much carbonate (CO3 )
mineralization which can increase the pH above the optimal for leaching, and the presence of
                                  -                -
excessive amounts of chloride (Cl ) and fluoride (F ) which induce toxicity. Fundamental
microbiological issues need to be investigated before resolution of these limitations can be
addressed.

Particularly desirable would be the development of technologies that allows for the simultaneous
leaching and recovery of base metals in the same vessel. Such technology, called carbon-in-pulp,
exists for the leaching of gold by cyanide and simultaneous recovery by activated carbon in the
same tank. A similar technology, which could recover base metals leached using sulfuric acid or
by bioleaching, incorporates a “resin-in-pulp” concept could realize a considerable cost savings.

The method of heap leaching has a number of challenges. There is a lack of new heap leach
technologies with regard to permeability, unrestrained beds, and other design factors. There is a
lack of understanding regarding the interaction and solution flows in the heap leaching bed and
lack of knowledge in the areas of hydrodynamic and thermodynamic chemical reaction in
leaching. An area of research to be considered investigates the kinetics for all leaching
processes and to develop methods to construct better heap designs, models, and monitoring
systems. Research in basic science, along with a better understanding through modeling of the
leaching process, can allow the industry to develop more effective and productive heap leaching




                                                19
                                         DRAFT
                                        October 28, 2002

practices. Also in the near- to mid-term, methods are needed for better heap particle size and
agglomeration control to improve permeability.

Another priority is to continue development of alternatives to smelting of sulfide minerals. Sulfide
minerals are those containing sulfur linked to a metal, for example pyrite (FeS 2), arsenopyrite
(FeAsS), or chalcopyrite (CuFeS 2). Smelting sulfide minerals produces sulfur dioxide gas (SO2)
and arsenic trioxide (As2O3) gas, the latter when arsenic-containing minerals are present.
Smelting is capital- and operating-cost intensive, largely owing to gas scrubbers, essential for
containing the SO2 and As2O3 emissions. Considerable progress has been made on some
smelting alternatives, for example pressure oxidation for the leaching of copper sulfide ores and
concentrates and the bioleaching of chalcopyrite concentrates in aerated, stirred-tank reactors.
However, much of the world’s chalcopyrite resources are low-grade, and therefore it is not
economically viable to concentrate these ores for pressure oxidation and stirred-tank bioleaching.
A heap leach process for extraction of the copper with recovery by solvent extraction/
electrowinning is the most desirable approach for these low-grade chalcopyrite resources.
Although bioheap leaching is successfully applied on a commercial basis for secondary copper
sulfide ores (chalcocite and covellite), heap leaching of chalcopyrite ore has yet to be developed.
The chemical and biological conditions under which chalcopyrite can be effectively leached are
relatively well defined. However, considerable innovation is required to control heap conditions
suitable for the bioleaching of chalcopyrite.

The ideal scenario for the mining industry is to employ in-situ leaching for the extraction of base
and precious metals. In-situ leaching is a process of extracting valuable components of a mineral
deposit without physical removal of the rock. In-situ leaching entails the extraction of the desired
metal using aqueous solutions. Although the technology has many environmental advantages
over conventional mining practices, because there is little land disturbance and no aboveground
solid wastes are generated. The technology is successfully used for the extraction of uranium
from certain types of permeable sandstones and has been demonstrated for copper extraction,
however, much technology must be developed before in-situ leaching can be effectively used.
Major issues center around fracturing of the deposit so lixiviants can contact the metal-bearing
minerals and confinement of the lixiviants to prevent groundwater contamination.

Recovery and reclamation of the water used in processing is another issue in leaching. Leach
solutions with high total dissolved solids (TDS) and high brine content solutions are difficult and/or
costly to reclaim. It would be beneficial if the precipitated minerals from barren leach solution
(that is, solutions containing no metals of value) could be recovered and reused. New techniques
to break down wash-waters to minimize waste treatment are needed by the industry. A priority
research area is to develop better water recovery and treatment methods for leaching processes.
Water effluents and source water are issues in many industrial processes, particularly in the
West, where water is scarce.

All research efforts listed below in Exhibit 7 should result in in-situ processing in the long-term for
the industry.




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               Exhibit 7. Chemical and Biological Leaching Research

    Area                       Near-term                  Mid-term                     Long-term
                               (0-3 years)                (4-10 years)                 (11+ years)


    Chemical &                  Water recovery and
    Biological Leaching            treatment for
                                leaching processes
                                        (4)

                                Studies of kinetics
                                  for all leaching
                                    processes
                                          (3)

                                 Particle size and
                                 agglomerates for
                                   permeability
                                         (3)

                                 Develop environmental benign leaching agents

                                    Heap design, modeling, and monitoring

                                                                         Alternatives to cyanide
                                                                                   (3)

                                                                Alternatives to smelting sulfide ores
                                                                                 (1)

                                                                                     In-situ processing

Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.



Solution Concentration and/or Purification
Solution concentration and purification are required processing steps in leach solution
hydrometallurgy. Leaching solutions are typically dilute, and it is necessary to increase the
concentration of the valuable component and/or to remove impurities prior to product recovery.

Solvent Extraction

Solvent extraction is the selective transfer of a specific component from the aqueous leach
solution into an immiscible organic phase, from which that compound is subsequently stripped off
into a purified and concentrated phase.

Within the area of solvent extraction, difficulties with third-phase formation exist. An intermediate
phase forms between the organic phase and the aqueous phase when the organic solvent and
the aqueous phase form an emulsion. This emulsion can be induced by dissolved silicates, clays,
and/or abundant development of microbial growth. The third phase prevents separation of
organic and aqueous phase with the loss of organic reagents and valuable metal. Several




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emulsion formation results in poor transfer of the metal from the aqueous phase to the organic
phase. At worst the organic extractant must be replaced, which is very costly.

Solvent extraction is principally used for the recovery of copper from leach solution. With
increased use of leaching for other metals the adaptation of solvent extraction for concentration
and purification processes for zinc and other commodities that currently do not use this method of
recovery and concentration would benefit the industry.

Studies are needed to develop a new systems approach to solvent extraction and to expand its
application into other mineral separations. In conjunction with the new system approach, new
solvent/solute mixtures are needed in the mid-term.

Ion Exchange

Ion exchange is the selective exchange between an ionic component in a leach solution and an
ion attached to a porous polymeric resin bead. Stripping of the loaded resin then produces a
purified and concentrated aqueous phase from which the desired product can be recovered.

The quality of ion exchange media is an issue facing the industry. Current media is costly and
not robust enough to meet the needs of the industry. There is a lack of knowledge about ion
exchange/solvent-extraction recovery of gold from cyanide leach solutions. There is also a need
for resins for selective recovery of by-product metals, such as nickel, cobalt, and zinc from acidic
copper leach solutions.

Tests for alternative ion exchange materials are a priority. These tests should yield alternative
ionic solutions and resins for separations in the mid-term. The developments of new ion
exchange resins are needed. These new resins need to be robust and selective as well as have
increased capacity. More rapid rates of exchange and regeneration chemistry also are needed.
Research is needed to combine unit operations to increase efficiency and productivity. Other
strategies are to develop magnetic or other resin particle properties that will provide alternative
resins/solution separations for more effective and productive systems.

Precipitation and Adsorption

Precipitation is typically used to remove impurities from the leach solution. Impurities are
precipitated by chemical reaction with an appropriate reagent and/or by adjusting the temperature
and pressure of the system. The particulate phase is then removed prior to product recovery
from the solution. Alternatively, the valuable component can be removed as the precipitate
material and subsequently refined for product recovery.

Adsorption is similar to ion exchange in the sense that the reactant is immobilized. A dissolved
component of the leach solution, usually the valuable component, is removed from the leach
solution by the reaction with the adsorbent. The removed material is stripped from the adsorbent
and recovered in a second step. Challenges for precipitation and adsorption are mainly related to
activated carbon adsorption processes as well as a general need for new and more specific
adsorbents. There is a research need to develop new ways of producing low cost and more
efficient absorbents. Better communication between absorbent producers and industry will aid in
meeting industry specific needs.

Exhibit 8 shows the areas of R&D emphasis for concentration and purification research. The
research is organized by near-term (0-3 years), mid-term (4-10 years), and long-term (11+ years).




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                 Exhibit 8. Concentration and Purification Research
    Area                      Near-term                 Mid-term                      Long-term
                              (0-3 years)               (4-10 years)                  (11+ years)



    Solvent Extraction                         Studies for new solvents and applications

                                                             Solvent/solute
                                                            mixtures for more
                                                             utilization and
                                                              applications


    Ion Exchange                            Testing of alternative materials for exchange
                                                                  (1)

                                                             Alternate ionic solutions and resins for
                                                                           separations
                                                                                (1)

                                                            Magnetic or other particle properties for more
                                                                   effective separation systems

                                                         Ion exchange resins that are robust, selective,
                                                                and with an increase in capacity

                                                                       More rapid exchange and
                                                                        regeneration chemistry


    Precipitation/              Communications between absorbents producers and industry to better
    Adsorption                                       meet industry needs

                                               Low cost and more effective absorbents

                                                Improved activated carbon technology

Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.



Product Recovery
Product recovery is the final step in hydrometallurgical processing. Product recovery generally
involves removal of the product from the concentrated and purified leach solution. Invariably, this
will be a solid material recovered using electrolysis, precipitation, cementation, crystallization,
and/or membrane separation technologies.

Electrolysis

In electrolysis, the product is recovered electrolytically as a deposit that forms on an electrode.
There are a number of challenges related to electrolysis. Used electrolytes, which are fluid
nonmetallic electric conductors, need better reclaiming and purification processes. There are
issues with anodic over potentials contributing to energy costs and with anode integrity. Issues
also must be resolved for byproduct removal from mineral processing.




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More effective electrolyte additives are needed to benefit the electrolysis process. New anodes
and the reduction of anode degradation are areas for research.

Precipitation

Product recovery in precipitation is achieved by precipitating the desired component out of
solution with an appropriate reagent. Precipitation processes can be enhanced with access to
on-line, real-time assays on low atomic numbered elements, but instruments need to be low in
cost and high in reliability. With more readily available information, the mining industry could
make better-informed decisions regarding processes efficiencies.

Cementation

Cementation is the process through which a metal ion in solution is displaced and precipitated by
a more active metal. For instance, zinc dust is used to precipitate gold and silver from cyanide
leach solutions, or copper and nickel from acidic zinc-leach solutions. Until the advent of the
solvent extraction/electrowinning process, scrap iron was used universally to recover copper from
the leach solutions. In cementation processes, a systems approach might prove beneficial.
Systems that combine cementation processes with other processes may increase productivity
and increase efficiency by reducing or eliminating other process steps. In addition, cementation
is the only option available to recover gold form solutions where alternative lixiviants are being
used instead of cyanide. There is also a lack of knowledge in displacement reactions as well as
overall processes for gold-copper separations.

Crystallization

Crystallization occurs when changes in concentration, temperature, and/or pressure cause the
formation of crystals to occur from saturated solutions. A larger knowledge base is needed in
basic crystallization sciences in order to assist in the processes. For example, more knowledge
on the mechanics of crystal growth to reduce fines or better methods to induce crystallization
could greatly benefit the industry. Better methods of monitoring crystallization systems are
needed to study these phenomenons.

Evaporators are costly and inefficient in processing soluble minerals such as potash and trona.
In the evaporite mineral industry, multiple effect evaporators have been evaluated. Their high
energy and capital costs prevented their acceptance into industry. A priority research area is low-
cost liners for ponds and settling basins such as solar evaporation ponds. Another priority
research area is the study of crystallization and nucleation, including surfactant effects. In the
mid-term, alternatives to evaporators, or more effective evaporators are needed.

Membranes

Membrane science has the potential to provide the industry with new alternatives to many
separation processes. Currently, high dissolved solid solution membrane pluggage has
prevented the use of membrane technology. This research area could significantly benefit the
industry. The development of more robust and self-cleaning membranes is a near- to mid-term
research need. In the long-term, the development of selective metal transport membranes is
desired to better separate the valuable material.

Exhibit 9 shows the areas for R&D emphasis for product recovery. The research is organized by
near-term (0-3 years), mid-term (4-10 years), and long-term (11+ years).




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                                       October 28, 2002
                             Exhibit 9. Product Recovery Research
    Area                      Near-term                   Mid-term                Long-term
                              (0-3 years)                 (4-10 years)            (11+ years)


    Electrolysis               Electrolyte additives

                                                             Anode degradation

                                                               New Anodes

    Precipitation                Low-cost, high-reliability, on-line, real-time
                                 assays on low atomic numbered elements


    Cementation                     Studies on            Systems approach to
                                   displacement               cementation
                                     reactions                 processes


    Crystallization            Low-cost liners for
                                   ponds and
                                 settling basins
                                        (2)

                                Studies on crystallization and nucleation,
                                    which include surfactants effects
                                                    (2)

                                                          Effective evaporators
                                                            or alternatives to
                                                               evaporators



    Membranes                         Robust, self-cleaning membranes

                                                                                       Selective metal
                                                                                          transport
                                                                                        membranes


Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.



Crosscutting
Many challenges crosscut the areas of chemical and biological separations. For example, there
is a delay between the development of new processes and technologies to commercial practice.
Also, the development of real-time sensors would benefit the entire chemical separation area.
Control systems is another area where further development would benefit the industry.

There is a need for improved chemical safety related to the potential combinations of flocculants
and reagents used by the industry. Communication and the development of a knowledge base of
the effects of chemicals used in mining are needed. Better interaction between chemical
developers and processing plants will help to develop new chemicals that may help industry solve
some environmental issues.




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There are a number of near- to long-term research needs that crosscut the chemical and
biological separations areas. They are:

•   Performing basic research on reaction kinetics
•   Improving process efficiencies for all chemical separation
•   Developing more incentives to perform R&D within the industry
•   Increasing technology transfer and modification from other closely related industries
•   Increasing cooperation between industry and the public
•   Collecting data on the performance of available and new chemicals
•   Improving and performing research in upstream processes such as geology or drilling and
    blasting techniques

Mid- to long-term crosscutting priority research areas are:

•   Developing new alternatives to treating source water
•   Increasing cooperation with industry and sensor manufactures to develop low-cost real-time
    sensors to better meet the needs of industry.
•   Developing monitoring sensors that do not require radioactive sensors

Exhibit 10 shows the areas for R&D emphasis that crosscut the leaching, concentration/
purification, and product recovery areas. The research is organized by near-term (0-3 years),
mid-term (4-10 years), and long-term (11+ years).




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                                                 DRAFT
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Exhibit 10. Crosscutting Research for Chemical and Biological Separations
    Area                       Near-term                   Mid-term                     Long-term
                               (0-3 years)                 (4-10 years)                 (11+ years)


    Crosscutting                                        Basic research on kinetics
                                                                   (1)

                                                  Process efficiencies for all processes
                                                                   (1)

                                                              Incentives for R&D
                                                                      (1)

                                  Technology transfer and modifications from other industries such as
                                                             chemicals

                                                  Cooperation between industry and public

                                             Performance data on chemicals available to industry

                                Studies in upstream processes such as geology and drilling and blasting

                                                                 Alternatives to treating source water
                                                                                   (1)

                                                               Low-cost sensors through cooperation with
                                                                         sensor manufacturers

                                                                 Real-time sensors to measure reduction
                                                                               oxidation

                                                              Low cost or alternatives to radioactive sensors

Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.




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                                       October 28, 2002
ENVIRONMENTAL CONTROL
Effective environmental controls are a critical component of sustainable mining and mineral
processing practices. Environmental control activities used in mining include prevention,
abatement, remediation, and reuse of process residues, byproducts, and waste materials.

Environmental control in the U.S. mining industry is dictated in large part by various
environmental regulations. Increased environmental performance data and opportunities
available through environmental control methods can help educate decision-makers. This will
result in more comprehensive environmental regulations in the future, avoiding "reactive
regulations." Challenges related to environmental control may be subdivided into three areas:

•   Emissions control
    o Sulfur
    o Trace Elements
    o Fugitive Dust

•   Remining
    o Mining
    o Separations
    o Disposal

•   Waste Disposal
    o Acid Mine Drainage
    o Impoundments
    o Fly Ash
    o Recycle Water

The fundamental chemistry and chemical behavior of mercury, sulfur, and other regulated
elements is of prime interest to the industry. Understanding how these elements will react over
time is a necessary component for long-term planning for the life of the mine, including mine
closure.

Exhibit 11 lists major environmental control challenges identified by industry related to the topics
of emissions control, remining, and waste disposal.




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                                                        DRAFT
                                         October 28, 2002
                          Exhibit 11. Environmental Control Challenges

 Emissions Control                 Remining                                         Waste Disposal

 Sulfur                            Separation                                       Recycle Water

 • Finding uses for sulfur/trace   • Lack of efficient, cost-effective dewatering   • Minimizing water usage while maximizing recycling
   elements                          technologies                                     of process water
 • Understanding the importance    • Improved technologies for impoundment          • Balancing the need to maximize effective water use
   of sulfur in the environment      remining/blending of feedstock                   with the need to avoid toxics build up
                                                                                    • Presence of heavy metals and water chemistry
                                   Mining                                             inhibiting separation
 Trace Elements                                                                     • Total Maximum Daily Load (TMDL) requirements for
                                   • New equipment for remining that allows           streams and rivers requires purification of discharge
 • Fundamental understanding         you to tap tailings and piles                    water
   of mercury chemistry            • Underdeveloped market for remining
 • Efficiency improvements in      • Regulatory constraints that may preclude       Fly Ash
   mercury removal                   remining (reclamation liability)
 • Removal of mercury and                                                           • Fly ash and mercury interaction
   arsenic pre-combustion          Disposal                                         • Cost of separation technologies
 • NOx coupled with mercury                                                         • Dry separation of fine particles
   oxidation                       • Making fine refuse more transportable –        • Bringing Fly Ash and Flue Gas Desulfurization
                                     possible reduction of moisture                   products to market as value added products
                                   • Development/approval of new impounding         • Wet processing of fly ash
 Fugitive Dust                                                                      • Cost of drying after flotation separation
                                     structures
                                   • Lack of mine planning to facilitate
 • Control of fine particulates      underground fines disposal                     Impoundment
   from surface mining and         • Structural stability of waste dumps
   transport of ore                • Energy recovery from fine coal waste           • Structural stability of dewatered fine coal waste and
                                   • New fertilizers using phosphatic clays           all other mineral waste
 Other                                                                              • Structural stability for non-impounding structures
                                                                                    • Economics and efficiency of dewatering fine coal
 • Better understanding of                                                            waste vs. disposal of slurry in impoundments
                                                                                    • Refuse variability
   techniques related to fly ash
   and trace elements
                                                                                    Acid Mine Drainage (AMD)
 • Iron pyrite market
   development                                                                      • Precipitation of iron and other elements from water
 • Control of Hg, Se, and other                                                       in streams
   trace elements in waste                                                          • Waste characteristics over the 10, 20, 30-year
                                                                                      legacy
                                                                                    • Unexpected reactions in spent leach pads
                                                                                    • Mitigating run-off contact with water
                                                                                    • Long-term acid generation from waste dumps




Emission Control
Emission control deals with the emissions generated from the processing and separation of
mined materials. This is the focus of strong regulatory scrutiny. For example, the 1990 Clean Air
Act Amendment (CAAA) limits emissions of acid-rain precursors and hazardous air pollutant
precursors (HAPPs) from coal-burning power plants.

The ability to use separation processes for controlling mercury emission is of critical importance
for the industry. The Environmental Protection Agency (EPA) will soon promulgate mercury
emission standards, which will be serious constraints under which the coal industry must operate.
Research and technology development to address emissions control is essential for enabling the
mining industry to meet environmental standards while maintaining economic competitiveness.




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Sulfur

The CAAA limits sulfur dioxide (SO2) emissions from coal-burning power plants to 8.9 million tons
per year, even though the United States will continue to rely on coal for meeting increased
electricity demand. While scrubbers and fuel switching may be used to minimize SO2 emissions,
advances in pre-combustion coal cleaning technologies can substantially remove inorganic sulfur.
Further research may lead to the development of technologies that can remove organic sulfur as
well. Continued R&D to remove both inorganic and organic sulfur will benefit the coal companies
mining high-sulfur coals. Availability of innovative pre-combustion coal desulfurization
technologies allows greater utilization of domestic energy resources for the energy needs of the
nation.

Trace Elements

The 1990 CAAA lists various trace elements present in coal as HAPPs. Much of the trace
elements, such as mercury are associated with the mineral matter present in coal. While the
utility industry is preparing to comply with the new regulations by using post-combustion
scrubbers, improved pre-combustion coal cleaning technologies may also be used to remove
trace elements from coal. At present, the cost of removing mercury form lignite is estimated at
$65,000 per pound of mercury removed. Studies to better understand the chemistry of mercury
will be critical in coping with the new environmental regulations. The generic knowledge of
mercury can be used to identify lower cost options for removing mercury from coal. The basic
research on the mercury chemistry, its association with various inorganic and organic matter in
coal, and its partitioning during combustion may lead to the development of innovative
technologies. The studies on mercury will also lead to the methods of removing other trace
elements such as arsenic, lead, and vanadium from coal prior to combustion.

Fugitive Dusts

At various stages of producing, transporting, and storing coal, ultra fine particles become
airborne, creating public concerns and affecting worker health. Research is needed to monitor
and control the fugitive dusts generated during mining and transportation.

Crosscutting

Currently, emission control strategies are developed and implemented on a piecemeal basis, one
pollutant at a time. A proactive, integrated approach is needed for controlling a range of
emissions such as NOx, SOx, particulate matter, and trace elements. This could include
technologies applied at the pretreatment stage or at the stack. The range of emission control
technologies currently in use should be investigated to identify opportunities for an integrated
method for emission control. New technology that builds on existing R&D is needed to remove
sulfur, mercury, pyrite, and heavy metals with minimum carbon loss.

Tools for improved decision-making need to be developed as a way to minimize emissions
associated with various mining activities. Specifically, industry could profit from the development
of techno-economic models for evaluating different technology options. This should lead to
testing and demonstrations and ultimately to case studies that could be used to educate both
industry and regulators.

Research is needed to identify new uses for the captured sulfur and trace elements.
Development of revenue-generating markets for these emissions/byproducts will reduce the net
cost of emissions control to the industry

Exhibit 12 shows the areas for R&D emphasis for emissions control. The research is organized
by near-term (0-3 years), mid-term (4-10 years), and long-term (11+ years).




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                         Exhibit 12. Emissions Control Research
     Area               Near-term                          Mid-term                      Long-term
                        (0-3 years)                        (4-10 years)                  (11+ years)


    Emissions        Fundamental research             Techno-economic                  In-situ leaching
    Control           to better characterize         models for evaluating         (mining and extraction)
                             species                   control options
    • Sulfur                    (3)                           (2)                  Organic sulfur removal
                                                                                          process
    • Trace            Understand mercury             Improved sampling
      Elements          chemistry and its                and analytical
                           reactions                 techniques to assess
    • Fugitive                                          the presence of
      Dust             Proactive, integrated           mercury and other
                     control approach to NOx,             impurities in
                      SOx, particulate matter,      unprocessed materials
                        and trace elements                    (2)
                              capture
                                                     On-line integrated suite
                         Remove sulfur,                of tools to analyze
                      mercury, pyrite, and                properties and
                       heavy metals with             characteristics in real-
                      minimum carbon loss                      time
                              (4)
                                                       Characterize species
                      Markets for pyrites and
                                                      through life-cycle from
                          heavy metals
                                                     deposit to processing to
                                                     waste disposal/recycling

                                                     Decision-making tool to
                                                        evaluate different
                                                       technology options


Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.



Remining
Remining can capture the valuable materials contained in coal and mineral industry wastes. New
and advanced technologies can increase the economic feasibility of capturing valuable
components by remining.

The coal and mineral industries generate significant amounts of wastes that may contain valuable
materials. They can be recovered economically using advanced separation technologies.

Separation

According to a recent National Research Council report, there are 713 fine coal impoundments in
the U.S., mostly in the Appalachian coalfields. These impoundments have been created due to
the difficulties in separating coal from mineral matter and disposing of the latter in environmentally
and economically acceptable manner. It is estimated that more than 2.5 billion tons of fine coal
has been discarded in the impoundments. Even today, 70-90 million tons of fine coal is being
discarded each year. The fine coal impoundments represent a waste of valuable natural


                                                    31
                                        DRAFT
                                      October 28, 2002

resources, significant loss of revenues to coal companies, and serious environmental concerns to
public, all of which have been created due to the lack of appropriate separation technologies.
Therefore, there is an impending need to develop advanced separation technologies that can
eliminate fine coal impoundments in the future.

Of the various technologies that can be used to eliminate impoundments, removing water from
both coal and refuse poses the most significant difficulty. For this reason, the industry panel has
identified dewatering as a top-priority research item in the Unites States, particularly the
dewatering of refuse.

The industry also suggested that in-situ leaching be incorporated into the remining process, which
may be applicable for the base-metal industry.

Mining

Materials containing significant amounts of valuable components are excavated from waste piles
and impoundments using the appropriate mining methods and moved to a facility where the
valuable components are separated from valueless material. Providing a consistent feed stream
to the separation facility in the most economical and environmentally acceptable manner is
important in remining operations. Development and approval of new impounding structures
would increase the viability of remining operations. This includes mine planning to facilitate
underground fines disposal. Improved technologies for impoundment remining and blending of
feedstock would also increase the feasibility of remining. Sensor technologies are needed to
improve waste characterization and assess the presence of valuable materials. Research is
needed to explore and improve the structural stability of waste dumps as well as predict how
stockpiles change over time.

In addition, research and demonstration projects focused on new ways to process ores in
remining should be pursued. The development of new equipment to allow remining of tailings
and piles would increase the amount of materials that can potentially be remined. New
equipment to capture smaller, hard-to-get reserves is also needed. Technologies from other
industries that can be used in remining for extraction and processing should be explored.

Disposal

The unwanted materials generated from the waste recovery operations are disposed of,
sometimes back in the waste pile or in the impoundments where they originated, or back to old
mine workings. In the former, care is taken not to impair remining operations. In the latter, care
is taken so that the refuse materials do not contain hazardous elements that can potentially
contaminate ground water.

Crosscutting

Developing improved methods of characterizing impoundments and tailings ponds is a high-
priority. Advanced sampling techniques will be useful for mapping impoundments accurately.

Possibilities to recover energy from waste ponds by in-situ gasification should be explored.
Recycling building materials may also be of interest.

Regulatory constraints may act as barriers to the application of new separation technologies for
remining. For example, liability issues associated with remining need to be addressed.
Educating the regulatory community through demonstration projects that prove/substantiate the
applicability of new technologies is identified as a high priority. A major issue for improving
environmental control is to develop valid database and conduct case studies in order to
demonstrate the effectiveness of the new environmental control technologies. For example, the
liability associated with reclamation is constraining the extent of remining that the industry is



                                               32
                                             DRAFT
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willing to pursue. Information that can demonstrate the environmental benefits of remining, in the
context of the full mining life-cycle, would help validate the benefits of remining. Case studies,
improved data, and demonstration projects can increase regulators' comfort with new
technologies, and enable them to reinterpret regulations that may be preventing the application of
remining. Tax incentives for sustainable mining operation is desirable.

Exhibit 13 shows the areas for R&D emphasis for remining. The research is organized by near-
term (0-3 years), mid-term (4-10 years), and long-term (11+ years).

                                   Exhibit 13. Remining Research

    Area             Near-term                       Mid-term                          Long-term
                     (0-3 years)                     (4-10 years)                      (11+ years)


   Remining               Methods to                      Processing ores in             In-situ leaching in
                        characterize and                      remining                        remining
   • Separation      quantify value of waste
                               (3)                  Demonstration projects             Dewatering technology
   • Mining                                          to prove/substantiate              for refuse side, not
                       Equipment to capture           applicability of new                   clean side
   • Disposal           smaller, hard-to-get               systems
                             reserves                         (3)                      Energy recovery from
                                                                                           waste ponds
                      Sampling technology to        Prediction models of how
                       map constituents of           stock piles change over
                          slurry ponds                         time

                      Types of equipment to               Information to help
                     capture smaller, hard-to-           regulators reinterpret
                           get reserves                       regulations

                      Technologies from other             Ultra fine particle
                      industries for extraction          separation methods
                          and processing

                        Combine knowledge
                          across industry,
                     researchers, & regulators
                      to define a path forward

                          Remining civil
                           construction
                               (1)

                        Database and case
                     studies on environmental
                           technologies


Strategies in bold are a priority.
Strategies in bold-italics are a high priority.
Note: ( ) is the number of votes received making the given strategy a priority area.




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                                       October 28, 2002
Waste Disposal
Waste disposal focuses on waste generated from the extraction, beneficiation, and utilization of
mineral commodities that must be disposed of in an environmentally acceptable manner. The
waste can consist of both solid and liquid components with a wide range of properties depending
on the types of minerals and processes involved. The nature of these wastes and the effects of
their long-term storage play a large role in the waste disposal issues related to acid mine
drainage, impoundment, fly ash, and recycle water.

Acid Mine Drainage

Acid mine drainage consists of leachate resulting from the oxidation of sulfur associated with
waste or from exposed pyrite in old workings. The ability to predict the long-term effects of waste
dumps can drastically improve the mining industry’s capacity to mitigate the effects of acid mine
drainage.

To accomplish this task, better understanding of waste characteristics is required. Specific types
of the materials present in mine wastes must be known to predict the potential bio- and geo-
chemical reactions. In addition, better data and analysis methods are needed to predict the water
chemistry of the run-off going into spent leach pads. For example, unexpected reactions
sometimes occur when run-off enters the pads that result in the creation of cyanide. An improved
understanding of the precipitation of iron and other elements from water in streams is also
needed. Additional preventative methods must also be examined, such as the development of
soil buffers to reduce contact with water.

Impoundment

An impoundment consists of a permanent storage structure for either coal or mineral processing
waste including an impounding structure and a basin. Typically, the waste consists of a mixture
of water and fine particles less than 100 mesh. A major cause of problems in impoundment
structures is that the basin material is often not fully understood. Unknown geology or old mine
workings can impact the stability of an impounding structure. Better understanding the stability of
the basin material, particularly in older impoundments, will increase the industry’s ability to
safeguard them. Typically, impoundments that fail are older structures built before current stands
were put in place.

Research is needed on the structural stability of impounded, dewatered fine coal waste and all
other mineral waste, whether from coal washing, fly ash, iron mining, or other mining operations.
Stability for non-impounding structures is also needed. Studies to explore the economics and
efficiency of dewatering fine coal waste versus disposal of slurry in impoundments would also be
beneficial.

Refuse variability is another key issue related to impoundments. Research is needed to develop
predictive models to profile refuse streams. Optimizing the ability to split between coarse, fine,
and ultra fine waste materials would also help to reduce problems associated with refuse
variability.

Bioremediation in the form of cultivated, hyper-accumulating plants to take up impoundments and
old tailings are a strategy to reduce the impact of impoundments on the natural surroundings.

Fly Ash

Fly ash is the ultra-fine byproduct of coal combustion captured from the exhaust stream. It is
generally alkaline in nature with strong pozolanic qualities and may contain significant amounts of




                                                34
                                        DRAFT
                                       October 28, 2002

unburned carbon. Improvements to fly ash capture and disposal through carbon control/burnout
is a key issue. Examples of research needs include:

      •   Better understanding of fly ash and mercury interaction is needed to increase mercury
          capture
      •   Methods of using fly ash for flue gas desulfurization and developing new markets need
          to be investigated
      •   Efficient methods of removing unburned carbons from fly ash
      •   Low-costs methods of dewatering fly ash
      •   High efficient dry separation of fly ash

Recycle Water

The mining industry is faced with the difficulty of maximizing effective water usage while avoiding
toxic build up in its separation processes. Recycle water provides a means of increasing the
usefulness of process water. Recycle water is water decanted from clarification processes that is
reused in mining or mineral processing applications. Minimizing water usage, while maximizing
recycling of process water, is critical to sustainability in the mining industry. Research is needed
to address the detrimental effects of various heavy metals present in recycled water. Some of the
heavy metals, e.g., copper and lead ions, can inadvertently activate unwanted minerals (e.g.,
pyrite) and cause them to float non-selectively, making the separation difficult. Therefore, it is
necessary to study the effects of the various heavy metal ions present in recycled plant water.
When plant water is discharged, it is necessary to remove the heavy metals to meet Total
Maximum Daily Load (TMDL) requirements. Therefore, it is also necessary to develop low-cost
water treatment methods.

Overall, strategies to address waste disposal issues highlight the need to develop methods for
predicting basic chemical behavior over the lifetime of a waste species. A high priority is placed
on predictive methods for forecasting long-term water quality from waste dumps, including
biological systems. This involves understanding the chemistry/biochemistry of disposal systems,
including cyanide. In addition, a more comprehensive economic study of the waste disposal
problem is needed in order to support the sustainability and techno-economic cost/benefit of
different technologies. Exploration to identify components of waste that can be reused/sold is
also needed.

Improved, cost-effective dewatering capability is also cited as a main focus area for waste
disposal research. New dewatering technologies that can meet the high-throughput requirement
are identified as a high priority research activity. Dewatering technologies that can withstand
harsh environments, such as rock beating, are also a desired feature. Adapting other
technologies with ideal characteristics to perform dewatering is a possible route to achieving
these improvements.

In the long-term, the mining industry is moving toward development of technologies to enable
near-zero waste disposal. Achieving near-zero waste disposal will require improvements in
waste product utilization as well as developing the ability to use parts of one waste stream to treat
another stream, such as the ability of waste to improve growth/re-growth of used areas.

Exhibit 14 shows the areas for R&D emphasis for waste disposal. The research is organized by
near-term (0-3 years), mid-term (4-10 years), and long-term (11+ years).




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                                                DRAFT
                                       October 28, 2002
                            Exhibit 14. Waste Disposal Research
    Area                Near-term                     Mid-term                     Long-term
                        (0-3 years)                   (4-10 years)                 (11+ years)


    Waste                  Economic study of          Predictive methods for          Cultivate hyper-
    Disposal:                waste disposal            predicting long-term        accumulating plants to
                          problem to support            water quality from         take up impoundments
    • Acid Mine          different technologies           waste dumps                  and old tailings
      Drainage                      (1)                         (5)

    • Impoundment                                                                        Nero-zero waste
                         Identify components of            Technologies for                 disposal
                            waste that can be               improved water
    • Fly Ash
                               reused/sold                    treatment                 Enhance ability of
                                                                  (2)                  waste to improve the
    • Recycle
                          Pumping underground                                          growth/re-growth of
      Water
                                                      Higher throughput for                used areas
                          Identify value-added             dewatering
                         opportunities for fly ash              (7)                Use parts of one waste
                                                                                   stream to treat another
                                                           Understanding                waste stream
                                                       chemistry/biochemistry
                                                        of disposal systems

                                                      Dewatering technologies
                                                      that can withstand harsh
                                                            environments

                                                       Optimizing the ability to
                                                        split between coarse,
                                                      fine, and ultra fine waste
                                                               materials

Strategies in bold are a priority
Strategies in bold-italics are a high priority
Note: ( ) is the number of votes received making the given strategy a priority area.




                                                      36
                                          DRAFT
                                       October 28, 2002
CONCLUSION
The Center for Advanced Separation Technologies (CAST) represents a consortium of seven
universities, which include Virginia Tech, West Virginia University, University of Kentucky,
Montana Tech, New Mexico Tech, University of Nevada-Reno, and University of Utah. These
universities have strong research programs in coal cleaning, mineral processing, and
environmental control research. In an effort to identify its direction of research in the future, a
workshop was held in Charleston, West Virginia, August 14-15. Many of the major minerals and
coal companies participated at the workshop, and discuss the technological needs for the U.S.
coal and minerals industries and identified research priorities.

At the workshop, industry representatives were divided into three groups: 1) physical separation,
2) chemical/biological separation, and 3) environmental control. Each group identified specific
research needs and classified them in to near-, mid- and long-term priorities. The document
presented here will be used as roadmap for the future research at CAST. It will also be used as
guide for the faculty members of the participating universities in preparing their research
proposals, which will be reviewed by industry panels for funding. In general, the industry panel
recommended fundamental research to be conducted at CAST, with objectives for industrial
applications. Incremental improvement in existing technologies may satisfy the industry needs in
a short-term; however, there is a need for revolutionary technology development in many different
segments of the U.S. mining industry.




                                                 37
          DRAFT
        October 28, 2002




        APPENDIX A


CAST WORKHSHOP PARTICIPANTS




               A-1
                                            DRAFT
                                         October 28, 2002
Appendix A

                             CAST Workshop Participant List

Note: Names in italics submitted a registration form but were unable to attend the meeting; however, they
are invited to participate in the review processes.



Frank Addison                                            Corale Brierley
Coastal Coal                                             Brierley Consultancy LLC
1014 Laurel Avenue                                       PO Box 260012
 P.O. Box 1578                                           Highlands Ranch, CO 80163
Coeburn, VA 24230                                        Phone: 303-683-0074
franklin.addison@elpaso.com                              clbrierley@msn.com

Daryoush Allaei                                          Gary Cox
Smart Screen Systems, Inc.                               Teco Mining
610 West Drive Ave.                                      Feds Creek, KY 41524
P.O. Box 191                                             kycox@tecoenergy.com
Chisholm, NM 55719-0191
dallaei@grdc.com                                         Asad Davari
                                                         West Virginia University
Barbara Arnold                                           Phone: 304-442-3205
PrepTech, Inc.                                           adavari@wvu.edu
532 Route 66
Apollo, PA 15613                                         Phil Davis
Phone: 724-727-3439                                      Peabody Energy
barnold@preptech.com                                     701 Market Street
                                                         GW*
Richard Bajura                                           St. Louis, MO 63010-1826
West Virginia University                                 Phone: 341-342-7512
National Research Center for Coal and Energy             pdavis@peabodyenergy.com
Evansdale Drive, PO Box 6064
Morgantown, WV 26506-6064                                John Elder
Phone: 304-293-2867 x5401                                Outokumpu
bajura@wvu.edu                                           6100 Phillips Highway
                                                         Jacksonville, FL 32216
Peter Bethell                                            Phone: 904-353-3681
Massey Energy                                            john.elder@outokumpu.com
125 Hurricane Branch Road
Chapmanville, WV 25508                                   Lucy Esdaile
Phone: 304-855-4909                                      Rio Tinto Technology
peter.bethell@MasseyEnergyCo.com                         Phone: +61 39242 3288
                                                         lucy.esdaile@riotinto.com
Bob Bratton
Virginia Tech                                            Greig Freeman
146 Holden Hall                                          CENfuels FPU LTD.
Blacksburg, VA 24061                                     1018 Kanawha Blvd., East
Phone: 540-231-3864                                      Charleston, WV 25301
rbratton@vt.edu                                          Phone: 304-239-2890
                                                         freeman@cenfuelfpu.com




                                                   A-2
                                      DRAFT
                                     October 28, 2002

Maurice Fuerstenau                                  Robert Hollis
University of Nevada, Reno                          Horizon Natural Resources
CHEM & MET ENGINEERING                              104 Candlewick Dr.
MS 388                                              Berra, KY 40403
Reno, NV 89557-0042                                 Phone: 606-922-1094
Phone: 775-784-4310                                 bhollis@horizonnr.com
mcf@unr.edu
                                                    Rick Honaker
Steve Gamble                                        University of Kentucky
IMC Potash Carlsbad, Inc.                           Dept. of Mining Engineering
PO Box 71                                           230 M&MRB
1361 Potash Mines Rd.                               Lexington, KY 40506-0107
Carlsbad, NM 88221                                  Phone: 859-257-1108
Phone: 505-887-2871 x298                            rhonaker@engr.uky.edu
sagamble@imcglobal.com
                                                    John Keating
Ari Geertsema                                       IMC Phosphates
Center for Applied Energy Research                  PO Box 2000
2540 Research Park Drive                            3095 County Road 640 West
Lexington, KY 40511-8410                            Mulberry, FL 33860
Phone: 859-257-0305                                 Phone: 863-428-2500 x6569
ari@caer.uky.edu                                    jmkeating@imcglobal.com

Charles Green                                       Danny King
PO Box 1298,                                        Powell Construction
707 West 7th Street                                 3622 Bristol Highway
Huntington, WV 25714                                Johnson City, TN 37601-1324
richwoodi@aol.com                                   pcc.johnsoncity@worldnet.att.net

Ibrahim Gundiler                                    Pete Knudsen
New Mexico Tech                                     Montana Tech
801 Leroy Place                                     College of Mines & Engineering
Socorro, NM 87801                                   MG 104B
Phone: 505-835-5730                                 Butte, MT 59701
gundiler@gis.nmt.edu                                Phone: 406-496-4395
                                                    pknudsen@mtech.edu
C. Dave Henry
Beard Technology, Inc                               Donald Krastman
355 William Pitt Highway                            National Energy Technology Laboratory
Pittsburgh, PA 15238                                626 Cochrans Mill Road
Phone: 412-826-5396                                 Pittsburgh, PA 15236
cdhconsult@shol.com                                 Phone: 412-386-4720
                                                    krastman@netl.doe.gov
Jeff Herholdt
West Virginia Development Office                    Marc Le Vier
State Capital Complex                               Newmont Mining Corp.
Building 6, Room 645                                Plato Malozemoff Tech Facility
Charleston, WV 25305                                10101 E. Dry Creek Rd.
jherholdt@wvdo.org                                  Englewood, CO 80112
                                                    Phone: 303-708-4424
                                                    mlev4424@corp.newmont.com




                                            A-3
                                         DRAFT
                                        October 28, 2002

 Gerald Luttrell                                       Richard Noceti
Virginia Tech                                          National Energy Technology Laboratory
146 Holden Hall                                        627 Cochrans Mill Road
Blacksburg, VA 24061                                   MS: 922-204
Phone: 540-231-4508                                    Pittsburgh, PA 15236-0941
luttrell@vt.edu                                        Phone: 412-386-5955
                                                       noceti@netl.doe.gov
Carl Maronde
National Energy Technology Laboratory                  Steve Paulson
626 Cochrans Mill Road                                 Ondeo-Nalco
MS: 922-342C                                           Ondeo-Nalco Center
Pittsburgh, PA 15236-0940                              Naperville, IL 60653
Phone: 412-386-6402                                    spaulson@ONDEO-Nalco.com
carl.maronde@netl.doe.gov
                                                       Felicia F. Peng
Charles Maxwell                                        West Virginia University
Phelps Dodge Mining Co.                                Mineral Resources Building
9780 E. Sanchez Rd.                                    PO BOX 6070
Safford, AZ 85546                                      Morgantown, WV 26506-6070
Phone: 928-348-0803                                    Phone: 304-293-7680
cmaxwell@phelpsdodge.com                               ffpeng@mail.wvu.edu

Ken McGough                                            Dennis Phillips
Ondeo-Nalco                                            Daniels Co.
4510 Pennsylvania Ave.                                 Rt. 5 Box 203
Suite F                                                Bluefield, WV 24701
Charleston, WV 25302                                   Phone: 304-327-8161
kmcgough@ONDEO-Nalco.com                               DPhillips@Daniels -WV.com

J.D. Miller                                            James Plumley
University of Utah                                     Arch Coal
Metallurgical Engineering                              RR3
135 S 1450 E Rm 412                                    Box 4440
Salt Lake City, UT 84112-0114                          Danville, WV 25053
Phone: 801-581-5160                                    Phone: 304-792-8215
jdmiller@mines.utah.edu                                jplumley@archcoal.com

Bob Moorhead                                           Tommy Prater
Krebs Engineering                                      Teco Coal
611 S. Walnut St.                                      Phone: 606-835-3239
Blairsville, PA 15717                                  tlprater@tecoenergy.com
Phone: 724-459-9158
rmoorhead@krebs.com                                    William Raney
                                                       West Virginia Coal Association
Charles Murphy                                         PO Box 3923
Riverton Coal                                          Charleston, WV 25339
Rockspring Plant                                       Phone: 304-346-5318
PO Box 340                                             braney@wvcoal.com
Phone: 304-849-3730
                                                       Richard Robinson
                                                       Alliance Coal, LLC
                                                       771 Corporate Drive
                                                       Ste. 1000
                                                       Lexington, KY 40504
                                                       Phone: 859-224-7233
                                                       richard.robinson@arlp.com



                                               A-4
                               DRAFT
                              October 28, 2002

Frank Saus                                   Philip Thompson
West Virginia University                     Dawson Metallurgical Labs
Evansdale Drive                              2030 N. Redwood Rd.
PO Box 6064                                  Suite 70
Morgantown, WV 26506-6064                    Salt Lake City, UT 84116
Phone: 304-293-7318                          Phone: 801-596-0430
Frank.Saus@mail.wvu.edu                      dmlmetlab@aol.com

Paul Slater                                  Tom Toscano
1113 D Jefferson Road Plaza                  Cytec Industries Inc
South Charleston, WV 25309                   Phone: 304-744-3454
                                             tom_toscano@gm.cytec.com
Richard Snoby
Allmineral LCC                               Larry Watters
1360 Union Hill Rd.                          Sedgman
Alpharetta, GA 30004                         2090 Greentree Road
Phone: 770-410-0220                          Pittsburgh, PA 15220
allmineral@aol.com                           lwatters@sedgman.com

Richard Sweigard                             Asa Weber
University of Kentucky                       EIMCO
Dept. of Mining Engineering                  414 West 300 South
230 M&MRB                                    Salt Lake City, UT 84110-0300
Lexington, KY 40506-0107                     asa.weber@eimcoprocess.com
Phone: 859-257-1173
rsweigar@engr.uky.edu                        Dan Yanchak
                                             Consol Energy
Michael Taylor                               PO Box 355
Hatch Engineering                            172 Rt. 519
1600 West Carson St.                         Eighty Four, PA 15330
Gateway View Plaza                           Phone: 724-206-2037
Pittsburgh, PA 15219                         danyanchak@consolenergy.com
Phone: 412-497-2117
mtaylor@hatch.ca                             Roe-Hoan Yoon
                                             Virginia Tech
Richard Terry                                146 Holden Hall
Sedgman                                      Blacksburg, VA 24061
3661 Robert C. Byrd Dr.                      Phone: 540-321-7056
Beckley, WV 25801                            ryoon@vt.edu
Phone: 304-256-0031
rterry@sedgman.com                           Joe Zachwieja
                                             Akzo Nobel
                                             300 South Riverside Plaza
                                             Chicago, IL 60606-6697
                                             Phone: 312-906-7016
                                             joseph.zachwieje@akzonobel.com




                                     A-5
      DRAFT
    October 28, 2002




     APPENDIX B


TERMS AND DEFINITIONS




           B-1
                                          DRAFT
                                       October 28, 2002
Appendix B

                             TERMS AND DEFINITIONS

1. Physical Separation

  Ores and coal are upgraded on the basis of their physical properties such as particle size,
  specific gravity, electrical conductivity, magnetic susceptibility, optical properties, surface
  chemical properties, etc. An important factor affecting various physical separation processes is
  particle size. Each process has a range of particle sizes where it is most effective. In general,
  the separation efficiencies decrease with decreasing particle size, which is the biggest
  limitation of the physical separation processes.

A. Size-Size Separation

    Many of the solid-solid separation processes are effective over a narrow particle size range.
    Therefore, size-size separation is often practiced prior to solid-solid separation to maximize
    the efficiency of the latter. Size-size separation is also practiced to increase the value of the
    final product. There are two ways of achieving size-size separation:

        Screening

       Screens are used to separate relatively coarse particles according to their sizes, as the
       efficiency of screening deteriorates rapidly with decreasing particle size. Fine screens
       are fragile and wear quickly. Furthermore, fine screens are easily blinded and suffer from
       low throughput and low efficiency. Therefore, screening is limited in general to materials
       of 250 µm in size or above.

        Classification

       Classification is a method of separating particulate materials according to the velocities of
       the particles moving in a fluid, usually in water or air. In general, wet -classification is
       more efficient than air classification. The efficiency of classification depends not only on
       particle size but also on specific gravity (S.G.) and shape. Therefore, classifiers are less
       efficient than screens but are of higher capacity.

B. Solid-Solid Separation

   One type of particulate materials is separated from another for value enhancement or to meet
   environmental requirements. The separation is affected by exploiting differences in specific
   gravity, magnetic susceptibility, electrical conductivity, surface property, dielectric property,
   etc.

        Flotation

       Particulate materials dispersed in water flow through a tank, in which air bubbles are
       introduced. The air bubbles selectively collect the particles that are hydrophobic, and exit
       the tank by levitation, while leaving hydrophilic particles behind. Thus, the separation is
       based on rendering a selected material hydrophobic, although some are naturally
       hydrophobic. Various reagents are used to hydrophobize different materials. Flotation is
       effective in the particle size range of approximately 10 to 100 µm for minerals and 44 to
       500 µm for coal. It experiences difficulties with coarse and ultra fine particles.




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                                      October 28, 2002

       Selective Flocculation

       Ultra fine particles are dispersed in water with the aid of peptizing agents. An organic
       flocculant is then added to enlarge the size of the selected constituent, so that it can
       settle to the bottom of a settling vessel, while others are left in suspension. Thus, the
       separation is based on causing a flocculant to selectively adsorb on the surface of a
       selected particulate material. The process is effective with ultra fine particles, with which
       flotation is ineffective. In general, it suffers from low recovery due to entrapment of
       unwanted particles in the settled zone.

       Magnetic/Electrostatic Separation

       Magnetic particles are separated from non-magnetic particles in a magnetic field. Its
       efficiency decreases with decreasing magnetic susceptibility and particle size. Cryogenic
       high-intensity and high-gradient magnetic separators are used to overcome these
       problems. Electrostatic separators are designed to separate charged particles in an
       electric field. Particles can be charged by induction, conduction, or triboelectrification
       mechanism.

       Gravity Separation

       Particles are separated according to their velocities in a fluid, which in turn are
       determined by the specific gravities (S.G.) of the particles involved. For large particles,
       gravitational field can be used to create differences in settling velocities. For fine
       particles, high-G forces may be necessary to achieve effective separation. Since the
       settling velocities are also affected by the size of the particles involved, gravity separation
       is most effective with narrowly sized particles.

C. Solid-Liquid Separation

   Most solid-solid separations occur in water. The products are dewatered to minimize shipping
   costs, improve handleability, and increase market values. The solid-liquid separation
   processes used in the minerals and coal industries include the following:

       Thickening

       Particulate materials are allowed to settle by gravity in a large settling tank. The
       supernatant water overflows into a launder, while the thickened slurry is removed at the
       bottom. Lamella thickeners are used to decrease settling distances and increase settling
       area, thereby decreasing the equipment size. Paste thickeners are designed to produce
       high percent of solid underflows. To increase settling rate, particle sizes are enlarged by
       adding various flocculants and coagulants.

       Centrifugation

       High-G forces are used to greatly increase the settling rates and obtain higher percent of
       solid materials. Solid bowl and screen bowl centrifuges are widely used in industry. The
       latter produces lower moisture products than the former by virtue of the loss of finer
       particles. Owing to their higher settling rates, centrifugal dewatering devices are capable
       of handling large quantities of materials.

       Filtration

       Filtration is a process of removing water by retaining a particulate material on a medium.
       Its driving force is the pressure drop across the medium and the filter cake formed on the
       medium, and the rate of filtration depends on various physical and chemical parameters.



                                              B-3
                                DRAFT
                              October 28, 2002

For relatively coarse particles, vacuum filters are used. For materials containing large
amounts of ultra fine particles, pressure filters are more effective. Various chemicals are
used to facilitate dewatering.

Drying

Drying refers to the method of dewatering materials by thermal evaporation. Because of
the high latent heat of evaporation of water, it is inherently a costly process. When
mechanical dewatering methods cannot reduce the moisture to desired levels, thermal
drying is often the only option.




                                      B-4
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                                      October 28, 2002
2. CHEMICAL BIOLOGICAL SEPARATION

A. Leaching

    The relatively low temperature aqueous phase dissolution of a particular mineral component,
    usually the valuable component, from insoluble material. Leaching is an important step in
    hydrometallurgical processes and can be classified, according to the extent of ore
    pretreatment, into in-situ mining, heap leaching, and concentrate leaching. In addition,
    leaching systems can be classified into:

       Chemical

       Chemical leaching involves dissolution reactions in the absence of bacteria that is
       achieved by traditional oxidation/reduction reactions, neutralization reactions, and/or
       complex reactions.

       Biological

       Biological leaching involves dissolution in the presence of bacteria, which facilitates the
       leaching reaction.

B. Solution Concentration and/or Purification

   Frequently the leach solution in hydrometallurgical processes is treated to increase the
   concentration of the valuable component and/or to remove impurities prior to product
   recovery.

       Solvent Extraction

       Solvent extraction is the selective transfer of a specific component from the aqueous
       leach solution into an immiscible organic phase, from which that compound is
       subsequently stripped off into a purified and concentrated aqueous phase.

       Ion Exchange

       Ion exchange is the selective exchange between an ionic component in a leach solution
       and an ion contained in a porous polymeric resin bead. Stripping of the loaded resin then
       produces a purified and concentrated aqueous phase from which the desired product can
       be recovered.

       Precipitation/Cementation

       In the case of precipitation, generally the impurity in the leach solution is precipitated by
       chemical reaction with an appropriate reagent or by adjusting the temperature/pressure of
       the system. The particulate phase is then removed prior to product recovery from
       solution. Alternatively, the valuable component can be removed as an impure material
       and subsequently refined for product recovery.

       Adsorption

       In some regard, adsorption is similar to ion exchange in the sense that the reactant is
       immobilized and a dissolved component of the leach solution, usually the valuable
       component, is removed from solution by reaction with surface sites.




                                                B-5
                                       DRAFT
                                     October 28, 2002

C. Product Recovery

  The final step in any hydrometallurgical process is product recovery. Product recovery
  generally involves removal of the product from the concentrated and purified leach solution.
  Invariably this will be a solid material recovered by electrolysis, cementation, precipitation,
  crystallization, etc.

      Electrolysis

      In the case of electrolysis, the product is recovered electrolytically as a deposit that forms
      on the electrode.

      Precipitation

      Product recovery can be achieved by precipitation of a desired component with an
      appropriate reagent.

      Crystallization

      Frequently, crystallization is used in the salt industries, which includes potash, borax,
      trona, etc., for product recovery. In this case, recovery is achieved by changes in
      temperature and/or pressure to cause crystallization to occur from saturated brine
      solutions.




                                             B-6
                                     DRAFT
                                    October 28, 2002

3. ENVIRONMENTAL CONTROL

A. Emission Control

   The U.S. mining industry is regulated by various environmental regulations that are in-place
   or forthcoming. The 1990 Clean Air Act Amendment (CAAA), for example, limits emissions
   of acid-rain precursors and hazardous air pollutant precursors (HAPPS) from coal-burning
   power plants. Environmental Protection Agency (EPA) will soon promulgate mercury
   emission standard, which will be another serious constraints under which the coal industry
   must operate.

       Sulfur

      The CAAA limits sulfur dioxide (SO2) emissions from coal-burning power plants to 10
      million tons per year, while the United States will continue to rely on coal for meeting
      increased electricity demand. While scrubbers and fuel switching may be used to
      minimize SO2 emissions, advancement in pre-combustion coal cleaning technologies can
      remove both inorganic and organic sulfur from coal.

       Trace Elements

      The 1990 CAAA lists various trace elements present in coal as HAPPS. Much of the
      trace elements such as mercury are associated in the mineral matter present in coal.
      While the utility industry is preparing to comply with the new regulations by using post-
      combustion scrubbers, improved pre-combustion coal cleaning technologies may also be
      used to remove trace elements from coal.

       Fugitive Dusts

      At various stages of producing, transporting and storing coal, ultra fine particles become
      airborne, creating public concerns and affecting worker health.

B. Remining

   Both coal and mineral industries generate significant amounts of wastes due to the lack of
   efficient separation technologies. As new and advanced technologies emerge in time, it may
   become economically feasible to recover the valuable components that have been discarded
   previously by remining.

       Mining

      The materials containing significant amounts of valuable components are excavated from
      waste piles and impoundments using appropriate mining method and moved to a facility
      where the valuable components are separated from valueless. Providing a consistent
      feed stream to the separation facility in the most economical and environmentally
      acceptable manner is important in remining operations.

       Separation

      Valuable components are separated from valueless by using various physical separation
      processes that exploit the differences in physical and surface chemical properties.
      Chemical/biological methods may also be used for the separation.




                                            B-7
                                     DRAFT
                                    October 28, 2002

      Disposal

      The reject materials generated from the waste recovery operations are disposed of,
      sometimes back to the waste pile or to the impoundments where they originated, or other
      times back to old mine workings. In the former, care is taken not to impair remining
      operations. In the latter, care is taken so that the refuse materials do not contain
      hazardous elements that can potentially contaminate ground water.

C. Waste Disposal

   The extraction, beneficiation, and utilization of mineral commodities generally produce some
   amount of waste that must be disposed of in an environmentally acceptable manner. The
   waste can consist of both solid and liquid components with a wide range of properties
   depending on the types of minerals and processes involved.

      Acid Mine Drainage

      Leachate resulting from the oxidation of sulfur associated with waste or from exposed
      pyrite in old workings.

      Impoundment

      A permanent storage structure for either coal or mineral processing waste including an
      impounding structure and a basin. The waste consists of a mixture of water and fine
      particles, typically less than 100 mesh.

      Fly Ash

      Ultra fine byproduct of coal combustion captured from the exhaust stream. It is generally
      alkaline in nature with strong pozolanic qualities and may contain significant amounts of
      unburned carbon.

      Recycle Water

      Water decanted from clarification processes that is reused in mining or mineral
      processing applications.




                                           B-8
        DRAFT
      October 28, 2002




      APPENDIX C


CAST ORGANIZATION CHART




             C-1
                       DRAFT
                     October 28, 2002




                                            R&D Activities
                                                  at
                             Center for Advanced Separation Technologies




                                                   Director
                                                 Support Staff

                                 Technical                         Advisory
                                 Committee                          Board


  Physical                        Chemical                   Environmental            Industrial
 Separation                      Separation                     Control               Program


Size-Size                       Leaching                         Emission                  Industry
Separation                                                       Control                   Affiliates

                                                                                         Cooperative
    Screening                       Chemical                         Sulfur                 R&D
    Classification                  Biological                       Trace Elements
Solid-Solid                     Solution Concentration               Fugitive Dust
Separation                      and/or Purification              Remining


    Flotation                       Solvent Extraction
    Selective Flocculation          Ion-Exchange                     Mining
    Magnetic/electrostatic          Precipitation                    Separation
    Gravity Separation              Adsorption                       Disposal
Solid-Liquid                    Product Recovery                 Waste Disposal
Separation


    Thickening                      Electrolysis                     AMD
    Centrifugation                  Cementation                      Impoundment
    Filtration                      Precipitation                    Fly Ash
    Drying                          Crystallization                  Recycle Water




                                                      C-2

								
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