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					Case study – ventilation planning for
     Bog Zone, Lisheen Mine
         Kristen Hopperstead
 Ventilation in mine design
  process                        Secondary Egress
   o Feasibility                   o Impacts shaft design
                                 Implementation
   o Design changes
                                   o staged
   o Quantify amount of air          implementation
     required                    Conclusions
 Impact of larger mobile
  equipment fleet
   o Auxiliary circuit
   o Main ventilation circuit

Introduction
Location
 Cool, wet climate
 352 Employees from 14
  countries
 Underground Zinc and
  Lead Mine
 High grade
 Mine life 1999 - 2014
 1.6 million tonne
  annual production rate
 Strict Environmental
  Conditions
Lisheen’s Vital Statistics
     Main
     North
                                           Derryville
                                                           Bog Zone
                                                 haulage




                                                                      N

                                 Crusher
                              FAS & Alimak
             Main Zone


Primary Ventilation Circuit
 The Bog Zone is a new addition to the Lisheen
  Mine which extends the underground footprint
  eastwards.

 The feasibility study completed in 2003

 Planning permission received from North Tipperary
  County Council a year later.

 Developed from 2004-2007

 Provides 43% of future metal for Lisheen
Bog Zone
           Scale                   Bog Central
 N         100m


                   Bog West
     VR6
                                                                Bog
haulage
                                                                East
                                                         VR8
                                      VR7
                                    Lisheen Property Boundary




 Mine Planning & Ventilation – Feasibility Stage 2003
Bog West Stopes




Bog East Upper Lens


                        Bog Central




  Bog East Lower Lens
                      Mining Method            m3/s/Mtpa
               Large open stopes >0.5 Mtpa        160

               Small open stopes <0.5 Mtpa        240

                      Room and Pillar             200

              Scale
 N                                      Bog Central
              100m



VR6        Bog West

                                                                 Bog
haulage
                                                                 East
                                         VR7               VR8


 Mine Planning & Ventilation - Bog Zone Mine Design Change 2006
 Lisheen standard 0.04 m³/s per kW of rated engine
  power
 Average heading requires 24 m³/s
   o based on a 250 kW loader and a 40 tonne (350 kW)
     truck
   o standard auxiliary fans employed meet this
     requirement
 Loading 50 tonne (450 kW) trucks with 350 kW loaders
   o target delivery airflow of 34 m³/s
 Larger auxiliary fans required

New Auxiliary Fan Sizes 2007
 New standard for the Bog Zone auxiliary fans

 Determine the overall amount of air needed based on:
  o the total number of working headings in Bog Zone
  o the size of the fleet and crew
  o the overall mining schedule
  o increase amount of air on haulage

 Amount of air needed is 200m3/s

 40% increase of total airflow required to mine Bog
  Zone
Reevaluate Total Volume Flow
 VR6 and VR7 have
  been raisebored
   o Contractor to return
     in four months to
     complete VR8
 Lisheen does not have
  a current ventilation
  model
   o Consultant hired to
     perform model
     simulations

OMG! 40% More Air Required!!
                                VR8 escapeway
                                Planned 3m diameter
                                100 m3/s and
                                 ladderway
                                Revise plan to 4m
                                 diameter




External Review and Modeling
                  BZ haulage airflow direction
                  Total volume through VR7
                  Operating Cost
                     o minimize electrical power
                         cost – US $1.1 million/yr
               Scale
                         capped by electrical grid
         N     100m               Bog Central


                Bog West
 Jet-
thrust   VR6
                                                            Bog
haulage                                                     East
                                   VR7                VR8

  External Review and Modeling
                 N




External Review and Modeling
    In-house waste development - November 2004
    Auxiliary force ventilation
    In house waste development 50m a month
      o Bog Zone full production by September 2007
                 Scale
                  100m
     N


                                      Aux. exhaust fan




     Aux. force fan




Staged Implementation
     Contractor start development August 2006
     November 2006 Raiseboring of VR6 complete
     Auxiliary vent move up
N


VR6




                                                  Scale
                                                  100m


Staged Implementation – Accelerated Development
        Underground access VR7 complete
         February 2007
        April 2007 raiseboring VR7 finished
        Auxiliary vent move up
          o In-line booster fan
                 Scale
 N               100m

                                                    In-line
                                                  booster fan
VR6



                                            VR7

Staged Implementation – Accelerated Development
  Underground access VR8 complete July 2007
  Raiseboring VR8 finished September 2007
  Raiseboring VR7A complete October 2007
              Scale
 N            100m




VR6




                             VR7A    VR7          VR8



Staged Implementation – Accelerated Development
 Quotation
 Operating Cost
   o minimize electrical power
       cost – a single kW US $1400/ yr
       capped by electrical grid
 Procurement Issues
 Installation planned August 2008
 Staged Implementation – Main Fan
 Cost benefit analysis of
  ladderway vs
  refurbished Alimak
 December 2007 VR8
  supported
 Refurbished Alimak to
  be installed end of this
  month



Staged Implementation – Secondary Egress
 Ventilation plans must be reevaluated and changed
  as conditions evolve.
   o realize a better distribution of airflow, optimized
     secondary escape way, reduced contaminants,
     and reduced total power requirements.

 Supply chain problems can greatly affect timeline.

 Computerized ventilation modeling and planning
  for staged implementation should never be
  underestimated.
Conclusions
Thank you

				
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