Docstoc

Mineral Deposits

Document Sample
Mineral Deposits Powered By Docstoc
					                                                                  MINERAL DEPOSITS




                                       CHAPTER I
                                            ISI


I. 1. Preliminary


Minerals history proposed by Charpentier (1778-1799) and Gerhard (1781). Charpentier
expressed vein-vein formed by the alteration in the rock side, the existence of a graded
vein rock side. While Gerhard stated vein-vein formed at an opening by the minerals
terleachingkan the rock side. So they conclude a theory of 'lateral secretion', the mineral
content of a deposit that into a sludge ore from rocks adjacent side by water.


Then Hutton (1788 & 1795) states that the igneous rocks and mineral ores from magma
and placed in a liquid state (liquid) to be present condition. Other Opinions also stated
that the deposition of ore coming from the magma is also supported by the Joseph
Brunner (1801) and Scipione Breislak (1811), the theory of magma differentiation and
magma segregation. then Spurr (1933) refine the theory that the types of minerals that
are formed depending on the type of rock origin. Theories they will continue to grow,
until Waldemar Lindgren (1907, 1913 and 1922) produced a classification of sediments
based on its genetic processes.


Sediment Classification Minerals:


1. Based on the similarity of characteristics and descriptions.
2. Equation genesis and location of the deposition process.
3. Conformity theories and depositional environment.
4. Made as simple as possible so easy in implementation and flexible.
5. Until now, only the sedimentary deposition and deposition associated with igneous
rocks can be distinguished.



By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                         1
                                                                   MINERAL DEPOSITS




I.2. Definition


Is one pembentukkannya sediment genesis occurred outside surface is affected by
external factors and is derived from the debris deposition before both magmatism and
deposition in hydrothermal and experience back through the process of weathering,
transportation, sorting (sorting), and the concentration (enrichment). Deposition mineral
is an accumulation of minerals in the form of mineral or rock that is in the earth's crust
formed by the particular geological and economic value. According to Hoover and
Hoover (translator of De re Metallica), Agricola grouping based on two basic principles,
namely:


secondary     precipitate    formed,    so     younger      than   the    parent    rock.
precipitate       formed    by   circulation    of    the     solution    in    channels.
sediment surface is divided into 2, namely:


1. Sediment sedimentary (Placer)


Placer deposits are formed (concentrated) by mechanical processes, especially during the
heavy minerals (heavy minerals), which has a resistance (resistance) against weathering.
Placer sediment divided into sediment residual placer, alluvial placer sediments
(stream), sediment beach (beach placer) and sediment offshore (offshore placer). Placer
Residual sediment is sediment that forms in placer origin of rocks that have faragmen
lighter and easily dissolve if tertransportasi (heavy mineral concentrate), as well as in
morphology or topography is relatively flat. Whereas when you're on the sloping
topography called eluvial placer sediment. Alluvial placer sediment deposition is a very
important type of gold and diamonds. Grain size fractions in heavy minerals are
relatively more subtle than minor minerals. Heavy minerals will be concentrated in
locations where there is a disruption of the flow of energy or penggurangan like the



By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                        2
                                                                   MINERAL DEPOSITS




holes of the river or waterfall, or on a natural riffle or the river meanders.
Placer minerals in sediments. An iron sands deposits in addition to

minerals containing iron ore is made possible in association with the main minerals
containing Fe others are: pyrite (FeS2), markasit (FeS), pyrrhotite (Fe1-XS), chamosit
[Fe2Al2 SiO5 (OH) 4], ilmenite (FeTiO3) , wolframite [(Fe, Mn) WO4], chromite
(FeCr2O4), or minerals are also non-Fe can provide value added services such as: rutile
(TiO2), kasiterit (SnO2), monazite [Ce, La, Nd, Th (PO4, SiO4)], diamonds, gold (Au),
platinum (pt), xenotime (YPO4), zircon (ZrSiO4) and others.

Factors that influence the formation of this sediment is:
 Mechanical Weathering, which is resistant to mechanical weathering (no physical
damage).
 Have Differences Gravity and gravity concentration, which allows the deposition back
to achieve economic concentrations.
 Mechanical Transport (water, wind, and sea).
 Environment deposition.


1. Placer residual. Particles of minerals / ore deposits accumulate forming directly over
the source rocks (eg, veins containing gold or kasiterit) who have experienced vandalism
/ destruction of chemical and materials separated from the lighter rock. Types of
deposits is only formed in a nearly flat surface, which can also be found inside the
minerals that are resistant lightweight chemical reactions (eg, beryl).
2. Placer eluvial. Particles of minerals / ore deposits forming this type deposited on the
hillside of a source rock. In some areas found eluvial placer with materials economically
valuable constituent accumulated in pockets (pockets) bedrock surface.
3. Placer river or alluvial. This type is most important particularly with regard to gold
ore is generally associated with iron ore, where the layer configuration and particle
density of mineral / ore to be important factors in the formation. It is known that the
heavy mineral fraction

By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                             3
                                                                    MINERAL DEPOSITS




these deposits are smaller than light mineral fraction, with respect: First, the heavy
minerals in the source rock (frozen and metamorphic) are formed in a smaller size than
the main minerals forming rocks. Second, sorting and composition of sediment
deposition is controlled by the density and particle size (hydraulic ratio).


A. Placer beach. Deposits are formed along the shoreline by the concentration of sea
water waves and currents along the coast. The waves tossed the particles forming
deposits to the beach where the water is returned with lightweight materials to be
separated from heavy mineral. Increase in size and weight of the particles to be
deposited / concentrated on the coast, and then accumulate as clear boundaries and form
a layer. Perlapisan shows the reverse order of the size and weight of particles, wherein
the base layer of fines and / or rich in heavy minerals and to the top gradually becomes
more abusive and / or low in heavy minerals.


B. Placer beach (beach placer) occur at different topographic conditions caused by
changes in sea level, where the optimum separation of heavy mineral zones are in the
tidal zone of an open coast. Particle concentration minerals / ore is also possible on the
results terrace formation of ocean waves. The most important minerals contained in
mineral deposit types are: magnetite, ilmenite, gold, kasiterit, diamonds, monazite,
rutile, xenotime and zircon.


2. Deposition Laterik.


Have an example in the form of deposits of nickel laterite and bauxite deposits. Factors
affecting sediment laterik are:


 Mechanical and Chemical Weathering
 Has the mobility difference



By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                        4
                                                               MINERAL DEPOSITS




 Experienced Leaching (concentration enrichment)
 The concentration of residual and Supergene enrichment
2. alluvial deposits


Alluvial deposits of sediment deposition process is influenced by water, especially by
the river. Mineral composition of an alluvial mineral deposits are usually more severe,
including many minerals and precious metals.




                                Laterit Deposit




                            Placer Deposit




By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                     5
                                                               MINERAL DEPOSITS




I. I. 3. Goals and Purpose


       To determine the types of sediment surfaces that affect the process of formation
of minerals present in minerals. As a reference in the learning process of mineral
deposition.




By : GUMIRLANG SUCAHYO // gilang052@gmail.com
                                                                                     6

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:53
posted:10/6/2012
language:English
pages:6
Description: Science information