Geology Rocks!!!

Evolutionary Trends in Trilobites

2012-10-04T06:25:00.003-07:00

Gold Deposit Statistics of India

2012-09-28T05:06:00.002-07:00

Gypsum Deposit Statistics of India

2012-09-28T04:03:00.002-07:00

Copper Deposit Statistics of India

2012-09-28T03:53:00.001-07:00

Bauxite Deposit Statistics of India

2012-09-28T03:33:00.001-07:00

Groundwater Quality : WHO amounts for admissible impurities

2012-09-28T03:07:00.000-07:00

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
	ug/L (unless otherwise indicated)
Acenaphthene	80
Acenaphthylene	200
Acetone	6 mg/L
Acrylamide	0.008
Anthracene	2 mg/L
Arsenic	10
Atrazine and chlorotriazine metabolites	3
Barium	700
Benzene	1
Benzo(a)anthracene	0.05
Benzo(b)fluoranthene	0.05
Benzo(k)fluoranthene	0.5
Benzoic acid	30 mg/L
Benzo(g,h,i)perylene	200
Benzo(a)pyrene	0.005
Bis(chloroethyl)ether	0.03
Bis(2-ethylhexyl)phthalate (di(2-ethylhexyl)phthalate)	3
Boron	700
Bromodichloromethane	0.6
Bromoform (tribromomethane)	4
n-Butylbenzene	70
sec-Butylbenzene	70
tert-Butylbenzene	70
Butylbenzyl phthalate	1 mg/L
Cadmium	2
Caprolactam	4 mg/L

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
Carbofuran	40
Carbon disulfide	700
Carbon tetrachloride	0.3
Chlordane	0.1
Chloride	250 mg/L
Chlorobenzene	50
Chloroethane	3,000
Chloroform (trichloromethane)	70
Chloromethane (methyl chloride)	3
2-Chlorophenol	0.4
2-Chlorotoluene (o-chlorotoluene)	100
Chromium	10
Chrysene	5
Coliform organisms, Total	1 per 100 mL
Color	15 color units
Copper	1 mg/L
Cyanide, free	70
2,4-D	70
DDD	0.1
DDT	0.1
Dibenzo(a,h)anthracene	0.005
Dibromochloromethane	0.4
1,2-Dibromo-3-chloropropane	0.04
Dibutyl phthalate (di-n-butyl phthalate)	700
1,2-Dichlorobenzene (orthodichlorobenzene)	20
1,3-Dichlorobenzene (metadichlorobenzene)	200
1,4-Dichlorobenzene (paradichlorobenzene)	6

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
Dichlorodifluoromethane (Freon-12; Halon)	1 mg/L
1,1-Dichloroethane	6
1,2-Dichloroethane (ethylene dichloride)	0.4
1,2-Dichloroethene (cis)	70
1,2-Dichloroethene (trans)	100
1,1-Dichloroethylene (vinylidene chloride)	7
1,2-Dichloropropane	0.6
1,3-Dichloropropene (cis and trans isomers)	0.4
Dieldrin	0.002
Diethylphthalate	6 mg/L
2,4-Dimethylphenol (m-xylenol)	100
Di-n-octyl phthalate	100
1,4-Dioxane (p-dioxane)	3
Dioxin (2,3,7,8-TCDD)	0.0002 ng/L
1,1-Diphenyl (1,1-biphenyl)	400
Dissolved solids, Total	500 mg/L
Disulfoton	0.3
Diundecyl phthalate (Santicizer 711)	100
Endosulfan (includes technical mixture of alpha and beta isomers)	40
Endrin, total (includes endrin, endrin aldehyde, and endrin ketone)	2
Epichlorohydrin	4
Ethyl acetate	3 mg/L
Ethylbenzene	600
Ethylene dibromide (1,2-dibromoethane)	0.02
Ethylene glycol	10 mg/L
Fluoranthene	300

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
Fluorene	300
Fluoride	2 mg/L
Foaming agents	500
Formaldehyde	600
Gross alpha (adjusted) particle activity (excludes radium-226 and uranium)	15 pCi/L
Heptachlor	0.008
Heptachlor epoxide	0.004
Heptane	400
Hexachlorobenzene (perchlorobenzene)	0.02
Hexachlorobutadiene	0.4
Hexachlorocyclohexane isomers (technical grade)	0.02
n-Hexane	400
Indeno(1,2,3-cd)pyrene	0.05
Iron	300
Isophorone	40
Isopropylbenzene	70
Isopropyl ether	70
Lead	15
Lindane (gamma hexachlorocyclohexane)	0.03
Manganese	50
Mercury	1
Methanol	4 mg/L
Methoxychlor	40
Methylene chloride dichloromethane)	5
Methyl ethyl ketone (2-butanone)	4 mg/L
2-Methylnaphthalene	30
3-Methylphenol (m-cresol)	400

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
4-Methylphenol (p-cresol)	40
Methyl tert-butyl ether MTBE)	20
Naphthalene	6
Nickel	100
Nitrate (as N)	10 mg/L
Nitrite (as N)	1 mg/L
N-nitrosodimethylamine	0.0007
Oxamyl	200
Pentachlorophenol	0.3
Petroleum aliphatic carbon fraction class C₅-C₈	400
Petroleum aliphatic carbon fraction class C₉-Ci₈	700
Petroleum aliphatic carbon fraction class Ci₉-C₃₆	10 mg/L
Petroleum aromatics carbon fraction class C₉-C₂₂	200
pH	6.5 - 8.5
Phenanthrene	200
Phenol	30
Phorate	1
n-Propylbenzene	70
Pyrene	200
Selenium	20
Silver	20
Simazine	4
Styrene	70
Sulfate	250 mg/L
1, 1,2,2- Tetrachloroethane	0.2
Tetrachloroethylene (perchloroethylene; PCE)	0.7
2,3,4,6-Tetrachlorophenol	200

Substance	15A NCAC 2L .0202 Groundwater Standard (Effective January 1, 2010)
Toluene	600
Toxaphene	0.03
2,4,5- TP (Silvex)	50
1,2,4- Trichlorobenzene	70
1,1,1- Trichloroethane	200
Trichloroethylene	3
Trichlorofluoromethane	2 mg/L
1,2,3- Trichloropropane	0.005
1,2,4- Trimethylbenzene	400
1,3,5- Trimethylbenzene	400
1, 1,2-Trichloro-1,2,2-trifluoroethane (CFC-113)	200 mg/L
Vinyl chloride	0.03
Xylenes (o-, m-, p-)	500
Zinc	1 mg/L

Apatite and Rock Phosphate

2012-09-24T22:14:00.003-07:00

Apatite is the most abundant crystalline phosphate mineral found as an accessory mineral in practically all kinds of igneous rocks. Sometimes, it is concentrated in pegmatites, metallic veins and magmatic deposits. It also occurs in metamorphic rocks and as a secondary mineral in phosphatic rocks of sedimentary origin. Fluorapatite Ca5(PO4)3F is the most common variety of apatite and also a secondary source of fluorine. Collophane is apparently a cryptocrystalline or amorphous calcium phosphate complex. Rock phosphates or phosphorites are sedimentary phosphatic deposits comprising fine-grained mixture of various calcium phosphates, most important being hydroxyl-apatite, carbonate-apatite, fluor-apatite and their solid solutions. About 80% phosphate production in the world is derived from phosphate rocks (phosphorite) containing one or more phosphatic minerals, usually calcium phosphate of sufficient purity and quantity to permit its use directly or after concentration in manufacturing commercial products. Phosphate rock is also the source of byproduct fluorine. Apatite & rock phosphate containing 3 to 4% CaF2 are useful for recovery of fluorite. It is recovered as by-product Hydrofluoro silicic acid obtained from phosphoric acid plants during processing of rock phosphate. Phosphate rock also contains significant amount of uranium. Phosphate rocks are considered as the most important secondary resource of uranium.

Applications of Darcy's Law

2012-09-24T21:56:00.000-07:00

Indian Plate and its Seismicity

2012-09-23T04:04:00.000-07:00

The Aravalli Supergroup

2012-09-20T06:00:00.000-07:00

Indian Craton

2012-09-15T23:00:00.004-07:00

The oldest dated rocks (---3.4 Ga)lie in the Aravalli, Singhbhum and Dharwar cratons of northern and southern India. A major crust-forming event (Orogeny I), culminating at 3.0 Ga, stabilized the Peninsular Gneiss of south-central India, which forms basement to both the late Archean Dharwar supracrustal belts and platform sediments of the South Indian Highlands (Granulite Domain). The Archean-Proterozoic boundary, at 2.5 Ga, is marked by another major crust-forming event (Orogeny II) characterized by high grade metamorphism (charnockites), to consolidate the Dravidian Shield (southern India).

Early Proterozoic activities included volcanism sedimentation in the Aravalli and Singhbhum areas, initiation of Cuddapah Basin accumulation (2.0Ga) and terminal-era activities at 1.65Ga involving Singhbhum (Copper Belt) Thrust and

Eastern Ghats Orogeny (Orogeny III) to form a coherent Indian Craton.

Later Proterozoic (Riphean) time involved localized basinal rifting with platform accumulations in major continental repositories including Vindhyan and Cuddapah basins. The Eastern Ghats Belt experienced high grade metamorphism at 1.1- 1.0 Ga, the possible time of its accretion to the Indian Shield. The classification scheme for post 1.65 Ga time comprises early, mid, and late Riphean terminating with the Vendian (to 0.57 Ga).

Summary chrono-stratigraphic development of Precambrian crust of the Indian Craton. Salient crustal units and events are arranged in relation to internal orogenies and resulting tectonic cycles.

Diagnostic Properties of Ore Minerals under Microscope :- Bismuth

2012-09-14T19:10:00.004-07:00

Chemical Configuration: Bi
Crystal System: Trigonal
Color: white, brilliant creamy
Geologic Environment: hydrothermal Co-Ni-Ag-Sn ores, pegmatites, topaz-Sn-W veins

Reflectance [%]: 65.35 - 66.65
Anisotropy: distinct
Pleochroism : feeble

Descriptions

A: Skeletal bismuth (pinkish white, strongly scratched) in safflorite (white); Nic. //
B: Twin lamellae in native bismuth (yellowish to blue grey anisotropy); Nic. +
C: Twinned skeletal bismuth (distinct anisotropy along twin suture) in safflorite (brown to blue
anisotropy); Nic. +

Diagnostic Properties of Ore Minerals under Microscope :- Arsenopyrite

2012-09-11T19:21:00.000-07:00

Chemical Configuration: FeAsS
Crystal System: Monoclinic
Color: white, faint yellow tint
Geologic Environment: high temperature veins, pegmatites, contact metamorphic rocks

Reflectance [%]: 50.36 - 51.21
(51.15 - 53.6 cobaltian)
Anisotropy: strong, red-violet
Pleochroism :weak, white with bluish tint to faint reddish yellow

Descriptions

A: Euhedral arsenopyrite (rhombohedral to skeletal, white) in myrmekitic intergrowths of falkmanite
(greenish) and galena (light grey); Nic. //
B: Euhedral arsenopyrite (white) next to large pyrite crystals (slightly yellow) and pyrrhotite
(cream with brownish tint), carbonate matrix (dark grey); Nic. //
C: Arsenopyrite (orange brown, pleochroitic), pyrite (dark) and pyrrhotite (grey to bluish anisotropy),
carbonates (brilliant internal reflections); Nic. +
D: “Sand-glass” twinning of arsenopyrite (dark bluish and brownish grey anisotropy), small pyrite
crystals (isotropic), quartz (white to multicolour internal reflections); Nic. +
E: Arsenopyrite twin (blue and brown anisotropy), pyrrhotite (greenish grey anisotropy), sphalerite
(isotropic, brown internal reflections); Nic. +

Diagnostic Properties of Ore Minerals under Microscope :- Arsenic

2012-09-10T18:49:00.004-07:00

Chemical Configuration: As
Crystal System: Trigonal
Color: Gray, slight brownish
Geologic Environment: hydrothermal veins

Reflectance [%]: 46.95 - 52.76
Anisotropy: distinct, yellowish brown light gray to yellowish gray
Pleochroism :Very Weak

Descriptions

A: Native arsenic (cream, distinctive cleavage); Nic. //
B: Anhedral arsenic (light grey), antimony (white lower part), dyscrasite (cream tint), crust of safflorite
(darker grey than arsenic) covered by pyrargyrite (blue grey); Nic. //
C: Arsenic (brown grey), antimony (grey), dyscrasite (lighter brownish grey), safflorite (blue to
brown to dark anisotropy), pyrargyrite (small red internal reflections); Nic. +
D: Radial arsenic (grey with brownish tint) in matrix of antimony (slightly lighter grey);Nic. //
E: Euhedral native arsenic (cream) overgrown by xanthoconite (bluish grey); Nic. //

Diagnostic Properties of Ore Minerals under Microscope :- Antimony (Stibium)

2012-09-10T18:39:00.001-07:00

Chemical Configuration: Sb
Crystal System: Trigonal
Color: white
Geologic Environment: hydrothermal veins

Reflectance [%]: 68.82 - 70.71
Anisotropy: distinct
Pleochroism :Very Weak

Descriptions
A: Botryoidal antimony (medium grey) with interstitial arsenic patches (slightly darker grey in
lower section); Nic. //
B: Anhedral antimony (white, scratched) below safflorite crust (light grey); Nic. //
C: Antimony (grey) below safflorite crust (blue to brown to grey anisotropy); Nic. +

Diagnostic Properties of Ore Minerals under Microscope :- Alabandite (Manganblende, Blumbachite)

2012-09-09T20:02:00.000-07:00

Chemical Configuration: MnS
Crystal System: Cubic
Color: Gray, Slightly Lighter With Sphalerite
Geologic Environment: epithermal sulfide veins

Internal Reflections: bright green, brown (oxidation)
Reflectance [%]: 21.91
Anisotropy: isotropic

Descriptions

A: Anhedral alabandite (medium grey) replaced by pyrolusite (cream); Nic.//
B: Euhedral alabandite in matrix lamellae of larger alabandite crystals (light grey); Nic. //
C: Alabandite (crystal and lamellae; green internal reflections); Nic. +
D: Alabandite (crystal and lamellae; green internal reflections; core mixture brighter green); Nic. +
E: Oriented exsolution of pyrrhotite (cream tint) in alabandite (medium grey), some pyrite
(white); Nic. //

Occurs as euhedral crystals and as anhedral aggregates; resembles sphalerite. Occurs with Pyrite chelcopyrite pyrrhotite pyrolusite and mangnese carbonates.

Diagnostic Properties of Ore Minerals under Microscope :- Argentite (Argyrite, Silver Glance)

2012-09-09T09:32:00.000-07:00

Argentite (Argyrite, Silver Glance)

Color: gray with a greenish tint
Bireflectance/Peochroism- Very Weak

Geologic Environment: low temperature hydrothermal veins
Reflection Colour:dark grey
Reflectance [%]:[28]
Anisotropy:isotropic, but occasionally slightly bluish grey to dark brown

A: Reaction rim of argentite (greenish grey) between galena (light grey) and native silver (white)
B: Subhedral argentite (medium grey, strongly scratched) next to stephanite (slightly brighter grey,
few scratches)
C: Argentite (twinned, bluish grey to dark brown anisotropy), stephanite (here dark)

Bivalvia Presentation

2012-07-15T18:35:00.000-07:00

NATIONAL MINERAL POLICY, 2008 (For non - fuel and non - coal minerals) Conclusions.

2012-07-15T00:14:00.000-07:00

11. CONCLUSIONS
Mineral wealth, though finite and non-renewable in the long term, is a major resource for
development. The need for a well planned programme of survey and exploration, management
of resources which have already been discovered and those which are in the process of
discovery and their optimal, economical and timely use are matters of national importance.The success of the second national mineral policy will depend largely on a national consensus
to fulfil its underlying principles and objectives.
……

NATIONAL MINERAL POLICY, 2008 (For non - fuel and non - coal minerals) 3

2012-07-15T00:13:00.000-07:00

7. STRATEGY OF MINERAL DEVELOPMENT
7.1 General Strategy
The Strategy for development of any mineral should naturally keep in view its ultimate
end uses in terms of demand and supply in the short, medium and long terms. The guiding
principle in the strategy of development of any mineral or mineral deposit at any location
shall ordinarily be the economic cost of recovery i.e extraction cost relative to market price and
will hence be determined by the market. However, a disaggregated approach in respect of each
mineral will be adopted and a mineral specific strategy will be developed. To maximise gains
from the comparative advantage which the country enjoys intra se mineral development will be
prioritised in terms of import substitution, value addition and export, in that order.
7.2. Conservation and Mineral Development
Conservation of minerals shall be construed not in the restrictive sense of abstinence
from consumption or preservation for use in the distant future but as a positive concept
leading to augmentation of reserve base through improvement in mining methods,
beneficiation and utilisation of low grade ore and rejects and recovery of associated
minerals. There shall be an adequate and effective legal and institutional framework mandating
zero-waste mining as the ultimate goal and a commitment to prevent sub-optimal and
unscientific mining. Non-adherence to the Mining Plan based on these parameters will carry
repercussions. Mineral sectoral value addition through latest techniques of beneficiation,
calibration, blending, sizing, concentration, pelletisation, purification and general customisation
of product will be encouraged. This is particularly important in iron ore mining as about 80% of
the iron ore produced in the country is in the form of Fines and to promote such value addition
fiscal and non fiscal incentives will be considered. A thrust will be given to exploitation of mineral resources in which the country is well endowed so that the needs of domestic industry
are fully met keeping in mind both present and future needs, while at the same time exploiting
the external markets for such minerals.
7.3 Scientific Methods of Mining
Mine development and mineral conservation as governed by the rules and regulations will
be on sound scientific basis, with the regulatory agencies, viz. IBM and the State Directorates,
closely interacting with R&D organisation, and scientific and professional bodies to ensure
optimal Mining Plans. Conditions of mining leases regarding size, shape, disposition with
reference to geological boundaries and other mining conditions shall be such as to
favourably predispose the leased areas to systematic and complete extraction of minerals.
The regulatory agencies, namely the Indian Bureau of Mines and the State Directorates will be
suitably strengthened through capacity building measures.
7.4 Mining as an Industry with Linkages
Mining contributes to the generation of wealth and creation of employment independently and
should therefore be treated as an economic activity in its own right and not merely as an ancillary
activity of manufacturing industry. Domestic processing industry receives supplies of mineral
resources produced by the mining industry at market prices prevailing from time to time. In
order to be assured of uninterrupted supply of the mineral raw material from domestic sources
the user industry will be encouraged to develop long-term linkages with the mineral producing
units including equity participation in such mining companies. The mineral processing unit
should not only get an assured supply of the mineral raw material but should also have
close links with the production and marketing agencies of the mineral based end
products. Mining as a backward linkage and Value addition within the same state as a forward
linkage will, therefore, be encouraged.
7.5 Mining Equipment and Machinery
Indigenous industry for manufacture of mining equipment and machinery shall be strengthened.
Induction of foreign technology and participation for this purpose will be encouraged. Use of
equipment and machinery which improve the efficiency, productivity and economics of mining
operations and safety and health of persons working in the mines and surrounding areas shall be
encouraged. Import of such equipment and machinery shall be freely allowed.
7.6. Manpower Development
Existing facilities for basic and specialised training shall be constantly reviewed and
upgraded from time to time to ensure that adequately trained manpower at all levels is
available for the development of mines and minerals.
In order to improve the competitive edge of the national mining industry, emphasis shall be
laid on mechanisation, computerisation and automation of the existing and new mining
units. The man power development programme shall be suitably reoriented for the purpose.
As the mining sector takes off, the country will need more and more mining engineers,
geologists, geo-physicists, geo-chemists and geo-instrumentation specialists. A comprehensive
review of the sector’s man power needs will be undertaken and educational institutions will be
geared to meeting these needs in the medium and long term.
7.7. Infrastructure Development
Mineral deposits generally occur in remote and backward areas with poor infrastructural
facilities which often inhibit their optimum development. A major thrust needs to be
given to development of infrastructural facilities in mineral bearing areas with special emphasis
on Linking Infrastructure. Financial resources available with government will be leveraged to the
maximum extent possible through recourse to user charge based public-private-partnership
arrangements wherever possible by providing an institutional framework. An enabling
environment will be created to motivate large capacity mining companies to undertake
construction of transportation net works (road and rail) on their own.
The contribution of mineral development to regional and more specifically peripheral
development, commensurate with the huge investment in large mining projects, is substantial. In
so far as public funding of infrastructure is concerned a much greater thrust will be given to
development of health, education, drinking water, road and other related facilities and
infrastructure in mineral bearing areas so that an integrated approach emerges, encompassing
mineral development, regional development and the social and economic well being of the local,
and particularly, tribal population.
7.8 Financial Support for Mining
Mining is an eligible activity for obtaining financial support from financial institutions.
However, at present only those mining projects which have a substantial component of
mining machinery, equipment and buildings are being financed. Steps shall be taken to
facilitate financing of mine development and also of exploration integral to the mining
project. Prospecting being a high risk venture, access to “risk funds” from capital markets and venture
funds will be facilitated. Early stage Exploration and Mining companies will be encouraged and
differential listing requirements through segmented exchanges will be explored. Induction of
foreign technology and foreign participation in exploration and mining for high value and
scarce minerals shall be pursued. Foreign equity investment in joint ventures for exploration
and mining promoted by Indian Companies will be encouraged.
7.9 Small Deposits
Small and isolated deposits of minerals are scattered all over the country. These often lend
themselves to economic exploitation through small scale mining. With modest demand on
capital expenditure and short lead-time, they provide employment opportunities for the local
population. However, due to diseconomies of scale they can also lead to sub-optimal mining and
ecological disturbance. Efforts will be made to promote small scale mining of small deposits
in a scientific and efficient manner while safeguarding vital environmental and ecological
imperatives. Regulation of these conditionalities will be tightened so as to control and prevent
the growth of illegal mining
Where small deposits are not susceptible to viable mining a cluster approach will be adopted by
granting the deposits together as a single lease within a geographically defined boundary. Efforts
would be made to grant such mineral concessions to consortia of small scale miners so that such
clusters of small deposits will enable them to reap the benefits of economies of scale.
In grant of mineral concessions for small deposits in Scheduled Areas, preference shall be given
to Scheduled Tribes singly or as cooperatives.
7.10. Mineral Development & Protection of Environment
Extraction of minerals closely impacts other natural resources like land, water, air and
forest. The areas in which minerals occur often have other resources presenting a choice
of utilisation of the resources. Some such areas are ecologically fragile and some are
biologically rich. It is necessary to take a comprehensive view to facilitate the choice or
order of land use keeping in view the needs of development as well as needs of
protecting the forests, environment and ecology. Both aspects have to be properly
coordinated to facilitate and ensure a sustainable development of mineral resources in
harmony with environment.

Mining activity often leads to environmental problems like land degradation in opencast mining
and land subsidence in underground mining, deforestation, atmospheric pollution, pollution
of rivers and streams, soil erosion due disposal of solid wastes like overburden and so on,
all affecting the ecological balance of the area. Open-cast mining in areas with actual forest
cover leads to deforestation. Prevention and mitigation of adverse environmental
effects due to mining of minerals and repairing and re-vegetation of the affected forest
area and land covered by trees in accordance with the latest internationally acceptable norms and
modern afforestation practices shall form integral part of mine development strategy in every
instance. All mining shall be undertaken within the parameters of a comprehensive Sustainable
Development Framework which will be so devised as to take all these aspects into consideration.
The guiding principle shall be that a miner shall leave the mining area in better ecological shape
than he found it.
Mining operations shall not ordinarily be taken up in identified ecologically fragile and
biologically rich areas. Strip mining in forest areas should be avoided and it should
be permitted only when accompanied with comprehensive time-bound reclamation
programme.
No mining lease would be granted to any party, private or public, without a proper mining
plan including the environmental management plan approved and enforced by statutory
authorities. The environmental management plan should adequately provide for controlling
the environmental damage, restoration of mined areas and for planting of trees according
to the prescribed norms. As far as possible, reclamation and afforestation will proceed
concurrently with mineral extraction.
Efforts would be made to convert old disused mining sites into forests and other appropriate
forms of land use.
7.11 Relief & Rehabilitation of Displaced and Affected Persons
Mining operations often involve acquisition of land held by individuals including those
belonging to the weaker sections. In all such cases a social impact assessment will be undertaken
to ensure that suitable Relief and Rehabilitation packages are evolved. While compensation is
generally paid to the owner for his acquired land, rehabilitation of affected persons in the form of
substitute land, land for housing and jobs is not always adequate. Appropriate compensation will
form an important aspect of the Sustainable Development Framework mentioned in para 2.3 and
7.10 above. In so far as indigenous (tribal) populations are concerned the Framework shall
incorporate models of stakeholder interest for them in the mining operation, especially in
situations where the weaker sections like the local tribal populations are likely to be
deprived of their means of livelihood as a result of the mining intervention.

In areas in which minerals occur and which are inhabited by tribal communities and weaker
sections it is imperative to recognize resettlement and rehabilitation issues as intrinsic to the
development process of the affected zone. Thus all measures proposed to be taken will be
formulated with the active participation of the affected persons, rather than externally imposed.
A careful assessment of the economic, environmental and social impact on the affected persons
will be made. A mechanism will be evolved which would actually improve the living standards
of the affected population and ensure for them a sustainable income above the poverty line. For
this purpose, all the provisions of the National Rehabilitation and Resettlement Policy or any
revised Policy or Statute that may come into operation, will be followed.
7.12 Mine Closures
Once the process of economical extraction of a mine is complete there is need for
scientific mine closure which will not only restore ecology and regenerate bio mass but also take
into account the socio-economic aspects of such closure. Where mining activities have been
spread over a few decades, mining communities get established and closure of the mine
means not only loss of jobs but also disruption of community life. Whenever mine
closure becomes necessary, it should be orderly and systematic and so planned as to
help the workers and the dependent community rehabilitate themselves without undue
hardship.
7.13. Mine Safety
Mining operations are hazardous in nature. Accidents happen and often result in the loss of
life or limb of persons engaged in it. Efforts must be directed towards the development
and adoption of mining methods which would increase the safety of workers and reduce
the accidents. Towards this end, participation and cooperation of mine workers shall be
secured. Steps will also be taken to minimise the adverse impact of mining on the
health of workers and the surrounding population.
8. FOREIGN TRADE
Minerals continue to be an important source of foreign exchange earnings. The policy of export
shall keep in view the dynamics of mineral inventories as well as the short, medium and long
term needs of the country. Efforts shall be made to export minerals in value added form
as far as possible. The indigenous mineral industry shall be attuned to the
international economic situation in order to derive maximum advantage from foreign trade
by carefully anticipating technology and demand changes in the international market
for minerals.

The import of mineral based material shall be coordinated as far as possible with the
indigenous development of mineral based industries. Areas of cooperation with
countries with complementary resource base shall be developed for mutual advantage.
The approach shall be to make available mineral based materials to domestic users at
reasonable prices as determined by market forces.
A long term export policy would provide stability and prove to be an incentive for investing in
large scale commercial mining activity. To develop mining as a modern stand alone industry
substantial investment is required. Assurances on export of minerals will be a key factor for
investment decisions particularly on FDI in the sector. The Export Policy should be based on a
clear long term strategy for export of minerals taking these aspects into consideration.
9. FISCAL ASPECTS
It will be the endeavour of government, within the context of the budget, to design fiscal
measures conducive to the promotion of mineral exploration and development including
beneficiation and other forms of product refinement. In the context of the changing mineral
scenario and the economies of mineral development and products, both at the national and
international level fiscal changes will be examined from time to time consistent with the general
tax structure and through the normal budgetary process. Mineral prices should reflect their value
and the royalty structures will be designed to ensure that the producer earns and the consumer
pays the true value of the minerals produced and consumed. The fiscal dispensation will
generally aim to ensure that adequate compensation is forthcoming to the state in return for the
concessions it grants.
10. RESEARCH AND DEVELOPMENT
10.1. General Approach
Research and development in the mineral sector has to cover the entire gamut of activities
from geological survey, exploration, mining, beneficiation, concentration of minerals to
development of materials. Efforts will be directed towards the development of new
technologies for conversion of existing mineral resources into viable economic resources.
Appropriate technologies shall be developed to enable indigenous industries to utilise
the mineral resources with which the country is abundantly endowed and as substitutes
for minerals whose reserves are poor. R&D efforts shall be directed to find new and
alternative uses for minerals whose traditional demand is on the wane. Indigenous technology
has to be upgraded through research and appropriate absorption and adoption of
technological innovations abroad. Research and development efforts shall be made to
improve efficiency in process, operations and also the recovery of by-products and reduction in specification and consumption norms. Efforts will also be directed to evolve
low capital and energy saving processing systems.
10.2. Research in Mining Methods
Mining methods determine the safety, economy, speed and the percentage of extraction of the
ore reserves from a mine. Research and development thrust shall be directed specially in the
areas of rock mechanics, ground control, mine design engineering, equipment deployment
and maintenance, energy conservation, environmental protection, safety of operations and
human engineering.
10.3 Mineral Processing and Beneficiation
Attention will be given to beneficiation and agglomeration techniques to bring lower grades and
finer size material into use. Research organisations, including the National Mineral
Processing Laboratories of the Indian Bureau of Mines will be strengthened for
development of processes for beneficiation and mineral and elemental analysis of ores
and ore dressing products. There shall be cooperation between and coordination among all
organisations in public and private sector engaged in this task. Research and development shall
be oriented to ensure maximum economic recovery of the associated minerals and
valuable metals.
10.4 Development Of Automated Equipment
To meet the objective of safety and economic production attention will be given to the
development of robotics, automated equipment and system for mining, especially for deep
mining and transportation to surface.
10.5. Deep Sea Mining
India is a pioneer investor and has been allocated a mine site of 150,000 square kilometres in
Indian Ocean for exclusive survey and exploration. Deep ocean resources represent an
exceptionally large and potentially important mineral resource. Integrated systems for
exploration, exploitation, mining and processing of these resources shall be expedited
with the development/acquisition of necessary technologies. Appropriate mechanism
for coordinating the survey and exploration of Deep Sea Bed Area will be established by
the Ministry of Earth Sciences.

10.6 Production Of Materials Of High Purity
Research will be directed towards raw materials required for production of materials of
high purity for use in advanced technology applications such as semi-conductors,
photo-voltaic, lasers, special sensors, high temperature new ceramics, hard and high
temperature materials, superconductors, insulators, very thin films, glasses and liquid
crystals and metal and mineral fibres.
10.7. Coordination Of Research Organisations
Research and development activities in the mineral sector are carried out in the national
laboratories, educational institutions and R&D units of public and private sector
enterprises. Pooling of resources and expertise available in the various R&D
Organisations is imperative to meet the challenges and to fulfil the tasks ahead in the
mineral sector. Linkages and interaction between the various institutions engaged in
R&D in the mineral sector shall be strengthened to derive the maximum benefit.
Interchange of scientists between institutions shall be encouraged to accelerate the pace of
interaction. It shall also be ensured that the research findings are made available to users
expeditiously. There shall be cooperation between and coordination among all organisations in
the public and private sectors engaged in this task.
Mining methods determine the safety, economy, speed and the percentage of extraction of the
ore reserves from a mine. Research and development thrust needs to be directed in areas of such
as rock mechanics, ground control, mine design engineering, equipment deployment and
maintenance, energy conservation, environmental protection, safety of operations and human
engineering. This has to be done in a holistic way so that inter-linkages are established to the
advantage of each segment. To this end the diverse research, development and training initiatives
within the public domain shall be reorganised into a single and cohesive R & D and Training
institution of excellence to be known as the National Institute of Mineral Development.
Organizations such as the National Mineral Processing Laboratories of the Indian Bureau of
Mines, the National Institute of Rock mechanics, the Jawaharlal National Institute of Aluminium
Research and Development, the R & D initiatives of the Geological Survey of India will be
joined to provide a collective thrust.

NATIONAL MINERAL POLICY, 2008 (For non - fuel and non - coal minerals) 2

2012-07-15T00:09:00.002-07:00

3. REGULATION OF MINERALS
3.1. Management of mineral resources is the responsibility of both the Central Government
and the State Governments in terms of Entry 54 of the Union List (List I) and Entry 23
of the State List (List II) of the Seventh Schedule of the Constitution of India. The
Mines and Minerals ( Development and Regulation) Act, 1957 (MMDR Act), lays down the
legal frame-work for the regulation of mines and development of all minerals other than
petroleum and natural gas. The Central Government has framed the Mineral Concession
Rules, 1960 (MCR) for regulating grant of reconnaissance permits (RP), prospecting licences
(PL) and mining leases (ML) in respect of all minerals other than atomic minerals and
minor minerals. The State Governments have framed the rules in regard to minor minerals.
The Central Government have also framed the Mineral Conservation and Development
Rules, 1988 (MCDR), for conservation and systematic development of minerals. These
are applicable to all minerals except coal, atomic minerals and minor minerals
3.2. The Central Government in consultation with State Governments shall formulate the
legal measures necessary for giving effect to the new National Mineral Policy, 2008, to
ensure basic uniformity in mineral administration across the country and to ensure
that the development of mineral resources keeps pace, and is in consonance with the national policy goals. The MMDR Act, the MCR and the MCDR will be amended in line with
the policy. The regulation of mines and development of mineral resources in
accordance with the national goals and priorities as spelt out in the policy and the legal
framework shall be the responsibility of both the Central and the State Governments.
3.3 In order to make the regulatory environment conducive to private investment the
procedures for grant of mineral concessions of all types, such as Reconnaissance Permits,
Prospecting Licenses and Mining Leases, shall be transparent and seamless and security of
tenure shall be guaranteed to the concessionaries. The first-in-time principle in the case of sole
applicants and the selection criteria in the case of multiple applicants will be appropriately
elaborated. Prospecting and mining shall be recognized as independent activities with
transferability of concessions playing a key role in mineral sector development.
4. ROLE OF THE STATE IN MINERAL DEVELOPMENT
The role to be played by the Central and State Governments in regard to mineral development
has been extensively dealt in the Mines and Minerals (Development and Regulation) Act,
1957 and Rules made under the Act by the Central Government and the State Governments
in their respective domains. The provisions of the Act and the Rules will be reviewed and
harmonised with the basic features of the new National Mineral Policy. In future the core
functions of the State in mining will be facilitation and regulation of exploration and mining
activities of investors and entrepreneurs, provision of infrastructure and tax collection. In mining
activities, there shall be arms length distance between State agencies (Public Sector
Undertakings) that mine and those that regulate. There shall be transparency and fair play in the
reservation of ore bodies to State agencies on such areas where private players are not holding or
have not applied for exploration or mining, unless security considerations or specific public
interests are involved.
5. SURVEY AND EXPLORATION
5.1. The Geological Survey of India is the principal agency for geological mapping and
regional mineral resources assessment of the country. It shall be responsible for drawing
up action oriented plans towards these ends in close cooperation with all other agencies
engaged in this task. Detailed exploration on land is done by the Mineral Exploration
Corporation, Directorates of Mining and Geology of the State Governments and various Central
and State Public Sector Organisations. In conducting exploration for minerals special attention
will be given by these government agencies to the development of strategic minerals through
systematic investigation of potential sources which are difficult to otherwise access. 5.2 While these Government agencies will continue to perform the tasks assigned to them for
exploration and survey, the private sector would in future be the main source of investment in
reconnaissance and exploration and government agencies will expend public funds primarily in
areas where private sector investments are not forthcoming despite the desirability of
programmes due to reasons such as high uncertainties. To expedite completion of reconnaissance
work for the entire country as early as possible an open sky policy of non-exclusivity for
reconnaissance work will be adopted. At the same time to attract large investments and high
technology a new instrument to be known as Large Area Prospecting License will be introduced.
However such bulk minerals which do not need risk investment and high technology will not be
eligible for Large Area Prospecting License. The durations of all concessions will be rationalised
and areas of operations enlarged suitably within each state.
5.3 It is necessary to ensure that India’s exclusive economic zone is explored and exploited to
the maximum possible extent. The Ministry of Earth Sciences (MoES) and its agencies are
entrusted with the task of sea-bed exploration and mining. Cooperation between MoES and GSI
will be institutionalised so as to achieve this objective within a time bound framework. The task
of mapping out the extended economic zone will be expedited and completed within the time
prescribed by the International Sea Convention so that no area of sea bed mining is lost to the
country.
5.4 Particular attention will be given to the survey and exploration of minerals in which
the country has a poor resource-cum-reserve base despite having the geological potential for
large resources. Minerals for which there is demand within the country either for use or for
export after processing will be prioritised. Exploration for lower grade hematite, magnetite, base
metals, noble metals, diamonds and high grade Ilmenite will be put on the fast track.
5.5 Coordination of the regional exploration work by government agencies is at present
being done by the Central Programming Board of the Geological Survey of India. The
disaggregated projects are generally discussed in the State Level Committees and other technical
forums before being incorporated into the annual programme. The existing arrangement shall be
revamped to ensure that projects and programmes are prioritised in line with the national policy
goals and are chalked out after taking into account the exploration work undertaken by the
private sector.

6. DATA BASE OF MINERAL RESOURCES AND TENEMENTS
6.1. The national inventory of mineral resources will be based on a comprehensive and up to
date review of exploration data. In coordination with Geological Survey of India, the Indian
Bureau of Mines will maintain a database in digitised form comprising both a Resource
Inventory and a Tenement Registry. The resource inventory will be in accordance with the latest version of the UNFC system showing reserves and remaining resources as well in the traditional
IBM form of resources and probable and proven reserves. The Tenement Registry will give
information of both Leasehold Areas as well as Freehold Areas in terms of green field, brown
field and relinquished areas including areas given up by the GSI and other RP/PL holders as not
pursued. The data would be maintained online giving instant information to prospective investors
on what is available for reconnaissance, prospecting and mining. Summaries of work done by
public agencies will be kept in the form of meta-data in the public domain and detailed reports
will be made available to interested investors on cost recovery basis.
6.2 Data filing requirements will be rigorously applied and all concession holders will be
subjected to detailed monitoring in this regard. The lock-in arrangements will be assured and
released data will be integrated with the data generated by the state agencies and made available
to other prospectors.

NATIONAL MINERAL POLICY, 2008 (For non - fuel and non - coal minerals)

2012-07-15T00:07:00.002-07:00

1. PREAMBLE
Minerals are a valuable natural resource being the vital raw material for infrastructure,
capital goods and basic industries. As a major resource for development the extraction and
management of minerals has to be integrated into the overall strategy of the country’s
economic development. The exploitation of minerals has to be guided by long-term
national goals and perspectives. Just as these goals and perspectives are dynamic and
responsive to the changing global economic scenario so also the national mineral policy has
to be dynamic taking into consideration the changing needs of industry in the context of the
domestic and global economic environment. It is, therefore, necessary to revisit the National
Mineral Policy, 1993, as provided in para 4 of the same, and to spell out in a revised
statement the different elements of policy, including elements newly evolved, for the
development of the mineral resources of the country.
2. BASIC FEATURES
2.1 The country is blessed with ample resources of a number of minerals and has the
geological environment for many others. To exploit the country’s geological potential it is
important that scientific and detailed prospecting is carried out in search of its mineral resources.
It will be ensured that regional and detailed exploration is carried out systematically in the
entire geologically conducive mineral bearing area of the country using state-of-the-art
techniques in a time bound manner. Minerals being a valuable resource the extraction of mineral
resources located through exploration and prospecting has to be maximised through scientific
methods of mining, beneficiation and economic utilisation. Zero waste mining will be the
national goal and mining technology will be upgraded to ensure extraction and utilisation of the
entire run-of-mines.
2.2 To achieve both these goals of large scale prospecting and optimal mining large
investments will be required together with the latest technologies in prospecting and mining.
The regulatory environment will be improved to make it more conducive to investment and
technology flows. Capital market structures will be developed to attract risk investment into
survey and prospecting. Transparency in allocation of concessions will be assured. Preference
may be given to a value addition industry in grant of mineral concession. However, this will not in any way undermine the security of tenure to a holder of a concessionaire. The
development of a proper inventory of resources and reserves, a mining tenement registry and a
mineral atlas will be given priority. Enforcement of mining plans for adoption of proper
mining methods and optimum utilisation of minerals will be ensured. For these purposes the
Geological Survey of India (GSI), the Indian Bureau of Mines (IBM) and the State Directorates
of Mining & Geology will be strengthened with man power, equipment and skill sets upgraded
to the level of state of the art.
2.3. Mining is closely linked with forestry and environment issues. A significant part of the
nation’s known reserves of some important minerals are in areas which are under forest cover.
Further, mining activity is an intervention in the environment and has the potential to disturb
the ecological balance of an area. However, the needs of economic development make the
extraction of the nation’s mineral resources an important priority. A framework of sustainable
development will be designed which takes care of bio diversity issues and to ensure that
mining activity takes place along with suitable measures for restoration of the ecological
balance. Special care will be taken to protect the interest of host and indigenous (tribal)
populations through developing models of stakeholder interest based on international best
practice. Project affected persons will be protected through comprehensive relief and
rehabilitation packages in line with the National Rehabilitation and Resettlement Policy.
2.4 As the country develops and industry grows assured availability and proximity of
mineral resources will play an important role in giving a competitive edge to Indian industry.
The multiplier effect of minerals processed into metals on downstream industrialisation cannot
be over emphasised. Value addition will, therefore, be actively encouraged. However, such
value addition will go hand in hand with the growth of the mineral sector as a stand alone
industrial activity. While, appropriate linkages between exploitation of minerals and their
end use including the development of industry based on the minerals will be established
wherever feasible, a downward curve in an industrial sector using a particular mineral within
the country need not be allowed to effect the growth of mining activity for that mineral. Hence
employment and tertiary sector spin offs from both value addition as well as from mining will
be encouraged so as to maximise the contribution of the mineral sector to the country’s gross
domestic product.
2.5 Mining infrastructure requires a special thrust as the economic efficiency of evacuation of
minerals from pit mouth to user point or port or rail head is closely linked to the end use value
of the mineral and of the viability of the industry using the mineral. Innovative structures will
be devised for developing and financing the infrastructure needs of the mining sector. While
assistance through viability gap funding will be extended where required the principle of user
charges and Private Public Participation will be the basis on which mining infrastructure will be
built. 2.6 India is a federal structure with a single economic space. Nevertheless, the legitimate fiscal
interests of States which are mineral rich need to be protected. The revenues from minerals will
be rationalised to ensure that the mineral bearing States get a fair share of the value of the
minerals extracted from their grounds. New sources of revenue will be developed for the States
and State agencies involved in mineral sector development and regulation will be encouraged to
modernise in the areas of prospecting as well as regulation. The States will be assisted to
overcome the problem of illegal mining through operational and financial linkages with the
Indian Bureau of Mines.
2.7 To enable the use of state of the art exploration techniques, scientific mining and optimal
use of minerals through ore dressing and beneficiation technologies it is necessary not only to
promote research and development in minerals but to simultaneously establish appropriate
educational and training facilities for human resources development to meet the manpower
requirements of the mineral industry. These matters will receive prime importance and a
comprehensive institutional framework for Research & Development, and Training will be
developed.
2.8 These aspects constitute the essentials of the new National Mineral Policy, 2008. A more
detailed approach towards putting these essentials into practice and details of other associated
features of the Policy are spelt out in the following paragraphs.

Forensic Geology: Earthly Remains - Rachit Parihar

2012-07-14T23:31:00.000-07:00

Department of Geology, M.L. Sukhadia University, Udaipur

Email: rachit.parihar@gmail.com

Abstract: Geology has always supported mankind in all sorts of ways for its survival as well as prosperity. Now in modern times where sometimes humanity is threatened by itself, legal limits are crossed and forensic science is in need of support, merciful mother earth provides us with another powerful tool to support evidences, convict criminals and bring justice to those who are harmed. Forensic Geology relates the disciplines of earth science to the field of criminology.

Keywords: Forensics; Geology; Crime; Evidence; Law; Criminal Investigation.

Since time immemorial it has been proved over and over again that new disciplines and sciences are praised and rediscovered by people who possess God gift of thinking and intelligence.

All sub-disciplines of the geosciences have potential forensic applications, but sedimentology, mineralogy, petrology, geochemistry, palaeontology and geophysics have so far made the greatest contributions. Shallow geophysical prospecting methods have been widely used by forensic geologists and others to locate and characterize clandestine graves and buried objects such as drugs and weapons. However, probably the most widely recognized application of forensic geology is the use of geological materials as trace evidence which can be of value in linking a suspect to a crime scene. In the wider forensic and legal literature, sediment, soil, dust and rock fragments have often been grouped together under the loose term ‘soil’ evidence.

Types of information provided by geological and soil evidence include:

- was an individual, motor vehicle or other specified item present at a particular location e.g. crime scene

- what was the sequence, and possible timing, of a visit to that location and possibly others

- the location of buried objects e.g. bodies, arms caches, drugs

- the source of imported / smuggled items

- the cause of death (especially possible drowning and suffocation)

- the geographical origin of unidentified human remains

- the length of time a body has been present at a location, and length of post-mortem interval

The application of Geology in investigation, began with the writings of Sir Arthur Conan Doyle through his character Sherlock Holmes between 1887 and 1893. Starting with that various scientists and investigators worked with forensics and geology together there by giving rise to a new science Forensic Geology.

The work of these men had an important influence on Edmund Locard, initially a student of forensic medicine, who later went on to be Director of the Technical Police Laboratory in Lyons, France. Locard developed the first detailed scientific procedures for the analysis of dust traces, and established the famous Locard exchange principle:

Whenever two objects come into contact, there is always a transfer of material. The methods of detection may not be sensitive enough to demonstrate this, or the decay rate may be so rapid that all evidence of transfer has vanished after a given time. Nonetheless, the transfer has taken place.

Most of above details and information clearly states that all evidences have equal status as and when required of the hand of the law and to differentiate one person from guilty to innocent. But unfortunately this importance is not applied and is often unacceptable in the Indian Justice System and IPC there is need to create awareness so that these tools be identified by the court and used by legal hand so that this science also be much appreciated and researched on in India.

The topic in hand is very juvenile and very often neglected in Indian scenario to be concluded with any summaries or conclusions but it must be worked on by us so that we can contribute in our nation's progress.

Case Histories in the given Field: As told beforehand this topic does not have much work done on in India so all cases presented are foreign:

First criminal case using earthen materials as evidence:

In October, 1904, a seamstress had been strangled in a bean field with her own scarf. A handkerchief had been left at the scene and the nasal mucus on the handkerchief contained bits of coal and, most interesting, grains of minerals, particularly the mineral horneblende. A forensic geologist found coal and mineral grains, particularly the mineral horneblende, under the suspect’s fingernails. Examination of soil removed from suspects’s trousers revealed a lower layer in contact with the cloth whose minerals compared with those found in a sample collected from the place where the body had been found! Encrusted on top of this lower layer a second soil type was found. Examination of the minerals in the upper layer revealed a mineralogy and size of particle, particularly a crushed mica grain, comparable with soil samples collected from the path that led from the murder scene to the suspects home.

Beach sand and murder :

In the United States, Colma, California, on the night of August 2, 1921, the parish priest, Father Patrick Heslin, was kidnapped. A ransom note was received, but no further contact was made and the priest was assumed to have been murdered.

Investigators examined the place on the California beach where a suspect indicated the body of Father Heslin would be found. The body was found and the investigation also produced a number of objects of physical evidence, such as boards from a tent floor. Investigators studied grains of sand recovered from suspect’s knife and pronounced them similar to the sand on the beach where the body was found. In suspect’s room a tent was found, and the tent contained an abundance of sand, which, when studied, confirmed the results from the knife. It appeared that the suspect had kidnapped and murdered Father Heslin and kept his body in the tent on the beach for several days before burying it in the sand.

Commercial sand from a construction site:

In another example, a man was arrested and charged with the beating and death of the young girl. The scene of the crime was a construction site adjacent to a newly poured concrete wall. The soil was sand that had been transported to the scene for construction purposes. As such, the sand had received additional mixing during the moving and construction process and was quite distinctive. The glove of the suspect contained sand that was similar to that found at the scene and significantly different in composition and particle size from the area of the suspect’s home. This was important because the suspect claimed the soil on the gloves came from his garden.

Hit-and-Run auto from the Missouri lead-zinc mining belt

In another case, the soil dislodged from the fender or frame of an automobile during a hit-and-run accident provided a clue to the area where the car had been driven and thus the possible home or past driving area of the person responsible. In the case of a fatal hit-and-run accident in the upper Midwest, clumps of soil dislodged from the fender of the car as it struck the victim and sped away were shown to contain the characteristic minerals of the Missouri lead-zinc mining district hundreds of miles to the south. This knowledge contributed to the successful search for a suspect. When the suspect was apprehended and soil from under the fenders of his car was studied, it was found to compare with the material collected from the highway at the scene of the crime. Furthermore, it was subsequently shown that he had previously driven though mining areas of Missouri where rocks from the mines were used as road bed material.

Acknowledgements: I remain fully responsible for any errors and omissions present in this paper. I greatly appreciate the support of my family, friends, and my teachers Dr. P.C. Avadich, Dr. P Kataria, Dr. N. K. Chauhan, Dr. Harsh Bhu, Dr. S.R. Jakhar , and last certainly never the least Dr. Vinod Agarawal (H.O.D.) for their valuable support and guidance.

References:

Murray R.C. : Evidence from the earth.

Ruffell A, McKinley J : Geoforensics.

Pye K. : Forensic Geology.

Murray R.C. ,Tedrow John C.F.: Forensic Geology

Garnet family

2011-11-12T08:50:00.000-08:00

Garnet Family.

GARNETS

This is a group of six minerals which are isomorphous in nature, and never occur pure as represented by their chemical composition.

1. Atomic structure. These are neo-silicates, formed of independent Si0₄ tetrahedra.

2. Chemical composition. The general formula for the garnets isR₃^111,R2¹¹¹Si₃O₁₈, where R¹¹ can be Fe¹¹, Mg, Mn¹¹ or Ca, and R¹¹¹can be Fe^m, A1 or Cr.

3. Classification. Mainly there are two groups as :

(i) Pyralspite. Containing three members like :

(a) Pyrope. Mg3Al₂(Si0₄)₈.

(b) Almandite. Fe^Al^O*),.

(ii) Ugrandite. It consisting of three members like:

(a) Uvarovite. Ca₃Cr₂(Si04)₃.

(b) Grossularite. Ca₃Al₂(SiO_J)₃.

4. Physical properties:

(i) Garnets are externally cubic in form (Rhombododeca- hedron).

(ii) Any colour except blue ; grossularite, uvarovite green* pyrope, almandite, and spessartite are deep red to black in colour, while andradite is black in colour.

(iii) Lusture. Vitreous to sub-vitreous.

(iv) Cleavage. None.

(v) Hardness. 7.

Sp.gravityHigh

Garnets

5. Optical properties:

(i) Non-pleochroic colourless, sometimes pale pink in colour. Uvarovite is green in colour.

(ii) Ref. index. Very high,

(iii) Under crossed nicol. Dark, i.e. isotropic.

6. Varieties:

(i) Melanite. Black andradite.

(ii) Schorlomite. Titaniferous andradite.

(iii) Demontoid. Clear-green andradite.

(iv) Hessoniie. Also known as cinnamon stone is a yellow- brownish variety of grossularite.

(v) Tbpozolite. Yellow-andradite.

Occurrence. Garnets are usually metamorphic minerals, but some also occur in igneous and sedimentary rocks. But everywhere they are characterised by their typical rhombododecahedron and trapezohcdron forms.

Textures of Ore Deposits and associated features

2011-11-12T08:46:00.001-08:00

Importance of studying textures

Textural identification and interpretation for ore deposits and associated gangue minerals are tools necessary for understanding the processes involved in the genesis of these deposits, which in turn is very important for prospecting for other similar economic bodies. Specifically, textural studies are useful for:

1- Understanding the timing of formation of the ore minerals relative to the host rocks and their structures

2- Determining the sequence of events or depositional history within an ore body

3- Determining the rates of cooling or of ore mineral accumulation (in some cases).

4- Identifying the equilibrium mineral assemblages, which in turn are necessary for understanding phase relations and the correct interpretation of geothermometric results.

Textures of economic ore deposits

I- Magmatic ores:

1- Cumulus textures: result from the settling of an ore deposit from a crystallizing magma. The most common example is chromite which occurs as a cumulus phase relative to pyroxenes.

2- Intergranular or intercumulus textures: where the ore mineral occurs as an intergranular anhedral phase relative to the other gangue minerals. In such cases, this ore mineral crystallizes late in the magmatic sequence (relative to the other gangue minerals) so takes up the shape of the intergranular spaces left behind. Examples include numerous sulfides, in many cases crystallizing from liquids immiscible with, and of lower melting point than the silicate magma.

3- Exsolution textures: Where one phase separates from another as a result of incomplete miscibility during cooling, and has a tendency to concentrate along certain crystallographic directions (e.g. cleavage planes). Examples include the occurrence of ferrian ilmenite in titanohematite or ilmenite in ulvospinel. Exsolution textures usually indicate a slow or intermediate cooling rate. In some cases, exsolution textures are difficult to tell apart from some textures that form by replacement.

II- Textures of hydrothermal ore deposits and skarns:

A- Replacement textures:

Replacement is the process of almost simultaneous solution and deposition by which a new mineral of partly or totally different chemical composition may grow in the body of an old mineral or mineral aggregate. According to this definition, replacement is accompanied by very little or no change in the volume of the rock. However, in practice, this process is accompanied by expansion or contraction (and it has proven quite challenging to write balanced chemical reactions representing replacement textures in which the volume of the products and reactants is the same!). Replacement is more common at high T and P where open spaces are very limited or unavailable, and fluid flow is rather difficult. It also depends largely on the chemical composition and reactivity of both the host rock and the hydrothermal solution.

In general, it has been observed that certain minerals replace others preferentially. Accordingly, a set of "rules" has been proposed:

a) Sulfides replace gangue or ore minerals

b) Gangue minerals replace host rock, but not the ore minerals

c) Oxides replace host rock and gangue, but rarely replace sulfides.

Criteria for identifying replacement textures:

1) Pseudomorphs.

2) Widening of fractures

3) Vermicular unoriented intergrowths

4) Islands (of the host or replaced mineral) having the same optical orientation and surrounded by the new mineral

5) Relicts

6) Cusp and caries texture: (host or replaced mineral). Cusps are relict protuberances of the replaced mineral or host rock between “caries”. The caries are embayed surfaces concave towards the replacing mineral into the replaced one

7) Non-matching walls of a fracture. This is a feature common when replacement works outward from a central fissure (compare with open space filling textures)

8) The occurrence of one mineral crosscutting older structures.

9) Topotactic and epitactic replacement: Topotaxy is a process where the replacing mineral overgrows the replaced one along certain crystallographic directions controlled by the structure of the replaced mineral. Epitaxy is the same process except that the structure of the replacing (new) mineral is not controlled by the replaced mineral, but instead by other "matrix" minerals.

10) Selective association: Since replacement is a chemical process, specific selective associations of pairs or combinations of minerals can be expected. For example, chalcopyrite is more likely to replace bornite by a change in the Cu/Fe ratio or in fS2 than it is to replace quartz. Therefore, the occurrence of minerals with some chemical similarity in some textural relationship is often a good indication of replacement

11) The presence of a depositional or paragenetic sequence in which minerals become progressively richer in one or more elements

12) Gradational boundaries: In contrast to open space deposition which produces abrupt textures and structures between the hydrothermally deposited minerals and their host rocks, replacement is often accompanied by gradational boundaries between both minerals. Accordingly, gradational boundaries are a good indication of replacement.

13) Deposition of one or more hydrothermal minerals along a clear alteration front.

14) Doubly terminating crystals: If a crystal grows within an open cavity, it is normally attached to one of the walls of the fracture, and can develop crystal faces only on the other end (i.e. the one away from this wall). In contrast, the process of replacement may result in the growth of euhedral crystals with well developed faces on more than one end.

15) The lack of offset on a fracture intersected by the replacing mineral: In contrast to open space filling which may be associated with displacement of a preexisting structure by the fracture being filled by hydrothermal fluids, replacement across a preexisting structure will not be accompanied by such offset. The same holds true for two intersecting fractures

B- Open space filling textures

Open space filling is common at shallow depths where brittle rocks deform by fracturing rather than by plastic flow. At these shallow depths, ore bearing fluids may circulate freely within fractures, depositing ore and gangue minerals when sudden or abrupt changes in P and/or T take place. As such, open space filling textures will be different from those resulting from replacement, and a set of criteria may be used to identify this process. Nevertheless, many hydrothermal ore deposits form by the combined effects of replacement and open space filling, which requires a lot of caution in textural interpretation.

Criteria for identifying open space filling processes:

1- Many vugs and cavities

2- Coarsening of minerals from the walls of a vein to its centre

3- Comb structure: Euhedral prismatic crystals growing from opposite sides of a fissure symmetrically towards its centre develop an interdigitated vuggy zone similar in appearance to that of the teeth of a comb

4- Crustification: Crustification results from a change in composition and/or physicochemical conditions of the hydrothermal solution, and is represented by layers of different mineralogies one on top of the other.

5- Symmetrical banding

6- Matching walls: If an open fissure has been filled without replacement, the outlines of opposite walls should match

7- Cockade structure: Mineralization within the open spaces of a breccia or any other fragmental rock will commonly produce a special pattern of symmetrical banding and crustification where each opening acts as a centre for sequential deposition

8- Offset oblique structures

In addition to replacement and open space filing textures, very low temperature hydrothermal deposits (epithermal and telethermal deposits) are often characterized by colloform habits and banding described in the following section.

III- Textures characteristic of surfacial or near surface environments and processes:

Under surfacial conditions, ore minerals may be deposited from colloidal solutions. A colloid is defined as a system consisting of two phases; one diffused in the other. Colloidal particles range in size between ions in a true solution and particles that are < 10^-3 cm in a coarse suspension. The colloidal material may be solid, liquid or gas dispersed in another solid, liquid or gas.

Colloidal solutions believed to be responsible for the formation of ore deposits usually consist of solids dispersed in liquids and are called "sols". In such sols, colloidal particles commonly adsorb either cations or anions, and thus acquire similar charges which cause them to repel each other, preventing them from coagulation. If an electrolyte is added to such a sol, the colloidal particles are neutralized and flocculate giving rise to a variety of textures which include:

a) Botryoidal or reniform aggregates

b) Banding or very fine layering

c) Leisegang rings

These textures are broadly lumped as "colloform" textures. Because some colloform textures were observed in some hydrothermal deposits, it was believed that some hydrothermal solutions were colloids. However, fluid inclusion analysis showed that hydrothermal solutions are too saline to have been in the colloidal state, and the term "colloform" should be considered descriptive and non-genetic.

In the surfacial environment, colloidal solutions are common. Criteria used to identify a colloform texture as a product of deposition from a colloidal solution include:

1) Shrinkage cracks: which develop due to dehydration of a gel

2) Liesegang rings: Are coloured bands that form when an electrolyte is allowed to diffuse into a gel. Liesegang rings are common in amorphous, cryptocrystalline and microcrystalline "minerals" or mineraloids as agate and opal.

3) Variable composition of bands and/or deposits: This phenomenon is due to the ability of colloids to adsorb different ions from their surroundings.

4) Non-crystalline structure: The occurrence of amorphous "minerals" or mineraloids (e.g. opal) is an indication of formation from a colloidal solution. However, such mineraloids will tend to crystallize with time.

5) Spheroidal texture: Are rounded objects similar to pisolites, which result from the low surface tension of a colloid.