1Author: Partha Das Sharma (B.Tech – Hons., in Mining Engineering)

Website: http://miningandblasting.wordpress.com/

SUSTAINABLE DEVELOPMENT

Aims at meeting the needs of present generation without adversely affecting its availability for future

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availability for future Rate of depletion of non-renewable resources should be judicious Minimum adverse impact to the environment Maintaining equilibrium in eco-system.

SALIENT FEATURES OF MINING

PROSPECTING & EXPLORATION MINE DEVELOPMENT WASTE DISPOSAL DRAINAGE

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DRAINAGE TRANSPORT END USE OF MINERAL PRODUCED BENIFICIATION PRACTICE SITE SRVICES ENVIRONMENTAL MANAGEMENT POST MINING LAND USE

PROSPECTING & EXPLORATION

It is the most important exercise, to be carried out very

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exercise, to be carried out very faithfully because entire fate of future lies upon this

PROSPECTING vs. EXPLORATION

Prospecting is pre-mining stage operation mainly confines to

Exploration is a dynamic process & continues during subsistence of mining

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confines to establishing sufficient evidence of mineral occurrence in respect of shape, size, quantity, quality & economics

subsistence of mining period. It is expected it should lead ahead of mining operation for consistent updating the mineral reserve

It also should include

Identification of various litho-units occurring in & around the proposed mining site Establishing sufficient evidence of mineral

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Establishing sufficient evidence of mineral occurrence in respect of shape, size, quantity, quality & economics Correct assessment of geo-technical properties of rock mass including their toxic values.

CONCEPTUAL MINING PLAN

Long-term Perspective view of mining Time frame for assessing the true potentiality of area

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of area Visualization and determination of ultimate pit limit Waste disposal management Post-mining land use Ensuing mining operation are part of it.

MINE DEVELOPMENT

Selection of method of mining

Mode of Mining

Mechanized

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Opencast Underground Mixed

Mechanized Semi-mechanized Manual Conventional Non-conventional

OPEN CAST MINING

Precise assessment of optimum stripping ratio for amenability by open pit mining Determination of ultimate pit limit precisely

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Determination of ultimate pit limit precisely in advance Separate removal of top soil, mine-waste Advance removal of waste to avoid any possibility of interruption in work or ore dilution/contamination

OPEN CAST MINING continued….

Proper laying of mine faces for winning of different grades simultaneously to ensure judicious blending of ROM

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judicious blending of ROM Aiming to mine up to optimum depth Minimum mineral loss / dilutionSafe, secure & energy saving haul road

UNDERGROUND MINES

1. Selection & location proper mode of entry & exit i.e.Vertical shaft

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Vertical shaft Inclined Shaft Decline/Ramp Auxiliary/staple/ventilation shaft System of winding & access

UNDERGROUND MINES continued

2. Selection of proper method of work in relation to-Optimum recovery

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Optimum recovery Geotechnical properties of ore & wall rocks Adequate size of openings, blocks, pillars etc & long-term sustainability Complete width of ore body is to be worked Ensure least surface damage

MINERAL CONSERVATION

Waste should not be allowed to mixed with non-saleable fraction. Ground selected for waste disposal is to be

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Ground selected for waste disposal is to be proven for mineral occurrence and should be away from ultimate pit limit. Separate stacking of sub-grade mineral Judicious blending by different combination In case of underground mine, subgrade mineral is to be brought to the surface.

BENIFICIATION OPERATION

All attempts are to be made for up-gradation of low-grade mineral to make it saleable fraction.

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make it saleable fraction. Beneficiation Investigation are to be carried out Regular analysis of ‘feed’, ‘product’ & ‘tailings’

PLANT & MACHINARY

Selection of matching machinery to the mine design parameters & local conditions.

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parameters & local conditions. Optimum utilization Time & motion study Least waiting/idle time

PLANT & MACHINARY continue..

Energy saving & conformity to emission standards Attenuation of noise at the source

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Attenuation of noise at the source itself Dust suppression at the source of generation Planned preventive maintenance Minimum re-handling

BLASTING

Proper Blast design Optimum utilization of blast energy Desired fragmentation

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Desired fragmentation Neither under break nor over break Least ground vibration Least air blast Least fly rock Least nuisance attracting public annoyance Regular scientific investigation

SOLID WASTES GENERATED

MINE WASTES

Large in quantity

MILL/PLANT WASTE

Less in quantity

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Large in quantity Mostly inert Large in size- Solids Represents in-situ

Less in quantity Can be toxic Fine particles-Slurry Altered Product

ENVIRONMENTAL PROBLEMS

Leaching & wash off - heavy metals & toxic elements -acid mine drainage Dust pollution with toxic metals

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Dust pollution with toxic metals Phyto-accumulation of heavy metals Effect on vegetation & aquatic eco-system, Entry into food chain Effect on landscape

WASTE DUMP DESIGN

Height, area & shape with regard to the area available, topography & vegetation. Avoid Proliferation of dumps. Surfaces should be stable & resist long term

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Surfaces should be stable & resist long term erosion. Peripheral dumping, with simultaneous afforestation. Toxic waste dumps to be contoured and/or sealed to minimize water penetration. Potentially acid forming material to be sealed by inactive waste that has a buffering capacity.

WASTE DUMP DESIGN

Construction of drainage to handle heavy rainfalls. Topsoil scraped out from dumpsite in advance, to be preserved, spread over surface & re-

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to be preserved, spread over surface & re-vegetated. Provision of garland drains surrounding the dumps Provision of Retaining walls/Toe walls. Completed overall out-slopes do not exceed 20 degree Provision of benches/berms.

DUMP INSTABILITIES(Long-term instability)

REASON

Due to saturation

SOLUTION

Growth of

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Due to saturation with water & reduction in strength of

material due to water action.

Growth of permanent

vegetation over dump surface & establishment of proper drainage.

DUMP INSTABILITIES(short-term instability)

REASONPoor material strength, improper

SOLUTIONBenches, of heights not more than 10 to 15 m,

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strength, improper heights & slope angles. Long unbroken slopes produce rill & gully erosion

more than 10 to 15 m, with min. berm width of 4 m. Berm to have gentle slope, say 0.5%, towards high-wall side, with toe wall along periphery of dump.

Estimated relationship between the angle of dump slope and soil erosion & efficiency of re-vegetation

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VARIOUS TYPE OF DUMPS

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Management of Waste Dumps(Physical Stability)

ISSUESSteep slopes Unstable surfaces

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Unstable surfaces Erosion Drainage Dust Generation Hazardous waste Control

Management of Waste Dumps(Physical Stability)

Control MethodsSite selection Peripheral dumping, Retaining walls/Toe walls Internal drains & garland drain

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Internal drains & garland drain Gentle slopes & heights Berms, with rock-lined drains Cover & secure containment of hazardous waste, Cap with soil Settling ponds Vegetation along slopes Green barriers

Management of Waste Dumps(Chemical Stability)

IssuesMetal leaching Seepage

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Seepage Acid drainage Contaminants Effects on surface and groundwaterDump design

Management of Waste Dumps(Chemical Stability)

Control MethodsAnalyze the samples Isolation of reactive material No deterioration in groundwater

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No deterioration in groundwater Cap/enclose toxic material with inert & impervious material Control surface drainage & runoff Collect and treat effluent Cap with topsoil & vegetate Effective water management Monitor

Management of Waste Dumps(Land-use)

IssuesProductivity Visual impacts

Control MethodsMarketing/reuse of waste Back-filling Avoid dump proliferation

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Visual impacts Restore to original or accepted alternative use Establish land drainage

Avoid dump proliferation Design for minimum area Re-contour Establish vegetation Landscaping

Management of Waste Dumps(Biological Stability)

Issues

Re-vegetation Bio-diversity

Control Methods

Soil Fertilization/stabilization Planting leguminous plants

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Bio-diversity Survival of vegetation Phyto-accumulation of toxic & heavy metals Entry of toxic & heavy metals into food chain Development of self-sustaining plant community Forestry

Planting leguminous plants Draught resistant species Selection of Phyto-resistant species Successful re-vegetation with indigenous plants Protection for animal grazing Monitoring for soil quality Congenial environment for wildlife, with fodder & water

TOP-SOIL MANAGEMENT

Recovery is essential for rehabilitation work. Sooner it is reused the better the results will be.

Soil Stacks:

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Soil Stacks:Low heights, Should not get washed off Leguminous plants are to be cultivated In areas of poor soils, nutrient levels is low Fertilizer application is soil cheaper than soil stabilizers Single application will suffice in all areas except those prone to high soil leaching - eg over tailings

TAILING IMPOUNDMENT

Design requirements of dam & impoundment:Impoundment to be competent to support Not to be located in recharge zone, establishing hydraulic with aquifer

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Not to be located in recharge zone, establishing hydraulic with aquifer Relatively impervious, otherwise an impervious layer/dyke to be provided at bottom Foundation soil of the dam and the dam it self be competent to support & relatively impervious, otherwise internal drainage to be provided in side the dam Dam should have stable slopes- downstream slopes 1:3

Design requirements of dam & impoundment

Adequate drainage features to be provided As much as water must be re-cycled Conduits from decant towers passing below the

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Conduits from decant towers passing below the dam be avoided A floating or moveable pump hose located on the shore is better for water reclamation At each stage, dam raising should be fast to stay ahead of the rising tailings in the pond.

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Management of Tailing Impoundment(Physical Stability)

IssuesDam wall stability & foundation Dust generation

Control MethodsSite capacity & impervious Dam erected by competent rock Spillway/Adequate freeboard –1m Decant towers or floating pump

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Dust generation Erosion & Sediment deposit Dam drainage & Seepage Control on Phreatic line Overtopping of dam Earthquakes Access and security

Decant towers or floating pump Diversion of runoff to out side Stage-wise raising to be fast Tailing disposal Downstream Construction Final re-profile, Instrumentation Cap with soil & vegetate Plug intakes & decants

Management of Tailing Impoundment(Chemical Stability)

IssuesChanges in tailings geochemistry Metal leaching Acid drainage

Control MethodsLeaching tests Non-reactive material in dam wall Impervious layers- seepage Establish drainage within dam

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Acid drainage Mill reagents Dam structure Groundwater- seepage effect past the dam & from impoundment base Surface water management

Establish drainage within dam Control reactions Divert run-off Collect and treat effluent Acceptable water quality in downstream Monitor

Management of Tailing Impoundment(Land- use)

IssuesControl Methods

Re-contour to mach

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n Productivityn Visual impactsn Restore to accepted

alternative use

n Re-contour to mach surrounding landscape

n Provide soil capping n Provide sedimentation

tankn Establish vegetation

Management of Tailing Impoundment(Biological Stability)

IssuesRe-vegetation Bio-diversity Survival of vegetation

Control Methods

Soil stabilization Planting leguminous plants

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Survival of vegetation growth Phyto-accumulation of toxic & heavy metals Entry of toxic & heavy metals into food chain

Planting leguminous plants Indigenous species Draught resistant species Selection of species resistant to phyto-accumulation & concentration of toxic elements Protection of re-vegetated area against animal grazing Monitoring for soil quality & for phyto-accumulation

WATER QUALITY

Quantitative & Qualitative studies, for Surface & Ground Water characteristics

Available Site Water Sources Catchments area

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Catchments area Water Management & upstream pollution sources Maximum & Lean Rainfall Runoff rate at Peak Rainfall Potable Water Supply Sources, Quality & Quantity Domestic & Process Waste Water discharge Discharge points, Quality & Quantity

WATER BALANCE AT SITE

Lean season water availability Source tapped with competing users (River, Lake, Ground, Public supply) Changes observed in quality & quantity of ground water

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ground water Present recharging & extraction details Quantum of surface waste water to be released with treatment details Quantum of quality of water in receiving body, before & after disposal of waste/effluent Quantum of waste/effluent water released on land & type of land

Water balance diagram

Schematic diagram linking up flow of water to & from the facilities, Showing water supply source (s),

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Showing water supply source (s), Water discharge points), Evaporation areas & potential seepage points, with step wise indication of flow rates, in cum/day & quality, into & out of facility

Management of Water Quality(Physical Stability)

IssuesErosion, wash-off & sediment deposit Blockage in natural flow

Control Methods

Remove/restore unwanted structures, Fill in ditches Plug intakes & decants Upgrade flood design

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Blockage in natural flow Sewage & effluent treatment plants & sludge Discharge of drainage Structural Safety & flood capacity Intrusion of sea water Water balance, recharge

Upgrade flood design Reinstall pre-mining drainage Dispose plants & plant sludge Install check dams/settling pond Develop re-charge wells/holes Re-vegetate Install pre-mining water balance for mine area

Management of Water Quality(Chemical Stability)

Issues

Contamination of

Control Methods

Prevent/remove contamination of surface &groundwater with:-Acid drainage-Leaching of toxic metals

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Contamination of surface and /or groundwater Acid drainage Leaching of toxic metals

-Leaching of toxic metals Install new settling ponds Erect stopping or flood the pit Drainage - treat & discharge Install barriers/grout curtains Establish phyto-accumulant vegetation Monitor

Management of Water Quality(Land-use)

Issues

Interruption of water supply in catchment

Control Methods

Avoid interruption of water supply Establish erosion-resistant drainage

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supply in catchment area Productivity of land drainage Sediment deposition (Nalla sediments) Return to appropriateland use

Establish erosion-resistant drainage Restore drainage patterns or establish effective alternatives Install retaining walls Stabilize and maintain dam or breach Establish vegetation Establish effective rehabilitation

Management of Air Quality(Physical & Chemical Stability & Land-use)

IssuesWind Erosion Effect on vegetation

Control MethodsCap toxic & hazardous waste Remove or prevent contamination Land fill & capping

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Effect on vegetation Pollution of air with toxic substance Contamination of surface Productivity of land

Land fill & capping Establish vegetation Develop thick green barriers Monitor Establish erosion-resistant Structures Return to appropriate land use or establish alternatives

Monitoring of Water & Air Quality

To demonstrate remedial/ restoration work is successful. To meet closure objectives &

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To meet closure objectives & performance criteria. To compare results with earlier monitoring data. Monitoring for dry season, as per IBM/MoEF norms. Climactic data also to be coupled

RECLAMATION & REHABILITATION

Creation of adequate green belt in and around mining lease areaIt gives a green curtain is to be set against all scars i.e. excavation, dumps etc and

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all scars i.e. excavation, dumps etc and improves aesthetic sense of the area It effectively arrests all the dust generated from mines It effectively attenuate unpleasant noise Lessens the adverse effect of green house gas emission

RECLAMATION & REHABILITATION continued….

Incase of availability of mine waste, voids are to be filled back & efforts are to be made to bring them near

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are to be made to bring them near original shape Incase of partial availability of waste, possibility of part reclamation is to be thought. Remaining voids can be converted as water reservoir

RECLAMATION & REHABILITATION continued….

n Possibility of filling by fly ash or other waste material available nearby is also to be thought but a prior study thereof is also

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be thought but a prior study thereof is also to be undertaken for any apprehended adverse impact on water regime

n In case of shallow excavations, quarry floor plantation is to be undertaken along with adequate drainage arrangement

RECLAMATION & REHABILITATION continued….

Incase of arid regions, converting the pits as water reservoir is best post mining land use. But its slope

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post mining land use. But its slope should be adequate & should also act as shield against drowning. Incase of hilly terrain dense plantation is to be undertaken on finalized bench.

Mankind should learn the correct way of enjoying the natural wealth from the Honeybee as they continue to

Conclusion:

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the Honeybee as they continue to collect Honey from the flowers without causing any detrimental impact or deformation to the nature’s beautiful gifts.