Environmental threats and Land Reclamation on underground mining of Gem,graphite and gold
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Transcript of Environmental threats and Land Reclamation on underground mining of Gem,graphite and gold
Environmental Threats & Land Reclamation
on Underground Mining
Pabasara Gunawardane
• Underground Mining
• Land Reclamation
• General Threats
• Gem Mining
• Graphite Mining
• Gold Mining
Contents
Removal of valuable minerals from the earth by taking both people and equipment into depths from the earth’s surface.
Underground mining methods Unsupported openings Supported openings Caving methods
Main methods in Underground mining• drift mining• slope mining• shaft mining• borehole process• Hard rock mining
Underground Mining
Land reclamation is the gain of land from the sea, or
wetlands, or other water bodies, and restoration of
productivity or use to lands that have been degraded by
human activities or impaired by natural phenomena.
(Glossary of Environment Statistics, 1997 )
Land Reclamation
Contamination of rivers , lakes and ground waterAlteration of surface and ground water flowErosion and instabilityLoss of soilMaterial contaminationImproper sanitationIncreased dustLoss of faunal and floral habitatsOver use of timber resourcesDestruction of forests and savannahGeneral Environmental Threats
Gem mining
Gem mining is the process of extracting the natural resource, gems
Traditional methods, mechanical and semi-technological methods are used in mining process.
Mining methods range from digging deep mines and adrift to shallow open mining and river bed mining.
In Sri Lanka traditional gem mining is mainly found in Balangoda, Ratnapura, Opanayake, Deniyaya, Rakwana, Elahera and Matale areas.
Legislation to minimise environmental damage caused by gem mining is included within the 1971 Act drawn up by the NGJA, reinforced by the Mines and Minerals Act of 1992
Source: Dissanayake and Rupasinghe; Gems and Gemology, 1993
Gem deposits of Sri Lanka
Damage to vegetation cover, plantations and paddy
fields
Damage to land and geomorphology
Damage to man-made structures
Damage to streams and river banks
Sedimentation and water pollution
Damage to fauna
Alteration of surface and ground water flow
Adverse environmental health conditions
Environmental threats
Due to complete uprooting of the vegetation
associated with the mining.
For the purpose of ‘Construction’ or reinforcement
of the walls of mines in the inhabited areas, tree
species are used. As a consequence paddy fields in the lowland areas
in Ratnapura and the Southern Province have become gem bearing lands, caused damage to paddy fields and croplands.
Damage to vegetation cover, plantations and paddy fields
Large pits and many huge mountains of soil that
have been dug out are a common sight. (Polwatta,
Matale)
Infertile sub soil dug up during mining are
physically unstable and subjected to erosion by rain
water causing damage to the surrounding
vegetation. (Raththota, Matale)
Damage to land and geomorphology
Digging of adits under roads,houses, irrigation channels, culverts etc. cause damage to man made structures. (Ratnapura, Elahera, Matale)
Damages to man-made structures
Collapse of river banks into the water, is caused
by the digging of alluvial deposits for gems.
(Amban-Ganga and Elahera areas)
Damage to streams and river banks
Release suspended solids in large quantities
into the water.
Acutely reduce the carrying capacity of
waterways and dams.
Sedimentation and water pollution
Large scale addition of very fine clay particles
to water increases the turbidity of the water.
Leads to less light penetration causing an
environmental imbalance in the rivers and
steams.
This leads to a decrease in photosynthesis and
thereby inactivates the food relationships.
Damage to Fauna
Rivers and lakes are diverted.
Ground water tables lowered due to unstrained pumping of
water.
Alteration of surface and ground water flow
Because refilling of the pits after the mining is not carried out in the proper manner, carriers of diseases such as mosquitoes increase in numbers.
The spread of malaria due to the increase in numbers of mosquitoes in the abandoned water filled mines is a major health risk.
The risk of mammals, reptiles and also human beings falling into these unfilled pits is another problem.
Adverse environmental health conditions
Backfilling of mined sites
Seeding grasses and tree planting
at backfilled sites
Constructing river embankments
Replacement of top soil
Relocate streams and faunal speciesLand reclamation practices
Traditional gem mining techniques combined with new technology.
Environmental friendly gem mining in sri lanka
Mechanized gem mining
Rehabilitation of mined sites and reconstruction of damaged river banks
Graphite mining
Graphite is made almost entirely of carbon atoms. Most stable form of carbon under standard
conditions. Graphite occurs in metamorphic rocks as a result of
the reduction of sedimentary carbon compounds during metamorphism.
Graphite mining is the process of extracting the natural resource, graphite.
In Sri Lanka Bogala and the Kahatagaha are the main graphite deposits.
Sri Lanka is the only country in the world where crystalline graphite or lump(vein) graphite is mined underground.
Bogala Graphite Deposit
Kahatagaha mine
Landslides
Alteration of water table
Increased dust
Soil contamination
Damage to fauna & flora
Disturbs to water cycle
Erosion and instability
Environmental threats
Ground water tables lowered due to unstrained pumping of water.
Alteration of water table
Lack of top soil due to wind erosion. Desiccation of land.
Increased dust
Occurs due to discharge of sediments into
hydrological environment.
Soil Contamination
Loss of flora and fauna species due to
deforestation, landscape destruction.
Finally more arid or barren lads will be the result.
Damage to fauna & flora
Backfilling of mined sites
Seeding with grasses
Tree planting at backfilled sites with native
species
Shaping and contouring of spoil piles
Replacement of top soil
Land Reclamation Practices
Gold mining
Gold mining is the process of mining of gold or gold ores from the ground.
Methods of gold mining are placer mining, panning, sluicing, dredging, rocker box, hard rock mining.
Pascua Lama gold-mining project in northern Chile threatens one of the richest farming valleys in the region of Atacama.
The project endangers three glaciers, an important source of water for the valley’s farmers.
Water contamination
Accumulation of toxic waste
Solid waste
Acid mine drainage
Damage to fauna and flora
Environmental threats
Backfilling of mined sites
Seeding with grasses
Tree planting at backfilled sites
Shaping and contouring of spoil piles
Replacement of top soil
Relocate streams and introduction of
faunal species
Land reclamation practices
Making Mines Environmentally Friendly
Better legislation and regulations
Scrap mining and recycling
Closing illegal and unregulated mines
Closing and reclaiming sites of shut-down minesInvesting in research and development of Green Mining Technology
Replenishing the environment
Glossary of Environment Statistics, Studies in Methods, Series F, No. 67,
United Nations, New York, 1997.
http://rukshanmaliq.blogspot.com/2011/12/unseen-side-of-graphite-
mining.html
http://nodirtygold.earthworksaction.org/action#.U3nUF9KSySo
Rupasinghe, M. The gem industry in Sri Lanka and its environmental
impacts.
Suzuki, D. 2010. Environmental Stewardship in gemstone mining: Quo
vadis?
Henney, P. 1999. Sri Lanka National Factsheet.
Alagan,R. Sri Lanka’s environmental challenges.
Dharmaratne.P.G.R, 2013, Evaluation of Overhand Cut and Fill Mining
Method used in Bogala Graphite Mines, Sri LankaReferences
Thank You