Environmental Threats and Reclamation after Underground

Mining: Specially focus on Gem mining

R.M.T.D. MadusankaAS2012135

1. Underground Mining.2. Gem mining.3. Gem mining areas.4. Gem mining methods.5. Pit mines.6. Environmental threats of gem mining.

Threats on water.Threats on soil.Threats on fauna and flora.Threats on humansThreats on Landscapes.

7. Mine Reclamation.8. Gem mine Reclamation.9. Conclusion.

Content.

MiningThe activity, occupation, and industry concerned with the

extraction of minerals.Underground Mining

Mineral exploitation in which the extraction is carried out beneath the surface of the earth

Types of Underground mining.• Drift mining.• Slope mining.• Shaft mining.• Borehole process.• Hard rock mining.

Underground Mining.

• Graphite Mining.

Underground Mining in Sri Lanka.

• Gem Mining.

Gem Mining.

Gemstone mining is a traditional industry in Sri Lanka runs way back to the era of ancient kings.

Even today traditional mining is the most common practice.

(more than 6,500 licenses issued in 2013, more than 6,000 were for pit-mining operations using traditional methods)Currently Gem mining is under the regulatory

supervision of the NGJA.A gradual rise in the use of light mechanized mining

methods can also be seen in recent times.Illegal exploitable gem mining is also increased in

recent times.

Traditional gem mining areas• Ratnapura • Pelmadulla• Balangoda,• Eheliyagoda • Rakwana.

Gem Mining Areas.

Recently extended areas• Elahera• Bakamuna• Passara• Okkampitiya• Kanthale• Bibile• Horana

Gem Mining Methods.

Gem Mines.

Pit Mines.

Shallow Pit Mines.

Deep Pit Mines &

tunneling

Riverbed Mines.

Shallow circular pits.• When Gem deposits are located

near the surface.• Depth of a shallow pit can be only

few meters.

Deep rectangular pits.• May have a depth of over 50 meters.• Excavated horizontally creating

tunnels extend from 6 to 9 meters

Pit Mines.

Environmental Threats of Gem Mining.

Water

soil

Flora & Fauna

Humans

Landscape

1. Contamination of rivers, lakes and waterbodies.

Causes• Discharge of muddy water , sediments, rubbish into hydrological environments.• Washing of gem bearing soils in streams.

Long-term consequences• Reduce the reservoir capacities . • Floods.• Turbidity and salinity levels have effects on fauna and flora. .

Threats on Water.

1. Contamination of rivers, lakes and waterbodies.

Mitigation Strategies• Mud filtering systems can be introduced.

-Sediment tanks -Slit traps

Threats on Water.

2. Alteration of surface and ground water flow.Causes• Unrestrained pumping of water for mining activity.• Diversion of streams from the mining area.

Long-term consequences• Depletion of groundwater levels .• Altered flooding patterns are.• Unavailability of water for agricultural purposes.

Threats on Water.

2. Alteration of surface and ground water flow.

Mitigation strategies• Re-diverting the streams following the cessation of

mining. • Regulating the excessive pumping of water.

Threats on Water.

1. Soil erosion and Instability.Causes• Pilling of easily erodible subsoil in the surface. • Mining in stream banks.Long-term consequences• Siltation in streams & reservoirs.• Collapsing the stream banks.Mitigation strategies• Covering the piles of soil.• Effective law enforcement.

Threats on Soil.

2. Loss of soil nutrition.Causes• Bringing up the infertile sub soil in to the earth surface.• Washing the soil in searching gems.

Long-term consequences• infertile soil• Depletion of agricultural production.

Mitigation strategies• Limit damage to topsoil in the mining• Remediate appropriately post-mining.

Threats on Soil.

1. Loss of faunal and floral habitats Causes• Deforestation. • Complete uprooting of vegetation.

Long-term consequences• Biodiversity loss.

Mitigation strategies• Conserve the similar habitats.• Regulate the behavior of labours.

Threats on flora & fauna.

2. Overuse of timber resources.Causes• Reinforcing mining pits(Rubber & Arecanut)• Mine sheds.(Bamboo, Arecanut)

Long-term consequences• Depletion of timbers in the market.• Depletion of Arecanut production.

Mitigation strategies• Introduce Replanting of timber species.• Use other common timber species.• Reuse where appropriate.

Threats on flora & fauna.

1. Contaminated water sources.Causes• Muddy water from the mines.

Long-term consequences• Depletion of drinking water sources.• Health problems for humans.

Mitigation strategies• Introduce filter systems.

Threats on Humans.

2. Safety hazard of pits during and after mining.Causes• Improperly constructed pits. • Improperly ceased pits.• mine collapse.• Gas poisoning.

Long-term consequences• Malaria, Dengue.• Respiratory and skin diseases.• Deaths.

Threats on Humans.

2. Safety hazard of pits during and after mining.Mitigation strategies• Reinforcing pit walls.• Pits and shafts should be closed properly after mining has ceased.• Use of safety wears.• Aerate the deep mines.• Pre-identification of possible gas poisonings.

Threats on Humans.

3. Land-use conflicts.Causes• Mining activities conflicts with livelihood activities. (Paddy cultivation, plantations)

Long-term consequences• Social and economic Problems.

Mitigation strategies• Improve stakeholder participation in planning mining activities.

Threats on Humans.

4. Damages to the man made structures.Causes• Digging in roadsides• Depletion of water table by pumping of water.

Long-term consequences• Cracking the soil and walls of houses.• Erosion of roads.

Mitigation strategies• Set the limits for dewatering mines.• Law enforcement.

Threats on Humans.

1. Landscape destruction.Causes• Constant pitting and trenching.

Long-term consequences

• Unstable deteriorated landscapes.

Mitigation strategies

• Pits must be reclaimed properly after mining.

• Regulate the mechanized mining.

Threats on Landscapes.

Reclamationof

Gem Mines.

Mine reclamation is the process of restoring land

that has been mined to a natural or economically

usable state.

After any mining activity landscapes are altered and the

ecosystem totally disrupted.Two options in reclamation,

• Restoring the pre-mining land use.• Change the land use to another.

Mine Reclamation .

The first task in developing an effective mine reclamation

program is to set a clearly defined post-mining land use

objective.

• It should be compatible with surrounding land use.

• It should support biodiversity.

• It should be consistent with the expectations of the local

community and the landowners.

• Regulatory agencies must agree with it.

Mine Reclamation .

For the most Gem mined area, restoration of the pre-mining land use is the best suited method. Because, • most of gem mines are in the paddy fields, forested

areas and stream banks.• Permanent alteration of those land uses is not accepted.

Gem Mine Reclamation .

Reclamation plans should implemented as soon as areas

become available.

The disturbed mined areas need to be returned to a safe

and stable physical state.

• Pits should be closed.

• Soils are stabilized.

• Risks to humans, domestic animals and wildlife minimized.

Physical Reclamation .

Then suitable vegetation can be established or facilitate the

natural succession.

Outcome will be,

• Restoration of habitats.

• Conservation of soil.

• Increase the productivity.

• Restore the scenic value.

Ecological Reclamation .

About 90% of the gem mining is carried out in alluvial

deposits using traditional methods.

Despite the relatively high economic and social benefits

gem mining cause significant environment damages.

The damage on the environment from the industry is

gradually rising with the illegal gem exploitation and the

recently introduced mechanized methods for mining.

Conclusion .

• National Gem And Jewellery Authority Act No 50 of 1993.• Mines And Minerals Act No 33 of 1992.• Guild lines for natural resource management, CEA • Rehabilitating mines to meet land use objectives: bauxite mining in the jarrah

forest of Western Australia by J. Gardner• MEASURES TO REDUCE ENVIRONMENTAL IMPACTS OF GEM MINING D.K.N.G.

Pushpakurnara' and H.C. Panditharathna/ • CAN TRADITIONAL METHODS BE STILL USEFUL IN EXPLORATION AND MINING OF

GEM DEPOSITS? - A REVIEW , S.W. NAWARATNE• Environmental Stewardship in Gemstone Mining by David Suzuki.• http://www.fao.org/docrep/004/y2795e/y2795e03.htm• Official website of Geological survey and Mines bureau

http://www.gsmb.gov.lk/• Official website of National Gem and Jewellary Authority http://

www.ngja.gov.lk/en/q

References.