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