Removal of valuable minerals from the earth by taking both people and equipment into depths from the earth’s surface is called underground mining.Unsupported openings, Supported openings and Caving methods are the three methods of underground mining. Main methods in Underground mining are drift mining, slope mining, shaft mining, borehole process and hard rock mining.Contamination of rivers, lakes and ground water, alteration of surface and ground water flow, erosion and instability, loss of soil, material contamination, improper sanitation, increased dust, loss of faunal and floral habitats, over use of timber resources and destruction of forests and savannah are the general environmental threats of mining. Gem 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. Damage to vegetation cover, plantations and paddy fields, damage to land and geomorphology, man-made structures, to streams and river banks, sedimentation and water pollution, damage to fauna, alteration of surface and ground water flow and adverse environmental health conditions are some threats of gem mining. Graphite and gold mining also have a severe impact on the environment. Especially the impacts are affecting on soil and water. Backfilling of mined sites, seeding with grasses, tree planting at backfilled sites with native species, shaping and contouring of spoil piles and replacement of top soil are some mitigatory measures to the land reclamation after the mining of gold, gem and graphite.

1. Environmental Threats & Land
Reclamation
on Underground Mining
Pabasara Gunawardane

2. • Underground Mining
• Land Reclamation
• General Threats
• Gem Mining
• Graphite Mining
• Gold Mining
Contents

3. 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

4. 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

5. Contamination of rivers , lakes and ground water
Alteration of surface and ground water flow
Erosion and instability
Loss of soil
Material contamination
Improper sanitation
Increased dust
Loss of faunal and floral habitats
Over use of timber resources
Destruction of forests and savannah
General Environmental
Threats

6. Gem mining

7.  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

8. Source: Dissanayake and Rupasinghe; Gems and Gemology, 1993
Gem deposits
of Sri Lanka

9.  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

10.  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

11.  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

12.  Digging of adits under roads,houses,
irrigation channels, culverts etc. cause
damage to man made structures.
(Ratnapura, Elahera, Matale)
Damages to man-made structures

13.  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

14.  Release suspended solids in large quantities into the
water.
 Acutely reduce the carrying capacity of waterways and
dams.
Sedimentation and water pollution

15.  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

16.  Rivers and lakes are diverted.
 Ground water tables lowered due to unstrained pumping of wat
Alteration of surface and ground water flow

17.  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

18.  Backfilling of mined sites
 Seeding grasses and tree planting at
backfilled sites
 Constructing river embankments
 Replacement of top soil
 Relocate streams and faunal species
Land reclamation practices

19.  Traditional gem mining techniques combined with new
technology.
Environmental friendly gem
mining in sri lanka

20.  Mechanized gem mining

21. Rehabilitation of mined sites and reconstruction
of damaged river banks

22. Graphite mining

23.  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.

24. Bogala
Graphite
Deposit

25. Kahatagaha mine

26.  Landslides
 Alteration of water table
 Increased dust
 Soil contamination
 Damage to fauna & flora
 Disturbs to water cycle
 Erosion and instability
Environmental threats

27.  Ground water tables lowered due to unstrained pumping of
water.
Alteration of water table

28.  Lack of top soil due to wind erosion.
 Desiccation of land.
Increased dust

29.  Occurs due to discharge of sediments into hydrological
environment.
Soil Contamination

30.  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

31.  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

32. Gold mining

33.  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.

34.  Water contamination
 Accumulation of toxic waste
 Solid waste
 Acid mine drainage
 Damage to fauna and flora
Environmental threats

35.  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

36. Making Mines
Environmentally Friendly
Better legislation and regulations
Scrap mining and recycling
Closing illegal and unregulated mines
Closing and reclaiming sites of shut-down mines
Investing in research and development of Green Mining Technology
Replenishing the environment

37.  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 Lanka
References

38. Thank You