Major Areas :: Disaster Management

Slope Stabilization-Ecological Restoration of Mine spoils

Dumping of mine spoil

Mining occupies a pivotal position in India, currently meeting over 60 per cent of the country’s commercial energy requirement and thus become increasingly recognized engine of development. An around 0.8 million hectare of land is under mining affecting local environment drastically.
Surface mining is spread over to about 5000 ha at Neyveli Lignite Corporation Limited (NLC), Neyveli. The spoils of the first excavated mines are spread over an area of 300 ha. The slopes of these dumps, left as such over years have undergone erosion changes and currently present an environmental hazard and un-aesthetic outlook.

PINNACLE FORMATION DUE TO EROSION

Landslide has been common on steeper slopes of mine spoil overburdens leading to pinnacle development of various steepness and depth during the monsoon rains resulting in unstable slope formation.
Attention must be given to control erosion on larger dumps and to stabilize the slopes. One way to reduce erosion is use of biological methods by creating diverse vegetation as soon as possible.

Rehabilitation of such degraded slopes with pinnacles is a challenging task and this issue has to be addressed scientifically.
A comprehensive mine spoil slope rehabilitation plan should be drawn based on research on the utilization of available natural resources, which includes compaction to stabilize the mine spoil slope, shaping of mine spoil pinnacles into slopes and terraces and greening the slopes.

TNAU INTERVENTIONS
In this context, a collaborative research project was planned between Tamil Nadu Agricultural University (TNAU), Coimbatore, and Neyveli Lignite Corporation (NLC), Neyveli, to reclaim and rejuvenate degraded mine spoil slopes at NLC.Neyveli during the period of 2004-2008.

The slope stabilization technologies, bioengineering measures and revegetation of pinnacles at lignite mine spoil ecosystem were evaluated with the following components in an area of 30,000 m2 (300 m length and 100 m depth) at Mines Neyveli Lignite Corporation Limited, Neyveli.

Evaluated the influence of Rainwater harvesting techniques viz., Micro catchments, Ridge and furrows, Half moon terracing, Inward slope bench terraces on establishment and growth of tree species.Developed suitable pre-sowing seed management technologies such as dormancy breaking treatments, hydro priming and pelleting for establishment and growth of fodder, shrubs and tree species.

Established suitable Mulching techniques and erosion control measures viz., the use of Wood chips, Industrial solid wastes (coir waste, press mud, flyash, sewage sludge etc.,) in terraces and micro catchments for sustaining tree growth and for their positive influence of soil health. Evaluated the positive influence of bio-fertilizer and organic amendments like green manure, Industrial solid wastes and other natural organic materials available around NLC for sustaining the mine spoil health.

Established Identified plant species in the terraces and batters of slopes

Restored mine spoil

Slope stabilization technology is highly suited to protect the slope structure from soil erosion, which in turn ensures eco health and stability to the mined area.
The mining industries easily get environmental clearance for further activities of mining.
The aesthetic value of the degraded system is improved for which the real value and benefit cost cannot be assessed.

Source:
Professor and Head,
Dept. Environmental Science,
TNAU,
Coimbatore
Phone No: 0422 -6611252

Updated on March, 2015