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ENVIS Technical Report 80,   October 2014

Reclamation of Mine Regions at Bisgod: Approaches and Challenges

Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012
*Corresponding author: cestvr@ces.iisc.ernet.in, energy@ces.iisc.ernet.in [080-22933099]
Executive Summary
  • Regional mine development plan to be developed only  after an assessment of carrying capacity of a region. This should include local infrastructure capacity, number and type of mining leases in an area; beneficiation requirements, prevalent mining methods; ore transportation alternatives, management of top soil, mine closure plan, etc.
  • Regional strategic plan to include environmental, ecological and social impact issues and drive the internalization of their associated mitigation costs (eg., mine waste management; conservation, protection and development of water and ecological resources; regional social issues etc.). This includes focus on conservation of biodiversity, ecology and hydrology of a region.
  • Assessment of cumulative impacts and setting threshold limits at local levels.
  • Recovery of an ecosystem (that has been degraded or destroyed) through ecological restoration, involving restoration of the stability and productivity of land to enable regrowth of vegetation. Reshaping of the 2 to 5 m high pit walls to a maximum slope angle of 20º. In order to improve the stability of the area, a minimization of slope inclination to < 30% is required. Broad terraces (8-12 m width) and small terraces (1.2 m width) would help in addressing erosion hazards.
  • Need to restore the land to its approximate original contour. In open-pit mining area, the mining steeps are to be flattened with the provision of drainage channels with retaining walls avoids the soil erosion.
  • Topsoil of the study area is very poor in nutrients, with low content of clay and medium organic matter and very alkaline. Need to maintain over 25 cm in order to support effectively the established species. Also, the topsoil should be enriched with organic matter (2% at least) in order to improve soil fertility. The organic materials nourish degraded soil are to be enriched with nitrogen fixing bacteria (Rhizobium, Azotobacter) and endo-mycorrhizal fungi.
  • Organic wastes aid as both fertilizers and soil amendments. The most practical way to increase the nitrogen content of ecosystems is to establish nitrogen fixing plants such as, legumes (Horse gram Macrotyloma uniflorum immediately after first showers)  and use of these plants as mulch later.  
  • Top soil of the region need to be handled carefully during mining and use of top soil during the rehabilitation of mined regions will help in rejuvenation of the region.
  • Plant the native species of early successional species of herbs and grasses- planting early succession species of native herbs and grasses would help in improving soil quality. The important grass species, namely, Bothriochloa pertusa, Chrysopogon fulvus, Cymbopogon flexuosus, C. martinii, Cynodon dactylon, Dichanthium annulatum, Eleusine indica, Heteropogon contortus, Saccharum spontaneum, etc.,  may be planted in  the region including slips and root stocks.

Table 1: Grass species suggested for re-vegetating degraded landscapes

Sp

Inclusion

Remarks

Bothriochloa pertusa

Yes

It is able to grow in many types of soils. It withstands drought and disturbance, and it can sprout up in dry, degraded habitat, such as roadsides. It survives short-term water logging and fire

Chrysopogon fulvus

Yes

Considered a useful pasture grass and has been used to enrich degraded grasslands. Grazing is to be avoided during the establishment year. Palatable and fairly high-yielding

Cymbopogon flexuosus

Yes

also called Cochin Grass or Malabar Grass is a perennial grass native to India, Sri Lanka, Burma, and Thailand. It is placed in the genus Cymbopogon (lemon grasses). Grown in moist, full sun to partial shade

C. martinii

Yes

Similar to above

Cynodon dactylon

Yes

 

Dichanthium annulatum

Yes

The grass can also be used to revegetate degraded grasslands. It is a very effective binding plant for erosion control. This is favored pasture grass species in India.

Eleusine indica

Yes (in moist areas)

It grows in moist as well as marshy areas, puddles, shallow ponds, fields, river and stream edges, ditches, canals etc. It is tolerant of heavy disturbance like trampling, organic pollution and can grow along sewage lines, gutters easily

Heteropogon contortus

Yes

Valuable pasture species. Favoured in most environments by frequent burning.

Saccharum spontaneum

Yes (needs initial moist conditions)

Occurs along river banks; usually in sheltered places. It grows as wasteland weed. It is considered as valuable medicinal herb in traditional systems of medicine in India. Planted to check soil-erosion

  • Reclamation of mined out areas is a challenging task due to altered chemical and physical trait of the region. In the initial stages of reclamation quick growing grasses with short life cycle will improve the nutrient and organic matter content in soil. Plantation of mixed species of economic importance could be done after 2-3 years of growing grasses. Cover the area with a loose layer of hay mulch to provide the initial "jump start" of forage required for the livestock.
  • Use of microbial activator or a mixture of microorganisms and organic matter will aid in increasing soil organic fertility and productivity. 
  • Mining activities are unsustainable not only because they exploit non-renewable resources, but also because they leave behind degraded landscapes to the society. Large scale mining should be banned in ecologically sensitive regions – Western Ghats. 
  • Address the needs of all stakeholders including miners and local community during pre and post mining periods.
  • There is a need to strengthen grassroots administrative structures especially gram panchayaths to address the issues related to mining  fitting into existing communities to cooperate with the local communities to improve the region for a meaningful contributor to sustainable development.
  • Post project monitoring committee: Empowered multi-disciplinary committee comprising of mining engineer, civil engineer, hydrologist, ecologist, wildlife biologist, village forest committee members, local forest officers and representatives of the affected communities would help in administering the restoration of the region especially stabilization of slopes, re-establishment  of vegetation, lowering of silt yield and transport, enrichment of habitats of endemic fauna, etc.
  • The forestry as the future land use of the mining area as the previous land use was predominately forests (includes degraded forest land, used for animals grazing and firewood production)
  • Monitoring of afforestation activities and submission of yearly reports regarding survival status of saplings in coordination with forest department.
  • Afforestation practices help in restoring and enhancing the vegetation cover in mine areas in various ways. Reclamation through afforestation with native species requires inventories such as area to be planted, native species of the region, slope gradient, quality of soil, climate conditions and nature of biotic pressure in the mining sites, overburden sites and abandoned sites. Those species have to be selected which have  ecological supremacy in enhancing soil moisture, maximum canopy in short time as well as hard woody and ability to fix direct atmospheric nitrogen.
  • Instead of dense Acacia auriculiformis planting in mine pit areas, mix of native forest species such as Terminalia sp, Aporosa lindleyana, Lagerstroemia lanceolate, Diospyros montana, Syzygium cumini, Olea dioca, Buchnania lanzan, Venguria spinosa, Randia dumentorum, Careya arborea, Schleichera oleosa, Adina cordifolia etc., is to be practiced to improve the soil quality and fertility. Introduction of nitrogen fixing trees such as Albizia sp, Cassia fistula, Xylia xylocarpa and addition of biofertilizers such as Azotobacter, Rhizobium, and endomycorrhizal fungi would enable the plant species to be stress tolerant through continuous supply of nutrients during early stages of growth.
  • The species that survive in varied habitats such as Sapindus emarginatus, Mangifera indica, Artocarpus heterophyllus, A. lakoocha, Garcinia indica, Ficus spp., Terminalia bellirica, Caryota urens, Madhuca indica, Pongamia pinnata, Corypha umbraculifera, Aegle marmelos, Bombax ceiba, Phyllanthus emblica etc. will aid as shade trees, utility trees (fruits, medicine, fodder leaves etc.) and habitat for nectar species, with varied ecosystem services.
  • The cattle-proof trench (CPT) is required to prevent cattle browsing and encroachments in forest regeneration areas.
  • An alternative to improve soil quality of degraded lands in Bisgod region is the establishment of forest with the mix of native species, which improve ecosystem services such as: litter supply, nutrient cycling, water infiltration, control of erosion, and increasing of biodiversity. This process allows the soil exploration by abundant root system, the protection of the soil surface against erosion, and the reactivation of nutrient cycling via litter production and decomposition.
  • Provision of LPG cylinders to all households and alternate energy devices such as biogas to minimize the dependence on forest wood for domestic cooking, water heating, etc.
  • Post mine environmental monitoring and management groups’ (of the affected communities) active involvement in rejuvenating the region by afforestation, development of native species nurseries, nurturing of sapling during initial stages, etc.
  • Village Forest Committees of Bisgod and NGOs, self-help groups that are environmentally conscious to be involved in planning of recovery of native vegetation. The programme of raising seedling by the local women and  unemployed youth would empower local population.
  • Existing Acacia plantations are to be replaced with native vegetation in phased manner and the revenue generated be used for afforestation endeavours.
  • Forest plantation establishment is broadly divided into three management phases such as, seed collection and handling; nursery practices and plantation establishment; and management. The forest department should make VFCs and local women as an active partner of plantation, management.
  • Improved regulations and independent monitoring teams should be commissioned to provide moral as well as monetary support to local communities through VFCs.
  • The abandoned mined sites (acting as a lakes) in the villages of Nagarakan, Hukkalli, Bale Kodlu to support rainwater recharge and aid as food and water resources for wild animals as well as local people.
  • Some mined sites are already acting as a water bodies and has water throughout the year, which should be provided with stone pitching to reduce the degradation of surface water bodies in monsoon. Construction of diversion channels, protective earthen bunds and check dams at appropriate locations to minimize sedimentation in surface water bodies.
  • The overburden needs to be managed separately and stockpiled nearby. Reuse of these as cover for the mine region will help in the direct return of fresh topsoil which enhances the possible return of viable seeds, nutrients, organic matter and beneficial soil micro-organisms.  
  • Forest fragments close to the degraded areas are important sources of seeds and these fragments needs to be preserved and monitored to sustain natural resources.There is an urgent need for creation of grassy patches in Garel, Bisgod region to reduce the grazing pressure on forests. The vacant staff quarters (Figure 14) of mining agencies should be handed over to the use of forest department, local schools or VFCs.
  • Mining company are required to deposit with IBM at least 15% of annual revenue (or based on the spatial extent of mines or quantity mined very year). This money deposited with IBM, be used for restoration of the region during the post mining period. This has distinct advantage over financial assurance concept, every year as the fund increases making it viable and substantial in the end of life.
  • In this regard, State Government can conduct the survey of abandoned mines, prepare project report in consultation with IBM for assessment of fund for reclamation and rehabilitation activities for further monitoring and commission preparation of reclamation projects in consultation with local committees to be executed by District Mineral Foundation out of State Mineral Funds as per proposed MMDR2011.
  • Provision of financial surety would guarantee the reclamation costs at the time of abandonment of mines. Therefore, the financial surety should come into active force if the mining agencies fail to meet the standard regulations of reclamation at the time of abandonment, technical and financial failure or in the event of premature closure. The recommendations and representation of VFC is provided in Annexure-1.

The Central Pollution Control Board (CPCB), Ministry of Environment and Forests, Government of India, has initiated a study entitled “Description of Clean Technology for Iron Ore Mines and Development of Environmental Standards ” provides the following guidelines for reclamation.

  • The mined land is to be cleared of rubbish, surplus materials, temporary structures and equipment and all parts of the land shall be left in a condition as close as possible to that prior to use.
  • Topsoil should be replaced along the contour where possible. This will help in erosion control by reducing water flow down slope and increasing water storage. Wherever possible, the topsoil should be immediately replaced on an area where the land form reconstructions are complete.
  • If topsoil is not available, the cost of transporting is prohibitive, or the topsoil contains such high levels of week seed or plant pathogens that it is unsuitable for rehabilitation, then subsoil, overburden, waste rock or similar materials must be used as a substrate for re-vegetation.
  • The following are techniques which can be considered to improve the ability to support plant growth in the long term  
  • Application of organic matter such as animal manures, sewage sludge or other wastes; chemical amendments such as Gypsum to improve the structure and reduce the pH of highly alkaline substances. Lime to raise the pH of acid substrates and inorganic fertilizers.
  • Soil conditioners such as growing green manure crops help in the faster reclamation.
  • Mulches can be used to protect the soil from raindrop impact. Most suitable materials are brush matting, stubble mulch; lazy mulch, sawmill wastes, bitumen, and other chemical stabilizers. These materials may also aid, or in some cases inhibit, germination of seeds in the revegetation program.
  • Native planting is the key to successful rehabilitation. Plant species can be established on rehabilitated areas from propagules (seeds, lignotubers, corns, bulbs, rhizomes and roots) stored in the topsoil or sowing seeds (seed retained on the plant in persistent woody capsules) onto areas being rehabilitated, planting nursery-raised seedlings; habitual transfer – the transfer of substantial amounts (around 1 m to 200m).
  • Species which have similar growth forms to the original vegetation, and thrive in areas with comparable soil types, drainage status, aspect and climate of the rehabilitated area, are the most appropriate. Care must be taken to avoid introducing a species which could become an unacceptable fire hazard, invade surrounding areas of native vegetation or become a weed for the local agriculture.
  • Tailing dams/ ponds should be redesigned with decant tunnels, channels to provide for storm water run-off.
  • Re-vegetation of exposed surfaces shall be done as far as possible in mines. Techniques such as hydro-seedling shall be used on steep slopes and other difficult areas as a measure of soil erosion control and slope stabilization.
  • The effects of reclamation operations themselves over the surrounding environment should also be not ignored. The continuous monitoring should focus to account the effects of runoff on quality and quantity of surface waters; the effects of seepage on aquifer quality & recharge in ground water; effects on aquatic and adjacent terrestrial habitats & migration routes on wildlife habitats; changes in climatic conditions; flora & fauna;  changes in soil cover & land use for agriculture or forestry. For this, some sampling stations may probably have to be located outside the boundaries of the former mine site, so as to ensure that the surrounding conditions are satisfying the environmental criteria. This approach will provide the success of current management practice and helps in further for better planning.
  • After the reclamation project, monitoring team should ensure that the objectives of land reclamation are achieved.