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Vol. 10 No. 1 - January 2004

Biological Reclamation of Degraded Mined Land

A Sustainability Indicator

By: Siddarth Singh

In the mining industry in India, a trend has emerged for the adoption of advance technologies intended for maximum extraction of mineral resources, to fulfill the developmental needs. As a result, they have achieved very high production rate and huge profit margin. The most fitting example is the shift in the technology of coal production from relatively safer underground to highly damaging open cast (surface) mining. Unfortunately, most of the technological enhancement has taken place in production technologies without any concern for ecology and environment. This resulted in severe ecological problems such as loss of our precious prime agriculture land, forest cover, water regime, air quality and biodiversity. With the rising global environmental awareness, the concept of sustainability started gaining popularity.

Sustainable development of the Indian mineral and mining industry with ongoing economic reforms is facing enormous challenges and opportunities. Opportunities for investment and hence technological enhancement have opened up in almost all areas including exploration, mining, mineral beneficiation, mining equipment, mineral utilization and environmental protection. Sustainable development by far remains the most important challenge faced by human society in the 21st century. Development with minimum disturbances to environment without compromising economic growth and quality of life should be our major concern.

MINING AND ECONOMY

Mining industry in India, second largest to agriculture, is one of the largest provider of employment and accounted for about 2.3% of the total GDP i.e. Rs. 45,230 crores in the year 2000-2001. We produce 64 minerals and the distribution value of mineral production in the year 2000-2001 shows that fuel accounts for about 83% (solid fuels 37% and liquid/gaseous 46%), metallic minerals about 7%, non-metallic minerals about 3% and remaining by minor minerals. Coal remains the primary source of energy, accounting for about 80% of total energy generation in the country. About 310 million tonnes of coal was produced in the year 2000-2001 and it ranked third in the global market. In the coal sector, all that is achieved must be credited to the nationalization of coal companies in 1971-72. Post-nationalization era has witnessed a sea change in mining technology as well as scale of operation. Relatively clean, underground mines occupied more than 70% share of coal extraction before nationalization. Gradually, more and more open cast mines were opened to balance the demand/ supply ratio and at present, they dominate with 80% share. India is a major exporter and holds globally a very strong position in the production of chromite, kyanite, illimanite, iron ore, bauxite and manganese ore.

MINING AND LAND DEGRADATION

Land degradation is considered as an unavoidable by-product of mining and can be widely defined as a human induced or natural process that negatively affects the land to function effectively. UNEP (1992) describes it in a simplified definition as “the temporary or permanent lowering of the productive capacity of land”.

Nature has endowed us with a variety of mineral resources. The matter becomes sensitive as most of the mine sites traversing from the height of Himalayas to the sea shore of eastern and western ghats and peninsular India fall in the ecologically fragile and biodiversity rich area. Land degradation due to mining has reached alarming proportions mainly due to over exploitation and mismanagement of natural resources. One of the consequences of ever increasing human population, supported by accelerated land degradation is lowering of the man-land ratio. Our per capita land availability has been reduced to 0.328 ha.

Mining and industrial waste has been estimated to degrade 0.04% of total geographical area of the country. Mining complexes as estimated recently occupy around 36-lakh hectare of land, which is 0.11% of total land area of the country. Ministry of Agriculture, Government of India has estimated that the proportion of land degraded due to mining and industrial waste was about 2.53 lakh ha in 1994. Although the figure is not very significant, its enormity can be understood by the fact that the total degraded land is 55% of the geographical area of the country.

MINING AND SUSTAINABLE DEVELOPMENT

With the publication of The World Commission on Environment and Development’s report One Common Future in 1987 also known as Brundtland Report the concept of sustainable development came into the prominence. There was a big question mark on extracting industries (Mineral, Petroleum and coal) for sustainable development since long. Almost all the mining techniques from mineral explorations to production and transport are causing environmental damage in several ways. The list includes deforestation, loss of top soil, accelerated soil erosion, soil contamination, qualitative and quantitative depletion of surface and ground water resources, migration of wild life and avian fauna, and addition of air pollutants and dust in the atmosphere. Several of these constraints are exceptionally difficult to avoid in surface mining. Thus, it sounds unconvincing to achieve sustainability in mining processes. A lot of debate and very little agreement has taken place for the sustainable status of extracting industries.

Sustainable development is widely defined as “development that meets the needs of the current generation without compromising the ability of future generation to meet their own needs”. It has been further elaborated in 1991 by Ecologically Sustainable Development Working Group on Mining as “ensuring that the mineral raw material’s need of society are met, without compromising the ability either of future societies to meet their needs, or of natural environment to sustain indefinitely the quality of environmental services such as climate systems, biological diversity and ecological integrity”. Such sustainable development conserves the resources like land, water and biodiversity. Sustainable systems are less risky, environmentally non-degrading, technically apt, economically feasible and socially acceptable.

The World Summit on Sustainable Development at Johannesburg 2002 has defined the role of stakeholders in sustainable development and rights and responsibilities in development processes. Thus, one can infer that mining under appropriate environmental guidelines, can only be sustainable through participatory process of assessment and commitment involving governments, industry, non governmental organizations, community and individual stakeholders in the decision making process, directed towards optimizing economic development while minimizing environmental degradation.

BILOGICAL RECLAMATION AS A SUSTAINABILITY INDICATOR

Many of the social issues responsible for the outcry can be subsided by providing the source of livelihood to the affected inhabitants. Biological reclamation of the degraded land with predetermined end use has the potential to fulfill it. In the majority of cases, reclamation of abandoned mineral workings requires the establishment and maintenance of vegetation on disturbed land. No other medium can achieve rapid visual integration, surface stabilization, or reduction in air and water pollution, nor offer a wide variety of land-use possibilities, which can be achieved at acceptable cost. Based on several ecosystem restoration studies, A. D. Bradshaw, the pioneer restoration ecologist, concluded that vegetation is the most appropriate and cost effective long- term remedy to encounter the majority of underlying problems of derelict-mined land.

Revegetation of mined out areas is often difficult due to its chemical and physical traits. Absence of topsoil is the most common feature of the mine spoils or dumps. If present, it is very poor in nitrogen, which is essential for plant growth. This is due to the absence of soil organic matter provided by decay of dead plant material. Moreover, dearth of soil micro flora restricts the decay of plant material. In addition, the stony nature of mine wastes aggravates the situation further for vegetation establishment by developing low infiltration rates and water retention. Since the progress of natural vegetation process is very slow on mine spoils, selective plantation of suitable native species is desired in most cases.

In common practice, mining engineers, always unguided by any ecological principle prefer to establish some greenery on wasteland. However, the development of a permanent vegetation cover should aim to establish a plant community that will maintain itself indefinitely without attention or artificial aid, and support native fauna. To extract better results, some ecological variables must be considered while selecting species for plantation. These are; their capacity to stabilize soil, increases soil organic matter and available soil nutrients, and facilitate under storey development. In the initial stages of revegetation quick growing grasses with short life cycle, legumes and forage crops are recommended. It will improve the nutrient and organic matter content in soil. Plantation of mixed species of economic importance should be done after 2-3 years of growing grasses.

The biological reclamation in its lowest magnitude intends to put the degraded land to some use to the stakeholders. On the other hand, it may be designed to accomplish the ecologically challenging task of reestablishing the previously existing ecosystem, going species by species. Now the question arises about the criteria of sustainability indicator and whether biological reclamation fulfills it?

It is impossible to replenish the minerals once mined out, however; we can reclaim the derelict land by establishing self-sustaining vegetation cover with pre- determined end use. A successful biological reclamation restores the natural capital of flora and fauna and productivity of land, which had been previously converted into fabricated capital through mining. This feed back mechanism very strongly advocates the suitability of biological reclamation as an indicator of sustainability and sustainable development of mining industry.

Dr. Siddharth Singh is a Scientist at the Central Mining Research Institute, Dhanbad- 826 001, Jharkhand, India


This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.


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