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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 |
