Essay on Iron Ore of Mineral Resources

There are about 257 iron ore producing mines in the country. Madhya Pradesh and Chhattisgarh account for about 26 per cent followed by Goa with 22 per cent, Bihar and Jharkhand 19 per cent and Karnataka 18.8 per cent are amongst main iron-ore producing states.

Production of iron ore (including concentrates) during the year 1996-97 is estimated to be 69.1 MT. Out of the estimated dispatches of iron ore (63.8 MT), the share of dispatches of iron ore for internal consumption would be 40.4 MT and the balance is for export.

The internal consumption continues to record significant growth because a number of new capacities are coming up in the country.

According to a study of the world iron ore industry by the Brussels-based International Iron Steel Institute (IISI), a production of over 86 MT of iron ore is envisaged in 2005. The Geological Survey of India (GSI) survey indicates that given the current intensity of mining, Goa’s ore reserves are expected to peter out by 2020 A.D.

The state came into focus recently, when Goa’s valuable prehistoric sites were being badly affected by the pollution.

Though mining is the biggest contributor to the State’s economy, the degradation of the ecology was a matter of great concern because the best of efforts had failed to combat ore rejects from flowing into the rivers and affecting marine life and potable water. For every tone of ore extracted, two and a half tonnes of waste are created.

Many mining areas have been abandoned after extracting the ore, leaving behind large craters. Mining companies do take precautionary measures to control the flow of mining rejects, but such measures are not enough.

Agricultural land located close to the reject dumps has been adversely affected. In this context, some of the environmental control measures adopted by National Mineral Development Corporation in their Bailadila Iron Ore mines are worth mentioning.

It operates the largest mechanised iron ore mines in the country at Bailadila (C.G.) and Donnimalai (Karnataka). Apart from maintaining ambient air quality standards in the work zone of the iron ore projects, flow of the suspended solids from the screening plants of respective mines, or run-offs is being controlled by having tailing dams constituted of proper designs. Besides, a number of check dams have been constructed to arrest fines and reduce the velocity of flow even before reaching tailing dams.

At the upstream of the tailing dam, conditions are created for discrete and quiescent setting of solids. The quality of water discharged from the tailing dams, which act as the pollution control structure is observed to meet the standards prescribed in GSR 422 E.

In the absence of proper pollution control measures, the run-offs of Bailadila mines created heavy pollution which made streams and Shankhani River unfit for human consumption.

Tailing dams function as a pollution control facility where iron ore slime settles by physical means and clear water discharges downstream. Since the dam is new, recycling of solid waste is yet to start.

The waste dumps currently being piled up would be reclaimed after they reach their peak accommodating capacities. Systematic afforestation is underway. About 16 lakhs samplings have been planted so far and the survival rate is found to be encouraging (+90 per cent). Deposit number 5 of Bailadila is surrounded by lush greenery. Donnimalai iron ore project has been adjudged the best opencast mechanised mine in India (instituted by Federation of Indian Mining Industry (FIMI).

Major Cause

In the iron ore and limestone mines, a major cause of air pollution is transporting huge volume of iron ore, limestone etc. through open trucks/dumpers etc. It also leads to very heavy consumption of diesel, fuel oil etc. Burning of diesel/fuel oil etc. and transportation of minerals combining together aggravate dust, smoke and noise pollution in the mines. Attempts are being made the world over to develop possible alternative systems for surface transportation in mines in varying operating conditions.

Transportation systems, e.g., belt conveyer and slurry transport are therefore being increasingly used in USA, Canada etc.

The systems are reliable and provide higher availability. In Goa iron ore area, a belt conveyer system is operating successfully in a 3.5 MT pa mine for transportation of ROM from the quarry bottom involving a lift of around 300 metres. Slurry transport has been used in a large iron ore mine.

The use of these technologies in mines has become an alternative to trucks for ore and over burden transportation.

Limestone

India is endowed with abundant resources of limestone. The total reserve is of the order of 76,440 MT. Cement industry consumes 88.5 per cent of limestone followed by iron and steel sector 6 per cent, chemicals industry 3 per cent; and so on.

Limestone mining is carried out entirely by the open pit method in small, medium and large scale. Limestone and iron ore account for about 70 per cent of the total number of opencast mechanised and non-coal mines.

Technologies adopted in open-pit mines in India are generally comparable to those prevalent in other countries for the size of the deposits and the scale of operations.

Following are the environmental impact areas relating to typical limestone mining: (a) land degradation, (b) removal of top soil, (c) disposal of solid waste, (d) disposal of water regime and drainage pattern, (e) air quality, (f) noise pollution, (g) ground vibrations, and (h) socio-economic change etc.

The abatement measures being carried out in limestone mining for controlling damage to the environment are as follows:

The reclamation of mined land is done by landscaping or site preparation, soil amelioration and re-vegetation.

Even though there is mining degrade large gap between the area and that reclaimed so far, considerable emphasis is being laid on the need for back-filling of the worked out area with waste so that they could be reclaimed.

With respect to air pollution, suppression of dust by water sprays is one of the measures very commonly used in Indian mines be it drilling, blasting or that generated in road haul. Dust extractors are used in large diameter drilling in mechanised open cast mines.

Control of water pollution is done by provisioning of drains and check dams etc., which are some of the common abatement measures towards checking of water pollution. Control of noise pollution is achieved by: (1) reducing sound at source, (2) interrupting the path of noise, (3) reducing ground vibrations etc.

It has been observed that some limestone quarries after exploitation remain unattended and develop a crater and subsidence in the absence of rehabilitation measures. The disfigurement of the mining area is very common; almost barren mines area is also a common sight.