A unique initiative by Coal & Lignite PSUs under Ministry of Coal
Overburden to sand : Waste to wealth

Rajiv R Mishra *

Even as the mandate is to produce & despatch coal/lignite to its consumers, Coal & Lignite PSUs, under the guidance of Ministry of Coal, has taken an out of box initiative to produce sand from overburden at a much cheaper price. This initiative is not only helping in minimising environmental pollution due to sand siltation from overburden, but also providing an option for getting cheaper sand for construction purpose.

Production of sand has already started in Coal PSUs & a roadmap of next five years has been drawn to maximise the output of sand from Coal India Ltd. (CIL), Neyveli Lignite Corporation (NLCIL) and Singareni Collieries Company Ltd.

The extraction of coal comes with a significant by-product known as Over- burden. During opencast mining of coal, the strata lying above coal seam is known as overburden comprising of clay, alluvial sand & sandstone with rich silica content. The overburden is removed to expose & extract coal from beneath. Later, on completion of coal extraction, the overburden is used for back filling to reclaim the land in its original shape.

While extracting overburden from top, swell factor of the volume accounts for 20-25%. This overburden has traditionally been considered waste or burden and often discarded without recognizing its potential value. However, with the growing focus on sustainable practices and the circular economy, there has been a shift towards exploring alternative uses for overburden, transforming it from Waste to Wealth.

First Initiative

The first commercial initiative of such conversion was taken by Western Coalfields Ltd. (WCL), a Subsidiary of CIL, in its mine during 2016-17. A Pilot Project was launched in Bhanegaon Mine in Nagpur District of Maharashtra, where sand was extracted through machines erected departmentally. The capacity of this machine was 300 cubic metres per day. The sand so extracted was put under thorough test & was ultimately found to be better than the riverbed sand.

The price was around Rs 160 per cubic meter which was almost 10% of the then existing market price. This sand was offered to Nagpur Improvement Trust for constructing low-cost houses under PMAY. Further two more departmental equipment were commissioned.

On success of the Pilot Projects, WCL launched commercial production of sand by commissioning the largest sand production plant of the country in Gondegaon Mine, near Nagpur. This unit produces 2500 cubic metre of sand per day at about half the market price.

Partnerships with Government Units and Local Sales : Major chunk of sand produced from the largest sand producing plant at Nagpur is being given to Govt. units such as NHAI, MOIL, Maha Genco & other smaller units at one third of market price. Rest of the sand is being sold through open auction in the market which is helping locals to get sand at a much cheaper price.

Waste to Wealth: A Paradigm Shift : Overburden, once considered waste material, is now being recognized as a valuable resource. The sand processing units are also generating tremendous employment opportunity as the local populace in large number are getting engaged in not only production unit but also in the loading & despatch of sand to the consumers through trucks.

Expansion Plans and Impacts on Society : As a part of this positive outlook and the exploration of alternative uses for overburden, CIL has commissioned several overburden processing plants and sand production plants across its subsidiaries in eastern & central part of the country.

As part of this sustainable effort, there are nine Overburden to sand production/processing plants already under production in Coal PSUs, out of which four are in SCCL, three in WCL & one each in NCL & ECL. The total annual capacity of these sand produc- tion/processing plants is about 5.5 million cubic meter per annum.

Furthermore, four Overburden to sand plants are in various stages of tendering in different subsidiaries of CIL. Lignite producing company NLCIL is also coming up with two sand producing plants. All these new upcoming plants will have a total annual sand production capacity of about 1.5 million cubic metres per annum.

Way Forward : Through pioneering initiatives, Coal/Lignite PSUs are spearheading a transfor-mative approach to sand production and consumption, contributing to envi- ronmental sustainability and societal well-being. Ministry of Coal has been encouraging Coal/Lignite PSUs to start this out of box initiative to produce more M-sand from overburden at an affordable price.

With advancement of technology & huge volume of production of sand in next few years in different locations of our country, the price per cubic metre will decrease substantially which will help the common man to have affordable sand for construction purpose. This will also help in minimising the use of riverbed sand which in turn will be beneficial for environment.