TOO BIG TO HANDLE
set to be divided among six states— West Bengal, Bihar, Karnataka, Punjab, Uttar Pradesh and Tamil Nadu—and a public sector power generation company, Satluj Jal Vidyut Nigam. But it was awarded to West Bengal in 2019 because none of the others participated.
While the state government is promoting the coal mine as a developmental project that will generate more than 100,000 new jobs, it has sparked widespread protests due to impending displacements and environmental concerns. This has forced the state to revise its compensation package for the project twice since November 2021, when the first phase of the project was announced.
The Geological Survey of India, in a report published in May 2016, says it is “a unique type of coal deposit which has no parallel in Indian coalfields, because of the special structural features”.
The report says that while the 1.2 billion tonnes of coal reserves available in the block are “quite
Sources: West Bengal Power Development Corporation, Geological Survey of India and analysis by expers
tempting to mine”, it will not be easy with the existing technology of “both underground as well as opencast mining”. There are three challenges with the block that is spread across 1,360 hectares (ha) and split between seven coal seams, which are coal beds thick enough for mining.
First, the overburden, which is the space between the top soil and the coal reserve, is made of thin alluvial cover (1–20 metres or m) followed by very hard basaltic rocks of volcanic origin (90–245 m) and sedimentary rocks. Mines usually have an overburden of mixed soil and rocks that can easily be removed. “The only way to mine such a hard crust is through blasting or explosion. The machinery and expertise for this are not readily available in
India,” says Partha Bhattacharyya, former chairperson of CIL.
Second, the coal seams have a thickness of up to 79.89 m, which is substantially higher than what is ideally needed for mining (4-10 m) and handling such a large mine will be a logistical nightmare.
Third, the maximum depth of the block is 850 m. In India, open cast mining happens at a maximum depth of 300 m, while underground mining happens at about 600-700 m. “The project is technically feasible, but we will still need to rely on international expertise to deal with the thick basalt deposit and this will be expensive. Moreover, as you go deeper into the Earth's surface, the temperature rises. Additional cooling equipment will be required to deal with this, which would further increase the project cost. So, it is unlikely that the project will be economically viable,” says S Chandrasekhar, director (operations) at the Singareni Collieries Company, a mining company jointly owned by the Centre and the Telangana government.
He suggests that the block will
WHILE THE 1.2 BILLION TONNES OF COAL RESERVES AVAILABLE IN THE BLOCK ARE QUITE TEMPTING TO MINE, IT WILL NOT BE EASY WITH EXISTING TECHNOLOGY
require a mix of open-cast (in shallow regions) and underground mining. Currently, 6 per cent of India's mines are mixed, as per the Coal Directory of India, 2019-2020.
The state can also look at gasification, a relatively new mining method where coal is converted into natural gas using electrodes, eliminating the need to extract the coal from the mines. “You are interested in the energy of the coal, not the coal itself. The technology, though, has not yet been perfected,” says Bhattacharyya. In the National Coal Gasification Mission document released by the Union Ministry of Coal in September 2021, gasifying coal is one way of moving towards cleaner forms of energy. This is critical since India is a signatory to the Paris Agreement, 2016.
Bhattacharyya says even the quality of the coal is average. The coal quality in Deucha-Pachami block is G3-G14 and in DewanganjHarisingh, it is G6-G14, as per the West Bengal Power Development Corporation (WBPDC), the nodal agency for the project. “Anything
Source: West Bengal Power Development Corporation
block have several small stone mines, some legal but mostly illegal.