While they agree that the primary reason for grade variation is the inherent heterogeneous nature of Indian coal having difference in calorific value of coal extracted within the same seam at different points, they allege, many a official in charge of stock at the CIL pit heads are forced to mix basalt with coal for the purpose of over reporting.

Even as quality issues have started cropping up with Coal India (CIL) enhancing supplies to the power sector, CIL says it has been able to achieve improved grade conformity even after the monsoons when there are increased chances of grade slippages.

A CIL executive told Fe that till August this year the grade conformity was 63%, up from 60% during the same month last year. But a section of power engineers are of the view that power plants’ present average 7 days stock position with around 13.4 million tonne have a lot of basalt and soil mixed in it. Such basalt mixed coal are preventing boilers’ optimum function and damaging those to some extend as well.

While they agree that the primary reason for grade variation is the inherent heterogeneous nature of Indian coal having difference in calorific value of coal extracted within the same seam at different points, they allege, many a official in charge of stock at the CIL pit heads are forced to mix basalt with coal for the purpose of over reporting.

Basalts are mainly found in the mines of the Rajmahal area under the Eastern Coalfields (ECL) and those are removed as overburdens. But plants mainly linked with the ECL are facing the problem, though most of the mines in other CIL subsidiaries are basalt free.

CIL said mine gradation is determined by Coal Controller’s Office annually, a statutory body under the government of India, and CIL has nothing to do with mine gradation. Nevertheless during last fiscal, coal quality reflected a positive jump as the grade conformity improved to 63% from 59% over the preceding year as per the third-party sample analysis. CIL, until August this year, has been able to stick to its last year’s grade conformity.

The PSU miner has engaged two more globally reputed third party sampling and testing agencies including COTECNA Inspection India and SGS India to ensure lesser grade slippage. This engagement has been done in addition to the existing agencies namely CSIR-CIMFR and Quality Council of India, a CIL executive said.

CIL ascertained the quality of supplies during the last fiscal, sampling and analysing 487 MT compared to 448 MTs in FY20. “Sampling to production was higher in FY21 and is likely to be higher at the end of the current fiscal, though total production this fiscal is expected to surpass the FY20 level at 602 MTs,” the CIL executive said.

Production with surface miners in open cast (OC) mines, entail blast free selective mining leading to better quality coal output. During the first half of the current fiscal, around 54% of the entire OC production was through surface miners at 127.6 MT, a growth of 11.6% compared to 114.3 MT during the same period last fiscal. Surface miners produced 279.92 MT in FY21, 49% of the company’s total OC production at 569.77 MT. Production growth through surface miners was 4% compared to surface miner production in FY20.

Although CIL agreed that there might be some grade slippage for heterogeneous nature of Indian coal, grade slippage came down to 23% during the last two months of FY21 from 43% during the same period the preceding fiscal. The company got a net quality bonus of `660 crore last fiscal, expected to be higher at the end of the current fiscal.