Hi, Raahil,
I'd some across these links last year of some students who were mapping mining in OpenStreetmap. I didn't find out more about them, had just saved the links for future exploration. Check it out:
Harnessing transparency initiatives to improve India's environmental clearance process for the mineral mining sector
in the zipped dataset is a CSV with lat-longs of mines (maybe possible locations, maybe confirmed - idk)
And a pdf report: "Detection of Surface Mining Activity" by some IITD profs:
Then, had found these links:
This stuff might not be directly related to coal mines, but might help you find what you're looking for or connect with other folks who can help, so sharing. All the best.