Dont know about the pits, but a typical opencast site moving 200,000m3 muck a week running 24hours might employ about 200 people directly. There is a lot of indirect jobs reliant to some degree on the sector though.
Suppliers, consultants, haulage firms, on site contractors, customers,Councils, SEPA/EPA, and other government bodies have employees dependant on coal production to some degree
This does not take into account other businesses and services eg shops, mechanics, barbers, schools and libraries, all of which suffer when an area loses an industry that may directly employ 2 or 3 thousand people. The knock on effects can be quite dramatic. Personal experience of Ayreshire for example, towns already struggling have had the final nail drilled into the coffin this year.
Coal could have benefited from some of the tax breaks and assistance from government at both UK and Scottish level provided to other sectors.
I am not complaining about wind farms though as they are now partly responsible for my current employment.