Plant retirements brought by new government regulation on air quality have made the situation even worse.

Average on-site employment at Kentucky coal mines dropped to 10,356 in the first quarter, down 10.6% from the fourth quarter of 2014 as production fell 8.4% to 16.68 million tonnes, according to a report released April 30 by the Kentucky Energy and Environment Cabinet.

First-quarter employment on annualised basis was at its lowest point since the statistics were first tracked in 1927 while annualised production was at its weakest point since 1961, based on separate figures the cabinet provided to SNL Energy.

Average first-quarter coal jobs in the eastern half of the state fell 8.7% from the fourth quarter of 2014 to 6,530 on an 11.5% drop in production to 7.5Mt.

It is the first time western Kentucky coal jobs have averaged below 4000 since the first quarter of 2010 and the lowest level since the fourth quarter of 2009, when they averaged 3651.