Koch told E&E Publishing that “a lot of the profit had gone out of the coal business”.

His sentiments are on par with current industry opinions, with low natural gas prices enticing buyers away from coal.

Koch said the main reason for the drop in coal prices was the abundance of natural gas that had been discovered by shale drilling.

He went on to accuse President Barack Obama of “driving more nails in the coffin” through the president’s pledge to cut carbon emissions.

However, Koch insisted that the coal industry was far from dead and cited the US Energy Information Administration’s forecast that coal would account for 32% of electricity consumption by 2040.

Oxbow has coal and natural gas interests but is primarily a petroleum coke distributor.

The company recently closed its Elk Creek coal mine after a gas explosion in January.

“Fortunately, no one got hurt but if we went back in it could have killed people, so we're saying, 'All right, we're going to close it’," Koch told E&E.

Elk Creek was one of the largest underground coal mines in the US, producing more than 6 million tonnes of coal each year at its peak.