ARP will pay an undisclosed amount for the Onton No. 9 mining complex in Webster County, Kentucky and about 40 million tons of coal reserves in the West Kentucky No. 9 coal seam.

The company said Onton No. 9 is a room-and-pillar continuous mining operation that employs about 315 workers and produces about 2.1Mt of coal per year.

It said all of the mine’s 2012 production is committed and Green River is building an air shaft to allow a fourth continuous miner to be added to the existing three if demand warrants it.

ARP president and chief executive officer Joseph W Craft III said the acquisition would enhance the company’s presence in the growing Illinois Basin coal market and would give it increased flexibility in servicing its existing customer base.

According to ARP’s website, its other Illinois Basin operations – Dotiki, Gibson County, Hopkins County, Pattiki, Warrior and River View – produced a combined 24Mt in 2010, about 80% of the company’s total production.

Another Illinois Basin mine, Gibson South, is scheduled to start production of 3-3.5Mtpa in 2014.

Before the Green River purchase, ARP was predicting full-year 2012 production of 34-35Mt, helped by the start-up of its Tunnel Ridge longwall mine in West Virginia.