Officials at Japan’s Sumitomo Corp. have announced they and Brazilian joint venture partner Vale S.A. will close their Isaac Plains coal mine in Queensland, Australia, by Q1 2015 amid slackening coal prices.

The project, which lies in the Bowen Basin, produces both thermal and metallurgical coal and employs 300. The asset has proven reserves exceeding 44 million tons, said company representatives; in Q4 2012, 108 workers were also fired after both companies reduced production.

Last week, top miner BHP Billiton plc and Mitsubishi last week similarly announced 700 job cuts at their coal mines elsewhere in the Bowen Basin, also citing a difficult market.