Patriot announced Wednesday it had based its decision on a cost per ton basis, idling mature higher-cost facilities, but will continue developing lower-cost operations.
Remington’s two underground mines and one surface mine in southern West Virginia produced 1 million tons of thermal coal last year.
Patriot said the low mining recovery resulted in a higher cost structure and in today's softer market conditions the complex was not economically feasible.
The Black Oak mine, also in West Virginia, is a follow-on operation to replace metallurgical production from the depleting Harris mine.
Patriot blamed weak coking coal demand for its decision to suspend the operation. The company had expected to produce 900,000t from the mine this year.
In conjunction with the idling of the Black Oak mine, the company will also reduce manpower and operating time at its Rocklick preparation plant.
Patriot gave notice on Wednesday to about 400 workers.
Despite closing two mines this week, and the Jupiter complex earlier this month, Patriot is continuing to develop projects already underway, including Blue Creek and Hill Fork.
The Blue Creek complex, including two underground mines in Kanawha County, West Virginia, is targeting output of 1.8Mtpa of thermal coal. Mining will start as early as April this year.
Patriot says the complex includes a reserve base of 80Mt, has favourable seam thickness and clean tons per foot of advance, and is anticipated to be a low-cost source.
The Hill Fork surface mine in Boone County, West Virginia, will target output of 800,000t of thermal coal annually, with output commencing as early as next month.
Patriot said as a surface mine can feed into existing infrastructure, Hill Fork was designed to produce coal with a very competitive cost structure.