Elevated carbon monoxide levels that led to the idling of Foresight Energy's Deer Run longwall mine near Hillsboro, Illinois, almost three years ago recently reappeared, apparently caused by another hotspot in the same underground area, an official with the Illinois Office of Mines and Minerals said Tuesday.
Art Rice said in an interview that the hotspot was detected by the St. Louis-based company during the past couple of weeks.
"[Through the] existing boreholes they had they were able to find out that they've got another hotspot over that fall area," he said, referring to a previous roof fall near the longwall site.
Foresight, now majority owned by Ohio-based Murray Energy, said in a filing with the US Securities and Exchange Commission late last week that it submitted a Deer Run re-entry plan on December 20 to the US Mine Safety and Health Administration.
"The re-entry submission contains a plan for the permanent sealing of the current longwall district of the Deer Run mine immediately upon MSHA's approval," the company said.
It added: "At this time, the partnership is uncertain as to when production will resume at its Deer Run mine."
In a Tuesday email, Murray/Foresight spokesman Gary Broadbent declined to elaborate on Foresight's filing.
Deer Run, also known as Hillsboro, has largely been idle since March 26, 2015, when MSHA ordered the mine shut after elevated carbon monoxide levels were found. The mine had come off its best year in 2014 when it produced 5.5 million st of coal.
According to Rice, Deer Run is located in a geological region of the state that is prone to spontaneous combustions in underground coal mines.
Peabody Energy's former No. 10 mine and Freeman United Coal's former Crown II mine also were plagued by occasional spontaneous combustions and elevated carbon monoxide readings, according to Rice.
