Peabody shares hit a record closing price low of $2.53 on Friday after plunging 9% that day whole Arch shares dived 12% to a new low of 39c.

Peabody shares closed down 5.5% lower to $2.39 on Monday while Arch shares treaded water.

Fears that Peabody and Arch could face higher environment-related insurance costs emerged last week.

“The Wyoming Department of Environmental Quality’s Land Quality Division is reviewing 2014 financial data from Peabody and Arch to see if they still qualify for a ‘self-bonding’ program that allows coal producers to cheaply insure their clean-up costs in case of bankruptcy, Kimber Wichmann, an economist at the department, said in a phone interview,”Bloomberg reported.

“Miners that fail to meet certain financial benchmarks must buy instruments that include corporate surety bonds and Treasury bills, or hold enough cash, to cover potential reclamation liabilities.”

Last week both coal companies also faced class action status-seeking lawsuits from former employees.

These were based on claims the coal companies had lost tens of millions from employee retirement plans by making risky investments in their own stock.