A blast at the Cordero Rojo coal mine in Wyoming’s Powder River Basin that accidentally set off additional explosives not intended for the blast was so powerful it registered on seismographs as far away as Europe. It could also lead to federal and state fines for Cloud Peak Energy Inc.
The May 1 blast was more than three times its intended size leading the Wyoming Department of Environmental Quality (DEQ) to issue two notices of violation for the blast, which could bring a fine of up to $5,000. Additional penalties could be levied if Cloud Peak does not submit by plans by next month on how to prevent such an accident from occurring again, the Casper Star Tribune reported.
The federal Mine Safety and Health Administration has also issued a citation, an administration spokesman said, but no penalty has yet been assessed.
The DEQ violations state that the mine intended to set off 12,180 kg (26,852 lbs) of explosives during a routine cast blast, a procedure designed to knock out large amounts of rock and soil above a coal seam.
However, the department said that upon detonation shortly after 11 a.m., explosives adjacent to the blast area were also accidentally set off, creating a blast in excess of the legal limit of 39,695 kg (85,308 lbs) of explosives.
The explosion was so large that some Gillette residents felt the ground shake from 25 km (16 miles) away, according to The Associated Press. Several European earthquake detection stations registered the vibrations from the blast, and seismographs at the University of Utah, 643 km (400 miles) away from the Cordero Rojo mine, initially recorded the shock as a magnitude 4.3 earthquake with an epicenter north of Green River, 50 percent closer than where the actual explosion took place.
The DEQ may slap Cloud Peak with a fine of up to $5,000 for the accident. DEQ spokesman Keith Guille said state officials are still deciding on whether to assess a fine and, if so, how much it should be.
The blaster in charge of the explosion, Marlyn King, and his assistant, Larry Raga, have also been suspended by the state for at least 60 days, according to the DEQ violations.
In addition, Cloud Peak must submit plans by June 11 to the state showing the steps it will take to prevent a similar incident in the future or face additional fines.
MSHA spokesman Jesse Lawler confirmed that a federal citation was issued for the blast, but he said that no penalty had yet been assessed.