Cloud Peak Energy Inc. is facing state and federal violations after blasters at its Cordero Rojo coal mine in the Powder River Basin set off a massive explosion earlier this month that was more than three times its intended size.
The May 1 cast blast at the mine, located 18 miles south of Gillette, shook the ground for miles and activated seismographs as far away as Europe.
The Wyoming Department of Environmental Quality has issued 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 doesn’t submit by plans by next month on how to prevent such an accident from occurring again.
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 26,852 pounds 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 85,308 pounds of explosives.
The explosion was so large that some Gillette residents felt the ground shake from 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, 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.
Cloud Peak spokeswoman Molly Nichelson said Monday that she didn’t know exactly how large the blast was, nor what type of explosive was used. However, she said the explosion caused no injuries and only minor property damage.
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 last week, but he said that no penalty had yet been assessed. Lawler didn’t have further details about the citation on Monday.
Nichelson said that the company is cooperating fully in the matter and will continue to work with authorities to enhance their safety systems.