A US Mine Safety and Health Administration spokesperson told ILN Thursday that agency inspectors have been at Bull Mountain’s Signal Peak operation near Roundup every day since the high levels were first detected the afternoon of December 1.

“A nitrogen generator has been injecting nitrogen into the area where the CO was discovered,” Amy Louviere said.

“A second drill hole is being cased now right and is intended to provide means to drop a camera down and look for evidence of heating; it is also a likely injection point for additional nitrogen.”

As of Thursday, MSHA and the operator were making preparations for the arrival of a tanker load of liquid nitrogen.

The agency also confirmed that its Tech Support ventilation engineers are due to arrive at the mine Friday to comprehensively examine ventilation circuits.

Signal Peak spokesperson Mike Dawson told the AP Thursday that work above ground at the mine continues, and no layoffs of the mine’s 300 workers are anticipated. He said there is no timetable for the resumption of mining.

Signal Peak and its operating subsidiary, Bull Mountain, are owned by Boich and First Energy as well as the Gunvor Group.