Crews have been working for the past three days to extinguish the fire in the underground coal mine owned by Alliance Resource Partners and operated by subsidiary MC Mining.

The Oklahoma-based company said the mine will be closed only until the fire can be extinguished, reported The Associated Press.

Employees discovered the fire late Saturday night. A state emergency response team helped fight the fire for seven hours but was unable to bring it under control.

The U.S. Mine Safety and Health Administration also has an emergency response team at the scene.

All firefighting personnel were withdrawn and the mine sealed on Sunday morning. Crews have been pumping nitrogen and water into the mine through surface boreholes while conditions underground are being monitored by fiber optic camera and gas-detection tools.

Excel No. 3 mine produces low-sulfur coal from the Pond Creek coal seam. The mine produced an average of 160,000 tons of coal per month in the past year.

Alliance Resource Partners operate mines in Illinois, Indiana, Kentucky and Maryland.