The U.S. Office of Surface Mining Reclamation and Enforcement is seeking additional public input on the expansion of a GCC Energy LLC mine in Colorado.

GCC applied to modify its existing lease on the Colorado mine several years ago when it sought to add an extra 952 acres. GCC Energy is a subsidiary of Mexico-based Grupo Cementos de Chihuahua.

The coal from the mine is used primarily to supply cement plants and a railroad, according to the OSMRE letter. GCC was granted an emergency exemption in July 2016 from the moratorium on new coal leases currently in place.

According to a letter from the OSMRE dated earlier this month, the land is split between the federal government, which manages the underground minerals, and the Ute Mountain Ute Tribe, which owns the surface lands.

Data from the U.S. Mine Safety and Health Administration indicates that the King II mine produced 632,605 tons of coal in 2016, down from the 814,544 tons it produced in 2015.

GCC Energy did not respond to a request for comment. A comment period on the expansion plans of the King II mine ends Feb. 5.