Colorado Revised Statutes Title 34. Mineral Resources § 34-61-104. Oil or gas entering coal seams

When boreholes for gas or oil are drilled in the coal measures and pass through workable seams, if gas or oil is encountered in such borehole, the coal seams or worked out coal seams shall be sufficiently protected by casing so that the gas or oil shall not come in contact with the coal seams or enter the excavations of worked out seams. When no oil or gas is located and the borehole has been abandoned, a solid cement plug shall be placed extending from fifty feet below each coal seam to fifty feet above the top of each coal seam and at the surface to a depth of twenty feet.