In the fall of 2016, AAI drilled more than 27 holes into the Axial Coal Mine fire located on the Colowyo Coal Mine Lease near Craig, Colorado, for the Colorado Division of Reclamation, Mining and Safety (DRMS). The Axial/Streeter fire burned for more than 70 years prior to drilling activities. Nearly 3,000 feet of holes were drilled and nearly half the holes were cased.
AAI drilled into the fire using AAI’s track-mounted W/Five drill rig fitted with an HW casing advancer (4½ inch diameter) and down-the-hole (DTH) drilling capabilities. The track-mounted rig (Mooroka chassis) was used because of its ability to tram long distances to the drill site under its own power and work on the rough drill roads cut into the 45° to 65° sloping hillsides (similar to IHI). Holes were typically 75 to 140 feet long. Foam and water were used to cool the drill bits from the 350°F downhole temperatures. AAI’s crew wore special clothing and masks and maintained a gas tester on-site to protect against steam and toxic gases emitted from the fire. The holes were completed with 3.0-inch-diameter black steel pipe, grouted with bentonite grout, and capped. Holes are currently being used for mine-fire monitoring.