Abstract The origin of the subsurface fire burning since 1910 in the South Cañon Number 1 Coal Mine west of Glenwood Springs, Colorado, is unknown. Surface manifestations of the fire include gas vents (some encrusted with minerals), burnt vegetation, subsidence features, ash, sulfur, and red-oxidized shale. The minerals tschermigite, mascagnite, and gypsum formed in association with coal-fire gas exhaled from a gas vent on the western slope of South Canyon. Tschermigite and gypsum are reaction products of the gas with feldspar grains in the Williams Fork Formation. Gas collected from a vent and from soil above a burn zone in former underground workings on the eastern slope of South Canyon was found to contain numerous hydrocarbons, including n-alkanes, iso-alkanes, cyclo-alkanes, alkyl aromatics, alkenes, ketones, ethers, and a number of other volatile organic com-pounds, as well as sulfur compounds. Drill casings currently present in voids in the D coal seam on the western slope trail are useful for collecting gas samples, monitoring the temperature of subsur-face burning, and measuring the concentration of gases, such as carbon monoxide and carbon dioxide, in the field. The likely success of conventional fire-containment methodologies in South Canyon is questionable, although additional studies including drilling data may eventually suggest a useful control procedure. The 2002 “Coal Seam Fire” that burned over 12,000 acres and destroyed numer-ous buildings in and around Glenwood Springs exemplifies the potential danger an underground coal fire poses for igniting a surface fire. Coal-fire gas and the solid by-products of combustion contribute to the destruction of floral and faunal habitats and may be responsible for a variety of human diseases; hence, the study of coal gas and its by-products may prove useful in understanding environmental pollution created by coal-mine fires. Keywords: South Cañon Number 1 Coal Mine, coal-mine subsidence, coal fires, coal-fire gas, gas-vent minerals, coal-fire pollution.

Abstract The South Cañon Number 1 Coal Mine fire, in South Canyon west of Glenwood Springs, Colorado, is a subsurface fire of unknown origin, burning since 1910. Subsidence features, gas vents, ash, condensates, and red oxidized shales are surface manifestations of the fire. The likely success of conventional fire-containment methodologies in South Canyon is questionable, although drilling data may eventually suggest a useful control procedure. Drill casings in voids in the D coal seam on the western slope trail are useful for collecting gas samples, monitoring the temperature of subsurface burning, and measuring the concentration of gases such as carbon monoxide and carbon dioxide in the field. Coal fire gas and mineral condensates may contribute to the destruction of floral and faunal habitats and be responsible for a variety of human diseases; hence, the study of coal gas and its condensation products may prove useful in understanding environmental pollution created by coal mine fires. The 2002 Coal Seam Fire, which burned over 12,000 acres and destroyed numerous buildings in and around Glenwood Springs, exemplifies the potential danger an underground coal fire poses for igniting a surface fire.

Abstract Paleogene and Neogene faults and fractures on the eastern edge of the Colorado Plateau are present in Mesaverde Group coal and sandstone beds. Recent observations of coal cleat orientation in relation to faults in coal mines have significant impacts for mine planning in the area. Faults, coal cleats, and natural fractures are interpreted to show a structural evolution of the Mesaverde Group through time. This field trip will include a visit to two active underground coal mines, the Bowie Resources’ Bowie No. 2 Mine, and Mountain Coal’s West Elk Mine. Mine geologists will discuss structural styles including fault orientations and timing, cleat development, and rotation. Geologic encounters ranging from fault flooding, subsidence, mine fires, methane gas problems, and land use restrictions will also be discussed. Coal cleat development and open-mode fractures in adjacent sandstones will be observed on outcrops and compared to underground measurements in coal mines in the Somerset Coal Field, Colorado’s most productive. Coal cleat orientations along a reverse fault in one mine will show rotation in relation to possible Neogene age displacement. This two-day trip begins at the Convention Center in downtown Denver, Colorado. Participants will be transported in vans westbound on Interstate 70 to Glenwood Springs, then south on State Highway 82 to Carbondale, then southwest on State Highway 133 to Somerset, with a lunch stop in Redstone to observe 100-year-old coking coal beehive-shaped ovens. The first afternoon will include a stop at Paonia Reservoir Dam for introductory remarks on the regional fracture development of the Somerset Coal Field and a mine tour at the West Elk Mine, which has encountered warm water flooding in large-scale faults associated with the West Elk Mountain uplift. We will head to Paonia for dinner and overnight. The second day will include a stop at the reclaimed Bowie No. 1 portal to observe fracture patterns on the west side of the coal field and an underground tour of the Bowie No. 2 Mine and possibly the new Bowie No. 3 Mine, where the mine geologist will discuss observations of coal cleat orientation changes in relation to faulting. Recent coalbed methane exploration in the southern Piceance Basin will also be addressed. Then we will drive a four-hour route back to Denver with a quick stop at the Muddy Creek Landslide, a 2.5 mi2 (6.5 km2) active earth flow complex.