GENERAL44128

• Permit No: C1981013
• IBM Index Class Name: General Documents
• Doc Date: 6/30/2003
• Doc Name: Findings of the DMG Methane Assessment
• Permit Index Doc Type: Citizen Complaints
• Media Type: D
• Archive: No

underground methods. The presence o1 methane has long been established in the region, first idenlit)ed as a
coal mining hazard during the early days of mining. In 1910 a methane explos+on m the Primero mine, located
20 miles west of Trimdad. killed more than 100 men, More recently, within the last ten years, companies such
as Evergreen Resources. Williams, and Barrett Resources have establrshed extensive coal bed methane
production
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Specific setting
The area of investigation can be mostly described as the south ;; of Section 28, T33S R67W (Figure 1) The
contaminated area is within the north %, of the south %, of this section along wdh multiple man-made features
such as coal exploration boreholes, gas wells, water monitoring wells, underground coal mine workings. a
ventilation shaft. and gas gathering pipelines.
Geologic setting
The affected area lies parallel to the Purgatoire River valley. Dead or stressed vegetation occurs in an irrigated
pasture (Toupal pasture) and along the higher slopes north of Highway 12 in rangeland areas. The soil prol+le.
where present consists of clayey soils which support warm season grasses native to the areas, Older terrace
deposits of alluvial gravels and cobble size material underlie the soil proide and were clearly visible in the well
26-t0 mud pit prior to its reclamation. The underlying bedrock is the Raton formation, containing sdtstones.
sandstones, shale, and coal deposited in a deltaic environment during the Cretaceous period. The Maxwell
seam is the thickest seam m this area and contains the Golden Eagle mine workings slightly to the west of the
contaminated area. Above the Maxwell ke both the Red and the 81ue coal seams along with other mina rider
seams. (Figure 2) Total coal thickness in the overburden including the Maxwell seam is nearly 30 feet in this
area, making the coal bed methane potential of th+s zone very high. Faults in the subsurface were confirmed by