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Larenciro Cam~on Mint - Gcolofly Terhnicaf Rcport • Rock coring activities were conducted by John T. Boyd in 1980. This exploration involved shallow coring at the surface and shallow subsurface boreholes to analyze for coal quality. No core data was available for this exploratory ac[iviry. In 1984 Rocky Mountain Energy conducted IS borings (designated as CR in Map 2.04.6-I) at the site. These were confirmatory borings re- drilled near previous Boyd boreholes. In 1988 Anaconda drilled 43 boreholes and corings (designated as LT in Map 2.04.6-1). No other exploratory activities occurred at the site until the early 1996 activities commenced. These boreholes in addition to the boreholes conducted in 1996 were used to correlate and interpret site stratigraphy and structure. A regional geologic map is included as Figtu•e 2.04.6-1. A geologic map of the permit area is included as Map 2.04.6-2. Appendix G-2 includes geologic cross sections of the permit area. The site area is underlain by rocks of the Upper Cretaceous and Paleocene Raton Formation and the Paleocene Poison Canyon Forration. The Raton Formation is a coal bearing unit within the Raton Basin. The Raton Formation consists of a sequence of sandstones, shale, siltstone and coal units deposited in a delta-plain and fluvial environment. Sandstone units are channel in origin. The upper portion of the Raton Formation is a combination of fluvial and colluvial sedimentation caused by marine regression during the Laramide uplifr during sediment deposition within the basin. Continued marine regression resulted in grading into the coarser sediments of the Poison Canyon Fortation. • The Poison Canyon Formation consist of distal and proximal fan deposits. The Poison Canyon distal facies consists of massive buff to red azkosic sandstone and conglomerates with thin yellow shale beds. The larger grain size and unweathered feldspaz grains distinguishes the distal and proximal Poison Canyon from the Raton Formation. The igneous geology encountered in the permit area consists of intrusive sills associated with the Spanish Peaks. Outcrops of basalt occur in areas located in Little Jeff Canyon, Puertecito Canyon and Cow Canyon. The basalt is weathered in these areas and predorrtinantly consists of fine grained, dazk grey rocks. The sills aze the cause of metamorphism of coal to natural coke in the Raton Basin and possibly the permit area. The stratigraphy of the units included within the permit azea can be divided into six hydrogeologic units. A lithologic column of the units in the permit area is included as Figure Gl. The six hydrogeologic units identified are: • alluvium, which includes the unconsolidated valley fill material in drainages; • overburden, defined as the unit overlying the Ciruela coal; • Ciruela coal; • Gcology~476/December f4, 1996 5