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(2) A general description of geologic conditions and mineral resources with appropriate <br />• maps, within the area where mining is to be conducted <br />Geologic/Hydrologic Conditions Within the Lease Tract <br />Geologic Overview <br />AMSO's Oil Shale Lease COC 69169 is located near Black Sulphur Creek, about six miles to the <br />west of Piceance Creek (Figure 2-1). The Tract is located near the crest of Black Sulphur Creek <br />Anticline. In most of the central part of the Piceance Creek Basin, the Uinta Formation is exposed, <br />overlying the Green River Formation, which outcrops in the deep incised valleys (e.g. Parachute <br />Creek) and in the basin margins (Figure 2-2). Wells 24-21-298-L3, Yellowstone Sulfur Creek Well <br />#1, and 29-82-103 (CH-1) provide detailed site specific geologic and hydrologic knowledge within <br />the RD&D Lease Tract. The geology is described in more detail in Appendix 2-1. <br />Unita Formation - This formation is formed mainly from clastic fluvial-deltaic sediments <br />prograding southward, intertonguing with the lacustrine Green River Formation. It includes mostly <br />sandstones and siltstones but also conglomerates, marlstones, and oil shale. The thickness of this <br />unit varies in localities and in the nominated area it is approximately 700-ft thick. <br />Green River Formation - This formation consists mostly of dolomitic marlstone and oil <br />shale. It also contains some siltstones and sandstones and sparse algal limestone beds, and it is <br />divided into several zones of rich oil shale separated by relatively leaner zones. The upper portion <br />• of the Formation is called the Parachute Creek Member and contains the Mahogany Zone, <br />the leached zone, and a nahcolite-rich zone. The Garden Gulch Member below the Parachute Creek <br />Member consists mostly of illite-rich shales. AMSO's proposed test retorts will be confined within <br />a mining interval that extends from the base of the nahcolitic oil shale at an approximate depth of <br />1830 feet below the surface to the base of the oil shale strata at an approximate depth of 2400 feet. <br />The mining interval is approximately the lower 500 feet of the Green River Formation. <br />Structure - The RD&D Lease Tract is located at the central part of the Piceance Creek Basin on <br />the southeastern part of Black Sulphur Creek Anticline near its crest. The structure's axis trends <br />NW-SE, with beds dipping gently to the southeast (1°-10°). A small normal fault with a <br />dolomitic sandstone dike was mapped trending northwest to southeast across the Test Pad.on the <br />RD&D lease. It is down thrown on the southwest and appears to be the northeastern bounding <br />fault of a graben. Other significant faults are located about 0.5 miles to the southwest. These <br />faults are subparallel to the anticline crest with fault exposures at Black Sulphur Creek showing <br />vertical stratigraphic separation of several feet. <br />• <br />10