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Description of the Environment <br />The proposed Rimrock Mine permit area is situated on steep terrain dissected <br />by numerous drainages (EXHIBIT AA). The topography has been largely shaped by <br />the tributaries of the Purgatoire River, <br />Elevation on the mine property ranges from about 6,500 feet in the valley <br />where Engleville Gulch flows out of the permit area to 6,900 feet in the <br />eastern part of the property. The climate is semi-arid with annual <br />precipitation of 13" to 15". Prevailing winds are from the southeast at an <br />average speed of 8 miles per hour. <br />The permit area lies within the Engleville Gulch watershed, whose resident <br />stream is an ephemeral tributary of the Purgatoire River and has its <br />headwaters on the northern flank of Fisher's Peak to the southeast of the mine <br />permit area. The major topographic feature in the area is Fisher's Peak, <br />Geologically, the proposed mine site will be centrally located along the <br />eastern edge of the Raton Basin which is an asymmetrical structure with a <br />steep to overturned western limb and gentle eastern limb. Structural dip of <br />the sedimentary sequence in the permit area is approximately 2° to the west <br />southwest. There are three water bearing lithologic units identified in the <br />permit area. The Raton Formation, Vermejo Formation and the Trinidad <br />Sandstone from youngest to oldest. The Trinidad Sandstone is the only aquifer <br />of regional significance in the area. <br />One coal seam, the Engleville seam would be mined under the proposed plan. <br />The Engleville seam occurs near the stratigraphic center of the <br />Vermejo Formation, a 55 foot section characterized by alternating beds of <br />shale, siltstone, and sandstone. The coal seam averages about 10 feet in <br />thickness throughout the proposed mine site. <br />Soils on the side slopes of the mine site are shallow, being derived from <br />parent sandstone and shale layers which outcrop in the area. Soils in the <br />permit and adjacent areas are mixtures of two major units, the Ayon and <br />Capulin loam soil units. This type of soil is classified as class IV which is <br />a soil with severe limitations that restricts land use options and requires <br />careful management, <br />The primary vegetative community in the permit area is a warm season/cool <br />season grassland with scattered trees and shrubs. The adjacent areas have <br />similar vegetation with Pinon-Juniper predominating amidst grassland. The <br />area to be affected by the operation is characterized by a grassland community <br />with scattered trees. The dominant grasses on the site are blue grams <br />(Bouteloua gracilis) and western wheatgrass (Agropyron smithii). The <br />community a sT'o consists of lesser quantities oho Fer grasses, fortis and <br />cactus. Pinyon pine (Pious edulis) and gambel oak (Ouercus gambelii) occur in <br />small stands. <br />Pre-mining land use in the 38 acre surface disturbance area associated with <br />the Rimrock Mine as well as adjacent areas is primarily pasture and <br />rangeland. Mining began in the permit area in 1893 and has been intermittent <br />since that time. <br />- 4 - <br />