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_18_ Probable Hydrologic Consequences of the Twin Pines No. 2 .Mine Twin Pines Coal Company, Inc. provided information on the probable hydrologic consequences of the mine on pages 94 and 95 of the permit application. This information was supplemented by the report written by J.F. Sato and Associates provided by the Small Operators Assistance Program (S.O.A.P). The probable hydrologic consequences of the proposed T•.vin Pines No. 2 Mine are negligible on the scale of the general area. However, the Division has identified several potential impacts to the prevailing hydrologic balance in the permit and adjacent areas. Possibly impacts to the prevailing hydrologic balance within the permit and adjacent area are discussed according to the following format: first, the hydrologic regime; secondly, the uses made of the water resource; thirdly, the probable hydrologic consequences to the water resource; and last, the resolution of the identified problem. A. Ground Water Ground water within the permit and adjacent area is similar to that in the general area in that there are three ground water systems: the Trinidad Sandstone, alluvial aquifers and aquifers within the Vermejo Formation. The Trinidad Sandstone is approximately 600 feet below the Brookside seam which is proposed for mining at the Twin Pines No. 2 Mine. No use is made of this aquifer within the permit and adjacent area. The two strata are separated by many impermeable zones and are not hydrologically connected by faults or fractures. Therefore, the probable impact to the Trinidad Sandstone aquifer is negligible. An alluvial aquifer is found along the flood plain of Oak Creek, one mile north of the permit area. Unconsolidated alluvial materials, consisting of sand, gravel and clay are found along Oak Creek. This alluvium is estimated to be a maximum of 30 feet thick overlying the consolidated bedrock. The water level in the alluvium is in direct contact with the surface water levels and flow of Oak Creek. The alluvium of Oak Creek serves as the source of water for the town of Rockvale's water system, which consists of five hand-dug wells in the alluvium of Oak Creek in Sections 34 and 35, T19S, R70W (see Figure 2). A pipeline system connects these wells and water flows by gravity to the reservoir system west of town. During the permitting process, possible impacts to the Oak Creek alluvial aquifer and the source of water for the Rockvale water system were analyzed. The Division determined that surf ace and ground water flows from the permit area do not contribute to the source of water for the Rockvale system because; 1) the wells are upstream of the point where surf ace water from the permit area flows into Oak Creek, and 2) the alluvial wells are updip from the mine since the coal seam to be mined dips to the southeast away from the creek. The only potential impact is where the mine access road crosses over the pipeline which supplies water to Rockvale. Twin Pines Coal Company, Inc., has designed the access road to protect the line from damage by placement of more than three feet of cover over the line.