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to 120 feet of overburden strata in the permit area. The entire overburden section is in the <br />Fruitland Formation. <br />The Kirtland Shale conformably overlies the Fruitland Formation. This shale is divided into three <br />main members: the upper and lower shales and the middle Farmington Sandstone. The <br />Farmington Sandstone member forms a permanent ridge separating Carbon Junction Canyon and <br />REA Canyon. The lower shale member consists of gray to gray -green shale and sandy shales. <br />The upper shale member consists of interbedded shales and sandstones. <br />The Quaternary terrace deposits consist of Pleistocene -aged gravels related to glaciation in the <br />area. Three gravel terrace layers have been mapped in the area and represent previous flood <br />plains of the Animas River. These deposits vary between 1 and 100 feet thick and consist of <br />boulders and cobbles in a silt clay matrix. <br />Quaternary alluvial deposits are primarily located along the Animas River. Thin (less than three <br />feet thick) isolated alluvial bodies are located in Carbon Junction Canyon. <br />The Quaternary terrace deposits are, at best, limited aquifers. These deposits have a coarse <br />gravel - boulder layer at their base that tends to drain the deposits to the side slopes of the Animas <br />River Valley. The terrace deposits do not supply subirrigation to crops. The terrace deposits on <br />Ewing Mesa were historically used for dry land wheat farming. On Florida Mesa, south of U.S. <br />Highway 160, the terraces are commonly irrigated with water diverted from the Florida River for <br />the production of hay and sometimes other crops. <br />The alluvium of the Animas River is a regional aquifer located 400 feet below the main mining <br />operation. The alluvium is poorly sorted and coarse - grained, with ground water levels coincident <br />with the river level. The alluvial body thins and becomes narrow at the point where the Animas <br />River cuts through the Pictured Cliffs Sandstone and Fruitland Formation. <br />Ground Water Hydrology <br />Two aquifers are in hydrologic communication with the Carbon Junction Mine: the Animas <br />River alluvium (400 ft. downslope from the mine permit area) and the Pictured Cliffs sandstone <br />(subcrops beneath the mine pit area). <br />Monitoring of alluvial ground water has not been required at the Carbon Junction Mine. Animas <br />River alluvial water can be expected to have not been degraded by coal mining at Carbon <br />Junction because the less than 10 -acre surface area of coal spoil at the mine would not generate <br />enough leachate to overcome the dilutional effect of native alluvial ground water. <br />Bedrock ground water at the mine was monitored in well 95 -1 from 1995 through 2005. This <br />well presumably was completed in the Fruitland Formation and Pictured Cliffs sandstone. Well <br />95 -1 is located within the expected flowpath of any coal spoil leachate that would be generated <br />in the Carbon Junction backfilled pits. Monitoring data from this well did not show evidence of <br />leachate prior to 2006. The requirement to monitor well 95 -1 was eliminated in TR -13. <br />Elimination of this monitoring was based chiefly on: a) historical monitoring data from the wells <br />M <br />