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• in Table 5, Results of Water Quality Analyses Samples from F~dsting Wells and Monitoring <br />Wells. It will be noted that virtually all the water is a sodium sulfate type, which is extremely <br />unusual. This results from the presence of sodium bicarbonate minerals in and adjacent to <br />the coals. The high sodium content of the water would be harmful for those with heart <br />problems, while the high sulfate concentration would produce a strong laxative effect on <br />anyone not used to drinking this water. <br />A series of water quality samples were collected from various coal seams in mines by the <br />USGS in 1949, and reported in Colorado Groundwater Basic Data Report No. 4. These <br />findings indicate that groundwater in the coal seams is generally is not suitable for <br />consumption, due to the high total dissolved solids and high sulfate concentrations. <br />Groundwater recharge occurs in the pinyon-juniper covered hills to the west of the permit <br />area. Within this area, potential elevations of the water table are essentially identical in <br />each coal seam, indicating a transport regime within a transport region within the <br />groundwater flow regime. This is locally modified in those areas where underground mine <br />workings have resulted in drainage of part of the groundwater. In these cases, overlying coal <br />seams tend to have a higher hydraulic potential and result in the downward vertical <br />movement of groundwater from the upper zones into the deeper portions. In some areas, <br />such as the northern part of the permit area, groundwater transport in the mine workings <br />results in surfacing of contaminated groundwater at the colluvium sediment interface, <br />followed by infiltration of this contaminated groundwater into the underlying Trinidad <br />• Formation. This has resulted in a severe contamination of Trinidad groundwater in the area <br />immediately north of Gordon Wash, where a sample from Well 306 contained 12,159 mg/1 <br />TDs and 7698 mg/1 sulfate. <br />With the exception of wells which penetrate old mine workings, the monitoring wells <br />generally produced low yields of 2 to 8 gallons per minute (GPM). A pump test conducted <br />in the lower coal seams, upstream along the north side of Gordon Wash, resulted in a <br />calculated transmissivity of 0.79 gallons per day per foot (GPD/ft) over a 60 foot perforated <br />interval, or an average permeability of 0.013 GPD/ft'. Based on the electric log, it appears <br />that the bulk of the water production comes form the Cameron, Lennox, and Walsen coal <br />seams, which have an aggregate thickness of approximately 15 feet in the area. If this were <br />the case, the average coal permeability would be 0.053 GPD/fP. Thus, the aquifer is of a <br />very limited usefulness with regard to either quality or quantity. <br />Surtace Water <br />The mine plan area is drained by two ephemeral drainages, the Maitland and Gordon <br />arroyos. The location of these drainages is indicated on the Hydrology Map (Map 4). <br />Water flows in these drainages only in direct response to precipitation in the immediate <br />watershed or in response to rapid snow melt. <br />• <br />2.0438 <br />