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1 <br />' locations in the mine that produce water over the long tens. Most wet areas encountered during <br />mining flow for relatively short periods (hours or days), in the form of profuse drips, and then <br />gradually dry out as the flow stops and the ventilation air carries the moisture out of the mine. <br />These areas are generaly associated with stackrock in the roof. Stackrock is a sandstone <br />laminated with very thin layers of silty carbonaceous material. These laminations range in <br />thickness from a few inches to a tew millimeters thick. Water in the stackrock appears to be <br />connate in origin and not from the rechargeable groundwater systems. Yrtually all of the geologic <br />water enters the mine from the surrounding strata from broken rock in the gob behind the longwall <br />face. <br />' The smallest quantity of water entering the mine is the incidental category. This category includes <br />leakage from water lines, dust control watering in the haulage entries, and washdown water used <br />in the slope and other locations. <br />Oytg_oing Watar As coal is mined, it is wet by dust control sprays on the continuous miners, the <br />longwall shearer and at transfer points along the conveyor belt system. This water is then carried <br />out of the mine as surface moisture on the raw coal. This added coal surface moisture represents <br />' a 2% increase in the raw coal moisture content. The raw coal tonnage produced during this <br />reporting period was 1,254,089 tons. <br />Water leaving the mine as ventilation humidity represents a large quantity in the water balance. <br />The temperature of the exhaust ventilation air is almost constant, ranging from 60° in winter <br />months to 63°F in summer months. The relative humidity of this air ranges from 80% in the <br />summer to 95% in January and February. Throughout the year, except for the months of June, <br />July and August, the ventilation air is warmed as it passes through the mine. This increases its <br />moisture carrying capacity and the air picks up considerable quantities of moisture wherever there <br />is water available. During the summer months the air is actually cooled, however, the difference <br />in relative humidity still allows the exhaust air to carry away more moisture than is brought in with <br />the intake air. <br />Some of the water entering the mine is collected in sumps at various locations. In the past, this <br />water was eventually pumped out of the mine through the Fist Intake or to process pond two <br />(PP2). All water discharged from the mine is now discharged at the sump dewatering holes shown <br />' on Plate 1. During this year approximately 84% of the total was discharged from SDH-2, and 4% <br />from SDH-3 and 12% from SDH-5.. This water is further discussed in the next section. <br />2.2.2.6 NPDES Discharges and Whole Effluent Testing At present, Western Fuels-Utah has <br />15 NPDES ouffalls. Six of these ouffalls have never experienced a discharge and a seventh has <br />had one discharge since construction 12 years ago. The vast majority of water is discharged from <br />' 12 <br />!1 <br />