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Stream Buffer Zones - <br />No disturbance is anticipated within 100 feet of a stream with a biological community. <br />Probable Hydrologic Consequences- <br />Ground Water - <br />The Bowie No. 1 Mine has the potential to affect ground waters in three ways - <br />degradation of water quality, none consumption of water, and dewatering of <br />insignificant bedrock aquifers. Each of these cases will be discussed in detail in the <br />following pazagraphs. <br />Degradation of ground water quality could occur in three locations. The train <br />loadout and auxiliary coal stockpile are located on an alluvial terrace of the North <br />Fork of the Gunnison. Runoff infiltration could result in the dissolution of salts. <br />The operator installed and monitors three wells downgradient from these facilities <br />and has not detected any significant water quality changes. The Division has <br />expressed some concern about the narrow band of alluvium found downdip of the <br />underground waste development stockpile. The operator has installed a well (Node <br />22) and is monitoring that location for impacts. No impacts have been detected to <br />date. Lastly, there is a slim probability that subsidence-related impacts to springs <br />might result in the modification of springs water quality due to a change in routing <br />of the water. The operator is monitoring springs in currently affected azeas <br />quarterly for major cations and anions, and no changes have been detected. <br />Water utilized for mine operations is obtained from a well in the Steven's Gulch <br />well field. Consumption from this alluviaV colluvial deposit is measured with a <br />wellhead gage. From July 1990 through June 1991, Bowie Resources Limited <br />produced 720,000 tons of coal and imported approximately 18,000 gpd from the <br />Steven's Gulch well. Water quality information is also collected and reported to the <br />Division. In 1986, CWI produced 333,292 tons of coal and consumed 8,700 gpd <br />while in operation. In 1983, the Bowie No. 1 Mine produced 1.3 million tons of <br />coal and consumed 27,400 gpd. There has not been any detectable impact to the <br />groundwater/surface water regime in this well field since they initiated pumping at <br />the site. <br />Dewatering will occur at the Bowie No. 1 Mine but will be insignificant in extent. <br />Mine inflows may be derived from fractures associated with perched aquifers <br />within the overlying Mesaverde, surficial alluviaUcolluvial sediments, and stream <br />flows associated with fracture systems as well as from dewatering of the coal <br />aquifer itself. In 1983, approximately 300,000 gallons of water flowed into the <br />mine from perched, discontinuous, water-beazing sandstones overlying the D seam. <br />A Division inspection in March 1986 documented inflows of 200 gallons per day. <br />This inflow gradually slowed once this perched aquifer was completely dewatered. <br />30 <br />