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West Elk Mixe <br />Estimated percent changes in North Fork flow volumes due to withdrawals for projected mine <br />requirements are provided in Table 48. Even in a drought yeaz, the mine water requirements <br />• anticipated during term of permit are only about 0.1 percent of the North Fork flows. Thus <br />fisheries, streamside vegetation, and sediment transport process would be unaffected. <br />Furthermore, anticipated changes in river flows due to withdrawals would have no effect on <br />sub-irrigation or flood irrigation of alluvial valley floors on the North Fork downstream of the <br />mine. <br />An important factor to consider relative to Table 47 is that fault inflows to the mine are not <br />accounted for, yet a significant amount of mine water is actually discharged to the North Fork, <br />thus offsetting MCC's depletion. In 1996, MCC actually was a net exporter of water from the <br />mine to the North Fork (+157 AF) with the contributions of the B East Mains fault inflow. <br />Table 49 contains actual and projected water usages for the West Elk Mine. These numbers <br />are projections for abuild-up of tonnage and increases in water usage which dare entirely <br />dependent on coal sales and market conditions. <br />Table 47 Estimated Percent Change in North Fork Flow Volumes <br />Annual North Fork TotalYolume Net Net Depletion <br />StreamtlowCase' (AF) Requirement Requirement 63 AF <br /> 88 AF 70 AF <br />Average Yeaz 313,000 -0.03 -0.02 -0.02 <br />I in 25 dry Yeaz 142,300 -0.06 -0.05 -0.04 <br />(e.g.1954) <br />1 in 100 dry year 82,270 -0.11 -0.09 -0.08 <br />(e.g.1977) <br />Cases considered aze water yeazs (i.e., October through September). <br />Sedimentation Ponds Management -The fresh water pond (FRr-1) receives North Fork water <br />from the raw water intake gallery. From FW-1, water is either diverted to the water treatment <br />plant for domestic purposes or it is conveyed to a 1.2 million gallon raw water storage tank <br />that is located to the south of the main mine facilities and west of the Sylvester Gulch Facilities <br />Area. Water is then used for both longwall mining operations and continuous <br />minerldevelopment mining operations. Within the mine, water is used for dust suppression <br />and for the hydraulic equipment associated with the longwall and continuous miners. <br />Of the five sedimentation ponds, three ponds (MB-3, MB-4, and MB-5) receive only local <br />runoff and water from facilities washdown operations. In contrast, MB-1 and MB-2R can <br />receive mine water discharge, in addition to local runoff. Consequently, Ponds MB-1 and <br />MB-2R have the lazgest capacities at 13.3 and 14.6 acre-feet, respectively, and are the focus of <br />the remaining discussion. <br />~~• <br />2.05-181 Revised/un. l995 PR06; Revised Nov. l9987R80; 1/-8 PR08 <br />