Laserfiche WebLink
1 <br />Somerset Mining Company <br />' 1994 Annual Hydrologic Report <br />SMC responded with, "If any reduction in flow from the undermined <br />ephemeral drainages or springs is attributed to the effects of <br />' mining, and it is determined those reductions in flows are <br />depleting the flow in the North Fork of the Gunnison River, then <br />the operator will augment the flow in the river as required by <br />applicable State laws." <br />The Division included a discussion of the springs in the Proposed <br />Decision and Findings of Compliance for Permit Revision No. 2., and <br />in the Cumulative Hydrologic Impact Study - North Fork of the <br />Gunnison River (Revised 9/25/92). The CHIS states in parts: "The <br />underground mining operations, through subsidence effects, may <br />' reduce stream flows or flows from springs and seeps." "Streamflow <br />reduction could develop from three separate scenarios - increased <br />infiltration of runoff through subsidence fractures, direct stream <br /> recharge to the mine in zones of stream undermining, and loss of <br /> spring flow." "Despite the presence of subsidence features at <br /> several of the mine sites, this impact has not been identified by <br /> any of the monitoring programs." <br />1 " <br /> Streamflow may be diminished by a reduction in spring discharges. <br /> Decreases in spring baseflow to streams would be caused by <br />' interception of ground water sources by subsidence features. The <br />intercepted water would remain within the North Fork of the <br />Gunnison drainage basin, but the location of surface contributions <br />' could be altered. Three mines in the CHIS area monitor springs and <br />seeps for possible subsidence impacts from mining - Hawk's Nest, <br />the West Elk Mine, and Orchard Valley. Hawk's Nest recorded no <br />changes in flow while they were operating, and currently they do <br />' not monitor flow." <br /> Due in part to a change in personnel at SMC, the practicable <br />' beginning of the 1993 spring monitoring commenced at the end of <br />June. In order to make up for this oversight, the required spring <br />monitoring was extended through June of 1994, as included in <br />' Technical Revision No. 18. During the review for Technical <br />Revision No. 18, the Division required the baseline analysis to be <br />conducted, submitted, and approved prior to mining within the angle <br />of draw of Springs 1-11. SMC agreed not to perform secondary <br />mining under Springs 1-11, and subsequently agreed not to mine <br />within the angle of draw of Springs 1-6 or Springs 10 & 11 until <br />the baseline monitoring and interpretation of data is complete and <br /> approved by the Division. Spring monitoring data for Springs 1-11 <br />' are included in this report. <br /> When the present spring monitoring was begun in June 1993, effort <br /> was made to locate the springs as marked on the Monitoring Location <br /> Map from Western Slope Carbon Hawk's Nest Mine included in the <br /> permit documents as page 2.04-50xviii. The legend indicates the <br />' 10 <br />