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II. DESCRIPTION OF FACILITY <br />The Henderson mill operation stores and uses petroleum products and <br />"hazardous substances" (as defined by amendments to the Clean Water Act) <br />in the processing and milling of molybdenum ore. <br />MILL, CRUSHER, CONCENTRATOR, and TAILING DISPOSAL SITE <br />The mill site (Figure 1 } is approximately 22 miles south of Parshall, Colorado <br />just off Grand County Road No. 3. The ore processing facilities (mill, cn~sher, <br />and concentrator) are located on the western slope of the ridge between the <br />Williams- Fork River and the east branch of Ute Creek, Grand County, <br />Colorado. Also present in the vicinity are the mill water and potable-water <br />reservoirs, mill water storage tanks, gravel pits, gravel storage area, tailing <br />deposition area with seep water entrapment canal, and runoff diversion <br />canals. <br />Conventional crushing and semi-autogenous milling circuits are used to <br />reduce the size of the ore and liberate economic minerals for collection and <br />concentration by flotation. Approximately four or five pounds of molybdE~num <br />disulfide (Mo52) concentrate are extracted from each ton of ore. The <br />remaining 1,995-6 pounds are waste in the form of fine silica sand which is <br />transported by gravity in a water slurry to a tailing deposition area north of <br />• the mill site. All water used to transport the tailing is decanted frorc~ the <br />surface and returned to the mill for reuse via a completely closed loop <br />industrial water circuit. <br />Process water discharges are allowed under the terms and conditions o1` the <br />CDPS permit. The discharge is only used in cases of extreme storm or runoff <br />events, bypass system failure, or near exceedance of the process water <br />system volume that jeopardizes the integrity of the tailing impoundment. <br />Weekly samples are required during a discharge and if a visible sheen is <br />present, the samples will be analyzed for oil and grease. <br />The Henderson mill site is located solely in the Ute Creek drainage, and any <br />spills of any material will be prevented from reaching the Williams Fork Fiver <br />by the tailing dam. A seep-water entrapment canal downstream from the <br />tailing dam further insures against any spill entering the waters of the state. <br />Intermittent flows from Ute Creek and its two tributaries either bypass the <br />industrial water cycle or supplement it as allowed by water rights. The <br />drainage system is capable of handling stormwater collected in secondary <br />containment to prevent discharge of contaminated stormwater into surface <br />water. <br />• Molybdenum disulfide (MoS2) concentrate is transported by truck or truck <br />and rail combinations to domestic processing plants or a port for overseas <br />shipment. <br />Page 2 <br />