2006-05-12_REVISION - M1977342 - Laserfiche WebLink

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allowed Henderson to significantly refine mapping points and acreages within the property boundary. Considering that the initial maps submitted for the permit in 1977 and those submitted for AM-O1 were hand-drawn, this new mapping is a significant step forward. In refining the mill site maps in preparation for siting a new interceptor canal at the ultimate up- gradient location of the tailings impoundment, Henderson quickly noted that the Affected Land boundaries were inconsistent and inaccurate in a number of areas. The 3429 Affected Land acres (3550 total acres less 121 acres for the mine site) calculated by the DMG upon approval of AM- 04 is 97 acres short of the accurate total. These additional acres are buffer are located primarily in the area of the tailings impoundment also are scattered throughout the mill site area. The new Affected Land map is presented in Exhibit C. There is no change in the mine site map or the mine site Affected Land acreage at this time. 2.2 Interceptor Canal The ultimate interceptor canal is noted on the new map in Exhibit C. The proposed canal is to replace the existing tailings impoundment interceptor canal that will be inundated by natural expansion of the impoundment over time. The purpose of the interceptor system is to capture fresh water runoff from the Williams Peak Range and gravity-flow it around the tailings impoundment, delivering the intercepted fresh water to the Williams Fork River, unaffected by Henderson operations. The canal will be primarily of earthen construction, with the exception of areas where existing slopes are too steep to construct an earthen channel. At those locations, the canal will be routed into HDPE piping to prevent slope failure. The proposed canal will be approximately 4.7 miles long, beginning at Ute Creek and ending at the existing outfall, near the crest of the northern edge of the tailings impoundment dam. The canal and associated maintenance road will average 40' wide and will disturb a total of 23 acres within the Affected Land area. This canal is being designed so that another canal will not haue to be constructed. More specifically, this canal will be operable until the final elevation of the tailings impoundment is reached. Other than the location and the increase in both disturbance and total Affected Land area, Henderson is not seeking specific approval of the canal under this Amendment. Henderson considers this proposed interceptor canal to be an Environmental Protection Facility (EPF) per the Environmental Protection Plan referenced in Exhibit T. As such, Henderson will submit the plans and specifications for the EPF under separate cover as required by Rule 7.3 of the Mineral Rules and Regulations of the Colorado Mined Land Reclamation Board for Hard Rock, Metal and Designated Mining Operations (Rules). A U.S. EPA Section 404 permit application for the canal presently is under review by the U.S. Amy Corp of Engineers. 2.3 Xcel Energy Easement Deletion 4