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Permit M77-424 Amendment 1 Exhibit D <br />Page 2 of 6 <br />percolation of precipitation and lateral discharge of groundwater. Mine water is collected <br />in a french drain system constructed in the floor ofthe L-1 drift and piped from the mine <br />to the Lower Bench vault. From the vault the pipe parallels the retort pipeline to Dry <br />Gulch where it discharges under NPDES Permit COG600452. <br />Retort water is water that enters the underground retorts (Retorts 4, 5, 6, 7 & 8) through <br />similar percolation processes as the mine water. The retort water is segregated from the <br />mine water through a piping system that collects retort water at the floor of each retort <br />bulkhead and diverts it to a single pipe that exits the L-1 portal in a buried trench adjacent <br />to the mine water french drain system. Both the retort pipeline system and mine water <br />system were re-constructed in the summer of 2003 using 2-inch diameter high density <br />polyethylene (HDPE) pipe. The new alignment resulted in a more stable location for the <br />retort drain pipe for the long-terns, as the former retort drain pipe was buried on the face <br />of the Lower Dump. <br />Sheets 1 through 8 of Exhibit D for this amendment show the plan and profile drawings <br />of the pipeline, the initial evaporation pond and 2 optional evaporation ponds. <br />Water Transmission Pipeline <br />The 2-inch HDPE retort drainage pipe extends from the sealed L-1 portal to the Lower <br />Bench flow-control vault, located on the Lower Bench approximately 100 feet from the <br />sealed portal. From the vault, the retort pipe trends north along the Lower Bench <br />approximately 20 feet west of the toe of the Upper Dump and down the north face of the <br />Lower Bench into Dry Gulch. From this point the pipe alignment trends down Dry Gulch <br />to the Oxy - BLM property line (neaz the center of Section 25 Township 7 South, Range <br />97 West), where it connects with the original steel 4-inch pipeline that transported oil and <br />water to the former Heater Treater facility (Area I5, Exhibits E and F in original mine <br />permit). The total distance of the 2-inch HDPE pipe to the property boundary is <br />approximately 1,800 feet. <br />At a location near the former Heater Treater and upgradient of the "Upper Manhole" <br />(manhole 15 on Sheet 7 of Exhibit D, Vol. 2) the 4-inch steel pipeline transitions to fl- <br />inch polyvinyl chloride (PVC) pipe that conveys the retort water westward along Logan <br />Wash Road, a distance of approximately 22,970 feet. At Manhole No. 7, just north of the <br />evaporation pond, the pipeline transitions to a 6-inch diameter PVC pipe and trends south <br />away from Logan Wash Road to the evaporation pond in S W 1/4 Section 29, Township 7 <br />South, Range 97 West, a distance of approximately 2,590 feet. <br />Fifteen manhole access vaults were constructed along the pipeline, nine of them between <br />the former Heater Treater area and the pipe's turn from Logan Wash Road to the <br />evaporation pond. <br />Visual inspection of the water transmission pipeline indicates that the 4-inch PVC pipe <br />was buried to depths of approximately 6 feet within Logan Wash canyon. Where the <br />pipeline turns south from Logan Wash Road to the evaporation pond, an inverted siphon <br />