The Urad Mine produced molybdenum concentrates from a low-grade ore body from the early 1960's through 1975, after which the mine and tailing facilities were reclaimed. The facilities were owned by Climax Molybdenum Co., located in the upper reaches of the Clear Creek basin west of Golden at 10500 feet msl elevation.
W. W. Wheeler and Associates, Inc. was retained by Climax in 1990 to provide a hydrologic evaluation of the Woods Creek Basin pursuant to obtaining a NPDES discharge permit for the tailing subdrain water that flows from the tailing impoundments. A subsequent project in 1990 included a comprehensive geohydrologic and geochemical characterization of one of the two tailing impoundments. Wheeler provided overall project management for the study and subcontracted with others for geotechnical evaluations, exploratory drilling, and geochemical evaluation.
In 1991, the scope of work included design and construction observation for a collection system to convey the subdrain flows to two designated outfall locations and to bypass the streamflow of Woods Creek around the mine area. The collection system was constructed on a fast-track schedule and was completed in late 1991.
The scope was also extended to include the design and construction observation for a pond-type treatment system to remove metals from the acidic influent to comply with a CDPS discharge permit from Colorado and a permit from the EPA. The treatment system performed beyond expectations and additional improvements were designed by Wheeler to provide back-up facilities. Mechanical treatment has since replaced these settling ponds and the ponds have been enlarged for surge storage.
Wheeler provided all design evaluations, construction drawings and specifications, and permitting and follow-up support for the Urad projects, except for electrical engineering. Included in the design were hydrologic reports used for negotiating the CDPS discharge permit and obtaining CWA Section 404 Nationwide Permit authorizations.
