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Henson Creek Mines - Ute Ulay Mine

 
Site Contact:
Steven Way
OSC

(Way.Steven@epa.gov)

Site Location:
Engineer Pass Road
Lake City, CO 81235
 response.epa.gov/UteUlayMine

The Ute Ulay Mine and Mill Site is an inactive gold, silver, lead and zinc mining and milling operation located near Lake City, Colorado. The Site includes a flotation mill with mixed tailings and waste rock piles, several open portals and shafts, a sub-economic ore pile, and tailings impoundments. The mine and mill tailing and waste rock piles are situated adjacent to Henson Creek. The tailing and waste rock piles are located on both privately-owned and Bureau of Land Management (BLM) lands at the Site.

The most significant hazard at the Site is the potential for catastrophic failure of the mine waste rock dump and mill tailing impoundments into Henson Creek. The stability analysis demonstrates that slope failure is likely under extreme loading events such as an earthquake or rapid drawdown of contained water, and that slopes are only marginally stable in their existing conditions. The removal action involves re-grading and amending an estimated 20,000 cy of waste rock and 15,000 cy of tailings.


Ute Ulay mine and mill waste dump and Henson Creek from the west looking east. Ute Ulay mine and mill waste dump with avalanche that dammed Henson Ck eroding waste into the creek. Lower Tailings Impoundments Upper tailings impoundment Moving the sub-economic ore pile to create a mixing area. Continued consolidation of sub-economic ore pile with equipment. Improved and widened access road from Engineer Pass Road. Flume pipeline and other mining metal remnants awaiting relocation from the tailings impoundment. Continued consolidation of the waste rock and sub-economic ore to create a work space for mixing. Creating the mixing pad beneath the former footprint of the sub-economic ore pile. Ramp from mixing area into the tailings impoundment showing berm to contain site runoff. Shot of the tailings impoundment slope beneath the flume and cribbings structure. View looking west along the slope and constructed flume holding back the tailings impoundment. View of cribbings structure installed to hold back the tailings impoundment. Another view of the cribbings structure and the bedrock outcrops holding back the tailings impoundment. Slope and tailings impoundment debris. View looking east along the tailings impoundment slope. Cribbings structure holding back the tailings impoundment on the southeast corner. View of slope, including rock outcrops, beneath the tailings impoundment. Another view, further down the slope, of the face beneath the tailings impoundment. Tailings impoundment and access road during excavation and backfill operations. View of the SE corner of the tailings impoundment from across Henson Creek. Bench of native material is shown along with depth of tailings. View of the SE corner of the tailings impoundment from the top of the bench above the haul road, showing the depth of tailings behind the bench. Another view of the depth of tailings behind the bench along the south side of the tailings impoundment. View of the bench and the excavated area in the SE corner of the tailings impoundment as excavation underway. View of the excavation of the SE corner of the tailings impoundment from the bench, looking north. Wall on the left side of the photo is approximately 12-16 feet high. View of the bench and bedrock elevation relative to the top of the tailings impoundment from across Henson Creek. Another view of the SE corner of the impoundment from across Henson Creek. View of the cribbing structure sitting atop the bedrock layer at the narrowest point of the impoundment where no berm was possible. The cabin is shown in the background. This is the angle that would have the notch in the impoundment to accommodate the cabin. Larger view of the cribbing structure, the adjacent bedrock layer, and the location of the notch in the slope leading up to the cabin. Close-up view of the cribbing structure from across Henson Creek. Overview of the site from across Henson Creek Tailings impoundment panoramic photo from across Henson Creek. View of the cabin, the cribbings structure, and the bedrock cliffs adjacent to Henson Creek. Larger view of the tailings impoundment, cribbings structure, cabin, and repository construction. Another view of the cleft in the rock and the potential drainage feature profile for the repository. Close-up view of the cribbings structure and drain pipes to the west along the south side of the impoundment. View of the cribbings structure and the cabin behind it. Overview of the site and the lower Henson Creek drainage beyond it to the east. Cabin and placed material mix along the road into the site below Engineer Pass Road. Site overview from across Henson Creek, looking north, and the mixing area. Fortification of the berm and drainage along base of the repository Grading and compaction of the lower slope of the repository East view from shop level to the eastern end repository / former tailings impoundment Upper tailings impoundment excavation. Upper Impoundment - tailings berm and bedrock surface exposed at creek edge. Ute Ulay - east end viewing west on toe ditch. , Ute Ulay - creek level East end looking west. , Final grading and finishing of the slopes The repository was graded to slope away from Henson Creek. The impoundment in front of the mill was amended, filled and graded. Another view of the repository taken the day EPA demobilized from the site. EPA, CDPHE, BLM, and the Hinsdale County conducted a walk through of the site on July 25, 2013. The Ute Ulay Mine and Mill with a new repository! The Ute Ulay Mine and Mill repository. The Ute Ulay Mine and Mill with a new repository! Regraded repository slopes looking east (downstream) from upper level site road. Site access road and rocked berm looking west. Mid-slope road access looking west with final rock cover on both slopes. Lower slopes at west end of site looking east. Final rock cover with both borrow and onsite screened rock cover.
For additional information, visit the Pollution/Situation Report (Pol/Sitreps) section.