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ii iiii ii iii i 999 iiiii-iii STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY DepartmeN of Naluml Resources 7l l7 Sherman $L, Roont Denver, Colorado BU2U7 ? 1 5 DIVISION O F Phone: 1703) 066 35fi7 MINERAL S FAX 1703103'_-8105 be DATE: September 1 1999 -~\ G E O L O G Y , , ~1 \ RECLAMATION I MINING•SAFETY TO: Sandy Brown II ' Bill Owens FROM: Jim Pendleton ~_= ~'" ~' eovemor Greg E. Walther E.ecWrve D~reUOr RE: Edna Mi andsl' a -Field Trip Observations Michael a. Long ,k er o: C-80-001) D,vsion D,renor We examined the small surficial landslide near the top of the Goat Trail Ridge. The slide occurred along the alignment of the old conveyor, which was removed during reclamation several years ago. The footprint area immediately adjacent to the Goat Trail Road was regraded and subsoil and topsoil were applied, followed by reseeding. It appears that during the following spring the topsoil slumped, resulting in a series of small head scarps. It appears that movement has not recurred this spring. The small extensional scarps have begun to heal in many ]ocations. The scarps have begun to weather, which has subdued their expression. No standing water was observed. However, several small areas within the extensional scarps appear to be undrained. During precipitation events and snow melt these may pond water and promote infiltration into the landslide mass. Contrary to my earlier suspicion, it does not appear that this slide was related to any ground water or surface water migration from the adjacent Shop area. In order to completely repair the landslide it would be necessary to excavate the entire area and redeposit the material in lifted fashion. The disturbed azea necessary to accomplish this remedial project would significantly enlazge the area of the surficial landslide. It is also possible that failure would recur. Further, examination of the Goat Trail area from the road in the adjacen[ valley determined that the azea in question is not out of character with many undisturbed and disturbed areas in the surrounding area. In my opinion the optimum treatment for this small landslide involves the minimum redisturbance necessary. I recommend that Pittsburgh & Midway hand treat the small undrained areas. Close any open cracks by hand raking or shoveling, and create a daylight drainage path for any closed depression. Inspect the drainage of the Goat Trail to ensure that no road drainage is directed onto the effected area of the landslide. cc: Lany Routten dot: M:\COALUAP\ednatrip.wpd JP/jP