1992-06-09_REPORT - M1977378 (3)

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SUNNYSIDE BASIN (LAKE EMMA) AREA - Plate No.2 The waste rock stockpiles were treated with ProMac during July and October as committed to for mitigation of acid production from the temporary waste stockpiles that were generated by open -pit mining in 1988. This should be the last ProMac treatment required because the current plan is to fill the Lake Emma hole during 1992 according to TR -06 (approved in September of 1988). In order to facilitate the filling of the Lake Emma hole in 1992, a haul road was constructed during September - October, 1991. This haul road circles the hole. The subsidence points located above the Washington Pit and Sunnyside Pit were monitored for movement. There does not appear to be any movement of the slopes according to the survey data. A copy of the results are included in the Appendix. The vegetation Test Plot was not evaluated by Tom Colbert of IMS during 1991 but mine personnel did monitor the Plots during 1991. There is no substantial change from 1989. The vegetation that is growing on the plots is sparse but appears to be healthy. Planned Activity for 1992: 1) Fill the Lake Emma hole according to TR -06. This project will probably not be completed in 1992 due to ice buildup in the hole that cannot be eliminated prior to filling. Because of this, it is probable that additional grading and placement of the sealing layer and overburden will be required in the future instead of project completion being accomplished in 1992 as previously thought. 2) Attempt to divert ground water around the hole by interception at the overburden /rock contact. This will be evaluated during construction (filling the Lake Emma hole) for feasibility. If it appears feasible but requires a deviation from the accepted plan, a TR will be submitted for approval. 3) Grade the remaining disturbed area (ie: Sunnyside Pit, Washington Pit and Sunnyside Basin) and repair the Little Mary subsidence. These projects will be done on an as time and equipment is available basis and might not be completed in 1992. The filling of the Lake Emma hole will be the priority project for 1992. 4) Monitor the subsidence points if the reclamation of the pits does not occur in 1992.