2003-06-09_REPORT - M1977211 - Laserfiche WebLink

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Integration of Layback and Enhanced Amendment Plans Pikeview Quarry Feb~aryE2,' VED JUN 0 9 2003 Background Division ~f Minerals and Geology In the mid-1990's an amendment was approved for the Pikeview Quarry that included the Enhanced Reclamation Plans. This amendment modified the mining plan to remove previously permitted lands and substitute an over-excavation hole at the base of the quarry backwall. Mining progressed since that time primarily under the direction of the late Greg Francis. However, mining did not progress to the point where the over-excavation was actually begun. At the time of the development of this integrated plan there was still a considerable amount of limestone to be removed at the base of the quarry backwall before the over-excavation is actually started. The over-excavation was referred to as Area H in that amendment and that name is carried over into this plan. Late in the 1990's consideration was given to laying back the backwall of the quarry to produce a more reclaimable surface and configuration and to remove much of the remaining limestone forming the current backwall of the quarry. The problem with that limestone is that it is highly unstable due to the steep (34 degree) dip of the rock away from the mountain. Although bench reclamation methods have been changed since the Enhanced Reclamation amendment and that has considerably improved stability where that was used, all the old mining benches remain in a highly unstable condition. Reclamation of those old benches without drastic modification is probably not possible. Therefore, the Layback amendment was developed and approved. In 2002 the Layback was started on the most southerly of the two peaks involved in that plan. It began here because of ready access to that land. Granite produced from the excavation of this initial Layback work was pushed over the quarry face and formed a long talus slope that ended on the bench below the backwall and more or less in the middle of the quarry. By late 2002, work on the quarry began to encounter problems with this Layback work. In brief, the problem was twofold. First, there was a lack of room to dispose of the material coming from the Layback work without contaminating the limestone. Second, continued excavation of limestone to reach the Area H elevation (about 7250') was becoming increasingly difficult without creating difficulties in the haulage of the limestone to the processing plant. Near the end of 2002, Mark Heffner and BJ Fuller were asked to examine this situation and see if a solution could be found to alleviate these problems.