2009-02-23_INSPECTION - M1977211

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Page 2 opportunity because I did not feel confident that I was qualified to do that plan. When I reviewed the plan, 1 did express a concern about the lack of connection to adjacent areas to the south and to Area H which was still in the plan and carried over from the 1994 amendment which I prepared. Perhaps of greater importance though is the fact that after the layback plan was begun it was realized that MSHA would not allow mining at the top of the quarry backwall in the Forest Service land or lower on the backwall while mining immediately below at the base of the backwall. That is, the two mining areas had to be offset for safety purposes. This created a situation where quarry floor mining had to move back and forth while staying out from under the higher elevation mining. All of this back and forth motion on the quarry floor was begun long before the top elevation of Area H was reached. Once Area H was reached, that back and forth motion had to continue to produce adequate volumes of limestone to meet customer requirements. The effect of this was to slow the progress on the layback because often it had to simply stop while a portion of the floor was mined. In effect, everything became horribly unsynchronized between the quarry floor and the layback progress. Whether this would have been addressed if the layback amendment had looked at more than just that area cannot be determined, but, in my opinion, if the layback plan had looked at the linkage aspects to other portions of the total permitted plan this difficulty might have been addressed. I'm not certain it would have ultimately changed anything, but it is possible that it might have been recognized that at some point there would be a great deal of load high on the backwall relative to the amount of support on the floor. But that is hindsight. With regard to the questions on the influence of TR-11on the propagation of the slope failure, in my opinion, they are not closely related. Keep in mind, until last week when you pointed out this technical revision I did not even know of its existence. I obtained it from the permit file disk Jim Dupler prepared for me and have carefully examined that revision. It is true that TR-11 allowed an alteration of the benching in the south end to have higher walls relative to the bench. That might not have been the best idea, all things considered. But, looking at the first photo, one can see the effect of TR-11. That area includes the narrow "canyon" in the foreground and that zone ends at the point where the "canyon" opens to the quarry floor. The northern edge of TR-11 is at about the near side of the large pile of rubble at the entrance to the "canyon." The floor of TR-11 is visible where the small road is in the "canyon." Thus, the lowest elevation in TR-11 was above the top elevation of Area H whose south boundary is somewhere in the middle portion of the rubble pile at the mouth of the "canyon." Although support was removed in the TR-11 area, the dip of the rock here is about 4 degrees so sliding on bedding plane joints in the limestone would have been minimal, as pointed out by Dr. Abel. Elsewhere the dip is about 32 to 34 degrees to the east and approaches vertical right at the fault zone where the Paleozoic sediments contact the PreCambrian granite. Nevertheless, there does appear to be some small amount of cracking on the benches at the top of the TR-11 area. Rather than sliding cracks, these may be separations due to the limestone below the south peak moving somewhat downward and rotating clockwise significantly after the middle of the quarry slid down. But clearly, if there is cracking in the TR-11 area as a result of the overall slope failure then the west side of the TRA 1 area has suspect stability at this point. Hopefully, these two photos will help to illustrate the nature of the relationships and will help answer your excellent questions regarding these features. Sincerely, 7 Mark A. Heifner cc: Mac Shafer Jerald Schnabel