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The Technical Revision indicates the quarry would like to process limestone that is removed by blasting during their <br />"investigation." There are a number of safety concerns and accessibility questions as to how that could be <br />accomplished. It is not feasible to get heavy equipment access in the rubble area where the limestone blocks will fall <br />if blasting of the hanging blocks is successful. Any grading on the rubble face could further destabilize the slope and <br />be potentially dangerous. Access by workers or manned equipment inside the head scarp is not recommended for <br />safety reasons. <br />There is no discussion on the technical aspects of the fill buttress proposed in Area H. Details should be determined <br />as to the engineering characteristics of the fill material, placement strategies, the increases in factors of safety, and <br />monitoring of the slide for both slope movement and potential rockfall that could impact work at the toe of the slide. <br />The Technical Revision appears to be primarily focused on stabilizing the northern portion of the slide. Exhibit 13 <br />indicates the fill section will only occur in the north end and removal of the yellow shaded area of the north block is <br />meant to "isolate the north and south ends" of the slide (from each other?). It is not clear what stabilization <br />measures will be attempted for the southern end of the slide beyond additional blasting of the south block. The <br />southern side of the slide continues to be unstable and as stated in the Technical Revision, "the size of the scarps <br />increases daily as the south end continues to move." <br />Recommendations <br />We have no compiling reason to recommend against approval of this technical revision but have questions <br />concerning the process. The condition of the quarry presents few options. As we stated in our earlier reviews, it <br />should be understood by the quarry operator and DRMS that these approaches may continue to result in no net <br />effect; or worse, a degraded stability situation where they have further destabilized the rockmass of the upper blocks <br />without the hoped-for failures (i.e., the blocks slide, break apart, and become incorporated into the rockslide rubble <br />zone below). <br />We offer the following observations and recommendations with regard to this Technical Revision: <br />Blast plans should be developed prior to blasting. <br />The plan on how the operator proposes to process the limestone generated by blasting should be more <br />specific and detailed. <br />Fill placed at the base of the slide in Area H should be adequately designed and placed in conjunction with <br />engineering recommendations to buttress the slope. Filling the hole will stabilize the movement of the <br />rubble zone but not necessarily the upper northern block any time soon. Safety measures to monitor both <br />slope movement and potential rockfall should be developed and implemented for this work. <br />The northern block of limestone remains unstable. Concerning the removal of the yellow-shaded area <br />(shown in Exhibit 13 of the TR), we point out that the shaded area does not correspond with the entire block <br />delineated by the original rockslide detachment scarp and the new scarp (see trend of yellow line on Exhibit <br />12 of the TR) that has now developed behind it. This may be a photo-annotation error. We would prefer to <br />see the entire block removed back to the new scarp (the yellow line). If that is not the case, post-blasting <br />evaluation will be needed of that portion of the northern block that will remain north of the yellow-shaded