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of the highwall will be sufficiently stable to protect areas outside the affected land from slides <br />and other damage. Please submit an appropriate engineering stability analyses, described <br />under Rule 6.5, for the highwall configuration proposed in the application. <br />Mc Stone Response #3: <br />From all outwazd appeazances the sedimentary Dakota Sandstone depositional bed to be mined is a <br />monolithic, highly indurated unit without apparent significant bedding or fracture structures. The stable <br />naturally occurring exposed steep canyon walls of Plateau Creek gorge are the primary evidence of such. As <br />extraction progresses from the Pre-Quarry to deeper within the sandstone bed any conflict with this <br />evaluation can be readily detected, and the plan for final finished highwall slopes at the extraction boundaries <br />can be accordingly altered to assure a stable situation. <br />To that end we propose conditional approval of the application-proposed near-vertical benched one-quarter <br />vertical to one horizontal ('/a:l) headwall slopes, dependent upon a structural evaluation to be completed and <br />reported to Division by the applicant/operator prior to the final extraction perimeter explosive shots. In this <br />way we can be assured of the absence of a heretofore undetected troublesome bedding or fracture plane that <br />would contribute to an unstable highwall. And if such anomalies are detected, the plan for highwalls to <br />remain shall be appropriately modified. <br />Adeouacy Item #4) <br />1. MG has completed a preliminary reclamation cost estimation totaling $16,193. The <br />reclamation cost estimation is based upon the proposed reclamation plan and several <br />assumptions. One of the assumptions is that the highwall would be scaled for loose rock (task <br />2). The enclosed reclamation cost estimation is preliminary and maybe revised after DMG <br />receives response to the adequacy issues raised in this letter. <br />McStone Comment #4 <br />Division calculations for the initial financial warranty value are acceptable to the applicant, with the <br />following clarifications. <br />Task #1 Weight scales are not intended to be used at the site, and aze not designated in the Mining or <br />Reclamation Plans. No other semi-permanent structures are intended to be constructed either. All <br />processing equipment is portable and shall be located at the site only seasonally before mobilizing it <br />for many other operation applications. <br />We therefore consider Task #1 to be un-necessary in the cost calculation for financial warranty. <br />**** <br />As verbally discussed with you earlier we wish to clarify that labeled "Permit Boundaries" in the three Plan <br />Map exhibits are considered to be the "Affected Land" areas, as defined by Rule 1.1(3). Labeled <br />"Excavation Limits" are intended to only reflect approximate extraction and operations area boundaries. <br />Peripheral disturbance between those two designations may occur from time to time. <br />You have been provided with copies of the US Army Corps of Engineers correspondence regarding <br />compliance with Corps 401 & 404 permit requirements. It has been established that compliance therewith is <br />not an issue at the proposed site. <br />The applicant has requested that we modify the address of record to assure that all correspondence is <br />invariably directed to the Corporate Secretary. I have therefore corrected and attached the title page and <br />Page 3 of the application form to reflect the official mailing address of ... <br />MCSTONE AGGREGATES, LLC <br />P.O. Box 483 <br />Cortez, CO 81321-0483 <br />