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Re: DRMS Annual Report MLRB 1978-208 <br /> From MooresJ <br /> To M Cunningham Sr Environmental Manager, Department Director <br /> Department of Natural Resources <br /> Division of Reclamation Mining and Safety Sent by email <br /> 11/30/18 <br /> ADDENDUM TO EARLIER INSPECTION REPORT RESPONSE <br /> INFORMAL Notes and observations regarding the stability and performance of the highwall relative to <br /> the original design criteria,and comments on the geological characteristics of the developing deposit <br /> beyond the advancing highwall. <br /> I note that you should have in your possession the detail regarding the highwall,the topo and the <br /> technical revision with the weed plan,and of course the signage was addressed some time ago, in the <br /> possession of the DRMS at this time,these matters arising out of the January 28 2018 inspection earlier <br /> this year. I would really appreciate confirmation of those documents together with any comments or <br /> approvals to make sure they conform to your expectations. I am happy to send those also, however <br /> given the size of the documents(some of the attachments were dating back to the original 1979 <br /> drawings) may I offer them in a cloud based format such as drobox?They seem to be a little too large <br /> for conventional email <br /> I spent quite a bit of additional time fine tuning the highwall configuration in order to demonstrate the <br /> benches present as stipulated in the planned mine design presented to the Division and under the <br /> Divisions recommendations approved by the Board in 2006.We have seen a broad degree of success <br /> with this geometry and the indications from a brief analysis I conducted recently are that the highwall in <br /> performing in excess of the anticipated minimum standards as outlined by Alan Howard, Brierley and <br /> Associates, in his 2006 geotechnical report. Much of this can be explained as the competency of the <br /> material is significantly improving,as we had anticipated it would,as the highwall advanced through a <br /> weathered superficial lawyer of the migmatized granite, into the more solid,competent,homogeneous <br /> and structurally consistent, more felsic matrix, and one sees a greater percentage by volume of the Pikes <br /> Peak Formation,characterized by a lighter pink matrix, heavily mineralized with well-developed slower <br /> cooling quartz crystals which form a strong, durable component. <br /> We further note that there is no apparent structure exposed in advance of nor by the advancing <br /> highwall.Any foliated lithology,where this is still chiefly present in the Idaho Springs Formation,is <br /> superficial or non-occurring through the complex undulating folds of the complex interface between the <br /> two lithology's,and the interstitial matrix is sound, dense and relatively neutral or <br /> characteristically very hard,typically moderately to highly abrasive, uniform,free from deleterious <br /> mineralization's and other alterations,, resistant to weathering upon its surface exposures,with a less <br /> apparent dip/strike as the blocky or laminated character of the deposit to the west s gradually absorbed <br /> by the contact area. <br /> In conclusion,we are very happy with the manner in which the highwall has performed based upon the <br /> initial design criteria from 2006,and satisfied that the highwall is stable, and not yielding materials in <br /> any type of uncontrolled manner based on our observations.We check the stability of the exposed face <br />