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1 <br />LJJ SARE <br />AND ASSOCIATES, INC. <br />G-led irnl 6-0 Bering Conmll.1 <br />A <br />'), "h e 1 -- o " <br />Canururnon Aratertdr T"dat h 1ntpldioa <br />January 17, 2007 <br />Mr. Norbie Larsen <br />Larsen Colorado LLC <br />P.O. Box 670 <br />Penrose, Colorado 81240 <br />Subject: Review of Plans for 112 Permit <br />Byzantine Quarries <br />Fremont County, Colorado <br />Project No. D06.287 <br />Dear Mr. Larsen: <br />As requested by Mr. Jack Clark, Joseph A. Cesare and Associates, Inc. /Construction <br />Technical Services (hereinafter referred to as JAC /CTS) has reviewed the Plans submitted to us <br />for the 112 Permit for the Byzantine Quarries (undated). R. C. & T. R. LLC Surveying prepared <br />the Plans. We have reviewed the plans for general compliance with the recommendations in <br />our report, "Geotechnical Stability Exhibit, Byzantine Quarries, Fremont Colorado ", Project No. <br />D06.287.A, revised December 20, 2006. <br />In our report we state that for long term stability pit walls oriented within 20 degrees of <br />the strike of the bedding plane should be sloped at approximately 1.6 Horizontal (H):1.0 Vertical <br />(V) and that pit walls that are oriented at greater than 20 degrees to the strike of beddings can <br />be sloped at approximately 0.5 H: 1.0 V. The Plans reviewed indicate a Phase I mine area with <br />its long axis oriented north - northwest. For the Phase I area, the west pit slope should be sloped <br />at 1.6 H:1.0 V but the north, south, and east pit slopes can be sloped at 0.5 H:1.OV. The <br />reviewed plans indicate a west pit wall with an overall slope of 1.3H:1.0 V (40 -foot wide benches <br />with near vertical (0.06 H:1.OV) 30 -foot high bench faces). Based on our recommendations, <br />with a 30 -foot high near vertical bench face, the benches should be 48 feet wide in order to <br />provide an overall pit slope of 1.6 H:1.OV. <br />Along the west pit wall, bedding planes will dip into the cut slope and individual bench <br />faces with a near vertical orientation will undergo raveling and exhibit local instability. Shorter <br />bench heights of 15 to 20 feet and less steep bench faces (0. 5 H:1.0 V) may reduce the risk of <br />local instabilities. <br />7't S `.)r?UIh XVW, 1 10 lU�. I7 In X1 I .' �hI • \': tt'1�', I�l(.Cti;ll �.'.CU11'I <br />l.;,b I-a>, 303- ?, ? -y` 64 <br />hlu.in�:. 3U3.� Il ,i)O. i�rlain Fa;;, <br />