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History <br />• The landslide above Pond 012 was detected on the afternoon of March 6, 2000 during the <br />CDMC Inspection of the Yoas[ Mine. The slide must have occurred during [he previous <br />weekend, because the pond was inspected on Wednesday, March 1 by Michael Altavilla, SCC <br />Engineering Manager, Jay James and Tom Leidich, both from Montgomery Watson (MW1. A crack <br />ran from [he water level at Pond 012 in the northwest side of the pond, up along the slope <br />in a northeast direction to a section of [he Haul Road O berm and ditch. Two separate <br />areas of the fill material comprising the road berm slope had slumped to the south. <br />Jay James and Tom Leidich were contacted that evening following the Inspection to come out <br />and investigate the failure. That way SCC would be able to develop some recort¢nendations <br />co minrmize any additional slope deformation. Jay James and John Pellicer IMWI met with <br />Mike Altavilla (SCC) and Mike Boulay ICDMGI, on the 7`". A memo from John Pellicer to SCC <br />is included in Addendum 13-12B-A discussing the prelimrnary investigation. <br />In the Division's March 10, 2000 letter to SCC, the Division requested the following three <br />items as a result of the landslide that occurred in the vicinity of Pond 012: <br />• 1. Submit the results of monitoring and geo[echnical analyses that had been conducted to <br />date, and keep the Division informed on any changing conditions at the site of the <br />slide. <br />2. Submit the As-Built Certification for Pond 012. <br />3. Submit a technical revision for restoration of the slope above Pond 012 supported by a <br />geo[echnical analysis and stability analysis. <br />Item number 1 was addressed in the March 14, 2000 letter from SCC to COMG. This letter is <br />contained in Addendum 13-12B-B. Technical Revision No. 12 was submitted to CDMG on March <br />12, 2000 and subsequently approved on May 3, 2000. TR-12 provided the As-Built reports <br />and certification for Pond 012 and resolved item number 2. This attachment addresses item <br />number 3 and provides [he remaining information [o satisfy the Division's request. <br /> Following completion of the snowmelt runoff and the drying out of the ground conditions in <br /> the slide area another srte visit was conducted by SCC/MW personnel. This site visr[ on <br />• May 5 produced the S[abrliz a[ion of Pond 012 Slide Memo, which is i n Addendum 13-12B-C. <br /> This letter presented plans and methodologies to analyze and design s tabilization measures <br /> for the failed slope. Based on the methods pcesented, SCC chose the slope flattening <br /> option. <br /> 13-128-1 Revised 06/01 <br />