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<br />SUBNISTAL TO <br />NINED LAND RECLANATION DIVISION <br />SUNMARY OF <br />POND ENBANRNENT DESIGN <br />AT <br />ALMA PLACER NINE <br />• <br />• <br />By <br />Richard Urbanowski <br />Attached is a summary of activities that have led to the present d sign of the <br />berm that will service the dam for the recirculating pond waters o the Alma <br />Placer Nine project. This summary addresses the major topics of t e design <br />information previously supplied to your offices. We have also enc osed an <br />engineering plan sheet which reiterates the design and layout of tie berm. <br />HISTORY <br />The historic basis of the berm was an embankment used by previous ins owners. <br />During cleanup of the mine area in preparation for the new operati n, <br />sediments from the pond bottom were pushed onto the historic berm o enlarge <br />the berm. ibis created a loose, uncompacted embankment with excel ively steep <br />slopes. As part of the reactivation of this mine project, the bar was <br />modified to Dring it to current engineering standards. <br />The recent, loose fill and portions of the historic embankment war excavated <br />using bulldozers. Soil compaction tests were then run on the rams ning <br />historic berm, which was found to be densely compacted in excess o 95X. The <br />old berm was utilized as the basis for the construction of the new berm <br />configuration. On site materiels, consisting of portions of the o d berm and <br />pond sediments, were placed in twelve inch loose layers and compec ed with <br />four to six passes of a vibrating sheep's foot roller. Soil comps tion tests <br />were conducted on a daily Danis to assure adequate compaction wen thieved. <br />She resulting embankment is a sound, stable embankment. <br />ffiANRl~i SLOPE DESIGI <br />The basic design of the berm was completed according to guidelines contained <br />in the Bureau of Reclamation publication "Design of Smell Dams". he final <br />embankment has a maximum height of approximately 19 feet from cent r line to <br />crest. The crest is approximately 15 feet wide and has small cart en "berms" <br />to serve as safety guardrails per Nine Safety and Health Administr tion (NSHA) <br />standards. The side elopes of the embankment ere 3 horizontal to vertical <br />in accordance with conservative recommendations from "Design of Sm 11 Dams". <br />The stability analysis xas run on the embankment configuration aft r soils <br />analyses had provided basic onsite date. Factors of safety of thi data <br />condition exceeded 3.1 when no cohesion was assumed for the soils, and over <br />7.5 when reasonable levels of cohesion were assumed. <br />- 1 - <br />