Laserfiche WebLink
MEMORANDUM <br />have a disadvantageous orientation and location then there could be a large scale slope instability <br />However field observations by Lyman Henn and by J A Cesare did not reveal any such joints Based <br />on current information there is no reason to believe that there would be a high risk for such events <br />As verification of these slope stability evaluations an Observational Approach will be used to develop <br />the quarry Using this approach a small area of the mine in the first phase and away from the limit of <br />mining will be excavated first and used to observe actual ground conditions and rock slope behavior <br />Providing that observed conditions are consistent with the basis of these slope stability evaluations and <br />that the rock slopes do not show unexpected behavior the mine will be developed to the maximum <br />extents as proposed in the mine plan Additionally with the upper portion of the mine at a more gentle <br />slope inclination than the lower portion of the mine a similar reassessment of the rock slope stability <br />can be made and appropriate changes to the rock slopes made when the mine is extended below <br />elevation 5800 <br />Soil Backfill Slopes <br />Soil will be placed on benches as part of mine reclamation This soil is expected to be overburden <br />removed from above mineable rock weathered rock and unsaleable rock and fines as a byproduct rock <br />processing It is further expected that this soil would receive a low to moderate degree of compaction <br />except for weathered and waste rock containing large particles which is impractical to compact These <br />soils are all granular with angular to subangular particles and no more than approximately 25 percent <br />fines material finer than the number 200 sieve <br />Soil slope stability calculations are based on a purely frictional analysis neglecting cohesion which is a <br />conservative assumption Soil friction angles were estimated from correlations based on soil type and <br />density A safety factor of 11 was chosen by Lyman Henn to be the design criteria Based on these <br />analyses it calculated that fill derived from overburden and unsaleable material cold be placed on slopes <br />of 175H to 1V or flatter and that weathered rock could be placed on slopes of 15H to 1V or flatter <br />With a high level of compaction and with laboratory testing to verify the soil strength it is expected that <br />any of these materials could be meet the design safety factor on a slope with an inclination of 1511 to <br />1V <br />Server0lcommonPROJECTS106052000 Parkdale Mine PlanR Records and CorrespondenceR08 Design CalculationsStability Memodoc