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r <br />1 JUN. -21' 95 (IYEU( 15 13 BMGC TEL 303 721 6813 p <br />~~ <br />small amounts of water as the adjacent tailings consolidate. <br />1 As stated in BMRZ's November 30, 1993 letter to the <br />Division, BMRI does not believe that the in-tailings <br />piezometers will provide meaningful data #or the <br />1 construction of the second raise. The piezometers will not <br />determine the location or thickness of a potentially water <br />bearing zone. The piezometers will provide no data on the <br />density, undrained shear strength or steady-state strength <br />1 of the water bearing layers which can be incorporated into a <br />stability analysis of the second raise. <br /> Stipulation No. 2 stated: <br /> "The operator will install markers to delineate the <br />1 set-back required between the tailings embankment and <br /> the free water pond. The markers must be clearly <br />1 visible and adequate to allow straight forward <br />verification in the field that the required set-back is <br /> maintained.^ <br /> HM1tI's letter dated November 30, 2993 to the Division <br />1 addressed the issue of establishing a setback for the water <br /> edge of the lower'pond from the main embankment such that <br /> the run-off from the 100-year, 2~F-hour storm event would be <br />1 held within the tailings facility but not in direct contact <br /> with the upstream face of the main embankment. Based on the <br /> surveyed average beach slope and the total inflow to the <br /> area from the storm event as estimated through standard Soil <br />1 Conservation Service methods, a conservative water pool <br /> setback from the main embankment of 250 feet will more than <br /> hold the event and the associated run-off. <br />1 . In early February, setback markers were surveyed to location <br /> and staked at 250 feet upstream of the main embankment. <br />1 <br /> The terms and conditions of the TR-16 approval have been <br /> fully completed. <br />1 If you have any questions, please call. <br /> Sincerely, <br />1 ,~a„~a s ~~t- <br />1 Alana L. Scott <br />Technical Superintendent <br /> cc: Anne Baldrige <br /> Dan Robertson <br />1 Sally Hayes <br />1 <br /> <br />1 <br />046 <br />