2002-04-11_REVISION - M1977342 - Laserfiche WebLink

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Mc Allen C. Sorenson Henderson Mine, Permit No. M-77-342, Revision No. TR-8 Page 2 be taken by Henderson to ensure that the fill material does not contain any rocks or other materials that could potentially damage the liner. To avoid the immediate need to purchase or rent earthmoving equipment (i.e. rubber-tired earth mover or conveyor), Henderson intends to initially deposit sludge into the pond without placing any equipment on the pond liner. Our initial approach is [o move the sludge from the stockpile area with afront-end loader that will empty sludge into the pond without traveling over any lined areas. This will allow Henderson to use equipment already available at the site and provide us with additional flexibility to move and place the sludge as time and resources are available. Should we elect to use a conveyor system to move sludge, as described in the TR-8 application, we would not place the conveyor on any lined areas of the pond prior to placement of fill as previously described. Due to the steep and high slopes of the pond walls, the sludge will naturally flow into the pond by gravity. Should we need to further spread the sludge, we initially plan to move the sludge in the pond by casting water onto it by hose. We don't anticipate using large quantities of water to accomplish this, and if _ necessary, we would pump water from Pond 1.2 with an existing sump pump into our process water stream for tteatment. PLACEMENT OF GRAVEL AND COMPACTED FILL ON LINER The TR-8 application also describes the use of gravel and compacted fill on the liner in association with the placement of a permanent sump system. To prevent any damage to the liner during these activities, Henderson would use rounded gravel that does not contain angulaz pieces that might damage the liner. Additionally, any compaction activities would be performed with special caze [o avoid damaging the liner. As discussed in the TR-8 application, due to the size of the pond and the quantities of sludge [o be deposited, placement of the permanent sump system will not likely be necessary for several years. SLUDGE STOCKPILE BARRIER Sludge transported from the Urad impoundments, as described in the TR-8 application, would be stockpiled in a concrete secondary containment area located adjacent to Pond 1.2. This structure would serve to protect surrounding unlined areas and avoid the potential for stormwater contamination. This secondary containment area was used in the past as a loading azea for corrosive liquids when the pond was used as part of Henderson's water treatment process. We plan to conduct both the stockpiling and deposition of sludge into the pond concurrently to ensure that we do not exceed the capacity of this secondary containment area, and to avoid the need for long-term stockpiling of the sludge. We hope [o begin this project as soon as possible to maximize our use of the limited construction season at Henderson, and greatly appreciate your assistance with this matter. Please contact me at (303) 569-3221, extension 1287 if I can be of further assistance. Sinc~L T~~ucer~ Environmental Coordinator Henderson Mine cc: Joe Hatrick, Henderson Mine Anne Beierle, Henderson Mine