Laserfiche WebLink
Broken Arrow Investments, LLC Derr Pit, Adequacy Review Comment Responses, File No. M-2008-017 10117108 <br />-6- <br />18. The mining plan indicates that the pit will be mined at a 3H:1V slope. However, <br />the reclamation plan calls for backfilling the slope. Please clarify why the <br />slopes will need to be backfilled if the pit is mined leaving a 3HAV slopes. <br />Response: <br />Overburden and topsoil that is removed during the mining will be used to reclaim the <br />mining slopes and areas that are disturbed during the mining such as haul/access <br />roads and the recharge pond. Overburden will be placed in the areas such as <br />haul/roads and the recharge pond to bring the grade to the final reclaimed elevation. <br />The overburden may also be spread on the 3H:1 V mining slope to use the excess <br />overburden to exhaustion. This will be accomplished by using a dozer to spread the <br />overburden material to a depth of one foot or less across the entire mining slope thus <br />maintaining a 3H:1 V slope. The slope will be compacted as described in Exhibit E. <br />Topsoil will then be placed to finalize the grading such that seeding can occur. The <br />topsoil will be placed at all disturbed areas and on the mining slope to an elevation <br />matching the expected reservoir water level. Please refer to the revised Exhibit E. <br />19. The reclamation plan calls for replacing the topsoil to a depth of six inches. <br />The Division recommends replacing topsoil to a depth of twelve inches. The <br />affected area will be primarily surface water when reclamation is complete. <br />This will provide the operator with a sufficient amount of topsoil, so as to <br />replace it to a depth of twelve inches. Please commit to using twelve inches of <br />topsoil. <br />Response: <br />The applicant will commit to placing twelve inches of topsoil. Please refer to the <br />revised Exhibit E. <br />20. The applicant indicates that the topsoil stockpiles will be seeded if they sit <br />longer than one growing season. Please specify the seed mix to be used on <br />the topsoil stockpiles per Rule 6.4.5(f)(ii). <br />Response: <br />The seed mix for the stockpiles is different than the final reclamation seed. The seed <br />mix for the stockpiles is as follows: <br />Temporary Stockpile Seed Application Rate <br />(#PLS/acre) % in mix <br />Slender wheatgrass 2.8 #PLS/ac 25 <br />Smooth bromegrass 3.9 #PLS/ac 30 <br />Pubescent wheatgrass 4.2 #PLS/ac 30 <br />Sand dropseed 0.03 #PLS/ac 5 <br />Crested wheatgrass 0.6 #PLS/ac 10 <br />Totals 11.53 #PLS/ac 100 <br />* Application rate is for drilling the seed. If seed is to be broadcast, the application <br />rate will be doubled. <br />The seed mix was recommended by the local NRCS office in Greeley, Colorado. <br />Please refer to the revised Exhibit E and the attached letter from the NRCS. <br />N N 1400 W 122`d Avenue - Suite 120 • Westminster CO 80234 • Ph: 303-457-0735 • Fax: 303-920-0343