2009-08-28_PERMIT FILE - M2009035 (3)

Home Browse Search

• Describe any improvements necessary on existing roads and the specifications to be used in the construction of new roads. New or improved roads must be included as part of the permitted acreage. Describe any associated drainage • and runoff conveyance structures to include sufficient information to evaluate structure sizing; RESPONSE: The access will need to be improved before mining operations begin. Mesa County will require the connection point of the access to 32.5 Road be paved. The pavement section will include 0.04 acres and be constructed with 4-inches of asphalt over 8-inches of Class 6, over 12-inches of Pit Run. The remaining portion of the road will be covered with 8-inch thick Class 6. The culvert crossing will be improved with a 60- inch reinforced concrete pipe. An outlet pipe will be installed for each of the settlement ponds. The settlement ponds will be pumped at 0.6 cubic feet per second. The total area for disturbance for both of the pipes is approximately 0.04 acres. All other existing roads are currently located on site. Clarified in section 6.4.4(a) • It is stated in the mine plan that "the mined areas behind the highwall using overburden from the next mined area and imported inert fill." Please explain why the areas behind the highwall will be backfilled. RESPONSE: Statement revised to clarify the use of overburden. Revised on Page 7 to state: "Removal of overburden and mining for sand and gravel at the highwall area will be required at a 3:1 slope. The mined areas along the perimeter of the reclamation ponds will be set to final grade and backfilled using overburden from the next mined area and imported inert fill, where necessary, to achieve final grades. As the backfill material is placed near final grade, the areas will be prepared for site reclamation." Overburden will also be stockpiled for use as 'fines' in roadbase and for final grading of the site. Stockpiles of overburden will require a maximum 3:1 slope to prevent slope failure. • Under the heading "Typical Sequence of Operations" it is stated that "the total volume of stockpiled topsoil is approximately 49,000 cubic yards." The conditions observed during the preoperational inspection appeared to have less topsoil than 49,000 cubic yards. Please clarify the actual amount of topsoil and overburden located at the site. • RESPONSE: Revised on Pg 8, this included both overburden and topsoil. The topsoil quantity is 24,000 cubic yards. Assuming the maximum thickness of 6" covers the site. 49,000 is the total amount of material to be removed including topsoil and overburden. • Per Rule 3.1.9, where it is necessary to remove overburden in order to mine the construction material, topsoil shall be removed and segregated from other spoil. Please clarify what methods will be used to segregate the topsoil form the overburden and where topsoil and overburden will be stored until it is used for reclamation. Also what methods will be used to stabilize the topsoil while it is stockpiled. RESPONSE: "Typical Sequences of Operations", part (2) revised to clarify that topsoil will be removed first and stored separately to insure separation of materials. • Under the heading "Typical Sequences of Operations", part (3) states that "pumps will discharge the groundwater into a settlement pond that will be located near the southwest corner of each of the respective mining areas. Please revise the mine plan map to clearly identify the location of the settling ponds and what the settling pond configuration will be. RESPONSE: Plans revised to show approximate pond locations. Section 6.4.4(c) • The mine plan also mentions a drainage swale that will be installed along the west boundary line. Please located the proposed swales on the revised mine plan map. RESPONSE: Swale references removed from mining plan section. Areas being mined will be pumped of ground water. The pumped water will be piped to the respective settlement pond. Section 6.4.4(c) • Please clarify the proposed maximum amount of disturbance at any one time. The statement provided on the mine plan does not give enough information to accurately calculate a reclamation bond estimate. • RESPONSE: Document revised to consistently show 4 acres. 336 main street • suite 203 • grand junction, colorado 81501 • 970-242-7540 phone • 970-255-1212 fax