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Pagej 2 <br />State Adequacy Review Response Letter.doc <br />Exhibit D - Mining Plan <br />Comment: The Applicant has stated the site will be mined in 2 separate phases. Please <br />commit to delineating the active phase with monuments or other markers. <br />Response: The applicant agrees to delineate the active phase as requested. Item (d) of <br />this exhibit has been updated accordingly. <br />Comment: The Applicant has stated the access road will be 24 feet wide. Please indicate if <br />the access road will be paved or if water conveyance structures will be installed. <br />The Division requests this information in order to calculate the financial <br />warranty estimate. <br />Response: The 24' wide access road will be gravel, not paved. The only water <br />conveyance structure associated with the access road is the culvert, which is <br />located within the prescribed right-of-way for CR 81 and is identified on the <br />Existing Conditions and Mining Plan Maps. <br />Comment: According to Exhibit D, the topsoil stockpiles will be vegetated if they are left in <br />place for more than 180 days. Please specify the seed mix to be used to stabilize <br />the topsoil stockpiles. Seed quantities shall be specified as pounds of pure live <br />seed per acre. <br />Response: The seed mix to be used to stabilize the topsoil stockpiles will be a dryland <br />pasture mix. Exhibit D has been revised to reflect this and refers to the <br />dryland pasture mix and quantities table found in Exhibit E (2)(d). The <br />topsoil stockpiles will be hydroseeded and hydromulched. <br />Comment: The Applicant has stated stormwater diversion ditches may be either a cut ditch <br />or a berm. Please specify which method will be used and provide the Division <br />with a typical cross section of the structures. This information is required in order <br />to calculate the financial warranty estimate. <br />Response: The method used to convey stormwater to the sediment ponds will be a <br />combination of cut-ditches in some areas and berms in other areas and will <br />be determined in the field as mining operations progress. The cut ditch will <br />be 1.5 feet deep with 3:1 sideslopcs. For purposes of the financial warranty <br />estimate it can be assumed that a cut ditch with these dimensions will be used <br />in all areas as this will allow for the most conservative estimate. <br />Comment: According to Exhibit D, stormwater will be routed into sediment ponds. Please <br />provide the Division with a typical cross section and design specifications of the <br />sediment ponds. In addition, please indicate the point in the mining process the <br />,sediment ponds will be constructed. <br />Response: A copy of the Erosion Control Plan is included. This plan calls out the <br />minimum volume, approximate length and width, top and bottom of pond <br />elevations, 3:1 sideslopcs, and riprap rundowns for each pond. Also, I have <br />provided a copy of the Drainage Letter and Calculations provided to Weld <br />County to support the design. The sediment ponds are to be constructed as <br />soon as practical once mining operations commence. Both mining phases <br />will progress from the east towards the west. The ponds will be constructed <br />as soon as enough material has been excavated to allow the ponds to be <br />constructed as designed and allow for safe operation of equipment in these <br />areas.