2010-07-27_PERMIT FILE - M2010019 (4)

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As stated in the Exhibit D Mining Plan submitted by the Applicant, Runoff will be collected and directed to detention ponds to control and minimize sediments with ultimate discharge across the access road onto lands of the owner of the pit." Also, as stated in Exhibit G Water Information submitted by the Applicant "The short term surface water change will be an increase in sediment and runoff, as a result of the temporary removal of ground cover during the mining phase. To compensate for this change, the bottom of the mined area will be graded slightly downward to the northwest corner. A sediment retention pond will be constructed at this point, with any pond discharge entering an existing nearby culvert under the county road. No pollutants will be discharged from the pond". The location of the detention pond is shown on the Exhibit C Mining Plan Map in the southeast corner of the permit area. The topography shows that overall drainage of the area will be southeasterly and it is the opinion of Division staff that this will be a suitable location for construction of a detention pond for sediment retention. The Applicant has committed to submittal of a Stormwater Management plan for the site in accordance with the requirements of CDPHE. Discharge from the detention pond will be controlled to prevent sediment from leaving the site. Reynolds Engineering conducted a hydrologic analysis of the site and determined that a 100 year rain storm event at the site could produce up to approximately 3.72 acre-feet of water, and that spring runoff could produce up to approximately 5.7 acre-feet of water. The analysis specified that, based on topography, a detention pond should be located in the southeast portion of the permit area. DRMS will require a detention pond minimally sized to accommodate a 25 year/24 hour rainfall event be constructed in the southeast portion of the site. The Division has determined that the applicant has satisfied the requirements of Rule 6.4.7(c) regarding stormwater protection and control. 2. Exhibit M - Other Permits and Licenses Construction Materials Rule 6.4.13 - A statement identifying which of the following permits, licenses and approvals the Operator/Applicant holds or will be seeking in order to conduct the proposed mining and reclamation operations a) "The Applicant has not obtained a CDPHE storm water discharge permit." Division of Reclamation Mining and Safety (DRMS) Response: A CDPS General Permit Stormwater Discharges Associated with Sand and Gravel Mining and Processing (And Other Nonmetallic Minerals Except Fuel) Authorization to Discharge Under the Colorado Discharge Permit System (Permit No. COR-340000) was issued August 31, 2007 by the Page 3 of 7