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~i <br />-19- <br /> <br />The sediment control system has been reviewed by the Division. Designs for <br />the sediment control system are found on pages 2.05-12 through 2.05-18 of <br />Volume 1 and in Exhibit 16 of Volume 2 of the permit application. <br />Surface runoff will be controlled on approximately 17 of the total 38 acres of <br />refuse material along the north bank of the Middle Fork of the Purgatoire <br />River. The remaining areas covered by refuse piles are not within the permit <br />area and contain refuse piles constructed prior to the enactment of the <br />Colorado Surface Coal Mining Reclamation Act. The refuse piles are not active <br />and will not become active under the remaining life of mine at the Allen <br />Mine. Therefore, they are not regulated under the permanent program. <br />Surface runoff from most of the disturbed area is contained by four sediment <br />ponds. These ponds are capable of containing the runoff generated by a 10 <br />year, 24 hour storm event and are designed to contain 0.1 acre-feet of <br />sediment per acre of drainage area. The ponds are all equipped with an <br />emergency spillway capable of passing the peak runoff from a 25 year, 24 hour <br />storm event. The princi al spillwa is ated but th _gate will be_o.p.eDeSLa. <br />calculated amount to aL~ nr automatic d~atEringJiltt~a_deten~i.nn_t~me~i <br />24 hours. A series of ditches route disturbed drainage water to the sediment <br />ponds and undisturbed drainage around the disturbed area to the Purgatoire <br />River. These ditches are capable of handling the peak flow from a 10 year, 24 <br />hour storm event. <br />The application does not contain a statement, certified by a registered <br />professional engineer, that the sediment ponds have been constructed as <br />designed. Therefore, the following stipulation is necessary to make a finding <br />of compliance with Rule 4.05.6(7): <br />Stipulation No. 3: <br />WITHIN 30 DAYS OF PERMIT ISSUANCE, THE PERMITTEE MUST SUBMIT A STATEMENT <br />CERTIFIED BY A REGISTERED PROFESSIONAL ENGINEER THAT THE FOUR SEDIMENT <br />PONDS HAVE BEEN CONSTRUCTED AS DESIGNED. <br />The mine area west of the railroad round house and some portions of the refuse <br />piles do not employ sediment ponds to control siltation. The applicant has <br />not described what activities will occur in the west area over the next five <br />years or what sediment control measures are used or planned to be used for <br />both areas. The applicant requested and received a variance from sediment <br />control for the West area during 1980. However, since this information is not <br />included in the permit application, the following stipulation is necessary to <br />find the proposed operation in compliance with Rules 4.05.2 through 4.05.6: <br />Stipulation No. 4: <br />WITHIN 60 DAYS OF PERMIT ISSUANCE, THE PERMITTEE MUST SUBMIT A PLAN FOR <br />SEDIMENT CONTROL FOR THE WEST AREA. IF THIS PLAN DOES NOT INCLUDE THE <br />USE OF SEDIMENT PONDS, A REQUEST MUST BE MADE FOR ALTERNATIVE SEDIMENT <br />CONTROL MEASURES. THE REQUEST MUST JUSTIFY WHY SEDIMENT PONDS ARE NOT <br />