Laserfiche WebLink
iii iiiiiiiiiiiuiii <br />STATE OF COLORADO <br />MINED LAND RECLAMATION DIVISION <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, CO 80203 <br />303 666-3567 <br />FA x: 303 832-8106 <br />DATE: September 8, 1992 <br />T0: <br />FROM: Mike <br />Cathy Long <br />Begej <br />~ ~'/~ <br />, <br /> (J J <br />Q~~ <br />cS~~ ~~2 <br />~~R~L <br />04 ~o~ <br />~~~~''8 <br />~ ra 76 ~ <br />Ray Ramer. <br />Governor <br />Michael B. Lonp, <br />Division Director <br />~~ <br />RE: Vacation of Notice of Violation 92-015, Twin Pines Mine, C-83-058 <br />This letter initiates a request for vacation of N.O.V. 92-015 from the staff. <br />This violation was written on July 16, 1992 for the operator's failure to <br />maintain ditches at the mine site in accordance with the approved designs. <br />Four ditches were cited in the N.O.V. <br />During the July 14, 1992 inspection, the Division utilized the operator's <br />Mine Site Plan (Drawing TP-3> to identify locations of ditches. The Division <br />also reviewed hydraulic calculations found on pages SOa through SOc in the <br />permit application. <br />During the inspection, the Division identified four ditches that had had areas <br />of sloughing and excessive erosion that, in the Division's initial estimation, <br />were severe enough to have compromised ditch design criteria. Additionally, <br />arrows representing surface water flow paths occasionally were placed on the <br />map in locations where ditches described in the hydraulic calculations should <br />have been. The violation was written on the strictest interpretation of the <br />drawing and narrative, i.e. on ditches not being maintained to <br />previously-approved designs, and ditches not constructed in approved locations. <br />Following the inspection, a review of the permit files in our office <br />determined that the operator had previously provided certain hydraulic <br />calculations during the last renewal (February 10, 1990) documenting the use <br />of ditches and an adjacent, infrequently-used access road as waterways for <br />large storm events. These calculations had not been incorporated into the <br />permit and the Division was not aware of the calculations during the <br />inspection. <br />The operator has subsequently submitted a Minor Revision with revised pages <br />clarifying the permit and making its map consistent with the calculations. <br />This revision reflects on-the-ground conditions during the inspection and <br />indicates that on-the-ground performance during a 70-year 24-hour storm event <br />was not compromised. <br />I recommend vacation of this violation. <br />CWBlern <br />4714E <br />