Laserfiche WebLink
drainage from this area with mine water discharge or any other surface <br />drainage. <br />Dorchester's request for a small area exemption for Substation No. 2 and <br />associated facilities was formally approved by the CMLRD on September 22, <br />1981. A copy of the original letter of approval is contained in Appendix <br />B. CMLRD Letters of Approval for Small Area Exemptions. <br />Due to the limited size of the disturbed area, and lack of a distinct <br />drainage basin, detailed surface runoff and sediment yield calculations <br />are not justified. <br />MINE DEWATERING SYSTEM <br />On November 30. 1982, Dorchester requested a Smali Area Exemption for a <br />mine dewatering line buried in the northern portion of the lease area as <br />shown on the Drainage and Sediment Control Map. (Map 20). Runoff and <br />subsequent erosion from the area disturbed by waterline installation is <br />negligible due to the small area of disturbance (less than 0.5 acres), and <br />the location of the waterline on a plateau area several hundred feet from <br />existing surface drainages. The pipeline disturbance was reclaimed and <br />reseeded in 1982, resulting in establishment of effective vegetative <br />cover. A short light-use road provides access for waterline inspection <br />and monitoring of the discharge flow meter. The access road was graveled <br />in 1991 to minimize erosion and limit surface runoff. <br />With reclamation of the pipeline disturbance and effective drainage <br />control on the access road. there is no need for supplemental drainage and <br />sediment control in this area. Runoff and erosion characteristics are <br />essentially the same as for adjacent undisturbed lands. The dewatering <br />line was properly designed and installed to prevent damage or leakage and <br />regular inspections insure the continued integrity of the line. <br />Therefore, there is no mixing of surface drainage and mine water <br />discharge. <br />• Dorchester's original request for a Small Area Exemption was formally <br />approved by CMLRD on December 10. 1982. A copy of the original letter of <br />REVTRI5.REV <br />1711519311em 200R Revised November 1993 <br />