1988-04-11_PERMIT FILE - C1981008A (21)

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(approved by CMLRD) at several of the existing sedimentation ponds (001, 002, 004, 005, and 006) during 1987, discharge monitoring for compliance with the Nucla NPDES Permit (CO-0000213) has been altered for each site with regard to the monitoring point below each pond. The resultant change in monitoring points at Ponds 002, 004, 005, and 006 simply involves present and future monitoring for flow and quality at the spillway outlet (drop inlet pipe) constructed at each pond. However, because of requirements by CMLRD for continuous monitoring of flow at the 001 pond (NPDES 001), Peabody reestablished the 001 monitoring point just below the newly constructed spillway outlet shortly after construction activities were completed. The reestablished point for the NPDES 001 monitoring site consists of a sharp-crested 900v-notch weir continuously measured by a Steven's Type-F water level recorder. No changes were made in the frequency and parameters monitored during the 1987 water year at any of the modified monitoring points (NPDES 001, 002, 004, 005, and 006). Future monitoring will be consistent with the existing NPDES permit monitoring requirements (see Tab 7, Appendix 7-6). In addition, prior to any mining disturbance at Nucla East, Peabody will secure an amendment to NPDES Permit No. CO-0000213 for an additional NPDES site (007). Monitoring and reporting of data collected at this NPDES site will continue throughout mining and reclamation activities. All conditions and stipulations required in the NPDES permit will be adhered to during monitoring and reporting. Surface Water Monitoring Programs During and After Active Mining Operations. Surface water monitoring during and after mining at the Nucla and Nucla East mining areas will be essentially the same as the existing monitoring programs. As changes and revisions of the existing monitoring program become necessary, Peabody will contact the CMLRD and discuss any changes in the monitoring program. Then a minor permit revision to the existing permit will be written and submitted to the CMLRD. Surface Water Monitoring Site Numbering and Alpha Designation System Peabody stores nearly all of its surface water data on its mainframe computer data base. In order to accomplish this, each monitoring site is assigned a four digit numeric number and a two letter alpha prefix designation. In some instances, the four digit numeric number can be the same for two different sites, but the two letter alpha prefix keeps each site unique. Table 15-3 shows how the computer alpha numeric site identification system is organized. 15-5 Revised 04/11/88