2007-10-31_REVISION - M1977208 - Laserfiche WebLink

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Ms. Erica Crosby October 29, 2007 Page 4 • Set up a pumping yrtem in the southwest pond to move water from tbu pond auto water trucks used for road watering or other conramptive use, thereby reducing the impact of thu pond on C-Pit. • Once the 2008 imgation rearan commencer in April--May 2008, monitor the C-Pit higbwall far seepage, monitor the lined portion of the Canal, and monitor water fevelr an the routhwert pond. • CEMEX will continue to explore ways fa ure the C-Pit water in the pracerr that do nod ereade other adverse effects. • Propose alzernativer to water spraying as a dart rupprerrant in the C-Pit area far approval under the CPDHE Title VAirPermit. If there it no rign~cant reduction in observed inflow to C-Pit via the western highwafl during next summer's irrigation season, CEMEX will conduct further invertigationr to determine the raurce(r) of the inflow. There invertigationr may include addttional flaw gauging in the Canal at locatfonr fzrrther to the north than the gauging conducted by Brown and Caldwell during rummer 2007, and/ar installation of additional pie~ometers. If it is determined that seepage is significant along one or more portions of the approximately 1,900 foot reach Wert of C-Pit that is cut into bedrock, CEMEX will coordinate with Northern to determine the available options to line the canal to reduce seepage in this area. 3. The report indicates that leakage from the A-Pit water line is a possibility due to the past occurrence of the line breaking and the fact that the highwall in the vicinity of the A-Pit [sic] is wet Please pro~nde a plan to investigate the condition of the A-Pit water line and a mitigation plan in the event water is migrating into the C-Pit. CEMEX Response: Although it is Yrx[e that limited ana.r of ice formation have been observed in the part in the shaded portions of the northeast C-Pit highwall during the winter mantbr, CEMEX prttponen to defer tenting the A-Pit lone at thin time, pending the rerultr of the program outCrned above. Converrationr with the contractor who installed and malntainr the A-Pit Line indicate that bared on bin experience, thin type of litre rarefy has small leaky, but rather tends to petfarm as intended ar fail due to lice Grzakage, at which time r pairs are made. The line it a 6-inch HDPE line with tbernrally welded joinll. Water from this yrtem continuer to be ruccerrfully delivered to the cement plant spray tower without arty indication of lorrer. Part experience with this lone bar shown that any sign cant leaky quickly express themselves as wet, ponded arecrn on the surface, due to the shallow roily overlaying the bedrock along the pipeline route. In the event that the what we currently believe to be the major source of inflow to C-Pit (seepage from the Feeder Canal and Burt suppression water) es eliminated, and GPit water levels continue to Tire, CEMEX will conduct hydrontatlc tenting to confirm whether or not any leakage is detectable. Thin will entail pressurizing the line while closin8 the valz~ at the discharge end of the system near the spray tower. If the k'ne does not hold pressure, the rystem will be phut dawn, the line will be drained of all water and cleaned out by using compressed air, and the system will then be filled with pressurized heliumgas. Heliumgas detectors will be used to walk the alignment of the pipeline and determine the location of the leak or leaks, and the leaky will be rrpaired if they are located in an area that may be affecting C-Pit. 4. CEMEX is required to monitoring [sic] wildlife on the site in the vicinity of C-Pit. Please inform the Division if the wildlife monitoring and reporting plan will change as a result of the backEtlling of a majority of the pit and the recently installed net on the exposed water in the C-Pit. CEMEX Response: CEMEX will continue to monitor wildlife in the C-Pit vicinity. Thu is part of daffy operations monitoring program. No evidence of wildlife outride of pigeons hay been observed in the C- Draft Response to 10-5-07 Adequacy Review_TR-9_REV2