2019-07-09_REVISION - M2004044 (30)

Home Browse Search

of dewatering will be conducted in accordance with the CDPS discharge permit, which sets forth formal monitoring parameters including weekly visual monitoring for oil and grease. In accordance with the CDPS permit requirements, a Stormwater Management Plan (SWMP)will also be developed for this site. The SWMP identifies potential sources of pollution that may reasonably be expected to affect the quality of stormwater runoff from areas around the site;and describes the implementation practices to be used to reduce the pollutants in stormwater discharges associated with the facility. Dewatering water pumped from the South Mine Area will be discharged to the upstream end of the Brighton Return Ditch(See Exhibit C-4)near the west end of the mine limit. The water will flow directly into the South Platte River via the Brighton Return Ditch. The plan to discharge the dewatering water to the upstream end of the Brighton Return ditch will act as an area of recharge to the alluvial aquifer(a constant head boundary in ground water modeling terminology)and aid in the maintenance of the hydrologic balance. The constant head boundary will provide water to the aquifer to mitigate dewatering induced drawdown to wells. It has the collateral benefit to provide water the support the trees along the Brighton Return Ditch.Aggregate Industries will secure permission from the Brighton Ditch company to discharge the dewatering water to the ditch. Specific impacts to wells. A search of the State of Colorado Office of the Ste Engineer Database of wells on June 25 indicated four wells completed in the alluvial aquifer within 600 feet of the South Area. The potential impact to those wells and mitigation measure are described below. Bloom Wells The Bloom's have two wells completed in the alluvium(Permit Numbers 262132 and 2652132-A). They are classified for domestic use at 15 gallons per minute(gpm) and are located about 200 feet south of the Brighton Return Ditch. The discharge of the dewatering water to the Brighton Return Ditch will mitigate dewatering impacts to these well. Gary A. and Delores R. Baker The Baker well (Permit#101310)is located near the north west comer of the South Area about 100 feet from the mine limit. It is classified as stock watering only at 15 gpm. If this well is adversely impacted Al can provide the Bakers with livestock water. San Martin Caballero, LLC/Donald D. Stough The San Martin Caballero LLC well(Permit#12379 R-R)is located near the south east comer of the South Area about 100 feet from the mine limit. It is classified as irrigation for 18 acres at 350 gpm. If this well is impacted Al can drill a replacement well further from the South Area. (3) The Operator/Applicant shall provide an estimate of the project water requirements including flow rates and annual volumes for the development, mining and reclamation phases of the project Water use at the site is governed by the current well permit(Permit No. 81342-F)and the associated Substitute Water Supply Plan(SWSP)for the site. Water use will be at its highest during the mining phase of the project. Mining at the site will intercept groundwater tributary to the South Platte River. Consumptive uses of groundwater at the site include evaporation from groundwater exposed to the atmosphere,water retained in material hauled off sites, and water used for dust control. Aggregate Industries Tucson South Resource Permit#M-2004-044112 Permit Amendment Page G-2