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��Raindy III,,,,,,,,l e Ind III' <br /> May D <br /> 2020 <br /> A site inspection was performed by the Colorado Division of Reclamation, Mining and Safety ("DRMS") <br /> on November 29, 2018. Several violations were found, and a corrective action was issued, for <br /> numerous reasons including the water onsite. DRMS requested a revised amendment application <br /> ("AM-1"), which was submitted by the Applicant in January 2019, in compliance with the first part of <br /> the corrective actions imposed by the Mined Land Reclamation Board. The new mining plan proposes <br /> a total of 17 mining phases, separated into two primary mining cells. Phases 1 - 12 are located in the <br /> North Mining Area and Phases 13-17 are located in the South Mining Area. There is also a revised plan <br /> for managing mine water and stormwater on site, which includes a series of sediment ponds, ditches <br /> and pipelines. <br /> The exposed water surface area was found to be significantly higher than that which was reported in <br /> the SWSP application. The SWSP application was based on a total exposed water surface of 4.79 acres <br /> during the mining operations. The post-mining total water surface area proposed in AM-1 is <br /> approximately 159.5 acres, from three slurry wall lined water storage reservoirs. <br /> The total surface area of the dewatering trenches and sediment ponds will not exceed 4.79 acres for <br /> the term of this SWSR The total maximum area of the exposed water surfaces has been used to <br /> calculate the evaporative losses for this plan. The evaporation value for this area has been obtained <br /> from paragraph A.i of Exhibit R of the decree in Case No. 02CW181, which is 4.11 feet/year. <br /> Therefore, the evaporative losses for the exposed water surface is 4.79 acres X 4.11 feet/year, or <br /> 19.69 acre-feet/year (Table 1, attached). <br /> Water losses in the mined material have been estimated to be 18.39 acre-feet, based on a projected <br /> 1,250,000 tons of mined material and a 2% moisture content. The moisture content is less than wet <br /> mining (4% loss) due to the fact that the pit is lined with no influx of groundwater. <br /> Water losses from dust control and aggregate washing will continue to be augmented under the decree <br /> in Case No. 12CW37 which is the decree for the well with WDID 6705373 (Permit no. 79629-F, WDID <br /> 6705373). <br /> The total calculated depletion for this plan is 38.08 acre-feet. <br /> Replacement <br /> The proposed source of replacement water is GP Aggregates' ownership of 200 common shares in the <br /> Lower Arkansas Water Management Association ("LAWMA"). The proposed allocation for a LAWMA <br /> common share in 2020 has not been set, but is assumed to be 75%. Forty-one LAWMA shares will be <br /> dedicated to this plan for the replacement of the lagged depletions. Accounting will be provided by <br /> GP Aggregates to LAWMA, which will make replacement deliveries to the Arkansas River using fully <br /> consumable water. <br /> Depletions to the Arkansas River were determined using the Integrated Decision Support Group's (IDS) <br /> Alluvial Water Accounting System ("AWAS") model and a stream depletion factor ("SDF") of 88 days. <br /> Although DWR now discourages the use of the SDF method, these depletions were calculated in <br /> previous plans using the SDF, and the methodology is maintained in this SWSP request. The total <br /> stream depletion that will occur during this plan year is 30.77 acre-feet. <br />