2022-10-26_HYDROLOGY - M2008082 - Laserfiche WebLink

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Ready Mix Concrete Substitute Water Supply Plan Page 2 of 9 October 26, 2022 • Stage 2 - Mining at Stage 2 was completed by the end of 2016. • Stage 3 - Mining at Stage 3 began in June 2017 and was completed in early 2018. Stage 3 was completely backfilled in the spring of 2019 with overburden from other stages. No remaining lagged depletions are associated with this stage. • Stage 3B - Brannan has identified mining reserves between Stage 3 and Stage 4. Brannan intends to mine this small area, however such mining will not occur during this plan period. This location is identified as Stage 3B on Figure 1. • Stage 4 - Mining at Stage 4 began in 2018 and was completed in spring of 2021. A slurry wall was constructed around Stage 4 and a 90-day leak test was approved on May 23, 2018. Brannan completed the final construction to convert Stage 4 into its intended and approved post-mining reservoir storage use in 2021, and on July 1, 2021 the structure was transferred to United Water. Under this SWSP Brannan will replace all remaining lagged depletions from past mining and dewatering at Stage 4. Brannan is no longer responsible for Stage 4, and any depletions associated with future use at Stage 4 are not included in this SWSP renewal request. • Stage 5 - A slurry wall was constructed in July 2020 for Stage 5. Mining at Stage 5 will occur during this plan period. • Stage 6 - Mining at Stage 6A was completed mid-2017. • Stage 6B - Mining at Stage 6B was completed in March of 2018. • Stage 6C/6D - Mining at Stage 6C/6D began in 2019 following the installation of the slurry wall. Mining at Stage 6C/6D will occur during this plan period. • Stage 7A - Mining at State 7A is anticipated to begin by the end of 2022, following the planned completion of a slurry wall in Stages 7A and 7B during the summer of 2022. In accordance with the letter dated April 30, 2010 (copy attached) from the Colorado Division of Reclamation, Mining, and Safety ("DRMS"), all sand and gravel mining operators must comply with the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the protection of water resources. The April 30, 2010 letter from DRMS requires that you provide information to DRMS to demonstrate you can replace long term injurious stream depletions that result from mining related exposure of groundwater. The DRMS letter identified four approaches to satisfy this requirement. In accordance with approach nos. 1 and 3, you have indicated that a bond has been obtained for the new Morton-Holton Lakes site that can cover the cost of lining, to prevent the exposure of groundwater. The current bond amount for the new Morton-Holton Lakes site is $4,150,000.00. Depletions Evaporation The projected depletions for Stages 1, 2, 5, 6A, 613, 6C/6D and 7A/7B result from evaporation, water used to wash the mined product, water lost in the mined product, dust control and water for reservoir construction at Stages 7A and 7B.