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eme <br /> Continental Materials Corporation <br /> Transit Mix Concrete Co. 440 S. LaSalle St. Suite 3100 <br /> Chicago IL 60605 <br /> January 6,2016 <br /> Mr.Tim Cazier <br /> Colorado Division of Reclamation, Mining and Safety <br /> 1313 Sherman,Suite 215 <br /> Denver, CO 80203 <br /> Subject: Wash Fines Pond Embankment Technical Revision ground water clarification <br /> information for Transit Mix Concrete Company on behalf of Continental Materials <br /> Corporation, Daniels Sand Pit#2 M-1973-007SG <br /> This document is intended to answer questions from Mr.Tim Cazier and Mr. Wally Erickson that were <br /> sent in a letter dated November 23, 2016 and post Daniels Pit#2 site inspection on December 7, 2016. <br /> Responses to your comments and questions are provided by Chris Sanchez at Bishop-Brogden <br /> Associates, Inc(BBA).These refer to the possible interaction of the proposed settling pond with the <br /> ground water system, particularly the existing ground water contamination plume managed by Schlage. <br /> This document is in support of the Daniels Sand Pit#2 Wash Fines Technical Revision. <br /> Existing Conditions <br /> Daniels Sand Pit#2 does not intercept ground water. There are alluvial water wells that supply water to <br /> the existing wash plants and for use in dust suppression. In addition to this, water is diverted from the <br /> Fountain Mutual Ditch into an augmentation pond which has been in use for quite some time. Water <br /> level drawdowns are seen in the areas of the wells and water mounding is present in the areas of the <br /> augmentation and existing wash fines ponds. <br /> In the area of the proposed Wash Fines Pond,the ground water level is currently measured at 7 feet <br /> below existing grade on the north end and grows to 20 feet below grade to the south.Transit Mix <br /> Concrete Company(TMCC) on behalf of Continental Materials Corporation (CIVIC)will commit to only <br /> excavating as much borrow material from the floor of the proposed pond as necessary to complete the <br /> construction of the necessary embankment.This is estimated to be as little as taking a three foot deep <br /> cut across the entire floor of the proposed pond location.At any time the borrow excavation will <br /> maintain a minimum of two feet of unsaturated material above the water table. <br /> More details regarding the existing conditions at Daniels Sand Pit#2 are found in Appendix A:Ground <br /> Water Memorandum Prepared By Bishop-Brogden Associates, Inc. <br /> Water Level Change Estimates <br /> BBA completed analytical calculations to estimate the amount of water level mounding that may occur <br /> beneath the proposed Wash Fines Pond. It is anticipated that there will be some increase in water level <br /> mounding and will be in the range between 11 and 16 feet at the edge of the proposed pond and range <br />