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RECEIVED <br /> ZZCC_MC_X JUL 0 3 2014 <br /> Division of Reclamation, <br /> Mining&Safety <br /> Michael Cunningham July 1, 2014 <br /> Environmental Protection Specialist <br /> Colorado Division of Reclamation, Mining and Safety <br /> 131 Sherman St, Room 215 <br /> Denver, CO 80203 <br /> RE: Response to DRMS Preliminary Adequacy Review for CEMEX Sandstone Quarry; DRMS File <br /> No. M-1977-361 (AM-01) <br /> Dear Mr. Cunningham, <br /> CEMEX has developed responses to each of the items raised in your May 20, 2014 Preliminary <br /> Adequacy Review letter on AM-01 Reclamation Permit Amendment Application for the CEMEX <br /> Sandstone Quarry. Also included below are response to the supplemental comments provided in the May <br /> 15, 2014 Review of the Stability Exhibit by TC Waits that was attached to the Preliminary Adequacy <br /> Review letter. DRMS comments are reiterated in italics followed by a response from CEMEX. <br /> Additionally, while the designs contained in this permit amendment application are intended as <br /> conceptual designs only, not for construction, we noticed some areas where the conceptual final highwall <br /> was not configured to be entirely realistic. To correct this and prevent any future concerns as to the final <br /> topography, some slight modifications were made to the north and south highwalls in the revised Figure <br /> E-2. The proposed topography is an approximation of the existing pit topography with projected highwall <br /> slopes of 0.5:1 (horizontal: vertical). This modified proposed topography includes a bench at the top of the <br /> highwall that ranges from 10 to 15-ft wide with a 10-ft high backslope that varies from 0.1:1 to 0.5:1. The <br /> highwall slope below the bench slopes to the pit floor at 0.5:1. Due to the nature of mining, the final <br /> highwall may contain variable slopes that are approximately 0.5:1, thus the proposed topography is <br /> conceptual and there may be subtle differences in the as-built highwall slope. These minor modifications <br /> have been evaluated by the engineers at Engineering Analytics who completed the Geotechnical Stability <br /> Exhibit and have been found to have no additional impact on the site stability. <br /> Several documents referenced in the responses below have been attached to this letter including: <br /> 1. Revised Figures <br /> a. Figure A-4—Revised <br /> b. Figure E-1 —Revised <br /> c. Figure E-2—Revised <br /> d. Figure E-3—Revised <br /> e. Figure E-4— Revised <br /> 2. Appendix C-1: CEMEX Sandstone Quarry Typical Blasting Report <br /> 3. Appendix D-1: CEMEX Sandstone Quarry SEDCAD Culvert Outlet Channel Design <br /> 4. Geotechnical Stability Responses from Engineering Analytics <br /> 6.3.3 Exhibit C -Mining Plan <br /> Comment 1: The Applicant has indicated that it will be necessary to import topsoil to achieve a suitable <br /> depth of topsoil over reclaimed areas. Please specify at what point during the life of the mine the topsoil <br /> will be imported. <br /> CEMEX Response 1: Topsoil will be imported at the time when it is needed. Some topsoil is already <br /> stockpiled on-site and some more will be excavated during continued mining. Once all mining and final <br /> grading is completed the required quantity of topsoil will be imported and spread directly. <br /> Page 1 of 4 <br />