2019-03-19_REVISION - M1974086 (11)

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Figure C-3 Conceptual view of western slope profile, shows a bench height from 40-1 00 feet, but Detail A-East dipping slope information text, and the included Brierley report, states bench height will vary from 40-80 feet. Please edit for consistency as needed. There is also no description in the mining plan as to who is conducting the blasting of the basalt. Will this be blasting be done by the permittee%perator, or subcontracted to a licensed blasting contractor?I am inferring at this time, based on the reports provided, that the blasting work is being conducted by Buckley Powder Company. See the corrected Map C-3 for the bench height information. Blasting is conducted by a licensed contractor, not the operator. Buckley Powder Company is the current contractor. EXHIBIT G -Water Information(Rule6.4.7): DRMS has reviewed the Brierley hydrologic report provided in Appendix 2, and acknowledges that this operation is located in a somewhat unique geologic setting with respect to groundwater issues. However, a review of historic aerial photography shows an approximately 5.5 acre area of standing water in the bottom of the quarry that has existed at a relatively constant level since the fall of 2013. This would seem to indicate that either the pit began to intercept groundwater at that level and has equalized, or that precipitation collected in the pit has not been discharged into the natural drainage system within 72 hours as required by the State Engineer's Office(SEO). Please demonstrate to DRMS that groundwater has not been exposed in the bottom of the existing pit, and will not be encountered during mining as proposed. If groundwater has already been exposed in the pit bottom, Asphalt Paving will either need to backfill the area exposed to at least 2 feet above static water level, or achieve compliance with the SEO requirements for a well permit and substitute water supply plan until the pit passes the test for a sealed reservoir. If Asphalt Paving has already addressed this issue with the SEO please provide documentation. Exposure of groundwater in an unlined excavation will also have significant bonding implications. DRMS will be required to bond for backfilling the excavation to above static water level, or lining the excavation to meet the SEO standards for a sealed reservoir. As explained in the Brierley geotechnical and hydrological reports, the basalt formation of the quarry is seated within a shale boundary. This makes the site very useful for the purpose of water storage, as it is isolated from regional water flows. Such isolation also means that there is not likely to be an aquifer for the quarry to encounter and dewater. The operator's experience onsite supports this: stormwater must be handled through the permitted ponds and discharge system as it will not infiltrate through the basalt. A letter was provided to the State Engineer's Office requesting revised comments on February 28, 2019. The SEO has informed APC that it is reviewing this letter. A copy of the letter is included in this response for records. To further demonstrate the lack of groundwater interception, Asphalt Paving will perform a leakage test in conformance with the Colorado SEO 1999 Guidelines for Lining Criteria for Gravel Pits. This test will involve the complete pumping out of the current water pool in the bottom of the quarry, and then 90 days of monitoring for inflows. The applicant will provide the Division with the results of this test once it is complete. The applicant requests that the Ralston Quarry AM-04 2 Creg Ix ki and Associatm PIRA