2018-06-12_PERMIT FILE - M1978332

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Colorado Rose Red, Inc. Page 3 Colorado Rose Red Granite Quarry M-1978-332 a. Please specify which structures will have a pre-blast survey conducted. For example, will the operator offer to conduct a pre-blast survey to any structure within a certain distance of the affected area? The blasting plan has been revised so it now addresses this question and it's sub parts. The tables were added to the revised Blasting Plan to provide the blasting contractor guidelines for the permit limits for this mine. We feel that with the properly designed charge weighs that the ground vibration limits and air overpressure limits proposed can be met at the property line. b. Please commit to conducting airblast monitoring to insure the airblast level is below the approved threshold. We have made air blast testing a part of the revised blasting plan. We prefer to use the term Air overpressure not Airblast. c. The applicant offers an airblast limit of 133 dB and a ground vibration limit of 1.0 inches per second. These limits are adequate for certain situation but not necessarily for others. The Division offers the following limits as a better defined and more flexible option: We are not sure how these tables will apply but feel that the company hired to do the blasting will be able to work with the proposed limits or Colorado Rose Red will file a revised blasting plan based on their expertise before blasting begins. i. Airblast based on the Lower Frequency Limit of the Measuring System: ii. Ground Vibration based on distance from nearest blast hole to the closest structure: It appears from this table that if the Scaled Distance (SD) factor of 55 is used it would cover all structures within 500 feet of blasting area. If the SD is increase then the potential impacts would be less. Again the company hired to do the blasting will be give this information and if needed the Blasting plan will be revised prior to any blasting taking place on the site. The plan includes measuring the partial velocity in 3 mutually perpendicular directions at each monitoring site. Rule 6.3.4 Exhibit D—Reclamation Plan 7. Based on your answer to Item#3 above, please revise your soil replacement plan. I revised pages 4, 5, 44 and page 50 to reflect t he numbers committed in the response to#3. 8. The applicants plan to close the mine openings using welded rebar cemented into place is not consistent with the standard adit closure practices. The Division recommends installing a grated adit closure with doors to allow the landowner access or a wire rope netting closure. Details regarding the specifications, materials required and the execution of these types of closures are available on the Division's website: hop : 1111nill"stag Document,, Cr,ir�raf"o�t)13r�{",?t)1pc�ifi�rtic�rr5.17df COLORADO ROSE RED ADEQUACY RESPONSE 01- June 8,2018(9.54am)