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Response to CGS Review of May 2010 Technical Revision Pikeview Quarry ?M-1977-211 Continental Materials July 2010 Attn: Mr. Berhan K-effelew Division of Reclamation, Mining and Safety Department of Natural Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 Dear Mr. Keffelew, - Rl- r? RECEIVED A,'J"Uh 14 2010 ®ivigiQn of i elamat{Qn, Mining & Safety Castle Concrete/Continental Materials would like to respond to the observations and recommendations in the assessment of our May 2010 Technical Revision by the Colo ado Geological Survey. 1. A blast plan will be formulated before every blast that occurs. This is not unlike what Castle has done for the last 50 plus years it has been operating. No level greater than 0.5 ft./sec. PPV will be generated during any blasting as was a condition of the February 2010 Technical Revision. 2. For clarification, the response to items 2 and 3 are answered in reverse order. The fill that will be placed in the north end of Area H will be the decomposed granite from the layback above. This is the material that was originally planed to be used and our geotechnical and civil engineers are in agreement with the use of this product for the proposed purpose. The material will be condition and placed using accepted construction practices for compaction. In the TR we do not address placing fill in the rubblized area in the south end of the quarry as part of the TR. Tom Terry P.E., P.G., used 120 lbs per cubic foot, dry density, and a modified proctor of 92%, for his calculations in fortifying the toe. His feeling are this is more than enough and would be easily attainable in the field. Once the north end of Area H is backfilled there will be an area capable of acting as a staging area for the material that is removed from above. There is no intent on having work being performed above while personnel are working below. Conventional equipment would then- be used to pick up the material and move it to our processing site. 4. What CGS calls the northern block is actually below the middle peak and we agree it is unstable. Only after we have an opportunity to get to the top and do more evaluation will we be able to determine what will need to be removed. Our geotechnical consultants will assist in the determination. Monitoring of all prisms will continue throughout the process. 5. Through the investigative process on the north end of the quarry it is our intention to develop the methodology and best practices of how to reclaim the south end. This will be address in more detail in the amendment that will follow in the full scale mining and reclamation plan amendment.