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ENVIRONMENT, INC. PAGE 3 <br /> DECEMBER 24, 2014 <br /> Response to Mr. Peter Hays Memo dated 12/18/2014 <br /> 1. In response to Item#10, the Applicant stated electronic copies of the Geo Studio files <br /> for the Deere &Ault slope stability analysis data are available upon request. Please <br /> submit hard copies of the stability analysis data so the information is part of the public <br /> record and the Division can duplicate the Deere & Ault models accurately. <br /> Attached are the items you requested. They have been updated to correct the problems with the <br /> cross-sections you note below. <br /> 2. The Deere &Ault stability analysis was based on generalized conditions and produced <br /> a factor of safety less than 1.3 in three of the five models (cross-sections B-B, C-C and <br /> E-E). Since the factor of safety was less than 1.3, the Division will require the <br /> Applicant to obtain structure agreements for all property, including easement holders, <br /> and structure owners within two hundred feet of the affected land. Alternatively, the <br /> Applicant may revise the model perimeters to increase the factor of safety to 1.3 or <br /> greater. Please note the Division has not verified the 1.3 factor of safety for cross- <br /> section D-D. <br /> Deere& Ault updated and corrected cross-sections 8-B, C-C and D-D and reran the models using <br /> the revised data. Attached are copies of the revised Figures 2, 3 & 4 showing the changes needed <br /> to increase the safety factor to 1.3. In general the mine highwall was changed from a 0.5:1 (H:V)to <br /> a 1.5:1 (H:V)on the upper section. <br /> 3. Please review cross-sections C-C and D-D on Deere &Ault Figure 6 and Map Exhibit <br /> C-1 Mining Plan Map. It appears the offset distance and Monaco Street loading was <br /> illustrated on the incorrect cross-section. The stability analysis models, Deere & Ault <br /> Figures 1 and 2, appear to represent the cross-sections accurately. <br /> Thank you for catching this. Deere and Ault has corrected Sections C and D on Figures 6 and 7 and <br /> revised Figures 3 and 4. 'I have revised the cross-sections on Map Exhibit C-1 - Mining Plan Map to <br /> match. <br /> 4. Please update the stability analysis cross-section D-D model to include surcharge load <br /> from the proposed haul road. <br /> Cross-section D-D has been revised to show the haul road and the revised safety berm. The mining <br /> setback was increase to 45 feet to meet the 1.3 safety factor requirement. <br /> 5. Please update the stability analysis cross-section B-B model to include surcharge load <br /> from 88th Avenue. <br /> We have updated cross section B-B showing the relationship of the mined slope to 88th Ave. The <br /> pavement is approximately 45 feet from the property mine or 65 feet from the dig line and is <br /> approximately 17 feet lower than the existing grade of the mine and therefore does not affect the <br /> slope stability. <br />