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This Valley Leach Facility is a lined leach pad where an impermeable liner was placed in the old <br /> Squaw Gulch valley, which is then filled with crushed ore and allowed to leach to extract the <br /> gold in solution, which is then recovered in a lined pond at the plant at the toe of the facility. The <br /> crushed ore is placed in 100 feet tall lifts at a maximum angle of approximately 1 AH:LOV to <br /> 1.5H:LOV, followed by a horizontal bench of approximately 30 feet. The crushed ore is <br /> generally less than 3/4 inch in size although some larger sizes may exist in small quantities. <br /> Designs were completed by AMEC consultants in September of 2011 and approved by the <br /> DRMS. Design criteria can be seen below: <br /> 1.4 Design Criteria <br /> AMEC completed the engineering design for the VLF using the design criteria <br /> presented in the following paragraphs. <br /> Geometric design criteria for the VLF are presented in the following table, which <br /> includes a maximum ore depth over liner of 800 feet. <br /> Parameter Value <br /> Maximum ore depth over liner 800 feet <br /> Nominal ore angle of repose slope 1.41­1:1V <br /> Overall operational ore side slope against upsloping ground 1.61­1:1V <br /> Overall operational ore side slope against downsloping ground 2.51­1:1V <br /> Overall operational ore side slope above Squaw Gulch VLF PSSA 2.51-1:1V <br /> embankment <br /> Overall operation ore side slope above mill 2.01­1:1V <br /> Maximum lift height 100 feet <br /> The design was prepared and signed by Jay N. Janney-Moore, PE (CO 37571). The resultant <br /> Factors of Safety can be seen below. <br /> Minimum reclaimed slopes static factor of safety 1.5 <br /> Minimum reclaimed slopes pseudo-static factor of safety 1.1 <br /> Annual Inspections and Reports have been performed by Jay Moore, P.E., now of Newfields <br /> since 2015. During the Annual Inspections, Mr. Moore observes the overall stability of the <br /> embankment, including slopes, benches, foundation and internal solution ponds. He verifies the <br /> operation construction to ensure it is in accordance with the project design. He also evaluates the <br /> underdrain flow and water quality with respect to the leach facility containment and <br /> P <br /> erformance. <br /> Flyover topography was developed for each year since 2015 and changes were evaluated in <br /> Autodesk Civil 3D software for any changes that would require attention. Mr. Moore, P.E. <br /> 45 <br />