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Pinon Ridge Mining LLC <br /> 31161 Highway 90, PO Box 825 <br /> Nucla, Colorado 81424 <br /> July 23, 2019 RECEIVE® <br /> Mr. Lucas West, Environmental Protection Specialist Avg Q; to19 <br /> Colorado Division of Reclamation, Mining and Safety ��I <br /> 1313 Sherman Street, Room 215 Ali <br /> Denver, CO 80203 <br /> Re: Letter Report, Completion of Earthen Cover on Low-Grade Stockpile <br /> Sunday Mine, Permit No. M-1977-285, Addendum to Technical Revision 4 <br /> Dear Mr. West: <br /> Pinon Ridge Mining LLC (PRM) placed a 12 to 18-inch soil cover over the northern portion <br /> of the Sunday Mine Low-Grade Stockpile from July 8 to July 12, 2019. The cover was <br /> placed on those areas of the stockpile that had uranium concentrations greater than 500 <br /> parts per million (ppm) in accordance with the approved technical revision (TR). This <br /> report summarizes the earthwork that was completed and the field measurements that <br /> were implemented to verify that the cover was of adequate thickness and low in uranium <br /> concentrations. <br /> Several minor modifications were made to the TR-4 verification plan. A Global Positioning <br /> System (GPS) field device was utilized to establish the grid locations rather than using a <br /> tape measure. This allowed for preparing more accurate maps of the stockpile, the <br /> sampling grid, and the associated XRF measurement points. We were unable to extend <br /> the sampling grid on to the stockpile slopes due to their steepness. Instead, individual <br /> measurements were taken where there was safe access (typically near the top and base <br /> of the stockpile slopes). We also did not attempt to measure the cover thickness at each <br /> grid point, but rather used closely-spaced 12-inch high grade stakes within the grids to <br /> verify that a minimum of 12 inches of cover was being placed. Due to the coarseness of <br /> the ore and the limitations of the equipment, the cover thickness was usually in the 15 to <br /> 18-inch range. <br /> Pre-Construction Activities <br /> Prior to the start of construction, Mr. Kaiwen Wu, an independent contractor, located the <br /> area of the stockpile that had uranium concentrations greater than 500 ppm that was <br /> previously identified on Figures 6-1 and 6-2 of TR-4. Mr. Wu is an experienced uranium <br /> geologist with expertise in using X-ray fluorescence (XRF) and global positioning system <br /> (GPS) field instruments. He utilized an Olympus M Series Vanta XRF Analyzer for this <br /> task, which has a built-in GPS function that allows the collected data to be accurately <br /> transposed onto a site map. This negated the need to manually record measurements <br /> using alpha-numeric IDs. <br /> A 40-foot by 40-foot uniform grid was established on the top of the stockpile as shown on <br /> Figure 1 , Stockpile Grid Locations. Five random measurements were taken and averaged <br /> to determine if the grid was above or below the TR-4's 500 ppm limit for uranium <br /> 1 <br />