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SUMMIT ENGINEERING COI ENGINEERS & LAND SURVEYORS <br /> Mail: P.O. Box 1897 Alamosa, CO 81101 P: 719-589-6147 E: summitengco@gmail.com <br /> Mining Plan <br /> This proposal for the Robins Rock Pit establishes three phases of development. <br /> Phase 1: Complete excavations in those areas within the existing pit boundary. <br /> Phase 2: Expand excavations to the West along the edge of mesa. <br /> Phase 3: Further expand operations northward into the mesa. <br /> The first phase of the Robins Rock Pit, as shown in the accompanying Mining Plan map <br /> in the previous exhibit, has already been stripped of"top soil," and mining excavations <br /> and deposit processing(s) are well underway. Materials being excavated undergo a <br /> cleaning process that will proceed as it has previously. All fine materials will be <br /> separated with a power screen, and this material will be added to the topsoil stockpile. <br /> The topsoil stockpile will be located in an area in the southeastern portion of the permit <br /> boundary near the location of the abandoned/filled irrigation pond as shown on the <br /> maps in the previous exhibit. Additionally, both the loading area and rock processing <br /> areas are located at the bottom of the hill in this area. Product will be moved from the <br /> loading area to the nearby Conejos County Road H via an existing 20-foot wide gravel <br /> road. No further improvements to this haul road are anticipated. Mining operations are <br /> estimated to process approximately 50,000 tons per year. <br /> Drilling operations in progress are based on a pattern of 3 feet by 5 feet drilled to a <br /> depth of approximately 18 feet. Drilling has resulted in a highwall along the north and <br /> west perimeter of the existing pit, so a barrier of large rocks has been placed along the <br /> perimeter to prevent livestock and human traffic from accidentally falling into the <br /> excavated area. This method will be used to protect any highwall areas that occur in the <br /> future as operations expand further. No highwalls over the height of 20-feet or longer <br /> than a length of 200-feet will be allowed to develop as mining operations continue. The <br /> maximum depth of mining is planned to be 40-feet along the west edge of the pit (50- <br /> feet or more from the permit boundary). Mining operations will focus on excavating the <br /> basaltic strata of the mesa that is part of the Hinsdale Formation (Pliocene and <br /> Miocene) as shown on the geologic map of the lower Conejos River Canyon Area <br /> authored by Lipman in 1975 and shown on the following pages. No drilling has been <br /> performed at this time, so the depth of the basaltic layer is unknown throughout the <br /> permitted area. However, based on the geologic map it is anticipated that the basalt <br /> layer will be underlaid by the Los Pino Formation consisting of"Mostly bedded <br /> conglomerates, sandstones, and mud-flow breccias" at approximately the base of the <br /> exposed bluff (8,090' above sea level), or between 20 to 40 feet below the top of the <br /> mesa within the proposed permit boundary. <br /> a) Mining in Phases 2 and 3 will commence in January, 2021 and should end by <br /> December, 2030. <br /> b) The operator commits to salvaging or importing fine materials from the Robins <br /> Gravel Pit (M-2002-014) for enough topsoil to replace 6 to 12 inches throughout <br /> Job # 1200710MP - C Pagel13of79 <br />