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Cross Gold Mine Permit No. M-1977-410 Technical Revision No. 7 Preliminary Adequacy Review <br /> <br />Grand Island Resources P.O. Box 3396 Nederland, CO 80466 <br /> <br />Ms. Amy Eschberger June 12, 2020 Page 4 <br />Schedule for Implementation After the cellular concrete placed in the subsidence pit cures for several weeks, GIR proposes to begin placing an additional 3 or 4 staggered layers of this material to partially fill in the saddle over the tunnel for long-term stability of the tunnel portal. Each lift is anticipated to be 4’ – 5’ thick placed in a set back or stairstep fashion. Individual lifts will be secured to the preceding lift with No. 8 rebar anchors on 1’ center-to-center spacing. 8” x 3” x 8’ long Douglas Fir lagging will be used as formwork and left in-place as facing. This entire mass will be anchored into the slope using grouted threadbar to serve as a slope retaining structure. Figure 6 presents a schematic illustration of this proposed design. The pervious cellular concrete serves to provide drainage behind the retaining wall with greatly reduced lateral earth pressure relative to granular fill due to its high cohesive strength and stiffness. The cellular concrete is stronger than granular fill and the low weight of the material reduces driving forces that could destabilize the slope. GIR proposes to constructed the individual lifts or layers in approximate 2-week intervals such that the entire stabilization effort can be completed by late August. Once construction has been completed, as-built information on the final slope geometry, cellular concrete and anchor placement will be used to provide stability analyses which will demonstrate that the slope meets the long-term stability requirements of MLRB policy. Should you have any additional questions or concerns please feel free to contact me at (516) 582-0833 or by email at Rmittasch@nedmining.com at your convenience. Sincerely, Grand Island Resources, Inc. Richard Mittasch VP of Operations Encl: Figure Attached: structure agreement with Boulder County for Caribou Road