2019-06-17_REVISION - M2001038 (6)

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Albert Frei and Sons, Inc. Page 2 AFS.-Bennett Pit - M-2001-038 June 17, 2019 The treatment proposed consist of allowing the water to soak into the gravel layer that underlays the mine floor of the mine so it returns to the ground water table or the silt in the runoff will have settled enough to meet the discharge permit limits. Low spots on the mine floor collect the runoff so having designated basins is not needed. 4. Please describe the nature of the stratum immediately beneath the material to be mined. The entire permit area is underlain by a claystone or siltstone that is gray to dark gray with some orange staining (iron). The claystone is listed as very stiff to hard and plastic, while the siltstone is sandy with low plasticity. Both are impervious, but tend to weather and get softer when exposed. We expect mining to reach this underlying bedrock on the northern two-thirds of the mine. In the south area where the Potential Developed Water Storage area is shown the floor will be sandy gravel until/if the liner is installed, then the floor of the reservoir would be the bedrock. 5. It does not appear, AFS is proposing to use explosives at the site? Please confirm. If so, please addressed the requirements of Rule 6.4.3(I). No explosives will be used nor will blasting be done at this mine, the material is easily mined using conventual sand and gravel mining methods. I added this statement to Page 5. 6. Please clarify the type of processing that occurs at the site. At this time the only processing taking is the screening of the raw materials, no washing or crushing takes place. This material requires no treatment with chemicals or hazardous materials. Rule 6.4.5, Exhibit F—Reclamation Plan 7. Albert Frei and Sons (AFS) is proposing to continue to import inert fill into the site for use in backfilling the pit slopes and mine floor as stated on Page 6 of the reclamation plan as originally approved with Technical Revision No. 1 (TROI). TRO1 specified a phased approach to backfilling and estimated the void volume to be filled. It does not appear mining and reclamation will be conducted in a phased approach based on the revised mining and reclamation plan. Please describe any revision to the timing and duration of the inert fill operation. We took the phasing plan out because Albert Frei and Sons will mine the area faster then the original permit holder and staging is not conducive with their operating practices. The inert material will be piled, as it is delivered, along the final perimeters of the mine where the 3:1 slopes will be built. The plan is to follow mining on lope areas with placement of the inert material until enough is available to complete the final slope. Fill material will be accepted during the life of the mine until the volume needed to reclaim the slopes has been received or mining ends. Once sufficient fill, is in place along any section of slope it will be graded 3h to Iv, covered