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Exhibit D Skull Creek Sand Project
<br /> Mining & Backfill Sequence
<br /> Prior to mining, all recoverable soils within the affected area will first be salvaged (between 2"-
<br /> 6") and stored in windrow stockpiles surrounding the various operational areas as depicted on
<br /> Map D-3. Mining will then commence by excavation of the exposed Dakota outcrop within Pit
<br /> E-1. Once the outcrop has been removed, alternating blocks of overburden and Dakota
<br /> Sandstone will be excavated until the pit bottom is reached. Access to the pit bottom will be
<br /> accomplished by temporary ramps built into the progressing pit highwall to the west.
<br /> Overburden spoil from Pit E-1 will be hauled out of the pit and placed on the SPRS for eventual
<br /> rehandle and backfill into the final pit void of Pit E-5. Following the completion of Pit E-1,
<br /> concurrent in-pit backfill will be utilized to avoid ex-pit haulage and to expedite reclamation.
<br /> Once concurrent backfill has begun, each successive pit will be mined from East to West in the
<br /> same manner with the overburden being placed in the previously mined pits up to the designed
<br /> final reclamation topography (See Exhibit E). When mining of Pit E-5 is complete, the SPRS will
<br /> be fully re-excavated and hauled back to the pit for final reclamation.
<br /> Map D-1 and Table D-2 below also depict the approximate timing and production for full
<br /> excavation of pits E-1 to E-5. This timing assumes a first year at half capacity and a second year
<br /> at full production.
<br /> Table D-2. Quarterly Production Forecast
<br /> Recoverable
<br /> Plan Sand Plan Sand Overburden Komatsu Strip Ratio(CY OB/
<br /> Year Quarter Months Sand @ 80% (tons) (CY) (CY) 650 OB(CY) tons Sand)
<br /> (tons)
<br /> 1 1 Jan-Mar 138,928 173,660 93,896 383,867 383,867 2.2: 1
<br /> 11 2 Apr-Jun 138,919 1 173,648 1 93,889 383,842 1 383,842 1 2.2:1
<br /> 11 3 Jul -Sep 139,074 173,843 93,995 389,011 389,011 2.2:1
<br /> 11 4 Oct- Dec 129,157 161,446 87,292 395,711 395,711 2.5:1
<br /> Subtotal 546,078 682,597 369,071 1,552,431 1,552,431 2.3:1
<br /> 2 1 Jan- Mar 225,465 281,831 152,382 787,379 787,379 2.8:1
<br /> 2 2 Apr-Jun 173,505 216,881 117,265 838,210 838,210 3.9:1
<br /> 2 3 Jul -Sep 297,873 372,342 201,320 764,691 764,691 2.1:1
<br /> 21 4 Oct- Dec 256,039 320,049 173,046 620,651 620,651 1.9: 1
<br /> Subtotal 952,8821 1,191,1021 644,013 1 3,010,931 3,010,931 2.5:1
<br /> Grand Total 1,498,959 1,873,699 1 1,013,084 1 4,563,362 4,563,362 2.4:1
<br /> Product Streams
<br /> Dakota Sandstone is the primary and only expected extracted commodity, which will be mined
<br /> and shipped to a processing facility for comminution and sizing for eventual use as a frac-sand
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<br /> 11/1/2019
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