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6.4.4 Exhibit D -Mining Plan MINING METHODS All of the mining operation will be "dry" mined. Dewatering trenches will be dug around the perimeter of each mining cell and dewatered to Boulder Creek (Cells 3 and 4) or to recharge trenches (Cells 1, 2, 5 and 6). Stripping and mining will incorporate conventional aggregate mining methods, including use of scrapers and dozers to strip overburden, backhoes and scrapers to mine sand and gravel, and haul trucks to move material onsite. This operation will mine and reclaim concurrently. The permit area has been divided into 6 mining cells. The order of mining will generally follow the numeric cell sequence. EARTHMOVING Cell 1 The north 1/3 of Cell 1 will be stripped of overburden and placed in the western 250-300 ft of the existing pond left behind from previous mining activities (M- 1979-120). Enough overburden will be left behind to backfill adjacent to oil and gas structures. As gravel extraction progresses, concurrent backfilling adjacent to oil and gas structures will occur no later than two weeks following excavation - as indicated in Exhibit C-2 -Mining Plan Map. Overburden from the south two-thirds of Cell 1 will be stripped and placed into the northeast corner of Cell 1. Following gravel extraction from the lower two- thirds of Cell 1, mining will begin in Cell 2 Cell 2 Overburden stripping will begin in the northern area of Cell 2 and stockpile approximately 100,000 yd3 immediately to the south of the excavation. Mining will proceed by mining the backfill areas prior to mining the lake areas. (See Exhibit F -Reclamation Plan Map.) This mining sequence allows for concurrent reclamation and a single movement of overburden wherever possible. Cell 3 Prior to mining west of Boulder Creek, a low water crossing will be constructed to allow haul trucks to access Cells 3, 5 and 6, per the US Army Corps of Engineers Section 404 Nationwide Permit No. 14 authorization. Additionally, once an agreement has been reached with the Plumb and Dailey Ditch Company or the DMG has approved a geotechnical study relative to isolating the ditch from pit dewatering, a hydraulic barrier trench wiA be constructed as shown in Exhibit C-2 -Mine Plan Map Sheet 1 for the purpose of hydraulically isolating the Plumb & Dailey Ditch from dewatering operations. Hydraulic Barrier Trench Construction The hydraulic barrier trench is to be constructed during the non-irrigation season when the ditch does not typically run (November-March). The plan and detail for the trench are shown in Exhibit C-2 -Mine Plan Map Sheet 1. Construction of the hydraulic barrier trench is to be completed as follows: Turnpike Mining Resource M-2004-AM-1 Regular 112 application