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configuration after all mining is completed will be that the entire area will resemble the <br />original topography with some minor variations. These minor variations, which will have • <br />no significant affect on the overall hydrology, are the Streeter Gulch mine fill, the Gulch <br />A mire fill, and the final area adjacent to Taylor Creek which will be lower than the <br />original ground. Drainage of the entire mine fill areas, mined area, and area ro be mined <br />has been designed to minimize erosion and to convey all drainage to three sedimentation ponds <br />prior to release of the drainage flow into the continuing natural flow channels. The areas <br />draining into these three sedimentation ponds are discussed in the following subsections. <br />Streeter Gulch Mine Area and Fill <br />This fill consists of the initial fill placed in Streeter Gulch at the commencement of <br />mining and the subsequent fill placed progressively in the mined area as the mining pro- <br />gressed in a southerly direction. All drainage from this fill is directed to the Streeter Gulch <br />ditch and thence to the Streeter Gulch sedimentation pond. This is accomplished by ditches <br />on the berms located at intervals of 100 feet in vertical height which are gradually sloped <br />in the direction of the Streeter Gulch ditch which collects the flow from the berm ditches <br />and runs on an alignment close to the premining Streeter Gulch until it empties into the • <br />Streeter Gulch sedimentation pond. Sections of the berm ditches are illustrated on Figure 6. <br />The area of the Streeter Gulch fill being drained to the Streeter Gulch i <br />sedimentation pond will increase gradually as the area is mined and the fill is placed. <br />Presently the area contributing to the Streeter Gulch runoff is considerably less than the <br />1,424 acres shown in Table 1 as the maximum area drained by the Streeter Gulch ditch, <br />as a portion of the undisturbed area is being drained to Prospect Gulch, a certain amount <br />of undisturbed area drains into the active mine, and the precipitation falling on the area <br />being mined runs into the lowest area of the mine where it either seeps into the ground, <br />evaporates, or in some cases is pumped out into one of the drainage ditches. This gradual <br />buildup of the drainage area Flowing into the Streeter Gulch sedimentation pond allows <br />time for reclamation of the land fill so that the fill placed in the early part of the operation <br />is well vegetated by the time new fill is added to the drainage area. Thus, at any one time <br />only a small percentage of the total fill is new fill that would be subject to erosion yielding <br />significant sediment in the event of a severe rainstorm. • <br />5 <br />