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The proposed mining plan will limit the erosion and sedimentation on-site and off-site in the <br />following manner. First, CMI will limit the total disturbance to less than 60 acres through <br />concurrent reclamation. Second, the majority ofthe disturbance during mining will be confined <br />to the actual mining pits themselves. Once CMI has mined below the current ground elevation, <br />stormwater in the pit will be unable to access the mesa edge or the minor drainageways. CMI <br />will not mine within 100 feet of the mesa edge and the minor drainageways. <br />i Erosion control will be a very important part of reclamation work throughout the life of the <br />operation, affecting water quality, soil quality, vegetation, grading, and slope stability. The <br />following is a list of reclamation and erosion control techniques available for use. <br />Contour ridging. This technique employs a plow or disk to create a series of trenches running <br />perpendiculaz to the slope. The trenches reduce slope length by catching and holding water, thus <br />allowing it to percolate into the slope. Spacing between the trenches and trench depth depends <br />on the form of equipment used. Wind erosion can also be reduced by contour plowing. The <br />' moisture holding capabilities of the ridging also encourages seed germination. <br />Diversion terrace. A diversion terrace is a channel with a supporting rise (or berm) on the lower <br />' side constructed across the slope. It is used to reduce slope lengths, break up concentrations of <br />runoff, and move water to stable outlets at anon-erosive velocity. Channel type and vegetative <br />cover determine maximum grade. Maximum channel side slopes for temporary diversions aze <br />1:1 (horizontal:vertical) and 3:1 for permanent diversions. <br />Grassed waterways. These aze waterways shaped or graded and established in suitable vegetation <br />to dispose of runoff water without damage by erosion. This practice applies to sites where added <br />capacity and/or vegetative protection is required to control erosion resulting from concentrated <br />runoff. <br />' Straw mulching. Baze, non-vegetated slopes can erode quickly and should be vegetated if final <br />reclamation does not follow in the same season. Straw mulching may be broadcast by hand, and <br />' aids in establishing good vegetative cover by providing temporary erosion control until sufficient <br />plant cover develops. On steep slopes, or where exposed to strong winds, mulch should be <br />' secured to prevent it from being washed or blown away. <br />Straw bale sediment check dams. Constructed with straw bales for low head situations, a <br />' detention storage azea is created which detains stormwater. The primary function of the dam is <br />to intercept and detain sediment laden flow long enough to allow the lazger sized particles to <br />settle out prior to passage of runoff to downstream azeas. Other functions includ storage of the <br />deposited sediment, reduction of the peak flow rate, and diversion to anon-erosive channel. <br />Bales deteriorate within three to six months and aze, therefore, only a temporary control measure. <br />Surface roughening. The practice aids in establishment of vegetative cover with seed, reduces <br />runoff velocity, increases infiltration, reduces erosion and provides for sediment trapping. <br />' Grooving slopes. Grooving is cutting furrows along the contour of a slope. In•egularities in the <br />soil surface catch rain water and provide some coverage of lime, fertilizer, and seed. <br />11 <br />