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Actions before mining: <br />1. Construct temporary structures (swales and berms) uphill from areas to be <br />mined, to (1) prevent erosion, (2) divert water from active mining areas and <br />(3) convey water to desired locations. <br />2. In some cases, construct permanent structures such as French drains prior to <br />other disturbance, in order to divert and convey water. <br />3. Designate infiltration areas along west edge (of area to be mined) to <br />preserve overburden and natural permeable soils and subsoils (sand and <br />gravel) to prevent undesired ponding of runoff. <br />Actions during mining <br />1. Construct additional temporary structures (swales and berms) on the floor of <br />the pit and in stripped areas to (1) prevent erosion, (2) divert water from <br />active mining areas and (3) convey water to desired locations. <br />2. Divert surface water, as much as possible, to planned and existing ponds <br />where the water can be used for various beneficial purposes, <br />3. Otherwise, divert water to infiltration areas designated prior to mining, and if <br />appropriate, to existing or newly-constructed French drains. <br />4. Control any drainage from the active areas and treat as required by water <br />quality regulations and permits to ensure that no sediment or dissolved solids <br />from the pit is discharged into Mud Creek. <br />5. Keep shale bedrock covered or cover exposed areas quickly to reduce or <br />prevent contact with water. <br />6. Maintain existing ponds to allow for water to be stored on the site for use in <br />mining or for watering of stock, per existing DWR well permits and established <br />water rights. <br />7. Provide temporary detention, sediment, and infiltration basins and use <br />existing ponds (without surface discharge) for plant site(s) to manage <br />sediment and fines from washing materials. <br />8. Construct French drains at the west (downhill) edge of the mining area as the <br />limits are reached, to allow for long-term underground flow of water from <br />east to west and prevent undesired ponding. <br />9. As necessary, provide stockpiles with perimeter ditches/swales and berms <br />with silt fence, straw bales, or rock check dams, to reduce/prevent sediment <br />in any runoff, and reduce soil loss and poor trafficability in other areas. <br />Actions after mining: <br />1. Shape basins, infiltration areas, and permanent ponds (during reclamation <br />(grading) of mined areas) to final configuration to provide favorable <br />conditions in the long-term for dealing with sediment and water flow. <br />2. Complete and fully stabilize French drains, culverts and other permanent <br />diversion structures. <br />Exhibits for 1 12(c) AM-02 Application - M-1994-108 - 2010 - Page 34