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1 <br />1 <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br />1 <br /> <br />1 <br /> <br /> <br />4.0 DEVELOPMENT AND OPERATIONS <br />During the developmental and operational phases of the Yankee Gulch Project it will be <br />necessary to implement and maintain adequate erosion and sediment controls. This section <br />discusses the disturbance development sequence and types of erosion and sediment controls <br />that will be placed during site development and operations, and the inspection and maintenance <br />that will be perforated to ensure their effectiveness during these project phases. <br />4.1 SURFACE DISTURBANCE DEVELOPMENT SEQUENCE <br />During initial land disturbance specific activities will be preferentially accomplished. Perimeter <br />erosion and sediment controls will be constructed first prior to other surface disturbance <br />activities. Next, roads will be constructed with appropriate sediment and erosion controls <br />incorporated during construction. Simultaneously with road constmction and as needed for the <br />construction of erosion and sediment control structures, soil will be salvaged where suitable <br />reconstruction materials exist After these preparations have been completed, the development <br />of mining extraction or processing structures and facilities associated with the well field or <br />facihty areas will proceed. Placement of erosion and sediment control structures, soil salvage <br />and storage, and the construction of roads will parallel the development of the well field and <br />facilities areas. The types of erosion and sediment control structures to be used during each <br />preparntory stage are described below. <br />4.2 PERIMETER EROSION AND SEDIMENT CONTROLS <br />During initial site development the perimeter of the area to be affected by mining development <br />activities will be delineated in the field. Structures will be placed to divert undisturbed surface <br />runoff around the disturbance area when this is feasible. When diversion is not possible, <br />adequate structures will be provided to route runoff safely through the area to be disturbed. <br />Such drainage stmctures will control erosion and sedimentation within the disturbed area. <br />Concentrated flow structures such as berms, ditches and terraces may be used to redirect flows <br />around disturbance areas (Appendix C). Diversions will be used to reroute all perennial and <br />intermittent surface flows. Ephemeral channels may be diverted if it is expected they will <br />receive runoff that could interfere with or jeopardize development or operational activities. <br />Diversion of ephemeral flows will take into consideration the size of the contributing watershed <br />and ffie probability of receiving precipitation capable of producing runoff that would interfere <br />with development or operations. <br />While necessary diversions are planned and constructed, silt fence will be placed along the <br />' perimeter as the primary method of temporary sediment control (Appendix F). Care will be <br />taken to provide adequate outlets, especially where small drainages are crossed. Sediment <br />[reps will be used where larger flow volumes are expected during development Sediment <br />traps may be placed in series when necessary to capture anticipated sediment volumes. These <br />' structures will serve collectively as primary temporary erosion and sediment controls during the <br />development stage. Interim controls will be placed at the end of the development stage. <br /> <br />1 <br />' American Soda LLP. 4- I <br /> Soil Conurvado0. EIOSIOn and Seditnen[ <br /> Control, Retlatnanon, and Revegetadon flm <br />' lXtolxr 28. 1998 <br />