connecting into the 1MN TUF Pipeline, and will generally fall within the previous disturbance areas for the
<br />Haulroad C corridor and the 18 -Left Mine Water Transfer Pipeline. Limited areas of pipeline construction will fall
<br />within the Foidel Creek Stream Buffer Zone, and both general and specific BMP's will be used to prevent adverse
<br />impacts to the hydrologic balance. Electronic moisture sensors, along with pump controls, and shut-off valves
<br />provide for timely detection, shut-off, and isolation of the pipeline in the event of pipeline leakage. Access/inspection
<br />manholes and pipe -tees for the moisture detection system will be located at key points along the pipeline routes.
<br />During construction, and for the minor surface structures that will remain during mining, drainage and sediment control
<br />will be provided by Alternative Sediment Controls (ASC's) consisting of combined Best Management Practice (BMP)
<br />measures. As appropriate, ASC designs are included in the design exhibits for each installation. BMP's for the
<br />construction activities include (BMP's for any stream buffer zone areas include the general BMP's identified, as well as
<br />specific BMP's* as noted):
<br />• Minimizing the area of surface disturbance
<br />• Placement of stream buffer zones markers prior to disturbance in or immediately adjacent to buffer zone areas*
<br />• Scheduling of construction activities during the dry summer or early winter periods
<br />• Placement of staked straw wattles, silt fencing, or plastic silt barrio materials downgradient of all surface
<br />disturbance areas to intercept any surface runoff and trap associated suspended solids
<br />• Installation of the Foidel Creek, RCR27, and railroad spur pipeline crossings as either trenched or bored/jacked
<br />pipeline crossings under Foidel Creek, RCR27 and the railroad spur (if trenched, TC will obtain required
<br />CDPHE-WQCD Temporary Construction Discharge Permit and will complete required USACE notification
<br />• Windrowing or soil and excavated materials immediately adjacent to the pipeline trench, and progressive
<br />backfilling and soil replacement as pipeline installation proceeds
<br />• Restrictions on storage or transfers of petroleum products within or immediately adjacent to buffer zone areas*
<br />• Soil replacement and stabilization with either the standard rangeland or riparian seed mixtures (as appropriate)
<br />in a timely manner following completion of construction activities
<br />Construction -related surface disturbance will be limited to soil removal and windrowing from the pipeline trench
<br />alignments and stockpiling for the borehole pad areas, excavation of the trenches and temporary stockpiling of
<br />excavated material adjacent to the trenches, minor cut/fill grading to establish the borehole drill -pads and excavation of
<br />temporary cuttings pits, and excavation of temporary pits (within existing disturbance areas) for pipeline boring or
<br />jacking operations at the Foidel Creek, RCR27, and railroad spur pipeline crossings.
<br />Where pipeline disturbance traverses steep slopes, additional staked straw wattles will be placed on -contour to limit
<br />overland flow following revegetation seeding. Drainage and sediment control for the associated minor surface
<br />structures (borehole surface casings and any manhole(s)) will also utilize BMP's including the vegetative filter
<br />provided by temporary vegetative stabilization, and berms and/or wattles, as appropriate. The pads and access road for
<br />the 6RT, 7RT, l MN, 2MN, and SWMD thickener underflow borehole installations have been designated as Small Area
<br />Exemptions (SAE'S), and the limited drainage from these areas will be controlled by gravel surfacing, staked straw
<br />wattles, and reclamation/stabilization of the pad areas following well installation. SAE designs for these installations
<br />are provided in Exhibit 49S, and include upstream and downstream straw bale catch dams for any trenching activities.
<br />Temporary drainage and sediment control measures will remain in-place until vegetation is sufficiently established to
<br />effectively control runoff, erosion, and sediment loss.
<br />As relatively small isolated surface disturbances, the additional disturbance required to construct ditches and
<br />sedimentation ponds to intercept, route, and treat runoff from thickener underflow pad and road areas, is not warranted.
<br />Similarly, for the associated temporary linear pipeline disturbances, construction of ditches and ponds to control runoff
<br />is impractical. Much of the EMD Thickener Underflow Pipeline disturbance will drain naturally to existing
<br />Sedimentation Ponds E, F, and G, and the majority of the drainage from pipeline areas is effectively isolated from the
<br />nearest drainage (Foidel Creek) by the existing raised railroad bed. The proposed BMP's have proven effective in
<br />controlling runoff and sedimentation from similar disturbances. Special design, construction, and operational measures
<br />have been incorporated in the design plans to assure that there will be no discharge or mixing of mine water with
<br />surface drainage.
<br />Following installation of appropriate ASC's for each portion of the project disturbance, available soil materials will be
<br />bladed from any new disturbance areas and temporarily windrowed or stockpiled on the upgradient edge of these
<br />TR16-86 2.05-84.7 11/21/16
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