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Placement of staked straw wattles downgradient of all surface disturbance areas to intercept any surface runoff
<br />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 />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
<br />(6RT only) for the 6RT and 7RT Thickener Underflow Borehole installations have been designated as Small Area
<br />Exemptions (SAE'S), and the limited drainage from these area will be controlled by gravel surfacing, staked straw
<br />wattles, and reclamation /stabilization of the pad areas following well installation. SAE designs for the 6RT and 7RT
<br />Installations are provided in Exhibit 49S, and include upstream and downstream straw bale catch dams for any
<br />trenching activities. Temporary drainage and sediment control measures will remain in -place until vegetation is
<br />sufficiently established to 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 />disturbance areas. Much of the pipeline excavation and borehole pad disturbance will occur in areas that are, or have
<br />previously been, disturbed. For the remaining pipeline trench areas, consideration of soil horizon segregation must be
<br />balanced with the objective of limiting overall surface disturbance. In the interest of minimizing overall surface
<br />disturbance, TC proposes to not segregate and separately stockpile individual soil horizons for the pipeline trench
<br />disturbance, and submits that this approach will not significantly alter soil suitability characteristics, since the
<br />differences between the soil horizons is not significant over the areas to be affected by trenching. For the borehole
<br />drill -pads, individual soil horizons will be segregated, if present. Generally, to avoid contamination of the windrowed
<br />soil material, excavated material will be temporarily placed on the opposite side of the disturbance area.
<br />Soil materials will be replaced following completion of pipeline installation. Reseeding of the disturbed areas will
<br />be completed during the first appropriate planting period following soil material replacement. When no longer
<br />needed to support ongoing or future mining and related operations, the thickener underflow boreholes will
<br />reclaimed by removing the surface manhole structures; plugging and sealing the boreholes, consistent with State
<br />Engineer requirements; cutting -off the casings below ground level, and placing a permanent marker; then
<br />regarding, replacing soil materials, and reseeding the associated disturbance areas. Pipelines will be abandoned in-
<br />place, with the ends of the pipelines cut -off and capped below grade.
<br />18LT Mine Water Transfer Pipeline (TR09 -70) - As a limited, temporary, surface disturbance, construction of the
<br />18LT Mine Water Transfer Pipeline will have minimal impacts on surface water hydrology, relative to runoff and
<br />MR13 -273 2.05 -84.7 12/06/13
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