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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 — - - - - -- -- - - -- -
<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 pad and access road for
<br />the 6RT Thickener Underflow Borehole installation have been designated as a Small Area Exemption (SAE), and the
<br />limited drainage from this area will be controlled by gravel surfacing, staked straw wattles, and
<br />reclamation/stabilization of the pad area following well installation. SAE designs for the 6RT Installation are provided
<br />in Exhibit 49S, and include upstream and downstream straw bale catch dams for any trenching activities. Temporary
<br />drainage and sediment control measures will remain in -place until vegetation is sufficiently established to effectively
<br />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, TCC 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)
<br />As a limited, temporary, surface disturbance, construction of the 18LT Mine Water Transfer Pipeline will have minimal
<br />impacts on surface water hydrology, relative to runoff and sediment contributions. It is anticipated that a maximum of
<br />300 feet of pipeline trench will be open at any given time. Soil removal and windrowing from this limited pipeline
<br />construction area will create a shallow (approximately 1.0 foot deep) depression that, along with the trench excavation,
<br />will tend to contain any runoff from direct precipitation, as well as any minor amounts of run -on from adjacent areas.
<br />Where pipeline construction approaches Fish Creek or minor ephemeral/intermittent drainages, the specific BMP's and
<br />•general protective measures previously detailed for the 18LT Pipeline, and outlined for pipeline disturbances will be
<br />utilized to control surface runoff and sediment. Surface disturbance areas associated with pipeline construction will be
<br />reclaimed concurrently with ongoing pipeline construction, and regraded surface areas will be left in a roughened
<br />condition, to control runoff and erosion, until they can be seeded. As a very limited disturbance area (a maximum of
<br />MR10 -251 2.05 -84.7 05/27/11
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