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DATTLE MOUNTAIN RESOURCES Page 9~1 <br />San Lws Projtcl Technical Specifications <br />9.0 SURFACE WATER CONTROL FACILITIES <br />The Contractor shall famish, transport and install al] materials necessary for con::traction of the <br />surface water control facilities as shown on the Drawings and set forth in the Sped fications, or as <br />directed by the Designer. Items of work include, but are not limited to ditch and trench <br />excavation, embankment cuts, foundation preparation, installation of high density polyethylene <br />(HDPE) corrugated pipe, and backfilling. <br />9.1 Tailings Impouodmeut <br />Ditches, channels, and diversion structures shall be completed to the lines and grades shown on <br />the Drawings or as established in the field by the Designer. Excavation, grading, ind foundation <br />prepazation shall conform to the provisions of Section 5 of these Specifications. Foundation <br />surfaces shall be free of stumps, stones, boulders, rocks, frozen clods or similar ob.~ec[s. <br />9.1.1 Ditches <br />Armored ditches will be used to divert surface water from adjacent basins across. the reclaimed <br />tailings impoundment to the impoundment spillway. Ditches aze shown on the design Drawings <br />for reaches 1 through 7. The locations aze based on preliminary contouring relative to the <br />spillway design control elevation and are subject to change based on the final surface <br />configuration, as described in Section 5.5 of these Specifications. Final ditch locations must <br />divert water from the four primary drainage basins outside of the impoundment. Final ditch <br />locations should correspond with surface grading to provide drainage paths. Ditches should be <br />constructed based on specified flow line elevations at points where drainage; is to be re- <br />established from surrounding basins and at ditch confluences. Ditches should be constructed to <br />the specified grades for each reach and shall be armored with the specified riprap and geotextile <br />fabric as shown in the Drawings. <br />The ditches will extend beyond the perimeter berms at four locations a minimum distance of 25 <br />feet at a 0.5 percent gradient. Grading of the area outside the perimeter berm shall be in <br />accordance with Section 5.5.2 of these Specifications. The extended ditches shtlll have 3H:1 V <br />side slopes and shall be armored with Type 6 material riprap. <br />The ditch cross-sections and specified depths aze shown in the Drawings. Ditch side slopes shall <br />extend to the surface at 2H:1 V for up to 5 feet. Final grading may require deeper ditches to <br />N:\DHALLMAN\SANLUIS~SANLUIS,DOC y-~ SRK Project No. 147}2 <br />