Laserfiche WebLink
Historic Tailings Replacement <br />Following pond construction, liner installation, and overliner installation, the historic tails, <br />magnetite, and clay pad will be placed back in the Phase 1 TSF. UMC is permanently installing <br />a tailings thickener on the southeast corner of the mill building for use in the mill tailings circuit. <br />The historic tailings will be loaded by skid steer, placed in the tailings thickener, water added to <br />approximately a 70% solids slurry and the resulting slurry pumped (using the designed mill <br />tailings disposal system) into the newly constructed TSF. The clay liner pad under the historic <br />tailings will be placed in the TSF in the same manner. <br />OA/QC <br />The Quality Assurance /Quality Control (QA/QC) Plan for the TSF is as follows. <br />Onsite Personnel <br />UMC's mill superintendent or qualified designate will be on site at all times construction <br />activities are being conducted by UMC crews or by contractor crews. UMC has retained <br />an Owner's Engineer, who is a Registered Professional Engineer and a Professional Land <br />Surveyor in the State of Colorado, to monitor the contractors. UMC is contracting <br />clearing and grubbing, topsoil removal and storage, impoundment excavation and <br />embankment construction, clay material segregation and clay liner construction, leak <br />detection and sump construction, impoundment liner installation, and geotextile liner <br />installation. UMC crews will place overliner material on the geotextile liner, construct <br />and place ballast tubes on the impoundment sides, install tailings slurry pipes to the <br />impoundment, and install the decant water pumping station. <br />General Site Preparation <br />• Stake tree clearing/topsoil removal limits for TSF. <br />• Stake grubbing limits for existing tailings storage pad. <br />• Slope stake storage pad for existing tailings. <br />• Oversee tailings storage pad layout and grading. <br />Clearing, Grubbing/Topsoil Removal /Storage <br />• Performed by contractor, monitored by Mill Superintendent and/or Owner's <br />Engineer. <br />• Quantity check between planned and actual material moved. <br />Impoundment Excavation and Embankment Construction <br />• Performed by contractor, monitored by Mill Superintendent and/or Owner's <br />Engineer. <br />• Slope stake exterior and interior embankments. <br />• Red top embankment slopes as being constructed by contractor. <br />• Grade top of sub base on interior slope and bottom of impoundment ( +/- 1") on <br />50' grid. <br />M1990 -057 September 27, 2011 <br />