2012-12-03_REVISION - M1980244 - Laserfiche WebLink

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Mr. Tim Cazier, DRMS Page 3 designed and approved under Amendment No.10. Please see Attachment No. 1 - Block Flow Diagram, Drawing No. 10- 100 -03, which outlines the primary conceptual flow paths. Aditional drawing eclosed for reference are: Attachment No. 2 — Figure 1 Grading Plan; Attachment No. 3 — Figure 2 Cross Sections; and Attachment No. 4 — Drawing No.65- 702 -20 PSES Equipment Layout. The following is a bit more detailed explanation of the designed flow path and maximum flows: A maximum of approximately 20,000 gpm of flow from the pregnant solution head tank ( "Preg Tank ") will proceed to the Process Solution ( "PS ") Stabilization tank within the PSES. This will allow the PS to reach an equilibrium state within the tank. Approximately 4,000 gpm of PS will be directly diverted to the Splitter Box, located at the head of the Comag Trains. Approximately 16,000 gpm of PS will be pumped to the AGADR to be processed in the existing carbon trains, and then proceed back down to the PSES to the Splitter Box. The aggregate flow of a maximum of 20,000 gpm from the Splitter Box will be distributed to (2) two identical Comag Trains. Each Comag Train consists of one primary vessel sub - divided into (4) four sections designed to mix the solution through a horizontal serpentine flow path. A coagulant is added in the first section of the tanks, magnetite is added in the third section of the tanks, and a flocculant is added in the fourth section of the tanks. Flow then proceeds to the Comag Clarifier. The resulting liquid fraction, known as Enhanced Barren, of maximum of approximately 20,000 gpm is pumped back to the Barren and Enrichment Tanks to be distributed on AGVLF as normal. The product solid component, still quite high in moisture content, will be pumped to the Gravity Thickener. The liquid component from the Gravity Thickener will return to the Comag Trains as makeup water for re -use. The product component (3 -6% solids) from the Gravity Thickener will proceed to the dewatering phase which is a filter press, where a polymer will be added. The resulting dewatered product will be transported off -site for metals recovery. The remaining tanks and storage features will contain relatively benign flocculants, coagulants and product sludge. An important safety feature of the piping between the AGADR and the PSES is a set of valves that close in the event of a loss of power. Incidentally, the AGVLF water balance is not impacted by TR -10 -01 since maximum flow rates will not be changed. Two page revised versions of Amendment No. 10 to Permit M- 1980 -244 Project Description page 8 -4 are enclosed as Attachment No. 5 — Project Description Page 8 -4 with Tracked Changes and Attachment No. 6 — Revised Project Description Page 8 -4. Additional Chemicals that will be Added as a Result of the PSES The MSDS are attached for the following reagents which will be introduced in the PSES: • Magnetite — Attachment No. 7 • Aries 2607 Coagulant — Attachment No. 8 • Aries 1668 Flocculent — Attachment No 9