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capacities of the processing machinery that were installed in the m'1- ~'^g facil- ity. This information determined the positions of the machinery with respect to one another, and the quantities of ore and water that are in transit at every point throughout the mill. Power requirements for each piece of equipment established the sizes of the motors that are connected with the milling machin- ery. Laboratory experiments, pilot teats, and practical experience were also factored into the choice of this flow sheet, which resulted in the final mill design. Ore from C.O.M. Inc.'s mines is transported tq the millsite in a dump truck, and unloaded into one of two coarse ore bins. These ore bins feed the crushing plant, which incorporates primary and secondary crushers in a closed~ircuit. After crushing, the ore is stored in a fine ore bin with enough capacity to insure an 8 hour supply of ore for the grinding and concentrating circuit$ of the mill. This fine ore is then conveyed to the grinding cirouit to complete the comminu- tion process. Fresh water is added to the ore for wet grinding in a ball mill that ie in closed~ircrrit with a spiral classifier. Gravity concentration follows the grinding circuit, with separation being accomplished by a double jig, a rag plant, and a shaking table. The gravity concentrates from each machine in this sec- tion of the plant is pulled from the milling circuit for collection and further treatment. The overflow from the shaking table carries the suspended, finely divided fraction of the pulverized ore to a large thickener tank. This thickener tank serves two important functions. It clarifies the mill water, which is re- turned to the ball mill for recycling in the gravity circuit, and it increases the concentration of the suspended solidB prior to their flotation. The clarified water overflows a peripheral launder, while the solids settle on the bottom of the tank. Four rotating radial arms with blades rake the settled solids towania an outlet at the center of the bottom of the tank. These rotating blades also assist in the compaction of the settled particles, produce a thicker underfloor, and promote faster clarification of the mill water. A diaphragm pump ie used to lift the thickened pulp to a bank of flotation cells, where the concentration process is completed. Standard flotation reagents such as pine oil, soda ash, and xanthate are used in the flotation cells. The tailings from the flotation circuit are pumped to the tailings pond, and the final concentrate pulp is col- lected for filtration. A disc vacuum filter dewatera the flotation concentrate, which is shipped from the millsite for further treatment. C.O.M. Inc.'e mill was designed to have the capability to process 50 tone of ore is a 24 hour period. Because the crushing plant section of the mill is able to crush enough ore in a single 8-hour shift to furnish the grinding circuit of the mill with a 24-hour supply of fine ore, it will only be operated one shift a day. In order to achieve efficient grinding, maintain the ratio of concentration, and in- sure ahigh level of recovery, the grinding and concentrating circuits will be operated continuously. Initially, the milling facility will be operated 3 or 4 days a week for 24 hours a day. 'This schedule is based upon producing 50 tons of ore a day from C.O.M. Inc.'s properties.