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EXH181T C - paragraph 9 (continued) A 2.8 to 1 horizontal to vertical slope gradient will be maintained during the construction of the tailings dam, which will be raised in successive stages to a maximum height of 30 feet. When the tailings impoundment dam has reached it storage capacity, it will occupy a rectangular area that will have the dimension 400 feet by 260 feet at its longest and widest points This milling complex has been designed to maintain a stable water balance throughout the ore processing and tailings impoundment system. The milling operation will require 4 tons of water for every ton or ore processed in the gravity and flotation concentration circuits. Fresh water will be introduced into the milling process in the grinding circuit (see Figure 1). Most of the water that will be used in grinding and classification, and in the gravity concentration circuit, will be recycled from the thickener tank overflow launder back to the ball mill. Fresh water will also be added to the thickener pulp as it passes from the thickener tank underflow to the flotation concentration circuit. A closed circuit has been planned to recycle the water that will accompany the tailings pumped from the mill to the tailings retention structure. The excess water that accumulates in the tailings pong will be decanted from the water pool and stored underground in the Hazel A. edit. A steel pipe with water decant holes will be used to removed the excess water that collects in the tailings pond. This decantation line will be used to control the water Ievei in the tailings pond, and to keep the water pool as far as possible from the crest of thee, embankment. Additional sections of steel pipe will be connected to the decantation line to regulate the elevation of the water pond as the tailings dam's height is increased. Several seep rings will be attached to the steel pipe to prevent the tailings from piping along the decantation line. The decantation line will be connected with the Hazel A. edit through one of the test holes that were drilled by the U. S. Bureau of Mines. This underground storage area will be used to clarify the decanted water by allowing it to settle prior to recycling the water through the mill. It will also provide additional reservoir capacity for the excess water removed from the tailings pond. The amount of water that will be decanted and stored underground in the Hazel A. edit will be primarily determined by the water balance maintained throughout the processing and impoundment system. The water consumed in the milling process and lost in evaporation from the tailings pond is not expected to exceed 20 percent of the water used in the mill.