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3.0 Treatment Tanks and Piping <br />Three-inch diameter HDPE pipe was extended from the mine portal to the Untreated Water <br />Tank. This line was fused over its entire length (about 500 feet) and buried in a trench at a depth <br />of four to five feet. Atwo-inch return line consisting of fused HDPE pipe was installed along <br />side the three-inch pipe to allow pumping back to the mine should the water in the tank be <br />needed at a later time for underground drilling and dust control. Two 6-inch diameter HDPE <br />pipes were also installed in the road crossing to facilitate installation of future drainage controls <br />from the ore pad to the Untreated Water Tank. Burial of these lines is expected to minimize the <br />potential for pipe damage and freezing. <br />Three large modular treatment tanks, manufactured by ModuTank Inc., were constructed on site <br />(see Figure 1). The mine water is pumped into the Untreated Water Tank at its southeast corner. <br />A pump is located in the northwest corner of the tank that, in turn, pumps the water from the <br />Untreated Water Tank to the Treatment Plant. The distance between the inlet and outlet of the <br />Untreated Water Tank allows for some settling of suspended particles prior to water treatment. <br />As mentioned above, the Treatment Plant discharges into a Settling Tank, where natural <br />contaminants precipitate out of solution as a sludge. The treated water then overflows into the <br />Polish Tank. The water in the Polish Tank is discharged via either gravity overflow or pumping <br />to the adjacent ephemeral drainage. The water in the Polish Tank is to be sampled weekly to <br />verify that discharge standards are being met. <br />The modular tanks were constructed in the following stepped manner. Photographs showing the <br />construction of the Settling Tank are presented in Attachment B. <br />1. The area was stripped of topsoil and the underlying subsoils were graded to create a level <br />platform. <br />2. Crusher fines (i.e., squeegee) was placed over the graded area and fine graded to create a <br />uniform surface with no protrusions or sharp edges that could puncture the liner system. <br />3. The wall panels for the tank were erected and secured in place using steel battens and <br />anchor plates. The anchor plates were secured to planking with each anchor being <br />