ask anything, page-16

holdonman

Not quite right. The 'water balance' requires a certain amount of water by volume be maintained throughout the whole circuit (plant, pipes, dams etc). If there is excess water in the circuit this will evidenced by higher volumes in the dam. This excess water is usually decanted off or pumped away (the Siana system has the ability for both). The management issues relate to the ability to maintain enough water in the dam to have it available to return to the plant. It's a fine balance if you are only operating one small dam, much less of a issue if you are operating larger dams (or two dams of larger volume). The important thing is to allow the tail to beach. Look at the Google Earth satellite image of 16/10/12 to see the discharge and beaching of the tail and more importantly the development of the supernatant pond for the return water (to the south).

I would have to check the detailed water balance calculations but IMO the system was capable of 2,000tpd if carefully monitored. Short bursts of higher throughput are ok if you are testing some part of the circuit. But from a dam stability perspective the Siana tailings dams were designed for a 3.0 metre freeboard (look at the Google Earth image referred to above to see an example of over 3 metres). Water balance management and the freeboard are the most important aspects to safe tailings dam operation. But ultimately RED needed the other dam to come on line and alas it was decommissioned. The rest is history as they say!