PROJECT: McArthur River Dredging
SCOPE OF WORK:
Mobilise our stainless steel cutter suction dredge along with booster pump, 600m of 200mm polypipe line, workshop & spares container.
This was a two dam project, Dam 1 (CRP) was 90% full of concentrate run off and was considered of good enough quality to reprocess. We dredged to designated tie in point in the plant and the material was supplementary to normal feed.
Lake Archer had a quantity of already processed Lead Oxide and was stored in a HDPE lined dam known as lake archer. Our task was to produce a slurry at a rate of 45l/s @ 10% Sg to a holding tank prior to it going through the plant for final processing.
Lake Archer presented a very low pH of 2, and it was to be managed to a level of pH 5 or higher. Several methods were to be used. Initially remove the water and refresh it with a pH neutral water. Lime dosing or micronised mineral were also considered as methods to be used in maintaining the required level.
During the dredging process of the CRP, a lot of rock was being delivered to the plant. The dam was a natural earth dam and by the nature of its construction it was peppered with rock and other debris. This resulted in considerable down time clearing the rock in the plant. It was decided to cease dredging until we manufactured a suitable rock box was made and delivered to site. Overall the dredging operation as conducted was successful, and the learning form the project were valuable.