Onshore, the Alaska Gold Company has, until recently, continued to employ two bucket ladder dredges, each of 225 liter (9 ft 3)bucket capacity on placer gold production. Gold was discovered in 1900 on the beach of Nome, Alaska, and in the adjacent shallow water of the Bering Seal. The experience illustrates the need to match marine mining equipment to each unique deposit and to delineate the reserves ahead of mining start-up. of gold were recovered from 1987 to 1990, inclusive, when the operation was stopped because of the low gold price and structural failure. Very high operating costs necessitated an elevated cutoff grade and much more drilling than originally anticipated in order to define a dredge course, Altogether, 1I8,078 oz. The throughput rate averaged 457 mshour over 4 years. Sea ice limited operations to the months June through November, reducing the availability to an average of about 70%. The marine conditions were considerably more onerous and the wind/wave conditions grossly exceeded design specifications. The highest gold grades were in the uppermost 2m, and the sediments were much coarser and very resistant (o digging. Ttreoffshore conditions in Alaska, however, were entirely different from those where the dredge had operated previously. With an overall length of 140m and >7,000 hp installed, it could dig to 45m depth at a rate of 2,000 m3/hr. Designed for original use on a very different tin deposit in Indonesian waters, the dredge arrived in Nome in 1986. To mine the marine deposit, WestGold purchased second-hand the world's largest, ocean-going, bucket-ladder dredge, the ‘Bima’. Following the discovery of gold in 1900 on the beaches of Nome, a major offshore extension was partially drilled in 19.
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