Tin - Dredging - Malaya has the largest tin dredgers in the world. Out of the 126 dredges pre-war it was considered that 104 could be repaired while 22 must be written off as having no further operating value. The bucket dredge is an endless chain of manganese steel buckets, and weighs up to 835 tons. The operating costs are lower than for any other form of tin mining. Exterior view showing first process of refining. July 09, 1951.