The introduction of the first tin dredger in 1907 allowed the tin mining industry on Phuket to expand into a vast new area that had previously been untouched. Several types of dredges were used locally. Hydraulic dredges sucked the ocean floor for the alluvial deposits of tin through a pipe; separated the tin and discharged the spoil on the shore through a floating pipeline. Elevator dredges employed an endless chain of small buckets to scrape the ocean floor and separate the tin ore from the rest of the spoil; which was discarded back into the ocean. The coastline of Phuket and the surrounding ocean floor have been dramatically altered by dredging for tin.