Gold dredge

Gold dredge
Gold dredge, Golden Bay, by the Tyree Studio, ca. 1900. Alexander Turnbull Library. 10x8-0508-G

Description

Part boat, part excavator, New Zealand was the first place in the world where gold dredges were developed and used like this example here, the Golden Bay Dredge. The first steam powered dredges worked the Clutha river in the early 1880s. Other successful gold bearing areas dredged included the West coast where the Grey River dredge (New Zealand’s last gold dredge) operated up to 2004 then was recommissioned in 2009 finally stopping work in 2011.

Discussion

How did this sort of gold dredge work?