Dredge No.4 is a Canadian Historical Site, in which guided tours are lead through the 100 year old machine. The dredge is about the size of a small hotel, but has a large arm extending out of the back of it to remove waste rock, or "slag". The dredge was used to salvage gold in the Yukon Territory's Bonanza Creek - the place where the Gold Rush of the late 1800s began. The dredge ran for 60 years and moved 19km along the creek, relocating over 5 square kilometres of debris. Out of all that effort, the dredge salvaged 8 square feet of gold dust, worth about $5 million in the times of the early 1900s. This is a very large number compared to the 25¢/hour the workers made.