Sumpter Valley Gold Dredge - Wikipedia
Still, it cost more to run than the gold could pay for. The last dredge closed in 1954, more than $100,000 in debt. In its lifetime this dredge made $4.5 million at $35 per troy ounce. That is 128,570 troy ounces which, at the recent value of $1,400.00 per ounce, would be worth $180,000,000.