Gold Dredge No. 8 (907/479-6673 or 866/479-6673, www.golddredgeno8.com [1], daily mid-May–mid-Sept.), the only National Historic Mechanical Engineering Landmark in Alaska [2], is just a little larger than its official designation. One of Alaska’s first steel-hulled bucket-line dredges, it was installed in 1928—five stories tall, 250 feet long, weighing over 1,000 tons. The dredge stopped operating in 1959, but it has been completely restored with fascinating exhibits and guides stationed around the dredge. The $15 admission also includes a hearty lunch.
Local placer gold derives from ancient quartz veins once exposed in creek beds, now buried up to 100 feet below the surface. To get to it, first you hose off the surface layer down to two feet with hydraulic cannons or “giants,” then down another few feet as the exposed frozen gravel thaws on its own.
The deeper frozen muck and rock is thawed over a year or so by water pumped through pipes from the surface to bedrock, supplied by monumental aqueducts such as the Davidson Ditch. Once the earth down to bedrock is diggable, a gold dredge is brought in.
The dredge dwarfs even the largest machines in this land of giant machines. It’s a true Alaska-size contraption that looks like a cartoon cross between a houseboat and a crane. An endless circular conveyor of up to 100 steel buckets scoops up the gravel, conveys it to the top end of a revolving screen, and dumps it.
The screen separates the larger rocks, shunting them off to the tailing piles, from the golden gravel, which is sifted from the screen to riffles, where quicksilver (mercury) gleans the gold, forming an amalgam. The riffles are cleaned every couple of weeks, then the gold is further processed and assayed. In the old days during the height of production, the gold would next be shipped to the mint, where it earned $35 per troy ounce.
To get to Gold Dredge No. 8, drive eight miles up the Steese Highway toward Fox, take a left on Goldstream Road, and another left on the Old Steese Highway. Riverboat Discovery and El Dorado Gold Mine have the same owners, so package tours are available.
Links:
[1] http://www.golddredgeno8.com
[2] http://www.moon.com/destinations/alaska