The unpaved road (maintained for 16km/10mi) along Bonanza Creek winds through huge piles of tailings, or washed gravel refuse, left by the mining dredges. An enormous wooden-hulled, bucket-lined machine, the dredge consists of four basic parts: a barge; a series of steel buckets to excavate the gravel in front of the barge and deliver it to the barge's housing; the housing itself, where gravel was washed with water and the gold recovered; and a conveyor, or stacker, to disgorge barren gravel behind the barge.