Google image search brings up tons. I expected it to be a semi-enclosed structure (think log flume), but it turns out it's really just an absurdly long flat con

Google image search brings up tons. I expected it to be a semi-enclosed structure (think log flume), but it turns out it's really just an absurdly long flat conveyor belt, carrying dust and soil more than the "ore" I'd imagined (although some photos show more defined rocks and ore).