As the water flows through the gold plant's trommel and sluicebox, it carries the raw materials hauled from the old creek beds. This gold plant is very similar to "The Wizard" used at Holloway Bar with a slowly rotating trommel (the large tube you see here) and a three-run sluicebox to catch the heavy gold as it drops out of the clay and gravel during its run through the plant.
Most gold plants of this design use a small diesel engine to rotate the trommel, which is often the only moving part (other than the water) in the system. However, as most gold processing equipment is "home built and designed", there are many variations on the same theme. One common addition to this system is a large "shaker table" where the raw material is first dumped - just to add one location to better break up the clay and gravel before it enters the plant.
The one common ingredient for most placer mining operations is water. Much care is taken to make the mining system "self contained" to help protect the environment from any permanent damage - so all of the water used in the mining process runs off of the end of the plant into a series of tailings ponds, where the muddy water will eventually filter back into the ground, leaving a layer of organic material.
The composition of this material depends on the type of ground being mined - as this material seems to have a heavy clay component, the remnants of the gold extraction process will be a fine, clay-laced mud, very similar to what you'd get in an old river bed (since that's what's being mined).
Placer mines usually have a series of tailings ponds that are interconnected - in times of heavy mining activity, a lot more water is expelled by the plant than can be absorbed into the ground, so in this case, a spillway similar to what you see in a dam is used to take the overflow and run it into another pond.
No waste water is allowed to escape to preserve the fish habitat - most lakes and streams in this area are fish-bearing and contain trout, grayling, dolly varden, and sometimes even northern pike (as this is the arctic watershed).
Working in the bush presents many difficulties, but a shortage of water is usually not among them. In fact, an over-abundance of water during the spring run-off prevents many of the streams and rivers from being crossed when the water levels are too high. As this is wilderness, there are no bridges, so any bodies of waters must either be crossed if shallow enough, or the trail (road) must circle around it.
This all-wheel drive vehicle has just entered a river crossing and should do fine as long as the water doesn't get any deeper. Most vehicles used in the bush have large tires to prevent them from sinking into the soft ground - but they don't allow them to float.
