Working a Gold Placer Deposit

The dimension of the deposit will mostly decide how much money will be spent on equipment and what type of equipment will be used. Clearly; a deposit of some million tons will defend the expenditures of much more money than will a similarly rich deposit of several thousand tons. Here we are worry with the smaller operation where some of the equipment will be built on the site. The principal variation in working dissimilar deposits is the means by which the material is mined or moved to the concentrating equipment. If the deposit lays lower or partially lower the water table, a search or a dragline must be used to transport the material. The dragline is much more practical since it is not restricted by the size of material it can pick up.

A break is started with the dragline .The material from the hole is drop near the concentrating equipment or piles up to be later transported to the equipment. The hole is enlarged and deeper until the base of the deposit is arriving. When the dragline can reach no more material it is mined. By frequently touching the dragline the whole area can mine.

If the dragline feeds the screen directly the screen and sluice must be made transportable. If these pieces of equipment are built onto skids they can be transported by a caterpillar tractor so that they are constantly close to the dragline.

 This process is not as cheap because of the extra carrying of material to the concentrating area, and because the tails from the sluice must also be transported back to the pool being dug by the dragline. If the concentrating equipment is constantly close to the pool, recurring the tails is not much of a trouble. At least one hundred tons an hour should be moved with the dragline to make it cheap. The suction exploration is restricted by the size of material it can pick up. Except is the deposit is manly fine material the suction dredge will not be as competent as a dragline. The intake water is moved over the outside of the base of the pool and sucks up material. A screen is placed above the end of the intake plunger to keep rocks from plugging it up. If there are several large rocks nearby very little material will be picked up and the base layers of the deposit will not be arriving. Suction strategy work well only where the deposits is poised of sand and gravel with few large rocks.

A raft is needed to hold the sand pump which is the font of the suction. The material picked up may be extract to the coast to be concentrated, or a screen and sluice box may be set up right on the raft. Except an extremely large sluice is used; it is more cheap to concentrate the material on the raft. The material will be carry only a short space and the tails can be send straight into the pound. The tails should be sending after the raft or away from the suction intake so that they are not picked again. If part of the deposit is over the water line the walls of the pool is constantly damaged and yield into the pond and picked up by the suction pipe.