Equipment needed for Small Scale Gold Mining
Panning makes use of water to separate high gold particles from any other lighter particles in the medium sized pan. With this process sediment and ore thought to have gold is then placed on the wide and curved pan all along with water. Miner moves this pan in the series of the motions made to eject the lighter sediments. Because of its high density, the gold stays on the bottom of a pan as the lighter material gets ejected all along with the water. After series of some successful iteration are completed, gold is exposed on the pan for a miner to recover. The panning method works best when the gold is coarse and liberated. Under the right conditions, panning will produce a good grade concentrates or liberated gold. After that, miners will use gold recover techniques like direct smelting, even though many panning operations will lead to recoverable gold directly. Panning gives miners the low cost way of gravity concentration, however it needs skill and time to be very effective. The major drawback of panning is that the miners should pan very small amounts of the concentrate. Thus, panning often is done after some other methods of the gravity concentration like sluicing have been completed.
Sluices generally use water to clean ore and alluvium down the series of some angled platforms. When the water washes the sediment down the sluice, the gold particles will sink and then captured by the material covering the bottom of a sluice, or carpets. The sluices are generally inclined at 5 - 15 degree of angle. When moving water goes down the sluice, it creates high force and keeps all the gold particles to sink easily. For such reason most of the gold gets captured in the beginning of this sluice. The carpets and other capturing devices in the sluices bottom are removed and then washed in the bucket in order to remove any captured dense material. The sluice design will lead to the higher recovery of the gold if force of water traveling by the sluice gets decreased. The series of rifles will help to break the flow for improving the recovery. The zig zag sluice achieves it by creating the drop between first or second platform, which disrupts the water velocity when it travels to the sluice.
The simpler alternative to a zig zag sluice will be the combination of 2 sluice surfaces. First gets tilted at the steeper angle compared to the second one, reducing the water velocity when it hits on the second sluice, and increasing the gold recovery. The sluices are relatively costly or affordable that depends on the complexity of its design. Some simple sluices are the single angled platform and others are quite elaborate.
The shaking tables are the elevated tables that are tilted on one side with the raised ridges that run horizontally down the length. The mineral feed (crushed sediment or ore) and water gets released. Water washes this feed down on the table. As the material gets washed down, the specialized grooves trap the gold and direct this to the collection points located on the table side as the lighter minerals get washed away. During the process, the table is shaken continually by the motor to agitate this material and help with separation of the gold particles. The shaking tables are quite effective and will concentrate good amounts of ore in a single time, giving a high grade of concentrated and the liberated gold, however they are very expensive and need experience to function.
The spiral concentrators are quite specialized pans tilted at an angle with the spiraled grooves. Spiral grooves in a pan lead to its center where the hole gets connected to the container to catch the material. The motor is used to rotate a pan continually as the concentrate is fed on the pan by the operator. The pipe horizontally extends over the pan, then sprays water all along the pan surface when the concentrator spins. Water washes the lighter particles down its spiral concentrator in the bucket whereas denser particles, like gold, are then carried by spiral grooves of the concentrator. After the process is repeated many a times, the operator will get the high grade of concentrate, and liberated gold. The spiral concentrators are very simple to operate and do represent the large capital investment compared to panning and sluices.
The vortex concentrators make use of rotating water flow to separate the lighter materials from the concentrate or remove them through the raised drain hole. The vortex concentrator is the circular tub with the water input on its side and raised drain in the center. This tub is full of water until this reaches to the level of the drain hole. After that concentrate gets added in the thin layer over the bottom of a bowl. Water is then pumped in the side input, and creating the rotating water vortex that drains into the center. Vortex pulls the lighter material on the top from the bottom and out the drain hole. Denser materials like gold remain in the bottom of the tub. After a miner sees gold left at the bottom the water source gets turned off and gold is set to get removed.
Miners should pay close attention to the amount of the water flow that goes in the tub. If the velocity is too high, then water will carry the gold particles away from the bowl and it can lead to gold losses.
Chemical Guide and Materials needed to Extract Gold Small Scale
Most of the concentration methods generally rely on a high density of the gold relative to many other minerals in the ore and alluvium mixture. And these are referred as the gravity methods. The magnetic or the chemical properties also can be exploited to improve the concentration. Every mining operation is very unique. The concentration methods should be selected just after considering certain factors like the kind of ore and sediment, minerals present, the size of the gold particle, and availability of the electricity and water.