Gold mining in modern riverbeds and terraced gold deposits and amalgamation of re-elected concentrates

Modern mining riverbed, large sand terraces gold deposits using gold mining ship. One of the basic conditions for the application of gold mining is that the deposits are best distributed in modern waters such as rivers and lakes. When the groundwater level in the location where the deposit is located is high or the water source can be solved, the open-air pool can also be excavated by the gold mining vessel, so that the hull floats in the artificial water pool for operation. Large-scale new gold mining vessels designed in modern times, each with a capacity of 600L, can be mined to a depth of 42 to 50m below the water level. Each gold mining vessel can handle gravel with an annual capacity of 5 million m3, and the per capita mining efficiency is equivalent. More than 6 times the efficiency of hydraulic mining. Because of its large capacity to handle gravel, and the mining cost is only 55% of hydraulic mining, it is also cost-effective to use it to mine 0.1g∕t of gold.

Gold mining gold was first introduced in New Zealand in 1870 and subsequently in the United States (1890), the former Soviet Union (1893), Australia (1899), Ghana (1901) and Malaysia (1912). Nowadays, large-scale rich sand mines in some countries have been harvested, and the output of sand ore mined by gold mining vessels is not large, accounting for only 2.5% of total gold production. In China, with the development of national construction, mining The gold workers designed and built all kinds of gold mining vessels, including China's first double-boom gold mining ship, which has twice the production capacity than the single-barrel gold mining vessel of the same class bucket capacity. The gold mining vessel has become the main mining equipment of China's gold and gold mines, and the amount of gold produced has reached more than 60% of the total gold production of sand gold mines.

Type gold mining ship classification to mining machinery chain bucket, suction, mechanical shovel and grab four. In order to exploit the marine gold deposit, Zimbabwe is equipped with a 25.4cm (10 inch) diameter cutter suction gold mining vessel with a mining depth of 60m and a production capacity of 230m ³çŸ¿h ore.

The chain bucket gold mining vessel has the least agitation during underwater mining and is stable to the mine. It is the most ideal equipment for mining gold mines. The mining equipment of the chain bucket gold mining vessel mainly includes the mining bucket line and the separation clay. The coarse-grain sieve with coarse gravel, the re-selection of gold recovery- mercury equipment, and the four-part conveying line for the concentration of tailings and gravel containing no dissociated gold. Such gold mining vessels are mainly classified by bucket capacity. The large-scale gold mining vessels with a bucket capacity of more than 250L and the small gold-mining vessels of less than 150L are listed in the following table.

The main technical indicators of the chain bucket gold mining ship

In Western countries, the production practice of Bulolo Gold Mining Co., Ltd. may be representative, and the process used is shown in Figure 1.

Figure 1 Buluo Luojin Gold Co., Ltd. process of recycling gold

The gravel produced by the gold mining vessel was first removed by a coarse sieve of 2.1 m × 11.6 m and a diameter of 6 mm. The undersize product was treated by a double-platen rocking mechanical chute and a Hungarian shaker. The total area of ​​the chute and shaker was 214 m ² . Pure mercury is periodically added to the clean amalgam plate on the top of the chute and shaker.

The shaker tailings were sent to 20 sets of Placer 107 cm jigs for rough selection. The maximum particle size of the feed is 5-6 mm, and the tailings of the jig are discarded. The coarse concentrate was selected in two groups of three series of Cranglc 61 cm jigs. The selected concentrates are mixed with mercury and the mercury is mixed with mercury. The tailings are discarded.

The tailings after mercury amalgamation are sent to two series of Klanger 30cm jigs. The obtained concentrate is selected by a 46cm×91cm Hardinge ball mill and returned to the selection. Jig processing.

The crude amalgam obtained from the amalgamation plate is treated by the amalgamation cylinder and then enriched by the amalgamation plate, and then the amalgam is placed in a distillation tank to evaporate the mercury. The distillate slag is remelted into a combined gold ingot of 500 ounces (about 15 kg) each. In the gold mining process, an average of 0.38 g of gold was recovered from each cubic meter of gravel. Due to the large change in the grade of the sand ore, the recovery rate of gold is equivalent to 100% to 120% of the calculated grade of the drilling sampling result. The recovery rate of gold in various operations is related to the particle size of gold. That is to say, the coarser gold is mostly recovered on the moving bed, and the recovery rate of gold on the jig only accounts for 3% to 20% of the total gold recovery rate.

The process developed by the former Soviet Irkutsk Institute for a clay-bearing gold deposit in the Yenisei River is shown in Figure 2. Gold dredger mining or hydro-mined ore, pulp like to convey to the beneficiation plant for beneficiation. Since the pulp contains more than 50% clay, washing is difficult. Therefore, the slurry is first pumped into the storage pond to remove a large amount of fine mud and water from the overflow. The grit is then broken and sieved by a vibration shredder. The -2mm slurry was removed by a hydrocyclone - 0.074mm of slime to obtain -2 to +0.074mm ore (28%). Then, the concentrate is selected by using a spiral chute with the largest capacity for processing fine-grained ore, so as to improve the recovery index of 0.1 mm fine-grained gold. Since the heavy mineral concentrate containing up to 12kg / t, where mainly iron oxide and iron hydroxide, so that heavy minerals concentrates selection of wet magnetic separator, non-magnetic product concentrate output, and then by shaking Featured After that, the gold is recovered by a wind shaker or amalgamation. +2～-16mm ore, after mineral processing by МОД-2II jig, the concentrate is sent to the chute for selection, and the produced chute concentrate is sent for reprocessing.

Figure 2 Selection process for clay-bearing ore

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