Hard Rock Gold Mining

In the paper, I make a detailed introduction to the hard rock gold mining from the rock gold geology, reserves, processing methods, to gold processing equipment. By reading this article, you are sure to have a generally clear and organized understanding of rock gold. Join us!

Hard rock gold is also called mineral gold which is produced in mines. Gold deposits, mostly deposited by hot springs gushing out of the ground through cracks in the rocks, are often sandwiched with quartz in cracks in the rocks. Most of the gold deposits are associated with other metals, including silver, platinum, zinc and other metals besides gold, which was called composite gold before other metals were put forward. Ore gold occurs in different mines and contains different components of other metals, so the fineness varies from 50% to 90%.
According to the structural state and gold content of gold in minerals, the minerals of gold deposits can be divided into three categories: gold ore, gold-bearing minerals and gold-carrying minerals. The so-called independent mineral of gold refers to the gold produced in the form of gold minerals and gold-bearing minerals. It is the most important form of occurrence of gold in nature and the main object of industrial development and utilization. So far, 98 kinds of gold minerals and gold-bearing minerals have been found in the world, but only 47 kinds are common, while only 10 kinds of minerals are directly used by industry.

The easiest way to find rock gold on land or underground is by rock gold detector, this machine is operated by manual, it is very popular to use by small rock gold miners, they will try to find the rock gold or other metals underground, then try to dig up the rock gold ore, then separate out rock gold by small sluice box and washing machine.
For large scale rock gold mining plant, big rock gold detection machine to find the exact rock gold mine position, and blast the rock gold stone out. Then send it to the next rock gold processing plant.

The rock gold ore is very rich in Africa, South America, such as Mali, Sudan, Tanzania, Mozambique, Suriname, Ghana, Congo, Zimbabwe, Zambia, Ethiopia, Peru, Chile, Bolivia, Australia, America, etc.

Gravity Process Flow for Hard Rock Gold Mining
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• Crushing and Grinding stage
  The extracted ore should be crushed by jaw crusher initially and then by the fine crusher. When it gets the reasonable fineness, it is transported into a ball mill by elevating conveyor and feeder and is milled by ball mill. Gravity Process for Hard Rock Gold Mining:
• Classifying stage
  The subtle milled ore gets the next procedure: classification. There is a theory that if the weights of solid particles are different, the sedimentations will be different, and the mixed ore can be classified by a spiral classifier/screw classifier. Gravity Process for Hard Rock Gold Mining:
• Beneficiation stage
  The superfine particles from the ball mill will feed into a shaking table through the hydraulic classifiers, which can ensure different size distribution ore/slurry feed into different riffles shaking table, in order to reach a higher recovery ratio.
  JXSC Shaking Table is one of our flagship mining equipment with more than 30 years of experience. It has a very high, up to 95% high recovery rate which widely used to concentrate free gold.
• Gold refining stage
  Mercury Distiller/Gold Amalgamator is the traditional gold refining machine, widely used to mix the mercury and gold concentrate, in order to get the pure gold, then we can use Gold melting furnace to produce gold bar.

Flotation Process for Hard Rock Gold Mining
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• Crushing and Grinding stage
• Classifying stage is the same as the gravity process.
• Mixing and Flotation stage
  The classified ore gets into a mixing tank for fully mixing. At this stage, the chemical agent for foam can be added. After fully mixing, the slurry will enter into a flotation machine.
  When the flotation machine works, the motor drives the impeller to revolve, so the centrifugal effect and negative pressure are produced. On one hand, ample air is absorbed and mixed with mineral slurry, on the other hand, the mixed mineral slurry is mingled with additive, meanwhile, the foams are thinning, the mineral is bounded with foams, and floats up to the surface of mineral slurry and the mineralized foam is formed. The liquid surface can be adjusted with the height of adjustment flashboard so that the useful foams are scraped with a squeegee.
• Concentrator thickening and drying
  Then gold is separated from others. Since the separated ore is wet, they should be dewatered by thicker initially, and dried by a dryer.

Leaching and Adsorption for Hard Rock Gold Mining
The slurry of ground ore and lime moves into a series of six leach tanks where a sodium cyanide solution is added. The tanks provide sufficient retention time to allow the gold and silver to be dissolved by the cyanide solution. Oxygen is added to assist in this process.

The slurry then moves through a series of carbon adsorption tanks. While the leaching process continues in these tanks, the primary objective is to remove the gold and silver from the solution. To achieve this, carbon is fed through the tanks and the gold and silver adsorb (attaches) to the carbon granules. Carbon is heated to 600 degrees C and fed into the circuit in the opposite direction to the slurry flow, moving from the last adsorption tank to the first. This is because the gold and silver move towards the carbon via a diffusive process. It is necessary to have fresh carbon at the end of the chain, to scalp the gold and silver that has not been removed in the previous tanks.

By the time the slurry reaches the final adsorption tank, most of the precious metals have been removed. The barren slurry, now known as tailings, is pumped to the tailings storage facility. In contrast, by the time the carbon reaches the first adsorption tank it has recovered most of the gold and silver from solution. This‘loaded’carbon is then pumped to the elution circuit where the gold and silver is washed off with superheated water. The washed solution, called pregnant eluate, is passed to the electrowinning circuit. The remaining barren carbon is reactivated by acid washing and kilning and returned to the adsorption tanks.

JXSCmine machinery Company in China has more than 30 years of professional experience at the rock gold process, design full set rock gold ore process flowchart, provides complete set rock gold ore separation machines, can send an engineer to the mine site for equipment installation and commissioning guidance. Have already built many rock gold ore processing plants in Africa countries. Include Mali, Sudan, Mozambique, Suriname, Ghana, Congo, Zimbabwe, Zambia, Tanzania, Ethiopia, Peru, Chile, Bolivia, Australia, etc.
Here to find gold processing solution cases, as for different gold mine conditions and requirements, what machine used, how the gold processing plant configuration.