Gold in nature mostly exists in the form of a single substance, with occasional metal compounds such as selenium, tellurium, and antimony, but non-metallic compounds are extremely rare. Gold mines are mainly divided into two categories: placer gold mines and rock gold mines, and rock gold mines can be further divided into quartz vein type, broken zone altered rock type, fine vein impregnation type, and quartz-calcite type. In view of the characteristics and beneficiation pain points of different types of gold mines, MINGDER ore color sorter and artificial intelligence sorting machine provide customized solutions to promote the upgrading of the beneficiation process to high efficiency and greenness.

I. Placer gold mine: saving water and increasing efficiency, solving the problem of resource recovery.

Placer gold mines are formed by long-term water erosion and wind erosion deposition of primary gold mines. According to their genesis, they can be divided into gravity sand, flowing water sand, glacial sand and coastal (lake) sand. The beneficiation of placer gold is mainly gravity separation and enrichment. Most of the gold sand in China is flaky, or because of the long history of sand mining, the rest are flaky fine particles. Easy-to-select placer gold mines should have more sand and less mud, coarse sand and fine gold, otherwise they are considered difficult to select. In China, water guns and sand mining ships are usually used for sand mining. Due to low cost and large scale, boundary grades are usually not required. Generally, industrial grades of 0.1g/t (0.15g/m³) can be mined, and 0.3g/t placer gold mines are already rich mines. Placer gold mining cannot be separated from water, and whether water can be recycled is the main factor affecting the cost of placer gold mining.

II. Rock gold deposits: Classification and implementation to overcome the bottleneck of mineral processing technology.

From a geological perspective, rock gold can be roughly divided into three categories: igneous rocks, sedimentary rocks and metamorphic rocks. Among them, my country is dominated by igneous rocks and metamorphic rocks, and there are fewer sedimentary rock gold deposits. According to the data of previous explorations, the gold level in igneous rocks decreases with the acidity of the rock. The highest content is dunite and peridotite, followed by diorite and basalt. The lowest grade is granite. However, it is well known that the higher the basic properties of the rock, the easier it is to be oxidized and weathered. Therefore, the saying "easy to grind but difficult to select, easy to select but difficult to grind" makes sense. Generally speaking, rock gold deposits can be divided into quartz vein type, broken zone altered rock type, fine vein impregnation type, and quartz calcite type from the perspective of mineral processing.

1. Quartz vein gold mine: digging gold from waste rock to achieve double benefits.

Quartz vein gold mines use pyrite as the main gold-bearing mineral, and gold is stored in the cracks of the gangue. Traditional flotation needs to process a large amount of quartz gangue, resulting in high costs and waste of resources. The ore color sorter uses the surface characteristics of pure quartz and pyrite-associated quartz ore, and uses photoelectric color sorter technology to sort out pure quartz and gold-bearing pyrite. The selected pure quartz ore can be directly sold as raw material; and the grade of gold-bearing pyrite concentrate can be greatly improved. Taking a vein quartz gold mine in Henan as an example, the amount of ore entering the float is reduced by 40%, and the gold grade is increased by more than 50%.

2. Broken zone altered rock type gold deposit: pre-enrichment reduces tailings risk.

The gangue of the altered gold deposit in the broken zone is mainly quartz and sericite, and the metal minerals are mainly pyrite, which is in the form of fine vein disseminated. Gold and sulfide ores coexist, and the surrounding rock alteration is mainly silicification, kaolin, sericite and carbonate. In addition to pyrite, sulfide ores are easily accompanied by chalcopyrite, galena, sphalerite, etc. This type of deposit is usually easy to select, and a higher recovery rate can be obtained through single flotation. If the weathering is severe, the tailings can be recovered secondary through full mud cyanidation. For low-grade ores in this type of mine, AI photoelectric intelligent sorting equipment is used to identify gold-containing sulfide ores in the associated ores, and low-grade surrounding rocks are discarded to improve the grade of the gold mine and realize the recycling of gold resources.

3. Fine vein impregnation type gold deposits: targeted removal of harmful impurities.

Fine vein impregnation gold deposits are relatively complex, and the most obvious feature is the disseminated output of gold minerals. The metal minerals are complex, including pyrite, arsenopyrite, chalcopyrite, galena, magnetic pyrite, stibnite, etc. Most of the arsenic refractory ores we often talk about belong to this type. Due to the existence form of gold and its subtlety, this mineral is often separated by a combined process to achieve better recovery rate indicators.

4. Quartz-calcite gold deposit: efficient activation of dispersed resources.

The gangue minerals of quartz-calcite gold deposits are quartz and calcite. Gold minerals are soaked in gangue and metal minerals. Metal minerals range from simple to complex. Most of them contain poisonous sand, realgar, magnetic pyrite, black copper ore, etc. Since gold is well distributed, metal minerals have a greater impact on the mineral selection process. Therefore, it is difficult to take into account both sorting efficiency and economy through a single process.The AI sorting machine grabs the surface multi-dimensional characteristics of quartz, calcite and associated minerals (such as spots, color, texture, etc.) for pre-selection. After pre-selection, the concentrate is recovered by flotation, which can greatly reduce the amount of flotation.

III. Technology empowerment: from cost reduction and efficiency improvement to green mines.

The core of MINGDER sorting technology lies in multi-dimensional perception and resource recycling:

Precise sorting: spectral recognition accuracy>99%, can process low-grade ore with a boundary grade of 0.3g/t;

Zero waste goal: quartz, calcite and other gangue stones are turned into treasure, and the amount of tailings is reduced by 50%-70%.

MINGDER technology not only solves the problem of "high cost and low recovery rate" in traditional mineral processing by accurately adapting to different types of rock gold deposits, but also reconstructs the economic model of mines with resource-based thinking. From "waste rock to building materials" of quartz vein mines to "AI pre-enrichment" of complex associated minerals, technological innovation is driving the industry towards efficiency, greenness and sustainability.