Top 10 Gold Mines in the World 2019

According to the report of Global Golden Yearbook 2019, in 2018, the world’s total gold production was 3,503 tons, 61 tons higher than in 2017. The world’s top ten gold mines produced a total of 346.06 tons, accounting for more than 10% of the total.

Where are the top ten gold mines in the world, and its company? Join us to explore the largest canyons excavated by man yet.

1. Muruntau gold mine

Muruntau gold mine

Muruntau is located in the hinterland of the Zilkum Desert in Uzbekistan, owned by the Uzbek government.
It is easily awarded the title of the world’s largest gold mine, producing almost twice as much as the second-ranked mine. However, GFMS pointed out that the mine’s information is not transparent, because the information about the Muruntau mine has long been a state secret.

2. Pueblo Viejo mine

Pueblo Viejo mine

Pueblo Viejo is a mine jointly developed by Barrick Gold and Canadian Gold, with a shareholding ratio of 6:4. The mine is located in the Dominican Republic and its production increased by 22.65% year-on-year in 2017.

3. Goldstrike mine

Goldstrike mine

Goldstrike Gold Mine is one of Barrick Gold’s largest gold mines in Nevada, USA. The mine consists of an open-pit mine and two underground mines. As of December 31, 2017, Goldstrike’s gold reserves were 251.94 tons. In 2018, the mine is expected to produce between 28.3 tons and 29.58 tons at a production cost of $910/oz to $980/oz.

4. Grasberg mine

Grasberg gold mine

Grasberg is a copper-gold mine in Indonesia. The mine is mainly owned by Freeport-McMoRan and the Indonesian government owns approximately 9% of the shares. The mine has been in operation since 1990, but has recently faced some problems: Freeport-McMoRan and the Indonesian government have disputed the terms of the contract, which may result in the looting of thousands of workers.

5. Cortez mine

Cortez gold mine

Cortez is another large mine owned by Barrick Gold, located in Nevada, USA. The gold production of the Cortez gold mine increased by 6.11% year-on-year in 2017, is expected to be between 38.88 tons and 40.12 tons in 2018, and the annual maintenance cost is $430/ounce to $470/ounce. As of December 31, 2017, the mine’s gold resource reserves were 317.26 tons.

6. Lihir mine

Lihir mine

Lihir was acquired by Newcrest Mining in 2010. The mine is located on Lihar Island in Papua New Guinea. Since 1997, the mine has produced 311 tons of gold.

7. Carlin mine

Carlin mine

Carlin is a Newcastle-owned gold mine in New South Wales that includes Phoenix, Long Canyon and Twin Creeks. Mine’s output increased by 6.14% in 2018.

8. Olimpiada mine

Olimpiada mine

Olimpiada is located in Russia and is an open pit mine owned by Polar Gold. The Olympia gold mine began production in 1996 and is the company’s largest gold business. The mine’s gold reserves reached 936.22 tons. In 2018, the mine’s gold production increased by 17.88% year-on-year.

9. Boddington mine

Boddingtonc mine

Boddington is one of Australia’s largest gold mines. The mine was initially owned by three companies (Newmont, Anglo Ashanti and New Jersey) and now wholly owned by Newmont. The Bodington Gold Mine’s 2018 gold production increased by 10.62% year-on-year.

10. Kalgoorlie Super Pit mine

Kalgoorlie Super Pit

Kalgoorlie Super Pit is located in Western Australia and is operated by a joint venture between Barrick and Newmont in a 5:5 ratio. The output of the mine will increase significantly due to the higher ore grade.

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World Top 10 Gold Mining Companies List 2019

Most international mining companies attach great importance to strategic layout. They operate a variety of minerals and resources all over the world. Especially the old brand international gold mining enterprises have experienced hundreds of years and have been developing steadily for a long time.

Join us to explore the world top 10 gold mining companies in 2019.

1. Barrick Gold Corporation

Barrick Gold Corporation is the largest gold mining company in the world, was founded in 1983 by Peter Munk, headquartered in Toronto, Canada.
Barrick Gold is principally engaged in the production and sale of gold and copper, as well as exploration and mining development activities, and its gold exploitation, mineral processing, beneficiation technology is at the forefront of the world. The company is listed on the New York Stock Exchange (codename “NYSE”) and the Toronto Stock Exchange (codename “ABX”).

barrick gold corporation

Main mines and their distribution

Barrick has more than 100 gold mines spread in continents, Canada, the United States, Peru, Argentina, Australia, the Dominican Republic and Papua New Guinea. Recently, Barrick agreed with Chinese mining giant Shandong Gold in an effort to retain its premier status.
barrick gold corporation gold mines distribution

Barrick main gold mines distribution map

There are currently five core mines: Cortez, Goldstrike, Lagunas Norte, Pueblo Viejo and Veladero, about 70% of the gold production in 2018 came from these five core gold mining areas.

barrick gold corporation gold mines distribution yield

Description of Barrick main gold mines

Barrick exploration status

Barrick is committed to continually discovering and replacing assets and resources in search and selective acquisitions. Even in the years when the gold price was low, most companies were in a state of austerity, and the company was fully committed to discovering the Lagunas Norte deposit in Peru, which was the one of the most important gold mines discovery in the 1990s. The recently major discovery is the Kotz mine in Nevada (gold reserves of approximately 283 tons).

Barrick has been focusing on the exploration of Nevada minerals, one of the most stable places in the world, and Barrick has strong control over the minerals in Nevada. In 2014, Barrick’s 50% budget was allocated to the Nevada exploration project, mainly for prospecting exploration of the Goldrush project. In addition to this project, Barrick still has other development opportunities and projects in the vicinity of Nevada, including Kotz and The Goldstrike project, which helps companies overcome risk and adjust capital back.

2. Newmont Mining Corporation

Founded in 1921 and listed in 1925, Newmont is headquartered in Greenwood Village, Colorado. The company has approximately 30,000 employees, most of whom are in the United States, Australia, Ghana, Peru and Suriname. Its operations are mainly in gold, copper, coal, oil and natural gas. In February 2002, it acquired Canada’s Franco-Nevada and Australia’ Normandy. Newmont is a leader in the value creation industry and the only gold producer in the S&P 500.

Newmont Mining Corporation

Main mines and their distribution

Currently, Newmont has more than 40 projects in North America, South America, Oceania, Indonesia, Africa, Asia, and other regions.
Newmont gold mines distribution

Barrick main gold mines distribution map

Newmont Mining Corporation gold mines distribution yield

Newmont exploration status

In 2016, the Newmont has proven and probable gold reserves of 1,942 tons, with a mining area of 59,000 km2. At present, three-quarters of the company’s gold reserves are concentrated in the United States and Australia. Through the drilling survey in Australia alone, has added 116t of gold reserves, especially the Tanami and Merian mines, which have increased by 40t and 17t respectively. The discovery of these high-quality gold ore has raised the average gold grade to 1.2×10-6.

3. Anglogold Ashanti

Founded in 1944, AngloGold Ashanti is the third-largest gold mining company in the world, headquartered in Johannesburg, South Africa. AngloGold Ashanti is a global gold producer, with 17 gold mines in 9 countries and exploration projects in gold production areas around the world, has been listed in the New York, Johannesburg, Accra, London, Australia, and Paris and Brussels stock exchanges.

Anglogold Ashanti

Main mines and their distribution

AngloGold Ashanti’s mining projects are mainly distributed in Africa, Australia and the Americas.

AngloGold Ashanti main gold mines distribution map

AngloGold Ashanti gold mines distribution yield

AngloGold Ashanti exploration status

From 2015 to 2016, the company invested a total of 1.79 million euros in exploration, increasing the amount of mineral resources of 283 tons, produced 3.8 million ounces of gold in 2017. The value of AngloGold Ashanti’s assets is around $9.5 billion.

4. Goldcorp Inc.

Goldcorp Inc. is a gold producer engaged in the trading, exploration, development and acquisition of precious metals in Canada, the United States, Mexico, Central America and South America. Current operating is mainly in the sale of gold, copper and silver.
Goldcorp Inc. was originally established on March 31, 1994, and later acquired Glamis Gold. The merged new company was formally established on December 1, 2006.

Goldcorp Inc. is one of the world’s lowest-cost and fastest-growing gold producers with operations throughout the Americas. Headquartered in Vancouver, British Columbia, Canada, employs more than 15,000 people worldwide.

Goldcorp Inc.

Main mines and their distribution

The main mines of Goldcorp are located in Canada, the United States and Latin America. The Red Lake mining area is located in the world’s brightest gold belt and is one of the highest grade gold mines in the world. HGZ is the core producer of gold in the Red Lake mining area, with an average grade of 56.7×10-6, but it is expected that by 2020, the ore in the plateau mining area will be exhausted.

Goldcorp Inc. is advancing the exploration of two new mining areas, Cochenour and HG Young, which have great potential to become a source of new ore.

Goldcorp Inc. main gold mines distribution map

Goldcorp Inc. exploration status

In the next five years, the company plans to increase its gold production and gold reserves by 20%, while reducing the cost per ounce by 20%. After years of cost reduction, the industry is experiencing a decline in gold production and gold reserves and a possible increase in unit costs.

In 2017, the company’s exploration and development has made great progress, and the Cerro Negro, Silica Cap and Bajo Negro projects have achieved encouraging results, and these projects continue to have new discoveries. The results obtained include gold-bearing ore bodies with a grade of 20.80×10-6 over 5.01m thick (Bajo Negro project, BDD-17006), and gold-bearing ore bodies with a grade of 4.75×10-6 and a thickness exceeding 5.16m thick. (Silica Cap project, SCDD-17003).

5. Kinross Gold Corporation

Kinross Gold headquartered in Canada with mines and projects in Brazil, Canada, Chile, Ghana, Mauritania, Russia and the United States, mainly engaged in gold mining, silver mining, exploration, extraction, processing, etc.
Listed on the Toronto Stock Exchange (code: K) and the New York Stock Exchange (code: KGC).

In 2016, the company produced a total of 79t of gold, which refreshed the company’s production record. Despite the multi-faceted challenges, the company’s operating performance in 2016 remained strong. With the increase in the price of gold, the company’s cash flow exceeded $1 billion and its assets and liabilities performed well.

Kinross Gold Corporation

Main mines and their distribution

The main gold mines are located in the Americas, West Africa and Russia, its proven recoverable reserves are 863.4 million tons. The proportion of resources distribution is 12.5% in North America, 81.99% in South America, and Russia. 0.22%, Africa 5.29%, mostly open-pit mines, and all are wholly-owned or absolutely controlled.

Kinross Gold main gold mines distribution map

Kinross Gold exploration status

Kinross Gold is stepping up its expansion of known mineralized belts, and the Kupor mining area has great potential, drilling procedure has found obvious mineralization in certain areas. In the past few years, the company has taken many measures to promote key projects to extend mine life, maintain quality products, reduce costs and increase cash flow.

6. Newcrest Mining Limited

Headquartered in Melbourne, Australia, Newcrest Mining Limited is the largest gold producer listed on the Australian Stock Exchange (ASX), one of the top 50 listed companies on the Australian Stock Exchange and one of the world’s largest gold producers.

Newcrest Mining Limited

Main mines and their distribution

Newcrest mines are mainly located in Australia, Papua New Guinea, Indonesia and Côte d’Ivoire. Current major businesses include Cadia Hill (New South Wales, Australia), Telfer (Western Australia), Gosowong (Halmahera Island, Indonesia), Lihir Island (New Ireland, Papua New Guinea), and Bonikro (Côte d’Ivoire).

Newcrest Mining Limited main gold mines distribution map

Newcrest Gold exploration status

In the past 15 years, Newcrest has discovered several large deposits.

Newcrest is currently evaluating two major exploration areas in the provinces of Namosi and Papua New Guinea in Fiji. Its joint venture, Namosi, is conducting a survey of Namosi and Natasiri provinces about 30km south of Suva, which covers an area of approximately 724km2. The Golpe exploration project is located in the Mobori province of Papua New Guinea, expected to have a mineral resource of 737t gold and 8.8 million tons. Copper and 1361t of silver.

7. Gold Fields Limited

Gold Fields is a world-renowned gold producer and a major player in gold resources in South Africa, Ghana, Australia and Peru. Principally engaged in underground and surface gold and copper mining and related activities, including exploration, mining, processing, and smelting.
In 2012, Gold Fields established a new company headquartered in South Africa and split its subsidiary, Sibanye Gold, which is 100% owned.

Main mines and their distribution

Gold Fields mines are mainly in Australia, South Africa, the Americas and West Africa, and are mostly open-pit mines, all of which are wholly or wholly owned.

Cerro Corona mine, located on the eastern slope of the western Sierra Mountains in northern Peru, has reserves include 37t gold and 208,800 tons of copper.
Gold Fields has St Ives, Agnew, Darlot, Granny Smith mines, and 50% owned Gruyere in Australia, with a gold resource of 439 tons and a reserve of 164 tons.
The largest mine in South Africa is the South Deep mine, one of the largest gold mines in the world, with a gold resource of 1786 tons and a reserve of 1057 tons.
In addition, Talca and Dama mine in West Africa, Gold Fields own 90% of the shares and the remaining 10% are held by the Ghanaian government.
Gold Fields gold mines distribution

Gold Fields main gold mines distribution map

Gold Fields exploration status

The company has increased its exploration investment year by year. The investment in Australia has increased from US$68.1 million to US$89 million, and the total drilling depth has increased from 617.14 km to 661.36 km.
A major breakthrough was made in the exploration project at Ives and the Granny Smith mine.

8. Polyus Gold

Located in Moscow, Polyus is Russia’s largest gold producer and one of Kazakhstan’s largest metal producers, with gold production ranking among the top ten in the world, has proven gold reserves of 1865t.

Polyus is mainly involved in the eastern Siberian region where is rich in gold, and in some alluvial plains. In addition, it has mining rights or exploration rights for several gold mines in Kazakhstan, Romania and Kyrgyzstan.

Polyus Gold

Main mines and their distribution

Polyus main mines include the Olimpiada, Blagodatnoye, Titimukhta, Verninskoye, Alluvials and Kuranakh mines. The Olimpiada mine is located in Russia’s largest gold mining area and is the company’s largest project. The mine started production in 1996 and currently accounts for more than one-third of the company’s total gold production. In 2015, it produced 21 tons of gold. The exploration work in the area shows that there is huge potential in the vicinity.

The Blagodatnoye mine is about 25km from the Olimpiada mine. It is the company’s second-largest mine and was commissioned in July 2010. It is the largest gold ore processing plant in Russia.

GoPolyus gold corporation gold mines distribution yieldPolyus main gold mines

Polyus exploration status

The Polyus exploration mines are Chertovo Koryto, Panimba and Razdolinskaya, Nezhdaninskoye and Bamskoye.
The Chertovo Koryto mine is about 170km from the Verninskoye mine, located in the southern Siberian gold belt, with a gold resource forecast of 88t.
The Panimba and Razdolinskaya mines are located in the Krasnoyarsk region of eastern Siberia with a gold resource (presumed) of 165t.
The Nezhdaninskoye mine is located in the Vihoyansk Mountains, a preliminary feasibility study report jointly developed by SNC-Lavalin and Gold Fields and AB Global Mining has been submitted and is currently under review.
The Bamskoye mine is part of Nevachanskaya, located in the northern part of the Amur region bordering China with a gold resource of 99t.

9. Sibanye Gold

Sibanye Gold was once a wholly-owned subsidiary of Gold Fields, independently listed in 2013 and is focused on gold mining in South Africa. It currently owns and operates three open-pit gold mines and one underground gold mine in South Africa.

Sibanye gold

Main mines and their distribution

Sibanye Gold mines distribution

Polyus exploration status

In 2013, Sibanye Gold and Gold One International Ltd. entered into an agreement through which the company acquired ownership of the Cooke underground and open-pit mines in West Witwatersrand and bid for a 100% stake in Witwatersrand United Resources Ltd.
Later, acquired Aquarius Platinum Limited (Aquarius) in 2016 and acquired Rustenburg’s platinum assets from Amplats.
In May 2017, Sibanye Gold’s acquisition of Stillwater Mining Company came into effect.
These acquisitions increase the annual gold production of the Sibanye Gold, increase the operational flexibility, and have a great opportunity to bring new blood into the Sibanye Gold company.

10. Harmony Gold

Harmony Gold has more than 60 years of history and is one of the world’s largest gold mining companies. It is the third-largest gold producer in South Africa and employs approximately 30,441 people in South Africa. The company is listed on the Johannesburg and New York Stock Exchange.

Harmony has nine underground mines in South Africa, an open-pit mine and several surface mines, as well as a 50% stake in the Morobe mining joint venture, including the Gorp project. These mines are located in the world-famous Witwatersrand Basin and the Kraaipan Greenstone Belt.

Harmony Gold

Main mines and their distribution

The main gold mines operated by Harmony include the Doornkop, Kusasalethu, Phakisa, Tshepong, Target, Hidden Valley, Kalgold and Unisel mines, which together account for more than half of the company’s total production.
Harmony Gold mines in south Africa

Harmony Gold exploration status

Harmony Gold’s exploration program is mainly in South Africa and Papua New Guinea, focus on discovering large and long-term gold and copper mines. In 2016, $29.9 million was invested in exploration in the Papua New Guinea region.

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Placer Gold Deposit and Mining Beneficiation

Alluvial gold is formed by gravity separation from a specific gold containing rock during the sedimentary process. Thereby, this kind of placer deposit is usually as fine as sand, also called sand gold.

Placer deposit is a significant source of gold, placer mining was the main method used in the early years of many gold rushes, like the California gold rush.

Next, I will do a description of the following aspects:
Go to the What is the placer gold, Types of placer deposit, Placer gold mining flowsheet and equipment.

What is the placer gold

According to mineral morphology, the gold mineral is divided into rock gold and placer gold.

1. Rock gold is the most common form of pure gold. Gold is hidden in the quartz veins in the rock, we need to find the gold-bearing rocks first, then exploit the ore, crush them into ore powder, and then purify them by gravity or flotation.

2. The placer gold is easy to mine. The process of rock gold mining is relatively complicated and difficult. Generally, a ton of ore is mined to extract a few grams of gold.

rock gold and placer gold deposit

The presence of the primary gold-bearing geological body is a prerequisite for the formation of placer gold deposits. These primary gold-bearing geological bodies can be either primary gold ore bodies, gold-bearing altered rock belts, fractured fracture zones, or wide area gold-bearing rock masses rock formations.

A hilly area is a place where gold is concentrated. In the same area, where the gold placer is concentrated where the relative height difference changes from large to small. The gold particles are transported and moved by various natural forces and will be deposited in a favorable geological environment.

The riverbed alluvial deposit is the most important source of gold deposits in gold production. Alluvial deposits are formed by a series of deposition processes. The deposition is a dynamic process, due to the lateral movement of the river channel, the location of the river alluvial gold deposit in the valley is generally not consistent with the current river channel, often occur on the side of a moving curved channel or downstream of a river.

river PLACER-DEPOSIT formation

The confluence of rivers or streams plays an important role in the search for gold deposits, the eddies generated at the confluence enhance the deposition of gold particles.

The distribution of placer gold in the gravel layer is extremely uneven. After a long period of hydraulic erosion, the lighter gold particle is carried away by the flowing water, while the coarse gold with a larger specific gravity and smaller grain size falls into the lower or bottom of the gravel layer along with the pores between the sand particles. In general, gold is enriched in the lower part of the gravel layer, that is, placer gold enriches in the gravel layer about 1 to 2 meters above the bedrock, even enriched on the bottom of the gravel layer.

Types of placer deposit

According to the landform and formation conditions, placer gold can be divided into

  • River gold deposit, in the river bed, bank, or shoal
  • Flood plain gold deposit, mostly large and medium-sized deposits.
  • Terrace gold deposit, in the valley slope terrace area, most of them are the remaining parts of the original floodplain gold deposits that were eroded.
  • Valley gold deposit usually in coarse size, with high grade and low water content, it is a good source of gold production, but a shortage in small scale.
  • Karst gold deposit often produced in karst tunnels and caves.types of PLACER DEPOSIT

The width of gold deposits is generally 50-300m or wider, and the length can reach several kilometers or even tens of kilometers; generally it is made up of soft sandstone; the buried depth of the ore is generally 1-5m, some would 20-30m even deeper; the thickness of the gold-bearing ore layer is usually 1-5m; the bottom of gold layer is mostly granite, shale, limestone.

Associated minerals

In addition to gold, gold deposits also contain a variety of heavy minerals, which associated with gold, magnetite, ilmenite, rutile, garnet, zircon, hematite, chromite, olivine, epidote, pyrite, monazite, limonite, platinum, antimony, cinnabar, wolframite, scheelite, cassiterite, corundum, diamond, mercury paste, galena, etc.

In the placer gold deposit, heavy minerals usually does not exceed 1-3 kg/m3, and the rest are gravel, pebbles, sand and clay. Clay is not good for the fine-grained gold recovery process and should be removed before the gold selection process.
Gold is mostly in the form of granules, flakes and branches in the placer gold deposits, its size generally in the range of 0.2-2mm.


Characteristics of placer gold

1 Low gold content, generally 0.2-0.3g/m3, and the content of heavy mineral (S>4) is usually 1-3kg/cm3.
2 The maximum particle size of gangue ore is often several thousand times larger than the minimum grain size of placer gold. That is to say, raw ore of sand gold is in large size, it is necessary to pick out the gold-free gravel and reduce the size of the ore containing ore.
3 Low production rate
4 High concentration ratio
5 It takes several complicated beneficiation processes to obtain gold and qualified heavy mineral concentrates.

According to the particle size

gold is divided into
1. Large grain gold (greater than 5 mm)
2. Coarse grain gold (1.65 ~ 5 mm)
3. Medium grain gold – 0.83 ~ 1.65 mm
4. fine grain gold – 0.42 ~ 0.83 mm
5. Particulate gold – 0.15 ~ 0.42 mm
6. Floating gold – less than 0.15 mm.

Placer gold mining flowsheet and equipment
Placer gold mining flowsheet and equipment

The beneficiation of placer gold ore is based on the difference in physical properties of minerals, such as the difference in particle size, shape and specific gravity, the gravity separation is the main method of placer alluvial gold beneficiation processing.

Commonly used gravity separation equipment includes chute (sluice), various types of mineral jigs, gold shakers, centrifugal concentrators, etc. Cross-flow belt chutes, short cone hydrocyclones, vibrating chutes, etc., have broad application prospects.

According to the working principles, the gravity separation process can be divided into ore washing, particle grading, gold sluice, gold jig, gold shaker and heavy medium separation. Among them, except for washing and grading, which are mainly separated by particle size, the other is the process of separating the minerals by specific gravity (density).

1.Preparation before beneficiation

The preparation work before the selection mainly includes the disintegration, classification, cleaning and de-sludge of the sand mine.
Disintegration: break the sand mud lump to monomer particle, separate the valuable minerals.
Classification: Separate coarse gravel that does not contain gold and other heavy minerals.

Disintegration and classification operations can be carried out in one equipment as a gold trommel scrubber or a trommel screen, can also be used for washing and deliming.

2.Heavy mineral separation

Remove light minerals and stone remaining in the slurry, then separate other heavy minerals to obtain gold.

Generally, use large size fixed gold sluice to select the coarse gold, and then use gold pan to select the gold concentrate.
In order to improve the gold recovery rate, the roughing operation can also use a gold jig to replace the sluice, and replace the gold pan with a jig and a shaker.

3. Concentration

The commonly used beneficiation equipment are shaker table, jig, mercury amalgamation cylinder, magnetic separator, electric separator, and the like. After these treatments, the gold department was concentrated in the mercury paste.

The typical process of river alluvial gold mining.
alluvial gold processing sheet design

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Related post:
5 Easily Extracted Gold Ores and 8 Processing Methods
Rock gold process

5 Easily Extracted Gold Ores and 8 Processing Methods

Easily extracted gold ore has long been a major source of gold production in countries around the world, and such resources will be declining due to long-term mining.
placer gold ore digging and processing

What is Easily Extracted Gold?

1 Placer gold ore

Placer gold deposits are formed by primary gold deposits broken up by mechanical and chemical weathering and transported, sorted and deposited by external forces. There are many kinds of placer gold deposit, such as eluvial gold deposit, slope gold deposit, diluvial gold deposit, riverbed alluvial gold deposit and shore gold deposit, etc.

The characteristics of this kind of deposit are soft, shallow burial depth, generally 5~10m, some 20~30m; the thickness of gold-bearing deposit is generally 1~5m, individual up to 10m; The belt width is 50~300m on average, and the length can reach several kilometers or tens of kilometers; the slope of the gold deposit is very small, generally 0.002~0.02.

The gold ore is generally simple in composition, shape mostly in granular or scaly, and the particle size is usually 0.5~2mm, average density about 17.5~18.0g/cm3. According to the particle size, gold can be divided into a large piece of gold (greater than 5mm), coarse gold (5~1.65mm), medium gold (1.65~0.83mm), fine gold (0.83~0.42mm), extra fine gold (0.42~). 0.15mm) and the most particulate gold (or floating gold, less than 0.15mm).
easily extracted gold ore and its processing methods

2 Gold-bearing quartz vein ore

The basic composition of ore is quartz, with a content of more than 90%, and almost no heavy metal sulfide. Natural gold is mostly filled in the crack and cleavage surface of quartz in coarse grains, or disseminated in quartz veins in fine grains. Gold is easy to dissociate after crushing and grinding.

3. Gold-bearing quartz vein ore containing a small amount of sulfide

This ore is most common in gold-bearing quartz veins ore and generally contains 1% to 5% of metal sulfides. According to the state of gold production, it can be divided into two types: one is associated with sulphide ore, another is associated with gangue minerals such as quartz.

(1)Associate with sulphide ore
The composition of such ore is relatively simple. Pyrite is the main metal sulfide, and the content of sulfides such as copper, lead, zinc and antimony is very small. The relative content of natural gold in pyrite is more than 60%, and the remaining gold is present in gangue minerals such as quartz and other metal sulfides. This type of ore is most suitable for flotation. For the very fine gold contained in the flotation tailings, tailings cyanidation can be carried out. When the grinding product contains coarse particles of free gold, it should be added with mercury or gravity separation before flotation.

(2) Associate with gangue minerals
The main feature of this ore is that the metal sulfide content is low, and more than 70% of natural gold is symbiotic with quartz. The metal minerals in the ore are mainly pyrite. In addition, there is a small amount of chalcopyrite, pyrrhotite, stibnite, galena, etc., but no arsenic, antimony, clay and carbonaceous materials.
Such ores are more suitable for treatment by the “mercury + cyanide” method or the whole mud cyanidation method.
placer gold alluvial gold ore extraction

4 Quartz vein containing gold oxide ore

Oxidized ores are generally present in the shallower surface oxidation zone. According to the degree of oxidation, it can be divided into partially oxidized ore and oxidized ore. Most of the natural gold is found in gangue minerals and metal oxide minerals. The gold content of the ore is high, mostly between 10 and 20 gt. The surface of the gold particles often has an iron oxide film, and the degree of pollution increases with the increase of the oxidation rate of the ore. The commonly used processing method is “mercury (or gravity separation) and cyanide”, partially oxidized ore can use flotation process.

When the gold practices in the ore are coarse, the surface of the gold particles is clean, and the ore is not muddy, 70%~80% of the gold can be recovered from the ore by using the “single amalgamation” or “mixed mercury gravity separation” process.
When the ore with high oxidation degree, high content of mud, and series surface pollution, even though the particle size is coarse, it is not suitable to be directly treated by amalgamation. It must be gravity separated first, and the heavy sand (concentrate) is selected to be scrubbed by grinding machine to remove the surface contamination, then mix the mercury.
The fine particle ore with a low oxidation degree is usually treated by flotation.
As for the fine particle ore with high oxidation degree, and dispersed in non-sulfide minerals, even if the surface of the gold particles is not contaminated, the gold particles are too fine to be treated by the amalgam method. The only feasible treatment method is the whole mud cyanidation process, the gold leaching rate can reach 96%~98%.

5 Pyrite gold-bearing quartz vein ore

The mineral composition of this type of ore is similar to that of a small amount of sulfide quartz vein ore. The difference is that the sulfide content is high (5% to 15%). Metal minerals include pyrite, pyrrhotite, galena, sphalerite, chalcopyrite, and porphyrite, but pyrite accounts for more than 80%. The gangue minerals are mainly quartz, followed by calcite, feldspar, chlorite, sericite and the like.

Natural gold has a very close relationship with pyrite, so this type of ore is very suitable for flotation treatment, and the recovery rate can reach 93%~96%. If the ore contains coarse particles of free gold, it should be gravity separation before the flotation. When there are refractory gold-containing sulfide mineral particles in the flotation tailings, they can be recovered by the gold shaker.
river gold processing alluvial gold

8 Methods to Extract Gold

The gold beneficiation process of easy to separate gold ore consists of amalgamation, gravity separation, flotation, and cyanide. The choice of the extraction processing method depends on the nature of the ore and the requirements of the product form.
The commonly used beneficiation flow as following.

1 Amalgamation

This procedure is suitable for the quartz primary ore and oxidized ore containing coarse gold. Simple layout, low investment, and fast effect, which is suitable for small gold processing plant.
related post: Gold Extraction Processing and Environment Consideration

2 Amalgamation – gravity separation

Two schemes: first amalgamation and then gravity separation or first gravity separation and then amalgamation. The former one is suited for the treatment of simple gold-bearing quartz vein sulphide ore, amalgamation process can recover the coarse particle-free gold, then gravity separation to select the heavy metal sulfide concentrate containing gold. The latter scheme, first gravity separation and then amalgamation, is suited for those oxidized coarse particle ore, and placer gold ore which with a low grade.

3 Gravity separation ( or amalgamation) – cyanide process

This flow design for gold-bearing quartz vein oxidized ores.
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4 Flotation separation

the flotation process is commonly used to process the gold-bearing quartz vein ore which contains fine particle gold and good flotability sulfide ore, and process gold sulfide ore which contains several valuable metals (such as copper, lead, zinc). The flotation process can enrich gold and other valuable metals to the maximum extent, and waste tailings can be obtained with low production cost.

5 Mercury – flotation combined process

The basic premise of using this process is that the coarse gold in the ore can be recovered by amalgamation. the great feature of this process is that can achieve a higher recovery rate than a single flotation process. In addition to the ore processed by the above flotation process, gold-bearing oxidized ore and ore associated with free gold are suitable.

6 Cyanidation (full mud cyanidation) process

As for such gold ore, in the presence of a fine particle in quartz gangue minerals, which are deeply oxidized and do not contain Cu, As, Sb, Bi and carbonaceous materials, is suited for adopts cyanidation.
Advantages: low cyanide consumption, high leaching rate, high efficiency and easy control.

7 Flotation – cyanide process

This combination is mainly used to process gold-bearing quartz vein ore and quartz-pyrite ore those have close symbiosis relation of sulfide. Compared with the cyanidation process, the flotation – cyanide process has the advantages as following:
does not require a fine ground particle, saving consumption; lesser washing and mixing step; smaller area required, low investment.

8 Flotation – gravity separation

It is mainly based on flotation, and is suitable for the ore that is closely symbiotic with GOL and sulfide, and can only be recovered by smelting. Due to the small amount of non-floating sulphide ore particles (mostly pyrrhotite) in the flotation tailings, it needs to be recovered by using a gold shaker table, spiral chute and cyclone.

In summary, the choice of gold processing flow is closely related to the nature of the ore. For some complex gold-bearing ores, especially refractory polymetallic gold-bearing ores, it is technically necessary to select or develop a combination of the gold processing methods in order to maximize gold recovery and efficiently recover various useful ingredients.
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Gold Extraction Processing and Environment Consideration

Gold exists in a variety of ores with complicated mineralogical properties, so there are many options for ore processing and gold recovery. This paper only deals with some of the processes used in the gold processing plant for the recovery of gold, only apply on the sulphide gold ore which is easy to separate, difficult to leach. However, those of the environmental issues discussed are applicable to the almost gold plant.

The general processing flow of recovering gold from the easy separated, difficult leached sulphide ores is shown below.
Gold Extraction Processing
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Gold extraction processing flow

In this process, the ore is first crushed and ground to specified particle size. The ground ore can be sent directly to extract gold or beneficiated, flotation separation and gravity separation are the most used methods. The obtained concentrate and the tailings are disposed of separately.

For refractory ores, pretreatment is required. In order to release gold from sulfide ore bodies, such as pyrite and arsenopyrite, oxidative pretreatment (such as burning, pressure oxidation or bio-oxidation) is generally employed. The refractory ore can be enriched by flotation before oxidation. The oxidation process produces by-products that must be specialized processed prior to the next step.

The classic method of extracting gold is to first dissolve it with a cyanide solution, then replace the gold with the metal from the gold-containing solution, or adsorb it by the carbon slurry method, and then recover the gold from the carbon. The residual cyanide should be removed before returning or discharging the lean liquid to the environment.

All of the processing operations mentioned above have a potential impact on the environment and must be considered during the working flow design phase. For example, noise, dust, smoke, chemical reagent, liquid, solid waste and so on.

Environment considerations

  1. Crushing and grinding
    The crushing and grinding process of the ore produces noise and dust, which mainly affects the environment of the workplace. Sometimes, a reagent such as cyanide is added to the grinding circuit to promote the dissolution of gold, and the added reagent also has an effect on the working environment.
  2. Gold ore dressing
    In the flotation process, the potential source of environmental impact is mainly chemical reagents, which may affect the field and the surrounding environment. The flotation tailings is related to some of the following issues
    (1) Acidic effluent water
    (2) Soluble metal leakage and surface loss
    (3) Drainage water turbidity
  3. Pretreatment
    Pretreatment of gold ore and concentrate, usually using oxidation to decompose gold-bearing sulfide minerals such as pyrite and arsenopyrite. The oxidation products are treated to comply with environmental protection related to waste disposal regulations. In the case of calcination, the sulfur dioxide and arsenic-containing gases produced by it cannot be directly discharged into the atmosphere.
    These oxidation products can be removed by flotation, and gold tailings or oxidation products need to be transported to a remote site for special disposal.
  4. Extraction of gold
    A common method of gold extraction is to dissolve the gold ore in an alkaline solution of cyanide. In any case, for the environmental protection of the workplace, the storage and disposal of the reagents should be seriously considered. The waste slag after gold extraction can be disposed of together with flotation tailings. These solids may contain some residual leaching agents. Related post: Cyanide Gold Extraction Process
  5. Gold recovery
    recover gold from the cyanide solution, the gold can be adsorbed on the activated carbon during the extraction process (CIL) or after the extraction (CIP) or replaced with metal zinc in the displacement precipitation system.
    the gold can be adsorbed on the activated carbon during the extraction process (CIL) or after the extraction (CIP) or replaced with metal zinc in the displacement precipitation system.
  6. Tailings disposal
    There are many options for tailings disposal, such as sealing ponds, decanting ponds, discharging into beaches and lakes, ground deposit, marine disposal, backfilling, dry landfills, etc. This is related to the choice of the best disposal method and the site holding point, and also depends on the distance from the residential area, terrain, hydrology, local regulations, tailings characteristics and real estate management policies.
  7. Reagent transport and storage
    Reagent transport and storage is an important consideration in any study and should be addressed during the metallurgical process design phase. The transportation and storage of reagents, as well as contingency plans, should be considered in detail.

JXSC, a gold mining machine manufacturer, has been supplying gold processing plant equipment and solutions for more than 35 years, always growing and improving in the knowledge and experience among river gold, alluvial gold, sand gold, placer gold, and other minerals.