The world Top Ten Gold Miners (tonnes)

     Mining industry exists in many countries. While exploration and mining can be conducted by individual entrepreneurs or small businesses, most modern-day mines are large enterprises requiring large amounts of capital to establish. 'mining industry' is actually two sectors, one specializing in exploration for new resources and the other in mining those resources. The exploration sector is typically made up of individuals and small mineral resource companies, called "juniors", which are dependent on venture capital. The mining sector is made up of large multinational companies that are sustained by production from their mining operations. Various other industries such as equipment manufacture, environmental testing, and metallurgy analysis rely on, and support, the mining industry throughout the world. 

   There are different methods by which gold mining companies are ranked. One is by their annual production. Another is by their cash cost per ounce, that is, how much money it costs them to mine the gold. Since gold prices are the same everywhere, companies with lower costs per ounce make more profit. The most common method lists by market capitalization which considers the total value of capital holdings by that company. Also considered when comparing companies is their market capitalization per ounce of gold equivalent (sometimes abbreviated MV-GEO, EVO if the enterprise value is used) which takes the market value and total reserves and resources for each company as well as the price of gold into consideration.

     With GFMS now reckoning that the pent-up growth in global gold output may well have peaked last year with the various big, and small, new gold projects in the pipeline having mostly now reached full capacity, we could well see some further production downturns from some of the big miners this year, although their financial positions could be improving regardless given the recent concentration on cutting all-in costs – aided in many cases over the past year by the big fall in oil prices and the strength of the U.S. dollar.

Among the top producing companies, there have been some substantial gold output drops from the biggest miners, mainly due to divestments and closures – see table below.

Here is the list of the world Top Ten Gold Miners  2013 / 2014 (tonnes) 
( Source GFMS )

RANK	COMPANY	OUT PUT 2013	OUT PUT 2014	CHANGE Y/Y
1	Barrick Gold	222.9	194.4	- 13%
2	Newmont	157.5	151.2	- 4%
3	AngloGold	127.7	136.9	+ 7%
4	Goldcorp	82.9	89.3	+ 8%
5	Kinross	77.7	80.4	+ 3%
6	Navoi (Uzbek)	70.5	73.0	+ 4%
7	Newcrest	73.5	72.0	- 2%
8	Gold Fields	58.1	62.6	+ 8%
9	Polyus Gold	51.3	50.8	- 1%
10	Sibanye Gold	44.5	50.1	+ 13%

1. Barrick Gold Mining

     Barrick Gold Corporation is the largest gold mining company in the world, with its headquarters in Toronto, Ontario, Canada. Barrick is currently undertaking mining projects in Argentina, Australia, Canada, Chile, the Dominican Republic, Papua New Guinea, Peru, Saudi Arabia, the United States and Zambia.

2. Newmont Mining

      Newmont Mining Corporation, based in Greenwood Village, Colorado, USA, is one of the world's largest producers of gold, with active mines in Nevada, Indonesia, Australia, New Zealand, Ghana and Peru. Holdings include Santa Fe Gold, Battle Mountain Gold, Normandy Mining, Franco-Nevada Corp and Fronteer Gold. Newmont also has many joint venture relationships. As of the third quarter of 2014, Newmont was the world's second-largest producer of gold, behind only Barrick Gold 

3. Anglogold 

       Anglogold was the world's third-largest producer of gold, behind Barrick Gold and Newmont Mining. AngloGold Ashanti Limited is a global gold mining company. It was formed in 2004 by the merger of AngloGold and the Ashanti Goldfields Corporation. AngloGold Ashanti Limited is now a global gold producer with 21 operations on four continents. The company is listed on the New York, Johannesburg, Accra, London and Australian stock exchanges, as well as the Paris and Brussels bourses.

4. Goldcorp Mining

      Goldcorp is a gold producer headquartered in Vancouver, British Columbia, Canada. The company employs about 11 300 people worldwide,engaged in gold mining and related activities including exploration, extraction, processing and reclamation. Goldcorp’s operating assets include five mines in Canada and the U.S., three mines in Mexico, and two in Central and South America. As of the third quarter of 2014, Goldcorp was the world's fourth-largest producer of gold.

5. Kinross Gold Mine

      Kinross Gold Corporation the Canadian-based gold mining company with mines and projects in the United States, Brazil, Chile, Russia, Ghana and Mauritania. Kinross began from the amalgamation of three companies in 1993, initially owning a mine in British Columbia and royalties on a mine in Nevada. Following a series of take overs and mergers, Kinross owns ten active gold mines on four continents

6. Navoi Mining 

       Navoi Mining & Metallurgy Combinat JSC engages in the mining and processing of gold and uranium in Uzbekistan. Navoi Mining  is one of the largest Uzbek companies involved in the mining industry being among the top ten largest uranium and gold producers in the world. The most important ore deposits of the company are located in the Kyzyl Kum Desert.

7. Newcrest Mining 

     Newcrest Mining Limited is an Australian-based corporation which engages in the exploration, development, mining and sale of gold and gold-copper concentrate. It is Australia's leading gold mining company and its operations have expanded beyond Australia, for example Indonesia, thus becoming a prominent international mining corporation. Newcrest’s primary gold and copper production in Australia is at Ridgeway (Cadia Valley Operations), Telfer, Cadia and Cracow and in Indonesia at Gosowong.Past and present exploration was done in the Americas, Asia and Europe. As of the third quarter of 2014, Newcrest was the world's sixth-largest producer of gold.

8. Gold Fields Mine

      Gold Fields Limited is a South African gold mining firm, one of the world’s largest, which is listed on both the Johannesburg Stock Exchange (JSE) and the New York Stock Exchange (NYSE). The company is headquartered in Johannesburg, South Africa. It owns and operates mines in South Africa, Ghana, Australia and Peru. The firm was formed in 1998 with the amalgamation of the gold assets of Gold Fields of South Africa Limited and Gencor Limited.

9. Polyus Gold Mine

       Polyus Gold International is the largest gold producer in Russia and one of the top 10 gold miners globally by ounces produced . The company holds over 90 million ounces of gold reserves . The company's principal operations are located in Russia’s most prolific gold mining provinces in Eastern Siberia and the Far East and include 5 operating mines, alluvial operations and several advanced development projects.

10. Sibanye Gold Mining

       Sibanye Gold Limited is a proudly South African gold mining company with three principal operations, namely Kloof and Driefontein in the West Witwatersrand region and Beatrix in the Free State. Sibanye Gold is the largest producer of gold in South Africa and amongst the top ten largest gold producers globally.

The Biggest Gold Nugget In The World

         A gold nugget is a naturally occurring piece of native gold. Watercourses often concentrate nuggets and finer gold in deposits placers. Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered. Nuggets are also found in the tailings piles of mining operations. Gold nuggets are usually 20.5K to 22K purity (83% to 92%). Gold nuggets in Australia often are 23K or slightly higher, while Alaskan nuggets are usually at the lower end of the spectrum. Purity can be roughly assessed by the nugget color, the richer and deeper the orange-yellow the higher the gold content. The common impurities are silver and copper, and nuggets high in silver content constitute the alloy

     While nuggets have been found on many goldfields around the world, those from Victoria were particularly large and abundant. From the time of the first goldrushes in the early 1850s, No one knows how many nuggets were found. During the late 1800s, the Mines Department compiled an official list of discoveries and also made models of some of the large nuggets. By the time the reporting system ceased in about 1910, 1300 nuggets over 20 ounces had been recorded. However, almost certainly many more nuggets were found than were recorded, as many discoverers avoided publicity for fear of being robbed. None of the large nuggets found during the goldrushes survived, as all were quickly melted down.

Here is an discovery The biggest gold nugget in the world :

1.  Welcome Stranger Nugget

         The world's largest nugget was found just a couple of inches below the ground near Dunolly, Victoria, Australia on 5 February 1869. Welcome Stranger nugget weighing in at 2,315.5 troy ounces (72.02 kg) The Stranger gold nugget was discovered by John Deason and Richard Oates just 2 inches below the surface near a root of a tree in Bulldog Gully. Due to the size of the nugget it could not be weighed on any scales at the time and had to be broken down into 3 smaller pieces. And then the nugget was soon melted down into ingots and shipped to the Bank of England. In this 1869 illustration published shortly after the discovery, the size of the nugget (61 by 31 cm or 24 by 12 in.) is compared to a 12 inch (30 cm) scale bar. Before 1990, just about all large nuggets were melted down for their monetary value. Today there are less than a dozen known nuggets over 500 ounces. One replica of the "Welcome Stranger" nugget can be found at the City Museum in Treasury Place, in Melbourne, Victoria. The other replica is owned by descendants of John Deason.

2.  Welcome Nugget

      The Welcome Nugget was the name given to a large gold nugget, weighing 2,217 troy ounces 16 pennyweight. (68.98 kg) The original 'Welcome Nugget' was discovered on 9 June 1858 by a group of miners in the Ballart gold fields in Victoria, Australia . At the time it was the largest single piece of natural gold ever found. A little over a year later, the nugget was melted down by the London mint to make gold coins, but models were made beforehand to create replicas like the one seen here. At around 2,217 troy ounces (69 kg), it remains the second largest gold nugget ever found. Because of their scarcity, large nuggets always fetch a price well above their value as precious metal. In 2013, the Welcome Nugget's gold content alone would be valued at nearly $4 million, but an actual specimen of this size and purity would sell for many times this amount. Models of the Welcome Nugget were made and distributed to the Geological and Mining Museum in the Rocks in Sydney, and the Museum of Victoria, as well as the Powerhouse Museum, who purchased models of the Welcome Nugget. Models are also a feature of two displays in Ballarat, the Pioneer Miners (Gold) Monument on the corner of Sturt and Albert Streets in Ballarat Central and at The Gold Museum opposite Sovereign Hill at Golden Point. In the United States, a Replica of the "Welcome Nugget" is exhibited in the Mineralogical Museum at Harvard University in Cambridge, Massachusetts.

3.  Pepita Canaa Nugget

       The Canaã nugget, also known as the Pepita Canaa, was found on Sept 13, 1983 by miners at the Serra Pelada Mine in the State of Para, Brazil. Weighing 60.82 kilograms (134.1 lb; 2,145 oz), it is among the largest gold nuggets ever found,and is, today, the largest in existence. The main controversy regarding this nugget is that the excavation reports suggest that the existing nugget was originally part of a nugget weighing 5,291.09 ounces (150 kg; 331 lb) that broke during excavations. The Canaã nugget is displayed at the Banco Central Museum in Brazil along with the second and third largest nuggets remaining in existence, weighing respectively 1,506.2 ounces (42.70 kg; 94.14 lb) and 1,393.3 ounces (39.50 kg; 87.08 lb), which were also found at the Serra Pelada region.

4.   Blanche Barkly Gold Nugget 

The Blanche Barkly gold nugget discovered In August 1857, by Robert , James Ambrose , Samuel and Charles Napier and this gold nugget , weighing in at 1,743 oz ( 49.41 kilograms ) . The Blanche Barkley nugget was found at a depth of 13 feet, and within 5 feet or 6 feet of holes that were dug three years before.

5.  Precious Gold Nugget

       Precious gold nugget discovered 5 january 1871, by Ah chang and party , this gold nugget weighing in at 1,717 oz ( 48.67 kilograms ) . The 'Precious' nugget was originally obtained at Catto's Paddock, Berlin (now Rheola), west of Bendigo in Victoria. Depth from the surface, 12 feet. Gross weight, 1717 03. Approx. value, 6868 sterling pounds.

6.  Canadian Gold Nugget

Gold was first discovered in Ballarat on the rise above Canadian Creek at the base of Poverty Point aka Golden Point in late August (21-24th) 1851. Reports in the Geelong Advertiser instigated the first rush to the Ballarat Diggings. The Gold Commissioner exercised authority over the newly arrived diggers and friction over mining licences and policing rankled many miners, especially those who could not afford the fee. Canadian gold nugget discovered 31 january 1853 in Canadian Gully , by D, and J. Evans, J, Lees, W. Poulter and W.F.Green , this gold nugget weighing in at 1,319 oz ( 37.39 kilograms ) . Canadian gold nugget was found at a depth of 55 to 60 feet (17 to 18 m).

7.  Lady Hontham Gold Nugget

Lady Hontham weighs 1,177 oz (33.66 kilograms ). and that the nugget had been found by Mc Donald, Irwin, Cock , Radcliffe, McPhillamy, Day, Lyons and Bryant. 8 September 1854. A nugget only 8 dwt. lighter than the last-named (which was known as the Lady Hotham) was discovered in Canadian Gully, Ballarat, at a depth of 60 feet, amongst quartz boulders and wash dirt going an ounce to the ton.

8.  Great Triangle ( aka The Big Triangle ) 

        Great Triangle ( aka The Big Triangle ) which is the largest gold nugget weighs 1,157.6 oz ( 36 kilograms ). Chief Curator Gapanyuk specified that the nugget had been found by one Nikofor Syutkin, a prospector. The nugget was found in 1842 at Tsarevo-Alexandrovsky placer in the Urals location in Ural Mountains. Great Triangle gold nugget its shape approaching the rectangular triangle with the size of the other two sides 27.5 and 31 cm. Nugget thickness of an average of 8 cm is a more or less flat, complex shape of the rock crystal gold.

9.  Golden Eagle Nugget

Golden Eagle nugget weighing in at 1136 oz., found by sixteen year old Jack Larcombe on January 8th, 1931 in Larkinville, Western Australia. The nugget required two men to lift it and was given the name Golden Eagle gold nugget due to its resemblance to a bird.

10.  Sarah Sands Gold Nugget

"The Sarah Sands" nugget was also found at Canadian Gully, Ballarat on the 20th January 1853. It was at a depth of 60 feet and weighed 1,117 oz (31,66 kg). It was associated with quartz. Sarah Sands gold nugget discovered by J.W. Gough, F.J.Sulley and J. Bristow

Gold Processing With Method Carbon In Pulp

        Gold processing methods with the Carbon in pulp are often used in large-scale gold mining processing, where the active carbon in pulp method used for recovery of gold ore minerals in the washing tank. Tanks that are used are usually equipped with an agitator and air bubbles equipment and tools are designed to maintain solids in suspension in the slurry, and the achievement of leaching. In the process adsorption ore minerals in the soil material condition of the tank should be good enough to form a slurry that can flow under gravity or when pumped. To form a slurry, mineral ore in the mix with water and the reagent was added to the tank to get the gold leaching reaction

How to work the gold extraction process with carbon adsorption in the pulp can be explained by the following system

Operating A Mine And Ore Processing Newmont Mine

       The first part of the mining process involves finding the minerals and collected core samples from various depths. The core samples were assayed (tested) to determine the mineral content. Material mined from the open pit or from underground is either ore (containing gold and silver) or waste rock (little or no gold and silver). To find out which is which, samples of rock are collected. The samples are sent to an assay laboratory where the rock is tested for its gold content. Geologists use the results to mark out the sampled areas into zones of ore and waste rock so they can be mined separately. Research of a different sort followed; investigation and monitoring was carried out to assess potential environmental and social effects of a mining operation Newmont has both operational and closed tailings impoundments in a variety of climatic and topographic settings. 

      Newmont Mining Corporation, based in Greenwood Village, Colorado, USA, is one of the world's largest producers of gold, with active mines in Nevada, Indonesia, Australia, New Zealand, Ghana and Peru. Holdings include Santa Fe Gold, Battle Mountain Gold, Normandy Mining, Franco-Nevada Corp and Fronteer Gold. Newmont conducts extensive siting, engineering, environmental and social studies to support the specific selection and design of each facility. In 2013, Newmont managed the safe handling and disposal of 173 million tonnes of tailings that consisted of 142.1 million tonnes placed within surface facilities or used for backfilling of pits. An additional 31.9 million tonnes of tailings were deposited offshore in a deep sea canyon

There are two types of mineral mining designs for operating a mine from newmont mine :

•  Surface (open pit) and 
• Underground. Surface

1. Surface (open pit)  

       

    Surface mines are generally preferred if the ore body is relatively shallow and uniform, and are made by digging into the Earth’s surface one layer at a time. The final mine is cone-shaped.First, drilling holes in the ground and fill them with explosive. After the rock has been broken up by blasting, it is loaded into giant haul trucks using large shovels and front-end loaders. Each truck used in the open pit can carry about 90 - 100 tonnes of rock. The rock is hauled to the primary crushers. Rock containing gold, copper and other valuable minerals is hauled away for processing and waste rock is taken to a separate area for storage. Areas of waste rock are later rehabilitated.

      As dig farther down, it is necessary to dewater the mine to ensure that the water level remains below the pit floor. Each day, pump thousands of gallons of water from the pit. Some of this water is used on site to wash vehicles and to spray the haul roads to dampen dust. Excess water is piped over to the water treatment plant near the processing plant to be treated before it is discharged to nearby rivers or lakes.

 2. Underground 

      

       Underground mines are used to extract minerals or metals from deep in the Earth. When building an underground mine, dig a tunnel to get to the minerals, this can be a straight vertical tunnel called a shaft or a tunnel that spirals gradually downwards, called a decline. To access the ore from the shaft or decline, dig other tunnels. also mine out tunnels to provide proper ventilation and emergency exits. mine the tunnels and the ore bodies by drilling and blasting. The broken-up ore is then transported to the surface for processing. Waste rock may be transported to the surface or left in the mine and used to fill empty space.The type of ground support needed depends on how stable the ground is and how long the tunnel is going to be used for. These factors are identified in advance so that engineers can design the mine for maximum safety and value.

      

Ground support may be provided by rock bolts or split sets, which are forced into drilled holes to exert pressure on the surrounding rock, which keeps it intact. Chemicals or grouts are sometimes added with rock bolts to give them greater strength and install wire mesh to keep smaller rocks from falling down.High-pressure spraying of Shotcrete (a mortar/concrete mix) onto the tunnels’ walls and backs provides more support. As complete mining in each stope, backfill it with a cement mixture as well.Underground mines pose a greater safety risk and limit the size of equipment that can be used; however, they cause less environmental disturbance.

Ore Processing Newmont Mine

Basic Ore Processing 

Haul trucks transport the ore from open pits or underground operations to processing operations. Some ores may be stockpiled for later processing. Rock that is not economical to mine is stored in waste rock storage areas. The grade and type of ore determine the processing method used. Additionally, the geochemical makeup of the ore, including its hardness, sulfur content, carbon content and other minerals found within, impact the cost and methods used to extract gold.

Processing methods 
In mineral processing, newmont depending on the mineral ore, they process it using the following methods:

Removing the gold-bearing rock from the ground is just the first step. To isolate pure gold, mining companies use a complex extraction process. The first step in this process is breaking down large chunks of rock into smaller pieces. At a mill, large machines known as crushers reduce the ore to pieces no larger than road gravel.

The gravel-like material then enters rotating drums filled with steel balls. In these drums, feed ore into a series of crushers and grinding mills to reduce the size of the ore particles and expose the mineral.

Next, mill operators thicken the slurry with water to form pulp and run the pulp through a series of leaching tanks. Leaching dissolves the gold out of the ore using a chemical solvent. The most common solvent is cyanide, which must be combined with oxygen in a process known as carbon-in-pulp. As the cyanide and oxygen react chemically, gold in the pulp dissolves. When workers introduce small carbon grains to the tank, the gold adheres to the carbon. Filtering the pulp through screens separates the gold-bearing carbon.

The carbon moves to a stripping vessel where a hot caustic solution separates the gold from the carbon. Another set of screens filters out the carbon grains, which can be recycled for future processing. Finally, the gold-bearing solution is ready for electrowinning, which recovers the gold from the leaching chemicals. In electrowinning, operators pour the gold-bearing solution into a special container known as a cell. Positive and negative terminals in the cell deliver a strong electric current to the solution. This causes gold to collect on the negative terminals.

Alternative Ore Processing

Newmont mine use alternative gold recovery methods in some processing plants to accommodate different ore characteristics or other requirements. For example, ore that has a high level of sulfide minerals or carbon (or both) is called refractory ore. Refractory ore resists normal processing methods as the high sulfide minerals trap gold particles, making it difficult for the cyanide to reach the gold and leach it.

Heating

To leach gold from refractory ore, it must be subjected to high temperature, high pressure and/or oxygen. Newmont treats refractory ore in two ways: by using an autoclave or a roaster.

An autoclave is used before leaching occurs. First, the slurry is heated and fed into an autoclave, where high-pressure steam, water and oxygen are applied to oxidize the sulfide material by a chemical reaction. The slurry is then cooled and sent back into the process to be leached.

An alternative to an autoclave is a roaster, a very high temperature oven that is often used instead of an autoclave if the ore to process contains a large amount of organic carbon. Roasting uses heat and air to burn the organic carbon into fuel and to burn the sulfur off ore, which heat to 932 to 1,202 degrees F. 

Heap leaching

In heap leaching, newmont mine dump crushed ore into piles called heaps, to which apply a weak cyanide solution, using drip feeders. The gold dissolves into the cyanide solution. The entire heap leach area is lined with heavy duty liners to ensure no solution leaks into the environment. Next, collect the gold-cyanide solution in ditches and ponds, and then transport it to a recovery plant.

 
Flotation 

Flotation is a method of separating minerals depending on their ability to attach to air bubbles. Flotation can be used for a number of materials by adjusting the chemicals. At Newmont, it is used for copper recovery and, in a very limited number of cases, for gold processing. 

introduce air bubbles to the slurry while it is in small tanks, called flotation cells. With add some chemicals to the slurry to assist the process. The desired minerals stick to the bubbles and rise to the top, resulting in froth. The froth overflows from the tank, and is removed and sent to the next step in processing.

Gravity circuit

A gravity circuit recovers coarse gold before it is leached. Gravity circuits use the same principles as gold panning: coarse gold is heavier than other material and will settle to the bottom so that it can be removed (gold is 19.3 times heavier than an equal volume of water).

How Newmont mine exploration team discovered a new mineral

         So how do exploration newmont mine teams locate future large-scale projects for a discovered a new mineral ?

       Finding new mineral reserves is critical to the success of company. Locating, extracting and processing these natural resources is a multiyear process that involves complex scientific, environmental and social planning. Searching for gold is a complex, scientific and time-intensive process. With odds of only one in 3,000 discoveries leading to mine development, and only 10 percent of the world’s gold deposits containing enough gold to mine, exploration can be wearisome and expensive. While gold is found throughout the world at concentrations of between two and four parts per billion, need to discover areas that contain 2,000 to 3,000 parts per billion to be profitable. 

       The first step is finding mineral prospecting. With search gold veins typically spanning just a few feet in width, and curving along the Earth’s geography, it is extremely difficult to pinpoint an area of exploration among thousands of square miles of land. Obviously, it makes sense to start in areas known to contain gold, but there are nearly 900 such locations in the world to choose from. Ideally, it is best to start looking in areas less explored first.

Newmont uses several methods to reduce the size of land to explore:

• Evaluate the land geology 
• Analyze the geochemistry of soil sediment and water 
• Commission airborne geophysics surveys to record the level of electrical and magnetic current in the crust below.

       Once a target area has been identified, and geological, geophysical and geochemical data indicate a high probability of a deposit, drilling is conducted. Drilling helps evaluate the type and grade of minerals in the ore. But how many samples are needed? In what direction? How far apart? How deep? Because per-foot drilling costs are expensive, these decisions must be made carefully. Another way newmont mining sample is through trenching, which hugs the surface and is carried out by backhoes or bulldozers. As crews drill, they mark the exact location and depth of each sample taken. Samples are then sent to an accredited lab, which identifies the type of minerals and grade of gold within them. Once information is back from the lab, supplement those findings with geologic, geochemical and geophysical data. Understanding the local geology is a very important part of the process, both economically and environmentally. The geology affects mining, processing and the ways in which manage waste rock, tailings and water. It is also an important aspect of rehabilitation plans.

    Production geologists use information they obtain from sampling, testing, mapping and observation to determine the most efficient and effective mining techniques, as well as to identify the grade (amount of mineral) in the ore. In gold and silver mining, grade is reported as grams per ton. Copper grade is reported as a percentage. It is important to know the grade to determine which rock is sent to the plant for processing and which rock is sent to the waste rock storage area. By using this data and complex computer programs to more accurately define the orebody, mine engineers can determine mining methods, design blast patterns, design dig patterns, and maximize the safety and efficiency of production – as well as determine how the ore should be processed. Geologists also use drilling and sampling data to identify wet areas. Water can cause major problems in both open pit and underground mines. If areas of high water content can be avoided or planned for in advance, can reduce safety risks, costs and production interruptions.