gold

Extracting Tungsten from Wolframite Gold Ore

The present great demand for tungsten due to world conditions has resulted in an increase of tungsten ore dressing problems for our metallurgists. The flowsheet study shown here was recently developed for treatment of a very complex tungsten-gold ore.

The flowsheet study previously shown for tungsten was devised for a simple tungsten ore free of other heavy minerals. The first consideration of any tungsten ore is to recover the mineral as coarse as possible and avoid sliming and overgrinding by stage crushing and grinding. This is necessary because of the friable nature of all tungsten minerals. This fact was kept in mind for the study shown here, but the problem was complicated due to the occurrence of iron sulphides and free gold with Scheelite.

Straight gravity concentration of this ore, using the flowsheet shown, would result in a mixed gold-tungsten concentrate containing much sulphide which is not desirable for marketing. Consequently, it is evident that other concentration processes must be incorporated in the flowsheet to produce separate marketable concentrates of tungsten and gold. There are numerous possibilities that could be applicable to this problem, but the described flowsheet offered the greatest degree of flexibility.Flotation-Gravity Recovery of <a href=….Read more

How to Process Copper Lead Zinc Ore with Gold and Silver by Flotation

The flowsheet in this study was designed to treat 500 tons per day of a complex base metal ore containing gold and silver values. The presence of free gold offers opportunity to recover these values in the grinding circuit so that the gold could be amalgamated, and marketed directly to the mint. The ore as mined is very wet and sticky and presents certain handling problems.

The Lead Zinc Copper Flotation and Separation Circuit

Lead-Zinc-Copper-Gold and Silver Flowsheet

Every effort is made to recover the minerals as soon as free. Over-grinding causes slime losses which are both unnecessary and costly. The flowsheet is designed for a compact mill of a size that provides economical treatment at this tonnage.

Crushing Plant

The wet ore is delivered to the coarse ore bin directly from the mine and dumped through a grizzly to prevent any large rocks from lodging in the bin and causing subsequent problems in feeding the crusher. The stored coarse ore is crushed in two stages to produce a ¾-inch product. The reciprocating feeder, overhead eccentric-type jaw crusher, and oversize vibrating screen were selected to alleviate problems in handling a wet and sticky ore. All chutes and transfer points ….Read more

Gold and Silver Leaching by Cyanidation

Introduction to Gold and Silver Leaching

The cyanide leaching process is the most important method ever developed for extracting gold from its ores. The early development of the process is attributed to a Scotchman, John Stewart Mac Arthur, in collaboration with the Forrest brothers. The method was introduced into South Africa in 1890. From there it spread to Australia, Mexico and the United States. Now it is used in practically all the major gold mining camps of the world.

The reasons for its widespread acceptance are economic as well as metallurgical. It usually obtains a higher recovery of gold than plate amalgamation and is easier to operate than the chlorine or bromine process. It produces the final product in the form of practically pure metal. Thus the production from a large cyanide mill will be represented by a comparatively small gold bar, which is easy to transport. Accordingly gold mines can be located in relatively inaccessible districts served only by aeroplane or mule train.

However, the gold metallurgist must be familiar with the other processes of gold treatment, such as amalgamation and flotation, as they are frequently used as an auxiliary to the cyanide process.

General Precious Metal Leaching Theory

Before going into the theory ….Read more

Illegal gold miner rescued after 13 days lost at Corcovado National Park

800px-Corcovado_Strand_Nationalpark Corcovado National Park

An illegal miner was found in the Osa Peninsula’s Corcovado National Park, in Costa Rica, where he got lost almost two weeks ago.

Joel Cerdas Solórzano, locally known as “Pizote the gold miner”, went missing on January 23 while illegally mining gold inside the boundaries of the park.

Three days later, a rescue team composed of officials from the National System of Conservation Areas (SINAC) headed into the park.

However, the authorities took a few days until they were then able to find the man, who was dehydrated and disoriented.

TicoTimes.net reports that Cerdas told his rescuers he had not eaten anything for 13 days before being rescued.

Mining process based on bacterias unlocks gold in South Africa

1 PanAfricanResources.com

A bacteria-rich process currently being used in Barberton, a town in the Mpumalanga province of South Africa, can help liberate ultra-fine gold locked in sulphide crystals. The experiment, called Biox technology, is happening in three mines owned by Pan African Resources.

Besides these three pits, there are other five gold mines around the world currently using the biological oxidation process based on dozen different types of bacteria. However, at Barberton, one strain has become dominant because of the ideal conditions, BDlive reports.

The Biox technology has proven to be an extremely clever yet simple technique to unlock gold and other metals tied up in sulphide deposits. When compared to ore treatment with cyanide, the bacterias’ recovery rate is 97 percent against only 40 percent.

gold PanAfricanResources.com

The bacterial hub is kept at 42°C and fed with a bug-rich soup stuffed with air and nutrients, allowing the bacteria to expose the gold before the solution is passed into a traditional recovery process using cyanide and carbon.

This means the bacteria are able to ….Read more

Yamana Gold’s Cerro Moro Mine by Numbers [infographic]

Despite the fact that the mining industry is living dark times, especially due to the downfall of gold’s price, the company Yamana Gold is definitely developing its Cerro Moro gold and silver project.

The deposit, located in the southern Argentine province of Santa Cruz, will move forward thanks to an initial investment of $450 million. However, this is not the only interesting number you can find out about Cerro Moro. Check this new infographic brought to you by Mining Examiner.

CerroMoroMine

Top five countries that lost most gold in 2013

Each country’s central bank is usually known to hold gold reserves that basically just sit in vaults for years. However, the amount of gold each nation possesses represents, in most cases, a big part of its fortune. 

The United States, for instance, has more than 8,000 tonnes of gold.

But 2013 was tough for some countries and not every one of them managed to keep their gold reserves safe and sound. Especially because, this year, gold actually lost about 28 percent of its value, reducing the value of foreign reserves. Based on these numbers, here’s a list of the year’s biggest losers.

1. Portugal

1

  • In 2012, 90 percent of the country’s foreign reserves were in gold.

2013: the country lost about 25 percent of the value of its foreign reserves as the gold price tumbled, the equivalent to $8 billion.

2. Greece

2

  • Greece had 83 percent of its foreign reserves in gold.

2013: the country’s account lost 23 percent of its value.

3. United States

3

Children in the Philippines are damaging their health while mining for gold

399px-thumbnailThere are currently 115 million children with ages from five to 17 years old who work in hazardous occupations worldwide, the United Nations International Labor Organization estimates. Among them, about a million children work in the mining industry. Hundreds of maybe even thousands of them live in the Philippines.

Recently, the Center for Investigative Reporting, in collaboration with the Pulitzer Center on Crisis Reporting, published an article about this scourge through the site Philly.com. The piece started by telling the story of a young miner:

Romnick Bocejo picked up his blowtorch and blasted a small lump of mercury and gold. A cloud of toxic fumes rose around his head as the heat vaporized the mercury. He covered his mouth and nose with his T-shirt, and kept working.

At 16, Bocejo has worked half his life in the meager family business: looking for gold in the remote mining region of Camarines Norte, about 200 miles southeast of Manila.

One of his jobs is to burn the mercury, and on this occasion, he produced a button-size lump of nearly pure gold. He is uncertain whether to believe the smoke is dangerous.

….Read more

Gold: the ultimate store of value [infographic]

Gold has been going through a tough time with the downfall of its price, but that doesn’t make it any less valuable. Actually, gold is still the commodity that helps us define the value of things, despite the fact that it is extremely rare. Did you know that? Maybe not… And there are probably a lot of other facts about gold you ignore.

Luckily for you, here’s an updated infographic about this precious metal, ready to teach you all you need to know.

gold-investment-strategies_52b905798161c_w587

Infographic by Visual.ly via Mining.com

Global gold mine and deposit rankings 2013 [infographic]

Now that we are near the end of 2013, it’s worth to go back with the help of this complete infographic and find out more about the world’s gold mines and deposits. This following list of information shows you all you need to know about exiting and future gold supply.

global-gold-mine-and-deposit-rankings-2013_52931bf77da2f

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