Table of Contents

What Does the Grade of a Gold Mine Refer To?

By

澳洲幸运5官方开奖结果体彩网:Nick Lioudis

Updated September 21, 2023

Reviewed by

Chip Stapleton

Fact checked by

Ryan Eichler

What Is a Gold Mine Grade?

Gold mines and gold deposits are often categorized by the average proportion of gold contained in the ore at the site. This is also known a🍷s the ore grade. When gold ore has a high gra𝄹de, it has a high density of gold within the ore. Higher ore-grade mines are regarded as higher-quality mines, while lower ore-grade mines are regarded as lower-quality mines.

Mines with lower grade ore due to lower gold density can sti♚ll be profitable if less effort and, therefore, cost is required to extract the gold.

Key Takeaways

All precious metals are graded by the amount of metal within the ore.
A higher grade means that the ore has a higher density of gold.
Gold ore density is measured by grams per tonne or g/t.
Higher-grade mines have densities of 8.0 to 10.0 g/t, while lower-grade mines have densities of 1.0 to 4.0 g/t.
Some of the world's highest-grade mines have been in the U.S., Russia, and Peru.

Understanding Gold Mine Grading

All precious metals are graded by the proportion of metal in the ore. Grams per tonne of milled ore, or g/t, is the most common metric used to repre🍸sent th𝓡e ore grade.

Precious metals are found in a wide range of geological sites. They appear in open pits, underground, under bodies oꦺf water, and in single nuggets resting on the ground. Grading is usually only applied to open pits and underground deposits.

Fast Fact

Gold 𝐆grade ♚and gold purity are two different things. Grade refers to the quality of the gold ore (high-grade ores have more gold). Purity refers to the amount of gold in finished products.

Gold Ore Density

The term "high-quality" underground mine is generally associated with mines that have a gold ore density of between 8.0 and 10.0 g/t. The term "low-quality" underground mine is associated with mines that have a gold ore density of 1.0 to 4.0 g/t.

Open-pit mines tend to have a lower grade, but they can be considered very valuable because of the lower average operating costs of obtaining the gold. Cost per ounce rather than gold ore grading is a recommen👍ded way to evaluate a gold mine.

Based on the g/t standard, some of the world's high-grade gold mines have been located in the United States, Russia, and Peru. For instance, the Fire Creek mine in Battle Mountain, Nevada, was reported to have one of the highest grades at 44.1 g/t. Others making the list include the Macassa mine in Canada, the Kedrovka mine in Russia, and the Toguraci mine in Indonesia.

How Is Gold Purity Rated in Karats?

The purity of finished gold (e.g., jewelry) is often communicated in karats. One karat represents one-twenty-fourth of an alloy. So, 24-karat gold is the purest (all 24 units of a given amount are composed of gold) and is rated as 99.5% or higher pure gold. On the other hand, 18-karat gold is 75% gold and 25% other alloy metals such as tin or copper.

What Are the Biggest Gold Producing Nations?

Historically, most of mined gold has come from China, Australia, South Africa, and the United States.

How Much Gold Has Ever Been Discovered?

All the gold that has ever been mined, plus proven discovered reserves, amounts to around 244,000 metric tons of the metal. If all of that were melted down and fashioned into a cube, it would measure 28 meters (92 feet) per side, which could fit inside an Olympic-sized swimming pool.

The Bottom Line

The grade of a gold mine is generally the average of the grade of gold contained in the site. Grade is usually measured in grams per tonne, with higher grades signifying higher amounts of gold in the mine💯d ore.

Article Sources

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U.S. Geological Survey. "," Pages 18-19.
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