Before being an investment currency, bullion or even a financial asset, gold is first and foremost a precious and above all rare metal, with a very small presence in the earth's crust. Studies tend to show that gold accounts for barely 0.003 ppm (parts per million) of the earth's crust.  

Today, gold represents an industry worth several hundred billion dollars, at the heart of the financial markets, jewellery and currency reserves. This economic challenge is compounded by the growing complexity of gold mining and the associated geopolitical and environmental challenges. 

In the following article, we explore in more detail the different categories of gold deposits, their geographical distribution and their strategic and economic importance. 

SUMMARY OF THE ARTICLE : 

• 1) The origin of gold deposits
• 2) Which countries exploit the most gold deposits?
• 3) The strategic and economic stakes of gold deposits

1) The origin of gold deposits 

Gold deposits can be defined as geological formations where gold is sufficiently concentrated to be extracted profitably. Geologists classify gold deposits into several categories according to their geological origin and the way they are formed. The two main forms are : 

• Primary gold deposits (in hard rock) 
• Secondary or alluvial gold deposits (in sediments).  

      Formation of primary or hydrothermal deposits 

These deposits are found in hard rock, where gold is often associated with sulphide minerals such as pyrite. Extraction requires complex mining techniques, such as drilling and blasting. 

They are fluids rich in dissolved metals that circulate in fractures in the earth's crust under the effect of geothermal heat.  

      The formation of sedimentary and alteration deposits 

Gold, liberated from primary rocks by erosion, is transported by water and deposited in river beds. These deposits have the advantage of being easier to mine, often using artisanal or semi-industrial methods. 

2) Which countries exploit the most gold deposits? 

As far as we know at present, some regions seem to be better endowed with gold than others. This is particularly true of the area known as the greenstone belt. This is a volcanic belt that can extend over tens to thousands of kilometres (Australia, Canada, West Africa), volcanic arcs (Peru, Indonesia, Philippines) or ancient sedimentary basins. 

      The main gold producers: 

Unsurprisingly, these main producers are also among the countries with the largest surface areas in the world. They include : 

- AUSTRALIA is rich in orogenic and alluvial deposits. It is also the country with the largest gold mine reserves in 2024, with a theoretical 12,000 tonnes. 

- RUSSIA, which has large deposits in Eastern Siberia and the Russian Far East. This country holds the second-largest gold reserves in the world. 

- CHINA is the world's leading producer, with a variety of deposits (orogenic, porphyry, epithermal). 

- SOUTH AFRICA, which has long been the world leader with the famous Witwatersrand basin. This country has an estimated 5,000 tonnes of gold in its soil. 

- THE UNITED STATES, which has a soil rich in epithermal deposits and the largest gold reserves in the world. 

- CANADA, which mines gold in 10 provinces and territories, but mainly in Ontario and Quebec. 

      Recent gold discoveries in China 

In recent years, China has strengthened its leading role on the world gold market. This has been made possible not only by buying back tonnes of gold, but also by searching for new deposits in its vast territory. There have been two recent discoveries: 

- THE WANGU GISMENT, in Hunan province, in November 2024. The estimated reserves of this deposit are close to 1,000 tonnes of gold, worth around 83 billion dollars.  

This deposit is particularly exceptional in that its gold content is very high, reaching 138 grams per tonne of ore, well above the global industrial average. 

- THE LIANONING DEPOSIT, north-east China, early 2025. This site stretches over 3 kilometres from east to west and 2.5 kilometres from north to south. The latest estimates suggest the presence of around 1,000 tonnes of gold as well. 

3) The strategic and economic challenges of gold deposits 

      Profitability and operating costs 

With the gradual depletion of easily accessible high-grade deposits, the mining industry is now forced to exploit increasingly complex and costly deposits.  

This requires the use of giant quarries and intensive chemical processes, such as cyanidation, which increase costs and environmental risks. 

The profitability of a gold deposit depends on several parameters:  

- The average gold content (expressed in grams per tonne)  

- Site accessibility  

- The extraction methods used  

- The political stability of the host country 

- The host country's regulatory framework 

Future prospects and exploration for new deposits 

Today, the mining industry needs to invest massively in advanced geological exploration. Three major developments are underway: 

- Underwater and extraterrestrial deposits: prospecting projects are targeting the deep ocean. In the more distant future, there are plans to mine asteroids rich in precious metals. 

- Technologies for exploration: 3D geological modelling, artificial intelligence and remote sensing are all revolutionising exploration, optimising costs and increasing success rates. 

- Deep-sea exploration: advances in geophysics and drilling technologies are making it possible to identify previously inaccessible deposits several kilometres below the surface. 

      Geopolitical and environmental issues 

Gold mining has a significant environmental impact: deforestation, soil and water pollution from toxic substances such as mercury and cyanide, not to mention social tensions with local communities.  

Faced with these challenges, a global trend is emerging towards stricter environmental standards (ISO 14001), responsible certification and the development of recycled gold as a sustainable alternative.