The Future of Gold Exploration is Under Cover
Over billions of years, extraordinary amounts of gold and other metals were deposited and spread throughout the Earth’s crust. Humans have been searching for these rich deposits for centuries, and advances in geoscience and technology have helped us become more adept at finding them over time.
However, even with today’s advancements – almost all early-stage prospecting methods are still based on the same key principle: trying to find areas of exposed bedrock, called outcrops, that indicate an orebody is near.
But such outcrops only form in certain circumstances – and what happens when a geological system doesn’t come in contact directly with the surface?
The Problem of Cover
Today’s infographic comes to us from Nevada Exploration, and it identifies the problem behind finding these “hidden” deposits that do not leave a helpful trail of clues on the surface.
Instead of having outcrops where rocks can be readily sampled, these deposits are trapped underneath large amounts of soil and gravel. Geologists call this a covered setting, where they must first find a way to “see through” the cover in order to identify what geological systems really exist below.
Seeing through cover can be expensive and difficult to do, but it also has big potential upside.
There is no reason not to assume as much gold still exists as has been mined in the past, but prospectors, explorationists, and geologists have found the easy gold.
– Dr. Richard Goldfarb, Ph.D., United States Geologic Survey
In fact, many geologists think that the next game-changing gold deposit could be found under cover.
For explorers, it is no secret that the cost per discovery is going up dramatically over time. The reality is that traditional exploration methods are achieving diminishing returns, and as a result companies are settling for lower grade deposits, more complex geological settings, and politically questionable jurisdictions.
Minex Consulting says that between 2007-2016, there has been $65 billion spent globally on gold exploration with only $30 billion worth of discoveries to show for it. Those aren’t exactly inspiring economics for future gold explorers.
But for every industry problem, there is often a precedent to be found elsewhere – and an interesting situation that is analogous was faced by the oil exploration industry years ago. They had reached diminishing returns with shallow water deposits, and developed technology to go deeper. Suddenly, monster deposits were being found again.
Experts involved in mineral exploration see the same thing happening with cover.
With the transition to under cover exploration, the minerals industry is undergoing a transformation much like the petroleum industry transformed to deep sea exploration some decades ago.
– Cam McCuaig, Principal Geoscientist, BHP Billiton
In other words: whoever can figure out how to explore under cover could be reaping big benefits.
In the world’s most prolific gold jurisdictions, there are massive amounts of land that have not yet been explored because of cover. In Canada and in Australia, over 70% of land is covered. In Nevada, which produces the most gold ounces per square kilometer, about 55% of land is covered.
Interestingly, Nevada has produced 225 million oz of gold to date, but the majority of these discoveries have come from outcrop clues on the surface. Imagine what gold could be hidden under soil and gravel within the valleys of the state.
Global data so far suggests that deposits discovered under cover tend to be 2-4x bigger.
Exploring Under Cover
While the idea of unlocking this potential is extremely exciting, it also poses a significant technical challenge.
Conventional tools are poorly suited to covered settings, and existing techniques for systematic exploration don’t work. The end result is high-risk, high-cost exploration.
To successfully explore through cover, companies need:
- New technology to see through cover
- A way to lower the costs of testing targets
- A way to directly test covered bedrock
So far, a few ideas have been pioneered for seeing through cover – and it will be interesting to see what results they bring in.
Biogeochemistry: In Australia, explorers are using biogeochemistry as a hint to see what lays beneath the soil. Plants accumulate pathfinder elements in them, or even tiny amounts of gold, which allows explorers to get a hint at what lies deep below.
Hydrogeochemistry: In a place like Nevada, there are massive valleys in the middle of prolific gold districts that have remained unexplored because they are covered with hundreds of meters of gravel. Testing groundwater might be the key, because groundwater flows by gravity from mountains to deep in the valley centers. On the way, this water interacts with bedrock – and any gold deposits that are hidden beneath the surface.
Explorers are looking at other ideas as well, ranging from regional-scale mapping to adapting other oil and gas industry techniques. If any of them are able to unlock the secret of exploring through cover, it could be the catalyst for industrywide change, as well as the discovery of the monster deposits that will meet our mineral needs of the future.
Gold in Nevada: The Real Golden State
Nevada accounts for 84% of U.S. gold production today. Here’s a look at the state’s rich history, its prolific production, and what the future may hold.
The Real Golden State: Gold Production in Nevada
Thanks to the world famous silver discoveries of the 19th century that unveiled Nevada’s precious metal potential, the state today is known by many as “The Silver State”.
However, it’s possible that nickname may need to be updated. In the last few decades, Nevada has become a prolific gold producer, accounting for 84% of total U.S. gold production each year.
Today’s infographic from Corvus Gold showcases why Nevada may have a better case for deserving California’s nickname of the “Golden State”: we look at the state’s gold production, exploration potential, and even its rich history.
A Defining Era for the American West
The discovery of the Comstock silver lode in 1859 sparked a silver rush of prospectors to Nevada, scrambling to stake their claims. News of the discovery spread quickly throughout the United States, drawing thousands into Nevada for one of the largest rushes since the California Gold Rush in 1849. Mining camps soon thrived and eventually became towns, a catalyst that helped turn the territory into an official state by 1864.
Interestingly, many of the early mines also produced considerable quantities of gold, indicating there was more to the state than just silver.
- The Comstock Lode: 8,600,000 troy ounces (270t) of gold until 1959
- The Eureka district: 1,200,000 troy ounces (37t) of gold
- The Robinson copper mine: 2,700,000 troy ounces (84t) of gold
The Comstock Lode is notable not just for the immense fortunes it generated but also the large role those fortunes had in the growth of Nevada and San Francisco.
In fact, there was so much gold and silver flowing into San Francisco, the U.S. Mint opened a branch in the city to safely store it all. Within the first year of its operation, the San Francisco Mint turned $4 million of gold bullion into coins for circulation.
While California gold rushes became history, Nevada mining was just beginning and would spur the development of modern industry. In 2018, California produced 140,000 troy ounces of gold, just a fraction of the 5.58 million oz coming out of Nevada’s ground.
Nevada Gold Mining Geology: Following the Trends
There are three key geological trends from where the majority of Nevada’s gold comes from.
- Cortez Trend
- Carlin Trend
- Walker Lane Trend
Together these trends contributed nearly 170 million ounces of gold produced in Nevada between 1835 and 2018, making it the United States’ most productive gold jurisdiction, if not the world’s.
The bulk of production comes from the Cortez and Carlin Trends, where mines extract low grade gold from a particular type of mineral deposit, the Carlin Type Gold deposit. It was the discovery and technology used for processing these “invisible” deposits that would turn Nevada into the golden powerhouse of production.
Today, the world’s largest gold mining complex, Nevada Gold Mines, is located on the Carlin Trend. The joint venture between Barrick and Newmont comprises eight mines, along with their infrastructure and processing facilities.
Despite the prolific production of modern mines in the state, more discoveries will be needed to feed this production pipeline—and discoveries are on the decline in Nevada.
Looking to the Future Through the Past: The Walker Lane Trend
The future for gold mining in Nevada may lie in the Walker Lane Trend. This trend is host to some of the most recent gold discoveries, and has attracted the interest of major mining companies looking to conduct exploration, and eventually, production.
Walker Lane stands out with exceptional high-grades, growing reserves, and massive discovery potential. It also played an integral role in the history of the state beginning with the 1859 discovery of the Comstock Lode, and it seems likely to continue doing so in the future.
All the World’s Metals and Minerals in One Visualization
This massive infographic reveals the dramatic scale of 2019 non-fuel mineral global production.
All the World’s Metals and Minerals in One Visualization
We live in a material world, in that we rely on materials to make our lives better. Without even realizing it, humans consume enormous amounts of metals and minerals with every convenient food package, impressive building, and technological innovation.
Every year, the United States Geological Service (USGS) publishes commodity summaries outlining global mining statistics for over 90 individual minerals and materials. Today’s infographic visualizes the data to reveal the dramatic scale of 2019 non-fuel mineral production.
Read all the way to the bottom; the data will surprise you.
Non-Fuel Minerals: USGS Methodology
A wide variety of minerals can be classified as “non-fuel”, including precious metals, base metals, industrial minerals, and materials used for construction.
Non-fuel minerals are those not used for fuel, such as oil, natural gas and coal. Once non-fuel minerals are used up, there is no replacing them. However, many can be recycled continuously.
The USGS tracked both refinery and mine production of these various minerals. This means that some minerals are the essential ingredients for others on the list. For example, iron ore is critical for steel production, and bauxite ore gets refined into aluminum.
Top 10 Minerals and Metals by Production
Sand and gravel are at the top of the list of non-fuel mineral production.
As these materials are the basic components for the manufacturing of concrete, roads, and buildings, it’s not surprising they take the lead.
|Rank||Metal/Mineral||2019 Production (millions of metric tons)|
|#1||Sand and Gravel||50,000|
|#3||Iron and Steel||3,200|
These materials fertilize the food we eat, and they also form the structures we live in and the roads we drive on. They are the bones of the global economy.
Let’s dive into some more specific categories covered on the infographic.
While cement, sand, and gravel may be the bones of global infrastructure, base metals are its lifeblood. Their consumption is an important indicator of the overall health of an economy.
Base metals are non-ferrous, meaning they contain no iron. They are often more abundant in nature and sometimes easier to mine, so their prices are generally lower than precious metals.
|Rank||Base Metal||2019 Production (millions of metric tons)|
Base metals are also the critical materials that will help to deliver a green and renewable future. The electrification of everything will require vast amounts of base metals to make everything from batteries to solar cells work.
Gold and precious metals grab the headlines because of their rarity — and their production shows just how rare they are.
|Rank||Precious Metal||2019 Production (metric tons)|
While metals form the structure and veins of the global economy, ultimately it is humans and animals that make the flesh of the world, driving consumption patterns.
A Material World: A Perspective on Scale
The global economy’s appetite for materials has quadrupled since 1970, faster than the population, which only doubled. On average, each human uses more than 13 metric tons of materials per year.
In 2017, it’s estimated that humans consumed 100.6B metric tons of material in total. Half of the total comprises sand, clay, gravel, and cement used for building, along with the other minerals mined to produce fertilizer. Coal, oil, and gas make up 15% of the total, while metal makes up 10%. The final quarter are plants and trees used for food and fuel.
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