Mineral Reserves

Do you know what the difference is between reserve and resource? If not, let's put it into context. Have you ever played a school sports match? School teams sometimes bring along a reserve player. This player is there to act as a backup during the match, in case any other players become injured. The resource would be the pool of potential team members. Everybody in the class might be able to play the sport. But only the best players would be selected for the team.

In this article, we're going to explore mineral reserves and resources. No need to mine through useless information – everything you need to know is here!

Mineral Reserve: Definition

Let's begin by recapping minerals.

To be classified as a mineral, a compound must have an ordered internal structure. Its atoms are positioned in geometric patterns, often forming crystals.

Figure 1: Amethyst is a popular quartz crystal, made of silicon dioxide (SiO₂). Source: unsplash.com

So, what's a mineral resource?

Not all mineral resources are economically viable. Sometimes, mining the resource would cost more money than you'd make from selling the resource. But the parts of the resource that are economically mineable are referred to as mineral reserves.

As we use up a mineral resource, the cost and effort it takes to extract increases meaning we have to look for new minerals. However, these will inevitably also run out, so we need to get better at conserving resources.

Mineral Reserve: Examples

There are three main classifications of mineral: fuel, metallic, and non-metallic.

• Fuel minerals: used to produce energy

• Metallic minerals: contain one or more metallic elements

• Non-metallic minerals: do not contain any metallic elements

Now, we're going to look at a table detailing some common mineral resources.

Our mineral reserves are directly linked to the economy – and our everyday lives. Minerals are everywhere in our lives: buildings, cars, watches, computers, and phones.

Minerals also indirectly provide electricity. They enable us to switch the lights on and boil the kettle.

Without minerals, our everyday lives would be drastically different. Thus, it's important to conserve mineral reserves to prevent depletion – a.k.a. running out.

Mineral Reserves vs Mineral Resources

Earlier, we learned that mineral reserves are the economically mineable parts of mineral resources.

Mineral reserves refer to the amount of material that can be exploited using existing technology under current economic conditions.

Mineral resources include all the material that can be exploited now or in the future. As technology improves and becomes more affordable, the proportion of mineral reserves will increase.

Future Mineral Extraction

What technologies will increase the size of mineral reserves?

• Improvements in exploratory techniques, including:

  • Remote sensing

  • Gravimetry

  • Magnetometry

  • Seismic surveys

  • Resistivity modelling

• Phytomining: growing plants in soil containing low-grade deposits, then burning the plants and extracting the metal resource from the ashes

• Bioleaching: using acidophilic bacteria to break down low-grade ores, then extracting the metal ions from the acidic leachate

Global Mineral Reserves

Mineral reserves are found across the globe. Some are abundant worldwide, but others are rare, and only found in a few locations.

Lasky's Principle

In simple terms, there is an inverse logarithmic relationship between ore grade and deposit size.

As we develop the technology to extract minerals from low-grade ores, Lasky's principle predicts that we will have access to many more mineral deposits.

List of Countries by Mineral Reserves

There are so many minerals reserves in the world that it's impossible to make one overall list. So, we're going to focus on the top five most commonly mined minerals, and the five nations with the largest reserves of each.

The Most Commonly Mined Minerals

Coal is a carbon-based, sedimentary rock burned as fuel. Coal provides over a quarter of the world's energy. There are four types of coal (classified according to the ratio of carbon and water). From highest to lowest carbon content, they are:

• Anthracite
• Bituminous
• Sub-bituminous
• Lignite

Iron is the primary component of steel; a strong alloy used in engineering and construction. It's found in four different ores:

• Magnetite – 72.4% iron
• Haematite – 69.9% iron
• Limonite – 59.8%
• Siderite – 48.2%

Bauxite (Al₂H₂O₄) is the world's main source of aluminium. This critical metal is used in construction, power lines, electronics, and household appliances.

Figure 2: A bauxite quarry in Italy. The rock is a reddish colour due to the iron compounds found in bauxite ores. Source: unsplash.com Figure 2: A bauxite quarry in Italy. The rock is a reddish colour due to the iron compounds found in bauxite ores. Source: unsplash.com

Phosphate rock contains phosphate ions (PO₄³⁻). The primary use for phosphate is fertiliser production, but other uses include food, medicine, and detergents.

Gypsum (CaSO₄.2H₂O) plays important roles in the agricultural, construction, and textile industries.

Reserve Locations and Sizes

You may have noticed the same few countries cropping up often: India, China, Brazil, Australia, and Russia have a large amount of mineral reserves. They're also some of the world's largest countries by area, suggesting a link between country size and mineral reserves.

Figure 3: An iron quarry in the Karnataka region of India. Source: pixabay.com

I hope that this article has clarified mineral reserves and resources for you. To summarise, a mineral resource is a concentration of inorganic solid material that has a practical use. Mineral reserves refer to the parts of the resource that are economically mineable. Lasky's principle states that there is an inverse logarithmic relationship between ore grade and deposit size.

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