21.3: Ore Deposits

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How would you find ores?

There are many steps to finding an ore deposit. Find a place with likely geology. Test the soil and rock for the ore mineral or others that are often found with the ore mineral. Drill to test deeper rock and soil. Then make a map and do the calculations. If the deposit is found to be profitable, you can begin mining.

Using Minerals

When you use a roll of aluminum foil or some baby powder, you probably don’t think about how the products were made. You may not even know that those products come from minerals! We use minerals in many everyday items. Minerals have to be located, removed from the ground, and refined before they can be made into the products.

Ore Deposits

A rock that contains important minerals is called an ore. The concentration of valuable minerals in an ore may be high or low.

Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. For example, if you want copper, you need to look at regions with a particular geology. Copper is often found where hot fluids came off of a magma intrusion. Aluminum is found in intensely weathered soils in tropical areas. Some of the valuable deposits may be hidden underground. Some may be at the surface.

To find a mineral deposit, geologists study the geology of a lot of places. They then go to a spot where that type of mineral deposit could be found. They test the properties of the soil and rocks. They look at the chemistry and the physical properties. They determine if a mineral deposit is nearby.

After a mineral deposit is found, geologists determine how big it is. They may drill holes. They will test the chemistry of the rock from the holes. Using this information, they will outline the deposit on a map. This will allow them to determine the size and the concentration of ore minerals. The geologists then calculate the total amount of valuable minerals they think are in the deposit. The ore will be mined only if it is profitable. If so, a mineral deposit called an ore deposit.

The bauxite pictured below (Figure below) is a rock that contains minerals that are used to make aluminum.

Aluminum is made from the minerals in rocks known as bauxite

Aluminum is made from the minerals in rocks known as bauxite.

If a mineral deposit is not profitable to mine, it is not considered an ore deposit. If conditions change, a deposit that wasn't profitable before may become profitable. An ore deposit may also become unprofitable to mine. What could occur to make these changes? The price of the ore could rise or fall. The price of extracting the ore could change. For example, if the ore is hard to get at and the price of fuel goes up. This may make the mineral deposit unprofitable to mine.

Summary

An ore is a rock that contains important minerals.
An ore deposit must be profitable to mine. If it is no longer profitable, it is no longer an ore deposit.
Geologists find ore deposits by testing the chemistry of the rock and soil. They can also determine the size of the deposit.

Review

How can an ore deposit become unprofitable to mine?
How do geologists find an ore deposit?
How do geologists determine the size and concentration of ore?