Non Renewable Types of Minerals Are...
Minerals such as oil, coal and gas were formed over millions and millions of years by naturally occurring heat and pressure deep in the earth. These minerals are not spread evenly over the globe but are clustered in areas where the geological processes occurred.
These minerals are used to generate non renewable energy and as time goes on, they will be in short supply. Developing nations use more oil and coal every year as their standard of living improves.
In countries like the U.S., every increasing demands are put on the power grid to provide electricity for everything from lights to small kitchen appliances.
The most commonly known minerals are the fossil fuels we hear about but there are other valuable minerals the earth provides for our use. These are the precious minerals of silver, gold and copper.
There are several natural processes that can result in mineral formation. The first is magnetic concentration. When volcanoes erupt they create molten rock and as that rock cooled millions of years ago it turned into a solid beneath the earth's crust. In some areas that rock cooled in stages and formed separate layers.
The heavier iron (magnesium) settled to the bottom while lighter weight silicate rock formed a top layer. Different mineral elements such as copper were formed by these variations in layer and weight.
Heated groundwater from volcanic eruptions or geothermal fields is a hydrothermal process that formed minerals. As the heated water drained into cracks it dissolved some softer mineral deposits formed by magnetic concentration.
Common elements in the earth caused a chemical reaction and the result was creating of additional metals. This accounts for areas where gold, lead, zinc, silver and copper are mined.
A third process is sedimentation where weathering over time changes the composition of metals previously formed by magnetic or hydrothermal reactions. The sediment minerals are usually found in creek beds, along the banks of rivers, in the delta mud and on the ocean floor.
Locating and Extracting
There's a lot of pure luck involved in locating mineral deposits and new blueprint to follow that is foolproof. Often drilling for one mineral results in an unexpected mineral source.
Geological maps are often used because the topography common to certain mineral deposits is fairly well known. Thus, geologists have a good idea of what to look for when searching for a particular mineral deposit.
In Utah, the Bingham Canyon copper mine is 2.5 miles wide and ½ mile deep. This is an open pit mine that yields 14 million tons of copper each year. It is the highest producing copper mine on the planet.
Subsurface mining involves creating deep vertical shafts into the surface and slopes. This is used for coal mines where the ore is broken out underground and moved to the surface of shaft mines by huge buckets. When the drilling is on a slope rather than straight down, the ore can be moved to the surface in small rail cars.
Strip mining for minerals near the earth's surface involved a huge trench that is dug to extract minerals. The trench removes rock beneath the layer of soil and the rock is broken, picked up and deposited at one end of the trench. When the trench has been mined, another trench is dug next to the first one.
The waste rock from the second trench is used to fill in the first trench. Strip mining is an ugly business that destroys the entire surface of the area where the mining operation is located.
After minerals and ore have been extracted, a smelting process is often used to melt the minerals and remove impurities. Smelting requires a huge furnace where the ore and the coal used as fuel are added to the top of the furnace while hot air is added at the bottom.
For iron ore, the resulting reaction leaves molten iron and cO2. A byproduct is slag and an exhaust on the smelting furnace releases gases emitted during the heating and purifying process.
Effect on the Environment?
At every turn, extracting minerals from the earth has a toll on the environment. Mining damages the land either by scraping away soil and rock and leave huge scars or by drilling tunnels deep within the earth that can eventually collapse.
Strip miners are required to replace the land they've dug up but the most common way to do this (and the only cost effective way) is to create spoil banks by dumping loose filler dirt and crushed rock into the huge trenches gouged in the surface of the land. The result is a bare, loosely packed area prone to runoff and erosion.
Rain on the spoil bank moves chemicals and sulfur to streams and rivers that can kill wildlife and contaminate ground water. It is estimated that almost 7000 streams in the U.S. have been contaminated with acid runoff as a direct result of strip mining.
We know that use of minerals such as fossil fuels carries a high environmental impact when used to produce electrical power.
In truth, from the first shovel of dirt removed in the extraction, the process of using these minerals poses an environmental hazard.