Oil mining is a commonly used term, and there is one type of oil deposit that is literally mined: tar sands. In North America the largest such deposits are Canadian tar sands. About 40% of the oil Canada produces comes from tar sands and the industry creates many petroleum jobs.
Alberta Tar Sands
Oil collects in porous locations in the Earth's crust. Sandy deposits are very porous and will hold large amounts of oil. If the sand was located near the surface when the oil collects, tar sands will result. Over time, the lighter, short chain molecules in oil will evaporate first. Examples of light oils include gasoline and diesel.
Longer chains of hydrocarbons are heavier and slower to evaporate. Also, the longer chains are like pieces of string. They are flexible and tend to get tangled up. This tangling prevents evaporation of the heavier chains. It also results in a sticky, thick liquid. The end result of evaporation and tangling is tar.
Many Canadian tar sands are located in convenient places right on the surface. Extracting the tar is literally an oil mining operation. The petroleum jobs include shovel operators, haulers, extraction plant operators, pipeline operators and numerous construction jobs.
In oil mining tar sands, big shovels scoop up the tar sands. The material is heated to melt the tar and the sand is then separated from the oil. The liquified tar can be refined using a technique called catalytic cracking, or cat cracking. This breaks the long chains up into shorter chains which can then be purified in distillation towers.
The oil extraction process is quite energy intensive. That is one of many reasons people oppose the mining of tar sands. In addition, there is enormous environmental damage done, as with any strip mine. There are also issues with transporting the oil to market. The Keystone pipeline from the Canadian tar sands region to the US got caught up in all these problems, and others. As a result, the project has been shelved. Although some potential jobs were lost, the number was actually quite small compared to the number of new oil and gas jobs in the US.
Deposits of tar sands oil have been found in a number of places around the world. Locations include Canada, the US, Venezuela, and the Middle East. At this time, only Canada is actively producing oil from tar sands. That is where the petroleum jobs are located.