Crude Oil Mines

Bitumen Mines - Tar Mines - Asphalt Mine

The Petroleum Oil Wells at Baku on the Caspian. A Fountain of Petroleum Oil. The Illustrated London News 6th December 1886. Public Domain.

This page has a rather unusual title: Crude Oil Mine. Petroleum (petra oleum or rock oil) is a liquid substance and is therefore not extracted by normal mining. This resource is drilled and then pushes to the surface by itself due to its pressure, at least at first. The uncontrolled release of oil and gas from a well while drilling was known as an oil gusher, gusher, blowout or wild well. Due to their natural gas content, however, these blowouts were extremely explosive and were soon prevented by appropriate pressure valves around the well. After all, the escaping oil was environmental pollution, moreover, it was lost for commercial use, and finally, the pressure could be wonderfully used to extract the oil if it did not escape uncontrollably. Later, such incidents only happened as accidents and often led to a well burning.

When the oil reservoir's own pressure is exhausted, the oil must be pumped to the surface. If that doesn't help any more, water is pressed down to drive out the remaining oil. And for some time now there has been an even more aggressive extraction method, fracking, in which oil is even to be driven out of the rock. Nevertheless, the extraction of mineral resources underground must be called mining. Nevertheless, in this case one rather speaks of oil extraction.

Very often it is naively assumed that the extraction of petroleum must lead to huge underground caverns, after all the oil is pumped out. Of course, this is not quite true, the oil is located in pore space, i.e. in small cavities in the rock. If there is no more oil there, it is replaced by groundwater. In the mining process, the substitute, the water, is even pressed down and then replaces the oil.

In general, however, petroleum is a mixture of various hydrocarbons and can occur in different forms. For example, there is oil shale, an oil-bearing sedimentary rock also known as petroleum source rock. This can be mined and the oil it contains can be expelled by heating. If the oil content is high enough, the oil shale even burns, although not very well, and can be used for heating. This was done during the Third Reich to extract oil for petrol. However, the process is not economical.

Then there is oil sand, which is unconsolidated sand, or a very soft (incompetent) layer of sandstone that has been soaked with petroleum. The advantage with oil sand is that it is very easy to mine. You can simply shovel it. In exceptional cases, this was even done underground, for example in Wietze.

And finally there is the term asphalt, in geosciences this term refers to a dark brown to black, tough or solid mixture without any significant mineral substance, Other names include bitumen, natural asphalt, earth pitch or mountain tar. However, it has little to do with the term asphalt in road construction; asphalt is an artificial mixture of tar and sand, optimised for use as a road surface.

Another important aspect is the mining of petroleum as stone oil for medicinal or cosmetic reasons. It was mainly used externally, but even finds its use in medicines. In larger quantities, oil is toxic and carcinogenic in the long term. However, the irritation caused by the rather unhealthy substance is sometimes an incentive for the body to intensify self-healing. And so stone oil was used for eczema, rashes and dandruff. The quantities required are small and were dissolved from the rock by heat, either by burning wood or the oil shale.