What Is Oil Shale?
This oily type of rock was formed millions of years ago when silt and organic material was deposited on ocean and lake beds.
Over a long period of being under heat and pressure the shale was formed in a similar process to that which results in conventional oil, but to produce conventional oil, the heat and pressure must be greater.
The oil shale normally contains enough petroleum-type oil that it will burn without any processing. This is how it became known as “the rock that burns”Ě.
The term oil shale is generally regarded as applying to any sedimentary rock which contains kerogen (solid, bituminous materials). Kerogens are released as a form of liquid petroleum when the oil shale is crushed and heated in a retort.
How Is Oil Shale Mined?
Oil shale can be mined above and underground, crushed and then transported to a retort where it is heated to a high temperature, and the oil collected in a distiller. This results in an oil similar to that pumped up from conventional underground wells, but the process is more complex and therefore, more expensive at the present time.
Another process, only in the experimental stage at present, is “in situ retorting”Ě which involves heating the oil shale while it is still underground and then pumping the resulting liquid to the surface for further distillation.
Why Is Oil Shale Mining Important?
This extra processing cost and the cheaper availability of alternative fuels, has resulted in the oil shale industry not developing as quickly as it might have, and not finding better technologies to reduce costs and environmental concerns.
With crude oil prices rising recently, the oil shale industry looks likely to kick-on again, with governments and industry pursuing new technologies and development to realise an alternative to conventional oil.
The U.S. and China have large reserves of oil shale. In one area of America alone, there is enough oil to meet a quarter of that countries` present oil demand for the next 400 years!
In Australia, exploration is continuing, and at present Queensland has 90% of the nation`s oil shale reserves. The Queensland Government has just removed the moratorium on oil shale mining, opening the way for more development and improved technology which will result in many jobs in the future.
What Is Oil Shale Mining?