Production of Oil from Oil Shale
The only current production of oil from oil shale in Colorado is at Shell's RDD project in the Piceance Basin. Volumes are unknown.
Oil shale has a long history of production in the world, starting in 1837 in France (Autun mines, which were closed in 1957), Scotland 1850-1963, Australia 1865-1952, 1998-2004, Brazil 1881-1900,1941-1957, 1972-, Estonia 1921-, Sweden 1921-1965, Switzerland 1921-1935, Spain 1922-1966, China 1929-, South Africa 1935-1960.
Historically, most oil shale production used retorts of one type or another. The rock was mined and then roasted in high temperature kilns that converted the kerogen to oil. That process is being attempted in one of the nine RDD leases from the BLM in Colorado. A diagram of their setup is below.
The other RDD leases in Colorado are experimenting with different varities of in-situ processes, i.e. they are putting heat into the ground and converting the kerogen into oil in place. Below is a diagram of Shell's In-Situ Conversion Process wherein they insert electric heaters into the oil shale.