As we traveled northwest from Florissant we came to Redstone Colorado where there were these rows of beehive coke ovens that are just off the road. It consists of the remaining examples of the 200 coke ovens built about 1899 for the production of a byproduct of highly heated coal known as coke.
Here at this site are what remains of at least 250 coking ovens. They were built of fire brick in a beehive shape and slack coal was burned in ovens for 48 hours at about 2400 degrees. This resulted in coke that was practically pure carbon that was used in the manufacture of steel.
When the process was completed the end product was taken out of the side of the oven. The heat was so high it left a glassy deposit on the interior of the ovens.
By 1902 they had produced nearly 6 million tons of coke. By 1910 it was abandoned.
In the 1960s and 1970s hippies used them to make dwellings.
So what has all this to do with cars? Well many racers have looked for better brake rotor that can deal with the heat produced and yet be lighter and smaller. High carbon content rotors do just that. They are more expensive than cast iron rotors but they don’t have the heat capacity and thermal dissipation rate of the high carbon variety.
In the early 20th century automobiles didn’t use disc brakes and the coke was used to meet the needs of the railroads.
You can and should read more about the positives and negatives of the production of coal into coke.