It seems these folks think km = miles. They also seem to think that "porphyritic" and "olivine" are rocks (one is an adjective and the other is a mineral).
From the FAQ: "We currently put out a significant amount of CO2 per year, so we need a volume of 7 km^3 of rock.
The equivalent amount of hydrocarbons acquired each year is currently greater than a volume of 10 km^3."
From the FAQ: "We currently put out a significant amount of CO2 per year, so we need a volume of 7 km^3 of rock.
The equivalent amount of hydrocarbons acquired each year is currently greater than a volume of 10 km^3."