In addition to any penalties heretofore or hereafter provided by law for any person convicted of an unlawful sale of a controlled substance, there is hereby imposed a penalty of five years incarceration in a state corrections facility with no provision for probation if the situs of such unlawful sale was within a three-mile radius of a public housing project owned by a housing authority.
Ala. Code § 13A-12-270 (1975)