Following the Project Gasbuggy test , two subsequent nuclear explosion fracturing experiments were conducted in western Colorado in an effort to refine the technique . They were Project Rulison in 1969 and Project Rio Blanco in 1973 . In both cases the gas radioactivity was still seen as too high and in the last case the triple-blast rubble chimney structures disappointed the design engineers . Soon after that test the ~ 15-year Project Plowshare program funding dried up . These early fracturing tests were later superseded by hydraulic fracturing technologies
Project Rulison
Project Rulison
Project Gasbuggy