In September 1966, the USSR economy suffered from several gas well blowouts. This resulted into rapid leaking of gas from these wells which then caught fire. The engineers tried all conventional techniques, including hydraulic fracturing, but failed to control the leak and fire. Eventually, they came up with the idea of exploding a nuclear bomb to control the fire. You might be thinking that they could have used normal explosives but the required amount was just too much. Finally, a 30 Kg nuclear bomb was lowered 6 Km below the Earth surface. Upon detonation, it took 23 seconds to seal the leak and put out the fire.