He started work aged 14 in the railway yard in Leon. In 1917 the Union General de Trabajadores (UGT) called a strike in which Durruti was an active and prominent participant. The Spanish Government brought in the Army, to suppress the strike: they killed 70 people and injured more than 500 workers. 2,000 of the strikers were imprisoned without trial or legal process. The Army had, in the words of one observer, 'saved the nation'. Durruti escaped to France.
During his exile until 1920, Durruti worked in Paris as a mechanic. He was persuaded to go to Barcelona to organise the workers there.
In Barcelona, with García Oliver and a number of other anarchists, he founded "Los Solidarios" (Solidarity). Members of this group attempted unsuccessfully to blow up Alfonso XIII the Spanish king. In the wake of this and another botched exploits, Durruti fled to Argentina.
At some point Durruti returned to Spain and Barcelona where he returned to his work of subversion, becoming prominent within the CNT.
On July 24 1936 Durruti led 2000 armed anarchists (later to become known as the Durruti Column) from Barcelona to Zaragoza. After a brief and bloody battle at Caspe, they halted at Pina de Ebro, lacking the weapons for a final assault on Zaragoza.
Durruti eventually managed to obtain weapons from Stalin by sending gold from the national treasury, although these were of poor quality and unreliable.
References:
Emma Goldman's Durruti is Dead, Yet Living (1936)