Blasting in mines was extremely dangerous. Shot holes were drilled by hand, a charge of gunpowder inserted, tamped, and a fuse lit to fire the hole. Rudimentary powder-filled reed or goose-quill fuses burned unpredictably. There were countless accidents to miners involving blinding, loss of fingers, mutilation and death. In 1830, William Bickford, a leather merchant from Tuckingmill near Camborne, devised a way of introducing a stream of gunpowder into the core of twisted flax yarns which were afterwards bound with twine and sealed with a waterproof varnish of tar. The fuse burned at a consistent 30 seconds per foot. Bickford obtained his patent in September 1831. The production of the safety fuse in Cornwall increased dramatically as more mines adopted it when blasting underground. The Cornish fuse, made not only by the Bickfords but also by other manufacturers such as Bennetts of Roskear (1870) and Tangye’s in Redruth (1886), was sent to mining fields throughout the world. Bickford’s product predominated however, and they soon set up works in America (1837), Germany (1844) and a subsidiary company in Spain (1860). Production further spread with factories in Austria, Australia and Hungary. A century after its invention, the Company was manufacturing 160,000 kilometres of safety fuse a year.