The Electrolytic Zinc Works were established by the Electrolytic Zinc Company at Risdon beside the Derwent in 1916, due to a number of circumstances: the First World War disrupted the supply from Germany of zinc, vital for munitions; the electrolytic method had been developed to produce zinc cheaply; and the huge amounts of electricity necessary were available through Tasmania's new hydro-electric scheme. Zinc ore came from Broken Hill and Rosebery. Under Herbert Gepp as manager, production started in 1917. In the 1920s the plant developed, with 1300 employees. Work was often hard due to dust, sulphur fumes, hours of shift work (the plant ran 24 hours a day) and the nature of the work, often manual labour with pick and shovel, but the Company provided amenities such as hot showers and, more importantly, security, a Christmas bonus, a training programme with priority for zincworkers' children, and opportunities for promotion, which mostly came from within. This was appreciated: the Zinc Works brought modest prosperity to many who had never known permanent employment, and they became a loyal workforce. In 1984 North Broken Hill took over the Company and modernised the run-down plant. In 1988 North's mining interests became part of Pasminco, one of the world's largest base metal companies. Since then the plant has seen ups and downs with fluctuating zinc prices and more industrial strife, especially as automation meant even fewer employees, but the situation settled. In 2003 the Zinc Works employed 557 permanent staff. Pasminco appointed administrators in 2001, and in 2004 many of its assets, including the Risdon plant, were taken over by a new firm, Zinifex, the refloated company of the failed zinc miner Pasminco. In December 2006, Zinifex announced it would merge its smelting operations with those of Umicore, with the intent of eventually floating the new company Nyrstar. Nyrstar is an integrated mining and metals business, with market leading positions in zinc and lead, and growing positions in other base and precious metals.