ispersed sulphuric acid over a much wider area, reducing the acidity of local precipitation and enabling the city to begin an environmental recovery program. In the late 1970s, private and public interests combined to establish a "regrinding" effort. Lime was spread over the charred soil by hand and by aircraft. Seeds of wild grasses and other vegetation were also spread. As of 2010, 9.2 million new trees have been planted in the city. Vale has begun to rehabilitate the slag heaps that surrounding their smelter in the Copper Cliff area with the planting of grass and trees.
In 1978, the workers of Sudbury's largest mining corporation, Inco (now Vale), embarked on a strike over production and employment cutbacks. The strike, which lasted for nine months, badly damaged Sudbury's economy and spurred the city government to launch a project to diversify the city's economy. Through an aggressive strategy, the city tried to attract new employers and industries through the 1980s and 1990s.
The city of Sudbury and its suburban communities, which were reorganized into the Regional Municipality of Sudbury in 1973, was subsequently merged in 2001 into the single-tier city of Greater Sudbury. In 2006, both of the city's major mining companies, Canadian-based Inco and Falconbridge, were taken over by new owners: Inco was acquired by the Brazilian company CVRD (now renamed Vale), while Falconbridge was purchased by the Swiss company Xstrata. Xstrata donated the historic Edison Building, the onetime head office of Falconbridge, to the city in 2007 to serve as the new home of the municipal archives. On September 19, 2008, a fire destroyed the historic Sudbury Steelworkers Hall on Frood Road. A strike at Vale's operations, which began on July 13, 2009, and saw a tentative resolution announced on July 5, 2010, lasted longer than the devastating 1978 strike, but had a much more modest effect on the city's economy than the earlier action—the local rate of unemployment
