Once ignited, the ore heaps usually burned for two or three months. What was left after this stage was transferred to furnaces for a further reduction in bulk. The system illustrated was used in the Sudbury district from 1888 to the late 1920's and was the principal cause of the devastated appearance of the landscape. The dense, sulphurous fumes rolled along the ground, destroying the vegetation, and erosion completed the damage. Although the prevailing wind drove the fumes directly at the fledgling community of Sudbury, local residents seldom complained, partly because they feared the company's power but also because they believed their community's livelihood depended on the company being allowed to use economical smelting methods.
