Part of Wheal Anna-Maria, abandoned mine workings on the Devon/Cornwall border near Gunnislake. Part of Devon Great Consols, the mine covered 3.2 hectares and had over 6,850 cubic metres of arsenic flues. Nearby are huge slag heaps, still sterile of vegetation after 110 years, due to the high arsenic content.
Devon Great Consols is a consolidation of five adjacent mines which were worked for copper and arsenic in the nineteenth and early twentieth centuries. At its peak, Devon Great Consols employed around 1,300 people. The mines were named mostly after the shareholders or their wives – Wheal Maria, Wheal Fanny, Wheal Anna-Maria, Wheal Josiah and Wheal Emma.
Devon Great Consols was in operation from 1844 until 1900 and then again from 1915 to 1930. Copper was extracted first and in total over 750,000 tons of copper ore were recovered. In 1850, the site was regarded as the richest copper mine in Europe.
Copper reserves started to run out around 1870. At this time, demand for arsenic increased due to its use in the dyeing, paint and glass industries as well as a pesticide in the cotton fields of the USA. Unlike copper, large amounts of arsenic were refined on site using the ‘calcination’ process and in total yielded 72,000 tons of product. In the 1870s half the world’s As production was estimated to come from half a dozen mines in the Callington and Tavistock area, including Devon Great Consols.