Gunnislake's development was primarily due to the dramatic increase in mining and industrial activity in the nineteenth century. Mining provided around 7000 jobs at its peak in 1862. Most mining activity ceased in the late nineteenth century which has bequeathed interest for archaeologists and students of industrial heritage. As well as mining, other industry such as brickworks and quarries were present. Nearby, locations such as Kit Hill, Morwellham Quay, Cotehele and Calstock were mined and quarried and the Tamar was used for transporting the raw material obtained from the works. Arsenic was produced at Greenhill, Gunnislake until at least 1930.