This was a combined Arsenic, Brick and Chemical Works.
The Greenhill Works was built in 1875 closing very soon after due to financial difficulties. However it was taken over in 1882 by Gunnislake Clitters mine. At the beginning of the 20th Century it was treating ore from several local mines including the Tavistock mines. The date of closure is uncertain but it is believed to be 1823 but other sources say the plant was still at work until the 1930's.
The site remains are quite extensive with some abandoned buildings and blackened burnt tailings between the railway and the Chilsworthy road at North Dimson, Gunnislake (opposite the Clitters Engine Houses). Further along the Chilsworthy road up on the right are some old building in use as industrial premises and most of all the Arsenic stack (flues mostly gone) which stands at just under 200 ft tall, originally this was 212 ft tall but the top 12 feet were blown off by lightening in 1989!
The buildings of the brickworks are complete and can be found at the side of the road to the left.