Ore Processing Sites

DGC Arsenic Works

DGC 1920s arsenic flue
Believed to be a 1960s view, this shows the stack for the 1920 DGC arsenic works, erected on the stump of a 19th century stack of unknown function, destroyed in 1903 when the old mine was cleared.

Cheryl Manley with the waterfall chamber, erected as a 'scrubber' on the waste flue from the 1920s arsenic works. This sealed structure was packed with brushwood, through which water was directed. The fumes came in at the bottom right and exited, somewhat cleaner, at the top left. The brushwood would be cleared periodically and burnt in a calciner to retrieve the purifed arsenic particles.

The exit hatch from the waterfall chamber on the 1920s waste flue. The arched flue continued just below surface for a further 200m to the right before rising up a 90ft stack to the atmosphere.

General view of the arsenic grinding mill on the 1920s works, built into a former roller-crusher house of the 1850s-60s. This was driven by a rotative beam engine. MAG volunteer Cheryl Manley is standing on the loadings for the crank axle and flywheel of this, which remain stained with bearing grease. Remains of another roller-crusher house on the other side of the loadings, retain the heavy timber beams on which the rollers were mounted. The presence of arsenic oxide has had a preservative effect on timber at this site.

Detail of the stone floor in the 1920s arsenic grinding mill. Using stones no different from those used to grind corn into flour, the crystalline purified arsenic was ground to a fine flour before being barrelled for export.

The sub-frame supporting the grinding stones may incorporate elements of the earlier roller crusher which was sited here in the 1850s-60s.

Cheryl Manley with the east side of one of the 1920s Brunton Calciners. Though probably one of the most recent Bruntons in Devon, their design is no different to the earliest ones of the 1840s. Much rubble lies in the foreground - working ground level is about 1.5m below Cheryl's feet. The flue on the right is not connected with the calciner, but served a reverberatory furnace further down the slope.

The drive axle for one of the 1920s Bruntons, still in-situ. Why this was left when its gear wheel - which fitted onto the square part of the axle - was taken, is uncertain. The combustion chamber containing the revolving plate is above this vaulted chamber.

Brunton Calciner from above, with Cheryl Manley standing in access door. A narrow gauge railway ran along the back of the calciners, bringing crushed ore for roasting.

John Maley in door of a second calciner, with the untopped flue from the combustion chamber to the labyrinth in the foreground. The vertical iron strengthening struts, formed from recycled rails from the 1858-1903 DGC Railway, are typical of Brunton Calciner buildings, where the constant heating and cooling tended to crack up the masonry.

Flues carrying arsenic in vapour form from the calciners, entering the labryrinth where they would be cooled. The metal struts contained sliding hatches to control the flow of the fumes.

View eastwards along the labyrinth. The fumes travelled in a zig-zag manner, the arsenic soot crystallizing out on the walls.

General view of the 1920s labyrinth. The arched doors enabled suitably muffled men to enter the flues to clean the arsenic soot out of the labyrinth at the completion of each burn.

Detailed view of labyrinth side. This is small in comparison with some plants, which could be twice the size in height and chamber dimensions, such as that at Wheal Friendship, Mary Tavy. The old habit of brick-robbing, a favourite pastime of the cash-strapped inhabitants of this area between the 1930s and 1970s, is responsible for the poor state of the structure.

The 1920s stack at the end of the flue system, built on the stump of an earlier stack of unknown function. The rusty yellow dumps from 19th century ore dressing contained much mundic which was recycled for its arsenic content at various local mines in the early 20th century.

Looking up the partially collapsed final flue to the chimney stack. The waterfall chamber is visible as a ruin in the middle distance.

The southern elevation of the 1920s labyrinth, with bricks supplied by Thomas Westlake and Co., who in addition to operating three Tamar Valley brickworks, also processed arsenic.