This is a wall to be seen on King George V Walk. Such blocks are not limited to Hayle and district, but they are more to be seen here than most places.
5th April 2009
Copper Slag and Scoria blocks
This is the realm of The Cornish Copper Company (which began in 1754 as Sandys, Carne and Vivian) from 1758 to 1820.
The process of smelting resulted in a vast waste of copper slag (2 tons plus of slag to one ton of copper).
The area gained the name of Copperhouse, a not incorrect name either, as houses began to be built of these scoria blocks.
Copperhouse Pool was created by the industry for shipping around 1785 to flood at high tide and to seal with tide gates.
Slag was used to reclaim marshy lands and to form road base. It was also formed into these blocks.
This is a fair method of dating as smelting closed in 1820, copper ore then being smelted in Wales.
Slag is primarily silicon oxide and iron oxide totalling c75%.
After 1820 a stock was still available and blocks continued to be used up until after 1900.
Although free to smelting workers, they were sold for 6d for 20.
The blocks have been found in many parts of Penwith.
It was important not to allow the poured material to cool too quickly, it is assumed the casters used wooden moulds with plaster linings.
There are three different casting shapes to be found -
decorative capping, a building block (12 x 10 x 18 inches) and a very heavy block, not so often seen, of 2 feet in length.
Raymond Forward
