The story starts with a mining boom in north-west Sheffield and the mining and the production of refractory bricks, which began in the late 1800s. Some joked that it resembled the Wild West as people rushed to cash in from the ganister that lay below their land. Ganister clay was a good quality clay used for making the crucibles for smelting steel. Most of Earth's coal originated as trees. Ganister is the fossilised earth that these trees grew in. It’s also known as laminated clay as, unlike normal clay, it is almost resin-like. As hard as rock, it became a very sought-after material in South Yorkshire. With the advent of the iron and steel industry, it was used to make these furnaces so they could withstand the heat. The ganister was pulverised and then moulded into bricks. These “fire bricks” were then used to line the furnaces.
Thus, during the industrial revolution in 1800s, the Loxley Valley became an important producer of refractory bricks for the Sheffield’s steel industry along with fireclay from Stannington’s pot clay mines. Pot clay was an ‘impure’ form of ganister. The ganister and fireclay mines supplied the local firms such as Siddons Brothers, Thomas Wragg and Sons and Thomas Marshall and Co.
In the 1930s there were a total of three firms in the Loxley Valley, the aforementioned Thomas Marshall’s and Thomas Wragg and Sons along with Dysons, producing hollow refractories. Between them, they supplied 95% of all the hollow refractories produced in Great Britain. When war broke out in 1939, the industry became vital to the war effort. If the Germans had bombed the Loxley Valley successfully, many believe that the war would have been over very quickly. As a consequence, there was a gun site on Wood Lane, Stannington, which shot down several Luftwaffe planes during the Sheffield Blitz. Post the war, all three plants closed following a collapse in demand for casting pit refractories, down to the introduction of continuous casting of steel worldwide and the general demise of the British steel industry.
Latterly and most recently Hepworths were the big producers of refractory bricks in the valley. Production ceased here in the 1990s and the ganister and pot clay mines closed.