A Brief History…
A manufacturing operation to produce bricks was established at the Darley site in 1893 by a partnership between Mr. Thomas Akers and William Wittick. In 1898 David Mitchell, a builder of note, supplier of building products and father of Dame Nellie Melba, joined the consortium with an input of funds to maintain operations. It was realised that the vast clay deposit was eminently suitable for making high quality firebricks and with a further injection of money for expansion in 1902, the Darley Firebrick Company Pty. Ltd. was formed on the 9th of May, with David Mitchell the majority shareholder.
At this time a downdraught kiln and a 30 meter high chimney were built and a steam engine to drive shafts for a pug mill and grinding equipment was installed. By 1907, 4 kilns had been built and a second square chimney for the steam engine was erected. The third chimney to the north was not built until the mid 1940’s along with two extra kilns. Some literature suggests this was done in 1909 but photographs dated around 1942 do not show these structures. The Darley Firebrick Company Pty Ltd. continued to trade under this name until the 13th of August 1982 when the name was changed to Darley Refractories Pty. Ltd. This was done to reflect the extended range of products supplied after the purchase of the assets of the South Yarra Firebrick Company, leaving Darley to be the only producer of firebricks in Victoria.
From the earliest times the clay used was tunneled from a 3 meter high seam, 200 by 500 meters in area, some 17 meters underground. The clay was blasted with gelignite, broken up with mattocks and loaded by hand into skips to be hauled to the stockpile by winch. In 1965 the clay pit was open cut with the removal of around 60,000 tonnes of overburden to expose the fireclay seam. In 1986 the last 15,000 tonnes of clay were removed to a stockpile and the large quarry hole was consequently filled with refuse by the local Shire.
The general method of making firebricks has altered little over a hundred years although the grinding, extruding and pressing equipment has become much more sophisticated. Clays are still ground and mixed with crushed fired aggregate called grog, to stop excessive shrinkage in the material as it is mixed with water and extruded into a soft lump to be pressed into the desired shape. Right up to the 1960’s, many of the larger and special brick shapes were hand moulded. This involved throwing hand sized soft pieces of clay mixture into wooden moulds which had detachable bottom and side inserts shaped to suit the characteristics of the firebrick. A typical full gasworks setting would contain up to 1500 tonnes of firebricks with over 100 different shapes. Many of these contained tongues and grooves to provide a gas tight seal and were hand moulded, as were large “D” shaped pipe retorts up to 5 meters in length also used in these settings.
After shaping and drying, green bricks are fired in a kiln up to 1350ºC to form a ceramic bond giving them strength and integrity. Coke and black coal were used as a fuel to fire the kilns up to 1965 when they were converted to use heavy fuel oil. Probably the most significant improvement to firing was made in 1974, when the change to natural gas occurred. Quality was improved and rejects reduced with the even control of burning temperatures. After 72 years there was no more landmark black smoke from the chimneys, only the occasional wisp of steam.
The most recent improvement in production was the introduction of a 500 tonne Laeis dry press, giving the ability to make precision shaped high quality bricks.
Product sales up to the 1960’s were mainly to gasworks in Australia and New Zealand, foundries, munitions, fireplaces, steam boilers and locomotives. in recent years supplies are still used for industrial boilers, furnaces, aluminium refining pots, wood heater linings and kiln repairs. Castable high temperature refractory concretes are also manufactured and sold.
Historic article written by: Gus Steegstra (previous General Manager)
to commemerate Darley Refractories’ Centenary in 2002.