The Sulphide

The Sulphide

Much of northern NSW was underdeveloped when the management of a London-registered company known as the Sulphide Corporation (Ashcroft’s Process) Limited set their sights on establishing an industry in 1895. They were confident they could make a commercial success of the electrolytic zinc process developed by Edgar Ashcroft.

Although the first industrial use of the Cockle Creek site failed after just two years, it left behind two important legacies. First, it advanced the electrolytic process significantly, paving the way for successful electrolytic zinc plants like the EZ Plant in Hobart (now Pasminco Hobart Smelter). Secondly, it began a remarkable period of industrial activity at the Cockle Creek site, which spanned more than a century.

The site has been through enormous change in its 106 year history – World Wars, the Great Depression, population growth, market fluctuations, changes in process, a myriad of different products, and most recently, community and environmental concerns. It grew to be one of the Hunter’s largest employers (at one time employing more than 800 people) and an important economic contributor (in its last year of operation, it contributed more than $80 million to the local economy).


1895 Sulphide Corporation chooses Cockle Creek site for electrolytic zinc plant
March 1897 Plant operations commence
July 1897 Electrolytic process abandoned – decision taken to convert plant to an orthodox lead smelter
1902 First of five zinc distillation plants commissioned
1911 Establishment of Sulphide Employees’ Union
1912 State-of-the-art Dwight and Lloyd sintering machines installed
1913 Sulphuric Acid and Superphosphate Plants commissioned
1917 Full-scale lead refinery constructed and commissioned
1922 Smelting section of the plant closed due to low metal prices
1923 Expansion of acid and fertilizer production
1923 Six Barrier Roasters erected to roast zinc concentrates – gases converted into acid in Chamber units, calcines shipped to EZ in Tasmania
1925 Sulphide Corporation entered its cement production phase
1931 Company directors and salaried staff agree to 20 % wages cut to minimize costs in the wake of the Great Depression
1942 *censored*le Creek works declared a “protected industry” freeing the Corporation from wartime restrictions
1947 Industrial unrest in coalmining, transport and power industries leads Corporation to seek permission to begin coalmining on its own property
Sept 1949 $3 million upgrade announced to double sulphuric acid production and to enable zinc production by the ISF (Imperial Smelting Furnace) process
1950 Sulphide Corporation Limited enters voluntary liquidation, and a new company is formed - Sulphide Corporation Pty Ltd, a wholly owned subsidiary of Consolidated Zinc Corporation Ltd.
1957 Plans announced for an $8 million upgrade to re-establish zinc smelting operations, and expand sulphuric acid and superphosphate plants
Aug 1961 New zinc-lead smelter commissioned at Cokle Creek, ushering in new era of employment, export revenue for both the company and the Port, and 40 % boost in Australia’s zinc-lead smelting capacity
1962 Conzinc Riotinto takes 75% control of Sulphide Corporation
1964 Corporation founds a subsidiary, Greenleaf Fertilisers Ltd, to manage fertilizer production at the plant
1965 Greenleaf begins construction of a $16 million high-analysis fertilizer plant at Kooragang Island ( the first manufacturing plant on Kooragang)
1968 Refinery added to zinc smelter, adding four new products to plant output
1970 Sulphide sells its interest in Greenleaf to Australian Fertilisers Ltd, ending 56 years of involvement in the industry
1972 Employee blood testing implemented
1972 Corporation announces plans for a $3.5 million upgrade of capital plant and $3 million environmental program
1973 Systematic noise reduction program begun, along with regular monitoring of effluents and emissions
1974 Corporation celebrates the production of one million tonnes of zinc and lead – the first ISF in the world to achieve this
1975 Sludge treatment plant commissioned to help remove heavy metals from liquid effluent
1978 $3.25 million investment announced in Lead Dross Leaching Plant – the only one of its type in the world
1980 The Sulphide Corporation Employees’ Union is amalgamated with the Federated Ironworkers Association
1985 Corporation spends $3.1 million on improved technology to increase blast furnace zinc output and place a continuous tapper on the furnace
1988 Pasminco formed with merger of lead and zinc assets of North Broken Hill Holdings Lt and CRA Ltd. $50 capital investment program announced for the *censored*le Creek site including $12 million of new environmental measures
1991 Community health survey reveals widespread soil and dust contamination and elevated blood lead levels
1992 Company announces plans to develop a buffer zone around the plant to ensure the site could meet current and future lead-in-air goals
1993 NSW Government grants development consent for the company’s expansion and improvement program but sets operating conditions among the toughest in the world
1993 Capacity of ISF increased to 90,000 tonnes of zinc per year, automatic zinc slab stacking and strapping introduced, along with improved gas cleaning in the acid plant
1997 $8 million Tail Gas Scrubber constructed, significantly reducing sulphur dioxide emissions
2001 Business Improvement process (BOOM) introduced to Pasminco smelting sites as part of a company wide effort to deliver $100 million in cash savings in a 12 month period
2002 Despite significant improvements, Pasminco announces closure of the site between 2006 and 2008 due to long-standing marginal performance
2003 Closure is brought forward to September 2003 because of the negative movement in key external factors since the original announcement

From: ‘One Last Look – Memories of Pasminco Smelter’

Newcastle Industrial Heritage Association