The Duck Lake mine, 17 kilometres from Kerang in Victoria, lies on the largest gypsum tenement in the State, covering 1000 hectares. Owner Cumco Gypsum has been involved in the mining, delivery and spreading of gypsum since 1980. The company supplies natural gypsum to agricultural markets in Victoria and southern New South Wales. Gypsum is used as a soil conditioner, to break down heavy clay soils, and as a fertiliser especially for canola crops.
Duck Lake has reserves of more than 10 million tonnes of high quality gypsum. Grade-one gypsum consists of at least 80 per cent gypsum. Grade-one gypsum from Duck Lake has consistently tested at between 80 per cent and 85 per cent.
Gypsum is naturally occurring calcium sulphate dihydrate that can occur in a variety of forms including coarse crystals, fine crystals and powder. It can be a range of colors including white, grey, red and gold.