The Maddingley brown coal mine in Melbourne's western suburb of Bacchus Marsh, consists of a brown coal formation known as leonardite, a soft, waxy, shiny brown coal that is soluble in alkaline solutions. It contains around 90 percent of humic and fulvic acid, a feature that makes it useful as a soil conditioner, a stabiliser in water treatment programs and capable of lowering certain polluted environments. The brown coal deposit at the Maddingley Mine has been estimated to contain 400 million tonnes of leonardite, the largest of only three other like deposits in the world. The other two being in Mexico and Germany.

Brown Coal Mining Began at the Maddingley Mine in the 1940's
The Maddingley deposit of brown coal was first surveyed in the 1930's and mined during the 1940's when it was transported by rail to the Australian Paper Manufacturers siding at Fairfield, another of Melbourne's western suburbs. During this time the Australian Paper Mill used an average of 400 tonnes of Maddingley coal a day, that was delivered by two train loads a week, for firing its boilers. This market ceased in the 1970's when the paper mill converted to natural gas firing. Maddingley Coal was used between the 1970's and 1980's to fuel boilers at the CRA/Visey cardboard manufacturing plant near the Rowsley Railway Station. However, this factory closed its operations in 1990 and the mine was purchased by the Calleja Group for the dumping of green waste. Four years later, in 1994, the Calleja Group, introduced a technology that created a product known as densified coal. A coal that has its moisture removed and made equal to black coal. It also invested in marketing the coal as a soil conditioner and fertiliser that could replace super phosphate. In 1997 the technology used to successfully produce densified coal was officially recognised as the Coldry Process.

Maddingley Coal Drying Plant Established at JBD Industrial Park
The Maddingley coal drying plant has been established on land that formerly housed the CSR hardboard mill. It is known today as the Calleja Group's JBD Industrial Park. Their tenants at the park include a fertiliser and soil manufacturing plant, a sand producer and an oil manufacturer.
The former Maddingley open cut coal mine that once produced coal for the APM factory became used landfill and a storage site for residual waste resulting from paper recycling.

Landfill Created Leachate at the Maddingley Mine has Been Turned Into Clean Treated Water
As all landfill operations create a substance called leachate, a liquid that contains high levels of substances that are considered harmful to the environment, Maddingley Brown Coal Pty Ltd began on a program to find a waste water solution. The company now supplies clean treated water suitable for irrigation.

The Maddingly brown coal mine was originally purchased by the Calleja Group for its 13.5 million cubic metre hole for use as a landfill site. Although this has continued and the hole is now almost full the remaining coal still continues to be used as a densified coal product and a soil conditioner.