In 1990 Maddingley Brown Coal 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.