Abstract: A pressure leaching system for use in a leaching operation including: at least one reaction zone for receiving a slurry of material to be leached from a slurry source, the reaction zone being disposed relative to the slurry source such that slurry is resident in the reaction zone under gravity thereby providing at least part of the pressurisation required for the leaching operation.

Abstract: A reactor system comprising two or more subterranean reactors for high pressure treatment of materials. The reactors each comprise an inlet tube, a reaction region and an outlet tube and are deep enough for material in the inlet and outlet tubes to produce significant hydrostatic pressure. The reactors are adapted to exchange heat which may occur through a shared heat transferring wall or a heat exchanger including circulating liquid. The invention also extends to a method of simultaneously running two processes in the reactor system. The preferred processes are hydrothermal dewatering of coal, especially brown coal, and coal liquefaction wherein exothermic heat product of one process contributes to the heating requirements of the other process. The invention also extends to a method of hydrothermal dewatering of coal when conducted in a subterranean reactor in conditions of decreasing pressure.

Abstract: A pressure leaching system for use in a leaching operation including: at least one reaction zone for receiving a slurry of material to be leached from a slurry source, the reaction zone being disposed relative to the slurry source such that slurry is resident in the reaction zone under gravity thereby providing at least part of the pressurisation required for the leaching operation.

Abstract: A reactor system comprising two or more subterranean reactors for high pressure treatment of materials. The reactors each comprise an inlet tube, a reaction region and an out let tube and are deep enough for material in the inlet and outlet tubes to produce signifecant hydrostatic pressure. The reactors are adapted to exchange heat which may occur through a shared heat transferring wall or a heat exchanger including circulating liquid. The invention also extends to a method of simultaneously running two processes in the reactor system. The preferred processes are hydrothermal dewatering of coal, especially brown coal, and coal liquefaction wherein exothermic heat product of one process contributes to the heating requirements of the other process. The invention also extends to a method of hydrothermal dewatering of coal when conducted in a subterranean reactor in conditions of decreasing pressure.