Patent ID: 6866754

Claim:
Electro-chemical barrier-apparatus, for de-oxygenating water infiltrating into a sulphide-mass, in combination with the sulphide-mass, being a mass of material which includes, as a substantial component thereof, an oxygen-sensitive sulphide mineral, wherein: the arrangement of the combination is such that the electro-chemical barrier-apparatus intercepts oxygenated water moving towards the sulphide-mass; the barrier-apparatus includes an electro-chemical cell, comprising an anode, a cathode, and electrolyte; the barrier-apparatus includes an electrical circuit, which is effective to ensure that electrical energy passes between the anode and the cathode; the electrolyte comprises water infiltrating through the cell, and the barrier-apparatus includes a support container, which is so structured and arranged as to contain and support the water as it infiltrates through the cell, in such manner that the infiltrating water lies in electrolytic continuity between the anode and the cathode as it infiltrates through the cell; the support container is of such nature as to be substantially inert with respect to electrolytic reactions taking place in the cell; the combination is so structured and arranged that water infiltrating into the sulphide-mass is water that has first passed through, and emerged from, the cathode; the cathode comprises a matrix of elements; the elements of the cathode are of electrically conductive material; the matrix of elements of the cathode are so arranged as to create passageways, through which water can pass through the cathode; the barrier-apparatus is so structured as to ensure that water, in passing through the cathode, remains in substantial electrolytic contact with the cathode for a substantial residence time; the anode and the cathode are so structured, and are so arranged in the cell, as to lie separated and spaced apart; the combination includes an electrically-conductive cable, which connects the anode and the cathode; the anode and the cathode are so structured, and are so arranged in the cell, as to provide such current distribution between the anode and the cathode as will ensure that the electrolytic contact and the residence time of water passing through the passageways in the cathode are substantial enough that water emerging from the cathode has an Eh-voltage of less than 0.3 volts; the arrangement of the combination is such as to ensure that the Eh-voltage of the water, after the water has passed through, and emerged from, the cathode, and before infiltrating into the sulphide-mass, remains below 0.3 volts.