Abstract: A copper bioleaching process which makes use of a consortium which contains Leptospirillum ferriphilum and a sulphur oxidising microorganism which is halophilic or halotolerant.

Abstract: A method of conducting a bioleaching process including the steps of forming a main heap, culturing at least one microorganism which exhibits bioleaching activity in a predetermined temperature range, monitoring the temperature in the main heap, which is a result, at least, of microbial leaching activity and inoculating the heap with the cultured microorganism at least before the temperature reaches the predetermined range.

Abstract: A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below 600 mV (vs. SHE) to cause dissolution of the copper sulphide.

Abstract: A microbiological heap leaching simulation process wherein material, representative of ore in a heap, is microbiologically leached in a housing and the temperature of the material at a plurality of locations in the housing is monitored and controlled to reduce heat loss from the housing.

Abstract: Small magnetic particles are introduced into a solution which is subjected to a bioleaching process. The particles are coated with a substance which has a selective affinity for, and which interacts with, a metal in the solution. The particles are taken from the solution and the metal is recovered from the particles.

Abstract: A heap bioleaching process wherein carbon, in the form of a carbonate, carbon dioxide or organic carbon, is added to the heap when the temperature in the heap is in the range of 45° C. to 60° C. to increase microbial activity and thereby raise the heap temperature to about 60° C.

Abstract: A method for optimizing a bioleaching process, at least in respect of heat generation and primary copper sulphide leaching, by actively monitoring and controlling inorganic and organic compounds in a raffinate solution, produced in the process, to levels below that which could be inhibitory to microbial activity of bioleaching strains used in the process.

Abstract: A method to dissolve at least one metal from jarosite or other iron hydroxyl sulphate containing-material which includes the steps of subjecting the material to alkaline treatment in a brine solution to facilitate jarosite decomposition, and acidification of the brine slurry to solubilise the liberated metal.

Abstract: A method of recovering base metal from a tailings dump which includes the steps of: aerating a surface layer of the dump; adjusting the pH and the moisture content of the surface layer to provide conditions favourable for bacterial oxidation of sulphide minerals; allowing bacterial oxidation to take place for a controlled period, after the controlled period removing the oxidized surface layer and adding water thereto for form a slurry; separating the slurry into solids and a solution; and recovering base metal from the solution.

Abstract: A method of leaching sulphide mineral concentrates wherein heat generated by bioleaching of sulphide mineral concentrates in at least one reactor is transferred into a heap in which bio-assisted leaching takes place.

Abstract: A method of heap leaching wherein a gaseous suspension which contains a microbial inoculum or nutrients is introduced into the heap.

Abstract: A method of leaching sulphide mineral concentrates wherein heat generated by bioleaching of sulphide mineral concentrates in at least one reactor is transferred into a heap in which bio-assisted leaching takes place.

Abstract: A process for producing titanium slag which is low in radioactivity wherein molten titanium slag, produced by smelting ilmenite in the presence of a reductant in a DC electric arc furnace, is separated from molten iron, boron in an amount which is less than 2.5% equivalent B.sub.2 O.sub.3 of the slag is blended with the molten slag which thereafter is allowed to cool to form a glassy phase which contains the bulk of the radioactive elements of the slag before being crushed to particles below about 1 mm, whereafter the radioactive elements are leached to leave a titanium slag product which is low in radioactivity.

Abstract: A process for treating gold bearing sulphide minerals wherein the minerals are subjected to biological oxidation, the product thereof is separated into light and heavy fractions and gold is recovered from the light fraction using a non-biological process.

Abstract: A process for the recovery of copper from a copper sulphide concentrate in slurry form. The slurry is subjected to a biological oxidation turning the copper sulphide to soluble copper sulphate. The liquid containing the copper sulphate is separated from the slurry and treated with an oxime solvent extraction reagent so that copper ions are exchanged by the reagent for hydrogen ions to produce a raffmate which is high in sulphuric acid and low in copper sulphate. The solvent extraction reagent is then stripped from the raffinate with a sulphuric acid solution. Copper is electrically harvested from the sulphuric acid solution and the copper depleted raffinate can be returned to again form a slurry with additional ore for subsequent biological oxidation. The preferred bacterium is one of Thiobacillus Ferro-oxidans, Thiobacillus Thio-oxidans, Leptospirrilum Ferro-oxidans, Thiobacillum Caldus, and Sulpholobus.