Abstract: A system and method for recovering gold using pressure oxidation is disclosed. In one embodiment, a feed slurry is introduced into multiple compartments or stages of a multi-stage autoclave. In another embodiment, an agitator pump is disposed in each compartment or stage of an autoclave to draw the feed slurry and oxygen into a pump cavity for intimate mixing. Preferably these embodiments are used in combination, and each is believed to contribute to enhanced utilization of the oxygen within the autoclave.

Abstract: A process for the recovery of one or more metal values from a metal ore material comprising those of one or more values and a matrix material having a sulfur content wherein the sulfur is present in an oxidation-reduction state of zero or less comprising a. forming particulates from particles of said ore and an inoculate comprising bacteria capable of at least partially oxidizing the sulfur content; b. forming a heap of said particulates; c. biooxidizing the sulfur content and d. recovering those one or more metal values.

Abstract: Refractory gold ores are roasted in the presence of added fuels in an oxidizing atmosphere in a fluidized bed at a temperature from 450 to 650° C., which is supplied with oxygen-containing gases; to achieve a low ignition and thus low roasting temperature, sulfur, pyrite or mixtures thereof are used as added fuels.

Abstract: A method is provided for flotation of refractory auriferous sulfide using an oxygen-deficient flotation gas. The method is particularly suited for non-selective flotation of different iron-containing sulfide mineral species. Comminution prior to flotation may be performed in an oxygen-deficient environment.

Abstract: A hydrometallurgical process for the recovery of one or more metal values from a metal ore material in the presence of clays and/or fines material said ore material being comprised of one or more metal values and a matrix material having a sulfur content wherein the sulfur is present in an oxidation-reduction state of zero or less. The process comprises forming particulates from particles of said ore material, particles comprising said clays and/or fines material, an acid-resistant polymeric agglomeration aid and an inoculate comprising bacteria capable of at least partially oxidizing the sulfur content; forming a heap of said particulates; biooxidizing the sulfur content and recovering those one or more metal values.

Abstract: A tube connector utilized in connecting a drip tube to a header pipe in a heap leach mining percolation system which provides for strength at the normally weak connection between the header pipe and the drip tube. The tube connector includes a housing providing a fluid passageway extending therethrough between a header pipe and a drip tube. A nipple section is formed at one end of the housing for accommodating the drip tube therearound which is of a relatively short length, and hence, a relatively short bending movement, to significantly reduce breakage of the connector during transportation.

Abstract: A process for biooxidation of sulfides in a heap of mineral ores by freeing precious metals dispersed or occluded within said ores as pyritic or arsenopyritic sulfides and the like; the process comprises forming particulates from ore particles with an inoculate comprising bacteria capable of attacking, by biooxidation, sulfides and/or elemental sulfur in said ore particles; from these particulates a heap is constructed; and the biooxidation takes place in such heap by adding to or dispersing within the heap a leaching solution, circulating the leaching solution within the heap and recovering the precious metal values from the heap; recovery may be accomplished with a cyanide, thiourea, or a thiosulfate lixiviant.

Abstract: A method is provided for the recovery of precious metal values, such as gold and silver, from refractory carbonaceous, or carbonaceous-sulfidic ore material. The ore material is inoculated using a specific microbial consortium and then incubated to deactivate the carbonaceous component of the material to prevent binding of the precious metal values to the carbonaceous component. The precious metal is then recovered.

Abstract: A method is provided for the recovery of precious metals, such as gold and silver, from refractory carbonaceous sulfidic material. The carbonaceous sulfidic material is ground and placed in heaps or piles or pulped or slurried and bioleached to oxidize the sulfide minerals using bacteria at temperatures from about 15.degree. C. and up to about 40.degree. C. The biooxidized residue is then treated using a specific microbial consortium, or a product of the microbial consortium, at temperature from about 5.degree. C. to 40.degree. C. to deactivate the carbonaceous component of the material to prevent binding of the precious metal to the carbonaceous component. The precious metal liberated in the residue remaining from the biological oxidation of sulfide and deactivation of carbon are recovered by dissolution.

Abstract: Recovery of a precious metal value from refractory carbonaceous and sulfidic ores, concentrates or tailings which also include arsenic-containing components is improved by roasting the ore or ore concentrate in an oxygen-enriched gaseous atmosphere having an initial oxygen content from about 25 percent (by volume) to about 65 percent (by volume) while maintaining a reaction temperature of less than about 600 degrees Celsius during the roasting and while maintaining a minimum amount of iron to react with arsenic and for forming ferricarsenate; thereafter recovering a thus-roasted ore as calcine, whereby the calcine is amenable to recovery of precious metal values in it; gold ores are preferred candidate ores.

Abstract: A process and apparatus for continuous copper smelting, slag conversion, and production of blister copper in the same furnace by enriched oxygen containing gas injection.

Abstract: Apparatus and method for removing coherent noise from an electrical signal, such as powerline noise, and operating in real time. An operational amplifier with digital filter and a low pass filter in the feedback loop, with the digital filter providing a feedback signal corresponding to the coherent noise in the absence of the desired signal. In the preferred embodiment, an integrating type digital filter with digital memory, and alternative embodiments with condenser memory.