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: Provided is a method for treating refractory gold-bearing ores that have both sulfide material with which the gold is associated and from which the gold is difficult to separate and having organic carbonaceous material having an affinity for at least one of gold and a gold complex. The mineral material is pressure oxidized in the presence of a halogen-containing material in a manner to reduce the susceptibility of the organic carbonaceous material to capture and hold gold during the pressure oxidation. Also provided is a gold-bearing effluent product from the pressure oxidation process. The effluent product comprises gold which can be effectively recovered by carbon-in-leach cyanidation of the effluent product. In many cases, gold recovery according to the present invention is increased substantially over standard pressure oxidation techniques.

Abstract: Provided is a method for processing a gold-bearing sulfide ore which involves maintaining the ore in a substantially oxygen free environment, preferably beginning with comminution of the ore and ending when a desired final concentrate, enriched in sulfide minerals, is obtained by flotation. In one embodiment, nitrogen gas is used to substantially prevent contact between the ore and air during comminution of the ore and during flotation operations. It is believed that oxygen gas present in air detrimentally affects the recovery of sulfide minerals in a flotation concentrate through surface oxidation of sulfide mineral particles. The use of a gas such as nitrogen can significantly reduce the potential for such surface oxidation.

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 gyratory mantle liner assembly for use in a gyratory crushing machine including a mainshaft to which is attached a retaining ring having a lip, a conical-shaped upper liner having a serrated and bevelled lower edge, a plurality of lower liner segments and having an upper bevelled edge arranged around the lower circumference of the mainshaft, and a retaining nut for tightening and applying constant force to the upper and lower liner segments to hold them securely against the mainshaft. The lower liner segments defining the crushing surface are generally made of heat treated alloy material.

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 gyratory mantle liner assembly for use in a gyratory cone crushing machine; each assembly includes a retaining ring formed from high density steel having a conical lip on the edge surface thereof, a conical shape upper liner having arcuate teeth and a bevelled lower-end surface on the arcuate teeth formed from mild steel, a plurality of lower liner segments having an upper arcuate tooth surface with a bevelled edge and a seat, and a retaining nut for tightening and holding in position the upper and lower liner segments. The lower liner segments defining the crushing surface are made from heat treated alloy material and are arranged in a ring fashion on the bell skirt without the need for adhesives.

Abstract: A method for sorbing metal values from a slurry containing the same is disclosed. The slurry is advanced through a plurality of vessels arranged in series while countercurrently directing a sorbent through the vessels. Metal values are sorbed from the slurry in each of the vessels by mixing the pulp to achieve homogeneity with the pulp being maintained at a predetermined level in the vessel. A portion of the homogeneous pulp is directed into an interstage screening system disposed within the vessel and at least partially submerged beneath the predetermined pulp level, whereby the sorbent is separated from the slurry. The separated sorbent is primarily returned to the vessel while a portion of the sorbent is removed from the interstage screening system.

Abstract: A method of treating a gold-bearing ore to render the gold component of the ore more amenable to standard cyanidation treatment in a reduced amount of time is disclosed. An aqueous slurry of the gold-bearing ore is introduced into at least one vessel. An oxidizing agent, such as chlorine gas, an alkali metal hypochlorite and an alkaline earth metal hypochlorite, is rapidly introduced into the vessel so that it intimately contacts the aqueous slurry. While the oxidizing agent is being introduced into the vessel, the slurry is agitated with agitating means including a plurality of impeller blades that provide high shear agitation and a large interfacial surface area between the oxidizing agent and the liquid phase of the slurry to enhance the mass transfer of the oxidizing agent so that it becomes substantially completely adsorbed by the aqueous slurry in about 5 to about 15 minutes.

Abstract: A sorption vessel including a tank for retaining a pulp of an aqueous slurry and a sorbent at a predetermined liquid pulp level therein; and an interstage screening system disposed within the tank and at least partially submerged beneath the predetermined pulp level. The interstage screening system includes a housing for isolating the system from the pulp, thereby providing a hydraulic differential between the predetermined pulp level and the screening system; a conduit for selectively introducing the pulp onto the screen member, the pulp being urged through the conduit by the hydraulic differential; and at least one screen member disposed within the housing for selectively and continuously separating the sorbent from the pulp.

Abstract: A vertical pump for transferring a dispersion of solids in a liquid comprising an upper chamber for receiving the dispersion; an intermediate chamber in fluid communication with the upper chamber and including an outlet nozzle for discharging the dispersion; and a lower chamber in fluid communication with the intermediate chamber and including an impeller for inducing a vortex in the intermediate chamber. The dispersion is discharged from the outlet nozzle without deleteriously affecting the solids of the dispersion thereby transferring the dispersion independently of direct contact with the impeller. Generally, the solids are a friable sorbent, such as active carbon, and this pump can be used in combination with a screening apparatus which separates the solids from another liquid prior to delivering the solids to the upper chamber of the pump for forming the dispersion therein.