Abstract: The present invention provides a durable offset straight line alignment tool which includes a rigid body having graduated guide lines for stringing offset lines at a construction site. The tool may also include a flat base surface and nailing apertures for nailing the tool to an offset mount at the desired anchoring site and a leveraging catch for a leveraging instrument such as a claw of a claw hammer to easily remove the anchored tool from the anchoring site.

Abstract: A method of flotation processing ores and other mineral materials containing soluble nonferrous base metal and sulfide minerals involves dissolving the soluble nonferrous base metal and precipitating the soluble nonferrous base metal in the form of a floatable precipitate that is collected as part of a sulfide concentrate. The use of an oxygen-deficient flotation gas, such as nitrogen gas, promotes the precipitation of the floatable precipitate. A method for removing dissolved nonferrous base metal from solution involves contacting the solution with a particulate containing sulfide minerals under conditions promoting precipitation of the nonferrous base metal onto the sulfide mineral.

Abstract: Provided is a method involving flotation of a feed of platinum group metal ore material to prepare a platinum group metal concentrate during mineral processing operations. Prior to and/or during the flotation, a lead-containing activator reagent and a xanthate collector reagent are added to the slurry and during the flotation, an oxygen-deficient flotation gas, such as nitrogen gas, is used.

Abstract: A method for the treatment of sulfide ores containing silver by pressure oxidation. The method includes the addition of a sulfate-binding material to reduce the formation of jarosite species during pressure oxidation. Silver can then be recovered from the solids portion of the discharge slurry. A jarosite reduction step, such as by a lime boil, that is typically required to recover silver after pressure oxidation can advantageously be eliminated.

Abstract: Provided is a method involving flotation of a feed of platinum group metal ore material to prepare a platinum group metal concentrate during mineral processing operations. Prior to and/or during the flotation, a lead-containing activator reagent and a xanthate collector reagent are added to the slurry and during the flotation, an oxygen-deficient flotation gas, such as nitrogen gas, is used.

Abstract: A method for the treatment of sulfide ores containing silver by pressure oxidation. The method includes the addition of a sulfate-binding material to reduce the formation of jarosite species during pressure oxidation. Silver can then be recovered from the solids portion of the discharge slurry. A jarosite reduction step, such as by a lime boil, that is typically required to recover silver after pressure oxidation can advantageously be eliminated.

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: 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: 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: Provided is a process for treating refractory precious metal-containing ores, particularly gold-bearing ores, which are refractory due to the presence of organic carbon, to reduce the ability of organic carbon to interfere with recovery of the precious metal. The ore may also contain sulfide materials with which the gold is associated and from which the gold is difficult to separate. The ore is comminuted to a size at which at least about 80 weight percent of the ore is smaller than about 40 microns in size. The comminuted ore is then slurried and subjected to pressure oxidation at severe operating conditions. The treating temperature is greater than about 190.degree. C. When sulfide minerals are present, substantially all of the sulfide sulfur must first be oxidized prior to obtaining significant benefit from the treatment of the organic carbon. Greater than about 96% of the sulfide sulfur must be oxidized.

Abstract: A process is provided for recovering gold from refractory sulfide ores. Preferred feed materials have multiple different sulfide mineralogies, with gold being primarily contained within one or more, but not all, of the sulfide mineralogies. Sulfide mineralogies with the highest gold values are preferentially oxidized, while those sulfide mineralogies with relatively little gold remain largely unoxidized. In one embodiment, dissolved arsenic following pressure oxidation is precipitated as ferric arsenate through the control of pH during neutralization. In another embodiment, the oxidized slurry following pressure oxidation is contacted with an oxidizing agent to convert at least a portion of ferrous iron to ferric iron. Following, pressure oxidation, the slurry can be subjected to cyanidation recovery of gold, and liquid from the tailings stream can be recycled upstream of the pressure oxidation step in a substantially untreated form.