Patents Assigned to Santa Fe Pacific Gold Corporation
  • Patent number: 5653945
    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.
    Type: Grant
    Filed: April 18, 1995
    Date of Patent: August 5, 1997
    Assignee: Santa Fe Pacific Gold Corporation
    Inventors: John C. Gathje, Gary L. Simmons
  • Patent number: 5536480
    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.
    Type: Grant
    Filed: November 29, 1994
    Date of Patent: July 16, 1996
    Assignee: Santa Fe Pacific Gold Corporation
    Inventor: Gary L. Simmons
  • Patent number: 5458866
    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.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: October 17, 1995
    Assignee: Santa Fe Pacific Gold Corporation
    Inventor: Gary L. Simmons