Microfine Gold

Environmental protection measures and hazard costs have negated cyanides effectiveness as a gold lixiviant.
Ammonium thiosulfate has been extensively tested as the best alternative to replace cyanide in gold leaching.
It is available as a cheap fertilizer for economy. Recovery using strong base resins concentrates the gold for
stripping so it can be smelted into dore. Resins are recyclable without regeneration or loss of performance. Gold
selective polymeric resins are being developed to enhance leach stability and further commercialize the process.
Powdered sulfur and caustic is a cheap form of gold lixiviant that when mixed makes a polysulfide/thiosulphate
solution very effective in dissolving gold from its ores. This can easily be converted to thiosullphate leach
using mild aeriation injection. Price $15.00

Most gold production worldwide is from leaching refractory gold deposits. Bulk mineable ores are the number one source followed by sulfide concentration. Knowing how the gold particles occur in the minerals is essential for effective leach extraction. Gold metal is concentrated by first dissolving it from its host mineral then recovering it from solution so it is high enough in grade to be smelted to dore bar. Microfine gold is sometimes difficult to assay due to interference problems caused by adjacent mineral grains. Refractoriness not only involves encapsulation of metal, sealed from leach solution but a co-bonding of metal-mineral at the atomic level on small or thin particle surfaces. Imported ore types are covered including hot spring and sediment-hosted volcanic deposits. (This report replaces Characterization of Microfine Gold in Sediment-Hosted Ores)
Price $15.00

Mineral processing can be a very expensive commercial operation. For any type of ore regardless of the complexity, there are only certain possibilities for economic extraction. Established methods of crushing, grinding, gravity, floatation, leaching, and smelt have to be relied upon for success. Only minor variations will allow one to reach economic end point. The more complex the ore the much greater is the energy cost to break it down, releasing the precious metal. Gravity concentration is an environmentally sound way to concentrate the metals and the minerals that host the metals. Grinding the heavies can separate more metal and minerals for subsequent gravity, floatation, or leach treatment. Automated systems are available but batch and semi-batch methods may be more appropriate, even on a large scale. Leaching is fundamental for separation of gange minerals from iron complexes hosting values. Smelting formulas are critical for converting concentrates to dore metal finish. Price $15.00

A new method of gold ore assay using wet chemical extraction to leach gold from the sample. Chloride chemistry at mild pH is used to selectively leach gold from the crushed rock. This dilute solution chemistry is a better way to evaluate ores since it simulates the media that may be used in a commercial leaching operation. One method is a true quantitative assay measured with colorimetry. Comparing color intensity to standards matches the correct assay value and has been shown to be as accurate as standard analytical techniques. The second method is semi-quantitative using the same non-toxic chemicals. It can be done at the sample location in quick 30 minute tests. Speeding up sampling rates dramatically lowers the cost of doing exploration. Price $15.00