Fire Assaying; a Miniature Smelting Process
Fire assaying, in essence, is a miniature or small scale smelting process which recovers and reports the total gold content of the assay sample, including gold combined with other elements or locked in the ore particles. Because of this, a assay may report values that cannot be recovered by placer methods and it cannot be […]
Gold Nugget Effect Definition in Sampling
In typical gold deposit (with gravity gold) the variations are so great and the values are so low, any attempt to divide a sample by taking alternate shovels, mechanical splitting, or by other means will invariably yield erratic results. Rather than set out supporting theory which at best would be academic, two examples are offered to show […]
Marcy Scale
Determine the solid content of a mixture a fix volume of slurry is poured into the sample container, this sample volume is fixed because the container is filled until the slurry is even with or over flows through the opening on its side. The container is then hang on the scale and the weight of […]
Mining Geology Sampling Methods: Channel, Chips, Core
Acquiring a representative gold sample is seldom easy and in almost all cases sample results need a large measure of interpretation. Some of the underlying reasons why mining & geology sampling is difficult are: Large particle sizes to be sampled with. A representative sample should contain all of the constituents of a deposit and in exactly the […]
Methods of Testing Cyanide Solutions
The method given above is difficult to apply when solutions containing soluble cyanides of zinc and other metals require to be titrated. “ A white flocculent precipitate occurs at a certain stage, probably consisting of simple (insoluble) cyanide of zinc, formed by decomposition of the soluble double cyanide: K2ZnCy4 + AgNO3 = KAgCy2 + ZnCy2 […]
Cyanide Solution Strength Test
The strength of the cyanide solutions is tested by silver nitrate, using 10 c.c. of the strong and weak solutions respectively (diluted to about 100 c.c. with water) and taking 100 c.c. of wash-water undiluted. In each case a few drops of a 5 per cent, solution of potassium iodide are added. When the titration […]
DIY Ball Mill Plans – Homemade Rod Mill Drawing
By this drawing, it is suggested that a typical homemade laboratory rod mill or ball mill might be fabricated from 20 cm (8 inches) diameter schedule-40 type 316 stainless steel pipe and would be about 38 cm (15 inches) long. The plans show stainless steel grinding rods for this size of mill may be a […]
Metallurgical Testing Program & Management
Metallurgical testing and corresponding flowsheet development programs involve acquisition of certain basic information, a laboratory testing phase, the preparation of reports and, finally, flowsheet development. Management of the basic information includes information relevant to location, the nature of the ore body, sampling, marketing and specifications, environmental guidelines, and a review of literature and current practice. […]
How to Read a Burette
To help you read a burette, first obtain a 3″x5″ card and with a black felt tip pen make a horizontal mark on your card, one inch thick and practically the length of the card. When the top of the black band is held just below the bottom of the meniscus you will see a reflection of the band in the meniscus against […]
Gold Oxides
Aurous Oxide, Au2O This gold oxide is prepared by decomposing aurous chloride, AuCl, or the corresponding bromide by potash in the cold (Berzelius) when a violet precipitate forms, which is blackish when moist, but greyish when dry. When freshly precipitated it is soluble both in alkalies and in cold water, forming an indigo blue solution, with […]