Analytical Laboratory Design & Equipment
In designing and equipping an analytical laboratory, two aims must be kept always in mind—First, to promote accuracy, and second, to economize time and labor. Don’t make the mistake of sacrificing the former unnecessarily to the latter, but always save time and labor when possible and to that end arrange your laboratory systematically. Nothing so […]
Telluride Assay Determination
The scorification assay for telluride ores has long been believed, and apparently proved, to give low results by reason of volatilization, and it is now seldom used for ores of that class. The assay by crucible is supposed to be far more reliable, and Furman maintains that it is entirely so when properly carried out. […]
Tellurium Assay Determination
Standard tellurium analytical procedures were modified to obtain the greater sensitivity needed to support a survey of tellurium resources by the Bureau of Mines. Resulting volumetric and spectrophotometric methods for determining tellurium in all types of tellurium-containing materials are described. Sample decomposition and preliminary separations of interfering selenium, gold, and silver are the same in […]
Assay Laboratory Accidents
As the assayer at a mine is often called upon to relieve suffering in an emergency the following hints may prove helpful. Burns.—For dry burns apply freely a saturated solution of bicarbonate of soda, till the pain is allayed. The following may be used and is also applicable to scalds: Apply a mixture of bicarbonate […]
Retorting Amalgam & Melting Bullion
It sometimes falls to the lot of the assayer doing commercial work or working in a mining camp to retort the amalgam taken from the plates of a stamp mill and melt the resultant sponge of gold and silver into a bar, and assay the bar so the value of the product may be known. […]
Distilled Water for Assay Laboratory
Why Distilled Water In all operations in assaying and chemical analysis it is desirable to use distilled water. There are very few places where the assayer cannot procure distilled water. How to Purify Water for Laboratory Purposes without Distilling If it is necessary to use ordinary water, add a few drops of nitrate of silver […]
Volumetric Assay Copper Determination by Solution of Potassium Cyanide
The general method of assaying copper values is by what is termed the “wet” process, that is volumetric determination by titrating with standard solution of potassium cyanide. This method is very accurate when carefully done, but care must be taken to keep the standard solution at a given strength. Preparation of Sample The original sample […]
Gold Purity Testing
Description of Touch Stone and Test Needles The touch or test stone is practically a small black whetstone. Test needles (Fig. 47) are a number of slim pointed brass fingers, one end having gold points of different fineness expressed in karats (the karat is the jeweler’s standard of measure for gold, and 24 karats is […]
Smelting Fluxes
General Flux In a laboratory where much work is done in a day, and the class of ore is uniform, what is called a “general smelting flux” may be made. This flux is adapted to ores that may be classified as average, but is so compounded as to allow the addition of extra litharge and […]
Assay Balance Scale for Weighing Samples
Analytical Balances Buy a good button balance, for should the final weighing of the gold or silver recovered from an assay charge be inaccurate, all the previous work will have been wasted. A good button balance can be purchased for $100.00 (Fig. 42); higher grades that are more sensitive and delicate of construction will cost […]