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Table of ContentsDescription of ProcessDistillationModern Retorting ApparatusMelting BullionFlux for BullionMuffle and Furnace Maintenance 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

Table of ContentsWhy Distilled WaterHow to Purify Water for Laboratory Purposes without DistillingA Convenient Form of Apparatus for Distilling Water 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

Table of ContentsPreparation of SampleUsual Assay ChargeMethod of TreatmentDetermining the Amount of CopperHow To Make a Standard SolutionCopper Assaying by Modification of Kerl’ SwedishUsual Assay ChargeMethod of TreatmentCopper Assay DeterminationVolumetric Assays 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

Table of ContentsDescription of Touch Stone and Test NeedlesMethod of UsingAccuracy Possible 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

Table of ContentsGeneral FluxSpecific Fluxes or Flux for Specific CasesFluxes Generally Used & FunctionsScorification 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

Table of ContentsAnalytical BalancesWeightsAssay TonWeighing 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

Table of ContentsDrilling Bullion Bar for SamplingGold and Silver FinenessWeighing Sample Drillings and QuartationCupellationRolling Coronets and AnnealingPartingCalculating the Gold Content of BullionDetermine the Silver Fineness or % of Silver in Gold Bullion Drilling Bullion Bar for Sampling Bullion submitted for assay is usually brought in the form of bars, bricks, slugs or buttons, and a sample of bullion in this form

Table of ContentsWhen is Scorification Assay UsedUsual ChargeMeltingPouring Definition of Term Scorification: Scorification may be defined as a reduction and a partial or preliminary cupellation successively performed in the same container without removal of the container from the muffle until volatilization is stopped by the slag entirely covering the charge. When is Scorification Assay Used Scorification is the proper method of

Table of ContentsClassification of OresSulphide OresFluxingMelting FurnacesCupels and CupellationWeighing and QuartationPartingCoarse Gold in Assay Sample Classification of Ores In fluxing ore for gold and silver, first determine the nature of the sample submitted for assay. Three different classifications may be made in the preliminary examination of ores; first, pure quartz (very glassy or vitreous); second, no quartz (plastic and free from