Filtration of Fines & Slimes

The nature of slimes handled in the treatment of gold- and silver-ores has been discussed in technical literature to a considerable extent. The subject of slime-filtration from the practical worker’s standpoint has also received much comment, and scattered through the literature of the subject are descriptions of many slime-filtration installations. Articles of this nature serve … Read more

Grindability of Various Ores

During the last few years, one of the great problems in the milling of all ores has been that of grinding. This subject involves not merely the cost of the operation, but also the selection of the proper degree and character of grinding to yield the best metallurgical results on the given ore. Considering the … Read more

How to Track & Control Metallurgy using Charts & Graphs

The graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley,. N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of metallurgical charts shown in Fig. … Read more

Fine Gold Recovery & Refining

How to Remove Copper from Fine Gold Prevention of copper entering the final bullion has been the principal objective of all experimental work performed on zinc slimes in the goldroom. Above all other metals encountered during treatment, it is the most difficult to separate from gold and silver. Broadly, two methods are possible for elimination … Read more

Precious Metal Refinery Procedures

Recovery of Metals from Mattes and Slags Long ago, mattes and slags, which were the end products of the matte smelting process described in Part I, were sent to Port Kembla for final recovery of their metal content. Approximately 15 tons of slag and eight tons of matte used to be shipped yearly. Shortage of … Read more

Gold Refinery Procedures

Before processing by the gold refinery, gold can be extracted from ore by the following series of operations: Coarse crushing; Fine grinding; Straking for free gold; Flotation; Concentrate roasting; Straking for free, gold; Cyanidation of concentrates; Precipitation of gold from cyanide solution. The last operation is performed in a Merrill-Crowe radial leaf type precipitator, to … Read more


Assaying for ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold is performed by fire assay. This ancient form of quantitative chemical analysis by which metals are separated and determined in ores and metallurgical products with the aid of heat and dry reagents. At present, this technique is used principally to preconcentrate the noble metals from … Read more

Ball Mill Grinding Theory – Crushing Motion/Action Inside

Testing Plant Equipment: In order to determine, among other things, the operating conditions of the ball-mill when working on this rock, a test mill of about 300 T. daily capacity was erected at Duluth, Minn. The fine-crushing plant contains a Hardinge 8-ft. by 22-in. (2.4-m. by 55.8-cm.) conical mill, a 6- by 27-ft. (1.8 by 8.2-m.) … Read more

SX EW Capital & Operating Cost of Solvent Extraction & Electrowinning

Solution mining followed by solvent extraction-electrowinning (SX-EW) is one possible way to economically extract copper from ore bodies which cannot otherwise be profitably exploited. Published costs for the unit processes of SX and EW are out of date especially in view of the newer reagents now available and the newer circuit configurations. This paper updates … Read more

Iron Ore Beneficiation Process

During the last ten years great strides have been made, on the Mesabi range, in the practice of beneficiating low grade iron ore material. By beneficiation is meant all methods of removing impurities, and raising the iron content to a point where it can be sold in open market, the principal impurities being silica and … Read more