Assaying Silver Bullion
The apparatus which I shall describe in this paper has been in use for some time at the Silver Bullion Assay laboratory of the Pennsylvania Lead Company’s works, and has been found to give good results, and to be simple and convenient. Steam Bath.—This steam bath is shown by Figs. 1, 2, 3, and 4. […]
Cushioned Crushing Roll
Every millman engaged in the operations incident to the handling of crushing-rolls knows that in ordinary practice, when fine product is desired, the ore-materials delivered to the machine, divided into four sizes, may be estimated, approximately, as follows : This estimate refers more particularly to the requirements of medium-sized rolls and fine crushing. But, depending […]
Silver Lead Bullion Sampling
Several interesting experiments were made in the sampling of the silver-lead bullion obtained from the water- jacket smelting-furnace. The smelting-plant is divided into two portions, known locally as the north furnaces and the south furnaces. The former group comprises nine and the latter six 80-ton water-jacket furnaces, besides which the south group has one small furnace used […]
Mercury Assay Determination Method
The dry methods of assaying mercury-ores and other combinations of mercury all rest upon the volatility of this metal as a beginning. After the separation of the mercury in the form of vapor from the matrix upon which the assay is performed, the mercurial vapors are either condensed upon cold surfaces or received upon a […]
How Bismuth Affects Brass Quality
It is a tradition in the brass industry that bismuth is an injurious element in brass, even more deleterious than antimony; but such a belief has lacked verification. The occasional presence of bismuth in commercial copper (although less frequent than was formerly supposed) led the author to investigate this tradition. The following experiments were conducted […]
Shaker Table & Fine Particles Classification
The adaptation of European methods of concentrating ores to suit the conditions of this country has followed the lines that simplify machinery, diminish labor and increase capacity. Noteworthy instances are the substitution of hydraulic classifiers for the last one or two trommels in the series, and the substitution of a distributing-tank for the slimes in […]
Stamp Mill Performance Diagrams
The object of the present paper is to call attention briefly to a novel method of analyzing the action of the ordinary gravity stamp, which has not only thrown much light upon the exact motion of the stamp-head, but promises also to be of value in determining the efficiency of a new mill before setting […]
Volatilization of Silver Ore: Chloridizing Roasting
The latest revised edition of Mr. C. A. Stetefeldt’s book on the Lixiviation of Silver-Ores, which appeared very recently, contains no mention of the volatilization of silver in chloritization-roasting—an omission which is the more remarkable in view of the fact that in former editions of the work this important subject was noticed. Moreover, Mr. Stetefeldt […]
Steam Stamp Milling with Amalgamation
The use of steam-stamps in the crushing of ore for the purpose of amalgamation has been very limited, and little has been written on the subject. As the writer has been operating a mill of this kind during the past year, it is possible that he may be able to present a few points in […]
Silver Assaying & Cupellation
A great deal has been written of late regarding the loss of silver in assaying; very discordant results have been published by different writers, and much uncertainty exists concerning even approximate losses in a careful determination of silver, as represented by a fire-assay. In the present paper it has been the aim of the writer to […]