Someone some time ago remarked that some chemists still insist on telling us how to determine copper by the electrolytic method. The writer must confess that he believes that everything is not known definitely as yet as to how the exact amount of copper is determined in such material as purest commercial electrolytic copper. Some … Read more
Wood burning assay furnaces are made with single and double muffles and are much like the soft coal furnaces except that a larger firebox and grate are used. Wood is usually sawed in 2-foot lengths and with dry wood the muffle may be easily heated sufficiently for assaying. Hard wood is much to be preferred … Read more
The object that the writer has mainly in view in presenting this paper is to draw the attention of those connected with the technical side of the industry to the unsatisfactory and by no means up-to-date methods employed in estimating the tin contents of an ore. At the same time, what is regarded, from the … Read more
Among smelters generally, the prevailing opinion is that in a slag which is either extremely acidic or extremely basic in character there is a greater or less loss in silver values. Some assayers have the same notion. Among them also there is the belief that the use of borax in assaying causes low results for … Read more
For years past I have traveled in quest of promising mining- properties, over almost impassable mountain-trails to remote places in the mining-regions, usually many miles from an assay-office. If, upon examination, the formation and the ore-deposit appeared favorable, a quick determination of the value of my samples was necessary, in order that I might take … Read more
Under the title, Labor-Saving Appliances in the Works-Laboratory, I published a paper in which was described how multi-manipulations in a works-laboratory and in the furnace-room of an assay-laboratory, can be condensed into single manipulations by applying the proper mechanical devices. For example, I now deposit in, or withdraw from, a muffle a set of 48 … Read more
After the completion, of the Hammond Mineral Assay & Testing Laboratory of the Sheffield Scientific School, Yale University, it became necessary to secure and assay a large assortment of ore-samples, and to arrange the results in such a manner as to admit of use with the least amount of work on the part of the … Read more
This paper is intended, in the light of recent investigations, to call attention to some of the essential features of good practice in sampling and mine-valuation. Mine sampling may be divided broadly into two classes: development-sampling and computation of ore-reserves; and, stope-sampling and estimation of stope-values. Development Sampling It is with development-sampling only that this … Read more
The so-called “combination method” is generally used in assaying bar copper for silver. It has been modified from time to time. Briefly outlined as now practiced, it is as follows: One A. T. of the borings is dissolved in dilute nitric acid. When solution is complete the liquid is boiled and then filtered to remove … Read more
The Bureau of the Mint of the United States Treasury maintains offices for the purchase of gold-bullion, and this paper describes an investigation to establish the reasonable differences in the assay-results at the various institutions which may be commercially allowable in the settlements between them. Beginning with the comparative assay of proof-gold at the Philadelphia … Read more