Electro Magnetic Separator

The magnetic concentration of iron-ores has been so often and so widely studied and discussed among the members of the Institute that any remarks concerning its general importance, from an economic standpoint, would be superfluous; but it is thought that a description of the Ball and Norton ore-separator, designed for cobbing and separating magnetic iron-ores, … Read more

Tellurides Process Method

The occurrence of the tellurides of gold and silver, even in small quantities, is so rare that their metallurgical treatment has engaged little attention. A residence of several months at one of the few mines in North America the product of which consists entirely of such ore, has led me to arrange a method for … Read more

French Pocket Compass

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any information about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, … Read more

Electrical Accumulators or Storage Batteries

The broad general distinction between primary and secondary batteries lies in the fact that in the former the current is produced by the consumption of one or both of the elements composing the cell, while in the latter the elements retain their form as such, and merely pass from one state of chemical combination to … Read more

Roasting Furnace

Invented and first put into use, a “new and useful improvement in rotary ore roasting furnaces,” which was intended “to increase the capacity, effectiveness and working economies of such furnaces.” The following description and accompanying figures are taken from the patent papers: Fig. 1 is a side elevation of the feed-end of the Howell rotary … Read more

Testing Aluminum & Metal Alloys

Some explanation of methods of testing will be given before presenting the record of a series of physical tests of aluminum, other metals and alloys. The test-bars used, 12 inches long and ½ inch square, are cast in green sand, with chills bedded in such a way that the ends of the bar run against them. … Read more

How to Assay Gold Jewellery Scrap

This standard prescribes the cupellation or fire assay method for assaying of gold in gold bullion, gold alloys, and gold jewellery and artefacts covered in IS 1417 “How to Assay Gold” Procedure. The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition … Read more

Magnetite Processing & Extraction Jig

This Conkling Jig (ore-concentrating machine or jig), as it is called, is not entirely unknown, having been used at several places with more or less success; but as yet, I believe, no drawings of it or records of its work have found a place in print. Although the jig will be found to be merely … Read more

Silver Chlorination Leaching by Trough Method

In tank-lixiviation of silver by chlorination, the extraction of the silver from chloridized ore by solutions of hyposulphite salts is performed by filtration. The ore-particles are kept stationary, while the solvent moves down through the mass of ore. The quickness of extraction, other conditions alike, is in direct proportion to the rapidity of the movement … Read more

Silver Ingot Melting

The method of making silver ingots in use at this Mint being radically different from that employed at any other Mint of the United States or, so far as known to me, any Mint in the world, there may be some interest in a description of the apparatus used and a brief history of its … Read more