Gravity Concentration

Free Milling Gold Laboratory Testing

Friends often ask how accurate the work of our little stamp-mill is, or express the opinion that a little mill cannot do good work. As a reply we would like to place on record the results of a few tests. There are two periods of work in our laboratory; the fall term, when the class … Read more

Silver Lead Ore Processing by Roll Crushing & Jigging

The following brief paper is intended, to apply to the concentration of the silver-lead ores at Broken Hill, New South Wales, generally, but more particularly to the process as applied to the ores in the Block 10 mine. The attached plans are similar in many respects to those prepared recently for the Block 10 Company. … Read more

Centrifugal Elevator: Gold Dredge Tailings Transportation

The centrifugal elevator invented and patented by the writer is designed for the purpose of conveying the tailings of a gold dredge to such a distance that they shall not impede the dredging operations. Formerly this was usually accomplished by means of a belt of buckets travelling round a ladder set at an angle of … Read more

Klein Jig & Classifier

Concentrating-Machinery has been wonderfully improved during the past few years both in technical efficiency and in economy of power; and, in the writer’s opinion, the prosperity which the mining industry has of late enjoyed is due in large part to this improvement. Many properties are yielding handsome profits at the present time which were considered, … Read more

Gold Mercury Amalgamation Methods

I was manager of a mining enterprise where the ores were composed principally of iron pyrites (much decomposed), in a quartz matrix, with native gold in very irregular grains. Some portions, however, carried their metallic value in a matrix of calcite and siderite. The mill in which the ores were treated consisted of two 800-lb. stamps, … Read more

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 … Read more

Plunger Jig & Accelerated Jig

In the discussion of my paper on “ Close Sizing Before Jigging,” Mr. Louis remarks: “ What we really need to know as the basis of any consistent theory (of jigging) is what occurs during each hundredth of a second.” It is clear that for the further study of the laws involved, a jig-tester is … Read more

Working Principles of Jig: Pulsion & Suction

Jig Acceleration Rittinger, having found that jigs save galena of smaller sizes than his formula, worked out in his appendix of the theory of acceleration to account for that fact, showing that a particle of galena which is equal-settling with a particle of quartz reaches its maximum velocity in perhaps one-tenth the time required by … Read more

Pre-Sizing Jig Feed Classification

The extent to which sizing by sieves should be carried, as a preliminary to the separation, by jigging, of minerals of different specific gravities, has been a matter of controversy for many years. The subject has been investigated by several authorities, yet the ground does not seem to have been completely covered, nor are the … 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