Gravity Concentration

Free and Hindered Settling

In his paper entitled, Development of Hindered-Settling Apparatus, Dr. Richards has related the history of the development of the hindered-settling classifier and given illustrations of the several types of this apparatus which he has designed. An earlier paper, Close Sizing Before Jigging, shows the nature of the hindered-settling phenomenon and the results which it produces. … Read more

Round Tables Recovery of Minerals from Fine & Slimes

During the last half century a great amount of ingenuity and energy has been devoted to the invention of appliances for the recovery of valuable minerals from very fine sands and slimes. The reason for this is that in almost every dressing plant the greatest losses of values, considered relatively as well as absolutely, occur … Read more

California Gold Dredging

Gold dredging has won an important place in the industry of mining, and it has done so by right of hard-earned merit. Probably no branch of mining has come so prominently to the front in so short a time; by proving its commercial value it has opened to the financier an opportunity for safe and … Read more

Sorting Classifiers

The purpose of this paper is to present a brief sketch of the development of this hindered-settling “sorting” classifier, but primarily to show the actual results obtained in practice with the classifier working on the Butte copper ores at the Boston & Montana Concentrator at Great Falls and the Washoe Concentrator at Anaconda. The writer … Read more

Placer Gold Mining in Colombia

In giving my opinion of the importance of Colombia as a field for investment for those interested in mining for the precious metals, I must begin by quoting Sir Clement Markham, who, in one of his presidential addresses to the Royal Geographical Society of Great Britain, called the attention of its members to the fact … Read more

Tin Mining and Recovery by Sluicing

In this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but … Read more

Vanning Shovel & Frue Vanner

Some time ago, we had to decide the question whether it would pay to re-treat slime-tailings, and several machines were tested in order to ascertain the type of construction which would give the greatest saving. In previous tests on the ore of this company, several tables proved far inferior to Vanning and for this reason they … Read more

Gold Dredge Components & Parts

The design and specifications submitted in this paper are not offered as satisfying all conditions of gold dredging. Many rich stream-beds would not give “ elbow-room ” for such a dredge: many otherwise favorable gold-bearing areas are too small to warrant the cost of its installation; and, in some localities, as I have already remarked, … Read more

Hydraulic Gold Dredging

Repeated failures in attempts to work gold-bearing gravels by means of suction dredges have created the impression that this method is impracticable. The suction hydraulic gold dredges have failed from three special causes: excessive wear and frequent breakage of pump-shell, runners and liners; inability to dredge compact gravel which would not readily move towards the intake; … Read more

Ruble Hydraulic Elevator Ribble Laddler

In many of the old placer-mining districts are still to be found large tracts of gold-bearing gravel not suitable to be worked with a dredge, because the bed is too shallow or the gulch too narrow. Frequently there is not enough grade to handle the gravel successfully by ground-sluicing or a bed-rock flume, or it … Read more