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 contains too many boulders to be worked successfully with the ordinary hydraulic pipe or tube elevator.

In southwestern Oregon, two practical placer-miners named Ruble, after working for years trying to make money out of placer-ground containing many large boulders, invented and patented a hydraulic elevator of an entirely new type, and one that has been found to work very successfully in flat ground and in gravel containing many large boulders. It is a very simple contrivance.

A few years ago I acquired the property near Pierce City, Idaho, known as the American placer-mine. Various attempts had been made to work this ground. A bed-rock flume had been installed by one company, an Evans elevator by another, and still other methods were tried on a smaller scale. All were unsuccessful. I installed a Ruble elevator, and it has proved very satisfactory. Working under 100-ft. (pipe) head, the ground

Mineral Assay & Testing Laboratory Services

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 instructor.

At first, pulp-samples, together with their respective assays, were secured from the mines, smelters, and public assayers, but this practice did not prove satisfactory. It was not only difficult to secure a sufficiently large supply of material, but it was also impossible to secure the proper assortment required for instructing students. It involved considerable work for the donors to select the samples and furnish a record of the assays, and also for the instructors to examine each pulp and determine its character. Some of the samples did not contain a sufficient quantity of pulp for the student to check his work in case his first assay did not correspond to the record.

In order to increase the number of samples and to vary the character of the material, pulp-samples were later mixed with barren rock and with sulphides, but this method also was unsatisfactory and has

Amalgamation Pan

The aim of instruction in a metallurgical laboratory is to make real the principles on which metallurgical processes and operations are based, and to foster the spirit of investigation. The materials with which experiments are carried out are ores, metals, and metallic compounds. The method varies with the end sought. A class may work as a whole, each member contributing his share to the solution of a problem, or the students may carry on investigations independently; the former exemplifies class-research; the latter, individual research. It is with a branch of the former, with special reference to ore-treatment, that the present paper deals.

In smelting an ore by a well-established process, the result is shown by analyzing the products to see whether their compositions correspond to those calculated in making up the charge; by taking account of stock to show the distribution of metal in the different products made and the losses from dust and volatilization; by casting a thermal balance to find the distribution and losses of heat; and by making a cost-sheet to ascertain, as far as possible, the necessary outlay of money.

In lixiviation and amalgamation, the mode of operating has to be varied to adapt a

Jigging Minerals: Galena – Sphalerite

Summarizing some of the principal points brought out in this laboratory Jigging of Minerals’ investigation, I believe the following may safely be accepted:

  1. The pulsion-reaction is by far the most important one in the process of jigging. During this period, with sized grains of different specific gravities, with proper pulsion-velocity, the separation between them will be complete. The size-limit is indicated by the hindered-settling ratio. If the minerals are not sized, or above these ratios, the separation cannot be complete, but a definite arrangement will result. The positions of equilibrium will be attained when the above ratios of diameters arc attained, after which further separation by pulsion is impossible.jigging_machine
  2. Suction due to the movement of water-columns supplements gravity. Resisting the sum of these two forces is the resistance of the walls of the tube through which the grain must pass. The reaction, as a whole, must therefore be a resultant. The chief component is the force of the water-columns, which are purely non-selective, but act with equal intensity upon all particles of the same shape and size, regardless of their specific gravity or weight. Any advantage that the small heavy grain would have


The jig, in one form or another, continues to hold a leading place among the machines designed to separate two or more minerals of different specific gravities. It is simple in construction, easily operated, capable of treating large quantities in a short time, and highly efficient under various conditions.

The question, whether the material to be jigged has first been sized, determines the two principal methods of jigging. Jigging preceded by close sizing, generally known as the Continental or German system, involves a more or less elaborate series of screens or trommels, with attendant cost for installation, operation, and repairs. Jigging without sizing, known as the English system, is, according to Munroe, “ a development of the hand-jigging formerly employed in Cornwall and introduced by English miners to this country.” In its simplest form, the method consists in jigging an ore-mixture previously crushed to some maximum size (although, in some cases, even this preliminary is omitted) on a relatively coarse sieve, and then jigging again on a finer sieve, the material passing through the first sieve and bedding. While many modifications have been necessary to adapt it for use in mills of large capacity, where hand-work was necessarily

Hydraulic Jig Concentrator VS Shaking Table

Concentration of grains from 10 to 30 mm. is effected by hydraulic jigs with two compartments, and in the case of the smaller grains down to 2 mm. by jigs with five compartments. The construction of the jigs is the same in both cases. Fig. 3 gives the details of a jig with two compartments; it is formed of three cast-iron plates which support the bearings of the eccentric shaft, joined by a wooden casing or wooden walls so as to form two communicating chambers for pistons and screens. This construction has no special advantage beyond facilitating the transportation and mounting of the jigs. But in some details the Monteponi jig differs greatly from those in general use.

The eccentrics have a variable stroke. A first eccentric fixed to the shaft is surrounded by a moving eccentric; the first has a flange which partly covers the second at the side, and both have holes through which the bolt is passed to hold them together. The holes being at a different distance in the two eccentrics, the combination forms a kind of vernier caliper, which allows variation in the eccentricity.

Eccentrics of three sizes are used: one for strokes up to 20 mm.; a

Difference between Crushing and Grinding

When making comparisons of the efficiencies of different grinding and crushing machines it is desirable to be able to estimate the work actually done in crushing the ore from a given size of feed to a given size of product, the screen analysis of both feed and product being determined. Messrs. Klug and Taylor, in a paper on this subject, published in the monthly journal of the Chamber of Mines, have described a method adopted by them in calculations made in connection with a series of trials of grinding pans. Their method is based upon the assumption that if a quantity Q of material consisting of particles of average diameter x be crushed down until the average diameter of the particles is y then the work done in grinding is proportional to Q x²/y². There is no theoretical basis for this assumption that the writer is aware of, and it does not appear to satisfy the fundamental conditions necessary. If the material be further crushed until the diameter become z, the additional work done is measured by Q y²/z². Now the work done in crushing from diameter x to diameter z in one operation is proportional to Q x²/z²,

Underground Gold Mine Development Sampling & Ore Valuation

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_ore-valuation_of_gold-mines

  1. development-sampling and computation of ore-reserves; and,
  2. stope-sampling and estimation of stope-values.

Development Sampling

It is with development-sampling only that this paper deals—the term development being taken to mean the opening-up of a mine by cross-cuts, drives, connections, etc., preparatory to actual extraction of the ore for milling. In development-sampling the work of the sampler and the consequent estimation of the probable value of the mine or portions of the mine, as the case may be, cannot be verified until a later period, when the ground thus sampled has been exploited; hence, extreme care and accuracy are essential. Moreover, the development-sampler has to foresee and allow for contingencies which may arise when stoping is started. It follows that the sampling, in development-work, demands familiarity with the conditions likely to be encountered later in actual mining. In stopes, on the other hand, sampling is done under actual working-conditions, and the sampler’s valuations are immediately checked by the

Assaying Gold & Silver from Copper Alloys

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 gold. The filtrate is treated with sufficient salt solution to precipitate all the silver, but avoiding any unnecessary excess. The liquid is allowed to stand overnight and next morning the silver chloride is collected on a fresh filter, which, together with the paper containing the gold and insoluble matter, is scorified and cupelled. Formerly many assayers added sulphuric acid to the nitric acid solution of the copper and silver and then acetate of lead, thus producing a heavy precipitate of sulphate of lead which was supposed to entangle the silver chloride and prevent it from passing through the filter. As a matter of fact the use of sulphuric acid and lead salts is entirely unnecessary. Very few assayers now make use of them. If it is not possible to let the silver chloride settle over night, accurate results may be obtained by stirring the liquid vigorously

How to Assay & Evaluate a Gold Bar: Bullion Purity Determination

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 mint and the Utrecht mint, which shows 0.00002 as the closest agreement now possible, nine tables of comparative results, taken from the regular work of the service, are given. These tables begin with very fine gold, produced in an electrolytic refinery, showing close agreement in the assay-results, and follow through decreasing gold fineness and increasing amounts and complexity of base metals to very impure and complex bars produced at cyanide-mills, some of which give widely-varying results. Next is given a series of results on samples, prepared and sent out to various laboratories in the service, to test the influence of different metals and various combinations upon the agreement of the assay-results; 11 samples were sent out and each one was assayed from 44 to 71 times, making a total of 623 assays. To these are added 107 assays of identical samples of coin-gold.

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