Vibrating Screen

For efficient wet or dry screening—Hi-capacity, 2-bearing design. Flywheel weights counterbalance eccentric shaft giving a “true-circle” motion to screen. Spring suspensions carry the weight. Bearings support only weight of shaft. Screen is free to “float” and follow positive screening motion without power-consuming friction losses. Saves up to 50% HP over 4- bearing types. Sizes 1 x […]

Hardness and Toughness of Rocks

Hardness Toughness Rocks Mineral Composition

The speed of drilling rock has become an important factor in mining operations, while the placement of holes, kind, and quantity of explosive used are equally important. These are a function of the rock hardness and toughness. Both of these factors must be considered in compiling a table that will enable a mine operator or […]

Concasseur

Le concassage constitue la premiere etape de la comminution. Son objectif n’est pas la liberation des mineraux, mais simplement la reduction de dimension afin de faciliter la manipulation ulterieure du minerai. II est normalement fait a sec en deux ou trois etapes. L’alimentation provient de la mine et a une dimension pouvant aller jusqu’a 1.5 […]

Jaw Crusher Working Principle

single toggle jaw crusher

A sectional view of the single-toggle type of jaw crusher is shown below. In one respect, the working principle and application of this machine are similar: the movable jaw has its maximum movement at the top of the crushing chamber, and minimum movement at the discharge point. The motion is, however, a more complex one than the […]

Wilfley Table

wilfley table

The Wilfley table is a truly remarkable gold concentrating table first built on a preliminary scale in May, 1895. The first full-sized table was built by Mr. A. R. Wilfley, and was used in his own mill in Kokomo Colo., in May, 1896. The first table sold for installation was placed in the Puzzle mill, Breckenridge, […]

Ball Mill Grinding

Three “ores” were used in the Ball Mill Grinding experiments. It is doubtful whether material more resistant to grinding can be found among the world’s ores. When flotation was newer and regarded as the panacea in ore treatment, the Tri-State operators were critized for not grinding the entire mill feed to flotation size and thereby […]

How to Remove Quartz & Impurities from Refractory Clays

refractory clays differential thermal curves

Sandy flint and pyritic plastic clays from east-central Missouri can be beneficiated to good firing quality by ore dressing methods. Quartz and pyrite were the chief contaminants removed by the two gravity concentration methods used in the studies. Most iron-oxide minerals in these clays occur as finely-divided, low-gravity, hydrous material, often in the form of […]

Fine Grain Lead Zinc Sulfides Flotation

flotation sketch map of pine creek

This investigation has shown that lead and zinc sulfide minerals, in pulps containing particles all less than 9 microns in size, may be selectively recovered by froth flotation. All but one of the samples yielded lead concentrates-containing at least 57 percent Pb. Selective recovery of lead in the lead concentrate from extremely fine-grained ores was […]

Explosives Explosions and Flames

explosives, explosions, and flames explosibility diagram

This circular summarizes the research and technologic activities and publications of the Federal Bureau of Mines Division of Explosives Technology during fiscal year 1959 (July 1, 1958-June 30, 1959). Part I briefly describes the programs that were active during the report period and presents a summary of some of the information not published elsewhere. In […]

Spectrograph Analysis of Tungsten

tungsten volatilization of germanium

One of the main advantages of this method for estimating impurities in tungsten is that the analysis is performed on the metal. Ideally, samples and standards should be of the same particle size, between 200- and 300-mesh but satisfactory semiquantitative analyses can be made on particles as coarse as 30-mesh. Another advantage is the low […]