Search Documents

By S. G. Malghan, A. L. Mular

Size distribution and surface area measurements play an important role in the characterization of crushed and ground granular materials properties. This paper outlines sampling methods of granular materials followed by a detailed treatment of principles of size and surface area measurements of a wide range of sizes from crushers feed to ball-mill ground sub-micron particles. Currently available equipment for size distribution and surface area analysis is described and critically examined with respect to advantages, range of application and precautions in their use. Equipment for on- stream size analysis is also evaluated. Finally, a list of criteria are given for selection of particles size and surface area measuring devices for a particular application.

Jan 1, 1982

By Jack A. Caldwell

Jan 1, 1985

By Allan Gibb

The ores of copper are usually associated with minerals containing arsenic, antimony and bismuth. Whatever the means adopted for extracting the copper, these metals are usually found, to a greater or less extent, in the product. There is, however, usually some elimination in the various metallurgical operations to which the ores are subjected, and some attempt is made here to determine the degree to which this elimination is effected.

Jan 1, 1903

Jan 1, 1898

By H. Baldauf, H. Schubert

The structure of flotation reagents is important for their adsorption on mineral surfaces and thus for their flotation effectiveness. The influence of the structure of organic depressants on the flotation of fluorite and barite with anionic and cationic collectors was investigated using a modified Hallimond microflotation cell. In addition, adsorption, desorption, and electrokinetic results were employed to further elucidate the role and the correlation of the structural parameters for adsorption and the depressing effect. As hydrophilic reagents, different aliphatic and aromatic compounds capable of forming chelates with alkaline earth materials were used. For the depressing effect, the kind, number, and position of the polar groups in the molecule, as well as the structure of the reagent films play decisive roles.

Jan 1, 1980

Jan 1, 1904

By Eric Hedburg

This paper was originally prepared as a picture of the situation presented by the mining industry referred to at the end of the year 1899; and some of the descriptions and drawings of special mines, etc., may not completely show their condition a year later. The statements made as to the cost of mining and concentration, however, still hold good. As to other general statements made in the paper, it is believed that the following additional facts cover all that is required to complete them for the additional year. The condition of the mining industry in the Joplin district was better at the close of 1900 than at any time during several preceding years. Values seemed to have adjusted themselves, in considerable degree, to the commercial and technical circumstances, the cost of mining-supplies of all kinds had returned to a normal basis, and the product of ore found a ready sale,

Jan 1, 1902

By G. T. Jackson

PROPERTY AND LOCATION THE Alaska Gastineau Mining Co.'s mine is located at Perseverance, about 4 mi. east of Juneau, Alaska. Its property consists of a group of claims, the lode system traversing these claims for a distance of 11,000 ft. (3352 in.). It is shown in Fig. 1. FIG. 1.-ALASKA GASTINEAU MINING CO.'S PROPERTY NEAR JUNEAU. The ore deposits occur in what is known as the Juneau gold belt. This gold belt can be traced for about 50 mi. northwest of Juneau and 40 mi. southeast. It consists of a single band, several hundred feet wide, in which stringers and veins of quartz, carrying gold, occur in a slate formation near its contact with some altered volcanic rock known as greenstone.

Jan 9, 1919

Jan 1, 1928

By A. B. Boghani, R. H. Trent

A computer program has been developed to simulate evacuation of a mine in various configurations. The simulation input variables include characteristics of the mine, expressed in the form of a network of passages, properties of hoists and hoisting strategies, initial miner positions, ventilation and compressed air velocities, stench warning system and self rescuer capabilities. The simulation can be carried out for cases in which there is no fire, i.e., fire drill simulation, or for cases in which there is a fire at any arbitrary location. The fire is assumed to generate gases which impede movement of miners in the gaseous region. However, the thermal effects of the fire are not considered. The simulation output include the evacuation time for each miner, movement of the hoists, propagation of smoke through the mine passages and smoke exposure of the miners. Several illustrative simulations have been carried out to verify validity of the program and to demonstrate its capabilities. The computer program has been able to predict evacuation time, within 5 percent, for an actual fire drill. It is believed that this program can be used to evaluate evacuation performance of a mine, identify problem areas and demonstrate improvements due to the recommended corrective actions.

Jan 1, 1977

By Burdett Loomis

The advantages of gaseous fuel have been too fully set forth during the past few years to need recapitulation. Papers, arguments, and editorials have been issued, in a more or less general way, that would make volumes. Systems have found zealous advocates, and many promises of results that have sounded strangely in the ears of old-fashioned gas-makers, have been born of theory, and have died in the earliest throes of trial; while in some few instances success has demonstrated the value of practical effort. With few exceptions, however, everything attempted or accomplished has tended towards the one end-—the realization of more perfect results than we can

Jan 1, 1891

WHEN Magma Copper Company in 1952 set about finding $100,000,000 to finance the project of developing and equipping the property of its lusty progeny, the San Manuel Copper Corporation, A. J. McNab, president and guiding genius for both companies (and incidentally a mining engineer by profession), determined that he would avoid the mistake frequently made in such circumstances, of underestimating the cost, and thereby running short of funds before the job was completed. The fear that this might happen was one of the reasons why insurance companies, one potent source of "big" money, were reluctant to finance the enterprise. How, they asked themselves, would Magma, a relatively small company, get additional money in such a contingency? Insurance officials' thumbs were turned down. Conditions Imposed by R.F.C. The upshot was the negotiation by Mr. McNab for San Manuel of a contract with the Reconstruction Finance Corporation, dated July 10, 1952, whereby needed monies in amount up to $94,000,000 would be advanced as a loan, bearing 5 per cent interest. Arrangements were made for the separate financing of the new $10,000,000 town, needed for the project, through the Del E. Webb Construction Company of Phoenix, Arizona, and M.O.W. Homes, Incorporated, of Los Angeles. Thus the $94,000,000 drawing account was believed ample to provide for building the railroad, the mine plant, the concentrator, and the smelter, as well as for the underground development of the mine needed to start production. As a matter of fact, only

Jan 1, 1957

Jan 1, 1912

By P. R. Bradley

This paper gives a brief history of the mining and milling operations in the Juneau gold belt, and a general description of the geology of the district, followed by a suggestive discussion of the general problem of sampling gold ores and a detailed description of the mining methods used in the Alaska Juneau mine. The paper indicates that variations in assaying ore similar to that from the gold belt are unavoidable on account of the erratic distribution of the gold. A caving system that accepts dilution was adopted for the Alaska Juneau mine; the ore is sorted and the final mill feed has nearly twice the assay value of the ore trammed. THE property of the Alaska Juneau Gold Mining Co., covering the Juneau gold belt for over a mile in length, consists of 136 claims and 24 mill sites; these are near Juneau, Alaska, in what is known as the Harris mining district.

Jan 3, 1924

By G. M. Ritcey

Purification of solutions can involve various treatment methods. In the normal sequence of metals recovery by hydrometallurgy, the ore is initially prepared for leaching by grinding to the desired optimum mesh size as dictated by the leaching parameters. Following leaching and liquids- solids separation, the resultant solution is ready for purification. The use, or introduction of solvent extraction into a plant, can be either a major or a minor part of the metal recovery process as shown by the following list where solvent extraction is normally considered: a) recovery of a metal by a simple leaching of the broken ore, e.g., copper from dump leaching where there are only the three main steps of leaching, solvent extraction, and electrowinning (1);

Jan 1, 1978

By Colin G. Wilson

This paper considers the heavy liquid laboratory tests used to determine the amenability of a potential ore to the heavy media process. The results of the laboratory testing are correlated to actual plant performance and establish design parameters for the heavy media process. These parameters are used in the development of the metallurgical flow sheet and in the sizing of equipment in the metallurgical plant design.

Jan 1, 1978

By George Kunz

(Butte Meeting, August, 1913.) . THE manifold inconveniences resulting from the absence of a uniform standard of mass for determining the weight of precious stones have long been obvious. This lack has been keenly felt in commercial transactions, and those who have devoted time and research to the study of historic diamonds and precious stones have had frequent occasion to deplore the absence of such a standard in the past. In a paper read in Chicago in 1893, before the International Congress of Weights and Measures, held in connection with the World's Columbian Exposition, the writer suggested dividing the carat into 100 parts, and constituting a standard international carat of 200 mg. ; that is, 5 diamond carats or 20 pearl grains to a French gram, making 5,000 carats or 20,000 pearl grains to a kilogram. He also called attention to the fact. that while this would depreciate the present diamond carat or pearl grain only about 2.5 per cent., it-would abolish the troublesome discrepancies between the various carat-weights now in use, and could be easily explained and understood everywhere.1 The subject of the various diamond carats, their incongruity, and the resulting confusion as to the correct. weights of historic gems when definite records of them are searched for, has been fully treated by me in an extensive study of this subject in The Book of the Pearl.2 To the earnest and unremitting efforts of C. E. Guillaume, Director of the Bureau Internationale des Poids et Mesures at Sèvres, is largely due the eventual success of this eminently desirable reform, which he has constantly urged both by articles on the subject and by addresses delivered in Paris before the International Committee for Weights and Measures.2

Jan 7, 1913

By Eifu Moriyama

In 1953, Akita Plant, having a capacity of 560 tons per month, was built at Akita city by Mitsubishi Metal Mining Co., Ltd. for the purpose of treatment of the Ikuno and Akenobe Mines's zinc concentrates. Akita city, in whose neighborhood the black ore has been discovered, is located about 500 Km north of Tokyo and faced with the Japan Sea. This plant has been continuously expanded to have the capacity of 7,500 tons per month by the end of 1969. Efforts have been made to mechanize installations and to achieve continuous process. One of the characteristics of Akita Plant is the recent establishment of the residue treatment process. Many processes had been investigated, and finally commercial sulphate roasting of the residue has been carried out since 1965. At Akita Plant, special high grade electrolytic zinc, zinc alloy for die-casting (MAK brand), cadmium, cement copper and sulphur dioxide gas are produced. Sulphur dioxide gas is sent to the next door fertilizer plant to make acid. Table 1 shows production and the average assay of the electrolytic zinc and cadmium in 1969. This plant is divided into four main sections, two subsections, and residue treatment sections: Main sections are: (M-1) roasting section, (M-2) leaching and purification section, (M-3) electrolysis section, (M-4) melting and casting section,

Jan 1, 1970

By Marc W. Bodine

Insoluble residues from three sequences of Paleozoic marine evaporates (Retsof salt bed in western New York, Salado Formation in southeastern New Mexico, and Paradox Member of the Hermosa Formation in southeastern Utah) are rich in trioctahedral clays. Chlorite (clinochlore), corrensite (mixed-layer chlorite-trioctahedral smectite), talc, and illite (the only dioctahedral clay) are the dominant clay minerals; serpentine, discrete trioctahedral smectite (saponite), and interstratified talc-trioctahedral smectite are sporadically abundant. These clay-mineral assemblages differ chemically and mineralogically from those observed in most continental and normal marine rocks, which commonly contain kaolinite, dioctahedral smectite (beidellite-montmorillonite), illite, mixed-layer illite-dioctahedral smectite, and, in most cases, no more than minor quantities of trioctahedral clay minerals. The distinctive clay mineralogy in these evaporate sequences suggests a largely authigenic origin. These clay minerals are thought to have formed during deposition and early diagenesis through interaction between argillaceous detritus and Mg-rich marine evaporate brines.

Jan 1, 1985

By C. A. Heiland W. E. Pugh

The principle underlying the majority of magnetic intensity variometers is a comparison of the force to be measured with another force of known magnitude. The known force may be (a) of a magnetic nature, such as magnetic fields produced by magnets or coils, or (b) of a mechanical nature, such as (1) the elastic forces of wires, or (2) the force of gravity, such as employed in bifilar magnetometers and magnetic balances. In instruments of such type, usually a magnetic system is employed, free to move about either a horizontal or vertical axis, on some sort of a suspension. If the earth's magnetic field alone were present, such a system would adjust itself into the direction of the field or that of its components. Owing to the simultaneous action of the comparison force, however, the magnetic needle assumes a position that differs from the direction of the magnetic force; for all such instruments, the angle of deflection is given by tan = FIX, where F is the known and X the unknown earth magnetic force component. In other words, the magnetic system merely serves as an "indicator" for the position of balance of the two forces. Considering the matter from this point of view, it is not immediately obvious why the temperature of such a magnetic system should modify the results. In magnetic instruments, we may distinguish two different effects of temperature: (1) a magnetic effect and (2) a mechanical effect. The first is due to the fact that the magnetic moment of a magnet drops with an increase in temperature. This drop is characterized by the temperature coefficient of the magnetic moment (see equation 1). The second effect is due to the change in the torsion of suspension wires with temperature or to the expansion of lever arms of masses acting on magnetic balances.

Jan 1, 1934