Search Documents

By Chas. F. Jackson

The mining literature is replete with descriptions of methods and costs of operation at producing mines. To day the mine manager can find published information bearing upon almost any problem with which he may be faced. From this literature he can familiarize himself with methods employed by otter operators for coping with problems similar to his own, under more or less parallel conditions. Transaction of mining societies, publications of the U. S. Bureau of Mines, technical journals, and handbooks all afford valuable information dealing with operating methods and costs, Very little has been published, however, regarding methods and costs of equipping and developing new properties and bringing them to tae productive stage. There may be some question in the minds of many as to the value of papers on this subject, due to the great variety of conditions encountered. No two prospects are alike. Obviously, it is impossible to forecast what expenditure will be required to develop a mine from a raw prospect or even to predict whether the prospect can be developed into a productive mine.

Jan 1, 1933

By Ernest Ph. Hérivel

The mine and treatment plant of the Teziutlan, unit of the Mexican Corporation, S. A., are located at Aire Libre, in the District of Teziutlan, near the northwest edge of the State of Pueblo, Republic of Mexico. The property is leased from the Teziutlan Copper Co. The town of Teziutlan is the terminus of a branch railroad starting from Oriental Junction or the Mexico-Jalapa-Veracruz narrow-gage system of the National Railways of Mexico. A branch line 18 km in length from Teziutlan to Aire Libre belongs to the Teziutlan Copper Co. and is leased and operated in conjunction with the mine.

Jan 1, 1933

By Milton H. Fies

To present some idea as to how the Bureau of Mines may most effectively serve mining, it is necessary that we make some resume of its pact accomplishments in order to determine what, if any, changes will be of greatest service to the industry and to the nation. There are a great many times in life when one begins to wonder whether or not Emerson, in his famous epigram about "mousetraps" and "beaten paths" and "final recognition of intrinsic worth", took into account the item of time. The intrinsic value of any movement, of any work, of any accomplishment will ultimately be recognized, of that there is no doubt, but may a man in history has gone to his end in martyrdom because the world was slow in the acknowledgement of the true excellence of his worth, and this is likewise true of institutions.

Jan 1, 1934

By T. L. Joseph

The Bureau of Mines gas been studying the blast furnace for a number of years and has published detailed reports on various phases of its investigations. Inquiries frequently received for information of a more general character than that given in the detailed reports have promoted the preparation of an information circular to cover in a general way the important features of the Bureau of Mines blast-furnace investigations. SHAPE AND DIMENSIONS OF FURNACE The modern blast furnace approximate a refractory-lined steel cylinder about 90 feet in height and 25 feet in diameter. It actually consists of a number of cylinders and truncated cones superimposed upon each other. The shape and dimensions of a modern furnace are shown in figure 1. The bottom section, commonly referred to as the hearth or crucible, is a cylindrical section about 12 feet high. Liquid metal and slag collect in this part of the furnace and are withdrawn at regular intervals; iron is removed at a level about 2 feet above the bottom of the furnace and slag at a level about 5 feet higher. Depending upon on the size of tie furnace, 40,000 to 75,000 cubic feet of preheated air per minute is introduced through from 10 to 16 tuyeres equally spaced around the periphery of the hearth.

Jan 1, 1934

By T. H. Miller

An attempt has been mace in this publication to present annotated references to all articles pertaining, to ore dressing that were published during 1931 and 1932; in a few instances reference is made to articles published prior to 1931 where the articles have not been included in previous bibliography appended to the annual statistical discussions of ore concentration published by the Bureau of Mines. Articles have been taken from more than 75 periodicals, journals, serials, etc., and 423 articles are abstracted herewith. A number of these abstracts, particularly those appearing in foreign publications, have been taken from Chemical Abstracts (published by the American Chemical Society, Easton, Pa.), the general use of which the authors wish to acknowledge. Other annotations were taken directly from the original publications. The entire field of ore dressing has been included in the bibliography and articles dealing with crushing, grinding classification, concentration, thickening, and filtration have been included, as well as on amalgamation, cyanidation, leaching, magnetic concentration, washing, etc., and on theory and laboratory operation. The articles are arranged in alphabetical order by authors. Lack of printing funds prohibited the inclusion of a subject index.

Jan 1, 1934

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

By J. R. Thoenen

This circular is the third of a series summarizing the technical problems involved in the production and preparation of sand and gravel. The first, Information Circular 6668, published in December 1932, discussed the problems involved in prospecting and exploration. The second, Information Circular 6689 (March 1933), dealt with the development of gravel deposits. This is part I of a paper designed to present a study of problems arising in the excavation of sand and revel and their delivery to the treatment plant. Other circulars are planned which will discuss preparation of the material for market, plant storage, and miscellaneous subject. Definitions For the purpose of this circular, excavation is defined as the recovery of sand and gravel from developed natural deposits and their delivery to a plant for market preparation.

Jan 1, 1934

By Charles Will Wright

This paper will be of interest to those who are actually developing a mineral prospect or planning to do so, as well as to investors who are considering the problem of financing the development of the prospect, so that they may know what the risks are and what capital expenditures are necessary before a prospect may become a mine. The term "prospect" used broadly, as it is in this paper, is defined as any property that has a mineral showing of sufficient interest to warrant development, irrespective of prior work, Such previous exploration, however, may be extensive and consist of several tunnels or adits connected by raises, or of shafts with several levels. There may also be a small mining and milling plant on the prospect which, because of the lack of capital for development or the lack of markets for the products, is now idle. Such prospects may warrant further capital investment for development work or for a mine plant to raise to the stage of profitable production.

Jan 1, 1935

By S. H. Ash

For several years considerable activity has been devoted to economic and social factors affecting California metal-mining operations as they relate to accidents and their cost. The reason for this intense interest is that accidents cost this industry annually over $1100,000 in industrial insurance premiums for mines insured by insurance carriers only; during 1924-32, inclusive, they amounted to $3,616,9115. There are several reasons for this high cost, the most important of w rich are the consistently .high frequency and severity rates of injuries occurring in the industry. Coordination of effort, appreciation of a mutual problem, and widespread education are essential if accidents and their cost are to be reduced.

Jan 1, 1935

By C. W. Owings

A few of the more progressive mining companies have taken precautions to safeguard employees or man-trips. Specially constructed men-cars -have been provided with special devices or mechanisms to stop the cars on slopes, if the hoisting cable should break. Cars have been equipped with safety chains to connect and hold them together if a coupling should break. Steel frames covered with heavy wire netting have been placed over cars to reduce injuries to the riders from roof fails on slopes. A safety cable passing from the front car to a point above the cable socket on the slope hoisting cable is used frequently as a precaution in case the socket loosens o the main cable breaks at the socket. Such devices are commendable, but the percentage of man-cars and man-trips protected is relatively small - entirely too small. Man-trips that travel level haulage roads are rarely protected safety devices, and haulage roads are seldom inspected by mine officials to determine the condition of roof and ribs.

Jan 1, 1935

By Frank E. Cash

The work of the United States Bureau of, Mines is concerned primarily with the prevention of accidents in the mining, petroleum, and allied industries. This report analyzes the fatal accidents in the coal mines of Tennessee and gives the pertinent factors in tabular and descriptive form, with interpretations and suggestions to operators, workers, and the State Division of Mines for the future prevention or reduction of accidents in coal mines. ACKNOWLEDGMENTS This study was made possible through the cooperation of A. W. Evans, chief mine inspector of Tennessee, and his secretary, Miss Hiliary Penny, who made available the department records and assisted in the segregation and assembly of the data.

Jan 1, 1935

By Frank E. Cash

As a part of its safety program the United States Bureau of Mines has fostered the development, use, and improvement of portable electric mine lamps. Although there is still need for better illumination in mines and the replacement of open lights has been slow, improvement in electric cap lamps and increase in their use indicate one phase of recent progress toward safer and more efficient mining This report is the result of a recent survey of electric-lamp installations in the Alabama mining; district; it shows the misuse, increase in use, and relation to certain classes of accidents of these installations.

Jan 1, 1935

By C. E. Rork

This paper discusses various mechanical improvements that have been gradually incorporated in the copper-willing plants of the Southwest daring the past 14 years, power plants for concentrators, use of large-size units of equipment, and the effect of plant capacities on costs. The improvements in mechanical equipment and plant design have contributed in the reduction of operating costs; in some instances a saving in the capital cost per ton of daily capacity milled has resulted.

Jan 1, 1935

By Oliver Bowles

This paper is the third of a series of reports on asbestos prepared by the Bureau of Mines. The reports already issued contain general information, including descriptions of deposits throughout the world.3/ The present paper deals chiefly with milling and marketing. Many grades of asbestos are marketed, and an important phase of milling is the grading of fiber; these subjects therefore are related so intimately that contiguity in their treatment is fully justified. Although the Bureau of Mines is interested primarily in the mining and preparation of raw materials, the fabrication of asbestos products has attained such importance in the United States that brief reference to processes of manufacture is included. CLASSIFICATION OF FIBER Canadian asbestos fibers are divided into three main groups - crudes, mill fibers, and shorts. The term "crude" is applied to fiber of spinning grade measuring three eighths inch or longer, that is. hand-cobbed and not passed through a mill. Mill fibers are obtained by crushing and beating the fiber-bearing" rock, until the, asbestos is freed and, then removing the fiber from the rock by screening or air separation. Shorts are the lowest grades of mill products.

Jan 1, 1935

By D. Harrington

The experience of the past 2 years has demonstrated clearly that mine explosions with heavy loss of life can be prevented. The investigations of the Safety Division of the United States Bureau of Mines disclose that during the fiscal year 1934 there were only 28 deaths from mine explosions in the United States, and during the fiscal year 1935 there were 54 deaths, a very favorable reduction when compared with an average death toll of 265 from this cause during the 20-year period prior to 1929. Although the frequency of occurrence of explosions has not decreased greatly during the past 7 years, there has been a marked decrease in severity, indicating that the coal-mining industry is taking more effective precautions to prevent the spread of explosions. A number of large coal-producing States, which in past years have experienced numerous disastrous explosions, have been free from such disasters for continuous periods of as much as 5 years or even longer. A study of several hundred mine explosions occurring in the United States during the past 10 years or more indicates that the factors mainly responsible for these explosions are inadequate or defective ventilation and disregard of the hazards from explosive gas. Both of these factors are subject to control, and if controlled it is safe to say that deaths from explosions would be reduced to a negligible number as relatively few explosions are now initiated by dust.

Jan 1, 1936

By D. Harrington

Probably over 95 percent of the coal production of the United States depends upon the use of explosives before it can be placed in the railroad car at the mine, and up to the present time it has been impossible to obtain Pry kind of practicable explosive that isn't dangerous unless handled carefully. In other words, no "foolproof" explosives have been found to date and inspection of the accident records of the coal mines of this country indicates that the use of explosives in coal mines has taken a sad toll of lives. ACCIDENTS PROM EXPLOSIVES IN COAL MATES Of the 2,000 to 2,500 persons killed annually in the coal mines if the United States, 100 to 125 have been killed from explosives without an explosion of gas or dust; these accidents have been due to misfires, hangfires, premature blasts, or accidental setting off of explosives through carelessness or otherwise (but chiefly through carelessness in some form). In this type of accident the flame character of the explosive is not necessarily involved, although an unexpected or premature blast is initiated much more easily with black blasting powder, which has a long flame, than with a permissible explosive, which has a flame much shorter and of briefer duration. By far the greater number of such accidents are caused by black blasting powder or dynamite rather than by permissible explosive.

Jan 1, 1936

By J. W. Paul

The United States Bureau of Mines has made a study of roof control in 68 mines operating in the Pittsburgh coal bed in Pennsylvania, West Virginia, and Ohio. In making these studies, much information was also obtained on various exact methods of development and pillar extraction as practiced by this large group of mines. It is proposed in this paper to describe these methods, by which this group of mines in 1931, a year of reduced industrial activity, produced 28,123,000 tons of bituminous coal - 7.4 percent of the national production for the same year and an amount equal to the combined production of the coal mired in the States of Alabama, Colorado, New Mexico, Utah, and Wyoming. The results of these studies, insofar as they pertain to the prevention of injuries from falls of roof, have been published by the Bureau of Mines. In this paper only a few mines typical of each system will be described; however, should the reader be interested in other details with respect to these mines, he may refer to the following publications: T.P. 522, 1932, 43 pp. Falls of roof and coal in mines operating in the Pittsburgh coal bed in Marion and Monongalia Counties, W. Va., by J. W. Paul and J. N. Geyer.- A study of nine mines in these two counties of northern West Virginia.

Jan 1, 1935

By William O. Vanderburg

The fluorescence of many minerals, when excited by different wave lengths, of ultraviolet radiation, has long been recognized as a spectacular laboratory phenomenon. Since the original display in the British Museum, the phenomenon has been used frequently for educational purposes and public demonstrations. Its practical application for the rapid detection of certain minerals in ores and mill products at the zinc mine at Franklin, N. J., has been described.3 Due to technical improvements in ultraviolet-radiation apparatus, fluorescence has found a new field of application in the tungsten-minim; industry. Although fluorescence of scheelite (calcium tungstate) has been known for a number of years, the practical application of the phenomenon is the outgrowth of a program of cooperative research conducted by Ott F. Heizer, manager of the Nevada-Massachusetts Co., Inc. , Mill City, Nev., and Dr. Paul F. Kerr of Columbia University. Special portable lights for fluorescing scheelite have been developed and utilized in underground geological work. Thanks are due Ott F. Heizer for permission to publish data included in this paper.

Jan 1, 1935

By J. R. Thoenen

This circular is part 5 of the third paper (entitled "Excavation") of a series summarizing the technical problems involved in the production and preparation of sand and gravel. Part 1 discussed the use of power shovels, draglines, and excavator cranes; part 2, power scrapers, slackline cable-way excavators, and hydraulic monitors; part 3, hydraulic, clamshell, ladder, and dipper dredges; and part 4, haulage systems in general, with particular reference to locomotive and car, hoist and car, and remote-control systems. This circular discusses the use of motor trucks, conveyor belts, pumps end pipe lines, barges and towboats, and aerial trams. MOTOR-TRUCK HAULAGE During recent years motor trucks have gained considerable ground as a successful competitor of locomotive haulage for quarries and gravel pits. Often where trucks have displaced locomotives and cars the operators readily admit an increase in both labor and total haulage operating costs but point to some other advantage as offsetting the extra expense. In other instances haulage costs have beep reduced by the use of trucks. In still others operators, having replaced locomotive haul with trucks, have again returned to the earlier method. Obviously gasoline-driven motor trucks cannot successfully compete with other types of haulage under all conditions. The apparent' growth in the number of advocates of truck haulage, however, indicates that it has passed the experimental stage and become a permanent competitor to other tyres.

Jan 1, 1936

By C. E. Julihn

In the past few years the advance of the Sunshine mine to national prominence as the chief silver-producing mine of the United States has revived interest in the area in which it is situated. Although this area lies between the great lead-Zinc-silver mines at Kellogg and those in the vicinity of Burke and Mullan it was generally presumed to be almost barren, as little ore had been found there until substantial ore bodies were developed on deep levels of the Sunshine mine. In early days it was called the "dry belt" because its ores were siliceous and contained little lead; but the classification of ores in smelting as wet or dry, although once customary, has long been obsolete The area will therefore be referred to in this paper as the silver belt of the Coeur d'Alene district because the value of its ore is due chiefly to silver, the current production of which is large, providing over 60 percent of the silver output of Idaho. Silver Belt - Its Limits and Character With a daily production of half a ten of silver or more from the Sunshine mine, the silver belt has become the scene of extensive exploration at many properties, and the outlook for its future seems promising enough to warrant the lively interest now being displayed in the area by the public.

Jan 1, 1936