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By James R. Finlay

SOMETIMES the American Institute of Mining and Metallurgical Engineers appears to be a strictly technical society, and if so my paper should deal with the technical operations of finding and producing gold. But I have not been engaged in practical gold mining since 1910. What I have been doing mainly for the last 25 years is to try to figure out what the income of a mine-gold, or any other-would be worth to an investor. So I have been in contact with gold mining, in one way or another, for some 42 years. I say that with a purpose. In that time the industry has been through one of its cycles. The value of gold mines is very dif¬ferent at different points in one of these cycles. For this reason the cycle of gold mining is a highly practical study. The cycle of gold is a more or less rhythmical change in its value or purchasing power measured in the grand average of other commodities, which is the same thing as its price. Taking the price of gold in 1897 as a stand¬ard, a dollar at that time declined to 55c. in 1913, to 26.8c. in 1920, and since then it has risen to 47.4c. in 1930 and to about 64c. in 1932. It is worth about 21/ times as much now as it was in 1920, but less than two¬thirds as much as in 1897. When this change is applied to the value of a gold mine still greater differences are evident. The cost of producing gold is of course measured in labor and other commodities, and as that cost goes down the margin of profit measured in the gold itself increases. Thus a mine which might make only 10 per cent profit in 1920 on its gross output may easily make 25 per cent now. The stockholder gets 2 ½ times more gold that is worth 2 1/2 times as much in purchasing power, therefore the real value of his holding has risen by the one factor multiplied by the other, giving him 61/4 times as much goods or services as he had in 1920.

Jan 1, 1933

By Clyde L. Holmberg, Paul Zinner

"INTRODUCTION In view of the large tonnage of low-grade iron ore and iron-bearing material known to exist at the western limits of the Gogebic range, the Bureau of Mines undertook an investigation of the area for the purpose of evaluating the iron-bearing formations as sources of iron for possible future utilization.After 6o years of exploration an, development on the Gogebic range, the area investigated by the Bureau represents the known western limit of direct-shipping ore mined from operations on the Gogebic range.An area about 2 miles in length between the villages of Pence and Iron Bolt in Iron County, Vic., was selected for investigation, and trenches wore excavated through the overburden and fully across the iron-bearing formation to obtain 108 bulk samples for beneficiation tests. Exhaustive tests involving gravity and flotation methods, magnetic separation, and magnetizing roasts followed by magnetic separation were conducted on the samples to determine the ammability of the individual formations and the entire iron-bearing zone to beneficiation.Empirical data on the character and mineral content of the formations arc tabulated herein, as well as the results of the beneficiation tests."

Dec 1, 1947

By AIME AIME

BESIDES commanding increasing importance as an alloying element in combination with ferrous and other nonferrous metals, the variety of uses for pure nickel continues to widen. For coinage it is growing in popularity. These coins have been minted for 27 countries in 72 issues representing 69 denominations. Approximately 3,000,000,000 pieces have been struck, the aggregate weight, of which amounts to nearly 14,000 tons. . Danzig, Iraq and Japan are the most recent governments to adopt, pure nickel coinage. France is adding the denomination of five francs to its other nickel currency; they replace silver pieces. Germany is now minting a new issue of one Reichsmark coins of pure nickel. The Japanese program for 1933 called for the issue of 35,000,000 10-sen pieces and 30,000,000 5-sen pieces. In radio tube manufacture the consumption of pure nickel was approximately twice that of 1932. During 1.933 the nickel plating process by which bright deposits may be plated

Jan 1, 1934

By Donald A. Brobst

Barite, the sulfate of barium, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. The commercial deposits of barite may be classified into three major types. 1. Vein and cavity fillings that occur in rock fractures, along bedding planes, and in various solution structures. 2. Bedded deposits in which barite occurs as the principal mineral or cementing agent in stratiform bodies in sedimentary rocks. 3. Residual deposits occurring in unconsolidated material formed by the weathering of preexisting rocks. The geologic characteristics of each type of deposit are of fundamental importance to the successful search, development, and economic use of barite deposits.

Jan 1, 1980

By Alfred W. G. Wilson

THE ultimate purpose of the Chemical Manufacturer is to produce consumer products which can be sold to customers. Such production and sales can be continued only if the operations yield a profit to the manufacturer and if the products meet the requirements o the consumer--bath parties to the transaction must be satisfied. There are vast numbers of consumer products, made by chemical pro-cesses. The production of some of these ultimate products may involve the use of several intermediate chemicals, applications of few or many different processes, and the utilization, somewhere in the series of operations, of a variety of raw materials. On the other hand, some ultimate products have a very simple chemical history between raw materials and end products. There are no chemical products in use which are completely independent of the mineral industry. For many, the association is direct and obvious; for others, it may be indirect and even obscure. Analyses of the process and raw-material ancestry of a very large number of consumer products would suggest that many products are derived from Industrial Mineral products directly, that there are many in which the connection is indirect, and that there are only a few products with which industrial minerals are not in some way or other associated. The vast majority of the more important chemical products, and especially the basic chemicals from which other products are made, are directly dependent for their production upon Industrial Minerals or their derivatives. In the preceding part of this paper, for each raw material mentioned some references have been made to the leading chemical products based on this material. This, however, is only part of the story, because in most cases the consumer product can be made from any special raw material mentioned only by the use of other materials or chemicals made from them. The production of consumer chemicals is really possible only through an intricate interlocking of processes, materials, and apparatus.

Jan 1, 1940

By H. Reimer

The rates of return on investment are examined for several major Canadian mining companies. Because we are dealing with a highly cyclical industry, subjected to widely fluctuating metal prices, rates of return are examined over a 20-year period. Conveniently, the first decade examined reflects the period when the industry enjoyed incentives to develop deposits; during the second decade, incentives were reduced and the industry became the most heavily taxed industry in Canada. The high rates of inflation since 1973 have distorted the real rates of return on investment if one considers replacement cost.

Jan 1, 1977

By J. S. Hansen

To advance technology that can conserve critical materials, the Bureau of Mines investigated a cast-on hard-surfacing that wear resistance and confines alloy additions to wear-prone surfaces. Wear-resistant material in form is on a polystyrene , the is embedded in a mold of unbonded s and the wear-resistant material is transferred to a cas surface at the time of For low-stress abrasion, derived from high-carbon ferro-chrome had higher wear resistance than did commercially available weld-hard. The microstructure of the was typi-white iron carbides. Free carbon added to the ferrochrome powder produced more M7C3 carbides than did material contained in surfacings made from ferrochrome alone, and improved the wear resistance. Several white iron powders with greatly reduced chromium contents also white iron contain-M7C3 carbides. One derived from white iron powder had wear resistance to that of weld-deposited hard facings. Among the parameters investigated, surfacing thickness was found to have a or influence on diffusion of elements out of the , microstructure, and wear resistance. The results of field tests on bucket-wheel excavator teeth and plowshares with cast-on hard surfacing are given.

Jan 1, 1985

By P. R. Bradley

This paper is one of a series , dealing with mining methods and costs , sponsored and published by the U. S. Bureau of Mines . Papers of this series are written by engineers and executives of mining companies , at the solicitation of the Bureau , and in accordance with an outline prepared by Bureau engineers , for the purpose of securing uniform presentation and conformable data . The property of the Alaska Juneau Gold Mining Co. is situated near the city of Juneau , Alaska , in what is known as the Harris mining district . Wholesale mining operations have been adopted on a large scale and 10,000 to 11,000 tons per day of gold- bearing ore are mined and sent to concentrators near Juneau . In addition to gold , the ore yields 0.6 ounce of silver and 13.0 pounds of lead to each ounce of gold recovered .

Oct 1, 1929

By Joseph Kuti

Longwall mining is the term used for the underground extraction of a wide and deep panel of coal. Such a panel may be blocked out by one or more entries on either side ("head" and "tail") of a longwall face. If all the entries are pre-driven, the panel extraction is termed longwall retreat mining. With one exception, all the longwall faces in the United States are of this type. (1) prior to the general decline in the rates of production with Continuous Miners, the development of the multiple entries generally kept ahead of the longwall extraction rate. This is no longer the case: longwall extraction rates far exceed the rate of development. In addition to this problem, in newly established mines, the development of a haulage and bleeder system based on multiple entries results in a lead-time of three years or more before longwall mining can be applied. This is one reason why earlier projections and much of the optimism attached to longwall mining as a principal "savior" in the energy crisis should be viewed with some caution.

Jan 1, 1978

By Sean Gallagher

This report was written in an effort to provide better control measures for low back pain (LBP) and low back disability in the mining industry. There are numerous factors associated with development of LBP, many of which can be effectively controlled while some cannot. Better job design is promoted as the best method of reducing cases of LBP and can also reduce the disability (i.e., lost time from work) associated with LBP when it happens. The report draws attention to what is currently known about LBP, what the causes are thought to be, and discusses recent back injury trends in the mining industry. Research describing unique physical demands in mining, such as the capabilities and limitations of working in awkward postures, is also presented. Methods that can be used to prevent initial LBP episodes are provided, including facilities design and layout for materials and supplies, use of mechanical-assist devices, improved design of lifting tasks, and better seat design. Methods of reducing the disability associated with LBP (including workplace design, proactive return-to-work efforts, communication, and management commitment) are also discussed. The report concludes that control of LBP and disability in mining requires a comprehensive approach to limit the repetitive loading that can occur on the low back due to manual materials-handling tasks and exposure to whole-body vibration (WBV). Specific recommendations include the following: ? Successful LBP prevention efforts require a proactive program that has strong management commitment and incorporates employee involvement. ? More efficient supply handling systems and use of mechanical-assist devices can greatly reduce exposure to hazardous lifting tasks. ? Lifting tasks should be designed to minimize low back stress. Tools to evaluate and redesign lifting tasks are presented. ? Improved seat design can reduce exposure to WBV and improve posture, leading to reduced LBP risk. ? The disability associated with LBP can be reduced. Getting the worker back on the job as quickly as possible is in the interest of everyone involved.

Sep 1, 2008

By Jos. R. Guiteras

This is one of a series of information circulars describing mining and milling methods being published by the Bureau of Mines. The Summitville Consolidated Mines, Inc., is the only company now active at Summitville. Since the holdings of the company include those of most of the former producers of the camp, the paper virtually becomes a description of the Summitville district. The field data were collected from August 23 to 28, 1937. ACKNOWLEDGMENTS The writer gratefully acknowledges his indebtedness to H. F. Detrick, president, and Edward Thornton, general manager of the company for their cooperation in making this paper possible. Most of the information on underground operations was given by Roy Jellison, mine superintendent; the metallurgical data were supplied by Art Carl son, metallurgist, and W. L. Anderson, mill superintendent; much general and technical information was supplied by J. H. Hannan, engineer.

Jan 1, 1938

By E. G. King

The Bureau of Mines made experimental determinations of the heats of formation of forsterite and chrysotile at 298.15° K. The heat capacities of two polymorphs of serpentine, chrysotile and antigorite, were measured over the temperature range from 50° to 298° K and the entropies at 298.15° K were evaluated. The heat content of antigorite above 298.15° K was measured to 850° K. These thermochemical data were combined with other pertinent data to give heat and free energy of formation values at high temperatures. Free energy values are given for the reaction, forsterite + water = brucite + serpentine at different temperatures and pressures.

Jan 1, 1967

INTERNATIONAL conferences on safety in mines originated in 1912 when, in response to an invitation issued by the United States, representatives of Austria-Hungary, Belgium, France, and Germany participated in a conference held in Pittsburgh, Pa The record shows that a permanent organization was proposed to be developed through. diplomatic channels. However, the advent of war 2 years later prevented this proposal from coming to fruition. No further cooperation between the Bureau of Mines and a group having: similar interests in a foreign country took place until 1924, when formal cooperation with the Safety in Mines Research Board of Great Britain was established. Interchange of personnel and results of research under that arrangement have resulted in a number of publications in both countries and more rapid advance in knowledge than could have been obtained through the same efforts exerted independently.

Jan 1, 1950

This Workshop was held at the Doubletree Inn, Seattle, Washington from September 26 to 28, 1997. Run under the auspices of the Deep Foundations Institute (DFI), it was co-funded by the newly formed Japanese Association of Micropiles (JAMP), and the Federal Highway Administration (FHWA). The Workshop was jointly organized and facilitated by Fujita Research Corporation and ECO Geosystems, Inc., with close support by Donald B. Murphy Contractors, Inc. DFI kindly consented to publish these Proceedings. As is clear from the list of attendees, 42 specially invited engineers from all aspects of micropile technology were present, representing Japanese, European and American practice. This proved to be a most friendly and interactive group of people, who freely exchanged ideas, views and close comradeship, not only during the technical sessions, but (and especially!) during the numerous social events. Perhaps the best illustration of this came in Day 2 when the attendees were divided into five competing teams, each comprising representatives from the different geographic groupings. These teams had to quickly devise solutions to two technical problems (using standard data previously provided. A team of "referees" (who also acted as "coaches") later determined the most apposite response, based on constructability design concept, cost, schedule and so on. Not only were the winning team very liberal in distributing the prize (vintage California champagne) among themselves, but the whole Workshop soon benefited from their generous division of the spoils of victory.

Jan 1, 1997

By T. C. Moore

This report describes the feasibility test of an electromagnetic method for locating boreholes, with or without casing, that have been drilled in conjunction with mining operations but whose location with respect to the tunnel is not precisely known. The first tests were conducted with the cooperation of the Kerr-McGee Corporation, Church Rock Mining Operations, New Mexico, in September 1977. These tests demonstrated that accuracies of better than ±5% of range and ±1° of bearing can be achieved with a simple system and setups. Subsequent tests, in January 1978, on a horizontally drilled pipe line river crossing application, by Titan Contractors of Sacramento, California, demonstrated that accuracies of better than one-half percent of range and a few tenths of one degree of bearing can be achieved by using refined techniques. The demonstration tests were done at ranges on the order of 100 to 200 feet but the method is capable of working at much greater distances.

Jan 1, 1978

Mine waste and mine reclamation are topics of major interest to the mining industry, the government and the general public. This publication and its companion volume are the proceedings of a conference held in Pittsburgh, April 19-21, 1988. There were nine sessions (50 papers) that dealt with the geochemistry, hydrology and problems of mine waste and mine water, especially acid mine drainage. These comprise Volume 1. The nine sessions (43 papers) that dealt with reclamation and restoration of disturbed lands, as well as related policy issues, are included in volume 2. Volume 2 also contains the ten papers that pertained to control of subsidence and mine fires at abandoned mines. Poster session presentations are, in general, represented by abstracts; these have been placed in the back of both volumes.

Jan 1, 1988

By Joseph M. Kurtak

The Bureau of Mines conducted a four year (1985-1988) mineral assessment of the Juneau Mining District in southeast Alaska as part of its ongoing statewide mining district evaluation program. Following an extensive literature search, the Bureau investigated mines, prospects, and mineral occurrences in the area. This report describes the results of Bureau work in the Eagle River area of the Juneau gold belt; a component of the Juneau Mining District comprising 87,000 acres between the Mendenhall Glacier and Berners Bay. Gold and silver have been the only metals having significant production from the area and occur mainly in quartz stringer and fissure type veins hosted by phyllites, greenschists, greenstones, altered diorite dikes and quartz diorite gneiss. Gold also occurs in several small placer deposits. Approximately 21,100 oz of gold and nearly 9,000 oz of silver were produced over a 60 year period. Currently, the only mining activity consists of some exploration and minor placer gold production. Inferred and indicated lode gold resources having mineral development potential total approximately 796,000 tons with a weighted average grade of 0.22 oz/ton gold.

Jan 1, 2011

By B. van Beek, J. Ndlovu, K. T. Hara, J. M. A. Geldenhuis

This paper describes the development of an alternative technique for measuring the matte level height in sulphide smelting furnaces. The initial studies involved applying electrochemical oxygen probes in a smelting furnace to measure the oxygen potentials of the matte and slag phases. However, these measurements were not successful as a result of low temperatures, preventing there ference electrode from attaining equilibrium during the measurements. These trials were followed up by using oxygen probes containing a (Mo + MoO2) reference electrode instead of the(Cr + Cr2O3) reference electrode used previously. It was shown that with some further development work, it should be possible to measure the oxygen potential of these mattes accurately. Further measurements were performed with a magnetic sensor in sulphide mattes. It was shown that an electronic signal, which is proportional to the magnetic susceptibility of the surrounding material, was generated during immersion into liquid matte. These measurements were extended and done in a smelting furnace. Initial results indicated that when the magnetic sensor was dipped through the slag layer into the matte, a signal was generated as soon as the sensor came in contact with the matte. Measurements are ongoing in order to record (on a computer for improved accuracy) the signal as a function of distance when the sensor is immersed through the slag layer into the matte phase. The magnetic sensor measurements may be the solution to a matte level measurement problem that has existed for a few decades in matte smelting furnaces.

Jan 1, 2004

By William E. Souder

The behavioral accident simulator (BAS) is a computer program that can be used to simulate accident situations. It demonstrates how the potential to have an accident grows or diminishes as a result of changes in various environmental, organizational, and behavioral factors. It calculates the number of fatalities that may result from various conditions and graphically displays these data. The BAS is useful for studying systems of accident causes, for demonstrating the various ways to diminish fatalities, and for training employees. This Bureau of Mines report provides the detailed instructions needed to use the BAS.

Jan 1, 1988

By A. Eltringham

Operations downstream of mining and beneficiation are still being subjected to increasing scrutiny as highly capitalized projects have been either slow to achieve their targets or have actually failed to do so. Leaching and smelting projects have fundamentally high calls on capital and technology as reaction rates are increased and the capture and disposal of unwanted products are subjected to greater restrictions. Separating value from waste inherently becomes riskier as the purification of the desired product imposes greater demands on the process to produce benign wastes. When we superimpose on the chemistry of the project severe predictions of throughput rates, that bring in facets of manufacturing, we are introducing complexities that the records show are not handled well. This paper discusses some of the more common challenges that operators face and what methods are available and are likely to be successful in preventing the loss of value as projects are brought on-stream. This thinking needs to start much earlier and at greater intensity than our industry has normally chosen to employ.

Jan 1, 2011