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By O. T. Berge

Development and production from open cut mines continued its vigorous growth trend during the year 1968. Material handling and transportation were again exposed to the use of larger equipment with shovels, trucks and front end loaders leading the way. Highlights of World Mining Activities Africa: The Anglo American Corp. opened a new high-grade copper mine in Zambia during the year. In Angola, the Companhia Minera do Lobita planned a 3 million ton iron ore production for 1968 from new mines which will ultimately produce 5 million tons per year. A feasibility study of Bethlehem Steel Co., for the development of large high- grade iron ore reserves in Gabon, was in final stages of completion this year and Pickands Mather and Co. continued its investigation of iron ore deposits along the Ivory Coast.

Jan 2, 1969

Remarks of Mr. Robert W. Hunt, General, Superintendent, Albany and Rensselaer Iron and Steel Company., Troy N. Y.—In discussing Dr. Dudley's two most interesting papers, I feel a natural hesitancy in disagreeing with conclusions formed after such careful and conscientious work. But I think he has made his deductions from too meagre premises. The analyses of but twenty-five samples are entirely too few to justify the establishment of so important a formula. When we consider that he indirectly proposes to regulate an interest amounting, even at the present low prices, to over $20,000,000 per annum, we may well hesitate before accepting a formula based upon the chemical and physical analyses of but twenty-five steel rails. Dr. Dudley touches the keynote in referring to the proposed labors of the Government Test Commission. They based their hopes of attaining success upon the chemical and physical analyses of a very large number of samples, and in the only branch of investigation which the short-sighted policy of Congress has allowed them to complete, i.e., chain cables, we find that a dozen, twenty-five or one hundred tests gave no satisfactory results. It was only after many hundreds that they were enabled to' draw conclusions. There are so many circumstances hearing upon the life of a rail, that the task of extracting a correct result seems herculean. I presume I am right in stating that in our Northern latitudes early winter and spring months witness the breaking of the greatest number of rails, thus seeming to prove that an unstable road-bed has much to answer for. Then, again, broken and flattened wheels must be taken into account, but I am convinced that more rails have been broken by the treatment which they received before leaving the rolling-mill

Jan 1, 1879

Remarks Of Mr. Robert W. Hunt, General Superintendent, Albany And Rensselaer Iron And Steel Company., Troy N. Y. - In discussing Dr. Dudley's two most interesting papers, I feel a natural hesitancy in disagreeing with conclusions formed after such careful and conscientious work. But I think he has made his deductions from too meagre premises. The analyses of but twenty-five samples are entirely too few to justify the establishment of so important a formula. When we consider that he indirectly proposes to regulate an interest amounting, even at the present low prices, to over $20,000,000 per annum, we may well hesitate before accepting a formula based upon the chemical and physical analyses of but twenty-five steel rails. Dr. Dudley touches the keynote in referring to the proposed labors of the Government Test Commission. They based their hopes of attaining success upon the chemical and physical analyses of a very large number of samples, and in the only branch of investigation which the short-sighted policy of Congress has allowed them to complete, i.e., chain cables, we find that a dozen, twenty-five or one hundred tests gave no satisfactory results. It was only after many hundreds that they were enabled to draw conclusions. There are so many circumstances bearing upon the life of a rail, that the task of extracting a correct result seems herculean. I presume I am right in stating that in our Northern latitudes early winter and spring months witness the breaking of the greatest number of rails, thus seeming to prove that an unstable road-bed has much to answer for. Then, again, broken and flattened wheels must be taken into account, but I am convinced that more rails have been broken by the treatment which they received before leaving the rolling-mill * The remarks of the participants in this debate have been written out by the speakers, and are here given without any attempt to retain the order of the dis¬cussion. While the report does not, therefore, preserve the vigor and spontaneity of the debate, it is believed that it gains in value by giving the matured views of the speakers. The continuation of this discussion at the Pittsburgh Meeting, May, 1879 (beginning with remarks of Mr. Cloud on page 401), is appended for convenience of reference.-T. M. D., Sec'y

Jan 1, 1879

By H. W. Gillett, E. L. Mack

"This report describes the trend of developments in electric brass-furnace practice in the last two years, and supplements Bureau of Mines Bulletin 202, ""Electric Brass-Furnace Practice"", which was published in 1922. In that bulletin it -as pointed out that some of the lines on which electric brass-furnace progress would take place were clear, but others were less so.Developments in foreign countries.Foreign brass-melters have not yet adopted electric melting to an extent comparable to its use in the United States. It is doubtful Whether all foreign countries combined use 100 electric brass furnaces; of these about 35 are of American make (Ajax, Detroit, Baily) and are operating in Canada, Mexico, England, France, Japan, Sweden, Switzerland, Spain, Norway, Germany, Argentina and Czecho-Slovakia.`The Rennerfelt furnace finds some use in Sweden (1)c, notwithstanding its high metal loss on alloys high in zinc, Two German firms are reported(2) to be using the Rochling-Rodenhauser induction furnace on bronze, the average energy consumption being given as 400 kw.-h. per ton. No comment is made on any trouble from the ""pinch effect"", A firm in Switzerland is reported (3) to use three 600-lb., direct-arc furnaces of its own design to melt babbitt, antimonial lead, coinage silver, nickel, copper, and brass. The metal loss on yellow-brass turnings is high. Use Of a direct-arc furnace in England, with precautions aimed to prevent surface overheating, vas abandoned (4) in favor of an Ajax furnace."

Apr 1, 1924

By D. Morgan Warren, David Hanson, Alice Alex, Tom Meuzelaar, Heather Lawson, Sam J. S. Wright

Dynamic coal failure events remain a safety concern in underground coal mining due to their sudden nature and high fatality rate. Previous research utilized Principal Component Analysis on field samples revealing strong empirical correlations between positive failure history and low sulfur content (S) and high volatile matter (VM). Further studies indicated that bumping coals tend to be less mature and less well-cleated than non-failure coals. However, these in situ studies faced the challenge of distinguishing intrinsic coal properties from external geological and stress-related influences. This study augments previous findings through laboratory experimental testing of coal samples that included unconfined compressive strength, chemical composition analysis, and qualitative observations on cleating, combined with compositional data analysis and machine learning techniques, to isolate and understand coal’s inherent bursting capacity. These results further confirmed the relationship between coal chemistry and failure classification.

Feb 22, 2026

By Herbert H. Einstein

Rock mass deformability is commonly predicted using correlations with RQD or other indices of rock mass quality, or by extrapolation from large in-situ tests. Based on the probabilistic description of rock masses empirically developed in Part I a new approach was attempted in modeling for predictions of deformability. This approach decomposes the rock mass into spatially variable joints described by probability distributions, and intact rock blocks. Stiffnesses and elastic parameters are associated with the joints and intact blocks respectively, and deformations built up by adding the contributions of each. This model allows relaxation of many of the simplistic geometric assumptions which constrain parallel attempts to model deformation in rock masses. The model has been applied to four standard cases in order to test its results against previously existing models, and to check whether it replicates empirical correlations. When joints are taken as parallel, common empirical correlations are closely approximated by the model output. However, the closeness to empirical correlation breaks down when variability of the jointing geometry is increased.

Jan 1, 1979

By J. W. Paul

The material that composes the roof in coal mines differs in strength according to variations in its physical nature and characteristics. Some material such as limestone and massive sandstone, (free from slits) and carbonaceous shale or bone, will often remain in place in narrow work without the use of timber or other means of support, but in wide places the use of supports becomes a real necessity. Roof material composed of shale, fire clay or small laminations of sandstone, or shale or sandstone interspersed with laminations of thin coal, presents conditions that call for timber support in both narrow and wide work. However, in narrow work such unstable roof material may be taken down until the strata assume an arch that is self-supporting for overlying firm strata such as a roof coal, a touch weather-resisting, shale, sandstone, or limestone. The proper support of the roof in roadways used for haulage or travel adds to the economy of operation by preventing delays in transportation and increases the safety of those who travel these roadways.

Jan 1, 1930

By Radhe Krishna, Mutale William Chanda, Timothy Mwale

Blasting as a process is the emplacement of industrial explosives into blast holes suitably located to a free surface and detonated. Every blast hole containing a certain amount of explosive charge undergoes impulsive loading when detonated and results in the dynamic transfer of a powerful shock wave to the surrounding rock. It is the shock wave that brings about rock breakage when the tensile stress produced upon reflecting from the change in material density or free face overcomes that of rock material tensile strength. However, this shock wave comes along with unwanted destructive consequences such as damage to remaining rock, ground vibration, noise and fly rock. The above mentioned consequences pose a great threat to the Community of Wusakile, Kitwe as Mopani Copper Mines Plc wishes to increase its production by expanding the pit towards the community that lies within 150 m (164 yd) from the pit rim. As a requirement from the Zambia Environmental Management Agency (ZEMA), all blasting operations close to the community must maintain at least below the maximum vibration threshold of 10 mm/s (0.3937 in/s) PPV-Peak Particle Velocity or else risk closure of the mine (AMC,2009). In order to satisfy the above statement, a good understanding of explosives is required. This paper therefore presents the phenomenology of rock breakage by explosives with much emphasis on electronic blasting and how best this process can be controlled in densely populated communities. Factors affecting maximum projection distance such as, size of the fragment, shape of the fragment, angle of projection, the state of confinement of an explosive charge, were also studied. In addition, design faults, deviation in implementation and unforeseen geological conditions were also considered. The paper discusses the above facts based on research.

Jan 1, 2015

By Krishna Parameswaran

"This paper discusses energy use and conservation in the primary copper industry and illustrates eco-efficiency considerations, using select examples of practices at ASARCO LLC, an integrated primary copper producer and others in the industry that promote eco-efficiency. The World Council for Sustainable Business Development first publicized the concept of eco-efficiency at the Rio Earth Summit in 1992. Eco-efficiency is a management concept linking environmental and economic performance and is aimed at generating added value for a business through, among other things, increased resource and energy conservation and reduced environmental impacts throughout the life cycle of the product or service. This concept differs from sustainable development in that focus is only on economic and environmental factors and does not include social considerations. In the metal mining and processing context, this added value can be realized by implementing practices that promote conservation of water and mineral resources, conservation of energy, minimization of waste, reduced emissions and effluents and increased recycling. The examples from the primary copper industry used to illustrate eco-efficiency considerations include: water and energy conservation in mineral processing, adoption of flash and bath smelting processes, emission reduction and process improvement associated with fire-refining, implementation of green chemistry in electrorefining, promoting product stewardship initiatives and fostering renewable energy project on disturbed mined lands.INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting And Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co-products. Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills, two leach, solvent extraction-electrowinning (SX-EW) plants and a copper smelter in Arizona and a copper refinery in Texas."

Jan 1, 2017

By C. A. Komar

The Bureau of Mines is investigating possible applications of acoustic energy at sonic and ultrasonic frequencies in petroleum production. A phase of this work involves measuring sound velocity through petroleum reservoir rocks. References and abstracts were prepared as a bibliography to make available to others some of the material obtained from a literature search covering the past applications and the present uses of sound. Laboratory and theoretical studies of the various parameters that influence the velocity of sound in porous media account for the wealth of information now available. Velocity of propagation of sound waves in porous sediments as a function of depth is a quantity frequently measured. Velocity logging systems, capable of measuring speed of sound waves in underground formations penetrated by wells, have been developed for interpretative studies. The close relation between acoustic velocity and porosity makes it possible to determine porosity from velocity logs. Most velocity log interpretation in terms of porosity is based on a formula developed by Wyllie and others known as the time-average relation.

Jan 1, 1963

By Mukhopadhaya K. K, Cory A. H

The concept of using travelling magnetic fields created by linear motors was stimulated by Laithwaite who advanced ideas on motors with shaded poles (Laithwaite, 1968), rack and pinion motors (Laithwaite, 1970) as well as low speed, brushless motors and three dimensional motors (Laithwaite, 1973a and 1973b).Sudan (1963) and Sundberg (1969) had applied the concept to metallurgical processes. However, the use of travelling magnetic fields has not been used widely to produce conditions for the separation of magnetic from non-magnetic minera1s or even magnetic materials from non-magnetic materials, although some attempts were made by McCarthy (1922), Davis (1934), Dean, Gottschalk and Davis (1934) and Gottschalk (1934).Laithwaite (1973, a) while working with linear motors made suggestions for designing separators and in the work described here, the observations of Laithwaite and others are extended to determine the characteristics of the motor with a view to using it as a magnetic separator.

Jan 1, 1980

By K C. Williams, A W. Roberts, J D. Prigge

For stockpile design, the flowability and structural interfaces are critically dependant on the stress conditions throughout the pile. Historically, the predictive methodologies for stress determination have been too conservative, which adds inefficiency to the stockpile reclaim interface selections, especially for live reclaim stockpile systems. In addition, accurate pressure profiling throughout stockpile is essential to correctly design the stockpile support structures, which are buried within the stockpile. Such buried structures include trestle legs or columns to support load-out conveyors or the roof of bulk storage sheds. Improved methodologies with respect to the development of the hoop stress condition which exists in material ædrawn-downÆ within the stockpile has been developed. This hoop stress approach has significantly improved the live capacity prediction to over 90 per cent accuracy and improved rathole structure prediction within live reclaim stockpiles. Additionally the methodologies in estimating the vertical and circumferential stress variation acting on buried stockpile structures have been significantly progressed, with experimental testing shown good agreement with the theory.CITATION:Williams, K C, Roberts, A W and Prigge, J D, 2013. Recent developments in stress analysis and live reclaim prediction within iron ore stockpiles, in Proceedings Iron Ore 2013 , pp 501-510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By I. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of Papua, Indonesia. This district consists of underground and surface operations. The East Ertsberg skarn system (EESS) is one of the major orebodies in this district. Subsurface caving of the EESS has been carried out in a systematic series of mining lifts dating back almost 30 years. Present production from the third lift deep ore zone (DOZ), has reached 80 kt/d (88,000 stpd) during 2010, with this rate sustained through 2015. The orebody was proven below the existing caving level, with the next vertical block called the deep mill level zone (DMLZ).

Jan 1, 2010

By Bernard H. Hertlein

"When the Deep Foundations Institute (DFI) was founded, quality assurance and quality control (QA/QC) of foundation construction was rudimentary. Nondestructive testing (NDT) was a nascent technology, known to very few people, and very limited in its capabilities and applications. In the four decades since the DFI became a reality, NDT researchers and practitioners have taken advantage of technological advances to improve those existing testing and analysis techniques, and to create new ones that have all contributed to the engineering body of knowledge. This has enabled contractors to improve the quality and reliability of their products, and engineers to design more efficient foundations.Through its regular series of seminars, publications and annual meetings, the DFI has been vitally important in educating the deep foundations industry about the capabilities and benefits of NDT methods. In turn, NDT results have helped the industry identify problems in deep foundation construction, determine the causes of those problems, and improve design constructability and construction practices to increase the quality, reliability and efficiency of all types of deep foundations. This presentation reviews the evolution of several important NDT methods, and the contributions that they have made to foundation quality.THE BEGINNINGSThe Deep Foundations Institute (DFI) was incorporated in 1976 in the State of New Jersey as a 501(c)(6) non-profit association. The DFI is a consensus organization of Contractors, Engineers, Owners and Suppliers involved with the design and construction of all types of deep foundations. The purpose of the DFI was and still is to improve the planning, design and construction of deep foundations by educating all those involved, sharing best practices, and promoting the adoption of new technologies that improve quality, productivity or safety.This is well expressed in the current DFI Mission Statement: To bring together multi-disciplined individuals and organizations to find common ground and create a shared vision and a consensus voice for continual advancement in the deep foundations industry.At the time the DFI was born, nondestructive testing for verifying the quality and integrity of deep foundations was in its infancy, its growth constrained by the technology, or lack thereof. Some visionary engineers of the time understood the physics of the potential methods, and therefore the possible capabilities, but were frustrated by the lack of technology to work with. Electronic equipment was mostly analog, and the few digital data acquisition systems that were available had such slow sampling rates that they were incapable of recording rapid event sequences or short duration events such as those used in modern integrity tests. For example, Jean Paquet, a leading research engineer at the French National Construction Institute, (Centre Experimentale de Recherche et d’Etudes du Batiment et des Travaux Publics, or CEBTP) patented the frequency-based analysis procedure for the Transient Dynamic Response (TDR) method, aka Sonic Mobility or Impulse Response, in 1974, but it was not until 1977 that analog data acquisition systems became fast enough to turn his theory into a reality."

Jan 1, 2017

By P. Somasundaran, Tarun Bhambhani, S. Murthy Khandrika, Partha Patra, D. Nagaraj

Fine and ultrafine mineral particles, particularly if, altered mineralogically, can have detrimental effects on selective separation of minerals. Behaviour of altered mineral fines has been investigated in this work by studying the effects of weathered silicate slimes on the selective separation of copper minerals, particularly with focues on effect of the pulp rheological behaviour, which plays a governing role in the process. Physicochemical properties of these altered silicates fines such as morphology and surface charge are proposed to be responsible for the adverse rheological effects and resultant selective separation. Here, the effect of a number of problematic aspects such as water chemistry, froth stability, physicochemical aspects of gangue mineral aggregates on flotation sub-processes has been studied. Processing problems owing to the physical aspects of the gangue minerals, shape and morphology, are primarily due to uncharacteristic increase in the pulp viscosity. While problematic aspects other than impact of pulp rheological behaviour can interfere with each other in their contributions to how they affect the sub-processes, effects owing to pulp rheological behaviour have a direct impact on the flotation performance. Subtle increase in pulp viscosity can interfere with sub-processes in flotation leading to decrease in recovery and grade, and it is difficult to assess the effects due to such subtle changes. Reagent based strategies to overcome the problematic aspects has been explored here.

Jan 1, 2014

By Charles Hart

In this paper it is the author's intention to show the extent and character of foreign ores now known to be available; these deposits may be in active production or held in reserve until economic conditions may make them active. He hopes to show the relation existing between these ores and the American supply, and which of the former are now producing or will in turn come into production when our better ores have been exhausted. This phase of this discussion must of necessity include some data as to the present rate of consumption and a study of the changes we may expect here and abroad in the general steel trade and its sources of supply in raw materials. It is obvious that the occurrence of coal, ore and limestone in relation to one another and the proximity of a market are the elements in control of this feature of the problem. If the foregoing situation is favorable, all the other questions may be solved, for it is clear that with proper basic conditions finance, labor and operations will fall in line. We present a short outline of the present methods of carrying on the foreign iron ore trade, believing that it is of general interest in comparison with our own highly specialized methods, and that with the exhaustion of our better ores we will be compelled to seek a part of our supply abroad. A partial list of iron ores, with incomplete analyses (Table I), is added, to give a better understanding of the general situation and explain to some extent the reason for things being as they are in the iron and steel trade of the world and to help in bringing this paper to an informing conclusion. The question of the world supply of iron ores has been a subject for study on the part of geologists and engineers for many years, and found its best results in the Eleventh International Geological Congress, appropriately held at Stockholm, Sweden, in 1910. The proceedings are published in two volumes and are undoubtedly the best records available on this subject at the date of publication. It should be borne in mind, however, that much has happened in the 20 years since these figures were assembled. There is just as much known ore at present as at that time, minus the quantity consumed, plus newly discovered reserves. The World War had great effect upon this situation; during that time explorations were greatly reduced and the settlements after the

Jan 1, 1929

By M. C. Malamphy

The report of work accomplished on the United States Bureau of Mines' bauxite project in Pulaski and Saline Counties, Ark., is presented in this volume and in a series of Reports of Investigations immediately following this volume. This first volume covers the project as a whole, whereas the subsequent volumes contain maps of local areas and deposits developed, together with logs of the drill holes and descriptions of the separate deposits. The Arkansas bauxite project was initiated in December 1941 and continued for 4 years. The first 5 months were spent in studying the problems presented and in geophysical exploration, Core drilling began in May 1942 and ended in May 1945. The project was one of the larger and more important of those undertaken by the Bureau of Mines for the purpose of developing domestic sources of supply of critical and strategic minerals necessary for National defense and for the successful waging of modern mechanized warfare. Some of the results of the Bureau's bauxite exploratory work have been made available to the public through the medium of press releases, transactions of technical societies, and government publications. More information has been supplied to government agencies upon request and to land owners and mine operators of the deposits concerned in the form of maps showing locations of all holes drilled on the property and logs with chemical analyses of' all cores recovered. In October 1946, the factual data were made avail-able to .the public in manuscript form in an-"open file" at the office of the State geologist, R. B. Foxhall, Little Rock, Ark., and at the office of the. Bureau of Mines in Washington. For the purpose of providing a background for the presentation of the factual data obtained, the history of bauxite is reviewed briefly. Information relative to past production and reserves of bauxite in Arkansas also is given. A resume of the development of the industry in Arkansas, the exploration and mining methods employed, the various uses to which the bauxite is put, and a brief outline of the geology of bauxite in Arkansas complete the -background.

Jan 1, 1948

By M. Handley

The Witwatersrand Basin contains by far the most gold ever found, and has hosted mining from its discovery in 1886 to the present. For many years, South Africa was the world’s largest producerof gold, nearly all of which came from the Witwatersrand. Since 2000, South Africa has fallen back several positions because of declining gold output. There are many complex and varied reasons for this; however, declining gold resources in the Witwatersrand Basin are not one of them. As far as the author knows, there are no qualified estimates in the literature of gold remaining in the Witwatersrand Basin. This paper collects mining data from several sources and then, using elementary gold accounting and error analysis, attempts to estimate the amount of gold remaining in the Witwatersrand Basin. It includes gold underground in existing and defunct mines, in evaluated ore resources, and dumps. Compiled data from 1887 to 2019 shows that 50 200 t of gold were produced by Witwatersrand mines, while it is estimated that a further 48 100 t remainunderground, both within and outside of mine leases, a further 1 600 t on the surface in tailings,and an unknown amount in rock dumps. Nearly all of this gold will remain inaccessible with current mining methods, and major technical developments in mining will be necessary before any of the gold can be categorized as a code-compliant resource or reserve. To win this prize, the mining industry will have to rethink its approach to mining, both in old mining leases and in the unexploited ground. It will also have to find effective means of preventing gold theft and informal mining, which are on the rise.

Apr 5, 2023

By A. B. Needham

This paper, which describes mining practices at a mine in the Cave- in-Rock, Illinois, fluorspar district, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. Ore deposits in the southern Illinois-western Kentucky fluorspar dis- trict are of two general types (1) the flat-bedded, lenticular replacement and (2) the relatively narrow, rather steeply dipping fault or fissure filling. This paper describes production methods used and results obtained in mining one of the bedded lenticular ore bodies that are prevalent in the northeast portion of the district near Cave-in-Rock.

Aug 1, 1949

By Everard Leland

This paper, describing the mining practices at the Pilares mine, Pilares de Nacozari, Sonora, Mexico, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts. At present (1930) practically all the mineral production from the Nacozari district is from the Pilares mine of the Moctezuma Copper Co., a subsidiary of the Phelps Dodge Corporation. The ore is mined for its copper but contains associated silver in small quantities.

Jan 1, 1930