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In many base metal sulphide concentrators reagents such as collector and cyanide are often added to the grinding mill as well as to the flotation circuit. Whilst good reasons can be cited for splitting the reagent addition in this way, the benefits of such are rarely quantified and the complex reagent-mineral-media interactions occurring during milling are often poorly understood in terms of pulp chemistry. A new laboratory batch grinding mill designed by Magotteaux allows the user to measure, monitor, and control the pulp chemical conditions during grinding when testing different ores and media. Some of these parameters include pulp pH, pulp Eh, temperature, gaseous atmosphere, and dissolved oxygen concentration. In a recent development, the mill has been coupled with a simple on-line reagent monitoring system, designed by CSIRO, which allows the levels of species such as xanthate and cyanide in the grinding pulp to also be measured continuously during milling using a robust UV detection system. In this way the uptake of collector during grinding and the rate and ex-tent of cyanide interaction with the minerals and media can be determined as a function of grinding time. A series of grinding tests using an Australian nickel sulphide ore was conducted with the coupled system in which the cyanide dose, xanthate dose, and media type were systematically varied. The xanthate and cyanide levels were monitored as a function of grinding time and the data collected are discussed in terms of the pulp chemistry of the system and implications for plant reagent dosing strategies.

Jan 1, 2014

By R. E. Somers

Discussion of the paper of R. E. SOMERS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 101, May, 1915, pp. 957 to 996. A. C. LAWSON, Berkeley, Cal.-One point to which Mr. Graton (in summarizing the paper for us) called attention is that the author had not explained why some copper was fixed in the zone of oxidation. I recollect very well puzzling over that question at Ely, Nev., some years ago. Mr. Sales, in his paper on Butte,1 suggests the explanation. It is clue according to him to the paucity of pyrite in the primary ore. Where there is abundant pyrite sufficient sulphuric acid is formed by oxidation to take all the copper into solution and carry it to lower levels; but where the pyrite is scant so that insufficient sulphuric acid is formed, some of the copper is carbonated and so fixed in the gossan. The hypothesis, or some modification of it, as for example the combination of the sulphuric acid with lime, would appear to explain satisfactorily the fixation of the copper in the gossan as carbonate. I have, however, had no occasion in recent years to study the phenomenon. L. C. GRATON, Cambridge, Mass.-As I remember, the rocks in which the chrysocolla occurs in the Burro Mountains are both silicified and kaolinized. It seems probable that in surroundings deficient in carbon dioxide, complete oxidation of chalcocite may yield chrysocolla up to a maximum of half the copper in the chalcocite; while in rocks, like garnet contact zones and certain easily decomposable porphyries, surface decomposition appears often to yield silica in the necessary form to convert the copper of primary sulphides into chrysocolla immediately and directly upon oxidation.

Jan 12, 1915

A preliminary research and development program dated April 25, 1974, was prepared for Development Engineering, Inc. (DEI) for laboratory, field and other engineering studies on the disposal of retorted oil shale. This program was revised and published as a final document dated December 17, 1974. The document included discussions on the peculiarities of retorted shale materials to be investigated and discussions of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The proposed research and development program was divided into eight work phases as follows: I Program Development. II Exploratory Laboratory Tests on Old U.S.B.M. Retorted Shale. III Laboratory Tests on Pilot Plant Retorted Shales. IV Laboratory Tests on Retorted Shales from the Semi-Works Plant.

Jan 1, 1976

By Thomas M. Barczak

This U.S. Bureau of Mines report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. The involvement and contributions made by the Bureau during these developments are also discussed. Two major periods of history are analyzed: (1) from 1875 to 1950 when small advancing faces were operated manually, and (2) from 1950 to 1990 when mechanized extraction and powered roof supports provided a system to efficiently extract large coal panels. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) powered roof supports, (3) high-capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of longwall utilization, face production, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By T. I. Weston

This is one of a series of papers being prepared for and published by the United States Bureau of Mines, describing mining and milling methods and costs at crushed-stone plants throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total production costs. It is recognized' tat publication of total production costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. However, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no mis-understanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance-of F. W. Horton, mining engineer, United States Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

By Anthony Harding

In a world of technology and electronic communication, it is easy to forget what engineers do best with a problem: sitting around a table, exchanging views and ideas with sketches and respecting everyone?s view. This was the approach adopted in the project to arrive at a solution for the cross passage opening sup-port for the Seattle University Link Extension. Schedule and space constraints usually impede concurrent cross passage excavation and tunnel boring machine (TBM) operation. And where the space is constrained, opening support solutions that maximize available cross sections are of great benefit. While there are a number of solutions that minimize space, some of these solutions can require expensive steelwork and extensive drilling and fixing. However, following a detailed round-the-table discussion of the options and constraints, it was identified that a shotcrete shell would not only limit obstruction of the space during installation, but also permit easy installation, particularly around services, and avoid costly steelwork and drilling and fixing.

By S. C. Schaefer

The Bureau of Mines investigated tIle standard Gibbs energies of formation, 8Gfo, for MllF2 (manganese difluoride) and CoF2 (cobalt difluo-ride). High-temperature galvanic cells employing CaF2 (calcium diflu-oride) as the solid electrolyte were used to measure the open-circuit potentials for the cell reactions ?

Jan 1, 1985

By Ron Light, Doug Applett

"HistoryThe Nanisivik mine began operation in October 1976 as the world's most northerly metal mine and the first permanent industrial project in the Canadian High Arctic. Located 700 km north of the Arctic Circle on Baffin Island's Strathcona Sound, exploration by Texasgulf Inc. between 1957 and 1970 had outlined the ore deposit. In 1974, Nanisivik Mines Ltd. was formed with Mineral Resources International, the Government of Canada, Metallgesellschaft and Billiton being shareholders, and Strathcona Mineral Services Ltd. providing project management. In 1996, Breakwater Resources purchased the mine from Alberta Energy Corporation Limited which had recently acquired the assets of then owners Conwest Exploration Ltd.Ore DepositThe main ore deposit is very flat, approximately 80 m in width and varying in thickness from 3 m to 16 m. The length of the deposit is approximately 3000 m with satellite zones located on the perimeter of the main zone. The economic mineralization is sphalerite with minor galena and silver. The sphalerite and galena are coarse grained and associated with pyrite as the main gangue component with minor inclusions pf dolomite and calcite within the deposit. The deposit being hosted in a permafi·ost environment creates a number of challenges. Dry drilling is employed in room and pillar production drilling. The permafrost aids in the stability of both the pillars and the back."

Jan 1, 2000

By Hanns J. Billmayer

This report, which covers the period from June 15, 1974 to May 30, 1975, describes the work performed in compliance with the requirements of Contract No. H0242065 and modifications 1, 2, and 3 thereto. The purpose of the original contract was to equip the second shuttle car in the Jewell Ridge No. 12 mine, section 6R, with a refined design canopy and seats. In addition, several refinements and improvements were to be designed and installed at the same location on the cutter and the loader. However, during October 1974 in response to a request from the Technical Project Officer, the contract was modified to eliminate all of the cutter and loader tasks and substitute the design, fabrication, and installation of an improved canopy on the no. 2 roof drill in the above mentioned section of the Jewell Ridge No. 12 mine.

Jan 1, 1975

By George Carlos dos Santos Anselmo

O efeito de memória de forma tem como principal objetivo a recuperação da forma por meio de aquecimento acima das temperaturas críticas de transformação. Fitas das ligas Ti50Ni46Cu4 e Ti50Ni44Cu6 (% at) foram preparadas através do processo melt spinnig com velocidade da roda de 38 m/s e 50 m/s. A caracterização das fitas foi feita por Calorimetria Diferencial de Varredura (DSC) e Microscopia Eletrônica de Varredura (MEV). Foi observado que com o aumento da velocidade de rotação da roda de 38 para 50 m/s um refino de grão foi observado e as temperaturas de transformação diminuíram chegando à variação de aproximadamente 7°C. A solidificação rápida produz defeitos na estrutura da liga e, consequentemente, uma maior dificuldade de ocorrer as transformações de fase, bem como produz um refino de grão.

Aug 16, 2017

By W. Miles

Introduction From a historical perspective, bentonite is the common rock term for various uses and applications. Its name originates from water-based muds near Fort Benton used for lubrication of wagon wheels during the 19th century migration to western territories (which are presently part of the United States) when the pioneers ran out of axle grease. From a clay mineralogy perspective, bentonite is composed primarily of montmorillonite, an expandable magnesium aluminum silicate clay mineral. When magnesium occupies an octahedral structural site that usually contains an aluminum atom, a negative charge is created. In order to neutralize negative charges, cations are drawn to the interlayer surfaces between clay mineral sheet structures. Modern applications for bentonite depend on the sodium or calcium cation populations and other characteristics of the clay mineral. When sodium is the dominant cation, the material is also called sodium bentonite, also known as swelling bentonite, western bentonite or Wyoming bentonite. When calcium or magnesium is the dominant cation, the material is called calcium bentonite, also known as nonswelling bentonite or southern bentonite. Swelling bentonite is recognized for its rapid hydration of interlayer sodium and subsequent dramatic expansion up to more than 20 times its original volume. Low shear can then disperse the hydrated sodium bentonite to form suspensions that increase viscosity and suspend solids. However, when shear is subsequently eliminated a sodium bentonite slurry gels. Characteristically, nonswelling calcium bentonite has relatively poor hydration properties and thus low expansion of the clay mineral. When subjected to low shear, calcium bentonite exhibits very little viscosity and poor suspension. Additionally, when shear is subsequently eliminated no more than minimal gelling takes place. The domestic and export markets related to both swelling and nonswelling bentonite are discussed below.

Jan 1, 2007

By Jonathan Baggett, Nino Ripepi, Amin Abbasi, Richard Bishop, Juan Monsalve, John Hole

This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karst voids are complex and challenging ground-control risks. Traditional methods of predicting karst void locations, such as probe drilling, are impeded by the inconsistent spatial distribution and variable sizes of the features as reported by Li et al. (J Rock Mechan Geotech Eng:232–242, 2010) and Hassan et al. (Procedia Chem 19:737–742, 2016). Ground-penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in conductivity and dielectric permittivity between limestone and open karst cavities causes strong reflections. GPR is frequently used as a geophysical surveying technique in several industries; however, there is a lack of published research on underground mining GPR applications as reported by Zhao et al. (2015a; Geophys J Int:62–71, 2015b) and Eskelinen and Pellinen (Constr Build Mater:888–898, 2018). The purpose of this work is to demonstrate the use of GPR in an underground stone mine and to discuss the importance of karst void detection ahead of mining.

By R. D. Haynes

Coal, gas, and oil in many geological formations of the Eastern United States are intimately associated but have traditionally been recovered independently of each other. Oil and gas wells, however, are often spaced sufficiently close to cause the subsequent loss of up to 50 percent of the recoverable coal in the form of pillars or barriers left for mine safety purposes. A long-range planning technique was devised for exploiting oil and gas wells simultaneously with the mining of coal to recover the maximum fuel potential of the formations. Planned plugging of oil and gas wells, determined partly from production predictions via decline curve analysis, is coordinated with a mine development plan to achieve maximum coal recovery and reduce overall production losses of gas and oil due to plugging of the wells.

Jan 1, 1973

By Ruari Soutar-Dawson, Fisher Wang, Alan Boylston, Michael Denzel

Vertical stirred mills are increasingly used for fine grinding applications in the mineral processing industry due to their high energy efficiency. Thus, modeling power draw is of great interest proven by the effort in previous work including analytical models. In this contribution the development of a DEM-CFD coupled model is presented to determine power draw under different operating conditions. These include grinding media filling level, shaft speed and fluidization as well as changes in grinding compartment configuration. An extensive test program on an especially equipped test mill is initiated to validate the model.

Feb 22, 2026

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872 R W RAYMOND 1873 R W RAYMOND 1874 A L HOLLEN 1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 ECKLEY B COXE 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882

Jan 1, 1910

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872 R W RAYMOND 1873 R W RAYMOND 1874 A L HOLLEN 1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 ECKLEY B COXE 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882

Jan 1, 1910

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872 R W RAYMOND 1873 R W RAYMOND 1874 A L HOLLEN 1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 ECKLEY B COXE 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882

Jan 1, 1910

By Robert S. Archer, L. W. Kempf

It is now well known that the structure of aluminum-silicon alloys can be refined in a rather remarkable manner, with consequent improvement of physical properties, by certain treatments applied to the molten metal shortly before casting. The differences between the treated and the untreated alloys are so marked that special terms are used to distinguish them, the untreated alloys being referred to as "normal" and the treated alloys as "modified." The first practical method of accomplishing this result was that of A. Pacz,1 which consists in treating the molten metal with a salt flux of which the active ingredient is sodium fluoride. The result can also be brought about, and in a more economical manner, by the addition of small quantities of metallic sodium (or potassium) to the molten alloy shortly before casting.2 The action of the Pacz flux evidently consists essentially in the production of free sodium by the reaction of sodium fluoride with aluminum. The changing of a normal alloy to a modified alloy is referred to as "modification" and any process for accomplishing this result is a "modifying" process. Modified aluminum-silicon alloys were introduced several years ago, and it has been demonstrated both in the laboratory and in commercial practice that it is no simple matter to produce castings having the maximum or nearly the maximum properties which under favorable circumstances can be obtained. The alloys are rather sensitive to small changes in chemical composition, and the modifying process must be carried out in a very particular manner to obtain the best results. Extensive experimental work has been carried out in the laboratories of the Aluminum Co. of America with the object of determining the conditions that must be observed to make these alloys of the greatest possible value. It was necessary to learn how to control the modifying process

Jan 1, 1926

By John W. Kopp

A major concern with blasting at surface mines is generation of ground vibrations and airblast and their effects on nearby residences. This Bureau of Mines report looks at the use of millisecond delays in blast design and their effect on the resulting ground vibrations and airblast. A total of 52 production blasts were instrumented and monitored at a surface coal mine in southern Indiana. Arrays of seismographs were used to gather time histories of vibrations and airblast. The data were analyzed for peak values of vibration and airblast and for frequency con-tent. Various delay intervals were used within and between rows of blastholes. Delay intervals within rows were 17 and 42 ms, and those between rows ranged from 30 to 100 msj these intervals are equivalent to 0.5 and 1.3 ms/ft within rows and 1.2 to 4.3 ms/ft between rows. Sub-sonic delay intervals within rows reduced airblast by 6 dB. Large delay intervals between rows reduced the amplitude of ground vibrations; their frequency depended primarily upon the geology of the mine site.

Jan 1, 1986

By J. Phillip Mackey

The Peter Hayes Symposium on Pyrometallurgy, held as part of Extraction 2018, is an acknowledgement of his contributions to the basic science and principles underpinning modern pyrometallurgical processing. After completing his PhD at Strathclyde University, Scotland, in 1974, Peter took up a teaching position at The University of Queensland, Brisbane, Queensland, Australia in 1976. Peter Hayes’ research at the University since then has been focussed on: • The mechanisms and kinetics of heterogeneous solid/solid, gas/solid and liquid/ solid reactions, and • Experimental measurement of phase equilibria in complex high temperature metallurgical systems. This paper provides a brief biography of Dr. Peter Hayes and gives a full listing of Peter Hayes’ publications.