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By Alfred Opengart

During any rush hour, tens of thousands of automobiles clog the main highways leading into or out of our large cities. Inevitably one or more cars stall or plow into another, causing a momentous traffic jam. Traffic backs up for miles as drivers try to maneuver around the roadblock. As commuters, we grin and bear the inconvenience, rationalizing the delay as part of the price one pays to live in a modern society. The truth of the matter is that the engineers planning the roads have the know-how to build adequate bypass alternatives into their design. The problem is one of economics -- can the cost of eliminating roadblocks be justified? Engineers designing solutions to complex materials handling problems for modem distribution centers are just now beginning to ask this question in relation to their work. Unfortunately in many instances, it has taken an expensive "traffic jam" to bring this question to the front. In these cases, a seemingly practical system promising an attractive return on investment -- using the latest equipment and computer controls -- was designed and installed. Everything went according to plan until one day a breakdown occurred. .Product flow stopped, and management realized it was at the mercy of the "machine." In such situations, management had assumed it could minimize the risks of the breakdown by injecting extra manpower to operate the system manually and pay the associated costs. What it had not recognized is that manual intervention is nearly impossible with sophisticated systems. Thus, too often -- and sometimes too late -- management found itself footing a very high bill for losses incurred because of major production stoppages and missed customer shipments.

Jan 1, 1973

By Syd Peng

"As the International Conference on Ground Control in Mining (ICGCM) enters its 35th year in 2015, it is time to look back and identify the areas that need to be emphasized and to look forward to see what areas need to be researched in the future. In the past three decades, ground control has made a tremendous advancement, and many case studies published in the 36 volumes of proceedings have demonstrated its important role in the daily mining operations. However, there is still plenty of room for improvements. This paper discusses the research needs in 12 subject areas, including mine geology, rock property, zones of disturbance in overburden, computer modeling, underground stress measurements, research method, roof bolting, coal pillars, failures, subsidence, shield supports, and coal bumps.INTRODUCTIONThe International Conference on Ground Control in Mining (ICGCM) was founded in 1981. Since then, 1,546 papers have been published in the 36 conference proceedings, including the three surface subsidence workshops held in the 1981, 1986, and 1992. All types of topical areas regarding mining, from geotechnical core loggings in the exploration phase through backfilling after mining to finally spoil piles stability on the surface, have been addressed. A review of these papers, and other related literature as well, indicate that ground control has developed to become an inseparable part of mine design and a problem-solving tool for safe production.After 34 years, it is time to look back and identify the areas that need to be emphasized and to look forward to see what areas need to be researched in the future. There is no doubt that the conference series has achieved the goal for which it was originally designed: to provide an annual forum for the exchange of information among the researchers, government regulators, equipment manufacturers, consultants, service providers, and—above all—mine operators. There have been many papers addressing the application of ground control techniques for successful mine design and safe production, and, without these papers, many projects would have failed. In fact, the conference emphasis on application types of papers may have steered too far toward the application side. A review of the conference papers shows that papers have been leaning mostly toward the applied side, leaving most, if not all, fundamental issues behind in nearly every topical area. This paper addresses research needs in 12 topical areas: mine geology, rock property, zones of disturbance in overburden, computer modeling, underground stress measurements, research method, roof bolting, coal pillars, failures, subsidence, shield supports, and coal bumps."

Jan 1, 2015

Discussions of the papers with a written contribution on Paper No. 11 and authors' written replies. Also brief obituary of Dr. T. David Jones on p146.

Jan 1, 1947

By Bishop D. J

The Imperial Smelting Process for the simultaneous production of zinc and lead is probably regarded by the ecologist as a necessary evil with the benefits of its products marginally outweighing the adverse effects of its operation. The purpose of the paper is to examine the environmental impact of the process and to provide information which will demonstrate that the process has considerable indirect environmental benefits and that success is being achieved in reducing direct pollution of the environment by the process. About 12 per cent of the world's zinc and seven per cent of its lead is produced by the process. This proportion will increase with the construction of a new smelter in China. After a brief description of the process the paper considers one of its principal advantages, its ability to treat bulk concentrates. The production of these at the mine can have a number of environmental benefits. Less comminution may be required to separate the metals from the gangue than is needed to separate them from each other; recoveries can be improved in flotation resulting in cleaner tailings dams, less power demand and reduced consumption of potentially hazardous reagents. Simplification of mining and above ground ore handling may also give significant benefits . The process is a considerable consumer of secondary materials such as galvanisers' ashes, copper smelter dusts and materials containing zinc and lead derived from steel plant dusts. The majority of these materials are fed to the blast furnace after hot briquetting. The consumption of secondary materials is a considerable environmental benefit since otherwise they would require to be dumped in secure land-fill sites. The operation of the process itself continues to be subjected to increasingly stringent environmental standards of which examples are provided. Details are provided of lead emissions at Avonmouth showing considerable success in reducing these while increasing production. The slag from the process continues to find many useful applications.

Jan 1, 1993

By A. Ducastel, S. Connemann, A. Stark, F. Bouillot, C. Fricke-Begemann, LSA, H. Knapp, L. Horckmans

"Refractory materials are essential for all high-temperature applications in industry. Depending on the position in the furnace and specific process requirements, refractories are produced from several raw materials, such as dolomite, magnesite, bauxite, graphite or chromite. Most of these raw materials are not rare but strict quality requirements limit the producers of refractories to only a few deposits in the world. Thus, raw material supply is a critical factor for the production of refractories and accounts for 40-50 % of the total costs of refractories.A possible way to lower dependency on raw material supply is recycling of spent refractories. Main challenge in recycling is the separation of different brick types from each other and the removal of impurities, such as steel or slag. The European FP7 project REFRASORT aims to apply sensor-based sorting for separation of spent refractories. Sensor-based sorting is known from food industry, recycling and mineral processing and has proven its reliability. Nevertheless, some adjustments are necessary compared to applications in mineral processing because of other sensor-types and a higher number of products in one sorting step. This paper presents the results of feasibility tests for sensor-based sorting of refractories with near infrared spectroscopy and laser-induced breakdown spectroscopy (LIBS). Both sensors showed the potential to identify different brick types but the most promising results were obtained using LIBS technology. INTRODUCTIONRefractories are solid, ceramic products, which can sustain temperatures of more than 1500°C, without losing their stability or shape. Bricks of refractories have to withstand corrosion in contact with liquid steel or slag. Various high temperature applications, such as the production of glass, steel, copper or cement, require high quality refractories. The quality requirements of refractory bricks are strict, because small impurities can lower the thermal strength significantly."

Jan 1, 2016

By E. V. Konopleva, H. J. McQueen

Steels in high variety have been providing strength and ductility for more than a century mainly through complex heat treatments following hot shaping. The economical and sustainable goal was a steel with the two operations combined through applying knowledge of dislocations and strengthening mechanisms aided by new mechanical and microstructural techniques. Primary hot reversing-mill rolling produced static recrystallization (SRX) between every pass to significantly finer grain size. Hot torsion showed that with lay-on temperature and rate of reduction suited to gradual precipitation of minor additions of Nb, the austenite grains would become highly pancaked; the existence of very fine subgrains along the grain boundaries (GB) could be deduced from tests on stainless austenite. The HSLA strip had to be water-jet cooled immediately to prevent SRX at austenite GB and ensuring complete transformation to ferrite avoiding grain growth after coiling. Confirmation on old mills and successful product led to the design of more flexible mills for wider range of compositions and products. A significant one was auto bumpers that reduced crash damage. More crack-resisting compositions were developed for strip welding into line pipe for arctic oil transport. Lower metal consumption and easier fabrication has resulted in more sustainable welded bridging.

Jan 1, 2015

By R. T. Richins

Coeur d'Alene Mines Corporation (CDE) is a precious metals mining company. The company's three mining operations are located In Nevada and Idaho. Collectively, these mines (Rochester in Nevada, and the Galena and Coeur In Idaho) produced about 61,000 ounces of gold and more than 7.5 million ounces of silver in 1991. The company is currently planning the development of two major properties; the Fachinal gold-silver project in Chile and the Kensington gold project near Juneau, Alaska. Fachinal and Kensington hold encouraging potential to significantly expand CDE's gold production during this decade. The permitting process for these two distinctly contrasting environmental settings, project design requirements and regulatory/political circumstances provide the basis for a comparative analysis of licensing and permitting requirements, timeliness of the permitting process and costs in the U.S. and Chile.

Jan 1, 1993

By A. Trusiak

"Increasing energy costs in mineral processing is making it necessary for tighter controls over various parts of the concentrating process. Continuous monitoring and control of critical process streams can be easily performed by today's many computer systems. Indeed, the list of successful applications of computers to grinding and flotation control continues to grow. The day is rapidly approaching when the use of computers within concentrators for either process control or simply metallurgical accounting will no longer be a luxury, but a necessity. The benefits from such applications far out weight the initial investment.This paper describes the current application of a process control system at Brunswick Mining in north-eastern New Brunswick. Emphasis is placed on the control of a CuPb flotation circuit, and the benefits derived-from this control.No. 12 Cu-Pb Flotation: The complex nature of the Brunswick flotation process has been described else-where. 1,2,3 Four final concentrates are eventually produced, these being a Zn concentrate assaying 53% Zn, a 30% Pb concentrate, a 20% Cu concentrate, and a bulk Pb Zn concentrate assaying 35% Zn and 17% Pb. The Cu concentate, Pb concentrate, and bulk Pb Zn concentrate are all derived from a primary CuPb concentrate assaying 26% Pb, 11% Zn and 1.8% Cu.The No. 12 CuPb circuit produces approximately two thirds of the total primary CuPb concentrate. No. 12 ore, assaying 3.5% Pb, 9% Zn, 0.25% Cu and 100 g/tne silver, is ground in two parallel grinding circuits. Each line uses a 3.2 x 4.2 meter rod mill in closed circuit with two parallel 3.2 x 3.9 meter ball mills. Ball mill and rod mill discharges are classified in two stages of cycloning. The secondary cyclone overflow, or flotation feed, is controlled at 65% passing 37 microns."

Jan 1, 1981

By A. M. Evans, J. H. Soulé

"INTRODUCTION Deposits of iron ore in Cherokee County, Tex., have been worked at various times in the pact, and the ore has been smelted in small local blast furnaces.Recently it was proposed to establish a charcoal blast furnace with a wood distillation plant to produce charcoal for fuel and byproducts. Financial assistance from the Reconstruction Finance Corporation was sought by George Easley and associates to enable them to purchase, move, and erect the furnace and build the required accessory plants. The furnace was to be moved from Pembroke, Fla.In August 1941, the Bureau of Mines was asked by the Office of Production Management to check the development work of Easley and associates and to ascertain (1) the iron-ore reserves, (2) the cost of mining ore and delivering it to the blast furnace, and (3) the grade and character of the ore. The Bureau of Mines was advised, while the investigation was in progress, that approximately 1,000,000 long tons of measured reserves would be sufficient to demonstrate the feasibility of operating the properties.Although deposits of iron ore are widely distributed in Cherokee County, only the Pryor Mountain, Banks and Cherokee, J. P. Acker, and Citizens State Bank tracts were sampled thoroughly by the Bureau of Mines. The iron-ore rights on these are owned by the New Birmingham Development Co., the Cherokee Development Co., or by individuals. Options to lease the ore rights were obtained by Easley, who obtained options on the Hawes Peach Orchard and Bradford tracts, also, which were examined only cursorily by the Bureau."

Aug 1, 1947

By Yuezhen Zhou, Zewei Liu, Dachun Liu, Chongfang Yang, Wenlong Jiang, Fansong Liu

A novel process that the combination of vacuum decomposition and acid leaching was proposed. The influence of distillation times, diameter and thickness of the feeding material on the mass fraction of Molybdenum (Mo) and sulphur (S) in residual was investigated. The influence of leaching temperature, leaching time, concentration of hydrochloric acid solution, and ratio of liquid to solid on leaching rates of Mo and S in acid leaching process was also investigated. Due to the fact that SO2 emission happening in the long process of traditional molybdenum metallurgy could be avoided in this novel method, this combination process was environmentally-friendly. Molybdenum powder was obtained through handling molybdenite concentrate under the optimal condition parameters, and the mass fraction of Mo reached 98.29 wt%. So it's feasible to produce molybdenum powder from molybdenite concentrate by using this new method.

Mar 1, 2017

By Giulio Rodrigues Altoé

Fibras de fique (Furcraea Andina) estão entre as lignocelulósicas naturais com grande potencial para utilização em compósitos poliméricos. O presente trabalho avalia a resistência ao impacto deste tipo de compósito com matriz epoxídica reforçada com diferentes percentuais de fibras de fique. As fibras foram embutidas sob pressão em mistura com resina epóxi DGEBA/TETA curada à temperatura ambiente por 24 horas. Os corpos de prova normalizados foram confeccionados com percentuais de até 30% em volume de fibras de fique alinhadas ao longo de todo o comprimento, estes corpos de prova foram então ensaiados em pêndulo de impacto Charpy e as superfícies de fratura analisadas por microscopia eletrônica de varredura, MEV. A resistência ao impacto aumentou substancialmente com a quantidade relativa de fibra de fique reforçando o compósito. Este desempenho foi associado à dificuldade de ruptura imposta pelas fibras bem como ao tipo de trincas resultantes da interação fibra de fique/matriz epoxídica que ajuda a absorver a energia do impacto.

Aug 17, 2017

By Thornton L. Neathery

The low-grade talc deposits in Tallapoosa County, Alabama, are associated with a mafic-ultramafic rock complex that is part of a widely distributed schist and gneiss group. These rocks form a synform structure overlying Inner Piedmont lithology. Paragenetic sequence of the Tallapoosa talc is interpreted as enstatite-anthophyllitetalc. Talc occurs as massive boulders formed by the alteration of enstatite-anthophyllite and as finely disseminated discrete particles in the enclosing saprolite matrix. Weathered rock reaches depths as great as 60 feet. The quality and quantity of the talc, however, are variable. Mineral analyses of the talc-bearing samples, by petrographic grain count, indicate a talc content of 16 to 26 percent. Most of the talc occurs as plates or scales that are moderately stained with limonite. Fibrous talc also occurs in the deposits and is often mistaken for anthophyllite asbestos which is intimately associated with the talc. The size, shape, and occurrence of the talc deposits precludes any method of min¬ing other than open-cut. A small-scale mining operation began in the district in 1969. Potential capacity of the operation is 5, 000 tons per year. Inferred reserves, based on field investigations, are placed at approximately 8 million tons. Approved for publication by the State Geologist, Geological Survey of Alabama.

Jan 1, 1970

By A. W. Hull

The new valves described in this article are the latest product of the Research Laboratories of the General Electric Co. Some of them are still in the laboratory stage, others have already found important applications. Some of the larger ones, which have graduated from the laboratory, are waiting for their apprenticeship in industry, there to refine their frailties and complete their preparation as electrical servants. The career that awaits them, though dimly foreseen, appears fascinating. And as surely as history repeats itself, scenes still more romantic, now beyond the horizon, will unfold as we approach them. This is the romance of science. Counting Electrons Let the smallest tube lead the march of review. It is a special Pliotron, designed to measure currents smaller than any yet detected. It goes by the unromantic name of Pliotron FP-54. Fig. 1 shows this miniature tube—miniature in performance rather than size, for it is the size of an ordinary radio receiving tube. Its appearance has nothing distinctive, except the quartz beads above and below the plate, which support the grid. They minimize insulation leakage. In principle, the FP-54 is like any grid-controlled high-vacuum electron tube; but in structure and operating characteristics it is entirely special. An extra "space-charge" grid, maintained at 3 volts positive with respect to the filament, holds back the small but pernicious current of positive ions emitted by the filament; the normal plate voltage is 6 volts, grid bias 3 volts, thoriated-tungsten filament temperature 1700" K., plate current 40 microamperes. These conditions are essential to the avoidance of grid-currents, which may consist not only of insulation leakage and positive ions from the hot filament and from residual gases, but of high-speed electrons from the filament, photo emission from the grid due to the light of the filament, and electron emission caused by X-rays generated by the impact of electrons on the plate.

Jan 1, 1932

By L. Gonzalez-Sardi, W. McCombe, M. Pearson

Pressure oxidation is increasingly being used for processing refractory sulphide ores and concentrates because it offers highly effective base metal and precious metal extraction while minimizing elemental sulphur, arsenic & mercury emissions. Yet pressure oxidation processes introduce new safety concerns and process risks as demonstrated by a number of safety incidents over the last 20 years, including overfilling, oxygen-metal fires, nozzle/sparger failures, and uncontrolled pressure relief events. Chemical Process Safety regulations in the United States and Canada mandate that companies constructing or operating chemical process facilities perform a rigorous hazard and risk analysis based on either ANSI/ISA-84.00.01 or IEC 61511 safety standards to determine the level of protection required for each hazard in the plant. This paper describes the application and implementation of three (3) unique safety instrumented systems developed by Hatch for ensuring the safe operation of three different pressure oxidation processes.

Jan 1, 2014

By John B. Porter

Within the last year or so, a great deal has been heard about Southern iron ; even the Eastern markets have felt the effect of the cheap Alabama ores and coals, and public attention has again been drawn to what is now getting to be an old story—the great mineral wealth of the South. The following paper is based on a report prepared several years ago for a special purpose; but since then, through association with Mr. C. B. Going in a large analytical practice and as chemists to the Queen and Crescent Railway, I have had opportunity to increase my material so greatly that the present paper is really a completely different work. I am under very great obligation to Mr. Going, without whose assistance my work would have been very incomplete, and have also been materially assisted by Mr. F. P. Dewey, of Washington, and a host of gentlemen connected with the railroads and furnaces of the South. The arrangement of this paper is not all that could be desired. Some localities of importance are very poorly represented, both in the description and the tables of analyses. This, however, was in most instances unavoidable, as the study has been done ill the intervals of professional work. I have visited almost all the localities described, and, in all cases possible, have taken my own samples, and have made careful per-

Jan 1, 1887

By N. Nehoroshev, P. Solozhenkin, N. Voyloshnikova, A. Pshennikov

"Molecular modeling of clusters of major bismuth minerals, Bi2S3, was carried out whereby molecular models of minerals and reagents clusters were created. Their HOMO and LUMO energy levels were calculated and using known modelling equations, the absolute hardness ?, eV and electronegativity were calculated. The charges of separate atoms of clusters and the change of properties of the minerals were determined which allowed predictions of the flotation properties of raw ores containing rare bismuth minerals. Modeled complexes containing the clusters of minerals and various collectors were constructed, consisting of atoms and bonds within clusters of minerals. Major physical and chemical parameters were determined for the complexes created, including the total and electronic energy. Based on the energy calculations, predictions of the collector efficiency were proposed. The efficiency of collector was established for various thiolic reagents, the compounds of phosphorus (III) and mixtures of reagents. Theoretical results were checked and confirmed against laboratory ore flotation tests. A gold-bismuth-magnetite ore type was studied where gold, bismuth and iron (magnetite) are of industrial interest. The ore contains 2.8 g/t Au, 1.0 g/t Ag, 0.26% Bi, 45% Fe and 1.25% As. Sulphide mineralization can be mainly found in the form of pyrrhotite, pyrite and arsenopyrite. Bismuth can be mainly found in the form of bismuthite and native bismuth. Gold is fine. A flow sheet for Zhelezny Kryazh ore treatment was proposed. This flow sheet consists of grinding to 95-98% -74 µm, sulfide flotation with two cleaner with xanthate addition, cyanidation of flotation concentrate and flotation tailings included treatment with with CaO (6 kg, 6 hours), cyanidation (8 hours) and CIL (8+24 hours). Saleable products are gold doré, bismuth and iron concentrate."

Jan 1, 2014

By Chikabumi Yamauchi

The comprehensive scientific development of conventional industrial technologies stimulates the creation of new ones in the next generation. Prof. Akira Yazawa has just accomplished such an important work in the non-ferrous pyrometallurgical field. The results of his successful research are immortal. The research group of the author has conducted since 1985 fundamental studies on the application of sodium carbonate slag to copper fire refining. In the present paper, a calculation method for the distribution ratios of impurity elements between sodium carbonate slag and molten copper will be shown. The specific treatment by sodium carbonate slag will also be presented as an effective way for reducing each impurity content in the molten copper to 0.1 mass ppm, which is the level required for the production of high purity copper. The thinking-out of this evaluation method gets a hint from the Equation (2) in the text which was proposed by Prof. Akira Yazawa.

Jan 1, 2003

By Joseph M. Pugliese

The U.S. Bureau of Mines has produced a generic in situ copper mine design manual, which contains a computerized cost model for in situ copper oxide mining. The model specifies (1) site-specific parameters, which must be quantified for mine design, (2) a method for minesite design based on those parameters, and (3) a procedure for assessing economic viability for the mine design. The menu-driven computer program performs calculations for developing commercial mine design specifications, as well as capital and operating costs. The default values are based on 1986 dollars, and indices for updating costs are included. The program also provides discounted-cash-flow rate of return (DCFROR) and allows for sensitivity analyses for an in situ mining operation at any specific undisturbed copper oxide deposit. This report is to be used with the 1990 version of the computer program, which has been made user friendly. It describes the flies, tutorial, input phase, help function, and monitor display of all calculated values and of the DCFROR table. The monitor-displayed discounted initial value of investment and annual operating costs are defined. The dual rate-of-return situation and sensitivity analyses are also briefly discussed. Information is provided on obtaining the computer program on diskette.

Jan 1, 1991

By Harry Teicher

The subject of Specialty Silica Products could encompass a broad range of materials, some of which would be familiar to members of the Society of Mining Engineers. With the concurrence of your chairman, I have chosen to limit my remarks to synthetic materials, not including such siliceous materials as diatomaceous earth, asbestos, quartz and clays. For purposes of discussion, I have classified Specialty Silica Products into two groups -- powders and liquids -- which I will discuss in that order and which are categorized in Figure 1. The synthetic silica powders are amorphous to x-rays and are manufactured by various processes resulting in products of a wide range of physical and chemical properties, as well as functional performance and applications. Applications or functional properties are generally dependent upon such physical properties as micron-sized particles exhibiting large surface areas per unit weight and low apparent bulk density. Their presence in various systems modify surface properties. As summarized in Figure 2, they act as viscosity modifiers, flow conditioning agents, anti-slip agents, anti-blocking agents, flatting agents in surface coatings, reinforcing agents in polymers such as silicone rubber and numerous other applications. Although the various types of silicas exhibit various levels of functional performance in these end uses, they are not usually equally effective as direct replacements and I will briefly discuss the various types of materials.

Jan 1, 1974

By J. K. Whyatt

U.S. Bureau of Mines researchers reviewed an in situ stress estimate developed from measurements of overcore strain taken at test sites on the 7300 and 7500 levels of the Star Mine near Mullan, ID. Although the field measurements of over coring strain were found to be useful, significant deficiencies were found in the stress estimation procedure. A new stress estimate was developed incorporating statistical methods and an improved understanding of stress concentration factors for interpreting overcore strains recorded by doorstopper' cells. Spatial variability of overcore strains and the implications for stress field variability were explored.

Jan 1, 2010