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By Daniel Hodouin

Artificial neural networks (ANN) are of growing interest in a wide variety of applications. Pattern recognition, speech processing, financial analysis, signal processing and process control are at present the most successful ones. This paper is an attempt to illustrate the potentiality of ANN applied to mineral processing. An introduction to the technology of ANN is first proposed to describe the various components and to explain the various phases encountered in setting up a network. Then examples are given to illustrate the use of ANN dynamic modelling of mineral processing units or plants and in process control.

Jan 1, 1991

By E. A. Stevens

It has been ascertained in recent years that certain rocktypes, geological formations and structural conditions may be used as fairly reliable guides, when prospecting in recognized mineral belts or milling districts, with a reasonable certainty of discovering "pay-ore;" and that such is considered as a practically established conclusion may be inferred from a perusal of the recent reports of the U. S. Geological Survey and the literature of the several scientific societies discussing mining, geology, and kindred subjects. Cripple Creek is no exception to this conclusion, and the

Jan 1, 1903

By D. A. Paice

A portable calibrator to check tie trip setting of dc circuit breakers within an accuracy of +5% has been developed for the Bureau of Mines. It operates from a 300 volt dc trolley wire to provide controlled current pulses of 120 milliseconds duration and continuously adjustable from 1400 to 3600 A. These current pulses enable a breaker dc trip current to be determined and subject the contacts to full current rating. The equipment is simple to use and weighs 86 pounds. Connections are made with protected, clamp-on leads which are separately connected and weigh about 22 pounds. An accurate calibration procedure takes less than 5 minutes to complete.

Jan 1, 1978

By E. G. King

Thermodynamic calculations involving the oxides of tungsten and molybdenum have been hampered by lack of accurate entropies and high temperature heat contents. This paper presents work by the Federal Bureau of Mines on new low-temperature heat-capacity data leading to the evaluation of the 298.15° K. entropies of tungsten dioxide and tungsten trioxide, as well as high-temperature heat contents (above 298.15° K.) of molybdenum dioxide, molybdenum tri-oxide, tungsten dioxide, and tungsten trioxide. Included are heats of fusion of the two trioxides. The heats of formation at 298.15° K. of these four oxides are tabulated as measured by Mah4 5/ of this laboratory. Included also are the 298.15° K. entropy of Mo02 measured by Kin 6/ of this laboratory, and that for Mo03 according to Kelley and King.7/ These basic data provide a consistent compilation from which to perform accurate thermodynamic calculations involving these compounds. No previous low-temperature- heat-capacity measurements have been reported for tungsten dioxide. Seltz, Dunkerley, and DeWitt8/ measured the low-temperature heat capacity of tungsten trioxide. The only previously-reported high-temperature heat-content measurements for any of the oxides were conducted by Cosgrove and Snyder,9/ who measured molybdenum trioxide to 1,300° K.

Jan 1, 1960

By H. Y. Sohn

The ignition and combustion of chalcopyrite particles under suspension-smelting conditions, in which the particle-particle interaction is neglected, has been analyzed by considering the intrinsic kinetics of oxidation and heat and mass transfer between the particle and its surroundings. Reasonable agreement has been obtained between the calculated results and experimental results from a laminar-flow furnace reported in the literature. This computation- al procedure has further been applied to flash-smelting conditions. Under suspension-smelting conditions (Sh = Nu = 2), chalcopyrite particles ignite at around 960 K. The effects of various parameters, such as oxygen concentration, particle size, and gas temperature, have also been evaluated. Comparison between calculated results in this work and experimental observations indicates that SO is the important gaseous product that forms at the surface of the particle.

Jan 1, 1993

By M. L. Glenn

The Bureau of Mines is conducting research on substitutes for chromium-containing alloys in order to conserve imported critical and strategic materials. Part of this research concentrates on finding low-chromium substitutes for heat-resisting stainless steels for the temperature range 600° to 800° C. Ferritic alloys are emphasized that have oxidation resistance provided by chromium contents as low as 10 pct and stress rupture strength provided by the precipitation of the chi(X)-phase intermetallic compound, (Fe36Cr12 (Mo, Ti)10). Initially, research was concentrated on selecting an alloy composition having a minimum chromium content with strengthening provided by the X-phase. An Fe-(10-12 pct)Cr-6 pct Mo-(1.5-2.0 pct)Ti alloy was selected. After the alloy selection, the tensile, stress rupture, and oxidation properties were determined. Stress rupture properties were found to be similar to those of 304 stainless steel. However, the alloys possessed brittleness during both stress rupture and tensile testing, possibly as a result of too high a content of molybdenum and titanium. Higher than expected oxidation rates were found that may be caused by the high molybdenum content.

Jan 1, 1984

By John B. Bennett

In this report estimates are presented of the impact of the passage of five recently proposed "acid rain" bills on electric utility costs for coal-burning utilities servicing the domestic aluminum smelting industry, and on the costs of production for affected aluminum smelters. As aluminum smelting is an energy-intensive industry, domestic increases in electricity prices could affect the industry's competitiveness. Energy costs in U.S. aluminum smelting are compared to aluminum smelting energy costs in the rest-of-the-world. Governmental policies affecting these energy costs are discussed.

Jan 1, 1988

By K. Ebrahimi-Nasrabadi

The dependence between the extent of conversion of cryptocrystalline magnesite to caustic magnesia was studied experimentally in the temperature range of 400?1200 °C and for calcination times up to 8 h. A TGA?DTA analysis showed that decomposition begins at temperatures as low as 340 °C and is completed at 600 °C. Measurements of specific surface area (SSA), iodine adsorption number (IN), crystallite size, and loss on ignition were carried out to characterize the product quality. It was found that while all the parameters are dependent on the extent of calcination, densification of the product caused by grain coarsening affects their final values. As a consequence, SSA and IN went through a maximum with time. The study showed that high quality caustic calcined magnesia can be produced in a narrow range of temperature (600?650 °C) and time (1?4 h). Medium quality caustic calcined magnesia can be made within a wider range of parameters.

Aug 1, 2013

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By R. W. Mei, R. A. Strombom, D. J. Moore

"Heat-shrinkable cable accessories are solving problems in the mining industry. This paper describes a range of products used by the industry, including low-voltage splices, high-voltage splices to 8.7 k V, cable repair sleeves, mining cable terminations used on system voltages up to 25 kV and motor connection kits up to 8 k V. Technical procedures and designs are illustrated.IntroductionThe development of high-performance heat-shrinkable materials slightly over 20 years ago proved to be one of the major technological breakthroughs in power cable accessories. Heat-shrinkable products were introduced initially for use as low-volt age cable accessories in the aircraft and electronics industry. A program of continuous development and product introduction now enables the manufacturer to offer a broad range of products for mining, industrial and utility electrical systems.With the advent of atomic energy, an important discovery was made-exposure of some plastic materials to high-energy electrons can cause the permanent crosslinking, or intermolecular joining, of adjacent molecules. Once the material has been crosslinked, it will not melt or flow at any temperature.The unique properties of heat-shrinkable products also result from the exposure of special thermoplastic formulations to high-energy electrons. Because of crosslinking, these products have perfect elastic memory. The heat-shrinkable products are supplied in expanded condition. When heated, they will shrink and tightly cover the object over which they have been placed. 'The functional and operating demands of mine cable accessories exceeded the classic electronic applications of heat shrinkable materials. These demands required a very sophisticated program to develop materials and adhesive systems that could endure the operational environment associated with the mining industry,Ease of assembly, low installed cost and operational reliability are among the main reasons for the acceptance of heat-shrinkable mine cable accessories in electrically powered mines. For over a decade, these systems have been demonstrating proven performance."

Jan 1, 1980

By Elizabeth Carvalho L. Cardoso, Ademar B. Lugão, Sandra R. Scagliusi

This research investigated how gamma-radiation affected PP/HMSPP structural foams filled with biodegradable synthetic polyester PLA in terms of thermal properties, biodegradability and infrared spectrum. Polymers are used in various applications providing enormous quantities of wastes in environment and contributing with 20–30% of total volume of solid residues. Besides, shortage of plastics resins obtained from fossil base is addressing research and development toward alternative materials; environmental concerning in litter reduction is being directed to renewable polymers for manufacturing of polymeric foams. Biodegradable polymers, a new generation of polymers produced from various natural resources, environmentally safe and friendly, can contribute for pollution reduction. PLA (poly(lactic) acid)) was chosen to be blended with PP/HMSPP. Blends thereof were subjected to gamma radiation at 50, 100, 150, 200 and 500 kGydoses.Soilburialtestpointedtowardapartialbiodegradationofirradiated PLA-PP/HMSPP foams; other characterizations involved TG/DTG technique and FTIR assessments.

Mar 1, 2017

By Peter Riccio

Oxiana Sepon?s mineral processing facility in south central Laos produces copper cathode using leach-autoclave-SX/EW flotation technology. Pyrite recovery in the flotation circuit is critical to the operation, as it is used to generate acid for the leach circuit. However, low pyrite recovery has been an ongoing challenge in the flotation circuit. Tailings characterization work done by Ian Wark Research Institute showed that the pyrite losses to the tail are made up of a combination of coarse liberated particles and finer particles that have been coated by clay fines. In December of 2005, a joint Cytec-Oxiana technical program was initiated to address the pyrite recovery issue. A series of diagnostic tests were performed in the Cytec Stamford Research Facility using synthetic plant water showing that the collector was precipitating as a metal salt, and was un-available for mineral attachment. The tests also identified several collector chemistries that would likely be robust in the Sepon low pH, high dissolved metal ion environment, and will not complex with ferric, ferrous, or copper in solution. With the support of the Sepon on-site engineers, an extensive, successful laboratory program was completed, which then was followed by on plant testing that showed a step wise improvement in pyrite recovery.

Jan 1, 2014

By Alan M. Bateman

Before World War II we proudly considered that we were the nation of all the world most richly endowed in mineral resources. We knew it was no accident that those countries abundantly supplied with mineral resources became the great manufacturing nations, and the politically and militarily strong ones; and that our own great industrial cities sprang up where coal and iron met. We all reallized, especially we of the mining profession, that the energy of fuels and the solidity of metals spelled industrial growth and in turn industrial might and that other nations came to regard mineral self-sufficiency as one of the chief goalsof economic nationalism.

Jan 1, 1949

By P. F. Stratton, M Huggahalli, N Saxena

"Several studies have been carried out to determine how the optimum atmosphere conditions in the heat treatment of metals can be established for a given product by using different gas injectors and varying atmosphere flow rate and composition. The most common approach taken to gain insight into furnace atmospheres has been to use commercial computational fluid dynamics codes and examples of their use are shown. However, the complexity of these codes, the difficulty in establishing boundary conditions, their cost and computational demands limit their usability in solving day-to-day production problems.A simplified, web-based model of a furnace atmosphere is described where the conservation equations are solved to determine the composition profiles of the atmosphere in the furnace. Although the model is restricted in scope to certain types of furnace, it is shown to give better results than CFD when boundary conditions are uncertain. The application of the model to the understanding of existing furnace conditions and to determining ways of optimising the use of gases are discussed. IntroductionThe important role of protective atmospheres during heat treatment of metals, furnace brazing of assemblies and soldering of printed circuit boards is well established. The atmosphere in the furnace prevents air ingress and oxidation of the parts, helps flush away any flux or binder from braze and solder pastes and provides an important mode of heat transfer [1]. In a batch furnace having typically one or two gas injectors, the gas utilisation and process can be optimised by minimising air leaks and mantaining atmosphere homogeneity with fans or other atmosphere circulation techniques. In a continuous furnace, however, atmosphere optimisation is more difficult as furnace inlets and exits can also let in air. The atmosphere requirements of different stages of heat treatment, brazing or soldering vary [2]. Achieving these atmospheres in different sections of the open-ended furnace is a relatively complex task. Methods such as atmosphere zoning and the use of physical curtains and gas injectors have evolved with time, though it is hard to predict how effective these techniques will be for a given furnace and process. Experts in the field tend to rely on experience and rules-of-thumb rather than scientific method to achieve the required results."

Jan 1, 2001

By J. A. Holtkamp

Environmental regulation in Mexico has matured dramatically and effectively in the last decade. The gap between environmental regulation in the United States and Mexico is rapidly narrowing, so much so that it is no longer necessarily less burdensome to operate in Mexico from a regulatory perspective. This paper is intended to give a general overview of the system of environmental regulation in Mexico. The actual application of Mexican laws and regulations governing the environment to a specific operation will require a much more detailed review of the applicable environmental standards.

Jan 1, 1994

By Jamey Rosen, Georgette Hlepas

"Bluestone Dam is a concrete gravity structure with an overall length of 2,060 feet and a maximum height of 165 feet above the streambed. Several major project modification designs have been implemented and additional modifications are currently in construction and design phases. Due to the various modifications since original construction was completed in 1948, detailed documentation with visualization of the project features is needed. A three-dimensional model of the internal and external features of Bluestone Dam was generated from LiDAR data, survey information, and other data sources. One of the key features of interest in this model is an accurate visualization of over 200 dam anchors based on downhole anchor surveys. The model is accessible in Microstation and Geographic Information Systems (GIS), allowing users to rotate the anchors in three dimensions; view them in the context of geology, internal dam structural features, historical construction records, site photographs, bathymetric data, and instrumentation data. Users can “click” on individual anchors to view associated construction details and open a comprehensive installation packages. The model will be used by the United States Army Corps of Engineers (USACE) as part of a larger Geospatial Data Management System as a historical accounting of the project construction data, and be a long-term living document for use by both design engineers and operations staff to assess dam safety risk and to design future project modifications.IntroductionDuring the life of any project, critical data concerning the construction and performance history are required to be collected and maintained. The data collected prior, during, and post-project construction help with the design process, ensure that the project is built to specifications and is performing as per design intent. During the Post-Implementation Evaluation (an evaluation performed after a major project modification), these data are used to visualize the repairs, verify the construction was performed per design intent, and document the history of the construction phases, associated test results, and overall effect on the project. The project described in this paper is the construction of a system of tools to effectively use these data.Data collected and maintained during the operations phase helps to ensure that the project is continuing to perform as per design and aids in advance warning of any potential failure or required maintenance. Dam Safety, Emergency Management (EM), and Operations and Maintenance personnel can use the system to verify the status of the project in preparation for a high flood event. For example, if there is repair work being performed on a critical feature of the project that would affect the operation of the dam structure during a flood event, Operations personnel would be responsible to update the status of the system such that Dam Safety and EM would be able to identify the feature that is out of service, its date of expected repair completion, and the implications during a flood. In addition, risk assessments typically require a full history of the project and its performance. Any concerns that arise concerning the safety or performance of a project will require a full documented history of the project and its components. Proper documentation and data management are key in this assessment process."

Jan 1, 2016

By M. W. Grabinsky, P. B. Tomory, J. Carvalho, J. H. Curran

Many underground mining operations use Split Set friction stabilizer bolts for rock support. Currently, however, little has been done to quantify the effects of various rock mechanics and operational parameters on the capacity of frictional support systems. The strength of Split Sets is usually measured by means of a pull test wherein a jacking force is applied to the bolt and a slip load is obtained. In order to evolve a rational design procedure for this type of support, an extensive database of over 900 pull test results from more than 50 mines through- out North America has been assembled and analyzed. Associated relevant rock mechanics parameters (rock type and quality) and operational details (drilling method, bit size, drive time, time to pull test) were also obtained, as completely as possible, for each test. Analysis of the information has yielded several charts that relate pull-out strength to relevant parameters and simple statistical analyses were conducted where necessary. Quantified distributions for pull-out strength were also produced for several operating conditions. The factors that most significantly affect bolt strength have been identified and specific applications to design are discussed. The information presented will assist mining engineers in designing safer and more economic support using Split Sets.

Jan 1, 1998

By Tania Schmid, Marco Portal Valdivia, Sandra Nowosad

Today’s mining industry faces rapid transformation driven by automation, climate responsibility, and ESG demands, requiring more than technical expertise. Future mining engineers must blend engineering excellence with key human skills such as communication, leadership, resilience, empathy, adaptation to change, curiosity and lifelong learning. Based on two recent surveys, one to senior leaders with over ten years of experience in the mining industry and a second, focused on understanding the perceptions of young professionals, this paper explores which skills become core competencies by 2030 for navigating complexity, leading responsibly, and enabling sustainable transformation. Furthermore, it also examines how educational institutions can adopt strategies to foster the development of these critical skills, preparing future mining talent for evolving challenges.

Feb 22, 2026

The following methods should be used to protect miners from the adverse health effects of exposure to respirable coal mine dust and respirable crystalline silica: ? Informing workers about hazards ? Establishing written emergency procedures ? Using engineering controls, work practices, and personal protective equipment (including respiratory protection when dust control equipment is being installed, maintained, or repaired) ? Monitoring exposures ? Conducting medical screening and surveillance ? Encouraging smoking cessation ? Maintaining medical records

Jan 1, 1997