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By James J. Scott

Eleven workshops were held in various locations throughout the country in an attempt to reach the many diverse groups working in various mineral commodity areas and special ties. These meetings were held between March 1, 1974 and June 25, 1975. They were held under the auspices of the Bureau of Mines Contract to the University of Missouri-Rolla which was designed to help define Bureau research and development priorities. At each workshop a summary of current Bureau research and development was presented and the attendees were asked to present their ideas on what Research and Development programs should be undertaken to meet their needs locally. Participants included representatives of federal and state agencies, educational institutions, mining companies, equipment companies and other interested parties. The workshops covered under this report include lead mining in Missouri, limestone mining, coal mining both surface and underground in the midwest and in the Rocky Mountain area, iron mining in Minnesota, two top management meetings on institutional problems and, finally, a special two-day meeting on roof control.

Jan 1, 1977

By J. B. Conway

Stress-vuptuve data for several of- the refractory metals are frequently found to yield a linear relationship between the Larson-Miller parameter and the logarithm of the applied stress. In such cases linear stress-rupture isotherms result with slopes bearing a definite relationship to the temperature. It also follows that the stress to produce rupture in a certain period of time will be linear in temperature. Data for several refractory metals have been reviewed and excellent linearity is shown in this type of isochronal plot. In addition, the af ore - mentioned lineavity leads to a linear relation between the log of the stress to produce rupture in a certain time and the homologous temperature. This has been illustrated for the Group VI-A metals, tungsten and molybdenum. EXTENSIVE use has been made of the Larson-Miller' parameter in the interpolation and extrapolation of stress-rupture and creep data. In those cases where this particular parametric approach is applicable a convenient and fairly straightforward procedure is made available for the correlation of experimental stress-rupture data. It is quite common to employ this parameter in the form of a master rupture plot in which the parameter, T(C + log tr), is expressed as a function of log stress. In many cases this functional relationship in log stress is linear within acceptable accuracy and hence the following relation results: where P is the parameter, C is the Larson-Miller constant, T is the absolute temperature, t~ is the rupture time, a is the stress, and a and b are constants. Examples of such a relationship are contained in the work of Green, Smith, and 01son2 dealing with high-temperature rupture behavior of molybdenum and in the work of Green' dealing with the high-temperature behavior of tungsten. In addition, pugh4 has shown a similar linearity for some fairly low-temperature data for molybdenum. It can be shown that when the relationship in Eq. [I] is exhibited certain generalizations can be made concerning the form of the stress-rupture isotherms. For example, rearranging yields: For a given material (constant C) at a given temperature the first term on the right-hand side of Eq. [2] is a constant and hence this equation defines a straight line when log stress is plotted as a function of log-rupture time. This is recognized as the standard form usually employed in this type of data presentation. Such linearity then suggests the linear form of the Larson-Miller parameter. Or, in other words, the linear parametric relationship in Eq. [2] results only when the stress-rupture data are linear on a log-log plot of stress vs rupture time. Another interesting observation can be made in regard to Eq. [2]. It can be noted that the slope of the stress-rupture isotherms is given by - T/b and hence a direct calculation of the constant b is available. It also follows that since the value of b is the same for all temperatures the slopes of the various isotherms on the log-log stress-rupture plot cannot be the same. Indeed, the existence of the relationship in Eq. [2] precludes a system of parallel lines on this common stress-rupture plot. As a matter of fact it further specifies that in addition to being nonparallel the slope of these isotherms must decrease (i.e., become more negative) with increasing temperature. Such a condition is indeed found to exist in the case of the stress-rupture data reported for molybdenum.' As a corollary to the above, it may be stated that stress-rupture data which do not lead to a linear log-log stress-rupture plot or whose isotherms do not exhibit a decrease in slope as the temperature increases will not yield the linear relationship of Eq. [I]. Applying Eq. [2] to two different temperatures and solving for C yields: Eq. [3] affords a simple and rapid method for calculating the Larson-Miller constant from the log-log stress-rupture plot. The slope of a given linear isotherm is measured and the value of "b" calculated based on Eq. [2] as: slope = - -Tb Then at an abscissa value of 1.0 hr (making log tr in Eq. [3] equal to zero) read the stress corresponding to rupture for two different temperatures. Substitution in [3] yields: A value of the Larson-Miller constant can thus be calculated from a few simple mathematical procedures employing data read directly from the log-log plot of the stress-rupture data. Of course, it is not to be overlooked that the above reasoning has been based on the linear relationship of Eq. [I] being applicable. However, if as mentioned above the log-log plot is

Jan 1, 1967

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.   There is a great need to improve science, natural science, education at all levels. All people must know how our planet works and that fluctuations, some inevitable, some controllable, are inevitable and that we must prepare for them. And it is clear that protecting the environment, eliminating pollution, preserving bio diversity is good economics. Ecology Economy cannot be separated.  

Jan 1, 1995

By Leandro Augusto Viana Teixeira, Angela Avelar, Ruberlan Gomes Silva, Virginia S. T. Ciminelli, Daniel Majuste

Rare earth elements are essential for modern life products and green technologies. Recent supply constraints have boosted the development of rare earth projects after the price peak of 2011. The feasibility of a project depends on the definition of a processing route, which in turn depends primarily on the rare earth mineral, with monazite and bastnaesite representing the two most relevant minerals. Monazite-type ores usually contain high acid consumption impurities, such as iron, aluminum, calcium, magnesium and phosphates, and may also contain prohibitive levels of radioactive thorium in its composition. Based on thermodynamic analysis, the present work discusses the fundamentals of a selective process route for rare earth extraction from monazite ores with high iron content. This process involves sulfation by means of concentrated sulfuric acid and roasting at a high temperature. The route yields high rare earth extraction with low iron and thorium extraction and low acid consumption. Rare earth extractions as high as 80 percent were achieved, while iron and thorium extractions were lower than 1 percent, and acid consumption was lower than 0.34 kg of sulfuric acid per kg of ore. The operational window was compared to the one predicted by thermodynamic modeling, with 700 °C representing the optimal roasting temperature.

By Ulf B. Andersson, Christina Dahnér-Lindkvist, Bruno Figueiredo, Jessa Vatcher, Jonny Sjöberg, Joel Andersson

Hydraulic fracturing to precondition the rock mass in high seismic risk environments has great potential. Unfortunately, there are many unanswered questions about how to best implement a hydraulic fracturing program at individual mine sites, and even how to best use our engineering tools to evaluate these plans. To give the hydraulic fracturing field tests at LKAB’s Kiirunavaara Mine the best chance of success, fully-coupled, discontinuum numerical modelling Itasca’s 3DEC code was used together with statistical simulations of the fracture network. For modelling purposes, it was assumed that hydraulic fracturing successfully reduces seismic risk through 1) the creation of hydraulic fractures along a plane at each injection site, and 2) activation of existing discontinuities. A variety of scenarios for the mine were evaluated, which focused on site specific uncertainties (such as the spacing of the pre-existing discontinuities) and practical solutions (such as the hydraulic fracture spacing, selection of injection medium, and hydraulic fracture site location relative to production). The discrete fracture network (DFN) realizations were developed using available statistical data for discontinuities near where hydraulic fracturing was planned.

Apr 26, 2022

By Garforth W.

The chairman announced the new government duties of the out-going President, Sir Thomas Holland, and the formation of a new standing committee on mining to advise the Advisory Council for Scientific and Industrial Research on suitable projects for grants. Some of the potential lines for investigation into the best methods of winning and presenting coal in the best commercial condition include wasteful practices in operating steam boilers, national loss due to neglecting recovery of coal by-products, and the leaving of large areas of coal for fear of spontaneous combustion or as boundary pillars and support

Dec 1, 1916

By Melinda Bissinger, Frederic Berube

Environmental considerations are important in the aerospace industry. To that effect, several elements such as engine emission, noise and materials are identified by the industry and the society as requiring significant improvements for future and current products in order to be aligned with current expectations. In this context, the industry is addressing this opportunity by investing significantly in new engineering solutions that will meet greener targets. To this effect, the impact of material choice is significant and will make a difference in the forth coming solutions. Several opportunities to develop more efficient products, quieter aircrafts using materials and manufacturing processes that will be more respectful of environmental considerations exist. The presentation will cover those elements and provide an overview of the upcoming solutions.

Jan 1, 2010

By H. Kinilakodi

The authors previously had developed a methodology that combines injury and citation measures into an overall mine safety performance evaluation tool, called the Safe Performance Index (SPI). It can be easily adopted by mine operators to monitor trends in their injury and citation experiences as a risk assessment method. In this paper, six normalized safety measures and the SPI are used to evaluate the risk that existed at mines in the two years preceding the occurrence of a fatality. The percentage of mines is given for which the risk was high or where trends of some of the safety measures indicated moderate risk. In 50% of the mines, this mine safety performance tracking method could have been helpful to the companies, state agency, or MSHA in recognizing and addressing emerging problems with actions that may have been able to prevent high-risk conditions, the fatality, and/or other serious injuries. The approach would have given scrutiny to the risk for mines that encompassed 74% of the fatalities during 2007-2010.

Jan 1, 2012

LET us return and follow our first intention of discussing the art of melting. Since I have demonstrated to you how large works are made, you may have thought that the way to the small ones was also open to you, and you would not have been mistaken. But in order to avoid work and expense there are shorter and easier ways to be used, both because the things can be handled more easily and because it is not necessary to have so much regard for the forces of small materials. Therefore, wishing to make a distinction for you, I shall call this the small art of casting. Before speaking of this, I shall tell you of several methods of making powders for moulding. Then I shall also tell you of the methods of moulding in boxes and in frames, and how the said powders are to be prepared for casting either dry or green. Then I shall tell you some methods that are held as secret by the masters for handling the metals in melting and making them flow readily, so that you may easily fill the cavities of your moulds.

Jan 1, 1942

By Franc R. Joubin, Donald H. James

"THE PROPERTY of Rexspar Uranium and Metals Mining Co. Limited is situated within 3 miles of Birch Island, British Columbia, a village on the C.N.R. main line 80 miles north of Kamloops. The claims extend up the south slope of the North Thompson River valley.Prospecting in the area dates back many years. Fluorite was reported in 1918, lead showings in 1926, and bog manganese in 1929. Diamond drilling in 1942-43 indicated more than a million tons of material containing 20 per cent fluorite and 15 per cent celestite in what is known as the 'fluorite zone'. Marketing and beneficiation difficulties have delayed further development of this deposit.Systematic checking of specimens and drill core by the B.C. Department of Mines and the Geological Survey of Canada revealed low radio-activity in the fluorite zone material. Subsequent prospecting with Geiger counters revealed zones of higher radioactivity a few hundred feet distant from the fluorite zone. The property at this stage came under the development direction of Technical Mine Consultants Limited, who undertook a program of diamond drilling. Of the several radioactive zones located, two have so far rewarded development and appear to constitute low-grade uranium orebodies. These are referred to as the ""Black Diamond"" or ""BD"", and the ""A"" zones -see section. Open-pit mining of the thick, dip-slope orebodies appears possible.General GeologyWalker (1) describes the local rocks as metamorphosed sediments cut by granodioritic intrusives and by greens tone. At the property the sequence is:GreenstoneUnconformity or intrusive contact Trachytic member -tuffs, breccia, flows. Argillite -black, thin, not always present. Schist -thin-bedded sericitic quartzite and siltstone with some calcareous layers."

Jan 1, 1949

By I. Filzwieser, S. Wallner, M. B. Hanel, A. Filzwieser

Whenever thinking about increasing tankhouse performance two major aspects has to be considered, the technological feasibility as well as the economical impact. For meeting the requirement of an increased current density leading to an increased productivity, Mettop has developed the METTOP-BRX Technology, which allows the introduction of fresh electrolyte between each pair of anode and cathode. As an example of a green field approach the installation at Xiangguang Copper Co., Ltd will be described. Since the start up in 2011, Xiangguang Copper Co., Ltd operates one of their two copper refining tankhouse with a current density of 420 A/m2 and a current efficiency above 98% in average. At Montanwerke Brixlegg Ag, as an example of a brownfield installation, the annual production could be increased by 50%. Although for many years a total of two industrial applications are in operation, the successful implementation of this technology that result in significant operational and economic advantages has not been fully accepted within the industry due to misunderstandings, incorrect interpretations and lack of awareness. It is intended with this paper to create a better understanding about the parallel flow technology and help to eliminate worries and concerns.

Mar 1, 2017

By Leo J. Miller

It is both an honor and a pleasure for me to be the keynote speaker for the Paul F. Kerr's Symposium on Applied Mineralogy. Professor Kerr was a man for all seasons to his students, and he treated all students as distinct individuals. Philip Bethke in his memorial to Dr. Kerr summed up our remembrance best by stating that "We have lost our most successful educator-administrator-scholar, who was our steadfast teacher-counselor-mentor-friend." His unique trait was the ability to bring out the best in a variety of individuals In order that their performance was at the peak of quality.

Jan 1, 1985

By Strathmore R. B. Cooke, Iwao Iwasaki, C. S. Chang

The effects of aeration on an aqueous suspension of pyrrhotite were studied and their results correlated with flotation tests using xanthates as collectors. The effects of copper activation and of pH variation were determined and possible mechanisms postulated. PYRRHOTITE has long been considered a gangue mineral to be eliminated as tailing in the treatment of various sulphide ores. However, in recent years the world-wide lack of sulphur resources has called attention to this mineral as a potential source of both sulphur and iron. Its importance as an economic mineral, however, has not been particularly emphasized. For this reason very little is known about its response to flotation, except that it can be depressed easily in alkaline circuit, by long aeration,1,2 addition of oxidizing agents,3 or by starch.' The object of this work was to study the floatabil-ity of pyrrhotite. This includes the effect of oxidation by aeration, of copper activation, and of change in pH. Preparation of the Pyrrhotite Sample: It was desirable that the highest grade of pyrrhotite obtainable be used for this experiment, since the presence of other minerals could affect the surface properties.5 However, no pyrrhotite was available as crystals, and massive deposits of hydrothermal origin commonly contain considerable amounts of chalcopyrite. Pyrrhotite concentrate was, therefore, prepared from a sulphide deposit occurring near Aitkin, Minn. The deposit is of pyrometamorphic nature consistirlg mainly of pyrrhotite and pyrite with graphite, silicates, and carbonates as gangue. The ore, already crushed through 3 mesh when received, was screened at 65 mesh and the undersize discarded. The oversize was crushed through rolls, and then stage-ground dry in an Abbe porcelain mill, the —65 mesh portion being screened out after every 15 min of grinding until all the material passed through this size. The ground product was then concentrated with a drum-type dry magnetic separator. The rougher concentrate was cleaned twice and then demagnetized. The final product was split in a Jones splitter and stored in air-tight bottles. Microscopic examination of the concentrate showed that it was relatively clean and free of pyrite, locked particles, and gangue. By means of the krypton gas adsorption method," the specific surface was determined to be 3000 cm2 per g. The chemical and screen analyses of the final concentrate are given in Tables I and II respectively. It is a well-recognized fact that the oxidation of some sulphide ores during stockpiling, grinding, and conditioning affects their flotation behavior. The problem of oxidation may become serious in the case of pyrrhotite, since this is known to be more easily oxidized than many other sulphides. To ascertain the extent of oxidation, an experiment was carried out by aerating an aqueous suspension of pyrrhotite with air, oxygen, and nitrogen as follows. A 300-g sample of pyrrhotite in 2700 ml of water was agitated and simultaneously aerated in a Fager-gren-type laboratory flotation machine. A Precision wet test meter was connected to the air inlet valve, the flow rate of the gas being kept constant at 0.3 cu ft per min throughout the experiment. Samples of approximately 30 ml each were taken from the cell at 0, 4, 10, 20, 35, 60, and 90 min. After the pH was taken, each sample was filtered and the filtrate was analyzed for total iron and sulphur. The iron was determined colorimetrically by the thioglycolate method using a green filter.' The filtrate was oxidized with bromine to convert all of the soluble sulphur compounds into sulphate and this was determined with a Parr turbidimeter." When aeration tests were made in alkaline circuit, calcium hydroxide or sodium hydroxide was added at regular intervals to maintain a constant pH. A similar procedure was followed in an experiment to determine the abstraction of copper. ion by pyrrhotite. In this case various quantities of cupric chloride were added. The filtrate from each sample taken was analyzed for copper, total iron, and sulphur. The carbamate method with a green filter was used for the copper analysis,' since this method could tolerate a considerable amount of iron in the solution. A pneumatic cell, made from a 350-ml fritted glass Buechner funnel, was used for this experiment. The detail of the assemblage has been described elsewhere." In the present work a stainless steel baffle was inserted in the cell. This baffle overcame the tendency for the coarse pyrrhotite particles to be swirled around the wall of the cell and thus fail to collect in the froth. A 50-g sample of pyrrhotite was added to the cell which contained 260 ml of water. When pretreat-ment of the sample was desired, reagents, such as activator and pH regulator, were then added and the pulp was conditioned for a specified conditioning time. Prior to the addition of the collector approximately 15 ml of the solution were removed for pH measurement and for iron and sulphur analyses. Copper when used as activator was also determined. Collector and frother were then added and the pulp was conditioned for an additional 2 min. Air was admitted to the cell and the froth removed. The separation required from 4 to 6 min, depending on the characteristics of the froth. The float and non-float products were filtered, dried, weighed, and assayed for iron.

Jan 1, 1955

By Bruce D. Hebb, Shahin Shadlou

Fiber Reinforced Polymer (FRP) is an excellent material choice for a broad spectrum of corrosive fluids and, in many cases, offers the best value per dollar. FRP Flanges present the greatest design challenge of all standard piping components. The theory underlying the design of flanges is very complex. In addition, due to the nature of FRP material, proper fabrication of the flanges is as critical as the design. In this review, the challenges of making FRP flanges along with the design techniques and best practices of fabrication that will lead to a high-quality flange will be discussed.

Feb 1, 2024

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, NIOSH conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the research, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This document highlights NIOSH's research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers, and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan, and if appropriate training is provided. DISCLAIMER: ?The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.?

Jan 1, 2009

Maximising margins in today's competitive international commodity markets demands superior productivity. This requires more than simply selecting the best equipment. It requires efficient production and commercial processes together with management systems recognised as international best practice. This paper introduces an integrated way of working that includes management systems for successfully changing work practices and attitudes, developing managers and increasing accountability. It provides an improvement methodology that includes systematic involvement of people in true continuous improvement of processes for maximising productivity and safety while minimising costs. Even though the principles are proven in all industry sectors worldwide, they are not always used correctly. This paper provides examples of traditional performance measurement systems to show how managers miss opportunities to control and improve both production and supporting service processes. It also describes the basic methodology for correct use of the principles and provides examples of correct implementation of modem systems in mining. The charts from actual mining case studies will be elaborated upon in the conference presentation. This paper's main aim is to provide background material for the presentation by introducing integrated principles for building best practice management systems for superior productivity and safety - for higher margins.

Jan 1, 1996

By Leonard W. Postregna

Prior to January, 1986, the city of Austin, Texas was on notice by the Federal Government's Environmental Protection Agency and the Texas Water Commission, that they were illegally polluting the Colorado River. The wastewater facilities presently in use in South Austin were inadequate to handle the vastly increasing population. The city of Austin, Texas hired Parsons Brinckerhoff Quade and Douglas, Inc. and Dannenbaum Engineering Corporation to design and supervise the construction of an update to their existing system to alleviate this problem. A major criterion handed down to the Designer and Contractor was that the system had to be completed within a two year time frame. The biggest link to the entire design was a tunnel project consisting of 43,000 linear feet (13,106 m) of tunnel, eight feet (2.44 m) in diameter with connecting structures tying into existing and future facilities. The project was awarded to S. A. Healy Construction Company of McCook, Illinois with a low bid of $24,755,000.00. This article summarizes the techniques used in the construction of this tunnel project.

Jan 1, 1989

By Anthony J. Chasteen

Although geothermal energy has been used by mankind for thousands of years and has even been used to generate electricity since the turn of the century, it is only in the last few years that the threatened energy crisis has focused attention on this resource. Geothermal exploration and development is being carried out in at least thirty-five countries on five continents. The status of geothermal energy production, however, is rudimentary with about 800 MW installed generating capacity worldwide, equal to about 0.1% of the world's total energy production.' The world's first (1904) commercial generating site at Lardarello, Italy, will soon be surpassed by developments at The Geysers, Calif. There are other successfully operating geothermal power projects in New Zealand, Japan, USSR, Mexico and Iceland with pilot plants planned or under construction in Chile, El Salvador, Nicaragua, Turkey and the Philippines. The preponderance of exploration and development is being sponsored or assisted by individual governments, by the UN or by the U.S. Agency for International Development

Jan 10, 1972

Develop a cost-effective diesel aerosol sampler that can be used by industry and regulatory agencies to determine the diesel exhaust aerosol concentration in mine atmospheres. The sampler must be easy to use, wearable by mine personnel, compatible with current personal sampling protocols, and inexpensive. Approach The University of Minnesota (University) and the U.S. Bureau of Mines (USBM) have developed and tested a prototype diesel exhaust aerosol sampler. The sampler, however, was complicated and expensive to fabricate. Consequently, the USBM redesigned the sampler to simplify both manufacturing and use, and the sampler was evaluated to ensure equivalency with the prototype. Background The National Institute for Occupational Safety and Health (NIOSH) has recommended that "whole diesel exhaust be regarded as a 'potential occupational carcinogen,' as defined in the Cancer Policy of the Occupational Safety and Health Administration." In addition, the U.S. Mina Safety and Health Administration (MSHA) has been directed by an advisory committee to establish a diesel exhaust aerosol standard and regulations to minimize exposure to diesel pollutants in underground coal mines.

Jan 1, 1992

The Northwest Territories (NWT) of Canada has emerged as a major new province for diamond mineralisation in less than three years. This is primarily the product of a diligent search in the form of a scientifically based exploration effort. However other factors, including positive aspects of the business and the legal environment have also been identified as assisting the exploration process. In my view these have increased the likelihood of diamond mining becoming a major new industry for Canada. The supportive role of various government agencies has been important. In addition, the character of many of the joint venture deals that have been done has provided an attractive setting for the capital intensive evaluation and development work that is now required to bring the diamond discoveries into production. Perhaps of equal importance is that with the recognition that is being given to the success of the NWT diamond ventures, Canadian explorers are continuing to attract new risk capital for further exploration. This paper attempts to model and quantify the probability of exploration success translating into successful mine development.

Jan 1, 1994