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General economic conditions continued to improve in the second quarter of 1984 as real gross national product advanced at an annual rate of 7.5 percent (table 1). This followed an even larger first quarter annual rate increase of 10.1 percent. The slower second quarter growth was greeted as a sign that the economy is not over-heating. The signs of slowed growth in some sectors suggest that the recovery may continue well into 1985 without the inflation symptomatic of a rapid recovery. Most of the slowdown in growth was absorbed by business inventories, personal consumption of durable goods, and residential fixed investment. Business inventories grew by only 68 percent as much as in the first quarter, personal consumption for durable goods grew by 58 percent of the first quarter rate, and residential fixed investment slowed to only 44 percent of the first quarter growth. Sectors with accelerated growth in the second quarter included personal consumption of nondurable goods and of services, which increased at annual rates of 9.6 percent and 3.8 percent, respectively, and Federal purchases of goods and services, which increased at an annual rate of 47.9 percent.

Jan 1, 1984

By Dean S.

Further discussion at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 12th February 1916, with Mr. T.Y. Greener, President, in the chair, of the paper published in Trans. I.Min.E. vol.L, 1915, p.179 and 388. Written contributions to discussion included Mr. Dean's reply to earlier discussion (p.35-44), further written contributions by Tate S. (p.44-54) and Brown E.O.F. (p.54-56), and oral comments by Hare S., Merivale J.H., Greener T.Y. and Tate S. Particularly debated were the causes of the difference in output between American and British coal miners

Dec 1, 1916

By Mark R. Pettitt

The results of an extensive research and development program to reduce the noise generated during coal cutting are presented. The characteristics and magnitude of continuous miner coal cutting noise sources are defined. This work consisted of development of a simulated coal ,cam to facilitate above-ground coal cutting tests, noise measurements in a reverberant acoustic chamber during simulated mining operations of a continuous miner (cutting the simulated coal scam), and noise measurements in an underground coal mine during continuous miner operation. In-mine and laboratory test results were in excellent agreement for both A-weighted overall levels as well as A-weighted one-third octave band spectra. Methods to reduce coal cutting noise are presented. These methods take full advantage of the dynamic characteristics of the forces generated during coal cutting. Dynamic cutting force isolation was shown to be a very effective technique. Finally, a continuous miner was equipped with a cutter head that incorporated (among other design factors) cutting force isolation. Successful, lung term, in-mine use of the cutter head demonstrated coal cutting noise at the operator's station of less than 90 dBA and 50% coal, 50% rock cutting of less than 93 dBA.

Jan 1, 1985

By Morris Steinberg, John Wulff, Robert Kamm

IN powder metallurgy it has often been observed that shrinkage may occur in one direction and growth in another during sintering. Even in long-time sintering experiments the rate of shrinkage may be different in different parts of the compact. In the fabrication of some parts requiring a constant permeability it is even questionable in some cases whether pressing from one direction should be attempted. These observations require for their interpretation a more detailed study of green or pressed density than has heretofore been available. Usually average density measurements of the whole compact are made and in some cases carefully cut sections are measured. A different approach to the problem was first mentioned by Rakowski1 and also used by Balshin.2 Balshin's diagram is reproduced in Fig r and schematically shows the result of pressing three layers of metal powder with fine intervening layers of graphite. The retarding effect of the die walls and a qualitative example of the density distribution is evident. More quantitative information about the distribution of density within a cold-pressed powder compact would be useful in showing the variation in density in compacts as influenced by the type of powder, shape of die, lubrication during the process, and other variables. Furthermore, information about the cracking of cold-pressed compacts may be obtained from an analysis of the stress distribution within a powder compact, and some information about the stress distribution can be obtained in turn from the density and strain distributions. A more detailed report on some of the present experiments appears in reference 3. PRESENT INVESTIGATION In order to ascertain the density gradients in cold-pressed metal powders, a deformable lead grid within the powder was employed. After pressing in cylindrical dies the ejected compact was radiographed, giving a pattern of the deformed grid. From the radiograph density and deformation from point to point is readily measured. From the radiograph strain distribution and stress trajectories were also determined. The latter also permits the determination of the coefficient of friction at the die wall. This technique indicates that the densest part of a compact pressed from one side is at the top outer circumference and the least dense region at the bottom circumference near the stationary plunger. For some heights of compacts the density at the axis is such that the lower density is at the top rather than at the bottom. So irregular a density distribution is due primarily to die-wall friction. As the ratio of diameter to height of compact is increased the die walls play a correspond¬ingly smaller role. More uniform density

Jan 1, 1947

By M. Ataee-pour, S. E. Jalali

So far, a large number of algorithms have been developed for the optimization of pit limits, most of which follow deterministic rules. In this paper, a new algorithm is introduced, which follows a probabilistic logic using the Markov chain process. The algorithm is implemented on a transition matrix that corresponds to the 2D conventional economic block model of the mining area. The probability of mining a block is proportional to the desirability it may provide. Applying this algorithm, the probability of mining each block is obtained, and finally, the optimum pit limits are defined as the pit, which provides the highest probability of mining. In order to validate the proposed model, a numerical example is given and the results of the algorithm are compared to those of a dynamic programming algorithm. A 2D analysis of the problem is discussed in this paper. Although dealing with 3D problems requires larger size matrices, the optimization method is the same and the algorithm does not need any smoothing.

Jan 1, 2006

Past issues of Minerals and Materials have discussed such aspects of the economy as consumption and investment expenditures, interest rates, productivity, and international trade barriers and their effect on the minerals industry here and abroad. In this issue, we will (l) look at recent indications of a possible economic recovery, (2) present 1983 expectations reflecting the results of industry surveys conducted by the U.S. Department of Commerce (DOC), and (3) briefly discuss the contribution of the U.S. mining industry to total gross national product (GNP). THE RECOVERY Throughout most of 1982, DOC's Composite Index of Leading Indicators provided evidence of impending improvement in the economy. The index increased moderately during eight of the months in 1982 and then jumped an estimated 3.6 percent in January 1983 (table 1). While the leading indicators continued to predict improvement, the general economy, as measured by the Index of Industrial Production, continued its slide through November 1982 (table 2). Finally total industrial production increased in December 1982 and continued on an upward path in January and February, as predicted by the leading indicators.

Jan 1, 1983

By J. D. Sargent

Selenium might be described as a paradoxical element, being either a metal or a nonmetal, a conductor or nonconductor, amorphous or crystalline, colorant or decolorant, and a hydrogenator or dehydrogenator. Selenium was discovered in 1817 by the Swedish chemist, Berzelius, while studying flue dust from the lead chambers of the sulfuric acid works at Gripsholm, Sweden, The ordinary stable form of selenium is a crystalline, grayish solid with semi-metallic luster. It melts at 217° C., boils at 684.8° C., and has a density of 4.79.

Jan 1, 1955

By J. W. MacDonald

Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review, These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work.

Jan 1, 1960

By Karl C. Dean

The Bureau of Mines stabilized 10 acres of windblown copper mill tailings at McGill, Nev., by a combination chemical-vegetative procedure. Legumes, winter wheat, wheat-grasses, and wild rye were seeded, and the area was subsequently sprayed with a resinous adhesive chemical to stabilize the sands until the vegetation could grow. During the year since treatment, the area has been well stabilized against wind erosion. The established vegetation appears to be capable of self-perpetuation and renewal without irrigation. The cost of stabilizing the area was $135.50 per acre.

Jan 1, 1969

By Vernon Helm, John S. Ball, Welton J. Wenger, William E. Haines

"INTRODUCTION Although the presence of sulfur causes many petroleum’s to be classified as ""low-grade"" because of the difficulties encountered in manufacturing products to meet rigid specifications, the petroleum industry is finding it necessary to use such crude oils to satisfy present needs. As the demand for petroleum products increases, and available reserves diminish, this utilization of high-sulfur crude oils will be accentuated. Programs designed to supplement the supplies of fuel available from petroleum by the manufacture of synthetic fuel from natural gas, shale oil, and coal are in progress. Such fuels, especially shale oil and, less so, oil from the hydrogenation of coal, also contain sulfur compounds which must be effectively removed. Thus, the need for fundamental research on the sulfur compounds that may be expected in petroleum and allied products is becoming greater as the industry is forced to call upon all available resources to meet the demand for petroleum products. In recognition of this need, the Bureau of Mines has inaugurated a long-range program assigned to furnish fundamental data concerning the presence, characteristics, and effects of sulfur compounds in petroleum and its products."

Dec 1, 1946

By E. F. Koppe

The Upper Freeport coal in the Freeport and New Kensington quadrangles, Pennsylvania, varies from a bony streak to a thick coal deposit often exceeding ninety inches, the "Double" or "Thick Freeport". Distinctive basal partings, a central bone layer, and a canneloid top bench may be present. The appearance of a sandstone roof, sandstone rolls, and bony coal at the top of the main coal bench can be anticipated in thin Freeport areas when basal partings are absent. When the two basal partings are present, a shale roof is normal. These effects are correlated with the original topography upon which the coal was deposited. The original depositional high areas tend to coincide with present structural highs. Preliminary data indicate that coal quality, in part, is affected by the deposi-tional setting. In "high" areas, a tendency exists for the main coal bench to contain higher percentages of fusain and mineral matter. Within limits, some-what higher ash fusion temperatures appear to correlate with paleotopographic highs. As a result of these findings, critical examination of the paleotopography and related sediments is indicated in other areas and other coals. The Upper Freeport coal is quite variable both in thickness and composition in the Freeport and New Kensington quadrangles of Pennsylvania (Figure 1). The coal horizon in these quadrangles is marked either by a thin carbonaceous shale bed or by a single bed containing a variable number of partings (binders). The complex coal zone known locally as the "Double" or "Thick Freeport" contains the Upper Freeport Coal Bed at the base; but in addition, it has an overlying bone layer and an upper coal bed occasionally capped with a canneloid layer. The "Thick Freeport" often exceeds 90 inches in thickness, whereas the normal Upper Freeport coal usually varies between 34 and 50 inches.

Jan 1, 1961

By C S. Kelsey, J R. Kelly

Australia is presently enjoying the fruits of a booming iron ore market. Expectations are that market strength will be supported in the short to medium term by increasing feedstock demands from steel mills, as world economies rebuild post-Covid-19. However, as cost and environmental pressures increase the longer-term market outlook will be dominated by product quality. The ‘flight to quality’ will place increasing demands on direct shipping ore miners as they compete to maintain their standing in the iron ore marketplace. China will progressively disengage from its dependence on Australian imports, leaving miners under increasing pressure to boost product quality and diversify outlets globally. Australia has vast deposits of low-grade magnetite ores located mainly in remote and arid regions of the continent. This paper proposes a dry grinding and magnetic separation process to produce premium concentrate grades from the low-grade ores, to assist in meeting future product quality demands. The premium grade concentrates could be either blended with lower quality direct shipping ores or marketed separately. The proposed dry concentration process involves the pairing of Vertical Roller Milling (VRM), a mature technology widely used in the cement industry, and Planar Magnetic Separation (PMS), a new methodology, which has been developed to the threshold of commercialisation by the private Australian company Cyclomag P/L. Two laboratory prototype planar magnetic separators with field strengths of 1800 gauss and 6000 gauss have been built and tested on a range of magnetite ore types over the past three years. In each case, following grinding to liberation sizes, a combination of roughing and cleaning operations has produced pellet grade concentrates. Vertical roller milling has competed successfully with conventional media milling in grinding cement clinker, limestone and blast furnace slags. A key advantage of dry VRM/PMS processing is its potential adaptability to stepwise modular development, which can minimise initial capital investment, while generating early revenue streams to cope with unpredictable market volatility.

Nov 8, 2021

By Harold J. Bennett

The purpose of this study was to develop methods for the financial evaluation of mineral deposits. This includes the selection of the best alternative mining and processing methods and production rates. This was done by performing a financial evaluation through computer simulation using sensitivity and probabilistic risk analysis. The criterion used to measure the relative advantages of these investment and operating alternatives is the discounted-cash-flow rate of return. Included is a description of the theory and methods used in the probabilistic analysis approach, which is based on the premise that the expression of a range of values in establishing an estimate for a parameter is more realistic than the choice of a single value. Numerous simulations are made using randomly selected values of the input parameters resulting in a frequency distribution of the rates of return and their relative probability of occurrence. The sensitivity analysis method is described and combined with the probabilistic analysis to interrelate mineral reserves, capital investments, operating costs, and production rates. The ability to vary these input parameters on successive runs has permitted the selection of the best alternative mining and processing methods and production rates for a given mineral deposit. For illustrative purposes the evaluation of a mineral deposit was performed using three alternative mining and processing methods at three different quantities of resources and various production rates and prices. The computer program used in this analysis was written in FORTRAN II for maximum compatability and should run without modification on most computers having BK (8,000-word) core memory, a card reader, and printer (120 characters per line).

Jan 1, 1970

By A. B. Hooker, L. C. IlsLey

"The last previous Bureau of Mines publication relative to details of permissible electric mine lamps is Bulletin 332, which describes 16 lamps approved prior to May 1930. Some of the lamps have become obsolete through the development of improved models which, with several new types, make it desirable to supplement the Bureau's published data relative to permissible electric mine lamps.In the following descriptions, lamps approved since May 1930 and prior to July 1, 1935, are placed in the three following groups: (1) Electric cap lamps, (2) electric hand lamps, and (3) lamps for miscellaneous applications,ELECTRIC CAP LAMPS APPROVED UNDER SCHEDULE 6B1. Edison model J lamp, approval no. 24. - The features that distinguish this lamp from earlier models of Edison electric cap lamps are:(a) The battery consists of two F-2 cells of square cross section and about 1-1/4 inches higher than M-14 cells in the model H lamp, making the battery narrower and higher than any of the earlier models of Edison cap lamps.(b) The cells are insulated from each other and the Monel-metal casing by enclosure in vulcanized-rubber baglike enclosures. Both cell terminals are insulated from the cell jar.(c) The battery is equipped with rubber-tube Bunsen-valve-type gas vents.(d) The battery casing is secured by a new-type magnetic lock.(e.) The battery and cover terminal clips have been redesigned to give a wiping contact."

Jun 1, 1936

By H Arvidson, A Walker, N Pollock

Following the recent tailings tragedy in Brumadinho, the Investor Mining and Tailings Safety Initiative was formed representing institutional investors in the mining industry. This Initiative, led by The Church of England (CoE), requested data from 726 mining companies on each of their Tailings Storage Facilities (TSFs). What this exercise confirmed was that there was no public database of TSFs, and that there was a clear gap in tailings management systems within the disclosing companies. We present an approach using technology to support best practice TSF management, governance and disclosure which was originally submitted as part of University of Cambridge Post-graduate studies in Sustainability Leadership in January 2020. The aim of the paper is to discuss how technology could be used to deliver a Tailings Management Solution (TMS) that is aligned with the Global Industry Standard on Tailings Management (GISTM), and supports rigorous governance leading to disclosure. Subsequently the goals of the plan are aligned with that of the co-conveners of the GISTM (the International Council on Mining and Metals (ICMM), Principles for Responsible Investment (PRI) and United Nations Environment Program (UNEP)) which is to facilitate operators’ trajectory towards zero harm to people and the environment. Most of the focus to date around tailings management post Brumadinho has been on monitoring technologies, of which there are many. It is obviously important to acknowledge the critical role of monitoring technologies; however, our approach is agnostic to monitoring technologies and assumes that all of them are relevant. Our focus is on the data management, reporting and governance leading to disclosure of the information. Critical components of developing the TMS include adapting existing software products and solutions, recognising a system thinking approach is needed, strategic partnerships to deliver an accessible solution faster and more cost effectively, and, new ways of collaborating. The TMS should also accommodate relevant regional geotechnical codes and standards. The industry need for a TMS is well established and urgent, with significant pressure from regulators and civil society for the industry to address this significant issue.

Jul 1, 2021

By Art Cooper

Granulation systems are customarily viewed as problem areas in metallurgical operations. The inherent risk of explosion when combining a high temperature melt with water creates a safety hazard. Separation of the granulated material from the quenching medium generally involves equipment that can have significant maintenance and operating costs. Granulation systems' reliability and availability can negatively affect the plant production. Against this background, granulation systems have been treated by design firms and producers as an add-on and a necessary evil. The technology is becoming better understood and solutions to common problems are being found. This paper will discuss typical problems in common systems, and some of the improvements that have been made, with particular reference to non-ferrous applications.

Jan 1, 2006

By G. R. Phare

Explosives formulation is dictated by desired field performance, which in turn is dependent on such physical properties as strength, velocity of detonation, sensitivity, and water resistance. The design of explosives to obtain these properties is discussed with some reference to detonation and rock mechanics theory.

Jan 1, 1958

By William W. Aljoe

This report summarizes the Bureau of Mines noise-control research program from 1972 to 1982. Each segment of the mining industry--under- ground coal, underground hardrock, surface mining, and processing plants--has different noise-control problems because of vast differences in working procedures, equipment, and workplace design. The Bureau has identified the most serious noise problems in each segment and has developed strategies for attacking these problems. This publication points out the need for noise control in the mining industry, discusses Federal regulations governing worker exposure to noise, and describes the Bureau's overall approach to mining noise- control research. It traces the history of noise overexposure in each segment of the mining industry and discusses the major noise sources. It provides detailed information on noise-control research efforts in the Bureau's major areas of emphasis, including the results of these efforts. Finally, the report discusses the Bureau's future role in research on mining noise control, emphasizing the need to expend more effort on long term in-house investigations into the noise problems that have been identified in past programs as the most serious ones.

Jan 1, 1985

"History - How did you get into mining and involved with SME?Unlike many past presidents, I do not come from a mining lineage. I liked math in high school and believed I wanted to be an engineer. I told my math teacher that, and he laughed in my face. I believe that humiliation is what carried me through engineering school. At the time my ability to go to college relied on how inexpensive I could make it. My brother told me that there were a lot of scholarships in mining engineering, and I should apply to mining schools. As usual, he was right and I was off to the University of Idaho to study. My first summer break I got a job with Hecla at a mine in Arizona. I was a laborer on a shotcrete crew. I knew after the first summer that I loved underground mining, and I never considered changing disciplines. Looking back, I was working in miserable conditions (hot, humid), on a miserable job (shotcrete), where I got injured, and two summer student roommates died in a car accident on the commute home after work. I had every reason to hate the industry, as I had seen virtually everything bad about what we do. But I didn’t, I loved it. I said I was good at math, I never said I was smart.I joined SME in college because I was told to by the head of the mining school, Dr. Jack Hoskins. You did what Jack told you to do. I got involved because I went to an annual meeting and the papers in the underground sessions were terrible. I refer to bad papers as the “Tensile strength on cable bolts in sub-arctic regions on Tuesday” papers. Real snoring fodder. I don’t remember who I was complaining to, but they told me to quit my grumbling and fix it. So I chaired a session, and tried to get only good quality papers, something that has been my mantra for years with the Mining & Exploration Division. I also volunteered to help the local sections too. Then one day I woke up as president.What is your opinion of the health of the mining industry?The mining industry is in bad shape. Coal is under attack and will likely never recover to its former greatness. Our President has banned new coal leases, and the state of California is forcing people it does business with to divest their interests in coal companies. And that all happened in just in a few short weeks this January. Usually in America you get a trial before you are given a death sentence, but not with coal."

Jan 1, 2015

By Alexandra Anderson

A computational fluid dynamic (CFD) model has been developed using ANSYS Fluent 17.0 to help identify areas of high wear within the refractory lining of a secondary lead reverberatory furnace. Once a base case simulation was validated using data from an operational furnace, areas of potentially high refractory wear were determined through the calculation of the temperature and velocity distributions within the furnace and on the hot face of the refractory lining. The CFD model was used to assess whether the predicted areas of high refractory wear could be minimized through changes burden geometry. The results showed that shape of the burden geometry greatly affected the overall flow patterns and heat transfer within the furnace.