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By Francis Cameron

Gloomy predictions that domestic mineral reserves are approaching exhaustion are unwarranted and may be harmful, this author contends. Specific mineral forecasting errors in the Paley Report are cited to support this contention, and steps that can be taken to insure a progressive mineral industry capable of keeping pace with the major raw material needs of the nation through advancing technology are suggested. Mining is both exciting and rewarding —although at times somewhat frustrating— and we all can have real pride in our industry, in its people, and in its accomplishments. It is, however, with concern that I have noted a deterioration in this Country in what might be called mining's stature and in the growth of a belief in many quarters that our mineral reserves are rapidly approaching exhaustion. In other words, there is a popular image that we are fast becoming a "have not" nation in many respects and that the domestic mining industry can no longer be considered, in the vernacular of Wall Street to offer much in the way of "growth potential." I do not subscribe to this hypothesis, nor do I be-li4ve that the record of the mining industry bears this out. However, let me add that we can, in time, talk ourselves into this frame of mind and we can hasten the day when this very well might come about by unnecessary and unwise legislation or regulation. My remarks today are basically designed to give my reasons for refuting this negative philosophy and to review our record. With your help, I know we can improve our image, and the public's recognition of our industry's peculiar problems. The progress of our civilization over the centuries has been fundamentally based upon proper use of raw materials, both agricultural and mineral, and upon energy, human or otherwise. As the standard of living has progressed century by century, the demands for mineral raw materials have increased in an irregular, but steadily rising progression. Fortunately, those minerals on which we depend most, i.e., iron, coal, petroleum, copper, aluminum, lead, and zinc have been neither too difficult to find nor to process into useful form. Iron, the most useful of all metals, is present in various amounts in most rock types and soils. Gold, seemingly the most generally desired (but certainly not the most useful of all metals), occurs in sea water in a far greater total tonnage than has been won from all of the world's known gold mines. If the latter is true, then why do we not see large installations treating sea water for the recovery of its gold content? The answer, of course, is that even the French, who seem, from their recent actions, to value gold above all else, have not devised a way of doing this at a profit. Theoretically, it is possible, but not with today's technology at a cost which would justify the effort. Man has exploited only those mineral concentrations which accidents of nature have placed within his so far limited means of finding and utilizing. What we geologists and engineers refer to as an orebody is nothing more than a concentration of minerals, exploitable with available knowledge, that will yield a value greater than the value attached to the energy and capital required to produce it. What is "ore" and what is not "ore" is, in the end, a matter of economics. The economic problem stems from the physical and chemical character of mineral deposits. The good Lord stacked the cards heavily in favor of rising costs by limiting the amount of the higher grade ores easily available. As the best and most accessible ores are depleted, it becomes necessary to work harder and with greater ingenuity to produce more from less accessible and lower grade resources. The quantity of mineral raw materials we can have in the future will be determined largely by what we can afford to pay for them in terms of human effort, capital outlay and production energies. We will always have the problem of cost with us and our only real means of keeping ahead of rising costs is by continually improving our technical abilities. We, in this country at least, no longer have open to us large and unexplored virgin wildernesses in which a pick-and-shovel prospector might uncover an untouched mineral bonanza. The rest of the world also has few conventional frontiers left in which the explorer-prospector is free to roam. We do, however, have enormous land areas unexplored, and untouched po-

Jan 1, 1969

All too often engineers and project teams focus on building æthingsÆ, and they tend to see the key goals as meeting the project cost and schedule targets. We frequently compound the problem by unknowingly rewarding engineers for building bigger, more complex, more æbullet proofÆ and hence more costly æthingsÆ. Unfortunately the end result all too often ends up being a disappointment in terms of business performance. The term æshareholder valueÆ may never have entered the discussions during the development process. This paper deals with the fundamental issues, which tend to pre-dispose new developments to success or to failure. As project management concepts are not particularly complex, it begs the question why is it that the failure rate of new developments is so high? It is argued that the answer lies more in people behaviour issues than in project management tools and processes.

Jan 1, 2002

By L. R. Moore

The World Health Organization (WHO) considers contamination from oxyanions, such as selenium and arsenic, a global concern. While their elemental forms are toxic, the aqueous oxyanions are more so. These aqueous forms, which exist at a higher oxidation state, are the most common forms released during mining processes. Many technologies are capable of meeting the governmental discharge criteria for oxyanionic contaminants, but may possess limitations due to redox chemistry as well as the water matrices. An innovative technology was developed that can successfully reduce such aqueous forms generated during mining processes to a level below the discharge criteria. This paper discusses how an understanding of the sensitivities of this novel adsorbent towards these variations in water matrices and redox chemistry can be used to optimize its application.

Feb 27, 2013

By Adam Zanker

Smooth roll crushers are widely used as secondary crushers, operating most effectively when set for size reductions in a ratio between 3 or 4 to I. The feed supplied to these units varies from 13 to 102 mm in size and the product obtained ranges from 13 mm to about 20 mesh. Smooth roll crushers produce very few fines and absolutely no oversize. The diameter otfhe rolls varies with the clearance between them, feed size, and the coefficient of internal friction ofmaterial to be crushed, Detailed calculations of this relationship may be found in Unit operations of Chemical Engineering, (McCabe, W. L., and Smith, J. C., 1967, McGraw Hill, NY, Chapter 26, pg. 825). The geometrical arrangement of the roll crusher is shown on the accompanying sketch. A relatively simple relationship between the diameter of feed, the roll, and the gap between them is as follows:

Jan 6, 1980

By Clyde Williams

IF you would allow me some liberties, I would restate the title of this talk as "Scientific Research, Our Greatest Resource," because that title would represent more clearly a present-day conception of the metals and minerals situation. It is a subject worthy of careful consideration. Canada and the United States are so similar and interdependent in their national economies that, in the following discussion, examples of conditions in the United States may be interpreted to apply to Canada as well. Moreover, it is a striking fact that the per capita value of mineral production in Canada and the United States in 1940 was almost the same. Therefore, in the consideration of this subject, I have made no attempt to differentiate between the two countries. Consumption of the world's mineral resources in the last few decades. and particularly during World War II, has been so enormous as to require some form of magic to ensure the continued progress of civilization in the face of a diminishing supply of these resources which are so critically essential. As C. K. Leith pointed out, in 1941, indus-

Jan 1, 1947

By G. D. Schena, C Chiaruttini

The feasibility is demonstrated of reconstructing the volumetric distribution of liberated particles and middlings by use of a damped, weighted least-square regularisation method. This allows a precise mass balance to be obtained around a separation/concentration unit, permitting evaluation of the partition curve (Tromp curve) of the separator. Areal grade measurements are made on polished sections of feed, concentrate and tailings and a kernel-based inversion technique is then used to obtain the volumetric grade distribution of the three assemblages. A plain kernel (number of occurrences) and a weighted kernel (each occurrence counted with its area) are used for the solution. Testing of the method on computer-generated synthetic areal grade measurements indicates that it offers a valid alternative to the tedious conventional procedure of conducting experiments with heavy liquids

Jun 21, 1905

By Paulo Roberto Gomes de Sousa

O trabalho mostra a analise de energia e exergia de uma unidade termoelétrica, esta planta consiste em um ciclo regenerativo. Serão comparados os nivéis de irreversibilidade dos componentes que compõem a unidade. A escolha do ciclo regenerativo com a referência em análise, é devido sua eficiência global. Isso é proporcionado através do aquecimento da água de alimentação da caldeira, com isso, consequentemente ocorre uma diminuição da necessidade de energia imposta na caldeira. A análise realizada também mostra as irreversibilidades da planta através da análise de exergia.

Aug 17, 2017

By G J. Lyman, F S. Bourgeois

As the prices of metals slide, financial control of mineral processing operations becomes more and more important. Control of a mineral processing operation implies measurement of grades, recoveries and losses, with every effort being made to recover more product from the same feed. Shareholders become more concerned with the transparency of the operations and the corporate governance.There is only one way to achieve this and this is by sampling and making good use of the results of that sampling. Sampling systems that provide only 'rough' figures are not good enough. Similarly, a competitive position in the marketplace demands close control of product quality. Maximisation of product output demands that the product just meet the specification so that product yield is maximised. Decisions based on precise sampling results carry less risk that those based on imprecise results.This paper reports some recent advances in sampling theory that permit full quantification of sampling distributions, not just the sampling variance as has been possible in the past. These advances can be used together with simulation methods to tie down sampling precisions and develop calculations that quantify decision making risk when using the sampling results. A number of examples illustrate the use of the new advances and a final example indicates the development of risk analysis curves in the coupling of sampling precision to sale of a commodity.CITATION:Lyman, G J and Bourgeois, F S, 2015. Sampling, corporate governance and risk analysis, in Proceedings MetPlant 2015, pp 27–34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By R. H. Hiltz

One of the major hazards in underground coal mining is fire. The inherent hazard of fire is exaggerated by the nature of coal mining restricted areas, the highly combustible nature of coal itself, and a potential for explosive concentrations or dust and gas in the air it becomes imperative therefore to make every effort to eliminate the causes of fires, while providing the most effective means possible to control and extinguish those fires which may occur it has been demonstrated by prior work that the problem of control increases in proportion to the time necessary to institute control procedures. There are several areas of underground coal mining with obvious fire potential. Some of these, like belt heads, have reliantly undergone improvements in standby fire control devices Others, although having fire suppression systems available to them, have not received as complete a systematic study of their problems. Face machinery, particularly those without a water supply, falls in this latter category.

Jan 1, 1973

By T. A. Ring

The bed filtration of colloidal particles has been modeled by performing a differential particle balance. The balance considered the localized particle deposition rate to be the sum of three rate resistances: 1) mass transfer to a region near the surface; 2) adhesion onto a partially filled surface; and 3) resuspension from a partially filled surface. The differential particle balance equations, one for the free particles and one for the adhered particles, were solved by a finite difference algorithm. The results of this model are compared to experimental filter breakthrough curves.

Jan 1, 1983

The relative abundance of coal in India compared to other fossil fuels makes it a natural choice as the primary source of fuel, be it for steel making, power generation or for other uses. The wide variations in nature and type of Indian coals formed during lower Gondawana period and categorized as difficult-to-wash due to its typical mineral matter association with the organic matrix call for suitable beneficiation techniques as the preferred option for quality upgradation. The good quality coking coals of the upper seams are fast depleting leaving behind the inferior quality lower seam coal. The lower seam coals presently being mined are mostly low volatile coking coal (LVC). They constitute about 50% of the total coking coal reserves in India. The beneficiation of Low Volatile Coking coals pose a major challenge and detailed R & D studies was taken up to study the beneficiation characteristics of these coals. The studies revealed that the liberation characteristics at coarser sizes are very poor and the coal is to be ground to finer sizes for liberation. The most important factor that determines coal cleaning efficiency is liberation of organic matter from mineral matter. To achieve liberation grinding is necessary as a result range amount of ultra fines (-0.063 mm) coal is generated. Presence of these large amount of ultrafine in the coal fines, often impose severe technical constraints affecting not only its floatability but also in the downstream treatment of the products like dewatering and cake formation particularly when it is beneficiating through froth flotation. In the present paper optimization of ultra fines (-0.063 mm) has been tried for a LVC coal of Jharia coal field for the better liberation and beneficiation of the above coal fines. It is observed that by optimized, combination of size and number of balls generation of fines can be controlled with liberation. Keywords: coking coal, liberation, floatability, dewatering

Sep 1, 2012

By C. J. Chindgren

Upgrading of commercial red cake and recovery of vanadium oxide from uranium-vanadium mill solutions were investigated by the Bureau of Mines. Alternative procedures potentially useful for manufacture of high-quality vanadium oxide at the mill site were explored and developed. The simplest and best procedure for converting commercial red cake containing about 10 percent combined sodium and potassium oxides (Na20) (K20) into a 98- to 99-percent vanadium pentoxide (V205 product appeared to be a metathesis in an ammoniacal solution of ammonium sulfate. Molybdenum, as well as the alkali metal oxides, was removed from the red cake by this procedure at a modest expenditure of labor and reagents. When preparing vanadium oxide of higher grade, it was necessary to dissolve the red cake and reprecipitate the vanadium as ammonium metavanadate. Calcination at 450° C, decomposed the metavanadate and yielded oxide of about 99.5 percent V205. By recyrstallizing the metavanadate before decomposition, an oxide product approaching 99.9-percent purity was obtained.

Jan 1, 1962

By G. W. Weems

The specific objective of this investigation was to determine the compressibility factors for helium and carbon dioxide mixtures at -10° and -20° C and pressures to 1,000 psia. A Burnett apparatus was used. Data from the experiments were treated by the method of Barieau and Dalton. Tables of compressibility factors and approximations of the virial coefficients are presented for 10 binary mixtures as well as for helium and carbon dioxide. The results follow the same trend as data previously reported.

Jan 1, 1970

By B. Spigarelli

Carbon dioxide sequestration by conversion to carbonates has become a promising option for CO2 storage. Experiments were conducted to determine the feasibility of CO2 sequestration at ambient conditions using a Ca-rich industrial waste in a carbonate solution. The Ca-rich industrial waste used in this study was lignite fly ash. Fly ash was chosen because it is cheap, available near large CO2 point sources, already in powder form, and reactive due to amorphous properties. In the experimental set-up, CO2 absorption was inferred by monitoring feed and exhaust gas CO2 concentrations. The addition of an alkali to a fly ash-distilled water solution provided a 50% increase in CO2 absorption of the solution. Absorption time also increased by 50% compared to a fly ash-distilled water solution. TGA analysis was used to determine the extent of CO2 sequestration in the carbonate form. At a liquid to solid ratio of 20:1, the conversion of ?free? calcium to carbonates was 75%. A CO2 balance on the system concluded that at the current operating conditions 42% of the total CO2 fed to the system was sequestered in the carbonate form. SEM-EDS analysis of the fly ash particles before and after reaction with CO2 indicated that the carbonate compound being formed was calcium carbonate. The analysis identified rhomboidal structures on the surface of the fly ash particles after reaction with CO2, but not before. These rhomboids are characteristic of calcium carbonate formation and they had higher Ca, C, and O concentrations than the host spheres, suggesting calcium carbonate formation.

Jan 1, 2012

By S McGregor, J Sharp, I Entezari, T Boulter

The piezocone penetration test (CPTu) is one of the primary screening tools used by the mining industry to evaluate whether tailings are susceptible to liquefaction (static or cyclic). Liquefaction analysis using the CPTu is influenced by the fines content of the soil, and most CPT screening tools empirically use the behaviour type index (Ic) to correct for fines. The issue with this approach is that such empirical relationships have been developed using data collected from natural soils and their applicability to different tailings deposits needs to be studied. In this paper, we explore the use of machine learning to develop a site-specific model to estimate fines content of tailings using gamma piezocone penetration testing (GCPTu) measurements. The results are then compared to the fines content derived from the soil behavior type index (Ic) proposed by Robertson and Wride (1998). A dataset of paired GCPTu and laboratory results were compiled and a support vector machine (SVM) algorithm was employed to calibrate a model to estimate tailings fines content from in-situ GCPTu data. We calibrated GCPTu data to geotechnical 75 μm fines content measured in the laboratory. The geotechnical fines content is the fines content as a percentage of solids. The development dataset was comprised of paired GCPTu-laboratory results collected in 2009-2019 from a mining area with predominately clay mineral and quartz sand tailings. Results show that the developed model predicts the geotechnical 75 μm fines content of the studied deposits with 7.8% error. The Ic based method estimates the fines content with 31% error. Evidently, the Ic method is not applicable to the studied tailings deposits. It is appreciated that many tailings fines do not contain clay, and that the success on this program may not be repeatable everywhere. However, the authors wish to point out that the application of site-specific machine learning algorithms may be used to significantly improve empirical geotechnical parameters.

Jul 1, 2021

By Yanli Huang, Qiang Sun, Jixiong Zhang, Yuzhuo Jiang, Dan Ma

Mining accidents due to inrushing water are caused by sudden changes in seepage owing to structural damage to key strata of the aquiclude. The backfill mining method can be used to control the movement of the strata, weaken the evolution of fractures owing to damage by key aquiclude strata (KAS), and control the channel for inrushing water. This study develops a mechanical model of a composite beam on a non-uniform elastic foundation of the KAS by analyzing the coupling relationship between the filling body and the key water-resisting layer of the aquiclude. Equations of the deflection-induced deformation, bending moment, and maximum tensile stress of the KAS are analyzed, formulae to calculate the allowable tensile stress and backfill materials’ compaction ratio (BMCR) to ensure structural stability are derived, and are used to provide the critical BMCR for their structural instability. The results of field measurements show that the subsidence of the roof was 600–700 mm with an average BMCR of 80.63%. Damage to the overlying strata was controlled to ensure safe mining and the disposal of solid waste from the aquifer. The research here is useful for ensuring safety during mining while protecting water resources.

Jul 12, 2022

By Richard J. Finno

Detailed measurements made at a test section adjacent to a deep braced cut and other published data are combined to illustrate the limitations of the common methods of predicting movements associated with excavations in soft to medium clay. While past performance data can be used to estimate expected responses before construction in many cases, actual wall and soil deformations throughout construction can only be estimated using finite element procedures. Success of such analyses depends equally upon considering all aspects of construction that induce strains in adjacent soil, such as wall installation, excavation and bracing sequence, and time, and adequately modeling soil stress-strain behavior. Even when these two criteria are met, soil deformations can not be predicted adequately when strain levels exceed those that produce peak shear stress.

Jan 1, 1991

By Wiliam L. Crentz

The importance of Somerset County, Pa., as a coal producer is due in large measure to the presence reserves of low-volatile bituminous coals. Although many coal beds of minable thickness are present, the important reserves are to be found in those beds underlying the Pittsburgh bed. The Kittenning beds and Freeport beds, which are responsible for the bulk of the present coal production in Somerset County and contain the largest reserves to meet future coal requirements, are usually thin and entirely free from impurities. The Pittsburgh bed, which has been such an important coal deposit in the coal areas immediately west and south of Somerset County, is of secondary importance in this county. Although generally rather friable, Somerset County coals have enjoyed wide receptability as excellent coals and to some extent have been utilized in the metallurgical market.

Jan 1, 1951

By R. D. Saltsman

This report is in fulfillment of Contract No. H023001.5 awarded to Bituminous Coal Research, Inc., on November 15, 1972. The scope of the work under this contract was to perform a two-phase survey for the purpose of determining the status of work in the following specific areas of industry needs under the Technology Transfer Program and to increase industry's awareness of research efforts under the Federal Coal Mine Health and Safety Act of 1969 6f (P.L. 91-173): 1. Research and development of respirable dust sampling instruments which will more accurately collect the respirable Cuss as defined by the Federal Coal Mine Health and Safety Act of 1969. 2. Development of a better means of control of respirable dust and float dust.

Jan 1, 1973

By Steven J. Page

The Bureau of Mines used fiber-laden air to test two identical fibrous aerosol monitors (FAM) in order to establish the FAM-optical count correlation. The FAM is a unique instrument developed by GCA Corp. (GCA) to measure real-time fibrous aerosol concentrations. It will also respond to particulates that have sufficient shape irregularities to possess fiber characteristics such as the 3:1 length: diameter (L:D) aspect ratio. Results of the Bureau's laboratory tests showed that the FAM response is linearly correlated to concentration data obtained using the optical membrane filter count technique approved by the National Institute for Occupational Safety and Health (NIOSH), U.S. Department of Health, Education, and Welfare. A plot of the FAM-optical count correlation showed that FAM concentration readings are generally well within ±25 pct of the optical membrane filter count. Initial tests to estimate the best ratio control setting of the FAM for 5-µm fiber-length discrimination were performed using one instrument only (the ratio control setting determines the minimum threshold fiber length that will be detected by the FAM). The estimated setting was then used to correlate both FAM units. The result was a 65 pct difference in correlation between the two units. It appears that the major factor responsible for this difference was the internal adjustment of the photomultiplier detector sensitivity for each of the two FAM units.

Jan 1, 1980