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By Terry Muldoon

In conventional noncoal, room-and-pillar mining, the cutting machine is frequently a major source of airborne dust. Water is often used for dust control. An evaluation of typically used water systems during this program showed that they reduced dust levels by 60 to 70 percent over dry cutting when at least 0.5 gpm of water was applied. These systems, however, are only marginally effective in maintaining compliance levels and the added moisture causes operational problems. During the program, three additional dust control systems were designed, fabricated, and evaluated. The first, a hollow cutter bar, was designed to capture dust in the kerf at the cutting zone. The system was only marginally effective in reducing dust levels due to its lack of control of other sources. Large quantities of material captured by the system made it operationally questionable. The second, a machine mounted exhaust system, was extremely effective in capturing virtually all the dust generated in the heading. The captured dust was ducted out of the heading and exhausted downstream in the crosscut. Exhausting the dust without scrubbing, however, creates problems for personnel working downstream of the cutting machine. Successful application would require changes to the mine ventilation system and mining sequence. The third, foam, injected foam from an onboard generator through a channel to the cutting zone at the tip of the bar. Test results showed that foam, using 1/3 to 1/2 the total fluid quantity, was equally effective when compared to the mine's current water system.

Jan 1, 1983

By Ralph T. Buscarello

For practical purposes, the terms "natural frequency," "resonance" and "critical speed" are synonymous. A part passing though its "critical" or "critical speed" may also be said to be "resonant" or "resonating." The vibrations of a precisely balanced part can be magnified by the structure in which it is assembled. Anyone who has driven an automobile knows that it will vibrate more at a certain speed than at others. According to the formula for centrifugal force, vibration should increase steadily with a rise in rpm. What happens instead is that the vibration not only in- creases with r m. but suddenly rises at a much higher rate through the critical speed, and then apparently smooths out as the rpm passes beyond it. To visualize what happens, consider a simple flat spring with a weight mounted at one end. When the spring is deflected by pulling down on the weight and then letting it go, the spring will oscillate, and the spring-and-weight system will vibrate at its natural frequency. If the timing or direction bf the impulses imparted to the spring did not coincide with its natural frequency, the result would be an irregular vibration that would not build up. If, on the other hand, the timing and direction of the impulses did coincide with the spring's natural frequency, the result would be a larger and larger amplitude. If the impulses were continued indefinitely, the amplitude of the spring's vibrations would go on rising [while its frequency stayed the same] until the spring broke or the amplitude of the vibrations reached an equilibrium [because frictional or other forces would tend to damp it]. Resonance magnifies the amplitude of vibrations in a relatively undamped system between 100 to 200 times over that of nonresonant vibrations. Frictional or viscous damping often reduces the magnification [from 10 to 20 times], but even with this reduction the amplitude would still be large enough to cause excessive wear, and sometimes even fractures. For example, a blower might show only 0.001 in. of vibration on the manufacturer's test stand. Installed, the blower could pass into its critical speed [the speed at which the frequency of the vibrations caused by the rotor coincides with the supporting structure's natural frequency], and the 0.001 in. of vibration could be resonated to 0.010 in., or as much as 0.020 in. The cure for such a condition would not be to lower the vibration of the blower by further balancing or better alignment but to separate the two frequencies by at least 20 to 30%.

Jan 1, 1970

By A. Azizi, P. Blatter, A. Bouajila

"Due to the high reactivity of sulfide minerals in alkaline cyanide solutions, some parasitic reactions inflict a heavy gold surface passivation and excess cyanide consumption resulting in a dramatic decrease of the gold leaching rate. Atmospheric pre-oxidation was shown to be an effective tool to enhance gold extraction by preventing a passive film from forming on the surface of gold grains. This work aims to highlight efforts undertaken to determine: (1) how gold cyanidation is limited by passivation; (2) what are the reactions and mechanisms involved during gold cyanidation; and (3) how a better understanding of fundamental issues can be used to design a proper pre-oxidation strategy. INTRODUCTION Precious metals (PM), gold in particular, naturally occur in contact within a wide range of sulfide mineral systems. Hence, one of today’s most challenging R&D tasks consists in accounting for the presence of sulfides on the cyanidation behavior of gold. An important body of knowledge reveals that metal sulfides display a range of reactivities in alkaline cyanide solutions (Marsden & House, 2006). Such reactivities are acknowledged to inflict additional utility costs and loss of profits because they are accompanied with higher consumption of cyanide and/or formation of undesirable by-products that are often detrimental to gold leaching rates. Gold recovery in cyanidation is hampered by a multitude of factors, among others: (1) consumption of excess cyanide as a result of the formation of thiocyanate and dissolution of transition (Cu, Fe, Zn, etc.) metals (Habashi, 1967); (2) gold surface passivation by solid reaction products, e.g., Fe(OH)3 (Guo, Deschenes, Pratt, Fulton & Lastra, 2005), sulfur (Dai & Jeffrey, 2006; Jeffrey & Breuer, 2000;) or oxo and thiooxo (SbO33- SbS33-) salts in alkaline solutions (Guo et al., 2005). Because of their energy structure, most of the sulfide minerals exhibit semiconductor properties (Marsden & House, 2006). Therefore, the contact between constitutive sulfide minerals inside complex sulfurous ores entrains electrochemical phenomena in which sulfide dissolution is a genuine corrosion process (Azizi, Petre, Olsen & Larachi, 2010). For instance, galvanic interactions could be initiated between the various constituents within the ore and could substantially increase or decrease the reactivity of some of the associated minerals."

Jan 1, 2012

By William F. Hahn

This project focused effort on three separate areas: demonstration of a low seam longwall illumination system, design of illumination systems for low coal auger miners, and an assessment of machine lighting systems for machinery used to mine low seam coal. Results indicated illumination systems can be purchased by the mine operators of low coal seams. These systems can be supplied with the equipment as a factory integrated system or can be retrofitted to the machine or longwall equipment.

Jan 1, 1982

As land resources decrease, commodity prices increase, and technology evolves, deep sea mining is becoming a viable alternative to meet the increasing demand for minerals. Successful deep sea mining operations are built on sound identification of the resource, proper selection of equipment, a thoughtful production plan, and good project management. These four key activities can be further optimized by analyzing how the spatial variability and uncertainty of the ore body properties impact the final mining operation. To address this problem, IHC Merwede is in the process of developing a risk quantification framework in the context of deep sea mining, which makes use of state of the art geostatistical simulation methods and transfer functions to quantify geological uncertainty and translate it into decision or project risk. The paper introduces the Local Average Subdivision method (LAS) for generating simulated models of the deposit and presents a new extension to incorporate point measurements of geotechnical or ore grade properties. Due to its computational efficiency, the presented method is suitable for simulating largely extended sea floor deposits. The second part of the paper illustrates, through example case studies, the significant benefits of a risk based approach which translates geological uncertainty into financial or operational performance indicators. In particular, the focus is on assessing financial project risk and on the design optimization of the deep sea excavation equipment by analyzing cutting forces, specific energies, and power requirements.

Aug 1, 2013

By C. D. Keith

Erie Mining Company, a pioneer in the iron ore pelletizing industry, has continued to develop methods and equipment to improve cost and quality. Under the management of Pickands Mather & Co., this property, owned by Bethlehem Steel Corporation, Youngstown Sheet and Tube Company, Steel Company of Canada, Ltd., and Interlake, Inc., has initiated a number of operating improvements for the taconite industry. One of the most noteworthy of these, which is applicable to the entire mineral industry, is the principle of fine screening with rappers (FSR). Erie's original efforts in the field of fine screening, which date back to 1961, were described in the April 1967 issue of the MINING ENGINEERING magazine. In that same month, Erie placed into operation a full scale PSR and regrind plant addition, capable of processing 10.3 million long tons of iron ore concentrates, produced by conventional taconite grinding, classification, and magnetic separation methods. Since this first successful commercial operation of the PSR principle et Erie, it has been applied in eight other iron ore beneficiation plants end is being tested by other U.S. and foreign companies. In addition to the use of PSR units at Erie Mining Company, Pickands Mather has applied PSR to other of its managed properties end to projects under development. This paper covers these applications as well as a now application at Erie Mining Company.

Jan 1, 1971

By Earl R. Parker, Ralph Hultgren

DURING the past year publications in physical metallurgy have not been abundant when compared with the output of prewar years. Nevertheless, some noteworthy contributions have been made to the literature. Because of the necessity for war production, much of the metallurgical effort has been directed towards the solution of problems of production processes. The limited amount of time devoted to other problems is reflected in the small number of papers devoted to nonapplied research, though a few excellent contributions have been made to the fundamentals as will become evident in the following pages. Results of many of the government-sponsored research investigations have been released to the public and are being published in the technical journals. Many more of these papers may be expected to appear in the 1946 publications.. Public distribution of information obtained in the course of these investigations should be of great value to American industries in the postwar era. Continued activity in research of all kinds is apparently assured because of intense

Jan 1, 1946

In a previous study, various pyrite depressants were examined to improve the flotation performance of a copper-sulfide ore. Optimal results from this study were used to examine the effect of elevation on recovery and grade. Tests were conducted at elevations of 3350, 1735, 610 and -760 metres, consisted of five repetitive experiments for statistical analysis, and were performed both with and without airflow control. Tests were also performed in a glove box at Montana Tech to mimic the pressure conditions. Results indicate that both recovery and grade are dependent on pressure via bubble size and airflow suggesting that pressurised flotation cells should be considered for operations, particularly those at high elevation. Economics are extremely favourable for implementation because ensuing capital expenses are inconsequential with minimal time for return-on-investment.

Jan 1, 2005

By William L. Husk

Stockpiles have always been a necessary part of coal mining except, perhaps, when a person was mining only for the needs of his family from a seam on his home place or coal mined for the use of a small hamlet and carried to each man's house as it was mined. Then it may have been stockpiled at each man's place for several days or on the village common. Mining with this limited production required waste stockpiling. Stockpiling of the products of coal mining, both coal and waste material, has always been a necessity. Very little coal has ever been moved directly or immediately from the working face to the point of consumption and burned. It has always been expedient to stockpile the coal some- where and store the waste.

Jan 1, 1981

By S. D. D. Welsby

"A pilot-scale flotation column was used to evaluate four polyglycol frothers at Teck’s Highland Valley Copper Mine. The column was fed with flotation plant feed from the grinding circuit cyclone overflow. Frother dosage was changed by controlled addition to the column feed. Pulp, froth and metallurgical performance were assessed using gas dispersion measurements, water recovery and copper, molybdenum and gangue grades and recoveries. Ranking the frothers based on pulp and froth phase performance using gas dispersion measurements and water recovery yielded contradictory rankings. All of the frothers changed the froth structure in a similar manner such that, at the same structural conditions, they all gave the same degree of separation between water and entrained solids. The only difference between the frothers was what dosage was required to achieve a certain structure. Changes in pulp structure appeared to be related to the critical coalescence concentration (CCC) for each frother. Changes in froth structure were not completely described by the CCC and involved other factors, such as the hydrophobicity of particles in the froth. All of the frothers were capable of achieving the same metallurgical result, just at different dosages. Optimal dosages for the frothers were anywhere from the CCC, where copper and molybdenum grades were maximised, to 2 to 3 or 4 to 7 times the CCC, where copper and molybdenum recoveries, respectively, were maximised.INTRODUCTION Background Due to supply issues, Teck’s Highland Valley Copper (HVC) Mine replaced Dowfroth 250C, their auxiliary frother, with Huntsman Polyfroth W31. The primary criterion for selection was that the new frother gave the same performance as Dowfroth 250C, minimising disruption to the circuit. Frothers play a dual role in flotation, altering the bubble size in the pulp zone and the stability of the froth. A stronger or weaker frother, or a blend of both, will alter the balance between pulp and froth effects and, ultimately, metallurgy. Dowfroth 250C and Polyfroth W31 may not necessarily be the best frothers for HVC from a metallurgical standpoint. There may be a different frother or frother blend that could deliver higher recovery in the bulk roughers."

Jan 1, 2014

By H. Murray

Introduction Industrial minerals are key ingredients in a large majority of domestic and industrial products that are used in our daily lives. In the 7th edition of Industrial Minerals and Rocks, fifty three industrial mineral commodities are described. A precise definition of industrial minerals and rocks is difficult. Bates (1975) proposed a definition which is widely used and is as follows: "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the non-metallics". They can be igneous, metamorphic, or sedimentary and range in price from a few dollars per ton to a very high price of hundreds of dollars per ton. The growth in their production and use is closely allied with population growth particularly in countries that maintain a high standard of living. The United States just passed 300 million in population and it is predicted that by 2040 the population will be 400 million. This will result in large increases in the need for Industrial minerals. Other factors that relate to increased use of industrial minerals are increased research and development by the producing companies and better quality control. Many industrial minerals such as kaolin, barite, nepheline syenite, fluorspar, lithium carbonate, phosphate rock, potash, talc, and several others are exported from the producing countries to many users around the world which has significantly increased their use. Also, government agencies, State Geological Surveys, and Universities have contributed to their growth by their research and development activities.

Jan 1, 2007

By Nicholas J. Grant

It is the purpose of this paper to examine a number of the recent developments in powder metallurgy, being most concerned with those which are yet to prove themselves rather than those which have achieved commercial maturity. Such developments include the production of very much coarser and very much finer powders, down to the near-micron size range. Also considered are activated sintering, direct powder rolling and extrusion (both hot and cold), brazing and welding, hydrides of reactive metals, oxide dispersion strengthened alloys and theoretical evaluations. Introduction T HERE surely can't be very much argument with the fact that powder metallurgy has made large advances on many fronts during the past ten or more years (1). These advances have taken place in raw materials, in processing, in product development and in a better understanding of many of the phenomena which occur in the various steps involved in powder metallurgy. It should be clear, in view of such growth, that it will not be possible to highlight all of the new developments in the present paper. Many of these developments,

Jan 1, 1965

By N. Coulson, P. Ledwaba

"The University of the Witwatersrand presents an accredited four-course training programme for community relations practitioners (CRPs). Between May 2013 and October 2014 six courses were facilitated for 145 participants, of whom 82% were from sub-Saharan Africa, 62% worked in mining, and 58% worked directly with communities. Thematic analysis of the comments of course participants collected during course exercises found that there were a set of coherent drivers for resilient companycommunity relationships, but that the restrainers to resilient relationships were often context-specific and dominated by politics. CRPs reported facing as many difficulties in the internal company environment as in the external environment. These findings for CRPs in Africa resonate with those worldwide.InroductionMuch has changed in how the extractive industry responds to social and community issues. There has been a growing prioritization of community-related issues within the extractive industry globally (Kemp, 2010; Tatar, n.d.). According to Kemp (2010) this can be attributed partly to escalating pressure from local-level stakeholders to push mining companies to take greater responsibility for the social, economic, and environmental impacts of mining. Securing and maintaining the social licence to operate is ranked fourth in terms of the top risks facing the mining and metals industry in 2016, up one place from 2015 (Ernst & Young, 2016).Conflicts between local communities and large-scale mining companies arise because of the social, environmental, and economic impacts of mining. Worldwide, large-scale mining companies have a poor reputation amongst communities, including those in Africa (Gilberthorpe and Banks, 2012; Kemp and Owen, 2013a; van Wyk, n.d.). For mining companies, conflicts for whatever reason, result in loss of productivity, lost opportunities, lost time, and adverse impacts on reputation (International Council on Mining and Metals, 2015). Conflicts also have a significant financial impact on mining operations (Franks et al., 2014). Davis and Franks (2014), estimated that US$10 000–50 000 is lost each day when a project is delayed during the exploration phase, and about US$20 million per week when in operation. Today these costs could be expected to be higher due to increasing input costs."

Jan 1, 2017

By A. C. Johnson

This paper is one of a series being prepared by the Bureau of Mines on exploration, development, mining methods and costs at various mines in the United States. It describes such methods at the Lincoln tungsten mine of the Wah Chang Mining Corp., Lincoln County, Nev. The purpose of these reports is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods, practices and costs. The Lincoln mine in Lincoln County, Nev., in the southeastern part of the [tate], was acquired by the Wah Chang Mining Corp., in April 1951. Mining methods and costs are of special interest at this property because of the low costs and good production record achieved through a well planned program of exploration, development, and exploitation. Operations were discontinued in July 1957 after the Federal Government suspended the tungsten purchase program.

Jan 1, 1959

By R. M. Santmyers

Of the sand and miscellaneous silica produced in the United States , ordinary sand and gravel are , of course , the most important, at least as regards volume of output . The building- construction industry absorbs approximately 75 per cent of the total value of all quartz and silica , as shown in Table 2 of Quartz and Silica, Part I, under "General summary . " Because of their unusual physical properties tripoli and diatomite find extremely wide uses in industry, and as the commercial deposits of these ninerals , especially tripoli , are scattered, large quantities enter into interstate commerce . Whereas ordinary sand and gravel are bulky commodities , these specialties have a fairly high unit value and hence can be transported relatively long distances .

Aug 1, 1931

By S. McCalpine, W. Muir, P. J. Downey

"Golden Bear Operating Company Ltd. (GBOC) was a joint venture between Chevron Minerals Ltd. and North American Metals Corp. that was formed for the development of the Golden Bear Project. The mine is located at Muddy Lake, Western British Columbia, approximately 80 km northwest of Telegraph Creek and 135 km west of Dease Lake (see Figure 1). Road access to the mine was developed by Golden Bear and consists of a radio controlled 155 km gravel road originating at highway 114.A feasibility study was completed in 1987 and project approval was finalized in 1988 with Golden Bear issuing a ""Request For Proposal"" for detailed engineering in May 1988. Golden Bear also commenced negotiating with vendors at this time for the supply of the two principal process equipment packages: the dry grinding and classification system and the whole ore roaster package.Process plant engineering and plant construction was completed in October 1989 with plant startup commencing in November 1989. Two months into the commissioning phase it became apparent that the plant, as designed, would not achieve the anticipated production targets.Kilborn Engineering Pacific were subsequently contracted by GBOC to review and modify the plant design, assist the operating personnel with plant commissioning and startup and provide operator training.This Paper describes some of the problems encountered during the startup and the plant modifications incorporated to achieve design parameters."

Jan 1, 1992

By H. R. Butler, R. N. Browne

"The International Nickel Company of Canada Limited consumes some 33 ½ millions of gallons of fresh water and reuses more than 100 millions of gallons of water daily. The continuing search for suitable recycle methodology has enabled the Company to put one 25,000 TPD mill on line utilizing recycled water entirely and a second 35,000 TPD mill is under construction which will likewise employ the concept of recycled water. Future milling plans are aimed at the replacement of all fresh water with recycled water, including sewage effluent and mine waste water.WATER REUSE AT INCO’s SUDBURY MILLSAs man searches unexplored horizons for new and economic industry, he must be constantly and acutely aware of the presence or absence of that precious commodity without which Industry, indeed Man himself, could not survive -- W A T E R. The water requirements of the world today are magnanimous, considering that in 1960 the estimated consumption in the United States was over 300 billion GPD (l) or more than 1,700 GPD per person(5) The magnitude of the problem can be visualized as one considers that three times this quantity of water will be required in the United States by the year 2000, when the dependable supplies of water are estimated to be only two-thirds of that required(2). How, then can we continue to wreak such havoc on that life-sustaining substance - WATER?"

Jan 1, 1970

By J. L. Kohler

Component failures in the electrical control circuits of mining machines account for a large percentage of the total downtime of the machine, Once a failure has occurred it is always a tedious and usually a time-consuming task to locate the failed component. Moreover, the pressure to quickly locate the cause of a delay can lead to compromises in safety. Thus an onboard diagnostic system, essential for an automated machine, would be a very useful addition to existing machines. This report details U.S. Bureau of Mines development of a generic procedure for synthesizing diagnostic systems for electrical-control-circuit failures in mining machinery. A continuous mining machine is used as the testbed to illustrate the application of the developed methodology. Substantive differences among mining machine control circuits made it impossible to achieve a generic diagnostic system, but a generic approach for the synthesis of the diagnostic system was possible. As the research progressed, it became apparent that an algorithmic approach was better than an expert-system-based implementation. A prototype system was constructed and used to evaluate the diagnostic system. Prototype implementation issues are also examined.

Jan 1, 2010

By C. V. Millikan

THE year 1930 in the petroleum industry has been characterized by the establishment of large potential production of crude oil. This has resulted in closer cooperation between companies by proration and unit operation agreements in order to afford an equitable outlet to all, and to prevent a flood of oil being forced on the market with attendant tremendous material and economic waste. Drilling wells in proved areas and wildcat wells are fewer than in the past several years. Restricted production and low prices have caused greater effort to increase producing and recovery efficiencies. Increased refinery efficiencies have amplified the effect of overproduction. Pipe line departments have been especially busy. New oil lines have reached more refineries by new and shorter routes. Establishing greater gas reserves by new fields has justified new gas lines to industrial centers, and has brought this fuel to thousands of new domestic consumers. Two long gasoline lines, a new venture in pipe lines, are being built to obtain a lower cost of transportation and less loss between the refineries and their distribution centers. The chairmen of the various divisions have discussed the developments of their respective branches more fully in the following reviews.

Jan 1, 1931

By FREDERICW K. BRADLE

I HAVE been puzzled by two lines of thought'; one emanating from Washington, D. C., to the effect that we must all cheer up, that in a very short time, measured in terms of months, prices would begin to recover, business would become normal, and prosperity would continue on its way just as before the interruption of a year ago; and a second, coming from certain industrialists and economists, expressing fears that all commodity prices were in for a long downward trend, which would cause much unemployment, eventually drag down wages and so restrict purchasing power as to further aggravate the situation. One basis for the fear of a downward trend in commodity prices' is that ifter great wars a depression could last for something like 40 years-the downward trend to such a depression after our recent World War having been postponed for some reason or other; and the basis for another fear was that the production of gold was becoming less. I had 'also been trying for some time past to refresh my recollection as to how my ow11 particular lead interest climbed out of the depression of 1893; and as all the metals have had, and still have. relative values and prices, I can best express what I have in mind by talking principally about lead.

Jan 1, 1930