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By P G. Bourke, A Yáñez, G J. Jameson, N M. L Kupka

The kinetics of fine and ultrafine particles in conventional mechanical flotation cells are limited (Feng and Aldrich, 1999; Trahar, 1981; Wang et al, 2016). Accordingly, even limited recoveries with such machines require long residence times. Theoretical investigations into the rate of capture of fine particles by flotation, have indicated that a key parameter is the rate of shear in the fluid surrounding the bubbles and the particles. Achieving fast flotation rates of ultrafines requires a new method of bringing the particles and bubbles into contact, utilising the beneficial properties of highly dissipative flows to break through the water boundary layer. In 2010, a new type of flotation cell known as the Concorde Cell was described, in which bubbles and particles are brought together in a sonic shock wave (Jameson, 2010). Earlier research had shown that when a dispersion of fine bubbles in liquid passed through a converging nozzle at the local speed of sound, the resulting shock wave downstream generates a mass of even finer bubbles in the flow as it passes through the shock wave. The fluid within the shock wave is highly turbulent, and an environment is created that is very favourable to particle-bubble collision and capture. In this paper, we briefly describe the Concorde Flotation Cell and give examples of its use.

Aug 24, 2022

By Scott Turner

I have been asked to speak briefly about recent progress in the mining industry of the United States, and to touch on the general advancement of en- gineering science as applied to mining. By recent, I shall mean within the past 20 or 30 years. Such a period includes a great many of the changes which are of particular interest to the present generation of engineers, and the undergraduates of today will hardly turn back farther than the beginning of the present century in their study of develop- ment of methods and processes. Also, my own professional life spans this period, and I have seen or have been aware of most of these developments as they were taking place. In my review of developments, for the sake of simplicity and clarity, I shall deal separately with improvements in metal mining, coal mining, mechanical and electrical machinery for mines, metallurgy, petroleum engineering, and safety practices. Under each of these headings I have set down what appear to me to be the outstanding changes brought about during the past 2 or 3 decades. Other points will occur to other engineers; I do not represent that the following re- view is complete; it is only intended to be suggestive. In general, improvements in mining and metallurgical practices have come gradually, the charges being effected little by little, simultaneously in widely scattered places, and through the experience and inventive genius of many men. These changes have has small beginnings, and are generally the cumulative result of many steady and unsensational progressions, which still continue. What we today might be inclined to consider the culmination of a series of betterments in mining is, of course, but an instantaneous phase of developments which will continue in the future at even a more rapid pace than they have in the past. We are looking at but a flesh of a moving picture, with an endless reel to come after we finally leave the theatre. Behind all the changes in the mineral industry, the driving force has been the increasing demand of an expanding population for more metals and minerals with which to advance civilization. More people, with an increasing per capita consumption, together with the exhaustion of the richer but smaller, and more

Oct 1, 1930

By F. J. Chernosky

Most previous studies of coal flotation utilized chemically pure reagents. Since such reagents are not available in quantity, a study of various wmmercially available reagents as frothers was undertaken. Flotation procedures similar to those used in a large number of commercial coal flotation plants were employed. The reagents used were compared on yield-selectivity-wst basis. The selectivity was found to be relatively constant with yields above 70% but the reagent cost varied greatly. The types of reagents available were compared. In the past, a number of papers have been written on the use of various reagents as coal flotation frothers. For the most part, these have been an attempt to correlate the intrinsic chemical and physical proper- ties of the reagents or reagent groups to the floata-bility of various fine coals. Because of the type or nature of evaluations made, chemically pure reagents were normally used. Generally, these reagents are unavailable in commercial quantities. Therefore, the results obtained with these reagents were usually limited in usefulness to the plant operator or metallurgist. This paper presents the results of a study in which commercially available forms of various reagents were used as flotation frothers. Flotation procedures which would conform in general to those employed in a large number of commercial coal flotation plants were utilized. The objective of the test was to compare these reagents on yield-selectivity-cost basis, that is, 1) the yields obtained, 2) the ash levels obtained and 3) the reagent cost relating to these results. REAGENTS The reagents employed have been grouped into the following chemical classes: 1) aliphatic alcohols, 2) terpines, 3) glycols (synthetic water-soluble

Jan 1, 1963

By Tadashi Aiura, Yasuhiro Miura

"A small amount(0.2mass%) of Scandium(Sc) was added to the 7.NOl and 5083 Al alloys as a refiner and stabilizer of microstructure, and the resulting microstructures were discussed in comparison with the effects of the conventional additives. The followings are summarized: 1) in the as-solidified structure, a ·decreased tendency of constitutional supercooling and increased solubility of Mg were recognized for the Sc-added 5083 alloy. Sc is a -better microstructure refiner for the 7N01 alloy than Zr, in a sense that it does not suppress the favorable effect of· coexisting Ti. 2) Sc effectively suppresses recrystallization both in the 5083 and 7N01 alloys. 3) The rod like primary Al3Sc crystals formed during solidification, as well as the fine dispersion of Al3Sc precipitates formed by subsequent heat treatment, can act as a strong recrystallization suppresser. IntroductionThe 7N01 and 5083 alloys are the most popular industrial Al alloys and they are widely' used for various structures because of their superior properties. Fine macro and micro structures of the materials are required for obtaining acceptable sec resistance,consistent appearance of anodized surface and good weldability, as well as good mechanical properties. In order to produce fine grain structures, transition metals, such as Cr, Zr, and Mn, have been conventionally added.It has been reported that Sc is an efficient refiner [l, 2] and can be an alternative for the conventional and also suppresses recrystallization in Al alloys [3,4]. Scandium is the lightest transition element and forms an equilibrium intermetallic phase. The equilibrium phase, Ll2-Al3Sc, is coherent with the matrix, and of _spherical shape. A fine dispersion of the spherical precipitates is obtained by quenching and aging after solutionizing annealing. The authors have already reported a part of the experimental results on the effect of Sc on the as homogenized microstructure of the 5083 alloy [5]. In the present study, the effects of Sc on the macro and micro structures of the industrial high strength Al alloys(7N01 and 5083) for extrusion are investigated, and the superior role of Sc as a grain refiner is shown"

Jan 1, 2000

By Linn Bradley, W. W. Strong, H. D. Egbert

A hot-dry method of cleaning the gas from blast furnaces has been shown1 to conserve the sensible heat energy of the gas, and in general it thus permits of a higher flame temperature. The electrical method of cleaning gases removes from 98 to 99 per cent. of the suspended matter in one operation when operating properly, thus making possible the use of a very clean gas for burning in the stoves. The use of such clean gas thus makes feasible a different type of hot-blast stove construction from that being used at present. It therefore seems advisable to construct the stoves from the viewpoint of getting the maximum amount of heat energy into the products of combustion. By preheating the air added to the top gas and obtaining a better mixture of the air and top gas, less excess air will be required and a higher flame temperature obtained from the combustion of the top gas. The interior of the stove should be provided with a kind of brick that will withstand a high flame temperature, will conduct the heat energy along certain directions, insulate the flow of heat along other directions and at the same time store heat energy so as to make the flow of such energy more uniform. It is quite likely that these results can be best obtained by using several kinds of bricks: one type which is a good insulator of heat energy to be used for lining the stove and for making partitions through the stove to restrain the flow of heat; another type of brick or material with high refractory qualities; and a third type which will be a good conductor of heat energy. The surface of the stove exposed to the atmosphere should be a minimum in comparison to the mass of checkerwork which it is possible to obtain, due regard being paid to other conditions. With clean and hot furnace top gas it will be advisable to consider a rearrangement of the checker work in the stoves. One season for the present size and shape of checker openings is to provide facility for

Jan 1, 1917

By Phillip R. Moyle

In 1985 the U.S. Bureau of Mines evaluated the mineral resources of tie Bruneau River and Jarbidge River study areas, Owyhee County, ID, for the U.S. Bureau of Land Management. The study areas, separated by a narrow corridor, include 90,000 acres of the 107,020-acre Bruneau River Wilderness Study Area (ID-111-17) and 47,000 acres of the 75,340-acre Jarbidge River Wilderness Study Area (ID-17-11). They lie 26 miles and 55 miles, respectively, due south of Mountain Home, ID. Approximately 38 placer claims for gold and 182 lode and placer claims for jasper, agate, and limestone were located within and adjacent to the study areas from 1893 to 1981. Currently, there are eight mining claims for jasper at Indian Hot Springs along the corridor between the study areas.

Jan 1, 1987

By Antonio Fabiano de Oliveira

The aim of the present research work is to study the influence of hard chrome covered skin pass cold rolling rolls using 2D/3D surface topography, i.e. roughness characterization. The common stochastic structure Shot Blast Texturing (SBT) does not meet all requirements related to the production line regards to the finished product. The Hard Chrome layer, applied on these SBT rolls, can improve the sheet surface quality and is of fundamental interest mainly for those steel mills that do not have another alternative to new surface structures such as those that may be provided by the EDT, LT, EBT, etc. methods. The function of the generated surfaces, obtained by these different methods is going to influence the tribological properties during the subsequent forming processes. On the other hand, they can increase the product final cost or require large investments to obtain such surfaces. The results here presented are in accordance with other recently published research work, showing that there is a relationship between these parameters, and that further detailed studies are needed.

Aug 17, 2017

The 30th annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Star Pass Resort, Tucson, AZ on Saturday, Dec. 1, 2012. Each year, one living inductee, two recipients of Medals of Merit and up to five honorees from mining history are chosen by the MFSW for their outstanding contributions to the mining industry. Gregory H. Boyce will be the guest of honor, featured speaker and inductee into the American Mining Hall of Fame. Boyce, chairman and chief executive office of Peabody Energy, is being honored for his leadership in the coal industry.

Jan 1, 2012

By James K. Hallenburg

Geophysical borehole logging is a valuable and inexpensive tool for coal deposit evaluation, development, and production. In addition to the usual determinations of depth and seam thickness, geophysical borehole logs can effectively and accurately determine the coal ash, moisture, and heat contents in situ. Location and evaluation of the partings can be done quickly and accurately. Overburden character determination, such as roof competence, dewatering parameters, ripability, trace element content of the coal and overburden, and sulfur content can be done with existing tools and techniques. The quality of such determinations depends upon the quality of planning and calibration.

Jan 1, 1984

By J. Phillip Mackey

A whole new group of non-ferrous pyrometallurgical processes with the ability to utilize tonnage oxygen and capture sulphur dioxide were developed and commercialized over the period 1940s–1980s. Many of these earlier process developments were undertaken with limited knowledge of the process chemistry and influence of key process variables; in many cases, piloting helped provide much new physico-chemical data, but gaps remained. The second generation versions of these technologies of today provide all the primary copper, nickel and lead produced worldwide by pyro-metallurgical smelting. Further, process development has continued and a new generation of copper and lead smelting technologies have also been developed in China since the 1990s. The older reverberatory and blast furnaces have been progressively replaced by the newer technologies—a good example being the introduction in 1992 of the copper IsaSmelt technology at the Mt. Isa smelter in Australia where the former fluid bed roaster and reverberatory furnaces were replaced by a single new smelting unit, together with an acid plant for sulphur dioxide collection. The development of these new technologies was made possible by investment in fundamental and applied research. The lesson for the future is, in order to sustain these improvements, continued investment in research and development capability is required—to do otherwise is to risk obsolescence and lack of competiveness in the world market. Dr. Peter Hayes at The University of Queensland is one of the many researchers and process engineers who have contributed to the fundamental understanding of metallurgical processes over this period of rapid change in technologies. The present paper briefly outlines some of the many contributions Peter Hayes has made to the understanding of kinetics, mechanisms and phase equilibria in metallurgical systems, and metallurgical process development.

By F. C. Appleyard

A couple of miles southwest of the town of Saltville in the western tip of Virginia is a little village called Plasterco. Gypsum has been produced in this area since about the year 1815, being originally found as small outcrops at the surface. Production in the early days was very small, and the use of the mineral was limited to that of "land plaster" or ground gypsum which was spread on the land to sweeten the soil. In the late 1800's, a small calcining plant was constructed and the production of gypsum plaster began. About this same time, the surface rock was depleted and it became necessary to begin underground mining operations in order to maintain a continuous supply of raw material. The United States Gypsum Company became interested in this property in 1909, and has operated there ever since, having enlarged the calcining mill and built a plant for the manufacture of gypsum wall-board in the middle 1920's. Production of gypsum continues from underground' mining operations, and the present mine at Plasterco is now about 1,000 feet below the surface, making it the deepest gypsum mine' in the world.

Jan 1, 1965

"Butte originated as a placer mining camp. The first gold discovery was made in the year 1864, near what is now Main Street. Placer mining was vigorously prosecuted along Silver Bow Creek and in Missoula, Buffalo, Town and Parrot gulches for a period of five years, at the end of which time, in 1870, the camp was practically deserted. In the meantime, the quartz veins so prominently traceable over the hillsides were located, the first location being made by W. L. Farlin and called the Black Chief claim, and later restaked as the Travona. Reasoning from the presence of the gold placers, free-milling gold ores were eagerly looked for by the early prospectors. Claims covering the great Rainbow and other silver lodes were located in the sixties. The presence of valuable silver ores in these veins caused the staking out of many claims, believed to be valuable only for silver, but which later proved to be enormous copper producers.Treatment of these early discovered rich ores was first attempted in arrastres. Later, stamp mills were built. The Centennial dropping 10 stamps, was the first, and in 1875 Mr. Farlin built the Dexter 10-stamp mill, intro¬ducing chloridizing-roasting. More successful processes were soon introduced and several large mills built, among which were the Alice, Lexington, Silver Bow, Moulton and Bluebird, in all representing a total of 290 stamps. The silver mining industry reached its zenith in 1887 and declined rapidly in the early nineties, following the sudden drop in the price of silver in 1892.During this period of silver mining activity the business of copper mining was making rapid strides. Development of the veins, located as silver veins, had uncovered copper ore in many instances. There was great activity in ""claim staking'' in the years from 1871 to 1879, during which period most of the claims covering the present productive copper area were located."

Jan 1, 1913

By P. J. Mackey

A whole new group of non-ferrous pyrometallurgical processes with the ability to utilize tonnage oxygen and capture sulphur dioxide were developed and commercialized over the period 1940s–1980s. Many of these earlier process developments were undertaken with limited knowledge of the process chemistry and influence of key process variables; in many cases, piloting helped provide much new physico-chemical data, but gaps remained. The second generation versions of these technologies of today provide all the primary copper, nickel and lead produced worldwide by pyro-metallurgical smelting. Further, process development has continued and a new generation of copper and lead smelting technologies have also been developed in China since the 1990s. The older reverberatory and blast furnaces have been progressively replaced by the newer technologies—a good example being the introduction in 1992 of the copper IsaSmelt technology at the Mt. Isa smelter in Australia where the former fluid bed roaster and reverberatory furnaces were replaced by a single new smelting unit, together with an acid plant for sulphur dioxide collection. The development of these new technologies was made possible by investment in fundamental and applied research. The lesson for the future is, in order to sustain these improvements, continued investment in research and development capability is required—to do otherwise is to risk obsolescence and lack of competiveness in the world market. Dr. Peter Hayes at The University of Queensland is one of the many researchers and process engineers who have contributed to the fundamental understanding of metallurgical processes over this period of rapid change in technologies. The present paper briefly outlines some of the many contributions Peter Hayes has made to the understanding of kinetics, mechanisms and phase equilibria in metallurgical systems, and metallurgical process development.

By T Barnes, K D. Sexton, T J. Tope

For the past decade, the U.S. Department of Defense (DoD) has been under increasing pressure from state and federal regulatory authorities to develop management strategies for waste streams generated at its bases, installations, and ranges. Since passage of the Federal Facilities Compliance Act (FFCA) in 1992, concerns have focused in particular on military munitions and energetic waste streams.

Jan 1, 1997

By Sidney Katell

This report is the fourth in the series, Bibliography of Investment and Operating Costs for Chemical and Petroleum Plants. The initial work, Bureau of Mines In- formation Circular 7516, was published in October 1949 in conjunction with the synthetic liquid fuels program authorized by Public Law 290, 78th Congress. It included references to and abstracts of publications appearing from 1930 to September 1948 on all processes in general use in the petroleum refining and chemical industries. A supplemental bibliography, Bureau of Mines Information Circular 7705, was published in January 1955 to cover the period September 1948 through June 1952; and Supplement 2, Information Circular 7751, published in September 1956, covered the period June 1952 through June 1954. The present supplement covers the period July 1954 through December 1956.21 The information in this paper was obtained from the following sources: 1. Bureau of Mines Information Circulars. 2. Bureau of Mines Reports of Investigations. 3. Chemical Engineering. 4. Chemical Engineering Progress. 5. Chemical Engineering Costs Quarterly (Cost Engineering).

Jan 1, 1958

By H. H. Gardner

INTRODUCTION THE problem of mechanization is one of the most vital in the minds of Alberta coal operators today. In these times of constantly increasing operating costs, any way of decreasing the cost of a ton of coal must be explored to the limit. There seems no better field for such effort than the successful application of power to the mining and loading of coal. We are fortunate in having neighbours to the south who have made .remarkable progress in recent times along these lines. Higher tonnages per man have resulted in higher wages to the employee and lower cost to the employer. It might seem that our problems could be solved merely by imitating our neighbours. Unfortunately, neither practice nor experience substantiate this conclusion. It is with the purpose of reviewing our accomplishments, as compared with practice in the United States, and at the request of the Prgoramme Committee for this meeting, that this paper is written. The Committee believes that such a general discussion and comparison may well lead to further advances in our mining methods. SUMMARY OF PRACTICE IN THE UNITED STATES A visit to the highly mechanized coal mines of the United States is always most instructive and encouraging.

Jan 1, 1951

By Carlos Torres, Albert Cabrejo

For the last 20 years mine slopes have been monitored with slope stability radars. Since 2015 a group of dedicated geotechnical engineers dedicated to remotely monitor radars around the world have detected 2000+ slope failures of different characteristics. A statistical analysis of the information gathered of these failures have been made and the summarized results are presented with some degree of analysis appropriate for the vastness of the database. The analysis considers different types of commodities, countries, mining processes, rock types, and weather conditions.

Sep 29, 2023

By K L. C Gontalves

In 1999, the Mineral Development Centre of CVRD (CDM) acquired a flotation device referred to as Mini Pilot Plant (MPP), which is able to run continuous flotation tests with drill core samples. Since then this equipment has been used to define the flotation circuit and process conditions during the pre-feasibility phase of CVRDÆs copper sulfide projects. Until now, the MPP results had not been validated for an industrial flotation operation. The present work consists of a comparison and correlation of the results from a flotation MPP and an industrial plant. In order to make this comparison, an industrial plant was completely sampled and the feed ore was tested on bench scale and on a MPP. The metallurgical and mass balances of each test were used for the comparison.

Jan 1, 2005

By Jim Richards, Eli Choueiry, Brett Robinson, Amanda Elioff

The Los Angeles Metro Gold Line Eastside Extension (MGLEE) extends Metro’s light rail system to the densely populated and growing East Los Angeles communities. Much of the 6 mile alignment consists of at-grade track, but the project also features a1.7 mile underground segment in cut-and-cover and twin-bored tunnel structures. In light of past experiences with open shield construction, The Metropolitan Transportation Authority (Metro) specified, for the first time, use of Pressure Face Tunnel Boring Machines (TBM’s) to advance tunnels through soft ground. This paper describes the history of the tunnel design, construction management, and construction methods adopted that resulted in successfully completing the tunneling segment.

Jan 1, 2007

By P. T. L. Koh

The effect of particle shape on the flotation process has been investigated in laboratory experiments with monosized spherical ballotini and roughly ground ballotini. The particles were treated by partial methylation with trimethylchlorosilane to achieve varying degrees of hydrophobicity. In flotation, the process of film thinning and liquid drainage is critical in the formation of a stable bubble-particle attachment and this is affected by the particle shape and surface hydrophobicity. The rate of attachment affects the overall flotation rate. Flotation tests with different particle sizes at various degrees of partial methylation have been performed in a modified Denver cell. Predictions from a computational fluid dynamic model of the cell which incorporates fundamental aspects of bubble-particle attachment are compared against flotation test results. Contact angles of the particles have also been measured using the capillary rise technique to indicate surface hydrophobicity.

Jan 1, 2014