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By E. A. Holbrook

IN my thirty years of educational work in the mineral industries and other engineering fields, this past year has been the most unusual and difficult one. Contact with educators from other schools leads to the conclusion that the same situation is countrywide. The first of our difficulties came from the shortsighted policy of the Selective Service in taking out of the colleges, continuously, all engineering students as soon as they had reached their eighteenth birthday. England, Canada, and Russia, too, even in the midst of their critical war situations, had the good sense to keep their young engineering brains in college, for they realized the vital necessity of a steady flow of engineering graduates into the war industries and into the postwar peace industries. As a result of the policy of our Government, our engineering schools were left with only a handful of students who had been rejected for military service. Our colleges, faced with the prospect of several years without students and without income, hastened to give leave of absence to many of their competent teachers who quickly were taken into industry and in many instances are now being retained there at higher salaries than colleges are accustomed or able to pay their teaching personnel. We are finding it most difficult to induce these men to return to their former engineering teaching work. In my judgment, it will take us three or four years to restore our engineering departments to their former level in quality of instruction.

Jan 1, 1946

By Michel C. Frippel

This section of the Minerals Yearbook reviews the minerals industries of 45 countries: the 12 nations of the European Community (EC) (Belgium, Denmark/ Greenland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, and the United Kingdom); 6 of the 7 nations of the European Free Trade Association (EFTA) (Austria, Finland, Iceland, Norway, Switzerland, and Sweden); Malta; the 11 Eastern European economies in transition (Albania, Bosnia and Hercegovina, Bulgaria, Croatia, Czechoslovakia, Hungary, Macedonia, Poland, Romania, Serbia and Montenegro, and Slovenia); and the countries of Central Eurasia (Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgystan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan).

Jan 1, 1994

By Roger V. Pierce

"WITHOUT mineral wealth, modern man would not exist. True, man could survive on a stone-age basis with an average life expectancy of, say, 25 to 30 years -once he got past infancy.However, no metal would tip his arrow in a hunt for protein; no steel plough would break the soil for the organized planting of seed; and no coal, nor oil, nor natural gas nor uranium fuels would pro-vide him with light or beat or safety from either beasts, or other men, or an unkind nature that threatened him and his family.Modern agriculture, fishing and forestry represent the other three wealth-producing industries. With-out metals, non-metallics and energy minerals, however, it would be impossible to fit any of these to man's modern needs."

Jan 1, 1967

By Hillary W. St. Clair

Mining activity began in colonial times with ironmaking operations scattered along the eastern seaboard. Iron furnaces and forges manufactured iron implements from bog iron ores using charcoal from the extensive forests as a fuel. Lead ores were mined in the Mississippi Valley and copper ores in the Lake Superior region. However, the real beginning of the American mining industry did not occur until the 19th century. The history of American mining is organized around three epochal events. The first was the discovery of gold in California in 1848, which marked the beginning of a period of apprenticeship in mining and metallurgical techniques. The second was the discovery of the fabulous Comstock Lode in western Nevada in 1859, which expanded mining throughout the Far West and led to large-scale underground mining and the development of smelting techniques for lead, silver, and copper ores. The third event was the building of a transcontinental rail-road system after the Civil War, which brought about the consolidation of the industry from a large number of independent mines, mills, and smelters into integrated operations run by large corporations. Thus developed the mining industry that today supplies the energy and critical materials for the great-est industrial complex the world has known.

Jan 1, 1977

In this issue, the Bureau of Mines announces the availability of the latest of its Mineral Perspectives series: ?MP-4, mineral Industry of Western Europe." This publication describes the mineral industries of 19 Western European countries. For readers unfamiliar with this new series, reproduced below and on the two succeeding pages, is the section dealing with the mineral industries of France. Information regarding acquisition of this publication is found inside the back cover of this issue. FRANCE France is a moderately important producer of minerals, including iron ore, coal, potash, fluorspar, and uranium. In addition, France is a significant processor of imported minerals, chiefly for its own consumption. In general, it has exportable surpluses only of a little iron ore (low-grade ore exported to Luxembourg) and some nonmetallics.

Jan 1, 1977

By A. M. Gaudin

In the first place, let me thank you for inviting me to appear before you today to speak to you on "Mineral Industry Problems - Present and Future". It is a distinguished honor for me to have this opportunity, and I am highly appreciative of this distinction. The beautiful surroundings of Gatlinburg and the pleasantness of a summer occasion are a wonderful tonic for all of us, yet they should not blind us to the seriousness of our Industry's problems No doubt, because of my past appearances before members of the Society of Mining Engineers, at which I discussed wholly scientific topics, or research in the Applied Sciences, you may be expecting me to revert to these subjects. But I intend to venture in a field that is new to me, yet old to all of us, the field of Economics.

Jan 1, 1962

By Kenneth Maas

The Bureau of Mines devoted portions of the 1987-1988 field seasons to investigate the mineral aggregate industry in Juneau, Skagway, Haines, and Gustavus, Alaska, as part of the Juneau Mining District study. Statistics compiled for current suppliers include location, activity, reserve estimates, expected mine life, and types of commodities available. Each population center, except for Gustavus, is well endowed with suitable mineral aggregate to last at least 20 years. The Bureau of Mines quantified the mineral aggregate resource in many large potential sites within each area. Sampling, engineering and soil-index testing, site descriptions, deposit dimensions, and gold recovery information is described. Refraction seismic studies performed at three localities revealed gravel thicknesses in excess of 40 to 80 feet. In the Juneau area the Herbert/Eagle Rivers outwash area, East Fork Lace River. Antler/Gilkey Rivers, and Grizzly Bar (Taku Inlet) individually contain in excess of 60 million yd3 of excellent-quality aggregate with minor accessory gold credits. Haines is also well endowed with aggregate resources; large, quality deposits occur along and at the confluences of the Chilkat, Katzehin, Klehini, Tsirku, and Kicking Horse Rivers. Large deposits of granitic aggregate exist in the Skagway River and East Fork Skagway River.

Jan 1, 2012

By Rodrigo Fina Ferreira

This paper presents a mineral liberation study on two iron ore samples from the Quadrilátero Ferrífero, in Brazil: compact itabirite of low-grade metamorphism (CI) and friable itabirite of high-grade metamorphism (FI). The quartz liberation spectrum for both samples have been obtained through QEMSCAN analyses, carried out for several comminution degrees, to compare the liberation characteristics and to evaluate the evolution of the quartz’s liberation degree after fragmentation. The results have shown significant differences in liberation spectrum between the itabirite samples studied. The liberation process of FI was easier than of CI, due its high porosity and larger crystal size compared with CI, which has shown more complex mineral assemblages with low porosity and smaller crystals. The quartz liberation spectrum has shown that grinding at P95 of 0.210 mm for the FI sample, and of 0.045 mm for CI sample, should result in satisfactory liberation for subsequent concentration step.

Aug 1, 2018

By Pina P, Pereira MJ

The increasing exhaustion of raw materials entails the exploitation of poorer orebodies where the target mineral occurs frequently in a very fine dissemination. Consequently it is necessary to grind more and more fine to achieve an adequate mineral liberation. In other words, it is of fundamental importance to know what size one should grind in order to avoid the following detrimental situations: 1. Excessive grinding - giving rise to the generation of ultra-fine slime particles which may be lost in the ulterior concentration process and simultaneously leading to higher energy consumption. 2. Incomplete grinding - giving rise to insufficient liberation and consequently leading to considerable losses of the valuable components in the tailings. Although this issue constitutes one of the most important steps in mineral processing, little research has been done compared to other processes, mainly due to the fastidious experimental work required. This paper describes a complete and integrated system of image analysis, where some algorithms to determine automatically the degree of li beration, for different levels of grinding, are proposed. These algorithms, mainly based on mathematical morphology theory were tested with images obtained from polished sections of different grain size fractions. Cases studies on a complex sulphide ore from an important copper and tin deposit located in the South of Portugal are discussed. Samples of the unbroken ore are also studied by image analysis to predict the degree of liberation obtained according to the fineness of grinding.

Jan 1, 1993

By J Addai-Mensah, W Skinner, C Kelsey, J R. Kelly, E Baawuah

Comminution continues to be the most capital-intensive unit operation in mineral processing. The fundamental purpose of comminution is to liberate the valuable minerals so that they can be economically concentrated into saleable products. Declining ore quality characterised by lower grade and increased complexity requires significant energy consumption for comminution. Low-grade magnetite ores are typically fine-grained and require fine to ultra-fine grinding (P80 ~ 30 - 40 µm) to enhance its liberation from the typically siliceous gangue matrix. Historically, this has been achieved using multi-stage crushing and grinding technologies, which require high energy consumption with low energy efficiency. This motivated innovations in energy efficient technologies for comminution. Such technology has been developed in the IMPTEC super-fine crusher. It is an innovative, dry (with the potential to be operated wet), media-free, energy efficient crusher that can to reduce 10 mm feed particles to 19 – 30 µm with very low recycle loads. In this study, the mineralogical and physicochemical characteristics of crushed magnetite ore using the IMPTEC super-fine crusher have been investigated in comparison with those of rod milling. The super-fine crusher generated higher liberated magnetite minerals in the – 300 + 212 µm and < 45 µm size fractions compared to rod mill. Both comminution devices generated large low-grade hematite and goethite middlings. However, the rod mill produced higher locked/unliberated hematite and goethite compared to that of the super-fine crusher. Quartz mineral had the highest liberation irrespective of the comminution device used. The super-fine crusher generated higher entrapment of other minerals within the silica matrix compared to the rod mill. The breakage mechanism of the super-fine crusher which is predominantly through high compression with shear, generated improved mineral liberation in the coarse size fractions compared to the predominant abrasion and attrition breakage mechanisms of rod milling. The higher mineral liberation generated by the rod mill is potentially due to the prolonged batch milling of the ore compared to the single-pass open circuit of the super-fine crusher.CITATION:Baawuah, E, Kelsey, C, Kelly, J R, Addai-Mensah, J and Skinner, W, 2018. Mineral liberation studies of IMPTEC super-fine crusher – 130 crushed product, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 313–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By JOHN R. SUMAN

IT appears now that the conflict with the totalitarian states will be a long-drawn-out struggle. The course of this war up to now indicates that this may well be the first major conflict where man power has not been the vital and determining factor. Mechanized warfare has made it possible for relatively small, well-equipped groups to outmaneuver and defeat large armies which lack the necessary modern equipment. Under these circumstances, ultimate victory becomes a matter of resources and productive ability. The important question is not how many soldiers can he put into the field, but the volume and speed in producing the armaments essential to ensure a victory. The resources available to the opposing nations and the efficiency of their systems of enterprise and production will be primary factors in determining the ultimate outcome. Germany had a head start of eight years in the armament race, and it is not easy to overcome such an advantage overnight.

Jan 1, 1942

By J. Groff

The Getchell and Twin Creeks mines are located along a north-northeast trending structural zone in Humboldt county, Nevada approximately 40 miles northeast of the town of Winnemucca. Gold mineralization at the Getchell mine is represented principally by sulfide-rich ores, which contain significant amounts of realgar and\ orpiment, with the gold being recovered through processes which involve pressure oxidation. In contrast, oxide ores are currently being mined and processed at the Twin Creeks mine although large reserves of sulfide ores, some of which contain orpiment-realgar-stibnite, have been defined (Bloomstein et al., 1990). The Getchell and Twin Creeks mines represent major gold orebodies but very little has been published pertaining to mineral paragenesis and the characteristics of ore-forming fluids for these deposits.

Jan 1, 1994

By L. A. Neumeier

The Bureau of Mines, U.S. Department of the Interior, is investigating the feasibility of partitioning complex sulfide minerals to simpler sulfide .phases by sulfldation reactions. Such partitioning can afford opportunity to improve selective extraction of mineral constituents of value. This report describes initial research involving sulfidation partitioning of chalcopyrite concentrates. Small chalcopyrite samples were sulfidized with elemental sulfur in glass capsules sealed after evacuating and backfilling with helium, by heating for 1 to 24 h at specific temperatures in the range of 250° to 500° C. which extends from below to above the boiling point of sulfur (-445° C). Above the boiling point of sulfur, the overall reaction with adequate sulfur (13.9 wt pct of CuFeS2) is 5CuFeS2 + 4S g ? Cu5FeS6 + 4FeS2.

Jan 1, 1989

By L. O. Thomas

THE Alaska Highway, in its course through British Columbia, traverses parts of two great physiographic divisions of Canada which are also distinctive geologically-the Cordillera in the western section and the Interior Plains in the eastern. The Cordilleran region in the portion of the Province with which this paper deals can be divided into four major northwest systems, known respectively from west to east as Coastal, Plateau, Cassiar-Omineca, and Rocky Mountains. The Coastal system consists solely of the Coast range except in the extreme northwest, where a part of the St. Elias range is included. The Coast range, characterized by mountains of great ruggedness,. is made up of an igneous complex of granitic rocks intruded chiefly as a great batholith. In places, spurs of these rocks extend into the Plateau heft, a partly mountainous tract largely occupied by quartzites, quartzose mica schists and their gneissic phases, and crystalline limestone with interbands and broad areas of chlorite, _hornblende, and sericite schists and bodies of intrusive granite gneiss-an assemblage of rocks known as the Yukon group. The Cassiar-Omineca system marks the divide between the Pacific and Arctic drainages. Its eastern boundary is well defined in the south by the Rocky Mountain Trench (see p. 229). The rocks of the system are, miainly, highly altered Palaeozoic sediments, but there are also Precambrian and Mesozoic rocks, the latter largely volcanic. The core of the system is granitic and there is evidence (see p. 221) to support the belief that it is of such a length as to constitute a batholith comparable to that of the Coastal system.

Jan 1, 1944

By A. W. Jolliffee

ANY attempt to forecast the mineral resources of a largely unknown region is hazardous and, in the case of the Northwest Territories, such a task is even more hazardous than usual. This is not merely because of the immense territory involved (over a million and a quarter square miles), only a small fraction of which has ever been explored or prospected, but also be-cause both the geology and mineral deposits thus far examined show many unique features, and, finally, because the region is being actively prospected at the present time. However, in view of the present widespread interest in Canada's mineral resources, a brief compilation of what is known regarding mineral occurrences and geology in the explored parts of the far north seems timely. From these assembled data, a few inferences are warranted as to future mineral production from this region. HISTORY The story of mineral discovery in the Canadian northwest is a fascinating one. As well, it abundantly illustrates the importance of mineral occurrences in indicating future mining possibilities. The same sequence of events has repeated itself too often to be merely fortuitous.? In most cases, the dis-covery of a mineral deposit of possible economic value has been foreshadowed by the finding of the valuable mineral or an associated mineral in the same district, generally in small quantity, by an early explorer or traveller. Thus, John Franklin reported oil seepages from the base of Bear Rock, near Nor-man, at almost the very spot where oil was struck nearly one hundred years later. Again, some would-be Klondikers, deterred by the hardships of the route, remained to prospect around Great Slave lake, and were the first to report the Pine Point lead-zinc occurrences there and the gold-bearing veins on Yellowknife bay. Sporadic prospecting followed at the latter locality for over thirty years before the recent rich strikes were made. Similarly, in 1847, Dr. John Rae picked up a boulder of copper ore south of Rankin inlet, on Hudson bay. More than eighty years later, a body of copper-nickel sulphides carrying values in platinum metals was found at this locality. Also, the report of cobalt bloom on the east coast of Great Bear lake brought back by a Geological Survey of Canada party in 1900 was a factor in the events leading to the discovery of silver and radium there in 1930.

Jan 1, 1937

By Aaro E. Aho

Yukon, one of the most potentially accessible, relatively undeveloped, regions of Canada, has major mineral possibilities. The Klondike placer gold fields and the Mayo silver-lead ?district are the sole major producers but large base-metal re-serves have been discovered in re-cent years and important asbestos deposits are now being explored. Several major exploration companies are active in this region despite short seasons, permafrost overburden, remoteness, lack of transportation, and resultant high costs. Pro-posed new roads can be expected to accelerate development. At ?present the major future mineral possibilities are considered to be lead-zinc, copper, aslbestos, silver-lead, gold, and mineral fuels. These and other mineral possibilities are outlined for various geological subdivisions of Yukon. Major favourable metallogenic features of Yukon include complexity of rock types and structures, widening of the Cordillera with cross-trends, and variety and quantity of mineralization found even with limited prospecting. Comparisons with southern 'British Columbia and the U.S. Cordillera suggest that further exploration will result in discovery and development of more major ore deposits and reserves which will eventually revolutionize economy of mining in Yukon. Such mineral resources, with interior petroleum and natural gas possibilities, and ?huge coastal hydroelectric power potential, are the foundations of a much larger future mining industry in Yukon.

Jan 1, 1958

By R. Rodgers

The Pinto Valley concentrator of BHP Copper Inc. restarted its sulfide mining operations in September 2007 to produce copper and molybdenum concentrates. During the plant production ramp up, the copper/molybdenum circuit quickly reached the copper grade and recovery targets, but the production and quality of the molybdenum concentrate continued to be a challenge. Even though several improvements in the molybdenum circuit were completed, the final molybdenum concentrate did not meet contractual specifications. After reviewing several options to improve grade and reduce contaminants, the installation of three flotation columns were chosen. The column design and construction were done using in-house craftsmen and engineers. Ten days after commissioning, the columns successfully reached a steady operation and began producing molybdenum concentrate to the required specifications, that is, high molybdenum tenors and low copper and iron content. The Pinto Valley operations, are comprised of the Pinto Valley concentrator, the Pinto Valley dump leaching and a solvent extraction/electrowinning (SX/EW) plant. The concentrator operated from 1972 to 1998 when mining and milling operations were curtailed for economic reasons. The SX/EW plant continued operations for copper cathode production. After a cessation of mining operations of almost 10 years, Pinto Valley operations began a restart project in January 2007, to bring the mine and the concentrator back into production. Copper concentrate production started in October 2007 after refurbishing and upgrading the facilities with a new DCS system and filter plant. The daily targets of the concentrator were to treat 56.7 kt (62,500 st) of ore, produce 762 t (840 st) of copper concentrate containing 27.5 percent copper at recoveries of 86 percent and produce 2.2 t (2.5 st) of molybdenum concentrate containing more than 80 percent MoS2.

Jan 1, 2010

By D E. Thorp

The mining and concentration operations of New Zealand Steel have been carried out initially from the Waikato North Head (WNH) deposit since 1969 and subsequently from the Taharoa deposit since 1972. Over the years the WNH operation has produced about 1.2 million tonnes of concentrate which has been converted into steel, while total exports to the Japanese Steel Industry from Taharoa reached five million tonnes in February of this year. Recent expansion plans both in domestic steel production and in the ironsand concentrate export market have made it necessary for the company to look closely at, among other areas, the mineral processing of the titaniferous ironsands in both deposits. This paper deals with the recent test work carried out at WNH and Taharoa on the use of the cone concentrator unit as a primary gravity concentrating unit ahead of the magnetic separation stages and as a cleaner concentrator following the primary magnetic separation.

Jan 1, 1977

By Carina Ulsen

The existing construction and demolition (C and D) waste recycling technologies and standards have been essentially focused on the production and use of coarse recycled aggregates. Very few papers focus on the production of recycled sand, although some previous results show that fine aggregates fraction represents around 40 to 60% (in mass) of the Brazilian waste and it is usually used as road sub-base or disposed in landfills. The quality of the recycled aggregate is strictly related to the content of porous and low strength phases, mainly the patches of cement remaining on recycled aggregate surface. Some technologies have already been described in the literature, even though, to the moment none of these technologies has clearly succeeded in reaching the large market available. This paper presents a summary of the main properties of the sand produced from C and D waste by tertiary crushing at vertical shaft impact crusher (VSI). Additionally mineral processing technologies were applied on the attained product, such as gravity concentration by shaking table and spirals and removal of cement paste by attrition. The main properties of recycled sand are discussed and compared to the previous C and D waste, respectively: particle size distribution, particle shape, chemical composition, cement paste content and porosity. The results demonstrates that the crushing allowed producing a VSI-sand with low porosity and water absorption due to the increasing on the content of silicates from natural rock phases and increasing liberation between these phases and porous cement paste; the particles from the attained product presented also a better shape (sphericity and aspect ratio). The attrition tests assayed on VSI recycled fine aggregates accomplished a further selective disaggregation of cement paste and other porous materials - the porosity was reduced from 10% to 7%. The concentration by shaking table at narrow sieve fractions led to a product with low porosity and reduced content of cement paste, however, concentration on spirals did not succeed since separation was performed essentially by the size of the particles. The heavy product from shaking table represented almost 75% in weight and has less than 60% recovery of CaO+LOI, and expressive reduction on porosity. The aim of producing sand from construction and demolition waste through mineral processing unit operations changes the recycling approach and contributes for up cycling the recycled sand. The exhaustion of sand deposits on Brazilian large centers, the increasing price and the construction boom encourages the development of alternative materials as construction raw material. Keywords: recycled sand, construction and demolition waste, technological characterization

Sep 1, 2012

By S. K. Kawatra, T. C. Eisele

"Coal-fired electrical power generation plants produce 56% of all the electricity in the U.S., burning approximately 860 million tons of coal annually. This results in the production of 58 million tons of fly-ash; 19 million tons of bottom ash and boiler slag, and 23 million tons of desulfurization sludge.s annually. These are a considerable disposal problem, and it would therefore be very valuable to be able to sell these residues and by-products as useful materials, rather than paying to dispose of them in landfills. However, utilization rates are currently very low, below 32% even for the most thoroughly commercialized combustion byproduct (fly-ash). This poor utilization rate is a result of the high impurity content of combustion byproducts, which makes them unsuitable for existing markets.Mineral processing techniques are useful for upgrading and utilizing combustion by-products. Fly-ash can be processed to remove unburned carbon, or utilized as a binder component in ore pelletization and agglomeration processes; bottom ash can be processed to produce certain aggregate grades; CO2 emissions can be sequestered using modified leaching techniques; and many scrubber sludge’s require processing before they can be used for producing gypsum products.The experiments described in this paper were carried out to study the application of mineral processing techniques to upgrading combustion by-products, particularly flue-gas scrubber sludge. A process was developed for upgrading unoxidized Flue-Gas Desulfurization (FGD) sludge’s by removing the primary impurity (unreacted limestone). A combination of hydrocycloning followed by froth flotation reduced the limestone concentration to as little as 1.7%, while recovering 66% of the sludge weight as a clean product. The recovered limestone was sufficiently concentrated that it could be recycled to the scrubber for more complete utilization."

Jan 1, 2003