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By Yasuo Ojima

The mainstream of copper smelting processes in the world today is a combination of Outokumpu type Flash smelting and PS (Pierse Smith) converting process. Presently it can be estimated that about 50% of the worldwide copper production is produced by the Flash smelting process and 80% by the PS converting process. PS converting process due to its operational flexibility and despite its batch character of operation has been widely used in many smelters for more than 100 years. However, an environmental issue has been pointed out related to this process because of the difficulty of handling the fugitive gases. Recently several copper smelters in the world have been newly construeted and others have executed major modification and modernization. The continuous converting process has been applied in many of them instead of PS converting process. This paper compares PS to the emerging continuous converting process and makes a prospect of the future of the copper converting process.

Jan 1, 2003

By Michael L. Clar

This volume is an annotated bibliography of published literature pertaining to the occurrence and control of surface and groundwater in underground coal mines. This literature was used to develop Volume 1 of this report, which assesses the feasibility of water diversion and overburden dewatering for underground coal mines in the Appalachian Region. Each abstract is followed by subject descriptors. the abstracts are listed alphabetically by title and are numbered consecutively. These numbers are used in the subject index to help the reader locate the appropriate articles.

Jan 1, 1981

By A. W. Stradling, M. J. Fairweather

"The selective flotation of lead, zinc and iron sulphide minerals is key to the economic performance of concentrators treating zinc-lead ores. Diagnostic metallurgy is a tool to quantify mineral behaviour as a function of particle size and liberation. The result of such analysis may be used to select preferred strategies to improve metallurgical performance. The zinc flotation circuits at three Teck Cominco operations: Sullivan, Polaris and Red Dog are compared here. This paper analyses operating data from each of these circuits. The effects of mineralogy and performance by particle size are emphasized. Metallurgical performance at these three concentrators varies substantially. Liberation size is the major factor in determining metallurgical performance. Complex mineralogy requires a fine grind to achieve effective liberation. Fine grinding results in offsetting decreases in concentrate grade through entrainment. The economic treatment of complex fine-grained deposits requires optimisation of regrind size for liberation without unduly compromising concentrate grade through gangue entrainment.INTRODUCTIONUntil recently Teck Cominco Metals Ltd. operated three mines treating zinc-lead ore. In order of increasing mineralogical complexity they are: the Polaris Mine on Little Cornwallis Island in Nunavut in the eastern Arctic, the Sullivan Mine in southeastern British Columbia and the Red Dog Mine in northwestern Alaska. Both the Polaris and Sullivan Mines have recently ceased to operate due to depletion of ore reserves.The ore type and associated gangue, mineralogy and iron solid solution vary significantly between these deposits. Table 1 summarizes some of the important differences"

Jan 1, 2003

By S. H. Ash

For many years the Federal Bureau of Mines has been investigating fires and explosions in mines, tunnels, buildings, and hazardous processes of various kinds. Means and methods for controlling and extinguishing mine fires and preventing explosions and other accidents in many hazardous processes require the collection and analysis of samples of the atmospheres surrounding the sources of ignition. Complex mixtures of gases often encountered in mines, tunnels, and industrial processes may well presage imminent danger from explosions. This report discusses some practicable methods of utilizing the analyses of samples of complex mixtures of gases in their application to the many problems that arise from their presence.

Jan 1, 1948

By Mustafa Kumral, Mehmet Balci

Strategic mine planning focuses on cutoff grade selection, capacity planning and block sequencing. Despite significant knowledge accumulated, potential value can be added to mineral sourcing by addressing various aspects. A case study on a metallic deposit with a lognormal grade distribution examines if grade/metal distribution influences cutoff grade selection. Six data sets with different shape and scale factors, but the same ore tonnage and metal quantity, are analyzed. Results indicate deposits with lower shape and scale factors are more sensitive to metal price and discount rate changes. The study also investigates the effect of economies of scale (EoS) on project value, focusing on the ratio of variable cost to total cost (capacity factor). Two regression analyses are conducted for optimal capacity planning and cutoff grade selection. The first shows capacity planning is highly sensitive to the EoS of mining and mineral-processing costs, with grade variability and metal distribution being negligible. In the second analysis, grade variability and EoS of mineral processing costs are vital for cutoff grade selection.

Sep 1, 2024

By Manjeet Chowdhry, Qingxia Liu, Phillip Choi, Zhenghe Xu

Computational chemistry methods, such as density functional theory (DFT), are powerful tools to quantify reagent-mineral interactions encountered in sulphide mineral flotation. A quantitative relationship between theoretically calculated parameters based on chemical structure of collectors and their reactivity with different metals/minerals can provide valuable insights for design and development of more powerful and tailor-made reagents offering enhanced metal/mineral selectivity. DFT calculations at B3LYP/6-311++G(3df,3pd) level were employed to elucidate the reactivity of neutral sulphide collector reagents, including thionocarbamates (TC), thioureas (TU), xanthogen-formates (XF), dialkyldithiocarbamates (DTC) and dialkyltrithiocarbonates (TTC) with different heavy metal ions (Cu2+, Zn2+ and Pb2+) in solution. The extent of delocalization of lone pair electrons of heteroatoms (attached directly to C in C=S) over C=S group was found to be the dominant factor in determining the collector’s reactivity. Order of reactivity was established as: TU > TC > XF > DTC > TTC. All the collectors showed superior affinity towards copper followed by lead. Unidentate binding was observed through sulphur atom except for xanthogen-formate for which bidentate binding mode was observed. Effect of nature of substituent groups at N and/or O atom on reactivity of thionocarbamate and thiourea was also investigated. The results obtained through DFT calculations are consistent with the experimental data reported in literature.

Jan 1, 2015

By J. A. Ruppert

The Bureau of Mines investigated methods of refining iron-contaminated zinc to marketable quality and developed a laboratory-scale process in which aluminum, added as a refining agent, reacted with the iron, forming solid Fe2Al which floated to the surface of the melt. Solids were separated by both filtration and centrifugation, using a unique type of "dipping" centrifuge devised during the work. Typical zinc recovery was 95 percent, and iron content of the metal was lowered from 0.37 to 0.02 percent.

Jan 1, 1967

By Pedro Fuertes Velazco

El presente trabajo describe el desarrollo de la compañía minera de Caravelí (Arequipa) como mina modelo -en tanto genere alta productividad en las vetas, genere su propia tecnología, así como su responsabililidad con el ambiente y las comunidades involucradas.

Jul 31, 2003

"This paper describes some of the methods and equipment used for fine milling of minerals, and gives particular attention to the Vibro Energy system.In addition, the paper describes a specific application in the gold mining industry. This is the 200 tpd plant built by Anglo American Corporation at the President Brand Mine in South Africa in 1985, now a division of Freegold. This plant treats a gold bearing pyrite flotation concentrate which is finely ground to 15 microns prior to cyanidation and carbon-in-pulp (CIP). l .0 INTRODUCTIONFree milling gold ores are those that yield acceptable dissolution and recovery of the gold following grinding to what can be described as normal fineness, frequently between 50% and 90% passing 74 microns.Increasingly, gold metallurgists are faced with ores that are refractory. The traditiona1 treatment route for refractory gal d ores and concentrates has been by roasting, but for environmental reasons this is becoming less acceptable, or in some areas of the world, totally unacceptable. New methods of treating refractory gold ores are being developed and applied in practice. These new methods include pressure and biological oxidation. Higher gold liberation can also be attained by increasing the fineness of grind, although with conventional systems there are economic limits to this.In flowsheet development and test programs on new deposits, a standard procedure is to establish the relationship between the grind and subsequent go 1 d extraction. The normal situation is that gold extraction increases as the ore, or concentrate, is ground finer. Typically, this relationship is as shown in Fig. l, where the incremental additional extraction is very small once an optimum, or economic, grind has been achieved. This generally app1ies whether the material is free milling or refractory. The limits to grinding are set by the type of equipment which is commonly in use, usually ball mills. These mills have the obvious advantage of high capacity, however, they are increasingly inefficient as finer grinds are required. In general, ball mills are used to reduce ore to some agreed percentage passing 74, or possibly 53 microns."

Jan 1, 1988

By Cristian Rodriguez, Tom BoBo, Maria Rocha, John Kemeny

Blast fragmentation depends on many factors. First of all, it depends on the specific blast design, which includes the amount and type of explosive, the blasting pattern, the timing and sequencing, and other parameters. Secondly, it depends on the properties of the rock mass, including the uniaxial compressive strength (UCS), the rock mass elastic modulus (E), the rock discontinuity characteristics (as reflected in the GSI or RMR), and the rock density. Several fragmentation models have been proposed to predict blast fragmentation based on the blast design and the properties of the rock. These models include the Kuz-Ram model and variations of this model, as well as recent models by Kim and Kemeny (2011) and others. Fragmentation models are validated and calibrated by comparing the predicted fragmentation with actual post-blast fragmentation from image processing monitoring systems.

Jan 1, 2014

By M. M. Botz

There are currently more that 460 mines worldwide that utilize cyanide for gold and silver extraction. Despite this large number of cyanide-related mining operations, there have been no published accounts during the previous 25 years of the death of humans due to cyanide as a direct consequence of major mining-related environmental incidents. All published accounts of human deaths due to mining-related environmental incidents have been the result of physical inundation with tailings or waste rock materials. It appears that major mining-related environmental incidents have not been concentrated in any geographic location, are likely to occur regardless of the size of the mining company and do not occur more frequently with a specific type of mining activity. Several cyanide treatment and recovery technologies have been widely demonstrated to reliably control cyanide levels in mining solutions. With proper use of these technologies, tailings cyanide concentrations can be maintained at levels protective of wildlife while reducing the potential for adverse environmental incidents. The development of an international cyanide code of practice or management plan is recommended and should take into consideration the adoption of a weak-acid-dissociable (WAD) cyanide standard that maintains the levels entering a tailings impoundment below 50 mg/L.

Jan 1, 2001

A New Online Detection Method for Arsenic Minerals in Process Streams

Sep 13, 2010

By John Nagy

Tests were conducted in the Experimental coal mine to study some of the factors that should be considered in fighting mine fires and to obtain data on the effectiveness of different types of extinguishing agents. The investigation was confined to class "A" fires in a zone 20 feet long, involving coal burning on the floor, on the floor and ribs, and on the floor, ribs, and roof of the mine entry. It was determined that the time elapsed between ignition and attack of the fire is very important. A fire in the early stages was found to be controlled more easily and quickly than a similar fire that had burned longer. It was also found that, under suitable conditions, a fire in the floor, ribs, and roof develops very rapidly and consequently might spread over a considerable area if not brought under control quickly. The ventilating current affects fire-controlling operations markedly. Attack in intake or fresh air is highly advantageous, the chief inconvenience being the radiant heat from the fire. Attack in direct return air was impossible for the fires tested in this investigation, because of the high temperature. Universal-type gas masks for noxious gases and smoke offered no protection against the intense heat. Approach to a fire in the return air behind a water-fog curtain is not feasible unless the direction of air flow can be reversed. In one" test fresh air was carried to the fire area with a line brattice. Although the entire controlling operation was in fresh air and masks were not necessary, it was considerably more difficult to control the fire than when a similar fire was attacked in intake air.

Jan 1, 1950

By J. R. Linney

APPROXIMATELY 5,788,000 long tons of crude ore was produced by the Eastern magnetite industry in 1946, or a drop of 26 per cent compared -with 1945. Decrease in production -throughout the industry varied from :8 per cent for the mine with the lowest reduction to 49 per cent for the mine -with the highest reduction. At the Chateaugay mine, operated by :the Republic Steel Corp. at Lyon Mountain, N. Y., 426,900 long tons of crude ,ore was produced, yielding 129,500 long tons of concentrates or a reduction of 46 per cent compared with the previous year. Owing to a strike the mine was closed down from Jan. 21 to July 29. At the Mineville mines, also operated by Republic Steel, output was 755,000 long tons of crude ore or a reduction of 49 per cent compared with 1945. The yield from the crude ore production consisted of 51,500 long tons of lump ore and 380,000 long tons of concentrates. The Mineville plant did not operate from March 17 through July 28, on account of the strike. The Fisher Hill mine, which produced 93,000 long tons of crude ore, included in the above figures, has not operated since March 17, 1946.

Jan 1, 1947

By Michael MacMillan

The mining industry has always operated under intense public scrutiny. Community expectations, investor pressures, regulatory obligations, and environmental oversight create a uniquely complex communications environment. In recent years, technological change, climate urgency, and geopolitics have reshaped how the industry communicates its role and value. The rise of artificial intelligence in the information ecosystem represents yet another fundamental shift. As AI evolves, an organization’s reputation will no longer be shaped solely through human interactions, media coverage, social activity, or corporate disclosure. Increasingly, public understanding depends on how AI systems interpret and represent company information. These systems influence search results, conversational tools, news aggregation, social discourse, and even investor intelligence platforms. As AI-generated summaries, answers, and narratives become the default interface for stakeholders, they also become authoritative in shaping trust. For mining companies, this creates both risk and opportunity. The organizations that recognize how AI reads, prioritizes, and amplifies information will be better positioned to build trust. Those that remain silent or rely on traditional communication methods may find their reputations being algorithmically defined without their participation. This paper explores how mining companies can proactively engineer their reputations in the age of AI.

Jan 1, 2026

By A. Nieto

A dump edge and vehicle proximity warning system is being developed at the Colorado School of Mines using GPS and wireless local area networks to improve the safety of off-highway trucks in open pit mines. After two years of research, software development, and testing in the laboratory, field tests are currently being carried out at operating limestone quarries and open pit mining operations to evaluate the effectiveness of the system under rugged operating conditions. This paper describes the progress made on this NIOSH-funded project and discuss, tests carried out recently, at the Morenci open pit copper mine in Arizona.

Jan 1, 2002

By Doss H. White

Alabama's non fuel mineral industry produced $560.6 million of mineral commodities in 1990. This was an increase of $99 million over the 1989 value and a new State record, a record achieved despite the slowdown in the national economy. This was the first year that Alabama's mineral value exceeded one-half of 1 billion dollars. The value of stone and cement, the two leading mineral commodities in terms of sales, increased $71 million over that reported for 1989 and was the primary reason for the new mineral value record. The State ranked 21st among the 50 States in total mineral value and contributed 1.68% of the total U.S. mineral value of $33.3 billion.

Jan 1, 1992

By Charles L. Kimbell

On the basis of world production data alone, 1985 appears to have been a year in which the world's mineral industry took another step upward in its recovery from the very poor years of 1981, 1982, and early 1983. Despite a drop in the output of crude oil, which was the single most significant crude mineral product from the viewpoint of value, the estimated value of world crude mineral production advanced by 3.4% to about $1,054 billion constant 1983 dollars, with output increases logged for nearly two-thirds of the commodities and forms of commodities for which the U.S. Bureau of Mines calculates a total world output. However, the economic well-being of any industry or group of industries cannot be measured solely in terms of the volume and/or value of its production, and examination of statistics reflecting other aspects of mineral industry performance shows that 1985 was a less than ideal year in many respects. In the case of consumption of mineral commodities, although there were gains registered in diverse sectors such as iron and steel, aluminum, fertilizer materials, solid fuels, and gaseous fuels, there were also proportionally small but notable declines in use among the older major nonferrous metals (copper, lead, tin, and zinc) and in the all-important liquid fuels. In the case of international trade in mineral commodities, although comprehensive data for 1985 were not yet available, there were indications that the value may well have fallen below the estimated 1984 level of $632 billion, although the volume may have increased slightly. This, if true, would be chiefly the result of declining prices of mineral commodities, and indeed, price declines were noted for a number of significant materials in terms of current dollars, and even more would register declines if calculated on the basis of constant dollars, adjusting for inflation.

Jan 1, 1987

By C. W. Spencer, J. T. Smith

GRAIN-BOUNDARY surfaces are penetrated by a liquid phase when the liquid-solid interfacial tension is less than one-half the tension of the grain-boundary surfaces. Grain growth may occur in the presence of this liquid phase. burke1 reports that grain growth of this nature has been observed in two-phase ceramic systems. He suggests that the presence of a grain-boundary liquid may accelerate or decelerate the

Jan 1, 1963

By Herbert Tomlinson

The United States Bureau of Mines has engaged in a study of the conditions under which coal mine accidents, resulting in the loss of life, limb, or time to the injured person, occur from falls of roof and coal. This publication is devoted to the results of a study conducted in the coal mines of the Book Cliffs and Wasatch Plateau coal fields of Utah. To show the necessity of this study, a statement of the fatalities that have occurred during the period 1928-1930, inclusive, in the bituminous mines of the United States and of Utah, is presented (Table 1), followed by a brief description of this Utah district, its coal beds and immediate roof, thickness of cover, dip of coal beds, methods of mining, supervision, roof testing and timbering for roof support, all of which are factors in any plan devised for preventing accidents from falls of roof and coal.

Jan 1, 1932