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By Oscar Weiss

An aerial magnetometer survey was carried out by the author's geophysical organization over the Vredefort dome, where Witwatersrand beds are wrapped around a granite plug 25 to 30 miles in diameter. The well- known magnetic shales of the Lower Witwatersrand system (to be referred to as LWW) give strong negative anomalies over the out-cropping portion of the dome. This is unusual as these same shales -cause positive anomalies over large areas near Johannesburg and along a strike of 130 miles between the East Rand and Klerksdorp. It is suggested that the negative polarization is caused by heat and stresses connected with the doming. This negative polarization of sedimentary beds, which usually cause positive anomalies, is a good example of how "magnetic lows" can be caused by "structural highs." Significant magnetic anomalies should be tested by gravity and seismic methods irrespective of the sign of the anomalies.

Jan 1, 1949

By H. A. Dierks

The work and costs involved in controlling three large fires in abandoned mines in the anthracite region of Pennsylvania are presented in detail. The work was done under authority of Public Law 89-4. Three basic control techniques were successfully employed by the Bureau of Mines: (1) forming underground fire-containing barriers by systematically flushing incombustible material into mine voids, (2) excavating an isolation trench around the fire area, and (3) complete excavation of hot and burning material in the fire area. When methods 2 and 3 were used, the excavations were subsequently back- filled with incombustible material. Preliminary location of fire perimeters by the standard use of patterned 6- and 8-inch-diameter boreholes is discussed. Investigations into air-borne infrared scanning, shallow subsurface thermal anomalies, and the use of helium to trace the movement of mine air currents are covered. Although they are costly and time consuming, boreholes have proven to be the most efficient means to date of obtaining necessary subsurface fire data. Infrared scanning was ineffective in delineating fires under more than 30 feet of cover. Helium-tracing was shown to have a good potential for determining possible hazards to adjacent residential areas from traveling mine fire gases.

Jan 1, 1971

The grinding of ore to a size that is conducive to the extraction of minerals by leaching or flotation is an essential and expensive component of most mineral-processing operations. Overgrinding results in reduced flotability of the minerals, as well as problems in the filtration and thickening processes, while undergrinding leads to a product in which the minerals have not been exposed, and cannot be leached or floated effectively. Furthermore, coarse material causes settling in thickeners and agitator tanks. It is therefore essential, from the perspective of both operational and extraction efficiency, to grind the ore to an optimum size fraction. A well-run milling circuit will yield a product within a narrow size band and at a high throughput. Although the effective operation and control of milling circuits with their many operating parameters is widely acknowledged as a complex as well as a critically important operation, the benefits of such control are difficult to quantify. This is due to the difficulties in relating more stable operation to increased recovery of the valuable components in downstream processes.

Jan 1, 1993

By Chee S. Theng

As the 2016 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2016 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 340. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2016 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH) and special-issue articles on process development testing. The 2016 Transactions consists of a total of 65 technical papers, encompassing all 21 papers published in 2016 in the Technical Papers Section of Mining Engineering (Vol. 68) and all 27 papers published in 2016 in Minerals & Metallurgical Processing (Vol. 33). Additionally, this volume contains 17 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2016 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2016

By Da-Qiang Cang, Qingde Wang, Wei Wang, Wen-Bin Dai, Min Guo, Yu Li

Utilization of both slag and its heat for hot slag is a great challenge for iron and steel industry. Many methods of hot slag modification for directly converting hot slag into value-added materials were researched in recent years, and waste heat of hot slag could thereby be transformed into inner energy or chemical energy of the materials. In this paper, an experiment of converting hot slag directly into glass ceramics by hot slag modification method was conducted. A cooled modifiers mainly composed of fly ash were firstly heated though a cyclone furnace and then fell into a molten bath to mix with hot steel slag. Half of hot slag was used as raw materials and accordingly about half energy consumption, about 5MJ/kg for melting raw materials was saved in the process compared with that of traditional producing method. Frit quenched from the modified hot slag had a higher basicity of 0.6-0.7 than traditional frits in order to reduce the needed amount of cold modifiers and accordingly utilize more hot slag and its waste heat. Glass ceramics were further prepared from the frit and a heat treatment of one-stage method is more suiter to such frit than that of two-stage method. The glass-ceramics with basicity of 0.6 and heat-treated by one stage method had the best performance with bending strength of 146.46 MPa, Vickers hardness of 6.79 GPa, water absorption rate of below 2% and shrinkage rate of around 10%.

Jan 1, 2015

By I. Ruiz Bustinza, L. F. Verdeja, Daniel Sbarbaro, R. Parra, J. Mochón

The oxidation of sulfides is a complex process involving gaseous products and intermediate species given rise to emission and absorption spectra which carry out important information about the reaction process. This information could be used for on line monitoring of pyrometallurgical reactor if the appropriate sensors were available. We present in this paper an analysis of the concept that has been successfully applied in iron and steel making industry, as well on fuel combustion control, where the spectra measurement gives the possibility for online monitoring and automatic control of high temperature processes. This concept has not been widely applied in the nonferrous pyrometallurgical primary production. The design of new sensors is discussed from the analysis of spectra measurements during flash combustion of copper concentrates at laboratory scale.

Jan 1, 2015

By P. R. Jones

"The paper describes the CDN$400 million expansion at Hudson Bay Mining and Smelting Co., Limited’s operations. The company has continuously produced copper and zinc at the Flin Flon metallurgical plant since 1930. The paper details the company’s operational turnaround since 1995 and “The 777 Project” which includes two new mines, expansion and modification of the concentrators, expansion of the zinc pressure leach plant, a new zinc electrolytic cellhouse and modifications to the copper smelter gas handling system to reduce ground level gas emissions. IntroductionHudson Bay Mining and Smelting Co., Limited (HBMS) was incorporated in 1927 to mine and process the world-class Flin Flon copper and zinc orebody. Ore concentration and metallurgical facilities were constructed in Flin Flon. The metallurgical complex capability is currently 89 000 tonnes of copper metal and 98 000 tonnes of zinc metal from both HBMS and purchased concentrates.Flin Flon, with a population of 7000, is in Manitoba and partly in the province of Saskatchewan. The location is isolated with Winnipeg 800 km to the south and Saskatoon 500 km southwest.Today, three underground mines feed the Flin Flon concentrator, one feeds the Ruttan concentrator at Leaf Rapids, 200 km to the north of Flin Flon, and Chisel North mine feeds the Snow Lake concentrator (Fig. 1).The Flin Flon volcanic massive sulphide proximal and distal orebodies are within the Flin Flon greenstone belt which stretches from the west of Flin Flon to the east of Snow Lake, a distance of 250 km. The belt is approximately 100 km wide before disappearing below the paleozoic cover to the south."

Jan 1, 2001

By Tania Schmid, Marco Portal Valdivia, Sandra Nowosad

Today’s mining industry faces rapid transformation driven by automation, climate responsibility, and ESG demands, requiring more than technical expertise. Future mining engineers must blend engineering excellence with key human skills such as communication, leadership, resilience, empathy, adaptation to change, curiosity and lifelong learning. Based on two recent surveys, one to senior leaders with over ten years of experience in the mining industry and a second, focused on understanding the perceptions of young professionals, this paper explores which skills become core competencies by 2030 for navigating complexity, leading responsibly, and enabling sustainable transformation. Furthermore, it also examines how educational institutions can adopt strategies to foster the development of these critical skills, preparing future mining talent for evolving challenges.

Feb 22, 2026

By F. W. Horton

Investigation of an extensive deposit of chromite-bearing actinolite-talc schist situated on the summit of Casper Mountain, 10 miles south of Casper, Wyo., was one of the first projects Undertaken by the Bureau of Mines under the Strategic Materials Act (Public 117, 76th Cong., Ch. 190, 1st sess.), for which an appropriation became available August 9, 1939. During the previous summer; the Geological Survey? made? a magnetometrical survey of the area in which the schist occurred. It was exposed in several small lenses and two larger ones aggregating about 19?acres in area. Although the occurrence of chromite here had been known for many years, the only work done on the deposit was the digging of? a few shallow pits on some of the more promising outcrops. From August 23 to December 3, 1939, the Bureau of Mines investigated the larger of the two main schist bodies. Twenty-four trenches having a total length of 8,073 feet were dug across the deposit, and its subsurface extension was explored by 3,623 feet of diamond drilling. Over 32 tons of samples were shipped to the Metallurgical Division of the Bureau of Mines at Reno, Nev., for reduction, analysis, and ore testing. In all, there were 853 individual samples. Geological maps, based upon examination of outcrops, trenches, and drill cores, as well as a contour map of the area were made by the Geological Survey.

Jan 1, 1949

By G Phillips

The Merlin project is situated 130 km south of Cloncurry in North West Queensland, Australia. It is located within the Pre-Cambrian Mt Isa Inlier and is grouped within the Eastern Fold Belt. The host rocks are metasedimentary rocks of the Proterozoic Kuridala and Staveley Formations adjacent to the Mount Dore Granite.Merlin zone represents part of the Mount Dore polymetallic deposit containing copper, zinc, silver, gold, lead, cobalt and most recently has been found to host molybdenum mineralisation. This is intimately associated with economic grades of rhenium, a naturally occurring metal that is an important component of high temperature aircraft engines. The host rock sequence is a 200 m thick zone of metasediments sandwiched between competent granite in the hanging wall and brittle quartzite in the foot wall. A distinct shear marks the contact between the granite and metasediments. The host rocks are comprised of three main rock types: black shale, phyllite and altered banded calc-silicate.Mineralisation dips to the east at approximately 45° in a package of fine grained pelites and banded calc-silicates. The top 150 m of the sequence is typified by black shale and phyllite. The lower 50 m is typified by pink banded calc-silicate. The main molybdenite zone is located at and parallel to the pelite-calc-silicate contact. Down dip, the zone splits into two or three veins hosted by the calc-silicate rock suite and haloed by thin, steep dipping, stylolitic molybdenite veinlets.The deposit was discovered in 2008 by routine infill reverse circulation sampling conducted for the Mount Dore copper deposit. One hole penetrated below the main target Cu horizon and intersected visible molybdenite. During 2009 and 2010 a 50 × 50 m diamond drill pattern delineated a total mineral resource of 6.7 Mt @ 1.3 per cent Mo, 23g/t Re, 0.3 per cent Cu (mostly Indicated Mineral Resource with minor Inferred Mineral Resource). The resource has been estimated using ordinary kriging within grade domains. Access to the deposit has commenced via a decline and production through the nearby Osborne flotation concentrator (70 km south) is expected in 2012. All facilities and resources are fully owned and operated by Ivanhoe Australia Limited, a public listed company on the Australian and Toronto stock exchanges.

Aug 22, 2011

By A. K. Sinha

Inspite of the growing demands worldwide, thermal coal must compete in the market both in price and quality. The design and performance efficiency of coal preparation plants is thus crucial to the survival and profitability of a coal industry. While the coal recovery influences the cost of production, the quality produced by a preparation plant determines the selling price. Several coal preparation plant simulation models have been developed in recent years to help Improve the performance of coal preparation plants. A research project was recently conducted at Southern Illinois University to evaluate the practical applicability of such a model. The results of this study are presented and discussed.

Jan 1, 1986

By Paul L. Broughton

"IntroductionThe coal deposits, all of lignite rank, of economic interest in Saskatchewan are associated with the Ravenscrag Formation (Paleocene). Several Cretaceous formations have less significant lignite accumulations (Broughton, Irvine and W'hitaker, 1974). The Swan River Group (lower Cretaceous) and Judith River Formation (upper Cretaceous) have the only coalbearing strata in the shallow subsurface of central Saskatchewan. The Swan River Group coalfield is relatively small and underlies only 15 sq km of the surface approximately 40 km south of La Ronge, Saskatchewan. An estimated 36 billion short tons are within 45 m of the surface. No reserve estimates are known to have been calculated for the coal-bearing Judith River Formation exposed at the surface in the vicinity of the South Saskatchewan River valley in west-central Saskatchewan. Although no coalfields have been delineated, lignite beds up to 1.8 m thick have been intersected in test holes. The coal-bearing upper Cretaceous and lower Tertiary strata of the northern Williston Basin extends the full width of southern Saskatchewan for 650 km, and from the United States border 120 km north to 50° latitude (Fig. 1). Only the coalfields of the Ravenscrag Formation, because of their economic interest, will be considered further. There are four major coalfields. They are, from east to west: Estevan, Willow Bunch, Wood Mountain and Shaunavon (Cypress) coalfields. Cumulative lignite seam thickness for each basin is 10 -15 m (Figs. 2 and 3). The origin of each coal basin, resource calculations, seam stratigraphy, and mining activity are discussed. Regional Setting The Williston Basin is an ellipsoidal depression in the Precambrian basement, centered in western North Dakota and marginal to the exposed craton of northern Saskatchewan and central Manitoba (Fig. 1). The sediments of the basin range from Cambrian to Pleistocene in age and have a maximum known thickness of 4614 min western North Dakota. A maximum of 3200 m is recorded in southern Saskatchewan. Most structural deformation is late Cretaceous to early Tertiary (Paleocene) in age, coinciding with the Laramide Orogeny. The pre-Laramide Williston Basin, with a depocenter near Williston, North Dakota, began developing during the middle Ordovician, or possibly earlier."

Jan 1, 1985

By Granville S. Borden

TAXES in general are onerous and are not a pleas- ant subject for discourse. There are, however, some very cogent reasons why we should dedicate a part of our thoughts and services to the solution of our taxation problems: The happiness of every individual in the United States depends on the maintenance of a stable government. The collection of taxes is an indispensable function of a stable government, and the power to collect taxes depends in part on the question whether taxes are fair and equitable. As representatives of the mining industry it is our duty to .protect it from tax burdens that are discriminatory or- unjust, As citizens we find that taxation is incessantly endeavouring to unravel the knots in our purse-strings. Many members of the Institute may be consulted .by clients on taxation problems, especially the phases which re- late to depletion and valuation. It is the hope of the writer that the discussion of some of the current depletion and valuation problems will stimulate interest in the problems, and as a consequence of this new interest facts will be ventilated, opinions rendered and services performed, which will be a means of solving the problems to the satisfaction of all parties interested.

Jan 1, 1929

By J. E. Dooley

A mass spectral scheme of analysis was devised which can be used to identify individually a single compound from a larger group of similar compounds. Mass spectra for 32 alkyl aryl sulfides are provided for future reference work, and analytical correlations used in producing the analytical scheme are discussed. Some of the correlations show that base peaks are either the same mass as the parent peaks or may be derived from cleavage alpha to the sulfur atom with migration of one hydrogen to the sulfur atom. Other spectral consistencies provide means of separating ortho-, meta-, and paratolyl arrangements in an overall analytical scheme. Determinations of chain lengths and separation of isomeric species are also discussed.

Jan 1, 1972

By D Howe

The Athena gold deposit was discovered in 2007 by Gold Fields Australia Ltd, at the St Ives Gold Mine, 35 km southeast of Kambalda, Western Australia. Gold anomalism was identified in sheared Paringa Basalt as a result of a regional scale aircore drilling program, in association with geophysics. In the 18 months following discovery, the deposit was intensely drilled and by June 2009, it was announced that the Athena deposit contained an ore reserve of 1.7 Mt @ 5.6 g/t for 316 koz. This was followed by a feasibility study, and as a result mine development commenced in November 2009.The Athena mineralisation is hosted in a discrete, north-south striking, steep to moderately dipping shear zone within the southwest dipping Paringa Basalt. Vein intensity has a strong correlation to grade and vein type varies from early thin quartz-albite-sulfide (pyrite and/or pyrrhotite) shear parallel veins to strong brecciation and irregular veining with quartz-albite-actinolite-biotite-pyrrhotite infill. The geology preproduction process developed at the Argo mine was refined and improved following a business improvement project. The aim of the process is to construct detailed geological interpretations prior to development allowing informed mining decisions to be made. The process delivers significant cost savings and revenue enhancements.The development of macroscopic classification scheme was critical to determine ore or waste in the early phases of mining. The Style of Deformation, Alteration and Veining (SAV) Code was the result, and has been enhanced as greater geological knowledge is gained over time.

Aug 22, 2011

By R. E. Radabaugh, J. M. Brown, J. S. Merchant

The Gilman district is on the northeast flank of the Sawatch Range in central Colorado. It has yielded a total of 10,000,000 tons of ore having a value of over $250,000,000. Paleozoic sediments intruded by a Tertiary quartz latite sill and unconformably overlying Precambrian intrusives and metasediments comprise the country rock of the area. The sediments strike northwesterly and dip 8° to 12° northeasterly. Structures in the Precambrian are related to the Homestake shear zone of the Colorado mineral belt. Only minor folding and faulting occur in the sediments. The principal ore bodies are massive sulfide replacement deposits in carbonate rocks. They consist of long, pipe-like mantos in the completely dolomitized Mississippian Leadville Limestone and funnel-shaped chimneys of copper- silver ore cutting across the Mississippian and Devonian strata. Mineralization is continuous from the chimneys into the mantos. The principal ore bodies are roughly in the shape of a four-tined fork which points up dip. Smaller manto deposits occur in the Cambrian Sawatch Quartzite, and fissure veins are present in the Precambrian rocks. The principal minerals in the mantos are marmatite and galena in a gangue of pyrite and manganosiderite. The chimneys consist of a central core of pyrite with erratically distributed chalcopyrite, tetrahedrite, freibergite, and occasional galena with a shell of zinc ore on the outer margin. Both the chimneys and the mantos are surrounded by imperfect shells of manganosiderite and sanded dolomite. The mineralization is of Laramide age. Hydrothermal alteration affects all rock units to varying degrees. Clay mineral alteration halos occur around the ore bodies. Hydrothermal solutions have developed sanded rock, rubble filled channels, and banded zebra textures, principally in the Leadville Limestone. Structural control of the ore bodies is not well defined. Both the location of the district and the chimneys are probably related to basement structures. The mantos are largely controlled by stratigraphic factors and a pre-Pennsylvanian karst topography in the Leadville Limestone, which were modified by hydrothermal activity, and by weak zones of northeasterly trending faults.

Jan 1, 1968

By R. A. Beall, S. L. Ausmus

The development of a completely water - free expendable graphite mold material , useful for reactive metal castings , has been detailed . Mixing and curing variables have been evaluated both by physical testing of the material itself and by castings of titanium , zirconium , and hafnium . The blend of powdered graphite , cornstarch , dextrin , cereal binder , linseed oil , and Carbowax -4000 is a successful mix when mulled in a carbon dioxide atmosphere , and properly cured and fired . The primary advantage of this material is its adaptability to standard foundry techniques ; i . e . , core blowing and hand ramming . Temperatures in the curing and firing cycles do not exceed 960 ° C , and no vacuum firing is required .

Jan 1, 1964

By D. Harrington

The desirability of efficient control of air currents, and the necessity of supplying metal-mine workers with better and safer working conditions, has created an active interest in metal-mine ventilation, especially in recent years. This paper discusses the subject both with regard to efficiency and economy, as well as safety and health. It is based on personal observations of the writer from over four year's study of metal mines in six States, in which more than 50 mines were visited. Many of these were studied in detail; in all several thousand working places were examined, and readings taken relative to ventilation run into the tens of thousands.Object of ventilating metal mines:Whereas in coal mines ventilation is generally regarded as essential, in many metal mines, especially shallow ones, the operators pay little attention to ventilation, or ignore it altogether. Recent shortage of labor, and numerous accidents to which State compensation laws have directed attention, are causing metal-mine operators to regard ventilation more seriously, especially in deep, large mines.There is, in fact, greater necessity for adequate ventilation of metal mines than of coal mines. The latter require air currents to remove explosive gases and the fumes of explosives, but metal mines, in addition to the need of removing fumes of explosives, and occasionally explosive gases, frequently have need of removing dusts dangerous to health, reduction of high temperatures and high humidity, and removal of inert but unhealthful gases like CO2 and nitrugen. The generally accepted superior healthfulness of coal miners as compared with metal miners, is probably due in large part to the better air circulation in working places of coal mines.

Jun 1, 1920

By Yves Prévost, Guy St-Amant, Guillaume Dion

In 2010, the foreseen increase of copper grade in feed concentrate at the Horne Smelter was a significant challenge to maintain a steady copper flow throughout the process. The Horne Smelter process includes a Noranda Reactor, a Noranda Converter, pyro refining vessels and anode furnaces. Of the many challenges involved, improving the single casting wheel performance was one of the key topics. Its reliability had to be improved to meet the new production objectives, as anode copper production was to increase from 170 000 to 225 000 tonnes/year. A multidisciplinary team was dedicated to improve the casting wheel availability. The improvement project allowed pinpointing failure modes and reviewing operational and maintenance practices. The common understanding developed by the team allowed improving small components with a high gain-to-effort ratio. The project allowed reaching operational targets without any significant investment. INTRODUCTION In operation since 1927, the Horne Smelter, located in Rouyn-Noranda, in Quebec, has undergone several technological changes since its original construction. Built to smelt the Horne mine concentrates, the smelter also accepted some local custom feeds from the first years of operation. When the Horne mines stopped production in 1976, the plant became a 100% custom smelter. With the development of the Noranda Reactor (1973) and Noranda Converter (1997), the Horne smelter increased its productivity and improved its environmental performance. Continuous improvement of the Horne process allowed maintaining a high level of flexibility in the operation of the smelter, while improving its overall capacity.

Jan 1, 2019

By C. E. Armantrout, H. Kato, M. I. Copeland, M. Krug

The investigation of the nickel - gadolinium phase diagram was undertaken to determine the alloying behavior of these two metals . The data from meltingpoint determinations , thermal analyses , metallographic examinations , and X- ray diffraction analyses revealed a phase diagram with three eutectic points and seven intermetallic compounds . Very limited solubility of the phases in each other was observed . The five phases , Ni Gd , Ni , Gd , Ni Gd , Ni, Gd , and NiGd¸ , melted incongruently at about 1,300 ° , 1,270 ° , 1,180 ° , 1,070 ° , and 775 ° C , respectively . Ni Gd and NiGd melted congruently at approximately 1,550 ° and 980 ° C , respectively . Four of the compounds were determined to crystallize in the hexagonal system : Ni Gd , Ni Gd , Ni , Gd , and Ni Gd . Ni Gd was determined to be cubic and NiGd , orthorhombic . The crystal system of NiGd was not determined . The eutectic points occurred at 13 , 67 , and 85 wt pct gadolinium , and the isotherms at 1,290 ° , 890 ° , and 700 ° C , respectively .

Jan 1, 1964