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By Duane L. Abata

Toxic gases produced by the detonation of six explosives were measured in an underground hardrock metal mine during actual mining operations. The six explosives included two semi-gelatin dynamites, three slurry explosives and an ammonium-nitrate, fuel-oil/ammonia dynamite combination. Explosives were detonated at the face of a drift and the toxic gases produced by the detonation were trapped to the end of the drift by a bulkhead located a short distance away from the face. Toxic gas concentrations were then measured with direct readout instruments and together with the containment volume, the toxic gas volumes per mass of explosive were calculated. Toxic gas measurements were found in the following ranges (ft3/lbm): N02 0.010-0.035; N02, 0.003-0.019; CO, 0.08-0.30; S02, 0.00-0.05; and C02, 0.7-1.8. Results showed that toxic gas production (ft3/lbm) correlated with the densities (kg/m3) and energy densities (kJ/kg) of the explosives tested.

Jan 1, 1978

Comparative Studies on Balls Versus Spheroidal Tetrahedrons Working Media to Ore Grinding in an Industrial Drum Mill

Sep 13, 2010

By K. L. Whitehead

An examination of 60 mines, 11 illumination hardware manufacturers, and Q mobile face-equipment manufacturers was conducted to determine the state of the art of mine-illumination hardware, define lighting system installation and maintenance problems, and assess personnel acceptance of lighting. Longwall and mobile face-machine illumination were studied. Major problems on room and pillar installations include damage of exposed components, electrical failures, and reduced lamp life, with extreme variability in the degree of these problems. Most longwall systems had low or moderate maintenance requirements, cable damage being the most significant problem. Most mobile face-equipment operators liked their machines' lighting systems, but many complained of glare and other problems. Longwall lighting was unanimously accepted by face personnel, and most complaints were minor. Based on the survey, general installation and maintenance guidelines have been established, addressing hardware design aspects, approaches proved effective to minimize problems, and improper practices noted which are detrimental to effective lighting.

Jan 1, 1981

By C. Hutton

"SynopsisThe last commodities supercycle (2003 to 2011) was characterized by a belief in volume at any cost, where absolute output was deliberately prioritized over productivity considerations. This practice fuelled overoptimistic forecasting and planning, which in turn contributed to the economic crisis that followed. The sudden collapse of commodity prices has resulted in mining companies scrambling to find the right balance between optimizing current operations and preserving sufficient flexibility to grasp future opportunities. The runaway costs of building and operating mines have almost squeezed out profit margins, while lower ore grades are inflating production costs. Mining companies therefore need to look at the business with fresh eyes, and develop strategies to attract equity capital as traditional approaches are simply not working anymore. This is especially so in the context of a dwindling investor base that continues to demand greater returns, despite a significantly lower appetite for risk. This paper revisits the micro-economic concepts and demonstrates how pressure from shareholders to prioritize output contributed to spiralling costs and value destruction. Practical techniques are described to model cost curves to optimize a Mineral Resource endowment and address the need to rightbalance a business and preserve agility.IntroductionHenry Lazenby (2014) for the Mining Weekly writes, ‘Bruised and battered, the global mining industry today is undergoing a sea change. Practices and policies that might have worked wonders in the past are not as relevant today, and new approaches to running profitable mining operations need to be found.’ One significant practice the mining industry had during the last commodities supercycle (2003 to 2011) was chasing volume at any cost; absolute output was deliberately prioritized over productivity considerations (Goldsmith, 2013). Lazenby contends that in the face of falling and volatile commodity prices, many mining majors ‘across all commodity groups are currently grappling with sagging profits and low company valuations. This is often regarded as the result of the were in pursuit of growing their output at all costs in a high commodity price environment.’ Lee Hodgkinson, KPMG’s Canadian mining industry leader and quoted by Lazenby, says that ‘mining companies are now trying to find the right balance between optimizing current operations and preserving their agility to grasp future opportunities. The runaway costs of building and operating mines have almost squeezed out profit margins [whilst] lower grades of ore are inflating production costs. Mining companies need to look at the business with fresh eyes, and develop strategies to attract equity capital as it seems clear that some of the traditional approaches to the mining business are simply not working anymore."

Jan 1, 2015

Development of Technology for Complex Uranium Ores Processing on the Flotation Process Basis

Sep 13, 2010

By D. R. Shoemaker, H. W. Judges

A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first produc¬tion is scheduled for early 1983. The company expects full capacity-9 Gg of molybdenum per year-to be reached in 1984.

Jan 6, 1980

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to all aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, and Treasury, and the Central Intelligence Agency, whose primary mission is the collection of data in non mineral subject areas, but in which the mineral industry is a component.

Jan 1, 1982

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

Geophysical Abstracts 1 - 86 were issued in mimeographed form by the Bureau of Mines; Abstracts 87 - 111 were published in bulletins of the Geological Survey; Abstracts 112 - 116 were issued in mimeographed form by the Bureau of Mines as Information Circulars 7256, 7257, 7267, 7273 and 7285. 1. GRAVITATIONAL METHODS 7380. Dryden, H. L. A reexamination of the Potsdam Absolute Determination of Gravity. Jour. Research Nat. Bureau of Standards, vol. 29, No. 5, 1942, pp. 303-314.

Jan 1, 1944

By K H. Esbensen

The Theory of Sampling (TOS) has made remarkable strides and has witnessed a suite of achievements over its ~65-year history; especially in the last 15 years, since organised work began for the erstwhile fragmented sampling community (2003). Theory and practice have been very well exposed and disseminated, as witnessed in the successful series of the World Conference on Sampling and Blending (WCSB) events and other dedicated sampling and mining conferences in Australia and South Africa. At this WCSB8 occasion we fittingly devote a section of our conference to celebrate the life and monumental achievement of Pierre Gy, the originator of the Theory of Sampling; a special issue of TOS Forum was recently published to the same purpose. But TOS is most emphatically not a finished work.Here I try to look into the future with a personal view: TOS – what’s next? Commensurate with this objective there is offered some out-of-the-box thinking. The purpose is to try to zoom in on probable additional future aspects of TOS and its application compared to the first 15 years of our common journey. There are bound to be lacunae here-and-there across the vast application horizon delineated, which is as it should be, as this lecture is meant to initiate a broad(er) debate – and readers may agree with all, parts, or none of the topics presented. All is well that furthers this debate.CITATION:Esbensen, K H, 2017. Theory of Sampling – what’s next?, in Proceedings Eighth World Conference on Sampling and Blending , pp 29–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By J. E. Nesset

"I had been requested earlier this year by MetSoc, our sister society of CIM, to contribute a chapter on technical developments in Canadian mineral processing over the past 50 years to their 50th Anniversary volume. Accepting the challenge of assembling such a chapter seemed at first a reasonably straightforward task, until one realises that the list of contributions by Canadians to mineral processing over this period has been more than just significant. It turns out to have been an extraordinarily fertile time for innovation and impact for Canadian-based technology. The list is necessarily a subjective one, however I had no trouble identifying twenty technology developments that are clearly outstanding, and there are undoubtedly others. As much as possible, I approached the individuals themselves who played key roles in each technology and asked that they tell the “story”. Without exception, all who were invited accepted eagerly and delivered more than I had hoped for. The technologies have been grouped into those that are truly Canadian innovations, such as the Knelson gravity concentrator and the McGill gas dispersion sensors in flotation, and technologies where Canadians and Canada played a very significant role in their success and implementation, such as AG/SAG grinding and ion-beam surface analysis. Also included are what may be termed technology transfer initiatives and institutions that have risen to a world class level, such as SGS Lakefield and the Canadian Mineral Processors Society of CIM. The challenge is now for the coming generation to continue this record of innovation and contribution to the industry, and that includes the (mostly) Canadian mining and metallurgical companies who have taken the longer term view and supported many of these initiatives, through their critical early years, with both financing and project sites for these ideas. Let us hope that the current trend of mining company globalization will not dampen their enthusiasm to participate. This plenary presentation will highlight many of these technologies, the individuals behind them, and their significance to the mineral processing industry."

Jan 1, 2012

By Abouzar Vakili

Longwall Top Coal Caving (LTCC), as the most attractive method for thick coal seams, has been suffering from insufficient geomechanical understanding for the past few years. Cavability without doubt is the most critical geomechanical issue associated with the top coal caving method. A discontinuum method has been used for comprehensive modeling of LTCC operation by using the Universal Distinct Element Code (UDEC). In addition Particle Flow Code (PFC) and Phase2 were used as support for the caving mechanics analysis. Although the previous researches of gravity flow in caving operations neglected the effect of continuous span expansion, it has been observed in this study that face advancement has a great impact on roof symmetrical behavior. The amount of symmetry fluctuates between different face distances. Horizontal displacement seems to be the best indication for roof symmetrical evaluations. Two critical caving conditions have been modeled and parameters such as horizontal displacement, caving angle and recovery rate have been compared thoroughly. Results show that unsymmetrical behavior on the roof is closely related to face stability.

Jan 1, 2007

By P. D?Elia

Following a study by NIOSH on the availability of teams in the U.S. as well as existing training sites and their capabilities, the Penn State University, leaders of the Pittsburgh Section of SME, providers of mine rescue equipment, and industry sponsors united to establish and make fully functional a student mine rescue team at Penn State University. With the growth of MERD and mine rescue competitive events at Missouri S&T, the Mine Training and Technology Center in PA, and at Colorado School of Mines Edgar Mine, a critical mass of effective training venues were made available to help student teams progress and develop mine rescue skills. The challenges to be met in creating and developing a student mine rescue team will be discussed. The rewards from this type of effort will be the quick capability of graduates from mining engineering programs to be involved in not only mining operations, but industry mine rescue teams and other leadership roles as well.

Jan 1, 2012

The upper amphibolite-grade mctasediments of thc rinaroo area, North Queensland, form part of a regional aurcole to the large Tinaroo Batholith and are the stratigraphic equivalents of the Hodgkinson Formation of gencrally low metamorphic grade. There is no evidence of any lithological unconformity.The higher grade metasediments have a more complex deformation history than is typical for thc surrounding region and this may bc due to one or a combination of two factors; an additional strain componcnt associated wilh the intrusion of Ihe Tinaroo Batholith, or a more marked finite strain response to the overall regional stress field within hotter. more ductile rocks.Four deformational events can be characterized within Ihc Tinaroo Area. Close to Ihe Tinaroo Batholith D1 and D2, arc so strongly developed that they disrupl the continuily of Ihe original Iithological layering. In the aureole region, D1 is strongly overprinted and its original fabric intensity is obscured, but both D2 and D3 display a mappable decrease in intensity away from the granite margin. These three deformations occurred during Carboniferous or early Permian time. D4 is later and only patchily developed.The broad, moderate pressure metamorphic aureole surrounding the Tinaroo Batholith is a typical of the CairnsCooktown group of Permo-Carboniferous granitoids. which usually develop narrow, lower pressure contact aureoles. Two periods of metamorphism are distinguishable. The first reached peak temperatures somewhat greater than 520°C, the second temperatures around 620-630° C immediately adjacent to the granite contact.Several cale-silicate lenses containing scattered scheelite mineralization occur within the area. Scheelite appears to have crystallized at the same time as the cale-silicate minerals, its appearance coinciding with the intrusion of the Tinaroo Batholith. Unlike many "skarn-type" scheelite deposits, the scheelite-bearing cale-silicates are Fe-poor, with no positive correlation between total Fe and W.

Jan 1, 1982

By J. I. Paige

As part of a continuing effort to develop technology that maximizes mineral and metal recovery from domestic resources, the Bureau of Mines investigated a method to totally utilize copper converter slags without recycling them back through the matte smelting furnace. The research was directed toward (1) recovering the contained copper in converting slags by producing a recyclable copper-iron matte, (2) carbothermically reducing the slags to recover the iron, and (3) producing slag wool from the depleted slags. This report deals with the reduction of three industrial converting slags, containing 2.0 to 7.3 wt-pct Cu, in an 800-kVA electric arc furnace to produce a recyclable copper-iron matte. The addition of sufficient iron pyrite to provide 29 to 113 pct of the stoichiometric sulfur (based on producing 40-pct-Cu matte) produced a recyclable matte (36 to 61 pct Cu) at an energy consumption of 520 to 700 kWh per ton of solid material charged. The expected energy saving for treating molten slag in an electric furnace (5-to 9-MVA range) is about 400 kWh per ton of molten slag treated.

Jan 1, 1982

By J-S Han, J-M Yao

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Shagou deposit is located along NE-trending faults within the high-grade metamorphic basement of the Xiong’er Terrane in the Qinling orogenic belt. It is a large Ag-Pb-Zn deposit hosted in the Taihua Supergroup and has proven reserves of 1.54 Mt of ore with grades of 767 g/t Ag, 13.24 per cent Pb and 4.31 per cent Zn. The hydrothermal ore-forming process can be divided into early quartz-pyrite, middle quartz-polymetallic sulfides and late quartz-carbonate stages. Four types of fluid inclusions (ie pure carbonic, carbonic, pure aqueous and aqueous) can be distinguished in quartz. Fluid inclusion, hydrogen, oxygen and sulfur isotope systematics indicate that the ore-forming fluids are initially deeply sourced metamorphic water with meteoric water gradually mixed in the later stages. Sulfur isotope data show that the ore-forming fluids originated from both the Taihua Supergroup and the sedimentary successions of the Guandaokou and Luanchuan Groups (CSC) located to the south of the Machaoying Fault. A genetic model of the Shagou deposit is proposed as follows: CSC subducted northward along the Machaoying Fault beneath the Xiong’er Terrane during the Mesozoic collision between the North China Craton and South China Block. Subsequent dehydration resulted in the devolatilisation of fluids rich in CO2. These fluids migrated upwards, reacted with the Taihua Supergroup and formed the Shagou deposit.CITATION:Han, J-S, Yao, J-M and Chen, H, 2015. Fluid inclusion and isotopic constraints on the mineralisation of the Shagou Ag-Pb-Zn deposit, Henan Province, China , in Proceedings PACRIM 2015 Congress, pp 615–618 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R. L. Kidd, T. H. Miller

"INTRODUCTION This paper is the seventh of a series of yearly reviews started in 1921 and pre¬sents information gathered in a cooperative investigation undertaken by the United States Bureau of Mines and the University of Utah. It is the purpose of this report to make available flotation—reagent consumption data and other milling information in such a manner as to be of value to the milling industry and to the manufacturer of flotation reagents.These data have been compiled from a survey of about 300 concentration plants in the United States. Much additional information has been obtained from the various offices of the United States Bureau of Mines. Many of the plants covered in the survey made complete reports of their operations, but others were apparently unable to supply this information in sufficient detail to meet the requirements of this report. As a result, some sections of the report are more complete than others. In general, however, the mill reports were much more complete than in previous years, and for the first time it has been possible to calculate average mill recoveries in the treatment of certain classes of ores. As in the past, every effort has been made to conceal individual plant operations.ACKNOWLEDGMENTSIt is realized that the publication of this information is possible only through the assistance of the mill operators, and the authors wish to express their appreciation of this cooperation. Thanks are also due the various field offices of the United States Bureau of Mines, division of mineral statistics, for assistance in collecting this information."

Aug 1, 1931

By E. Stoetzer

In all known deep mixing processes the existing soil is mixed with self hardening slurry by mixing tools that rotate about a vertical axis (augers, mixing paddles). Wall panels are constructed using sets of multiple mixing tools combined into a single unit. These techniques have been developed on the principle of the rotary drilling technology. In contrast, the new Cutter Soil Mixing or CSM technique is derived from the cutter technology. The soil is loosened and broken down by cutter wheels, then mixed in-situ by the rotating cutter wheels with the self-hardening slurry - introduced into the ground between the two wheels - to form a soil-slurry mortar. The main area of application lies in the construction of cut-off and retaining walls.

Jan 1, 2006

By Axel Nitschke, Josef Arnold

Bochum’s Underground Lot 306 was characterised by a confined site and unique tunnelling methods. A highly mechanized construction concept was developed to achieve high progress rates. Bespoke backup systems for muck disposal and material supply were used. For the first time in suburban tunnelling, wet shotcrete, batched onsite, was applied. A three-storey underground car park had to be undermined with only1.5 m of overburden and had to be lifted several times by “compensation grout in.” An existing operational two-lane metro tunnel was enlarged without any major impact on train operation.

Jan 1, 2005

By C. Laughton

Construction of a Deep Underground Science and Engineering Laboratory(DUSEL) is proposed under the auspices of the US National Science Foundation(NSF). DUSEL will provide scientists and engineers with a research facility capable of supporting a broad spectrum of fundamental and applied research deep in the earth’s crust. Research partners are physicists, biologists and geoscientists. DUSEL research calls for the construction of a network of shafts, tunnels and caverns that will provide laboratory facilities at depths of up to approximately 2 kilometers. The Project is still in the planning stages but, the initial experimental program is taking shape and conceptual designs have already been developed at two hard rock mine sites. This paper discusses the overall program and key engineering tasks being developed to support the construction of deep, large-span caverns. These caverns will house a new generation of physics experiments. As currently scoped, the experiments call for the excavation of permanent caverns with spans of up to 60 meters, sited at depths in excess of a kilometer.

Jan 1, 2007