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By George F. Swindle

This paper discusses a composite of two coal reserve studies, each of which made use of a computer-based modeling system to assist in an evaluation of multi-seam deposits. The model permitted simultaneous consideration of seam thickness, seam structure, overburden thickness, over-burden ratio, and quality parameters for sulphur content, ash content, BTU values and the EPA Compliance index. The model is designed for use by a non-programmer, geologist or mining engineer. It enables the user, from a computer terminal in his office, to specify constraints (for example maximum um sulphur and maximum- ash content, minimum seam thickness and minimum BTU rating), and produces a report showing the volume, quality and location of that part of the total in place deposit satisfying all the constraints.

Jan 1, 1983

By Luke Clarkson, David Williams

The intent of this paper is to provide overview context to allow broader understanding of conventional tailings dam failure mechanisms. The research leverages global knowledge, experience, and data collection and interpretation for the safe and controlled management of the geotechnical stability of a tailings storage facility. The motivation for this review is to facilitate transparent access to tailings dam background and understanding. This paper addresses the core understanding of geotechnical failure mechanisms, and how these eventuate to instability and failure of tailings dam structures. This research focuses on foundation failure, internal erosion and piping, overtopping, seepage, seismicity, and slope instability and provides insight into what factors contribute to failure, how failure progresses due to such failure, anticipating and monitoring for the aforementioned failure modes, and designing to mitigate their risk.

Feb 15, 2021

By M P. Simpson, J L. Mauk

The Golden Cross, low-sulfidation, epithermal deposit shows a number of features that are directly or indirectly related to boiling hydrothermal fluids. Occurrences of lattice calcite and their quartz pseudomorph equivalents in veins, and occurrences of adularia in veins and in the surrounding altered rocks in the vicinity of ore, are both direct evidence of deposition in the presence of boiling hydrothermal fluids. Loss of carbon dioxide causes calcite deposition (platy variety) near the level of first boiling, while adularia deposits due to the attendant pH increase along the cooling flow path. Indirect evidence of boiling include crustiform-colloform quartz banding, late massive calcite veins, clay-carbonate alteration in the shallow and peripheral parts of the ore zone, and the restricted vertical interval of precious metal mineralisation. The colloform quartz banding strongly resembles the banding in amorphous silica deposits found in geothermal surface pipes. This implies that fluids ascending the Empire Vein structure were saturated in amorphous silica. If so, then they must have undergone phase separation, which initiated at considerable depth (e.g. =1000 m) and very hot temperatures (e.g. =300¦C). On the basis of stable isotope data, late massive calcite veins appear to have deposited from CO2-rich steam-heated waters. Calcite deposited along heating paths as these waters descended into the upflow zone during late stage collapse of the hydrothermal plume. In active systems, such steam heated waters form by deep boiling. The high CO2 contents of these waters promote hydrolytic alteration and the formation of clay-carbonate alteration. Reaction path modelling using CHILLER and a deep, Broadlands-Ohaaki water as an analogue, shows that minerals deposit along boiling flow paths over discrete spatial intervals. Calcite and adularia deposit near the site of first boiling, followed by gold and then by amorphous silica. For deep boiling starting at 300¦C, these minerals deposit over a path length that exceeds 1000 m. The distribution of banded quartz and gold at Golden Cross are consistent with such a boiling model. However, the elevation of first boiling must have fluctuated over 500 m to account for the coincidence of lattice quartz (pseudomorphs of platy calcite) and adularia, crustiform-colloform silica and gold over distances of a few centimeters in veins. We deduce that a downward propagating boiling front and expansion of two-phase flashing in a flowing water column occurred during episodes of high vertical permeability and fluid flux in the Empire vein structure.

Jan 1, 2000

GENERAL CONTRACTOR: ALEXANDER CONSTRUCTORS, INC. STRUCTURAL ENGINEER: CAGLEY & ASSOCIATES, INC. GEOTECHNICAL ENGINEER: F.T. KITLINSKI & ASSOCIATES, INC. PILE FOUNDATION CONTRACTOR: L.G. BARCUS AND SONS, INC. PROJECT PROFILE: 108-10 in. diameter AugerPiles installed to an approximate depth of 32 ft. Piles were installed through Stiff Clayey Fill and Medium-Dense Sands to Decomposed Shale. Piles were drilled to a refusal criteria of 1 ft. / 3 min. Piles were installed using a Barcus Mantis AugerPile rig which is large enough to install piles 25 to 50 ft. long outdoors. The Mantis is also ideal for indoor and low overhead installations. On top of being extremely versatile, the Mantis is also very economical to mobilize. The existing structure is supported on H-Piles. The AugerPiles were furnished and installed for less than the material price of the H-Piles. Design loads were under 40 tons which eliminated the need for a load test. AugerPiles were selected for minimal vibration, limited noise, and economy.

Jan 1, 2001

By Mike Neill, O&apos

? Bypass soft soils near the surface ? Resist uplift loads ? Resist lateral loads ? Bypass scourable soils ? Bypass liquefyable soils ? Mitigate movement of expansive or frozen soils ? "Tune" foundations for vibrating machinery

Jan 1, 1998

By R. W. Mei, R. A. Strombom, D. J. Moore

"Heat-shrinkable cable accessories are solving problems in the mining industry. This paper describes a range of products used by the industry, including low-voltage splices, high-voltage splices to 8.7 k V, cable repair sleeves, mining cable terminations used on system voltages up to 25 kV and motor connection kits up to 8 k V. Technical procedures and designs are illustrated.IntroductionThe development of high-performance heat-shrinkable materials slightly over 20 years ago proved to be one of the major technological breakthroughs in power cable accessories. Heat-shrinkable products were introduced initially for use as low-volt age cable accessories in the aircraft and electronics industry. A program of continuous development and product introduction now enables the manufacturer to offer a broad range of products for mining, industrial and utility electrical systems.With the advent of atomic energy, an important discovery was made-exposure of some plastic materials to high-energy electrons can cause the permanent crosslinking, or intermolecular joining, of adjacent molecules. Once the material has been crosslinked, it will not melt or flow at any temperature.The unique properties of heat-shrinkable products also result from the exposure of special thermoplastic formulations to high-energy electrons. Because of crosslinking, these products have perfect elastic memory. The heat-shrinkable products are supplied in expanded condition. When heated, they will shrink and tightly cover the object over which they have been placed. 'The functional and operating demands of mine cable accessories exceeded the classic electronic applications of heat shrinkable materials. These demands required a very sophisticated program to develop materials and adhesive systems that could endure the operational environment associated with the mining industry,Ease of assembly, low installed cost and operational reliability are among the main reasons for the acceptance of heat-shrinkable mine cable accessories in electrically powered mines. For over a decade, these systems have been demonstrating proven performance."

Jan 1, 1980

By S. q. Honingh, G. Van Weert

Currently produced zinc-enriched blast furnace dust is stored on site at CORUS IJmuiden. To end this practise, a research program was started in 1996. Four technologies were studied: oxidative autoclave leaching in a chloride medium, fluid bed pyrohydrochloridisation (pyrohydrolysis) to yield lead-zinc-free (hematite) calcine, EAF (plasma) smelting/zinc fuming, and incorporation of the dust in 'iron foundry cupola charges. All aim to remove zinc and lead, recycle the iron residue internally, and produce a saleable zinc-lead product.

Jan 1, 2000

By C. Özgen Karacan

The formation of the gas emission zone in longwall mining and the potential amount of gas in this zone are factors of local geology and spatial variability within this geology. Therefore, geostatistical methods can be used for modeling and prediction of gas amounts and for assessing its uncertainty in the gas emission zone of longwall mines. This study used core data obtained from 64 exploration boreholes drilled from the surface to the bottom of the Pittsburgh coal seam in a mining district in the Northern Appalachian basin. After identifying important coal layers for the gas emission zone, semivariogram modeling was conducted for different coal seams to define the distribution and continuity of various attributes. Sequential simulations were performed for stochastic assessment of these attributes to calculate gas-in-place (GIP) in each coal seam. GIP calculations for coals of various gas emissions zones were combined and ranked for their cumulative distribution function to find GIP in the caved zone and in the fractured zone at the 5%, 50%, and 95% quantiles. Fifty percent quantile results were later used to isolate a panel from the whole area and create a mosaic representation corresponding to the daily advance rate of the longwall face. This approach helped to estimate the daily emissions of this panel from the caved zone and from the fractured zone. Results showed that gas-in-place in the Pittsburgh coal seam, in the caved zone, and in the fractured zone showed spatial correlations that could be modeled and estimated using geostatistical methods. This study showed that gas-in- place volumes in the study area may be as high as 12.3 Bscf and as much as 3.5 MMscf per acre of mining.

Jan 1, 2012

By Masayuki Ishikawa

In a radio frequency and optoelectoronic device packaging, Gold-Tin (Au-20 wt% Sn eutectic) solder is used widely due to the excellent electrical and thermal conductivity, high strength, and negligible creep characteristic under repetitive thermal cycling. With the recent lead-free movement, Gold-Tin solder is recognized as an alternative material for high temperature Lead-Tin solder. Generally, Gold-Tin solder is supplied in the forms such as ribbons, pellets, and ring frames. However, these forms must be set-up accurately on the joint area to press chips in bonding, therefore, it is difficult for these forms to satisfy the recent requirements for the down sizing in the connection areas. On the other hand, Au-20 wt% Sn solder paste can be applied flexibly to various supplying methods, such as printing, dispensing system and pin transcript. These methods also make it possible to reduce the production cost. However, in the case of using the solder paste, the void issue is one of the most undesirable problems. The void causes the degradation of the characteristics such as the bond strength, electrical characteristic and thermal conductivity. We have been intensifying the development of the void free paste, and have achieved void reduction by optimizing the powder size, the flux composition and the reflow condition.

Oct 1, 2003

By Bill Kyslinger

In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Boart Longyear Poland and KGHM, J. H. Fletcher & Company was tasked to design and manufacture a single-boom, single operator drill module for installation of 1.2 meter expansion bolt in a 1.6 meter height mine. The objective was to produce a machine to provide ergonomic improvements for the operator while working in the mine environment. This dictated the requirement for a small easily controlled, maintenance friendly design with a remote operator?s control station. The selected design method was to use starter and finisher drill steels. This combination, requiring a number of mechanized machine motions, provides the ability to drill the required depth in the specified mine height. To accomplish the task from a remote location, a conscious decision was made to employ current technology in the form of small pressure compensated hydraulics and electronic controls. The result of the design method is a modular assembly with each sub-component designed to be replaceable and adjustable independently from other machine components. The low profile remote roof bolting module is made up of six major sub-components. Each major component is painted a different color to help the operator make the visual connection from the drill module to the operator?s control/display monitor. The Stabilizer (White) secures the module between the mine top and floor. The Drillhead (Orange) produces the drilling rotation and torque but also must slide out of position to allow the machine to manipulate the drill consumables. The Drill Steel Carousel (Blue) holds and indexes the starter and finisher steel from position to position. The Manipulator Arm (Green) moves and guides the drill steels and drill consumables from position to position during installation. The Roof Reference Guide (Yellow) locates the mine roof and guides the drill steels and drill consumables into position. The Linear Bolt Carousel (Purple) holds the drill consumables. The low profile remote roof bolting module allows the operator to drill and install a roof bolt manually or automatically with the push of a button. This design substantially reduces the operator?s exposure in the mine environment, as well as inherent pinch points and rotary hazards. Positioning the operator safely in the confines of the air conditioned cab.

Jan 1, 2006

By Harry E. Brownlow

The United States Bureau of Mines contracted Norecol to prepare a report identifying the regulatory processes associated with metal mine development in British Columbia using the Snip Mine as a case study. The intent of this study is to assist industry and regulatory agencies in developing understanding as to differences in objectives, perspectives and operating methods. The case study will be incorporated into a larger report summarizing the comparative advantages and disadvantages of metal mine permitting in British Columbia and Alaska. The purpose of the report is to identify the development schedule and permitting process at Snip which will assist the U.S. Bureau of Mines in suggesting improvements in environmental review and permitting processes for mine developments. The report provides an abstract of the environmental assessment review processes in Canada and the Mine Development Review Process in British Columbia and provides an understanding of the linkages between policy, legislation, and environmental review.

Jan 1, 1992

Queensland?s underground coal industry, as a whole, has arguably the best gas monitoring systems in the world. Each mine utilizes real time, tube bundle and onsite ultra fast gas chromatograph systems. Queensland?s mining legislation has specific requirements for mine gas monitoring but there is no requirement for all three techniques. Industry has however identified the need for all three and adopted this as a standard, resulting in over sixty thousand gas results collected each day. Automated monitoring systems are programmed to alarm for gas concentrations, gas ratios and explosibility. These alarms are then used to initiate predetermined actions to take control of the situation and prevent the compromise of safety to workers and the loss of resources. Dedicated software packages have been developed to assist in the interpretation of the large volume of results generated. The real time systems are used for real time warning, essential for incidents such as belt fires. Tube bundle systems suit long term trending used for identification of the onset of spontaneous combustion or for the determination of explosibility during the routine sealing of worked areas. Gas chromatograph analysis is used to provide a complete analysis and provides results for hydrogen and ethylene, key gases used in the assessment of spontaneous combustion. It is also crucial during significant spontaneous combustion events and coal fires to use gas chromatography to determine the explosibility status of the underground atmosphere otherwise the severity of the situation is likely to be under estimated. This paper outlines the need for all three techniques for assessing the underground status and outlines advantages and disadvantages of each.

Jan 1, 2009

By Donald L. Katz

FIFTEEN years ago Dr. Manning published a paper in "Petroleum Development and Technology" on '.Fundamental Research Relating to Petroleum." He tabulated for several industries "the proportion of their present success which can be fairly attributed to the application of information and processes obtained by scientific research," giving petroleum a score of 7 compared to 100 for the electrical and coal-tar industries. Today the petroleum industry as a whole and the producing groups both have raised their score beyond the majority and are climbing toward the top. Present practices are being developed both by fundamental research and the application of the research method in field operation.

Jan 1, 1941

By R. T. Jones

Base metals and platinum group metals can be collected in metallic alloy form, via a wide variety of smelting processes. The recovery, or degree of collection, of the valuable metals is a function of the extent of reduction in the furnace, which, in turn, is indicated by the fraction of iron present in the feed materials that report to the alloy. An equation has been developed that relates the recovery of various metals (such as Ni, Co, Cr, and PGMs) to the recovery of Fe. This recovery equation (for each metal) is characterized by a single parameter (K?) that can either be empirically fitted to the data, or expressed in terms of the equilibrium constant and the ratios of the activity coefficients involved. Data from a number of varied DC arc furnace campaigns are presented to illustrate this behaviour.

Jan 1, 2009

By S. Hunt, D. de Vries

Kansanshi Copper Smelter began operation in March 2015. The smelter features a single Isasmelt furnace for smelting, one 6-in-line electric furnace for matte-settling and slag-cleaning duties, four Peirce- Smith converters and two rotary anode furnaces. A 1,450 t/day oxygen plant and a 4,085 t/day sulphuric acid plant are included in the smelter operations. This paper gives an overview of the operational performance to date with summary data for each smelter section. Challenges such as an unforeseen refractory failure in the Isasmelt furnace in 2016 are discussed. Design improvements around the electric furnace are mentioned. Plans for potential future improvements are put into context. A consistent focus on operations, maintenance and continuous improvement has seen the smelter easily achieve its nameplate capacity of 1.2 million tonnes per annum of copper concentrate throughput. The smelter now operates consistently at a concentrate throughput rate of 1.38 million tonnes per annum of copper concentrate. INTRODUCTION The smelter was commissioned in March 2015. Design and commissioning of the smelter have been discussed by de Vries, Hunt, Hanschar and Louie (2016). The smelter rapidly ramped up to achieve nameplate production (1.2 million tonnes per year concentrate) and in 2018 operated consistently at the rate of 1.38 million tonnes per year concentrate. This paper presents major operational data for each section of the plant and describes significant events and improvements during the first four years of operation. The smelter flowsheet is shown in Figure 1.

Jan 1, 2019

Rock mass classification systems are extensively used in rock engineering design work, and mine design is no exception. Among the systems most widely used for mining-related design work are the NGI 0-system (Barton et al., 1974), the RMR system (Bieniawski, 1976), the MRMR system (Laubscher and Taylor, 1976) and, more recently, the GSI system (Hoek et al., 1998). Classifying the rock mass is widely seen as being the fieldwork required to characterize the rock mass and enable the application of empirical design methods associated with the different classification systems. This paper argues that it is fundamentally important to recognize the distinction between rock mass characterization and rock mass classification. These two processes should, in most cases, be separated from each other. Rock mass characterization should be used to determine the intrinsic properties of the rock mass independently of the application; i.e. independent from the infrastructure to be designed, the size, shape, and orientation of the excavation(s) or pillar(s), etc. Rock mass characterization should also be compatible with most classification systems and empirical design methods to be used. Rock mass characterization is the background fieldwork required to perform rock mass classification and/or engineering design work. Rock mass classification is the subsequent step to the characterization, and an integral part of the design process. Parameters that vary according to the design, such as the relative orientation of geological structures compared to the opening or the mine-induced stresses, should be calculated as part of the rock mass classification and design process, rather than during the rock mass characterization process. The failure to distinguish between rock mass characterization and rock mass classification can lead to major design errors and poor results.

Jan 1, 2012

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, Mexico, 150 km (95 miles) southwest of Ciudad Juarez (Fig.1). The ore deposit was discovered in 1979 and was placed in production in 1992. The production rate is about 2.4 kt/d (2650 stpd) from an ore reserve of 8.5 Mt (9.3 million st). Grades currently average about 8% zinc, 0.5% lead, 0.2% copper and 50 g/t (1.46 oz/st) silver. Substantial inflows of water into the underground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark is a joint venture with 90% participation by Minas Penoles, SA de CR of Mexico City and 10% participation by Promociones Industriales Banamex, S A de C V (PIB S A) of Mexico City. Anew company, Minera Bismark, SA de CV was formed to operate the property. Cyprus Minerals was a 40% participant in the joint venture but, in early 1993, sold its share to Minas Penoles. The Bismark Mine is one of the largest new underground mining projects built in Mexico during the last 10 years. It is the country's fifth largest underground metal mine and provides about 1 % of the world's zinc supply at about 50 t/a (55,000 stpy). Bismark is a trackless operation with overall productivities of 7.6 t/manshift (8.4 st/manshift). The 2.4-kt/d (2650-stpd) concentrator started up in March 1992.

Jan 1, 1994

By Letícia Pegoraro Leal

O mercado mundial está se desenvolvendo continuamente em todos os segmentos com a finalidade de melhorar a qualidade e diminuir os custos. O aperfeiçoamento e a criação de novas técnicas de soldagem são responsáveis por conservar as propriedades mecânicas e realizar as soldas com um menor número de defeitos. Este trabalho apresenta o processo de soldagem por fricção com pino consumível, conhecido como FHPP (Friction Hydro Pillar Process) em pino AISI 4340 e chapa AISI 4140. Como toda nova técnica é importante conhecer os parâmetros que serão utilizados no processo. Compreender o efeito da velocidade de rotação, força axial e de forjamento, consumo do pino e taxa de carregamento são necessários para avaliar sua influência na microestrutura da solda. Desta forma, no presente estudo, após a soldagem foram realizadas metalografias, a fim de analisar defeitos macro e microestruturais. Por fim, verificou-se significativa influência dos parâmetros de processo no comportamento metalúrgico da região soldada.

Aug 8, 2018

By William J. Campbell

This report describes a Bureau of Mines study undertaken to determine the applications and limitations of solution techniques as a general method of fluorescent X-ray spectrographic analysis. Systematic errors due to variations in particle size, surface preparation, and sample inhomogeneity are eliminated by the use of solutions. The range of applicability of fluorescent X-ray spectrography is increased in two ways: (1) Samples in the form of wire, filings, turnings, etc., can be analyzed as solutions, and (2) samples submitted as solutions can be analyzed as received 0 The lower limit of detectability varies from 0.14 gram per liter for sulfur, atomic number 16, to 0.0015 gram per liter for strontium, atomic number 38. Most elements have limits of detectability between 0.02 and 0.002 gram per liter.

Jan 1, 1959

By Mel Febesh

Working in New York City has become the graveyard of many Foundation Contractors. Varying subsurface conditions require Foundation Contractors to be aware of the conditions at each particular site and have the knowledge and equipment to successfully complete the project. Looking back, we can see that many of the methods and much of the equipment that were commonly used in the past have been replaced with newer methods and equipment, but sometimes the old methods prove to be the most reliable. This paper will describe examples of varying conditions and construction methods in sites that are close to each other. It will also show different construction problems that are encountered when working adjacent to existing subway structures, when excavating below the foundations of adjacent structures and when ground water is encountered.

Jan 1, 2000