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By William H. Lewis

Energy Research Corp., under contract to the Bureau of Mines, has developed a new miners' caplamp battery. The new battery is based on nickel-cadmium technology and offers significant improvements in performance with reduced size and weight when compared to the conventional lead-acid battery presently in use. This report describes the design and fabrication of the nickel-cadmium battery, which utilizes a roll-bonded electrode structure. The final battery design has a 15-A-h capacity in a 2-112-lb package, which is over 2 lb lighter than the present lead-acid caplamp battery.

Jan 1, 1983

By G. W. Jones

The results presented in this report deal with the elimination of explosion hazards of ether-oxygen mixtures by the addition of helium. The method is based upon the fact that every combustible gas, vapor, or dust will not burn or explode when the oxygen content of the mixture is reduced below certain definite values. These critical oxygen values are usually different for each combustible, varying with the percentage of the combustible present in the mixture and also with the inert gaseous material used to reduce the oxygen content of the mixture.

Jan 1, 1941

By Cathy Aimone-Martin, Caitlin Woznick, Brent Meins

This study is a continuation of previous work in which the responses of tall structures to close-in construction blasting at two rock excavation sites are evaluated. A total of eight buildings were instrumented to calculate blast-induced wall strains. Of these structures, five high-rise buildings measuring 166 ft (51 m) to 294 ft (90 m) in height (15 to 24 stories), were included for this study and compared with the results of previous studies that included one to three story residential structures and mid-rise structures (four to six stories). All five structures were built between 1908 and 1940 with interior walls comprising aged plaster. Three of the structures are designated Landmark, subject to a 0.5 in/s (12.7 mm/s) regulated peak particle velocity (PPV) limit. The regulated PPV limit for the two other structures was 2.0 in/s (50.8 mm/s). To date, a total of 450 close-in construction blasts have taken place over six months at the two adjacent projects, blasting three to six times per day at each site. Seismograph instrumentation included tri-axial geophones in the ground and bi-axial geophones (horizontal components only) mounted on structure exteriors at the corners closest to blasting. Peak global wall tensile strains were calculated from time-correlated differential structure displacements in two horizontal directions as measured by upper and lower geophones mounted near the roof and at street levels. Wall strains were correlated with ground excitations to establish a stiffness factor for each structure defined as the upper bound linear regression slope for strain as a function of ground displacement. In addition, a structure-specific regression best-fit function was established to relate horizontal components of displacement to velocity. These two functions were used to determine the maximum ground motion velocity for a desired limit placed on wall strain. A 25 ?-strain limit was suggested for both projects to protect interior plaster walls. To date, global wall strains have not exceeded 0.53 ?-strains (or 47 times the project limit) for peak particle velocities up to 3.49 in/s (88.6 mm/s). This demonstrates the low strain response of tall structures to ground velocities well above regulated limits. The stiffness factor computed for the most flexible high-rise building was 688 in-1 (17475 mm-1). In comparison, stiffness factors for the most flexible residential and mid-rise structures previously studied were 8651 in-1 (219735 mm-1) and 4387 in-1 (111430 mm-1), respectively. Based on a large number of measurements made at these study structures, the maximum horizontal ground velocity needed to achieve 25 ?-strains in walls ranged from 36 in/s (914 mm/s) to 192 in/s (4877 mm/s) because of the high stiffness of these buildings. Such high amplitudes of ground vibrations can never be safely achieved during close-in blasting in urban environments. These excessive values stand to show how unfounded the current limits of 0.5 in/s (12.7 mm/s) and 2.0 in/s (50.8 mm/s) are when applied to massive, tall structures. This study demonstrated that upper structure motions are highly attenuated from the lower (street-level) motions because of the long travel distances up the buildings. High-rise structures are far stiffer than mid-rise and residential structures and can withstand ground vibration amplitudes far greater than the currently enforced blasting limits in New York City.

Jan 1, 2015

By G. W. Jones

The results presented in this report deal with the elimination of explosion hazards of ether-oxygen mixtures by the addition of helium. The method is based upon the fact that every combustible gas, vapor, or dust will not burn or explode when the oxygen content of the mixture is reduced below certain definite values. These critical oxygen values are usually different for each combustible, varying with the percentage of the combustible present in the mixture and also with the inert gaseous material used to reduce the oxygen content of the mixture.

Jan 1, 1941

By M. A. Elliott

The technology of gasifying coal to produce synthesis and pipeline gas has advanced significantly in the Past 20 to 30 years. This period has seen the extensive use of oxygen in coal gasification, the development of suspension gasification processes and fluidized-bed gasifiers, the operation of various gasification processes at elevated pressures, and operation of gasifiers under slagging conditions. These developments are discussed, and their application to commercial and pilot plant gasifiers is reviewed. Typical processes for synthesis gas production are described, and operating results are compared. Pipeline or high-Btu gas may be produced from coal either by catalytic conversion of synthesis gas to methane, or by the direct reaction of coal with hydrogen (hydrogasification) to produce a methane-rich gas. Neither of these methods has been applied commercially, but developments pertaining to each of them are reviewed, and general processing schemes are discussed. The use of coal as a raw material for manufacturing gas has a long and distinguished history. In fact, the gas industry began in the early 1800's when William Murdock demonstrated that it was feasible to produce and distribute gas made by retorting coal. Coal was used exclusively for gas manufacture until the middle of the 19th centruy, when Lowe invented the carbureted water gas process. In that process, coke was one of the raw materials used, so coal was still an important factor in gas manufacture. However the availability and relatively low cost of natural gas in the United States, and its widespread distribution by long-distance pipelines in recent years, has virtually eliminated the use of coal as a raw material for gas manufacture in this country. It should not be inferred from the foregoing that the technology of coal gasification has remained static in the United States and abroad. In fact, in the past two decades many new concepts have been developed in both the science and the technology of gasification. This progress has been a result of the considerable expansion in research on the fundamental chemistry and physics of gasification reactions, and in development work on gasification processes. This expansion in effort stems in part from increased interest in the use of gas as a raw material for the synthesis of chemicals and liquid fuels, and in part from the need to develop methods for gasifying coal and other solid fossil fuels to ensure a long-range supply of energy in the form of gaseous fuel. In these uses of gas, synthesis gas, a mixture of hydrogen and carbon monoxide in various proportions, is the starting material. It may be converted catalytically to gaseous and liquid hydrocarbons and other chemicals, or to hydrogen for use in hydrogenation or reduction reactions. Since coal is our most abundant fossil fuel, it is inevitable that one day it will regain its prominence as a raw material for gas manufacture. It is of interest, therefore, to consider the present status of gasification technology, directing attention particularly to advances made in recent years. Inasmuch as many comprehensive treatises l-3 and review4-7 of gasification technology are available, no attempt will be made in the present review to cover all processes in detail. Instead, the discussion will be concerned chiefly with typical processes embodying the advances that are most likely to be generally applied. ADVANCES IN GASIFICATION TECHNOLOGY For purposes of this discussion the starting point will be the conventional processes that were used for many years for the complete gasification of coal. These were: 1) carbonization in coke ovens followed by gasification of coke with air and steam in cyclic water-gas generators, and 2) fixed-bed air-blown producers. Both of these methods have obvious deficiencies when we consider that the ideal complete gasification process would be a single-stage, continuous

Jan 1, 1961

By L. M. Scovell

The Internet and its related technologies will radically change the way that mines manage and control their maintenance, repair, and operating supply chains. The Internet is creating new distribution channels and offers new technology platforms with significant advantages over more traditional methods. Mines will have to re-evaluate both the strategies and the tactics employed in these areas. Mines will use e-commerce to integrate their maintenance, repair, and operating supply chains. The integration will extend beyond traditional trading partners to a worldwide network of communities with similar interests and goals. The changes will transform the way mines operate, lower mining costs, and thereby increase their chances of success in an increasingly competitive environment.

Jan 1, 2000

By AIME AIME

MANY interesting papers, opportunity of seeing o1d friends, and an exposition showing all that is latest in equipment, all were factors in bringing a large crowd to Detroit during "Metal Week," October 2-6. The Institute's Iron and Steel and Institute of Metals Divisions held technical sessions at the Statler Hotel on October 4 and 5, and that hotel was also headquarters for the American Society for Steel Treating and the American Society of Mechanical Engineers, both of which also had technical sessions. The American Welding Society and the Wire Association met at the Book-Cadillac Hotel, and the exposition was staged at Convention Hall, out Woodward Avenue. All in all it was a big week for men interested in metal working. One of them stated to your reporter on the train en route to Detroit that this was the one convention that he never missed, and doubtless others felt the same way about it.

Jan 1, 1933

By Paul Downing

A typical day for a blasting company includes what seems to be an infinite list of tasks dealing with numbers. Whether determining the exact amount of explosives material in inventory, the number of holes in the shot, the exact distance from the blast site to the nearest exposure, or the capacity of bulk hoppers, the accuracy of numbers is key to ensuring the safety of the public, property and personnel.

Jan 1, 2008

By A. W. Dougall, T. M. Mmola

"SynopsisThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs) – which are those areas of performance that are reflected explicitly or implicitly in the vision and strategies of an organization and reflect the critical success factors of the organization. This paper is a review of key performance areas in the southern African mining delivery environment. The KPAs discussed in this paper have been identified by comparing KPAs of the several mining houses engaged in surface mining operations in southern Africa and then extracting those KPAs that are common to most of them. Although the authors support the view that each organization should develop KPAs to specifically fit its needs, the study reveals that five KPAs – safety and health, costs, product quality, fleet management, and delivery should form a default list that covers the key areas that any organization should consider when choosing KPAs. KPIs are those subsets of KPAs that we measure in order to manage KPAs.IntroductionThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs), which are ‘those areas of performance that are reflected explicitly or implicitly in the vision and strategies of the organization’ (Barker, 1997). The terms KPA and KPI (key performance indicator) are often used interchangeably – whether correctly or erroneously is debatable. KPIs are ‘quantifiable measurements, agreed to beforehand, that reflect the critical success factors of an organization’ (O’Neill, 2007). Each KPA probably has multiple KPIs associated with it."

Jan 1, 2015

By J A. Braithwaite

Social licence to operate is not a new concept for the mining industry, referring to stakeholder approval or acceptance for the activities and impacts of a project, company or industry. It is intangible, dynamic and non-permanent, hence it needs to be earned and then maintained (Thomson and Boutilier, 2014). It has also been argued that social licence extends beyond building approval or acceptance, into engagement for long-term development (Owen and Kemp, 2012).There are many examples where stakeholder opposition – or withdrawal of social licence – have increased capital and operating costs, extended schedules and impacted reputation. At its extreme, the withdrawal of social licence to operate can also contribute to or be the catalyst for mine closure.The key benefit of obtaining a social licence is a reduction of risk. Stakeholder support and advocacy, as well as the implementation of social performance programs that contribute to social licence, can be beneficial in terms of schedule, costs and other benefits.While decisions to close a mine are generally driven by resource availability or economic conditions, the social, economic and environmental legacy remaining post-closure is of importance to many stakeholders. With a number of significant mines now approaching closure within Australia, we are seeing heightened community concern about the economic and social impact of mine closure and the success of land rehabilitation. So how does the concept of social licence to operate extend into the closure phase of the mining life cycle?CITATION:Braithwaite, J A, 2016. Social licence to close?, in Proceedings Life-of-Mine 2016 Conference, pp 176–179 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Steve Kral

As the current boom in the global mining industry rumbles on, mining companies have had to step up their efforts to replace mined reserves. Many of the majors are replacing and adding to their reserves and resources through acquisitions. This situation has allowed junior mining and exploration companies to do what they do best. They have been re-examining once uneconomic gold, copper and other metals properties with an eye to partnering with a major to develop them. And mines that have been closed for years due to poor economics are being given another look.

Jan 1, 2006

By Herty, C. H.

The effect of temperature on the physical properties of structural materials has been the subject of many investigations during the past decade. The literature on the effect of elevated temperatures. is voluminous, and during the last four years a great deal of experimental work has been carried out on the effect of low temperatures on the impact properties of steel. For many engineering purposes it is important to know the shock resistance of steels at low atmospheric temperatures, and with the ever-developing field of refrigeration and separation of materials at low temperatures, the normal limits of atmospheric temperature have been exceeded in practice. Iron and its alloys in the unnotched condition have a high impact strength at low temperatures, but in practice variations in type of notches result either from design or accidentally through scratches and surface or internal defects. A study of notched bar impact tests is, therefore, highly important to the engineer. A survey of the literature on low temperature impact testing indicates that chemical composition, heat treatment and method of testing have been the variables which have been considered in most previous work. In only a few instances has any mention of the steel- making method been mentioned and in these the comparison was between steel-making processes and not between steel-making methods on the same process. In view of the wide variations in impact properties at room temperature, in quench and strain ageing and in grain growth of steels of identical chemical composition, (by this is meant the usual five element analysis reported), it was felt

Jan 1, 1957

By V Dolmage

Copper Mountain is the third largest copper mine in British Columbia, and is now producing close to 20 million pounds of copper per year, with which is recovered also 4,000 ounces of gold and. 13,800 ounces of silver. After a long and checkered career, during which the ownership and management changed several times, this deposit finally came into the possession of the Granby Consolidated Mining, Smelting and Power Company in 1923. It was not, however, until the end of 1925 that the mine, under the management of Charles Bocking and C. H. Smith, was successfully placed on a basis of profitable production. It is a low-grade deposit of the contact-metamorphic type, with refractory ores consisting of chalcopyrite and bornite in a gangue of altered andesitic and basaltic breccia. The ore is concentrated to a product carrying over 30 percent copper, which is smelted in Tacoma. The deposit is 12 miles south of the town of Princeton, which is on the Kettle Valley railway, 150 miles east of Vancouver and 40 miles north of the International Boundary line. Princeton is served also by a branch of the Great Northern railway, which leads clown the Similkameen, Okanagan, and Columbia valleys. Copper Mountain mine and camp are connected to Princeton by a good mo tor road extending up Wolf Creek valley, while the haulage level of the mine, which emerges on the steep side of the Similkameen valley 1,000 feet below the camp, is connected with Princeton by a spur of the Kettle Valley railway leading up the Similkameen canyon and passing en route through Allenby, where the concentrator is situated.

Jan 1, 1929

CONTENTSIntroductionNorthern ExplorationDrive ConceptionGeneralDriving CrewDrive Cross Section and Track DetailsVentilation by Electrically Driven FanTemperatures and HumidityFan PerformanceRock Drill Carriage and Rock DrillsStandard Drilling RoundElectric Firing from Power MainsExplosives and DetonatorsCharging and FiringMechanical Loading and Electric HaulageOperating CycleStatisticalEquipmentAcknowledgementINTRODUCTION.The driving project described in :this paper is one of greater magnitude than usual for the Broken Hill field, and in the execution of the work a departure was made from long-established local practice by the introduction of mechanisation. The primary object of the drive is to provide sites for gaining information regarding the behaviour of the ore-bodies well beyond the limits of the present exposures.Due to thermal conditions, the major portion of the work was done on a six-hour shift basis, in contrast to the normal one of seven hours, with a five-day week.

Jan 1, 1946

By V. Arslan

The primary advantage of using oxalic acid is in the formation during leaching of soluble complexes that are both photo-chemically and microbiologically degradable. In this study, chemical leaching and bioleaching methods were used for quartz sand. Using the ANOVA-Yates test technique, the effects of solids rate, temperature and oxalic acid rate were investigated using chemical leaching experiments. Solids rate and temperature were effective parameters on the chemical leaching. After the tests, the removal of Fe2O3 increased to 97.02%. Finally, the iron content decreased from 0.315% Fe2O3 to 0.0094% Fe2O3 in the leached quartz sand. The effect of pulp density was investigated on the bioleaching experiments. The bioleaching of iron oxides by Aspergillus niger resulted in removal of 47.70% of the total iron in the quartz sand, and suggested that this strain has not a good ability to remove iron impurities from quartz sand in comparison with chemical leaching. The iron content decreased from 0.315% Fe2O3 to 0.164% Fe2O3 in the bioleached quartz sand.

Jan 1, 2009

By Kenneth E. Hay

Researchers from the U.S. Bureau of Mines conducted a field study to assess the safety of remotely controlled mobile roof supports (MRS) in a retreat pillar mining operation, Data were collected to provide the Mine Health and Safety Administration with criteria needed to develop guidelines for MRS use and to determine if precursors could be identified that would alert miners to imminent roof falls. Two test sites at which two different support methods-MRS's and posts were used and were monitored to obtain information on entry stability. Pressure transducers and string pots were installed on all four MRS's to obtain loading and displacement information. and roof bolt load cells. sonic probes, extensometers, and survey targets were installed in the surrounding entries to obtain information on ground behavior. Results showed a larger increase in roof bolt loading and roof movement when MRS's were used, especially in the intersection area. Roof bolt loads in the entries showed decreases in load when the MRS's were set and increases up to 11,1 kN (2,500 lbf) when the MRS's were unloaded. Unloading of one MRS in a pair did not significantly increase load on the other. MRS's I and 2 usually had the higher loads, with these loads increasing as the pillars on each side were being mined. MRS 3 normally had lower loads than I and 2: however, it also experienced some very high loads when in the last position near the pushout. MRS 4 usually had the lowest loads, primarily because it was located near the solid pillar that was not being mined.

Jan 1, 1995

By Todd M. Ruff

Current methods of inspecting wire rope for broken wires or excessive wear include visual inspection, physical measurements of rope diameter, and electromagnetic nondestructive testing (NDT). Visual inspection and physical measurement arc the least comprehensive methods. Electromagnetic NDT enables a more thorough assessment of the condition of a wire rope, but the repeatability, accuracy, and objectivity of this method can be improved. One means of achieving this goal is to use a computer to analyze the test data and determine the condition of the wire rope, including the presence of broken wires and corrosion, and the amount of wear. An off-the-shelf data acquisition and analysis system was tested in a U.S. Bureau of Mines laboratory using a continuous loop of wire rope containing fabricated flaws. The test rope was run through a commercially available NDT instrument. The output of the instrument, normally connected to a paper strip chart recorder, was digitized and analyzed with a personal computer. These initial tests were successful in showing that the use of a computer can improve current methods of NDT waveform collection and analysis.

Jan 1, 2010

A way back in 1851-2 an army of diggers had commenced the conquest, of the now famous goldfields of Australasia. At that time, and in the Colony of Victoria, more that 10,000 were camped on and around the slopes of the silurian ridges over which Ballarat East h'as been built. A wonderfully rich golden harvest was soon gathered from the alluvial found high on these slopes, and from runs (or gutters) which got their rise on them, and were traced down gullies into a broad valley. In due course it was ascertained that the valley carried a main gutter which represented the unity of the higher ones, and further explorations proved this gutter to have a westerly and then a southerly trend toward and under a basaltic plateau, on the top ofwhich Ballarat West and Sebastopol now stand. In the records of alluvial gold mining all the world over the Ballarat field can be classed amongst the richest. Gold in pieces the size of beans, in, stringy filigree bits, in dust and in solid lumps (the largest of which weighed more than 2,200 ozs.), was obtained in the comparatively shallow ground on the slopes; and speaking generally, great and uniform richness was met with along a belt of country on which, in a north and south line, the present quartz mines of Ballarat East are at work. It was noticed by the diggers that when the gutters crossed the upturned edges of the ,strata, the gold deposits in them were patchy, and that when they trended north and south on this beltthey carried rich deposits for longer distances. In time it was also noticf!d that a class of stringy, irregular shaped quartz occurrences, in a bottom of soft slates, in the, immediate vicinity of tpe g)ltter, meant greater richness, and (in the aIluvial) on the higher ground slabs of quartz would now and then be met with, in which strings and spongy masses of gold were found. As the shallow alluvial became worked out the diggers turned their attention to the quartz occurrences, and, now and again the striking of a flat make of a very golden nature would cause quite a stir in the local mining world.

By Donald A. Brobst

Barite, the sulfate of barium, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. The commercial deposits of barite may be classified into three major types. 1. Vein and cavity fillings that occur in rock fractures, along bedding planes, and in various solution structures. 2. Bedded deposits in which barite occurs as the principal mineral or cementing agent in stratiform bodies in sedimentary rocks. 3. Residual deposits occurring in unconsolidated material formed by the weathering of preexisting rocks. The geologic characteristics of each type of deposit are of fundamental importance to the successful search, development, and economic use of barite deposits.

Jan 1, 1980

By P. Share

As part of JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), high-resolution tiltmeters were installed during 2007 at Mponeng gold mine, South Africa, in an attempt to study and understand the risks posed by in-mine seismic events and to subsequently use the knowledge gained to mitigate these risks. In December 2007, an M2.2 event occurred at Mponeng and was detected by the tiltmeters installed. The tilt expected for the M2.2 event is modelled through the use of numerical and analytical tools and utilizing, as input parameters, characteristics of the event such as the rupture area, the amount of slip, elastic properties of the rock, the state of stress before the event occurred, and frictional parameters of the rupture. The calculated tilt values are correlated and compared with the recorded data, and are found to be of the same order. Certain input parameters, such as the initial rupture point, are further constrained by varying them, during modelling, until the calculated and observed tilt values are approximately equal. From modelling, it can be concluded that the rupture point had to be closer to the location of the tiltmeters. In addition, possible locations acting as source areas for the observed aftertilt are determined. Further modelling still needs to be done to quantify the effects of the tunnel close to the tiltmeters and plastic deformation of the rock mass. Keywords high-resolution tilt data, Mponeng gold mine, M 2.2 seismic event, analytical modeling, numerical modeling, rupture plane.

Oct 1, 2013