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By E. R. Maize

[In %-port of Invcstiptionn 7452 ,g dcniing with roof ~wet,ent in the Cmcibla r~ine, rof&apos;erence .,as m.da to the f~ct tiwt timker decny war, bsing studied at tho tine of writing. Thic napor, written a3er completion of that ~tudy, describ~s t1l.e ~mrl&apos;: and sunlharizea the fiats obtained. Ifhen tlle stu* oi roof novement bras be,- at Cxcible tw igeas \%.ere a6-r;incsd. on decay of tiriber Q: scne of :he olficialr;: (I.) 9:la.t timber decay v:as unustmlly rapid in ,tho Ciuoiblc mins, ,m?. ((2) that timber coated with rock ri..~st deixiyad morrl mpirlly thnn those %hat vsrc not so coated. Thsx ::ore no records by which tkeso &apos;iaeas could &apos;L;e tertcc?, ard it cnpsarefi vise to make a limite6 in- vo3tiption, p~.rticu!.ai.ly of +.he effect of roc!< dusting on decny, as rock ductirg is nn importnnt mer-ns of ~rc-,rcnt?;~g cad-dust eql-osions. ]

Jan 1, 1941

By Pedro Lilienfeld

This report describes the development, design, fabrication and testing of a port-able, battery-operated, light scattering monitor (henceforth to be designated as ILSDM) for the rapid measurement of the concentration of respirable dust in mining environments. This instrument incorporates state-of-the-art design characteristics and makes use of advanced solid-state components both for light emission as well as for its detection. The use of a pulsed light source combined with synchronous signal detection minimizes drift problems and optimizes the sensitivity of the measurement. Simplicity of operation, reliability and ruggedness, light weight as well as improved performance were salient objectives of this instrument development program. Continuous clean-air flow screening of all critical optical surfaces, and optimized optical detection and electronic signal processing design resulted in about a hundred-fold decrease of noise and drift with respect to precursor instruments. Equivalent mass concentration measurements 88 low as 10 micrograms per cubic meter can be routinely performed with time constants of about 2 second.

Jan 1, 1979

By J. J. Bouillon

"Located in the northwestern portion of the Abitibi greenstone belt, Les Mines Selbaie is a copper-zinc (silver and gold) producer. Felsic tuffs host three are zones. Composed of sulphide veins and breccias, they are not exhalative massive sulphide deposits, except, probably, for the massive pyrite (fragments and lenses) localized close to the top of the volcanic sequence.The total of all (mineable and mined) ore in the three zones presently outlined on the property, is of the order of 29.9 x 106 tonnes with average grade of 0.63 g/t Au, 37.02 g/t Ag, 1.21% Cu, 1.91% Zn.The ore reserve calculations and the daily production procedures are computerized to various degrees. The data handling process is highly computerized.Various geophysical methods are, and have in the past, been successfully used on the property. The ""mise-à-la-masse"" surveys were used to perform the geological interpretation of an underground deposit (A-2 zone). Presently the PULSE-EM surveys are performed in all surface and underground exploration drill holes."

Jan 1, 1990

By L. C. IlsLey

"This paper is intended for State mining inspectors, safety engineers of mining companies, and others interested in electrical safety inspection in mines, It presents the important points that should be watched by inspectors, and briefly reviews the work of the Bureau of Mines in the testing of electrical apparatus or equipment to determine their permissibility for use in gaseous coal mines.Important Points in Inspecting Mine Electrical Installations or Equipment.The following questions are intended as suggestions to a safety inspector who may not have been specially trained in looking for defects in installations or in the maintenance of electrical equipment:1.,Is there someone in charge of electrical equipment who is fitted for this position by ability, training and experience?2.,Is a systematic recorded inspection of electrical equipment made at least once each month?3.,Is a plan map of the mine kept showing all permanently installed electrical machinery and apparatus, including cables, conductors light etc.?4.,Are there instructions for resuscitation from electric shock posted in each surface and underground electrical station, also at the entrance of the mine and in the first aid station and are employees working on electrical equipment trained to apply these instructions in case of accident?"

Nov 1, 1923

By Keith A. Heasley

Numerous different instruments and techniques have been developed for the purpose of measuring rock stress and stress changes around excavations. The interpretation of the output from many of these instruments has often been problematic. This paper covers the research performed in attempting to analyze one particular stress measuring instrument called the Borehole Platened Flatjack (BPF) . The approach used in this analysis was to combine the analytical solution for the displacements around a borehole and the analytical solution for the bore- hole-platen interaction with the empirical stiffness behavior of the flatjack. The resulting model of the BPF response was then verified using measured laboratory data with very good results. In addition, techniques for applying the method to the field are briefly discussed. The major accomplishments of this comprehensive modeling and testing program are; 1) the establishment of the critical installation and site parameters of the hydraulic pressure cell and 2) the development of a systematic procedure for calibrating the cell based on the given values of these critical parameters.

Jan 1, 1989

By H. G. Stephenson, D. Castendyk

Open pit anthracite mining at the Canmore Creek Mines, Canmore, Alberta, south of Banff National Park, resulted in several pit lakes by the early 1970’s. To enable future mining opportunities in the Rocky Mountains, operators decided to reclaim the site into a non-polluting landscape which would provide a memorable outdoor experience for residents and visitors alike, and would preserve wildlife habitat. Reclamation began with the stabilization and revegetation of spoil piles adjacent to Canmore Creek, and the backfilling and revegetation of Canmore Creek Mines No. 1 and 2 to create “Salamander Pond.” The company dammed the outlet of an open pit at Canmore Creek Mine No. 3 to raise the water level and create Quarry Lake. Reclamation concluded in 1980 when the Town of Canmore took ownership. Quarry Lake is now the centerpiece of 293-acre Quarry Lake Heritage Park, a popular destination for swimming, hiking, and fishing, visited by about 400 people on summer days. The Alberta Environment Conservation Authority described this as “The best mine reclamation in Western Canada.” Quarry Lake is an exceptional example of walk-away, pit lake closure, where the mining company created a valued post-mining asset and was released from future liabilities. INTRODUCTION One of the most important environmental issues associated with contemporary open pit mining is the closure of mine pit lakes, and the perpetual legacy these lakes can potentially generate. Ideally, successful pit lake closure includes the following: (i) the water quality within the pit lake, plus surface water and groundwater discharging from the pit lake, meets pre-mining, or other acceptable water quality conditions of the receiving environment, (ii) the termination of all active treatment processes, (iii) the return of the pit lake to the government for long-term care and maintenance, (iv) the release of the mining company from all future liabilities associated with the pit lake, (v) the return the environmental bond to the mining company, and (vi) the reuse of the pit lake for some post-closure, beneficial purpose. The achievement of these goals is known as “walk away, pit lake closure.” Peer-reviewed, publications of successful walk away, pit lake closure provide mining companies the ability to address public concerns regarding the safety of pit lakes which commonly occur during the permitting, operations, and closure phases of mining. To date, most published work on walk away, pit lake closure work has occurred in the coal mining sector in Germany and Australia (McCullough et al., 2009; Jones and McCullough, 2011; Kumar et al., 2013; Schultz et al., 2013). However, in North America, examples of walk away, pit lake closure are not widely discussed in the literature despite there being excellent examples from the coal mining sector in Alberta, Canada (e.g. Pleasure Island, Black Diamond, East Pit, Sphynx, Robb, Lovette, Siltstone, and Sterling), and from the iron mining sector in Minnesota in the United States (e.g. Portsmouth Lake, see MNDNR, 2018). Although seldom included in discussions of pit lakes from the metal and coal mining sectors, the aggregate and fabricated-stone mining sectors also produce pit lakes, and there are numerous examples throughout North America where these pit lakes have been successfully closed and transformed into post-mining resources. The difficulty of finding these good examples in the literature makes it challenging for companies to respond to public and regulatory questions regarding pit lake closure and reuse. As such, there is a pressing need document the motivations and approaches used in examples of successful, walk away, pit lake closure in North America so that the mining industry at large can learn from these examples and can better address public concerns.

Jan 1, 2019

This paper describes the economic study of longwall versus bord and pillar mining using all continuous miners for a colliery located at the South Coast district of New South Wales, Australia. In this district longwall mining appears to be a better economic proposition than bord and pillar. The internal rate of return on investment is found to remain approximately constant for each method irrespective of life. The economic importance of percentage extraction of coal is shown to be small for high values of minimum rates of return, becoming more significant as the minimum rate of return decreases.

Jan 1, 1980

By M. P. Hardy

Copper-Nickel ores in northeastern Minnesota could establish a new industry in a region where underground mining has not been active. This study reviews geotechnical data relevant to the selection and design of underground mines in this region and by numerical structural analysis evaluates the importance of some geotechnical parameters to mine method selection. Because of the rapid development of computer modeling many new techniques have become available for modeling rock mass behavior in recent years. An overview of these methods is presented and their applicability to mine design reviewed. Methods included in this summary were the differential continuum models, such as finite Pint and finite difference, integral continuum models, such as boundary element, displacement discontinuity and boundary integral equation methods, and discontinuum methods such as the distinct block model. The displacement discontinuity method was used to evaluate the influence of geotechnical parameters on some aspects of mine design. Three problems; room stability, pillar stability on a weak inclined contact and sill pillar thickness influence on sill pillar stability, were analyzed to evaluate the relative importance of insitu stress field and joint properties on design. It was concluded that for stability analysis the initial horizontal stress is of most importance in all aspects of design. The position, orientation, persistence and strength of joints is also of primary concern. In a more general sense, however, it was concluded that detailed geotechnical parameters have much less influence on mine method selection than more general factors such as rock quality, initial stress state, orebody shape and economics.

Jan 1, 1978

By Lawrence P. Goldfarb

This paper presents the results of the geotechnical investigation for the repair of the Fashion Island Boulevard Bridge, Bridge No. 350160, in San Mateo, California. The concrete, precast girder bridge suffered considerable damage during the Loma Prieta earthquake. The existing 36-inch, precast, prestressed concrete piles cracked and spalled at their tops. Based on analyses performed by Biggs Cardosa Associates, structural engineers, the piles did not have sufficient strength and ductility to resist the dead plus seismic loads specified in the Caltrans "Bridge Design Specifications". Additional support for the bridge was needed and the repair strategy consisted of installing large diameter pipe piles at the existing bent and abutment locations. This paper describes the geotechnical engineering analysis and design decisions for the large diameter pile design.

Jan 1, 1993

Jan 1, 1963

By E. A. Metz

Perfect combustion in an engine would produce only water vapor, carbon dioxide and nitrogen as by-products; however, complete combustion is never achieved. As a mobile power plant, the diesel engine is relatively inefficient in terms of energy produced from the energy potential of the fuel. The diesel is not a perfect engine. The fuel burned can undergo a very large number of reactions in the combustion chamber. It only stands to reason that a large number of compounds are contained in the exhaust, actually, thousands of chemicals. The exhaust can be broadly divided into a gaseous phase and a particulate phase. Each phase is made up of organic and inorganic compounds. The vapor phase contains carbon monoxide, sulfur dioxide, various oxides of nitrogen and many hydrocarbons. The particulate phase contains clusters of respirable inorganic particles made mostly of carbon. This paper will address the health hazards, as we know them today, of the major components of the particulate phase in the exhaust of diesel engines. It will briefly examine the operational factors of the diesel engine as it applies to particulate emissions. Longitudinal studies of occupationally exposed miners are needed with documentation of levels of exposure before a chronic effect of exposure can be determined. At this time, it is not possible to conclude from human studies the level of diesel exhaust exposure that results in the observed lung cancer risk.

Jan 1, 2001

This paper discusses how elemental analysis of conveyed bulk flows in real time using PGNAA (Prompt Gamma Neutron Activation Analysis) technology has resulted in significant improvements in advancing plant control in mineral processing operations. Basis of operation of the PGNAA through belt, full stream, continuous, multi-elemental, real time analysis technology is explained. Capabilities and limitations in plant operating environments are discussed including comparison with other real time, online technologies through review of published information available for on-conveyor minerals applications. Case studies demonstrate benefits provided by this technology in two operating mines. An iron ore company had prior experience with the PGNAA analyser technology, implementing an early model in a minerals application in 2003 to develop confidence in its measurement performance and usefulness of the data. A number of analysers were subsequently included throughout the new plant design for extensive measurement and control of conveyed bulk flows, from conveying after mining through to rail load-out. A copper-gold company installed an analyser to address copper ore blending issues where an on-belt system was the only viable option for the degree of control required. Analyser suitability was evaluated through test work on site samples to determine customised multi-element precision guarantees for each application. Analyser results from normal operation are compared against laboratory analyses of multiple cross stream samples collected from conveyed flows to assess performance. Both projects discussed were able to realise benefits previously unattainable for plant quality control, surpassing capabilities of traditional technologies which were either unsuitable for measuring conveyed flows with adequate accuracy or in real time. Equipment payback within a few months was achieved for both sites. Through proven performance in these applications, the companies consider the technology an essential component in advanced plant control necessary in new process flow sheet designs, rather than an optimisation tool.

Jan 1, 2014

By H Zhou, T Honeyands, M Zhou

In iron ore sintering, packing the granules onto the sintering strand to form a porous bed with optimum permeability is a complex dynamic process. The packed bed voidage is the key factor determining the flame front speed and the final sinter productivity and quality. Previous studies have found that granules are soft quasi-particles with a typical structure of nuclei with an adhering fines layer. The deformation of the adhering layer greatly affects the bed voidage during packing, which is related to the strength of the adhering layer and the force exerted on the granules. In this study, tablets simulating the particle size distribution in the adhering layer of granules were made for four single ore blends. Both the tensile strength and shear strength properties of these tablets were investigated as a function of water content by the uniaxial compression test and direct shear test respectively. The results of compression tests show that the adhering layer becomes weaker and more compliant with the increase of moisture. The most porous ore has a more rigid adhering layer than the other three tested iron ores at any given moisture content. In direct shear tests, the internal friction angle of the adhering layer ranged from 31&#176; to 37&#176; and varied little with the moisture content or ore type. The cohesion constant is around 1 kPa and is quite small compared to the stress applied to the granules during packing. Combined with the results of granulation and packing experiments, the influence of the adhering fines layer deformation on the degree of voidage loss is specifically discussed.CITATION:Zhou, M, Zhou, H and Honeyands, T, 2017. Tensile strength and shear strength properties of the adhering layer of granules in iron ore sintering, in Proceedings Iron Ore 2017, pp 117–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Draft tube circulators are now widely used instead of Pachucas for suspension of slurries in large tall tanks.Precipitators in the alumina industry are an example.Draft tube/tank diameter ratio is critical. Two independent criteria are given for optimum ratio. The hydraulic and energy relationships are defined. These require an impeller of very high specific speed. For a stable and efficient system the impeller should have aerofoil blades with a pitch angle which decreases from hub to tip.The draft tube must be matched to the impeller with inlet baffles above the impeller and flow control vanes below it. Tip recirculation must be suppressed. The tank itself should have a filleted flat bottom.Such a system exhibits the behaviour of axial flow devices with the characteristic undesirable behaviour at low flow.Installed and operating power requirements depend critically on hydraulic design and to a lesser extent on speed reducer efficiency.The problems of re-suspension have been overcome by a patented slot system which also improves behaviour at low flow to permit a more economic design. A number of other practical operating considerations are also discussed.

Jan 1, 1982

By Chad W. Brown

"A study of five commercially available solvent-extraction diluents in combination with three commercially available extractants under sub-Saharan African copper solvent-extraction conditions yielded intriguing results. A variety of physical and chemical property analyses showed that the diluents have some property differences, but overall the properties are similar and provide comparable solvent-extraction performance. Although each physical chemical property technique provides useful information, no individual test result suffices for prediction of diluent performance. Furthermore, a diluent should be evaluated within the conditions for which it is targeted to determine a true measure of performance. Overall, the diluents studied possess appropriate physicochemical properties for sub-Sahara Africa copper solvent-extraction conditions and can be utilized to achieve efficient, safe and reliable operations. INTRODUCTION Background Today, commercial SX diluents are available globally from a limited number of manufacturers. Production quality and consistency of these diluents have improved tremendously over the past 20 years. For example, diluent flash points have been increased incrementally to improve transport and handling while reducing fire hazards. In addition, properties have been successfully modified to minimize evaporative losses, ultimately reducing SX plant raw material costs. Diluent manufacturers have also focused on meeting performance requirements of SX plants, including eliminating components detrimental to SX operations, such as olefinic groups that can react with various species resulting in changing phase-disengagement properties over time, as well as ensuring that proper hydrocarbon components are present within diluent mixtures to maintain good reagent–metal complex solubility. These challenges have been met in the midst of ever-increasing stringent environmental regulations. Sub-Saharan Africa copper SX operations pose a unique set of conditions for diluents due to inherent ore compositions and the associated high reagent concentrations required for complete copper extraction. Chevron Phillips Chemical Company, LP has been manufacturing hydrocarbons and hydrocarbon-based diluents since the mid-80s, applying this experience to identify the physical properties considered crucial for proper performance in SX operations. This paper documents the findings of a study utilizing commercially available diluents in combination with extraction reagents commonly utilized in African SX operations to evaluate the relative performance of the diluents under sub-Saharan Africa copper SX conditions."

Jan 1, 2015

By John Brulia

You’ve probably heard the old expression, “The more things change, the more they stay the same.” But the adage doesn’t seem to hold much water when it comes to making a telephone call on the road. Thirty years ago, a “powder hound” had to stop his 2-wheel drive vehicle at either a roadside diner or a telephone booth to make a call using a public telephone. But, fast-forward to 2007, and a contemporary “explosives engineer” driving his or her 4-wheel drive vehicle simply makes a call “on-the-fly.” The fundamental difference between these two eras is the result of the introduction and the proliferation of cellular or wireless technology. On the one hand, this fundamental difference is much welcomed in the form of personal and business conveniences; and improved productivity. On the other hand, this fundamental difference creates a new set of un-welcomed conditions causing a potential “digital danger.”

Jan 1, 2008

By G. L. Smith

This paper introduces and defines the concept of a linkage between long-term planning parameters (?global assumptions?) and possible future world views as conceived in scenario planning. Scenario planning, the tool that is used to arrive at plausible future worldviews, is described in the context of the platinum industry. The interpretation of the scenarios into long-term planning parameters is made, followed by an illustration of how the long-term planning process has been adapted at Anglo Platinum to include the notion of uncertainty.

Jan 1, 2008

By David K. Hylbert

This study was designed to investigate roof falls in room-and-pillar drift coal mines and to determine geologic methods for predicting unstable roof conditions. The study area was located in Harlan County, Kentucky and the Bailey Creek (Harlan coal bed) and Highsplint (Darby coal bed) mines were selected for study. Correlations were made laterally between surface outcrops and within the mines using lithologic and trend analysis criteria. Lithologic criteria compared cyclic changes in roof strata. Results indicated that roof falls are associated with zones of weakness within or between five vertical cycles recognized. Abrupt lateral facies changes occur. In the Highsplint mine the roof was classified in four categories or conditions using 98 rib sections for control. Structure contour and isopach maps were used to project axial trends of the sandstone roof. A roof-fall zone was examined using ten NX cores taken from the roof and included lithologic, petrographic and clay mineral studies. At the Bailey Creek mine roof failure was caused by the heading direction being driven subparallel to paleochannel directions. Computer programs were used in trend analysis studies. Cross-bedding, paleo-channel trough axis and sole mark studies indicated a 350 discrepancy between surface and in-mine trough axes at Highsplint. A direct relationship between joint and "slip" frequency and direction with sandstone roll trends was found. Surface joints compared well with drainage Segments, hilt did not correlate with roof falls in areas of mines under overburden in excess of 600 feet.

Jan 1, 1977

By Secretary of the Interior

"INTRODUCTION The Bureau of Mines Synthetic Liquid Fuels Program again forged ahead during 1952, and important technical advances led the way to improved methods of converting coal and oil shale into liquid fuels. Marking the eighth year of activities under this program, the pact 32 months brought a new domestic industry nearer realization.The increasing demand for gasoline and oil and the rising cost of finding new petroleum, coupled with America's growing dependence on imports and the unsettled international situation, have continued to emphasize the importance of the Bureau's Synthetic Liquid Fuels Program. Oil, the indispensable material of wartime, likewise has critical importance in peacetime, touching as it does the life of every individual. Supplementing petroleum with synthetic liquid fuels will not only conserve this Nation's petroleum reserves but also will bring into greater use its tremendous reserves of coal, as well as the vast deposits of oil shale for which no other practical use has yet been found.The Bureau of Mines Synthetic Liquid Fuels Program is one of the most important and far-reaching of the Government's research projects. Through development of commercial synthetic liquid fuels, the United States can obtain oil products from its great inland reserves of coal and oil shale to supplement petroleum in any quantity that may be necessary, consistent with economic and other requirements, such as national defense. The use of raw materials from such deposits would be of highest importance in wartime, when shipping lanes are menaced by the enemy. The Synthetic Liquid Fuels Program of the Bureau of Mines and research efforts of industry have advanced. American technology to the point where it is now possible to begin the design and construction of prototype plants. Certainly, significant improvements will be made as the program continues, but this prospect in no way alters the fact that the start of prototype plants should be encouraged. These plants, as the first step in the development of a synthetic fuels industry, would serve a threefold purpose:"

Jan 1, 1953

By Gift Chisakuta, Bravo Mbao, Nils Schwarz, Angus Feather, Anthony Mukutuma

Bwana Mkubwa is a 50 000 tons per annum copper cathode producer, owned by First Quantum Minerals and located in Ndola, on the Zambian Copperbelt. The Bwana Mkubwa solvent-extraction circuit was started up in 1997. In 2002, the plant began treating ore from First Quantum?s Lonshi mine located in the Democratic Republic of Congo. The Lonshi ore is exceptionally fine and the amount of solids in the feed solution reporting to the solvent-extraction feed solution increased dramatically. Initially, crud was filtered in a filter press, but this rapidly blinded and seldom produced anything better than a wet sludge containing large quantities of organic. In December 2003 the decision was made to install a Flottweg Z4E-3/441 Tricanter® centrifuge to recover organic from the crud. The installation was completed in June 2004 and has since led to significant improvements in plant operability and savings in organic consumption.

Jan 1, 2007