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By Joan K. Kuenzi

This Information Circular brings together for consideration recommendations from U.S. Bureau of Mines research in the area of surface mine mobile equipment maintenance for the period 1982 through 1991. It updates the 1982 contract report by Baker and Alves that formed the basis for much of the work described in the present report. Recommendations for hazard abatement during work on mobile one equipment are presented and stem from the results and recommendations of the research in two areas: (1) equipment and workplace hazard reduction, and (2) management of maintenance information. Recommendations included in this report apply to both the operators and maintainers of mobile mining equipment as well as to the manufacturers of that equipment.

Jan 1, 1995

By Floyd G. Anderson

This report reviews and summarizes information on prevention and suppression of dust in mining, tunneling, and quarrying published in the United States during the years 1958 through 1960. Unpublished pertinent data developed or assembled by the Bureau of Mines during this period also are included. Silicosis statistics reported by the U.S. Public Health Service indicate a sizable silicotic population in the United States and suggest a need for greater dust-control effort. A joint medical-environmental survey was begun by the U.S. Public Health Service and the Bureau of Mines to evaluate the magnitude of the silicosis problem in the metal mining industry in the United States.

Jan 1, 1962

By Roy C. Bartholomae

This U.S. Bureau of Mines study found that the performance of the active noise cancellation hearing protector in a reverberant field was mixed. The performance varied when the conditions changed from ideal to nonideal. The active noise cancellation (ANC) component provided substantial additional noise reduction from 125 to 500 Hz for all testing conditions (broadband noise or pure tones both with and without safety glasses). While the ANC under ideal conditions provided additional attenuation from 500 Hz and below, under nonideal pink noise conditions the ANC amplified noise below the 125-Hz third octave band. There was a middle band of frequencies at which the ANC amplified noise levels ranging from 630 to 4,000 Hz. The results for pure tones showed that attenuations were higher but that they followed the same general trend.

Jan 1, 2010

By T. J. Batchler, K. M. Mohamed, D. F. Gearhart, R. K. Zipf

Seals are explosion-resistant structures built in underground coal mines to isolate abandoned mining areas from the active workings. An equivalent single degree of freedom (SDOF) method such as the single-degree-of-freedom blast effects design spreadsheet (SBEDS) developed by the U.S. Army Corps of Engineers can be used to design seals to resist mine explosions. The critical input for the SDOF code is the seal resistance function. The objective for this study is to develop engineering data for design of plain concrete (PC) and reinforced concrete (RC) seals using finite element (FE) models. The FE models can then be used to generate resistance functions for different PC and RC seal designs, which can be used in the SDOF codes. The U.S. National Institute for Occupational Safety and Health (NIOSH) researchers designed and built a test fixture for use in conjunction with NIOSH’s Mine Roof Simulator to apply a four-point bending load on the face of the tested seal. Eight large-scale experiments for each PC and RC seal were conducted. The experimental design considered the effects of the foundation strength, hitching and roof-to-floor convergence. Calibrated FE models for PC and RC seals were developed using ANSYS Ver. 13. With a very limited number of engineering-based assumptions and a single set of data—including Young’s modulus, compressive strength, stress-strain relationships, etc.—the PC and RC seal models successfully calculated the recorded resistance functions and failure patterns for a wide range of boundary conditions. Plug and RC seals were assumed for a 1.83-m- (6-ft-) high entry to demonstrate the application of the calibrated finite element models for calculating the resistance functions of these seals. The resistance function of a particular plug seal case was found to be a bilinear relationship. The resistance function of a particular RC seal without shear reinforcement was found to be a nonlinear relationship.

Jan 1, 2013

By Roy A. Anderson, Roger H. McConnel

The Metaline district from 1906 through 1965 has produced nearly 16 million tons of ore yielding 400,808 tons of zinc and 178,062 tons of lead. The sediments, ranging from Precambrian into the Devonian, are schist, phyllite, conglomerate, greenstone, quartzite, limestone, dolomite, and carbonaceous slates. Quartz monzonite and granodiorite of the Cretaceous(?) Kaniksu batholith are exposed over a large area beginning a few miles south of the district. There is minor Tertiary conglomerate and basalt. Abundant glacial deposits obscure much of the bedrock. Northeasterly trending folds, having steep to overturned northwesterly limbs, and thrust faults, striking northeasterly and dipping southeasterly, characterize the deformation of the Precambrian and Paleozoic rocks. Recent drilling indicates that the Slate Creek fault, too, is also a southeasterly dipping thrust fault. This new evidence suggests that the Valley Block, like the other major structural blocks, may in part be a thrust plate rather than a graben, and that thus the district may have greater structural unity with the surrounding region than has heretofore been apparent. The Cambrian Metaline Formation of limestone and dolomite contains essentially all the lead-zinc mineralization. Most of the ore mined to date has come from a carbonaceous and irregularly siliceous breccia of sedimentary and diagenetic origin, locally called the "Josephine Horizon," that makes up the top few to 200 feet of the formation. The Josephine Unit is a breccia of gray limestone, coarse light gray dolomite, very thin-bedded, dark gray siliceous dolomite, and "zebra rock" believed to be of algal origin, embedded in a matrix of black dolomite or black jasperoid or some mixture of these two. The jaspcroid fragments and irregular blobs embedded in the black dolomite matrix and the jasperoid laminae in the very thin-bedded dark gray dolomite suggest that jasperoid was formed at the same time as the breccia matrix and as the laminated dolomite. So too, the marked tendency of sphalerite and galena to be disseminated mainly in the dark breccia matrix and their tendency to be most abundant in the jasperoid laminae of the very thin-bedded dark gray dolomite, even where the mineralized and laminated dolomite is fragmented and engulfed in black dolomite breccia matrix, suggests that in these ha bits the sulfides also were deposited contemporaneously with the sediments. Yet very commonly, veins and vague veinlets and patches of white quartz, usually carrying rather coarse sphalerite and sometimes galena crosscut all rock types. These contradictory relationships throughout the Josephine Unit suggest that both the black jasperoid and the sulfides were original constituents of the Josephine Unit but that, locally, they later were remobilized and deposited as white quartz and coarser grained sulfides. Possibly, at least in part, this "metamorphism" is one of the effects produced during or shortly after the intrusion of the Kaniksu batholith.

Jan 1, 1968

By Karl Berger

The paper gives a comprehensive overview of the historical development of various metal rolling technologies and also describes the influence to industrial and socio-economic developments. The rolling of steel, in particular of rails, beams, rebar, strip and plate has enabled the large scale transport and travel, the building of bridges and buildings, the manufacturing of ships and cars. All this has changed the face of the world significantly. Further the paper approaches technological highlights in the design, manufacturing, drive and control of modern mills and the various types developed to create industrial economic units for the different markets and customers’ requirements. An outlook of future challenges is as well discussed in the paper. Various solution approaches for the rolling technologies, from continuous improvement of existing plants to more radical new concepts like endless rolling, near net-shape casting and rolling are approached. A positive conclusion is drawn that rolling technologies will remain a valuable area for engineers with scientific and economic challenges, but also a clear vision for positive contribution to further industrial and social development.

Jul 30, 2018

By Niels Verbaan, Ernesto Bourricaudy, Ronald Molnar, James Brown, Sunil Jayasekera

"SGS Minerals commissioned an internal R&D program to develop in-house expertise to design, set up and operate REE separation pilot campaigns at its Lakefield, Canada site. A team approach was used that included expert consultants in the field of REE separation as well as in-house expertise supported by the on-site Analytical Laboratories.A mini pilot scale SX circuit was designed and constructed consisting of several modular banks of 30 stages each. About 80 stages of mixer-settlers were used to separate Pr and Nd from La and Ce contained in a synthetic REE chloride stream simulating the raffinate from an initial La-Nd|Sm-Lu+Y separation.Two pilot campaigns were operated totalling 25 days of 24/7 operation with 99.4% plant availability in the final 20 day campaign. Purities of > 99.9% in the Pr-Nd strip liquor and > 99% in the La- Ce raffinate were achieved and simultaneously sustained in the second campaign for prolonged operating periods. Key to controlling and adjusting the circuit was the rapid assay turnaround (as low as 2 hours) provided by the on-site SGS analytical lab. This permitted the operating team to modify conditions and observe the effect of changes relatively quickly considering the large number of stages. A portable XRF analyser was also used to track evolving assay trends in the circuit. The small physical size of the circuit enabled longer operation with a limited amount of sample.This paper discusses the design of the circuit, operating conditions, some of the key operating factors and controls and results obtained.INTRODUCTIONSGS Minerals commissioned the design of and built a solvent extraction (SX) pilot plant for the separation of rare earth elements (REE). The plant consists of a battery of 120 mixer-settlers set up in a dedicated piloting facility.The purpose of the programme was to develop capabilities and in-house expertise in REE SX separation technology. The program aimed to establish operating procedures, sampling regimes, and analytical methodologies and protocols for this type of process/plant. A team comprised of SGS personnel and several external consultants with prior industrial and REE separation piloting experience was assembled to achieve these objectives."

Jan 1, 2016

By Lloyd A. Morley

This seven-chapter document is the first volume of a two-volume report that presents a comprehensive outline of coal-mine electrical power systems from theory to practice. Together, the two volumes contain the vital aspects that go into planning and designing a mine power system. After a short introductory chapter, Chapter 2 discusses the history of electrical use in mining and introduces "typical" mine- power-system arrangements. Chapter 3, 4, and 5 supply basic information on electrical theory, circuit analysis, and motors. Next, the Grounding and Distribution Chapters detail unique aspects of mine power systems. Elements of surface and underground use are included in all these chapters. An index concludes Volume I and is cross-referenced to both report volumes.

Jan 1, 1982

By Paul Thurlow, Richard K. Lipscombe

The measurement of deflection of designed diaphragm walls is critical for near real time information to assess wall and soil behaviour as the internal area is excavated in a controlled manner. Data enables the site team and designers to check performance of the design, which is linked to safeguarding the site and the external stakeholders.This paper documents the use of Shape Accel Arrays at the Tottenham Court Road Western Ticket Hall during excavation and propping within the diaphragm wall for the Crossrail project. It shows how the data obtained was used within the site settlement management plan to assist in the control of the works and the information used for Value Engineering purposes that benefitted the project.The use of Shape Accel Arrays for measuring the deflection of retaining walls is not commonplace in the UK construction industry, with the Tottenham Court Road Western Ticket Hall being one of the first times they have been used in such a way. A detailed analysis of the data obtained from the instruments has been undertaken, and compared to the results obtained from the manual inclinometers that were read next to the SAAs. The advantages of the relatively new SAAs have been discussed, as well as other applications of the instrument.

Jan 1, 2017

By N. B. Greninger

The U.S. Bureau of Mines conducted explosion tests on various full-scale cementitious bulkheads used in abandoned mine areas to evaluate the ability of the bulkheads to withstand gas explosion over-pressures of 20 psig. Tests were performed on 120-ft2 solid-concrete-block seals of varying thicknesses and designs. Of the seven solid-concrete-block seals tested, only the standard-type seal, having a 16-in thickness, keyed at the floor and ribs, all joints mortared, wedged at the roof, and a center pilaster, maintained its integrity when subjected to a 20-psig pressure wave. After being subjected to repeated explosions, the standard seal only showed a small hairline crack and had an air leakage of 87 ft3/min at a pressure differential of 1 in H2O. Tests were performed on cementitious foam seals of varying thicknesses and compressive strengths. Explosion tests have shown that 200-psi strength, 4-and 8-ft-thick seals can withstand a 20-psig pressure wave. At a pressure differential of 1 in H20, no air leakage was detected through the 200-psi, 8-ft-thick foam seal.

Jan 1, 2010

By K. Esmaieli

The Synthetic Rock Mass (SRM) approach has the potential to capture the mechanical behavior of large rock samples. In order for the method to be used with confidence it is necessary to gain a good understanding of the factors that influences its analysis. This paper reports on a series of numerical experiments, based on field data from a large underground mine, to investigate the influence of intact rock mass strength of a constructed (SRM). A jointed rock mass defined by three fracture sets was simulated by a Discrete Fracture Network (DFN) model. The generated fracture network was subsequently embedded into six different intact rock samples, simulated by a bonded particle model in PFC3D, generating six SRM samples. Each intact rock sample was 7 m × 7 m × 14 m and assigned different mechanical properties. The first intact rock sample was assigned a uniaxial compressive strength of 205 MPa and an elastic modulus of 104 GPa with the UCS and elastic modulus values of the other samples downgraded by 10% until the weakest sample had a UCS value of 121 MPa and an elastic modulus value of 61 GPa. All SRM samples were loaded under uniaxial compression to obtain the complete stress strain curve. It was observed that the compressive strength of the rock mass samples decreased by 10% following the same trend as the rock material strength. However, the elastic modulus of the rock mass samples decreased non-linearly with reduction of the elastic modulus of the rock material. The Poisson's ratio of rock mass samples does not change with decrease of rock material properties. For the post-peak behaviour the results show that both the brittleness index and the residual strength of rock mass samples decreased as the rock material properties degrades.

Aug 1, 2013

By J. H. C. Scrimgeour, T. Toong, R. E. Hamilton

"The principles involved in the use and application of mathematical models as an aid to the development of advanced process control computer systems are described briefly. This is followed by a brief survey of known models of this kind for the simulation of mining industry processes.The main part of the paper describes a dynamic model of the flotation process developed by Canadian General Electric. Using flotation rate constants for each species of mineral and gangue, the model provides a numerical solution of the differential equations describing cell behaviour. The cell mode] is used repeatedly as a subroutine in the •over-all-plant model. The features of the cell and plant models are described.Simulation runs from the plant model show stream .assays and other indications of plant behaviour printed typically in 1-to 10-minute steps for several hours of •Operation following typical disturbances such as changes in feed rate or reagent addition rate. The simulation can :Show expected behaviour for both uncontrolled and computer-controlled plants."

Jan 1, 1970

By L. E. Djingheuzian

IN 1953, Lewis (1) published an article which brought forth a great amount of discussion by grinding engineers. In his contribution to discussion the present writer (2) suggested that, for the most efficient performance of a ball mill, there must be a .definite relationship between Cn, per cent critical speed, and V p, per cent mill volume occupied by the ball charge. Later, he ( 3) was able to publish some grinding data from Wright-Hargreaves milly which appeared to bear out this contention. It is with this view to establishing a fundamental relationship between Cn and Vp that the idea of this Forum was conceived. Accordingly, a questionnaire was prepared and copies of it were mailed to over eighty Canadian mill operators. This questionnaire did not include a question on dilution on the assumption that each mill operator was using the most efficient dilution for his operation, nor was a question on efficiency of classification included since it was thought that the inclusion of efficiency of dassification in the questionnaire at this preliminary stage might render the forum discussion,. while everybody was trying to find his bearings, too unwieldy. However, it is evident that, as discussions develop, this forum will have to define a uniform method for establishing most efficient classification in grinding circuits

Jan 1, 1957

By Christoph Aichinger

A smart combination – Primetals Technologies developed the Circular Pelletizing Technology (CPT), which is a combination of the well-proven travelling-grate pelletizing technology with the design of a circular dip rail cooler of modern sinter plants. The overall space requirement and the installed weight for a CPT plant is significantly less compared to conventional technologies and by that CPT is a very attractive alternative for new projects.

Aug 16, 2017

By Guy Archambault, Réal Daigneault

"Un trait marquant du cadre tectorwstratigraphique de la Sous-province de l'Abitibi est la présence de nombreux couloirs de déformation d’extension régionale et sub-concordants au grain stratigraphique. La présence de grandes masses granitoïdes qui perturbent l'allure du grain tectonique est typique de la partie nord de la Sous-province de l'Abitibi. Des rides E-W constituées de complexes plutoniques précoces forment des reliefs structuraux agissant comme des moles résistants qui interfèrent avec la déformation régionale.Deux types de couloirs de déformation sont distingués, les couloirs de bordure et les discontinuités structurales. Les couloirs de bordure représentent des auréoles de déformation élevée qui s’accompagnent généralement d’un métamorphisme au faciès amphibolite. lls suivent /'interface entre les roches granitoïdes et les assemblages supracrustaux. Ces couloirs sont de puissance kilométrique et sont confines, surtout au sein des roches vertes, a l’interface des complexes granitoïdes d’importance. La limite entre la Sous-province de l'Opatica et les roches supra crustales de l'Abitibi est caractérisée par un important couloir de bordure issu possiblement d'un chargement tectonique irrégulier et concentre lors du raccourcissement horizontal.Les discontinuités structurales sont des failles ductiles qui se propagent surtout en direction E-W mais avec des variantes de directions SE et NE. Les discontinuités E-W se caractérisent par la présence d'une linéation d'étirement à fort angle de chute. Les discontinuités SE sont caractérisées par des linéations d'étirement horizontales et directionnelles et les mouvements observes sont system attiquement dextres. Les discontinuités NE sont des failles à comportement beaucoup plus fragile et se distinguent par des composantes de mouvement senestre. Elles sont tar dives par rapport aux discontinuités E-W et SE et ne représentent pas la symétrique du système SE.La combinaison des systèmes E-W et SE décrit un motif anastomose a l' échelle régionale. Les failles ductiles se rejoignent defaçon asymptotique, isolant des blocs peu ou pas affectes par la déformation. L'anastomose est un phénomène qui se produit a toute échelle et est reliée principalement aux Mt érogénéités et aux anisotropies 1) des forces agissantes (champs de contraintes régionale et locale) et 2) de la réponse del' empilement supra crustal (compositions différentes, fabrique initiate, propriétés mécaniques variées, niveaux d'altération).Dans le but de respecter un raccourcissement horizontal N-S, différents modelés sont proposés; ils mettent en cause soit une transpression dextre, soit des failles inverses réactivées en failles décrochèrent dextres soit des failles de chevauchement redressées."

Jan 1, 1990

By AIME AIME

THE Engineering Education Committee of the Institute convened at the Engineering Societies Building on Feb. 18, .1929, with. E. A. Holbrook, dean of the Schools of Mines and Engineering, University of Pittsburgh, in the chair. STATISTICAL' STUDY OF STUDENTS IN MINING The first paper, a statistical study of the students enrolled in courses leading to a mining degree in 40 institutions, was presented by H. D. Keiser,, assistant editor of the Engineering and Mining Journal; who gave a brief outline of an article he was about to publish in ?that journal?. The complete article appears in the issue for March 30; 1929: To avoid repetition the results are summarized as follows: A request was sent to 42 institutions which give courses in mining' for the number of students enrolled as freshmen; sophomores; juniors, seniors and special students in mining for the years 1925-26, 1926-27, 1927-28, 1928-29. Two of these colleges replied that there were no students in mining. Students' enrolled in courses in metallurgy, geology and engineering, other than mining, were excluded from the statistics:. The statistics received were arranged in, four groups, according to the completeness of the information. One complete group of 25 institutions 'shows as follows:

Jan 1, 1929

By P. G. Kovalchik

Safe electrical operation of shuttle cars depends upon maintaining the trailing cable's conductor temperature below 90° C. However, trailing cables are wound on and off reels, which changes the heat transfer characteristics of the cable-reel system. Derating factors for trailing cables are an attempt to adjust for this changing heat transfer mechanism in a practical way. The U.S. Bureau of Mines conducted research to determine acceptable derating factors for reeled mine trailing cables, using four cable-reel combinations, representative of industry usage. Cables were continuously and intermittently loaded at different duty cycles with direct currents of different magnitudes. Relationships between the average temperature rise and current load were established for each layer of each cable. Two models were constructed; one used empirical data from the continuous and intermittent load tests, and the other was based on thermodynamic theory. Results obtained from the theoretical model were compared with those from the empirical model for the rated temperature rise of the cable. Both models can be used to simulate a variety of test conditions including those that normally cannot be conducted in the laboratory. This information was used to determine acceptable derating factors for each layer of these cable-reel combinations.

Jan 1, 1994

"Accelerated expansion of Western Canada's metallurgical coal industry has again stimulated considerable exploration activity in the Rocky Mountain Foothills Belt and influenced much of the R&D related to transportation, processing and carbonization. Preparation R&D has included further pilot-plant work on desulphurization, spherical agglomeration and modified compound cyclones (which are also proving themselves in other mineral beneficiation studies). Combustion research, aside from increasingly stressing control of combustion source pollution, has directed special attention to lignite PF firing and problems arising from lignite ash. Studies directed toward the non-fuel utilization of coal have centered on such diverse topics as active carbons, carbonaceous filter media, plant nutrients and industrial applications of humic acid derivatives. In addition, a number of long-range research projects related to such matters as coal chemistry and pyrolysis have been actively pursued, and further attention has been given to improved sampling techniques and analytical methods."

Jan 1, 1969

By S. Mohanta, S. Chakraborty, B. C. Meikap

"An air dense medium fluidized bed separator is an efficient dry process for the removal of undesirable gangue material from run-of-mine coal. Its cleaning performance depends on a variety of operating parameters that are interrelated in unknown, complex ways. A literature review showed that these parameters' effects had been experimentally investigated using a traditional one-variable-at-a-time approach, which is highly inefficient and sometimes misleading because many of the parameters often interact with each other to alter the overall equipment performance. Also, it is realized that the interrelationship among these parameters can have a significant effect on equipment performance. Therefore, to correctly evaluate the effects of individual parameters as well as their interactional effects on the separation performance of an air dense medium fluidized bed, we conducted a scientific study based on response surface methodology. Empirical models for two key response variables, namely, product ash and combustible recovery, were developed and subsequently used for identifying an appropriate operating region to achieve optimum separation performance. Furthermore, the optimum performances predicted from the empirical models were validated against experimental data. Preliminary results show a strong interaction among the operating parameters investigated in this test program.IntroductionFluidization is widely applied in industry for its various useful features. In the coal industry, it is used in the air dense medium fluidized bed (ADMFB) separator for the beneficiation of run-of-mine coal. In this separator, a medium is created by suspending fine magnetite particles in an upward air flow, and this pseudo-fluid is used as the beneficiation medium, with the lighter coal particles floating to the medium’s surface while heavier particles sink to the bottom. This separation technique had been receiving a significant amount of attention worldwide in recent times for its specific advantages of low operating cost and less restriction for small capacities (Luo and Chen, 2001; Sahu et al., 2009; Dwari and Hanumantha Rao, 2007; Van Houwelingen and de Jong, 2004), but it is still not a well-established industrial practice because of the availability of efficient wet processing technology. However, with a revival of interest in the dry beneficiation of coal, in general, and ADMFB, in particular, there is once again a concerted effort to improve the efficiency of the ADMFB process, and successive improvements have been made to make this process a competitive and viable option. The existing literature reveals that most of these research efforts had been essentially focused on the identification of a single parameter that has a key influence on separation performance, without taking notice of parameter interactional effect. For example, Luo et al. (2004) proposed a pressure drop number to distinguish separation performance without considering the bed height and gas velocity, which are intimately related to this proposed pressure drop number."

Jan 1, 2015

By V. G. Papangelakis, M. Cheung, M. Dry

The high pressure acid leaching of laterite was modelled and simulated using a combination of two commercially available software packages, namely Aspen Plus 11.1 and the OLI Stream Analyzer. New kinetic parameters for the acid-controlled metal dissolution and precipitation reactions at temperature were first determined from previous experimental data on the leaching of limonite. A grain model with cylindrical pellets was used to model the solid-liquid dissolution reactions. Precipitation reactions were modeled via aqueous equilibrium chemistry. A dedicated thermodynamic database previously developed at the University of Toronto was used in conjunction with the OLI software to model the solution chemistry and calculate the concentration of hydrogen ions in solution at the leaching temperature. Mass balances were handled by Aspen Plus. The simulation gave good predictions of nickel dissolution under industrial and laboratory conditions, for the dissolution of limonite and limonite/saprolite blends. Computational

Jan 1, 2005