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By R Morrison, P Walters, B Adair, V Jokovic

‘Grade Engineering<sub>®</sub> is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams to existing mine plans as part of a system-view’ (Walters, 2017). Two of these technologies are directly recoverable through screening stages: Natural Deportment and Induced Deportment. The potential for taking advantage of “Natural Deportment” by size following blasting and crushing has been demonstrated for a range of ore types. Simple and low cost screening can in some cases generate a fine product with improved grade and a lower grade oversize which can be directed to leach or to waste. Where an ore body consists of many different ore types, the traditional approach of blending to metal grade will often add to complexity of treatment, which will reduce the effect of “natural deportment” by size.CITATION: Jokovic, V, Walters, P, Adair, B and Morrison, R, 2018. Applying enhanced grade engineering to complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 21–23 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

R. H. THURSTON, Cornell University, Ithaca, N. Y. (communication to the Secretary): The " tri-axial diagram" was, I think, first employed by me in the work of the " U. 8. Board Appointed to Test Iron, Steel and Other Metals." A model was exhibited to the American Association for the Advancement of Science, and the diagram was first published, and the model described, in a paper presented to the same society at its Nashville meeting in 1877." The problem then presented to its inventor was to find a method of planning a research involving proportions of ternary compositions in such manner that, a limited number of such compositions being tested, the results should give the law of variation in the physical properties of all possible combinations of the three elements, and the actual numerical values of such as were important to the investigator. The investigation of the binary alloys, copper and tin, copper and zinc, and tin and zinc, had been completed and satisfactorily discussed, employing the usual bi-axial diagram, of which the ordinates represented the one, and the abscissæ the other, of the characteristic properties to be studied, the composition being commonly indicated by the abscissæ. In these cases it was easy to ascertain, by the study of a limited number of compounds, the law of variation in strength, ductility, etc., with composition; but, for a long time, the ternary alloys were not attacked, because no simple and satisfactory method presented itself of securing results significant for the whole field by the investigation of a comparatively small number of alloys. The tri-axial diagram was finally hit upon as a means of representing and interpreting results, and researches were at once begun, and in due time satisfactorily completed.

Jan 1, 1899

By M. P. Ahola

This U.S. Bureau of Mines report presents an overview of the use of three unique numerical modeling methods to analyze cutter roof problems in underground coal mines. Cutter roof failures are common in coal mines where the immediate roof is comprised of thin laminae exposed to highly biaxial tectonic stress fields. The predominant mechanism for failure is assumed to be excessive shear stress at the entry corners exceeding the shear strength of the rock. Early work in this area utilized the finite-element method and then the boundary-element method to analyze several cutter roof control measures. Various stress control measures were simulated to estimate their respective effects on reducing the high levels of shear stress at the entry corners. More recent studies made use of the discrete-element method. This method was used to take the analyses beyond the elastic continuum limits to simulate the propagation of a shear fracture and subsequent redistribution of stress within the mine roof. A simple roof bolt model was implemented to show the benefits of bolting to increase the resistance to shearing and separation along horizontal bedding planes and maintain roof stability.

Jan 1, 1991

By John L. Dahle

This report documents the research efforts that were undertaken to design, install and test noise abatement devices for use on off-highway haul trucks operating in surface mines. The objective of the program was to reduce the environmental noise from haul trucks. The noise reduction devices that were developed utilized existing technology and were tested on a 50-ton haul truck. The efforts emphasized the reduction of noise emitted from the engine compartment which included the use of side shields, sound absorbing material, improved radiator shroud design, and a modulating clutch fan. Noise tests were conducted using modified SAE test procedures for measuring sound levels around a stationary and moving machine, and inside of the operators compartment. Test results showed a maximum of 4 dB(A) reduction measured 16 feet from the truck. Interior cab noise was reduced 6 dB(A) with the windows and vents closed.

Jan 1, 1983

By Gerard C. Gambs

The electric utility industry is the largest customer of the U.S. coal industry, consuming nearly 50% of present coal production. By 1980, the electric utilities are expected to burn over 500 million tpy of coal or 75% of total coal production. When coal is burned in electric utility plants, ash is produced in one of several forms. These include fly ash, bottom ash and bottom slag. At the present time, approximately 20 million tons of these ashes are produced and must be disposed of by the utilities at a cost of 50[c] to $2 per ton. In 15 years, more than double this quantity will be produced. Only a small quantity of this ash is put to any practical use. Much remains to be done about expanding uses for fly ash and bottom slag.

Jan 1, 1967

By C. M. Fellman

THE over-all picture of safety in mining has been encouraging during the past few years, and in mining activities as a whole the trend in accident occurrence is downward. This is the more noteworthy when the type of labor used in mines during the war period is taken into consideration. The drafting of young mining employees into the armed services and the departure of others for work in other war industries took a heavy toll of young, husky, active men. Their places were taken in large part by older men who returned to the mines, or by inexperienced men with little if any knowledge of mining. Despite the lack of labor and especially of skilled labor, and the difficulty of obtaining new equipment as well as maintaining and replacing worn or broken equipment, and numerous other difficulties the mining industry not only reached and maintained maximum production but made the increase with little if any sacrifice of safety. In fact, in many instances better safety records were. established than in normal

Jan 1, 1946

By Rachel Santos Mendes

O objetivo deste trabalho foi analisar o refinamento da liga Al AA1070 deformada via ECAP (Equal Channel Angular Pressing) pela rota A em dois passes consecutivos. O material foi prensado a frio e a deformação verdadeira acumulada foi de 2,38. A caracterização microestrutural foi realizada com o auxílio da técnica de MEV. E a evolução da textura foi analisada através da técnica EBSD. A avaliação do comportamento mecânico da amostra foi realizada através do ensaio de microdureza de Vickers. Os resultados mostraram uma intensa redução no tamanho de grão após o 1º passe, seguido de um decréscimo considerável no 2º passe. A orientação encontrada na textura inicial evoluiu de {1 1 0} para {5 13 1} após o 2º passe. O comportamento mecânico apresentou um estado estacionário entre o 1º e 2º passe devido à ocorrência do fenômeno de recuperação dinâmica. Concluiu-se que um refinamento considerável foi obtido.

Aug 8, 2018

By R. J. Lytle

INTRODUCTION Prior to excavation in soil and rock, it is useful to know the subsurface structure. This is important information both for safety and for equipment scheduling reasons. It is useful to know whether parts of the subsurface might be potentially troublesome or of different character than is generally thought present. By using geophysical probing, it is possible to infer the location and size of these unusual regions. The ground structure is commonly estimated from core samples taken from boreholes. These cores give a detailed knowledge of the structure in the borehole. However, knowledge of the structure exterior to the borehole can only be extrapolated from core data. By using seismic and electromagnetic cross-borehole geophysical probing, remote probing can be used to sense the region exterior to boreholes. A recent advance has significantly improved the state-of-the-art for defining the ground structure between boreholes. This new procedure utilizes large amounts of data and provides a detailed picture of the subsurface. The data processing algorithms used are similar to those in medical imaging of the human body using x-rays, a science called x-ray tomography. This imaging of the ground is called geotomography, which is a shortened acronym for geophysical tomography. Several examples of geotomography applied to imaging ground structure are presented. Our approach has been to probe the ground with electromagnetic and seismic waves. We map the region of interest with signals transmitted between multiple source and receiver pairs lowered in boreholes on opposite sides of the region (Figure 1). The received signals vary according to the transmission properties of the media

Jan 1, 1979

By Beatriz Cardoso Mendes

O presente trabalho tem como objetivo estudar a viabilidade do uso e a influência do ácido cítrico nas propriedades de pastas e argamassas feitas com cimento Portland CPV ARI, tanto no estado fresco quanto no endurecido. As dosagens de ácido cítrico utilizadas foram 0, 0,4% e 0,8% em relação à massa do aglomerante. Nas pastas de cimento produzidas, foram feitos ensaios de determinação da água de consistência normal e tempo de início e fim de pega. Já nas argamassas foram realizados ensaios de determinação do índice de consistência, densidade de massa, teor de ar incorporado no estado fresco, resistência à compressão axial, nas idades de 7, 14 e 28 dias e análises por meio da técnica de DRX. Os resultados mostram que o ácido cítrico, além de melhorar a trabalhabilidade da massa, contribui para aumento na resistência mecânica nas idades superiores a 14 dias, desde que aplicado em teores aceitáveis.

Jan 16, 2018

By Rogers R, Kinnane T

In a typical open cast mining operation, investigation of how existing truck performance compares with the highest achievable truck performance is largely neglected. This paper addresses this issue by proposing a computerised system that will provide a systematic method for comparing existing truck operational performance to the highest performance considered achievable. Through analyses of existing versus achievable performances, various inefficiencies associated with truck operations can be identified. These inefficiencies could occur due to machine configurations, haul route design and conditions or operator skill level. Remedial action should then be taken in a timely fashion to better manage these factors and to ensure the fleet is always operating at its peak efficiency.

Jan 1, 1994

By John A. Johnson

Tests ere conducted at the Mount Weather testing adit of the 57 Bureau of Mines on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. Equipment Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is mace of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.

Jan 1, 1939

Automated drilling in surface mines is here, it?s successful, and it?s already at work in mines around the globe. Coal, copper, iron and gold mines in large mining countries such as Canada, Australia, South Africa, the United States and Chile are meeting mining objectives previously ruled out as unattainable. Pit Viper automation enables operators to accomplish more objectives safely. Operator assist functions like AutoLevel, AutoDrill, Auto Rod Changer and multi-rig teleremote control are a few of the features mines are using to gain consistent, sustainable productivity.

By George A. Morgan

The successful expansion of crude oil production begun in late 1977, led to promising development of the nonfuel minerals sector. Although actual production of nonfuel minerals was limited both in variety and in percentage of output on a world scale, the potential for expansion with a rapidly developing infrastructure was significant. The energy base was expanding with construction of two new hydroelectric powerplants in addition to the existing plant near Edea. The Song Loulou plant will have a 240-megawatt capacity, and a hydroelectric plant under construction in the northern part of the country by mainland China will have 72 megawatts of installed capacity. Inflation of between 15% and 20% resulted in a real gross domestic product (GDP) of $2.8 billion2 in fiscal year 1980 (July 31 to June 1), up 6% from that of the previous fiscal year. Petroleum became the leading export item in terms of value, surpassing coffee and cocoa exports. Mineral exports as a whole increased eightfold in value, mainly because of oil sales. Oil exports also caused a reduction in the trade deficit by nearly one-third, and the Government expected its 1980-81 budget to be balanced at $1.17 billion. The Port of Douala accounted for about 8 million tons of cargo, or 93% of total maritime traffic for Cameroon. Expansion plans for the port call for an initial increase to 5 million tons, and a cargo handling capacity of 7.5 million tons in 1985 and 10 million tons by 1990. The Port of Victoria will gain importance with the startup of an oil refinery. The country's third seaport at Kribi was used solely for timber shipments, and capacity at the Port was to triple by 1981. The Government operated its own shipping line with six oceangoing freighters. France was the dominant trading partner, accounting for 25%

Jan 1, 1982

By R Castroviejo, E Pirard, L PTrez-Barnuevo

Process mineralogy provides the mineralogical information required by geometallurgists to address the inherent variation of geological data. The successful beneficiation of ores mostly depends on the ability of mineral processing to be efficiently adapted to the ore characteristics, liberation being one of the most relevant mineralogical parameters. The liberation characteristics of ores are intimately related to mineral texture. Therefore, the characterisation of liberation necessarily requires the identification and quantification of those textural features with a major bearing on mineral liberation. From this point of view, grain size, bonding between mineral grains and intergrowth types are considered the most influential textural attributes. While the quantification of grain size is a usual output of automated current technologies, information about grain boundaries and intergrowth types is usually descriptive and difficult to quantify to be included in the geometallurgical model.Aiming at the systematic and quantitative analysis of the intergrowth type within mineral particles, a new methodology based on digital image analysis has been developed. In this work, the ability of this methodology to achieve a more complete characterisation of liberation is explored by the analysis of chalcopyrite in the rougher concentrate of the Kansanshi copper-gold mine (Zambia). Results obtained show that the method provides valuable textural information to achieve a better understanding of mineral behaviour during concentration processes. The potential of this method is enhanced by the fact that it provides data unavailable using current technologies. This opens up new perspectives to the quantitative analysis of mineral processing performance based on textural attributes.CITATION:PTrez-Barnuevo, L, Castroviejo, R and Pirard, E, 2013. New perspectives on quantitative textural analysis, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 191-198 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By C. L. Xiao

With reference to the test report carried out by Guangzhou Nonferrous Metal Research Institute in 1983, the mineral process flow sheet of Yichun Tantalum-niobium mine is determined based on the characters of ores and successful experiences in light of the problems in the existing flowsheet: The ore is desilted before crushing; the primary slime is separately treated; the staged grinding process used while the fine slime is collectedly treated with tantalum and niobium as the main recoveries and lepidolite and feldspar powder as the secondary. The flowsheet is featured by comprehensive recovery, low investment and low energy cost.

Jan 1, 2014

By E. A. Breitenbach

A computer program has been developed to afford rapid and complete quantitative log analysis for exploration and production decisions. The computation consists of automatic selection of tops and bottoms of porous intervals from the digitized data, and then point-by-point calculations within each selected interval. Nearly all log types can be analyzed. This paper presents the calculation techniques found to be appticable to machine evaluation and gives examples of their use. INTRODUCTION As the quantitative interpretation of well logs entails repetitive use of charts and equations, it is natural that digital computer programs would be written. A Universal Log Interpretation Computer Program (ULICP) has been developed to afiord rapid and complete analysis for exploration and production decisions. Application of this program enables the log analyst to: (I) apply rapid quantitative log analysis for exploration and production decisions on either a field, a well or on a single zone basis; (2) apply concepts of interpretation requiring detailed numerical analysis; (3) analyze all porous intervals on each log, rather than a few selected zones, and complete the analysis in less time than previously required. Computations are reported for every digitized point in each zone; (4) use empirical techniques applicable to a given area as an integral part of the computation; (5) experiment with the empirical coefficients and exponents in the interpretation equations to find the best possible solution; and (6) automatically plot both the original and computed data to scales analogous to the field prints. The primary utility of a log interpretation program stems from its ability to do an overwhelming amount of work with very little man-power. If a calculation procedure or thought process can be formalized to the extent that step-by-step logic can be written, a computer program can be developed that follows this logic. The major question is one of economics. A feasibility study of the costs for such a program indicates that digital processing is economical primarily as a means of increasing the productivity of the log analyst. In effect, the probability of missing productive intervals in any well, because of a lack of time to do detailed calculations, is greatly reduced. The nucleus of ULICP is programmed to compute large sections of a suite of logs by selecting zones automatically and then performing all pertinent computations on a data point by data point basis within each zone.'.' An entire suite of logs can be processed in this manner with very little manual intervention. Sufficient programming logic is available so that each log analyst can request computations pertinent to his area. These requests are made by simple additions or deletions of information on the input header cards. Hence, the log analyst is always in complete control of the computation process. The evaluation of a suite of logs requires pre-editing, digitization, computation, presentation of results and interpretation. Work by the log analyst is reqilired only in pre-editing and interpretation. Thus, he is allowed more time for comprehensive interpretation, rather than calculation. For continuity, the discussion of ULICP is organized sequentially: pre-editing, digitization, computation and presentation of results. DISCUSSION PRE-EDITING The extent of pre-editing prior to computation is dependent on the format of the original data. For analog prints, it requires inspection, correlation and editing of the logs, plus the entering of required data an special forms. For digitized data such as magnetic tape field recordings, only the special forms are necessary. The process for analog prints will be given here. The inspection and correlation process involves the selection of sections for digitization and the correlation of the traces to a common depth. To decrease the cost of digitization, traces that exhibit large variations in shale formations can be redrawn to a non-zero baseline. The next step is to enter all pertinent data on the input header cards. The header cards presently used for ULICP are presented as Figs. 1 through 6. Cards 1, 2, 3 and 4 (Fig. 1) are defined as the Main Header Cards. They describe the particular well for output identification and give basic information. Cards 5 through 15 (Figs. 2 through 6) are defined as the Block Header Cards. As such, they define the log types and the interpretation parameters for the block of data immediately following. Cards 1 through 10 are required for every computer run. Cards 11 through 14 pertain only to nuclear logs. Card 11 is required if any nuclear log is supplied, and cards 12 through 14 are required only when gamma-ray, density or neutron log data, respectively, are supplied. Card 15 (Fig. 6) must be supplied when cross-plot calculations are required. Either two- or three-component

Jan 1, 1967

By A. L. Hinde

Ideally, mill circuits should be controlled so that excessive random disturbances are reduced in frequency and amplitude. It is difficult to derive an objective measure of the effectiveness of any chosen control strategy. Often, the response of the circuit to pulse or sinusoidal disturbances is used as a measure of the effectiveness of control, but this is not adequate in many circumstances because such disturbances bear little resemblance to those that occur in practice, and such an approach cannot be easily related to the profitability of the reduction process. A superior approach appears to be the application of the theory of stochastic processes. This theory permits both real process disturbances to be modelled accurately, and useful objective functions for control to be derived. A test of the usefulness of stochastic theory in mill control was made on the gold ore milling circuit shown in Figure 1. This circuit was fed with an ore which had a liberation characteristic such as that shown in Figure 2. It is simple to show that, for such a liberation characteristic, the recovery of valuable mineral will vary as the standard deviation of the particle mass-size distribution varies even though the mean particle mass-size is kept constant. Similarly it may be shown that excessive perturbations in the circulating load in a milling circuit such as that shown in Figure 1 can affect liberation. Figure 3 shows how, as the cyclone feed density increases and the sump water addition decreases at constant sump level, the cyclone operation becomes unstable and the discharge "ropes? with a consequent catastrophic coarsening in product size. By minimising the variance of the circulating load it is possible to reduce the probability of initiating instabilities of this nature.

Jan 1, 1977

By AIME AIME

THE Wednesday morning session was devoted entirely to the consideration of the tentative code for coal mine ventilation. A. W. Hesse is chairman of this subcommittee. E. A. Holbrook presided at the session and assisted by A. W. Hesse and George S. Rice, gave the historical background of the movement for a ventilation code. They stressed the point that this was to be an engineer's code, and that it was hoped that it might serve as a valuable guide to operating companies in securing greater efficiency as well as safety in ventilation. The discussion was continued into the afternoon session, and by adjournment the entire' code had been covered.' Many sections were referred back to the Committee for further study and several new sections were suggested. The various opinions and new ideas brought out during the discussion proved very valuable and. contributed much to the progress being made in the preparation of this code.

Jan 1, 1929

By J. M. Riley

A fluorometric method using morin in an alkaline-buffered chelating solution has been developed by the Bureau of Mines for determining beryllium in ores and mill products. Apparatus for measuring fluorescence intensities of the beryllium-morin reaction is described. Preparation of the sample for analysis consists essentially of digestion with sulfuric, nitric, and hydrofluoric acids, fusion of the residue with sodium carbonate and sodium borate, Solution of the melt with sulfuric acid, and proper dilution. Chemical separation of other ions is usually unnecessary. The method rave reliable beryllium determinations on samples in the 0.01- to 0.37-percent BeO range. The method is particularly applicable to low-grade beryllium ores; however, semiquantitative beryllium determinations have been made on beryl containing 12.0 percent BeO.

Jan 1, 1956

By Thales Lima Da Silva

As cerâmicas avançadas estão em diversas aplicações técnicas devido à possibilidade de melhoria na tenacidade, ao desgaste e corrosão em altas temperaturas. Neste trabalho avaliou-se o aditivo de sinterização Nb2O5 em teores de 0,2%, 0,4% e 0,6%vol. no compósito 98,5% Al2O3 com dispersão de 1,5% de ZrO2 nanométrica. Os pós foram misturados em moinhos de bola e as amostras foram conformadas por prensagem uniaxial. Utilizou-se a sinterização convencional a 1450ºC, 1500ºC e 1550ºC por 1 hora, caracterizando-se a densidade aparente pelo método de Arquimedes e a microestrutura final por microscopia eletrônica de varredura, procurando-se avaliar o efeito inibidor de crescimento de grão da zircônia frente a possibilidade de formação de fase líquida pela adição de nióbia.

Oct 30, 2017