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By T. MacDONALD

ATHOUGH flotation has been a commercial process for over twenty years, the last two years have witnessed a sudden and phenomenal increase in our knowledge of how to separate minerals heretofore not considered amenable to flotation at all. As remarked by Professor Locke in the January issue. "Either commercial or laboratory flotation is reported on zircon, ilmenite, carnotite, kyanite, scheelite, chromite, fluorite, feldspar, cassiterite, wolframite, barite, and clay. Attractive patents on soap flotation are U. S. Nos. 2,000,656 and 2,040.187. A survey by Ralston in the February E. & M. J. adds many other minerals to this impressive list. The simple but pregnant fact is that any mineral can be coated, directly or indirectly, with a water-repellent coating, and since this is true, it follows that any mineral can be floated. Fundamentally, this is no new discovery, where, for instance, is the mineral that cannot he washed from a pair of dirty hands by means of soap and water, given the absence of refractory greases or oils which would have no proper place in flotation ?

Jan 1, 1937

By Thomas J. Pike, Keith G. Kirk, Mark F. Weider, Lawrence E. Welborn

As part of the mine permitting process as delegated by the Surface Mining Reclamation and Control Act of 1977 the regulatory authority must assess the probable hydrologic consequences and cumulative hydrologic impacts of surf ace mining. The U.S. Office of Surface Mining (OSM), in conjunction with Energy & Minerals Technology Assessment and ENCORE Systems Inc., has developed a user friendly groundwater model that is capable of predicting the effects of surface mining on groundwater quality and quantity. The model is a variation of the Prickett-Lonnquist model which has been modified to be specifically applicable to surface mine applications. This model is presently being used by OSM, the states, and industry to determine mining impacts on groundwater resources. The model is designed for use by the hydrologist with minimal computer training. The model accounts for multiple pumping wells, injection wells, multiple mine pits, and mine pit movement through time. This paper presents an example of how the model may be used in permit application review and how the model can be used by industry to simplify permit preparation.

Jan 1, 1983

By Gerry Roblesky

"IntroductionWestar Mining Ltd. is Canada's largest producer of metallurgical coal for the export market. It currently operates two mines, the Balmer Mine at Sparwood, British Columbia producing 6 000 000 tonnes per year and the Greenhills operation at Elkford, producing 2 100000 tonnes per year. Approximately 1600 people are employed between the two mines which operate independently but share common administrative services.Like most mining companies in Canada over the past three or four years, Westar has faced rising production costs along with flat or declining prices and demand for its products. In order to survive under these conditions it has become necessary to strive for decreased costs in any way possible. Over the past two years there has been a widespread introduction of microcomputers across the company. In order to satisfy increasing demand for accurate and pertinent information while at the same time increasing productivity, the microcomputer has become an invaluable tool.This paper describes some of the problems faced by a mine maintenance department in this operating climate and how they were solved with the help of a microcomputer. It also describes some of the problems that may be encountered both with equipment and people and recommends some ways that these might be minimized or avoided. Finally, an assessment of whether or not the move to microcomputers was a current and economical one, and a brief description of future plans and projects is given.The Maintenance OrganizationIn order to appreciate fully the role that microcomputers are playing within the Maintenance Department at Westar Mining, a little background on the organization and operating philosophies is in order. Most of the comments apply directly to the Balmer operations, however, the Greenhills operation is similar in concept.The mine maintenance organization operates on a fleet based concept with these departments reporting to the maintenance superintendent: haulage trucks, shovels and drills, loaders and Caterpillar equipment, maintenance services, and rebuild services.Each of these departments is headed by an assistant superintendent and is responsible for all maintenance on the equipment on the respective fleet. Shift foreman, planners, specialists and clerical staff are assigned to each fleet. A central engineering and administrative group consisting of one engineer and three clerical positions is responsible for maintenance engineering and centralized administrative services"

Jan 1, 1988

By R. J. Brailey

"A USER'S VIEW OF CONVEYOR WEIGH SCALESThe Sudbury Operations of Falconbridge Nickel Mines Limited includes seven mines, three concentrators and a smelter. The flow of ore, concentrates, fuel and fluxes between and within these plants requires measurement for accounting and control. The design, installation and maintenance .of weighing systems falls within the responsibility of the Instrumentation Department of Falconbridge Nickel Mines thus al lowing a common approach to conveyor weighing problems and the benefit of a common spares supply. This paper gives a brief overview of the recent experience with conveyor scales within the Sudbury Operations and discusses the problem areas.GeneralThe best way to establish the total amount of material going to or from a process is with a bucket and a stop watch. Unfortunately the flowrates involved in mining plants make the buckets very large, but wherever it is feasible static weighing is the preferred method of determining total quantity. This applies particularly to batch systems, where the material can be brought to rest long enough to allow a very accurate weight determination. Any form of weighing in motion is susceptible to variations in the forces of the transporting system. A belt scale is affected by its position on the belt, idler alignment, support stiffness, variations in belt tension, material spills and build-up, and a host of other factors all of which require careful consideration in any installation.As with instrumentation applied to any system the plant should be designed to ensure that the best results can be obtained from the equipment. This means getting the scale supplier together with the conveyor supplier as early as possible in the designing of a new plant. Any corners cut in scale installation will be paid for later in poor results and/or increased maintenance."

Jan 1, 1975

By Van Hoorn PD

For the development of BHP's Gregory open cut coal mine in Central Queensland a mini computer was successfully used to assist staff in the evaluation of the deposit and the planning of the mine. The Gregory deposit is essentially a single mineable seam deposit, however the systems developed may be applied to other coal deposits including multi seam occurences. The first phase of the Gregory computer evaluation and planning project involved the establishment of a borehole data base for the storage, retrieval and analysis of both strata and quality data. During the second phase a numeric block model of the coal deposit was created. Using this model reserve calculations were carried out by specifying the area with the aid of a digitizing tablet. The third phase involved the develop- ment of systems to simulate the dragline stripping operations including the rehandle percentage calculation, a dragline production schedule showing coal quantity and quality exposed, and a combined multi dragline operation schedule that can produce figures and graphs for up to 20 variables. A derivative of the operating plan was a programme that gave productioh cost estimates

Jan 1, 1978

By Saulo Brinco Diniz

O presente trabalho buscou explorar a aplicação da nanoindentação instrumentada na caracterização microestrutural e mecânica de materiais metálicos. Para isso foi utilizado um ultramicrodurômetro (Shimadzu, modelo DUH–211S) e um microscópio (Olympus, modelo BX51M) a fim de analisar uma chapa laminada a quente de uma liga de alumínio 7475-T7351. De acordo com algumas das possibilidades apresentadas, pode-se concluir que a nanoindentação instrumentada é uma ferramenta poderosa para a caracterização de materiais metálicos.

Aug 16, 2017

By Lucas Breder Teixeira

O uso de ferramentas de simulação numérica para análise estrutural vem se expandindo nos últimos anos, sobretudo utilizando o método dos elementos finitos. Nesse trabalho são apresentados dois exemplos de otimização de projetos envolvendo componentes de mecanismos de válvula gaveta, realizados pela Magnesita Refratários S.A. Partindo da geometria inicial até o produto final, é analisado como o campo de tensões é adequado a valores admissíveis, conforme modificações de projeto são realizadas. Por fim, é demonstrada a importância desse tipo de estudo para alcançar maior confiabilidade e segurança em projetos mecânicos.

Aug 16, 2017

By R. Adsero

The volume of data produced by operating mines has increased substantially over the last 10 years. However, the volume of data and analytical capability has been negatively correlated to equipment productivity for at least the last seven years. In simple terms, as the volume of data has increased equipment performance has declined. Table (2010) tells us that ?The calamity of the information age is that the toxicity of data increases much faster than its benefits?. More data does not guarantee improving productivity; but more data is also not the cause of declining productivity. Similarly, when equipment performance does start to improve, (it must ? there really is no option if mines want to remain competitive), it will not be the data nor analytics which causes it; it will be the people using the resources at their disposal; including the data. Data and analytics can help if the toxicity of the data can be managed. The simplest form of business improvement using data is benchmarking. The objective of benchmarking is to understand and evaluate the current position of a process in relation to ?best practice? and to identify areas and means of performance improvement. The application of benchmarking involves four key steps: (1) Analyze and understand in detail existing processes; (2) Analyze and understand the processes of others; (3) Compare your own performance with that of the others analyzed; and (4) Design and implement the changes necessary to close the performance gap(s). There are however, many in the mining industries who have shunned equipment benchmarking because they believe that, ?every mine is a pilot?. In other words, the differences between mine operations make comparisons between them of little value. This paper will present a valid approach to benchmarking equipment performance and reliability, accounting for the differences and similarities between operations, producing a result which can be used to add value to mines around the world.

Feb 23, 2014

By C. M. Suhr

n order to validate the borehole analysis valuation procedure commonly used in the South African gold mining industry, a simulated orebody was used to create borehole values which would serve as data for the procedure. After confirming the distribution, calculating the variance size of area relationship, estimating the block variance, and calculating a profit measurement for each set, comparisons were made to the known population parameters. Results show only one overall bias (in the estimation of the lognormal third parameter), which is carried throughout the analysis. The remainder of the analysis is unbiased, validating the procedure.

Jan 1, 1987

By M. Bwalya, L. Mabokela, L. C. Woollacott

This paper presents a study on the ability of the King stratification modelto describe density stratification patterns that are achieved under idealizedconditions. Tests were conducted in a batch jig using artificial particles inseven density classes. All particles in a density class had essentially thesame density, size, and shape. Tests were conducted for particle systemsinvolving from two to seven components. Good agreement was obtainedbetween measured and modelled data to an extent that gave strongendorsement of the mathematical appropriateness of the core equation inthe King model. Somewhat ambiguous results were found with regard toclaims about the independencies of the single experimentally-determinedparameter required by the model.

Jan 1, 2015

By Ning Zhang, Yan Chen, Qikang Yi, Linjian Ma, Guoan Wang

Laboratory tests were performed to explore the effects of frequency on the deformation property of rock salt subjected to cyclic loading under confining stress condition. A two-stage (transient and steady) evolution law of axial cumulative strain was obtained through cyclic stress-strain curves complied from the loci of minimum load of each cycle. The unloading modulus decreases with loading cycles/time as a negative exponential function. The damage of rock salt under cyclic loading is reflected by the degradation of elastic modulus. A unified damage evolution equation considering the effects of frequency and time was established based on the experimental results. A new creep damage model for rock salt was proposed by introducing the non-stationary modular components in Burgers creep equation according to the Lemaitre equivalent strain theory. Comparative study indicates that the new model can accurately describe the creep deformation and damage evolution of rock salt under different loading frequencies. This paper provides a more reasonable model and relevant mechanical parameters for the stability analysis of compressed-air storage cavern in the injection and withdrawal durations.

Jan 1, 2015

By M Stephens, T A. Sutra

Currently, there are several open pit mines with production rates of about 200 000 tpd of ore that are reaching the end of their economic lives. In most cases, the remaining orebody extends to depths greater than 300 m below the pit limit, leaving hundreds of millions of tons of reserves that can only be recovered by means of an underground mining method. One such method used for mass production is block caving. This paper presents a ventilation system for a four-zone block cave mine operation developed on a footprint 1000 m wide and 1200 m long. The system is designed for a mine with a nominal production rate of 120 000 tpd of ore using diesel powered units on the production and reduction levels. It discusses the air quantity requirements for the worst case scenario, which is anticipated to occur five years after the mine has reached its full production capacity. Finally, it summarises the results of computer modelling exercises that were carried out to determine an economic ventilation infrastructure that includes shafts, drifts, main fans, and ventilation control devices.

Jan 1, 2005

By Windsor C. R, Thompson A, Bywater S

A new high tensile strength, steel cable, that may be grouted into boreholes has been developed for use as rode reinforcement. The manufacturing technique produces a birdcage pattern in which the cross section varies along the length of the cable. The load transfer from cement grouts to birdcage cables has been demonstrated in laboratory tests to be better than that of standard 15.2 mm diameter seven wire cables. The manufacturing process also allows for a wide range of capacities which may be specified by design engineers. The various birdcage cable configurations have been applied as rock reinforcement in a number of Australian underground and surface mines.

Jan 1, 1990

The two methods for calibrating the parameters K and (alpha) for use in Gy’s equation for the Fundamental Sampling Error (FSE)–, Duplicate Sampling Analysis (DSA) and Segregation Free Analysis (SFA)–, are described in detail. A case study using identical broken reef material from a Witwatersrand-type orebody was calibrated using the DSA and SFA methods and the results compared. Classically, the form of Gy’s equation for the FSE raises the nominal size of fragments given by dN to the power of 3. A later modification of Gy’s formula raises dN to the power (alpha), the latter term being calibrated with the coefficient K in the DSA and SFA methods. The preferred value of for low-grade gold ores used by sampling practitioners in the mining industry is 1.5. A review of calibration experiments for low-grade gold ores using the DSA and SFA methods has produced values of K that vary between 70 and 170 and values of in the range 0.97 to 1.30. The average value for is shown to be 1, rather than 3 as originally proposed in the classic form of Gy’s equation or the industry-preferred 1.5. It is suggested that for low-grade gold-bearing ores the equation for the FSE should raise dN to a power of 1. Such an equation for the variance of the FSE greatly simplifies the characterization of gold ores, now requiring only the calibration of K for a given mass and established fragment size. The implications of the simplified equation for the heterogeneity test are that, provided the fragments have been screened to within a narrow size range, any particular size will return a value for K that is acceptable for use in the sampling nomogram.

Jan 1, 2017

By T. Kagawa

Ever-increasing demands for non-ferrous metals owing to population growth and improvements in the standard of living in the world, under the constraint of limited availability of natural resources, would easily make us imagine that more efficient and sustainable developments in mining and smelting activities are required in the near future with due consideration for environmental concerns. In order to realize the efficient and sustainable development of mining and smelting activities and operations, the following issues are indispensable: (1) to investigate the up-to-date pollution control technologies of mine and smelter, (2) to promote those technologies, (3) to develop technologies which are environmentally friendly. This paper discusses the recent technologies for environmental conservation/prevention and their diffusion in the world, and also the key technologies required for the most desirable sustainable development.

Jan 1, 2007

For the last 4 years political leaders have found a new subject on which they can safely generalize wihout creating opposition. That sub- ject is commodity prices. Since the four-fold increase in OPEC crude oil prices, public atten- tion has focussed as never before on the subject of commodity prices. To advocate stabilizing com- modity prices is akin to supporting motherhood or peace or better schooling. Everyone gives lip service to the concept that stable commodity prices are desirable. It is easier to state the principle than to achieve it. Prices that are stable in terms of one currency may be clearly unstable in terms of a different currency. This has become a troublesome matter since 1971, when the world's leading trading currencies were set free to float in relation to each other. To illustrate: consider copper prices in the interval between the end of 1974 and the end of 1977. During those 3 years, the copper price in pounds sterling on the London Metal Exchange rose by 25 per cent. During that period, however, in terms of the USA dollar equivalent, the price was unchanged. And during that period, in terms of the German mark equivalent the price shrank by 13 per cent while the Japanese yen equivalent f.11 1k

Jan 1, 1978

The main factors controlling the electro- winning of zinc from impure aqueous sulphate electrolytes are reviewed. Zinc, hydrogen and impurities are deposited at the cathode. The current effic- iency for zinc is increased by increasing zinc/ acid ratio and current density and by decreas- ing temperature; and may be unchanged, increased or decreased by the presence of impurity ions. A qualitative comparison of observed and predicted impurity effects is in reasonable agreement. Quantitative treatment of the effects of impurities and cell additives is not available. A tentative explanation of the time dependence of current efficiency in the presence of some impurities is provided. The forms in which impurities are deposited is substantially unknown. Impurities may be classified according to the extent of cathodic deposition. Procedures for control of cathodic deposition of impurities are outlined. The main anodic reactions are the forma- tion of oxygen, manganese dioxide and sulphuric acid. Minor reactions include the oxidation of lead, silver, cobalt and chloride. The site of the anodic reactions and the reactions generat- ing manganese dioxide are uncertain and may change with time of operation. The anode behaves crudely as an oxygen electrode with

Jan 1, 1977

By JIACHENG XIE, Juanli Li, Wenyong Du, Tao Cui, Mengyao Dong, Pengfei Huo

The study proposes a dynamic path planning method for mining equipment based on spatial kinematics and real-time correction of coal-rock state identification. The method integrates real geological data and equipment operation information to improve the autonomous cutting of fully mechanized mining equipment.

May 1, 2023

By JIACHENG XIE, Juanli Li, Wenyong Du, Tao Cui, Mengyao Dong, Pengfei Huo

The operation of intelligent coal mining in complex geological environment is still unable to realize automation. In order to realize the autonomous cutting of fully mechanized mining equipment and improve coal production, a mining and transportation equipment dynamic advancement path planning method based on spatial kinematics coordinate deduction prediction and real-time correction prediction of coal-rock state identification of equipment cutting current index are proposed. Firstly, the spatial motion law of the mining and transportation equipment is analyzed, and the mathematical model of the spatial motion of the mining and transportation equipment is established. The relationship between the adjustment of the shearer rocker arm and the pose change of the scraper conveyor is determined, and the coordinate deduction model of the spatial advancement position of the equipment is determined, which provides a theoretical basis for the advancement path planning of the mining and transportation equipment. Then, on the basis of the mathematical model construction, combined with real geological data and equipment information, the three-dimensional dynamic planning of the advancement path of the mining and transportation equipment is carried out from the two dimensions of the horizontal advancement direction and the shearer walking direction. At the same time, the relationship between the cutting current index of shearer and the state recognition of coal-rock mass is analyzed, and the coal-rock mass state identification of cutting current and the adjustment of rocker arm model is constructed, and the real-time dynamic correction of three-dimensional path is carried out, so that the planned path can better adapt to the sudden change of real geological environment. Then, using the unity3d virtual reality technology, a simulation system for the horizontal advancement path planning of the virtual mining and transportation equipment is constructed, which simulates the real advancement operation process of the mining and transportation equipment and conducts advancement training. Finally, the dynamic advancement scheme update prediction based on the existing actual cutting but ahead of the actual cutting is realized in the virtual scene, and the optimal scheme is transmitted into the existing prediction cutting system to guide the actual physical equipment mining. The path planning method can control the coordinate position error of the advancing cutting path within 15 mm, which provides ideas for the research on the advancing path planning of fully mechanized equipment.

Nov 22, 2022

By John V. Beall

GOING west from Denver on Route 6, the direct road to Grand Junction, one gets the first glimpse of mining a few miles east of Denver near Idaho Springs where the workings of defunct gold mines are visible on the sides of mountains along the highway. One enterprising company is turning a profit by showing tourists through the mine and mill and then selling them gold samples on the way out. We have always known that mining people are ingenious, but this proves it. About five and a half hours fast driving west from Denver brings one to Rifle, Colo., which is the site of the oil shale mine, retorting plant, and refinery of the U. S. Bureau of Mines. As you drive up to the mine, you can see a portal high on the face of the cliff in front of you where the mine surface plant literally hangs by its toenails. Below, the retorting plant and refinery gleam in the sunlight. Up at the mine, Fred Wright will show you how the oil shale is extracted in two benches (a third bench would be used for commercial mining) by the room-and-pillar method. In mining the top level, an underground crew of thirteen men have been able to produce 1500 tons of shale in each eight-hour shift. To do this, the mine is thoroughly mechanized. The mining method is de- scribed in the September issue of Mining Engineering.

Jan 1, 1949