Search Documents

By D. R. Maneval

The Surface Mining Act of 1977 required a study by the National Academy of Sciences regarding the special mine reclamation requirements of Alaska. The status of mines operating and planned in Alaska will be presented. New mines opening in Alaska must establish a baseline inventory of plants and animals in the mine site area as well as determine pre-mining air and water quality. Current work in these areas will be summarized. Reclamation practices in Alaska and other Arctic countries as practiced currently will be described. A summary of current research in Alaska dealing with revegetation on surface mined lanais, re-establishment of animal populations, and water treatment processes necessary in this pristine environment will be discussed. Included will be future predictions of the direction of mine reclamation in Alaska as more mines enter the industry.

Jan 1, 1984

By Timothy D. Dreger

In the spring of 2009, Suncor Energy Inc. technical personnel saw an opportunity to improve planning 0and mining of overburden material in order to address aggressive construction goals and increased mining complexity. By tying together current and historical equipment performance, geological model information, and material observation in the field new operating elevations for the shovels were developed. At the same time, methodology of recording and reporting overburden movement through the Modular Mining DISPATCH system was changed. The result of this first stage of improvements was an increase in construction-grade material available at the face. The personnel involved realized that other opportunities were available to build on the initial successes and establish processes that would stand up to attrition and experience levels. A cross-functional technical team was assembled to identify ways of further improving workflows around overburden mining. Some of the opportunities realized include greater alignment between planning, reporting and operations as well as development of reporting tools that help steward Mine Operations to the plan. All of which have resulted in Suncor meeting or beating its forecast overburden targets. The cross-functional technical team continues to seek out new and better ways of doing business so Suncor can continue to deliver on its commitment of outstanding performance and results.

May 1, 2011

By R. Velkova, D. Bojinova

The objective of the present investigations is to establish the effect of the preliminary mechanical activation of phosphates on the degree of phosphorus extraction by bioconversion of Bulgarian and Tunisian phosphates using A. niger fungi and T: thiooxidans microorganisms. The influence of the phosphate concentrations, the type of the nutritive medium and the incubation times on the process of biological mobilization of the phosphates was studied. When the concentration of phosphates in the medium is twice as high, an equal and/or higher degree of phosphorus extraction can be achieved through the bioconversion of mechanically activated phosphates compared with non- activated phosphates under similar conditions. A maximum degree of 90+% phosphorus extraction in utilizable form was achieved at definite conditions.

Jan 1, 2002

By Christopher M. Rule, Martyn P. Hay

"A methodology was developed in the mid-1980’s to predict plant performance from standard laboratory flotation tests. The methodology incorporates a flotation simulation program “SUPASIM” which translates flotation performance from bench-scale tests to full-scale plant. The technique is based on a simple, empirical kinetics model, and is tailored for use by the practical metallurgist. Kelsall’s unmodified equation incorporating two rate terms describing slow and fast floating components is used as the basis of the method. The flotation behaviour of an ore is described by a set of numbers, which can be compared in the evaluation of ore types, mineralogy and operating conditions. In so doing a precise relationship is developed between metallurgical performance in terms of grade and recovery and flotation kinetics.To date the performance of more than 20 flotation plants has been predicted, encompassing copper, lead, zinc, nickel, phosphate, pyrite, graphite, cassiterite, platinum and various slags. In three cases, plants have treated more than one type of ore. The method has successfully been used to predict and design four flotation plants using data generated from bench-scale laboratory flotation testwork. All have since been commissioned, and have performed as predicted. In the last year alone it has been used to drive flowsheet development for at least seven new plants in South Africa and the Americas. It is also being used to assist in the optimisation of existing operating plants."

Jan 1, 2003

One of the strategies introduced within Pasminco Mining to survive low commodity prices is to formally implement a `Quality Education System'. The net result has been a consistent approach to quality within and across mine sites. This `quality system' has been adopted in the technical computing environment and the immediate benefits have been: ò A clearer understanding of the systems, processes and relationships that involve technical computing. ò A re-focussing on customer (user) requirements. ò Inclusion of managers as customers with their own requirements of performance and quality, in addition to access to Executive Information. ò New ways to measure the `performance' of a technical computing environment which includes using maintenance costs. Observations are that there is an overlap between `traditional' information technology (IT) methodologies and quality systems being put in place in the broader workplace. This overlap is most apparent in the area of analysing customer requirements. In the IT environment customers are viewed as users, and their requirements determined by undertaking a requirements analysis. A data flow diagram traditionally used in the IT environment and not as a tool in quality systems, has been used in a novel manner to help identify the customers of the technical computing department. It has also been useful in illustrating the work processes and relationships between the entities in this diagram and in directing the future initiatives needed to fulfil the customers' changing requirements.

Jan 1, 1995

By Min-Yuan Cheng

Landslides not only cause interruption of road traffic but also cause damage to passing by vehicles and injure people in Taiwan. Due to the budget limitation of government, the overall assessments and maintenance of all road slops cannot be fulfilled. Priority of road for maintenance is a crucial task for road maintenance department to identify. The purposes of this research are to develop an assessment method for the landslide risk and to make strategies to maintain or repair the slopes along mountain roads. To aim both needs to take into account the environmental conditions of the slopes, the engineering measures for stabilizing road slopes, the transportation issues, and the human concerns when dealing with the slopes maintenance along the mountain roads. This study firstly establishes the Landslides Damage Risk Evaluation Model (LDREM) to calculate the risk of slope failure, considering the probability of landslides, temporal probability, spatial impact probability, the value of human life, transportation time increased, and travel cost due to detour etc., and then the loss of life and transportation can be calculated. Secondly, based on the value of risk and the risk evaluation, considering the risk acceptance criteria for loss of life could provide assistance for road maintenance department to determine the priority of mountain roads for maintenance.

Aug 1, 2013

By Gilbert P. Moore

Production in the Argentine in 1930 amounted to 1,415,099.7 metric tons, which converted into barrels of 42 gal., using the factor of 6.29, amounts to 8,909,773 bbl. This is a decrease of 481,613 bbl. from the 1929 production, which was 9,391,386 bbl. The production for 1930 was divided among three fields, as shown in Table 1. Table 2 covers Table 1.—Argentine Oil Production, 1930, by Fields Barrels Comodoro Rivadauia District Government........................................... 4,547,670 Railways Co........................................... 1,314,358 Astra-Eastern......................................... 1,016,024 Anglo-Persian......................................... 365,021 Solano Co............................................. 24,613 Dutch Shell........................................... 6,963 7,274,649 Neuquen District Government........................................... 569,245 Standard Oil-Argentina................................. 659,551 Astra-Eastern......................................... 8,234 Challaco Co. (Sol)...................................... 121,598 1,358,628 Salta District Government........................................... 90,576 Standard Oil-Argentina.................................. 185,920 276,496 8,909,773

Jan 1, 1931

By R. D. Corrans

"Africa is endowed with a number of the world's giant ore deposits which have contributed significantly to the development of their host countries. Mineral exploration has a long history in the continent, but mining on an unprecedented scale took off during the latter part of the 19th century, accompanied by the development of lines of communication and other infrastructure to service the major mining centres.The ""Winds of Change"" which swept Africa in the 19505 and 1960s brought in new styles of government and economic management to a number of regions, often with demise of economic viability and infrastructure. In recent years, with the end of the cold war, collapse of communism and changes in South Africa, new opportunities for mineral exploration are opening up rapidly in Africa. However, due to the large cost, long lead-in time, and high risk of developing new mineral ventures in the continent, it is necessary for the host countries to draft realistic and favorable mineral laws and fiscal codes in order to attract, and not deter, potential mineral investors. There will be an on-going role in mineral exploration throughout Africa for the artisanal miner, the smaller entrepreneurs and mining companies, exploration aid programs funded by the developed countries through African governments, as well as the major mining houses who have the resources to develop larger viable mineral deposits."

Jan 1, 2008

By Jensen B

The approach of using the Coward Triangle for the analysis of flammable mine gas mixtures has been examined for its application, to the flammability of coal dust/gas/air mixtures. Explosible lean limit and rich limit concentration data for dust/methane/air mixtures are examined and illustrated using co-ordinate geometry. It is concluded that a three-dimensional envelope representing hybrid explosible mixtures can be drawn. The dimensions of this explosive zone will vary with the characteristics of the coal dust and the gaseous composition of the mine atmosphere. Further research is needed to establish these dimensions for important mined seams.

Jan 1, 1994

By Y. Mishima, R. Shiromizu

THE equilibrium y phase in Cu-Be alloys forms by discontinuous precipitation, the new phase nucleating at the grain boundaries and growing into grains on both sides of the boundary. When the alloy is aged above 500°C, however, growth may take place into only one of the grains.1'2 In A1-Ag alloys it is known that the precipitate has the same orientation as the grain in which no growth takes place.3, 4 This was confirmed in the present investigation on a Cu-Be alloy. A Cu-1.79 wt pct Be alloy was solution-treated at 810°C for 2+ hr, quenched into water at O°C, and aged at 600°C for 1 hr in a salt bath. The specimen was thinned by chemical polishing and electropolishing at room temperature in a solution of H3PO4 saturated with CrOs. The foil produced was examined in a JEM 150 electron microscope operating at 150 kv. Fig. 1 shows precipitates growing on only one side of the grain boundary. The black platelike precipitates were identified as the y phase. Electron dif-

Jan 1, 1969

By Jim V. Rouse

In situ mining and dump leaching has been practiced for years. Recent environmental concern over conventional mining and milling techniques has rendered in situ mining more attractive. While there are many environmental advantages to in situ mining, there are disadvantages which, if ignored, can lead to environmental damages, followed by stringent control. The environmental advantages and disadvantages of the various types of in situ mining operations are discussed. Current legislation and regulations governing in situ mining are cited, together with a suggested program of environmental monitoring designed to protect the mining company as well as the environment. Suggestions are made for possible solution of existing pollution problems associated with previous mining activities by heap-leaching techniques. Present and indicated control of subsurface injection is traced, because of the many similarities in philosphy and monitoring requirements to in situ mining.

Jan 1, 1974

This paper explains why the valuation of mining assets is often a very different exercise from the valuation of the shares in the mining company which owns those assets. The fundamental reason for this is that mining assets, and the shares of the company which owns those assets have different risks. In order to properly value mining securities it is essential to: ò ensure all the different risks and other factors which impact on the value of the mining assets and the value of the shares are taken into account; and determine the extent to which the different risks and other factors are addressed in the value of the mining assets and the value of the shares so as to avoid double counting or not counting at all. If the alternative, but far from consensus, view is accepted that the correct valuation methodology to apply to shares in mining companies should be based on option pricing theory then conventional valuation practice of both mining assets and shares in mining companies will need to be fundamentally reassessed.

Jan 1, 1994

By S. Naidu, J. Kelley, Roger Amato

The Alaskan Continental Shelf covers 76 % of the total shelf area of the United States. There are a lot of potential gravel deposits in the Alaskan offshore region. The gravel resources are currently not feasible for mining for the following reasons (U.S Congress, 1987): 1. Much of the glacial gravel is poorly sorted. 2. Gravel deposits are overlain by sandy and muddy layers. With the sea level expected to rise 70 cm in the next 100 years (Intergovernmental Panel on Climate Change, IPCC, 2001; Day, 2004), erosion of coastlines will be a major problem not only in Alaska but worldwide. Hence beach nourishment projects designed to minimize erosion will require large volumes of sand and gravel. Offshore areas will become a logical source for the fill material because of their proximity and ready availability. It is likely that future supply of coarse aggregate in Alaska may involve exploitation of marine deposits. The Chukchi Sea is a potentially favorable region for this type of mining because of extensive deposits of paleo beach and other relict gravel found in the near shore region (Stauffer, 1987). However a systematic analysis of potential gravel resource has not yet been conducted and it is the purpose of this research to estimate the size, extent and variability of gravel material that may be available in the continental shelf, offshore Kivalina.

During conventional eddy current separation, a repulsive force is applied to metallic particles by placing them in a rapidly changing magnetic field generated by a spinning magnetic rotor carrying an arrangement of alternate magnetic poles. This method works effectively for larger non-ferrous metallic objects, such as aluminium cans, but as the metallic particles become smaller, the bulk repulsive force on the particles is increasingly replaced by a rotational torque. Therefore, for small metallic particles it makes sense to use particle rotation, rather than particle repulsion, to effect a separation. Eddy current separators using particle rotation are similar in construction to present separators, but are designed to produce a rotating field of essentially constant angular velocity and field strength. Practical and economic particle rotation eddy current separations are possible down to particle sizes of about 200 ¦m, but separations, at probably uneconomic rates, can be carried out on particles as small as 50 ¦m.

Jan 1, 2000

By Chi-Yuen Wang, Chaw-Long Chu

The time-dependent volumetric constitutive relation for a San Andreas fault gouge and a consolidated kaolinite are experimentally determined at confining pressures to 200 Mpa, under creep condition and at ultrasonic frequency. At any given pressure, the bulk modulus determined at 1 Mhz frequency is identical to the "elastic" modulus determined at a stepwise change of pressure. After the pressure change, there occur a time-dependent change of volume and thus the effective bulk modulus. The constitutive relations may be modeled by a standard linear viscoelastic medium with pressure-dependent moduli and viscosity. For the San Andreas fault gouge, viscosity increases from 2x10 13 poise, at 17 Mpa, and 10 14 poise, at 100 Mpa. For kaolinite sample, the corresponding values are 3x10 12 poise and 10 13 poise. These results imply that both stress and pore pressure in fault zones may show time-dependent variations in response to a change of state of stress, such as that occurring after an earthquake.

Jan 1, 1982

By J. Derwin King, Harrison R. Cooper

Applications of nuclear magnetic resonance (NMR) offer possibilities for on-line sensing of the concentrations of several elements in flowing sample streams. In addition to hydrogen, these elements, generally of low-order atomic number, include aluminum, phosphorus, fluorine, sodium, boron, and lithium contained in minerals having commercial importance. Many such elements have been difficult or impossible to successfully measure on-line using the more familiar X-ray fluorescence and neutron activation analysis techniques. The availability of practical on-stream analysis methods is essential to applying advanced controls to processes incorporating these elements. On-stream NMR instrumentation has been demonstrated in the past for several process applications including, as an example, coal flow and analysis; and the technology has recently been extended to the measurement of phosphorous BPL in Florida beneficiation plants. The technique involves simultaneous sensing of proton (hydrogen) and 31P intensities to provide data for continuous calculation of BPL in the phosphate through calibration to volume fractions of water and solids. Initial operating results are described using the PhospholyzerTM on-stream phosphorous analyzer designed for plant application.

Jan 1, 1990

Computational techniques in determining particle size distributions after blasting is getting wide acceptance. A well known approach to extract this kind of information from digital images is edge detection. The number of edge points on a given image increase proportional to the increase of the particles on the image. By selecting a conveniently smooth threshold, counting the signed edge pixels may be a suitable metric further used to quantify the number of particles in the image. Here we propose an image processing algorithm together with Adaptive Neuro Fuzzy Inference System (ANFIS) to efficiently count the rock particles with various sizes on a given surface. To determine a suitable approximation for a mapping between the number of edge pixels and the number of particles, ANFIS is a suitable tool. As a trainable classifier ANFIS proved itself as being better efficient approach than other well known multilayer perceptron classifiers. ANFIS is trained by using convenient training data pairs previously experienced from empirically counted sample images. When given a new image containing the particle information of selected surface, the hybrid neuro fuzzy image processing approach provides satisfying performance on counting the correct number of particles up to the given scale of sizes. In this paper an experimantal study for assessment of particle size using ANFIS is presented.

Jan 1, 2004

By David H. Y. Tang

The reinforcement mechanism of suspension effect is analyzed based on beam-column theory. The equations of the maximum bending stress, deflection and transferred bolt load for the bolted roof strata are derived. In the analysis, the bolt load is assumed to be point load and the horizontal stress is uniformly applied to each stratum. The reinforcement mechanism of friction effect is also analyzed. The major function of roof bolting in this case is to create the friction- al resistance by tensioning the roof bolts, thereby the individual thin strata are "welded" into one single thick stratum. Based on the results, equal spacing of roof bolts is used in the suspension effect while for friction effect, the bolts should be spaced based on equal shear force concept. The design nomographs for the proper bolting pattern and bolt tension of mechanical roof bolting systems are presented for practical applications.

Jan 1, 1984

By Bruce A. Kennedy

The long awaited new Mining Engineering Handbook is taking shape under the leadership of A. B. Cummins, Chairman of the Editorial Advisory Board for the SME Mining Engineering Handbook, and Ivan Given, Editor-in-Chief. The last Mining Engineers' Handbook, the Peele edition, published by John Wiley and Sons, was last revised in 1941. This book was and still is a virtual mine of information although a good deal of its content, especially the cost tables, is becoming rather antiquated. The new one-volume work will contain approximately 1600 pages and be divided into 36 sections. A brief summary of the sections follows: The Place and Contribution of Mining, Mining Costs: Mining Geology-Minerals and Mineral Deposits; Minerals Discovery-Prospecting and Exploration Methods and Equipment; Site Exploration and Selection; Minerals-Mining Design; Soil and Rock Mechanics; Design of Excavations; Opening and Development: Underground Mining Systems and Equipment; Roof and Ground Control; Groundwater and Groundwater Control: Open-Pit and Strip-Mining Systems and Equipment: Underwater and Ocean Mining; Fragmentation-Cutting, Drilling, Blasting; Underground Haulage: Hoists and Hoisting Systems; Surface Haulage, Hoisting. Lowering Pumping and Drainage; Ventilation: Mine Surveying; Ore and Coal Processing; Mill Design; Industrial Minerals-Specifications and Markets: Power; Maintenance plant and Equipment; Supply Service; Health and Safety; Reclamation and Surface Restoration: Administration and Management; Operations Optimization (Systems Engineering) : Mint, Costs and Control: Mine Examination. Valuation. Reports; Engineering Terms: and Consulting Engineering.

Jan 1, 1970

The conservation movement, initiated during the time of Gifford Pinchot and Theodore Roosevelt, has gradually taken hold of the popular imagination of the American people; and today, although it is little understood, it is an accepted doctrine. But the subject should not degenerate into cheap and misleading publicity. In the wise development and use of human and material resources lies the answer (Fig. 4). Conservation does not mean the parsimonious and misguided avarice of the miser, but the prudent and intelligent use of all types of resources, and the opening of a way for the use of those potentialities that lie just beyond the horizon and wait for man's constructive efforts to make them available. Conservation consists essentially in not emptying the pools of primary wealth before the minds of men, guided by ingenious research, have found ways to replenish them from sources as yet untapped. To advance successfully along this path, man should be guided by science and by a decent understanding of his obligations to his fellow man and particularly to his children and his children's children. Two pathways branch from this general road. One is the restraining of those spendthrifts who would throw away our national heritage for the sake of a cheap and irresponsible enjoyment of the present. Conservation in the generally understood sense usually has meant

Jan 1, 1950