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By J. W. Eckerd, W. S. Sanner, P. L. Woolf, R. E. McKeever

The Bureau of Mines experimental blast furnace was operated successfully with anthracite metallurgical briquets . Tuyère pressures were higher and more erratic than for operations using coke , and furnace " hangs " occurred more frequently . Higher hot - blast temperatures were required to maintain the quality of the metal . By using higher hot blast temperatures , the fuel and production rates and slag volumes were comparable to those obtained for all - coke operation . The anthracite metallurgical briquets exhibited excellent mechanical strength and descended through the shaft of the furnace with little breakage or reduction in size .

Jan 1, 1964

By C. Bazin, D. Hodouin

"A flexible model involving perfect mixers, stagnant zones, plug flow, material bypassing and recycling zones has been developed for interpreting mixing phenomena in mineral processes. The mixing properties are described by the residence time distributions which can be subsequently interpreted by the flexible model. User-friendly computer programs (for 1MB-PC or compatible) have been developed for simulation and modelling of RTDs using the proposed model. Seven mineral processing case studies are discussed in terms of experimental procedure, model calibration results and application of the estimated mixing model to process modelling, diagnosis, and performance evaluation. IntroductionIn any mineral processing plant there are continuous-flow machines that transform or separate the ore components. Grinding mills, flotation cells, conditioning and leaching tanks are examples of such machines. The performances of these vessels or reactors are controlled by the rate at which the reaction proceeds and the time spent in the environment where the reaction occurs. This paper deals with the latter aspect of mineral processes operation.Since most of the reactions occurring in mineral processing units are time dependent, knowledge of the residence time of the material in process vessels is important for modelling and diagnosis purposes. Due to the random mixing phenomena involved in the process equipment, there is a distribution of the residence time of the ore particles and the fluid in the vessel. The probability density function E(t) that a micro-element of the material flowing through a processing unit stays a time t in the vessel, is the residence time distribution (RTD) of the corresponding component."

Jan 1, 1988

By Martín Antonio Encinas‐Romero, Patricia Guerrero‐Germán, Jesús Leobardo Valenzuela‐García, José R. Parga‐Torres, María A. Bracamontes‐Landavazo, Agustín Gómez‐Alvarez

A study was carried out to process a sulfide mineral concentrate from Norwest of Mexico containing 97 g/t Au, 0.15% Cu, and 15% Fe. An oxidative acid pretreatment was investigated using ferric sulfate as oxidant, followed by leaching of gold with sodium cyanide. Scanning electron microscopy, SEM-EDS, and X-ray diffraction, XRD, the analysis confirms the presence of quartz and pyrite species. First, a leaching was carried out without pretreatment, at ambient conditions, T = 25 °C and P = 1 atm, obtaining only a 45.2% gold extraction. Once the presence of Fe and Cu sulfides had been confirmed, the Eh-pH diagrams were constructed for the Fe-S-H2O and Cu-S-H2O systems, where it is appreciated that pyrite and chalcocite can dissolve with high oxidation potentials and forming sulfur, oxidizing to sulfate at highly acidic conditions. The oxidized concentrate was neutralized and adjusted to pH > 10.5; it was leached at ambient conditions, at different particle sizes, 44, 37, and 26.5μm, achieving an Au extraction of 75% using a concentration of 0.5% NaCN, 26.5μm particle size, 20% solids, and P = 1atm. Then the oxidized material was subjected to different temperatures, 25, 50, and 70 °C, under the same conditions and obtaining Au extractions up to 92% at 70°C. Additionally, the leaching process was compared using an autoclave reactor at moderate pressures, obtaining an increase in the extraction of Au up to 98% in 2 h, at T = 70 °C and P = 0.62 MPa.

Jan 23, 2022

Railway cuttings require the highest care in design and construction, as the pro- bability of failure concept does not allow any risks to be taken with hundreds of lives being dependent on continued stability. The usual geological influences on stability such as bedding dip and faulting are often discus- sed, but other major problems may come from the presence of sheet joints, cross joints differential weathering and seasonal or daily changes of ground water level. The design of rail cuttings has taken little note of the problems imposed by cons- truction methods, and low cost quarrying methods may seriously weaken a designed shape. The presence of berms and drainage ditches is often difficult to achieve as blasting imposes cumulative stresses and jointing on rocks. Contractors face difficulties in bidding extensive rock cuttings as variations in rock properties are often concealed and overshoot- ing the toe of a batter can easily occur. Modern blasting methods offer some solutions, but the best guide to safe successful cuttings is extensive investigation and the continued involvement of engineering geology at the stages of feasibility, design, construction and maintenance. Two case histories show the influence of folding, faulting and construction methods in the case of slope failure and slope stability.

Jan 1, 1979

By Keith Heasley

As part of the initial investigation and validation of a new boundary-clement formulation for stress modeling in coal mines. the underground stresses and displacements at two multiple-seam coal mines with unique stress problems are modeled and predicted. The new program, LAMODEL, calculates stresses and displacements at the seam level and at requested locations in the overburden or at the surface. Both linear elastic and non-linear seam materials can he used: and surface effects, multiple seams, and multiple mining steps can be simulated. In order to most efficiently use LAMODEL for accurate stress prediction, the program is first calibrated to the site-specific geo-mechanics based on previously observed stress conditions at the mine. For this calibration process. a previously mined area is "stress mapped" by quantifying the observed pillar and strata behavior using a numerical rating system. Then, the site-specific mechanical properties in the model are adjusted to provide the best correlation between the predicted stresses and the observed underground stress rating. Once calibrated, the model is then used to predict future stress problems abead of mining. At the two case study mines, the calibrated models showed good correlation with the observed stresses, and also accurately predicted upcoming high stress areas for preventive action by the mines.

Jan 1, 1998

By A. L. Mular

Some specific cases of the collection of data from industrial grinding and classifying operations, and the development of models from the data so obtained, will be described. The problems encountered, the effort involved, and the value of the derived models in improving the plant efficiencies will be discussed and documented where possible.

Jan 1, 1971

By G. L. Simmons.

Many large. low-grade (refractory) sulfide gold resources exist in Nevada and other parts of the world that are not amenable to concentration by conventional flotation practice, Over the past several years Santa Fe Pacific Gold (SFPG) has investigated flotation process options to economically treat low-grade refractory resources of this type at Lone Tree and Twin Creeks. Conventional flotation technology applied to the original high-grade gold resources at Lone Tree and Twin Creeks was initially unsuccessful. Review and analysis of auriferous (gold-bearing) iron sulfide mineralogical characteristics and flotation chemistry provided a fundamental understanding that led to the development of a new flotation process that SFPG refers to as N2TEC. This paper discusses the development of this technology and compares N2 TEC results with conventional flotation practice.

Jan 1, 1997

By Sakellariou M., Ferentinou M.

Determination of the nonlinear behavior of multivariate dynamic systems often presents a challenging and demanding task. Therefore, complex geomechanics systems are an ideal area for the application of intelligent methods. Often the physical problem is controlled by nonlinear equations, conveying to the use of neural networks. Hudson, (1992a), aiming at efficient engineering modelling and design, introduced and developed Rock Engineering Systems (RES) approach, through the implementation of generic interaction matrix GIM. This approach has been used for a wide variety of rock engineering and other problems, resulting in many case studies available, which illustrate the application of RES to rock engineering problems. Considering the spectrum of the coding methods for the Generic Interaction Matrix, we suggest an objective coding approach. Among the five proposed coding GIM methods, the coding method according to the slope of Pi and Pj relation is relatively accurate, but it might be difficult or impossible to establish or estimate the exact relation of Pi vs Pj for most of the variables involved within a rock engineering system. Self organising maps, are a special type of unsupervised artificial neural networks, which can learn from complex, multidimensional data, and transform them to visually decipherable clusters. The proposed, coding of the GIM, is performed through the combined use of scatter plots produced through, (SOM), and the coding according Pi vs Pj slope. Naghadehi et al., (2013) constructed a database of worldwide experience, in open-pit mine slope stability, the selection of the principal factors was based on Hudson (1992a) who proposed an ‘atlas’ of factors affecting the stability of rock slopes. Slope classification was performed according to status of stability. The rating of the GIM matrix was completed, coupling scatter matrix produced by SOM training, and Pi vs Pj slope plot. Results refer to the identification of clusters, according to status of stability within the original multivariate data set, and the rating of the principal factors according to the dominance and interaction intensity within the open pit mines RES.

Jan 1, 2015

By P. B. Altringer

The Bureau of Mines conducted laboratory tests to develop a process for recovering a marketable grade of tungsten from the brine of Searles Lake, Calif. The brine contains only 56 parts per million of tungsten (70 ppm WO3). Using ion exchange resins synthesized by Bureau chemists, 98 percent of the tungsten was extracted from the brine and 92 percent of the tungsten vas recovered as a marketable iron-tungsten concentrate containing 44 percent tungsten as tungsten trioxide. Although major technical problems have largely been resolved, research is progressing to escalate testing in a process investigation unit to provide more reliable data for an economic appraisal.

Jan 1, 1978

By Dominique Francois-Bongarcon

The rational and optimal determination of the design of a mining exploitation is a very intricate and difficult problem : the parameters are numerous, some technical, some economic or technico-economic which cannot be fully controlled; beside, deposits are estimated from very limited information and the choice criteria are not always quantitative, the economic context has to be anticipated by several years, and even the technological limits can change tomorrow. So, although very clever and performing numerical algorithms have been developed in recent years for open-pit design, we consider that this problem has not really been solved satisfactorily until now. The reasons are that people have concentrated their efforts on informatical algorithmical problems, and have assumed that the technical and economical data are well defined at the time of the study, which is generally not true. In particular, the mere fact of assigning dollar- values to blocks in order to maximize the total cash-flow is generally unrealistic because of the uncertainty of the data used. Consequently, the significance of the unique pit obtained as a result of these algorithms is questionable.

Jan 1, 1981

By Robert S. Becker

The results of a laboratory investigation of coal cutting mechanics and noise is presented. These experiments were performed using a linear cutting apparatus that operates over a broad cutting speed range. The influence of several coal cutting parameters on the noise, force, productivity, and specific energy associated with linear cuts is ascertained. Some basic theoretical aspects of coal cutting mechanics and noise generation are discussed, and the results of the laboratory experiments are used to Formulate analytical models of the coal cutting forces and noise. The analytical model For coal cutting noise is then generalized to account for the more important effects of rotary cutting. Based on the generalized model, an estimate of the sound pressure level at an operator's position is made for a typical continuous mining machine. It is concluded that by employing linear rather than rotary cuts, using deeper depths of cut, slower cutting speeds, and more efficient cutting tools, it is possible to reduce the level of coal cutting noise, as well as Provide benefits to other important areas of underground health and safety.

Jan 1, 1980

By L Bertoss, D Carvalho

In the last decade, the use of advanced implicit modelling software/algorithms in mineral resource workflows has become a best practice in the mining industry. In most cases, these workflows can easily replicate the level of detail of explicitly modelled geometries, even for very complex deposits. These techniques are flexible and can produce fast results since software is responsible for generating 3D surfaces and solids based on geological and interpretation data. Nevertheless, depending on how unique and complex some deposits are, intense manual editing and input are required to honour the geological context and produce the desired outcome. The current geological modelling workflow at George Fisher Mine (GFM) is based on the semi-automatic built-in tool that generates stratigraphic sequences (stacked lithology layers) based on logging and mapping data. This tool (stratigraphic sequence from Leapfrog Geo™) works for the majority of areas in the mine but fails to capture observed mineralisation pinch-outs in operational areas and at extrapolated boundaries of the deposit. These pinch-outs have the potential to negatively impact grade forecasts if not resolved manually. Using built-in software tools only, the alternative for a more accurate model is to generate each individual layer and adding tens of thousands of manual interpretation points to honour pinch-outs (based on the amount of existing drilling in the mine and number of layers). This approach would require an estimated minimum of two to four years of a full-time employee (FTE) to be exhaustively completed. This study presents an automated approach to generate pinch-out points using a set of Python scripts that only take a few minutes to run. The newly generated points are then combined into the commercial software workflow as interpretation points, honouring observed pinch-outs. The remarkable time difference between approaches removes chance of manual errors and allows mine geologists to spend valuable time in validation and testing of scenarios, ensuring they are more representative of the deposit’s geology.

May 24, 2023

By Thomas M. Lynberg

WIDCO is a surface coal mine located near Centralia, Washington. The WIDCO preparation plant processes over 7 million tons of run- of-mine coal each year with a product yield averaging 72%. In the jig type preparation plant the fine refuse amounts to approximately 130 dry tons per hour of 28mesh by 0. This fine refuse material is thickened in a 160ft. diameter static thickener with the use of lime as a coagulant and organic polymer as a flocculant. Once thickened the fine refuse, which is predominately bentonitic clays, has been dewatered and disposed of using several different methods. These methods will be discussed and include vacuum disc filters, ponds, solid bowl centrifuges, belt filter presses and experiments with electrokinetic dewatering.

Jan 1, 1981

By P. Hickey

"The object of this paper is to describe how the Iron Ore Company of Canada develops its management personnel. It will elaborate on the practical application of Supervisory Training and Management Development.Why are Supervisory Training and Management Development important? The answer has been the subject of many textbooks. Dr. Ken Blanchard, author and consultant, addressed this issue concisely when he said that effective managers and organizations must do two things, ""get results and develop people"". lPeople development at IOC is best illustrated through its supervisory training and management development programs. For the past twenty-five years IOC has been recognized as an industry leader in the training field. Periodic studies have played their role in establishing and maintaining this distinction. For example, in 1974, the company decided to review and up-date all its training programs. At this time, it established its own Task Force on Training and this resulted in the development of many of our present programs. Today, Supervisory Training (i.e. for first and second level management) at the Carol Project in the Labrador City area consists of various programs including: New Foreman Induction, Foreman Entrance School, Basic Management Skills, Management II, and Effective Presentations."

Jan 1, 1983

By L. L. Anderson

Western bituminous coal can be processed to low sulfur liquid fuels by fast reactions. A process (LEFCO) under development at the University of Utah uses coal and catalyst under hydrogen pressure to convert 60 to 70 percent of the coal matter to fuel liquids and gases. Coals have been processed in small diameter (less than 1/2 inch) tubes and at reaction residence times of less than 10 seconds. Effects of process variables on the yield and quality of products have been studied. General features of the process and the properties and characteristics of the products produced are presented. Special features of the process that distinguish it from other liquefaction processes under development are also discussed.

Jan 1, 1975

By A. Ersoy, M. D. Waller

The principal factors which require consideration in predicting drilling rates are the bit-type, the bit operating parameters and the characteristics of the penetrated rock. A single index is not a sufficient basis for predicting performance. A variety of rock types were drilled in the laboratory with polycrystalline diamond compact (PDC) and impregnated diamond core bits using a fully instrumented drilling rig at different rotational speeds and with a range of weights on the bit. Quantitative determinations of a wide range of textural, mechanical and intact rock properties were also made. Multi-variable linear regression analysis was then used to develop predictive models of rates of penetration from the operating and rock property data. The models have been verified by statistical tests. The analysis indicated that the models for the pin and hybrid PDC bits have potential for practical application. However, although the model for the impregnated diamond bit appears to be reasonable from a purely statistical point of view, it may not be satisfactory for drilling uses as it is based on two measures of rock hardness alone. The application of multiple regression analysis to PDC drilling performance is novel and the technique shows promise for the prediction of rock drillability with PDC bits. The ability of the technique to provide a mathematical characterisation of the performance of new drill bits in specific rocks may prove to be of value to drill manufacturers and users

Aug 1, 1995

By André Luis Martins de Souza

O objetivo do estudo foi medir e aumentar a produtividade das equipes de manutenção - em uma mineradora multinacional - dentro e fora das paradas de manutenção, avaliando os principais fatores que influenciam o indicador e, ainda, reduzir os custos de manutenção referente a contratação de efetivo terceirizado através da inovadora metodologia Six Sigma, para este trabalho utilizou-se um metodo quantitativo, analítico e experimental. Após a finalização do projeto obteve-se o aumento da produtividade da equipe de manutenção em todos os turnos analisados e os custos foram reduzidos em aproximadamente R$ 200.000,00 e o tempo para resolver pendências que era de 50,1 dias foi reduzido para 18,1 dias.

Oct 30, 2017

Jan 1, 1920

By F. H. Deist, M. P. Roberts

"The Collieries Research Laboratory of the Chamber of Mines of South Africa is developing a coherent system of programs to aid in the full spectrum of activities arising in the planning of new as well as operating mining enterprises. It is the purpose of this paper to describe the design and application of two subsystems in the complex.One of these subsystems is an initial version of a production simulator. This program draws upon a model of a mining enterprise and simulates the operational and financial aspects of a set of alternative mine production plans.These plans are specified in terms of proposed sequences of operations. Details such as reserves, production rates, resource requirements and so on, are taken from the model.Physically, the model takes the form of a cross-referenced data base, maintained by means of a general file maintenance system which is another subsystem described.The paper concludes with a description and analysis of the first practical application of the two programs."

Jan 1, 2014

Considerable attention has been given to the restoration of low-level radioactive (<1000 pCl/g) sites contaminated during the early years of the atomic energy program. Current clean-up activities which involve the relocation of contaminated soils to licensed disposal sites have been shown to be very costly due to the large volumes of soils which must be excavated, transported and stored. Recent characterization studies conducted at Virginia Tech suggest that the volume of soil requiring disposal can be greatly reduced using mineral processing techniques such as classification, density separation and froth flotation. This article discusses the application of these technologies for soil remediation and describes a conceptual flowsheet for treating soil samples from two contaminated sites.

Jan 1, 1997