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By Qiong Wu, Li Guo, Qinghua Gu

BP neural network is a multilayer feedforward network trained by error back-propagation algorithm, which is one of the most widely used neural network models. However, BP neural network has exposed more and more shortcomings and deficiencies with the expansion of the application scope. In the prediction of ore quantity, BP neural network has the characteristics of slow convergence and easy to fall into local minimum point. In order to obtain the global optimal solution, and to improve the defects of BP neural network, this paper proposes combination optimization algorithm of genetic algorithm (GA) and BP neural network to improve the speed and accuracy of forecasting the main design flow chart and the analysis of the sort distinguish algorithm are offered, and then some problem in the design and debugging of the algorithm are discussed. On this basis, the GA-BP neural network model is constructed and applied to optimize the initial weights and threshold value of BP neural network. This model choices the floating point coding method to encode the connection weights and thresholds, and divides subjects into several populations. Through the introduction of selection, mutation, crossover, initial weight and other operators, making operational synergies between the various groups. This study selects 30 geological units, 8 quantitative variables (Pb, Zn, Cu, Mo, Si, Ni, Co, V) and 12 qualitative variables to carry out empirical analysis. Then the simulation of the algorithm is carried out in MATLAB and the parameters are analysed. By normalizing the input samples, 22 groups of observation data are used as the training data for prediction, and the latter 8 groups of observation data are used as the test data to be verified. The results show that when the ore quantity characteristics are not very significant, the model will produce prediction bias. But the improvement of the algorithm increases the efficiency of the function approach capacity of BP neural network and conquer the BP neural network system’s instability. It provides an auxiliary guide for ore prediction, which have higher reference value.

Jan 1, 2017

By S. Swanepoel, A. V. Cherkaev, Q. G. Reynolds, M. Erwee

Ferrochrome (FeCr) is a vital ingredient in stainless steel production and is commonly produced by smelting chromite ores in submerged arc furnaces. Silicon (Si) is a componrnt of the FeCr alloy from the smelting process. Being both a contaminant and an indicator of the state of the process, its content needs to be kept within a narrow range. The complex chemistry of the smelting process and interactions between various factors make Si prediction by fundamental models infeasible. A data-driven approach offers an alternative by formulating the model based on historical data. This paper presents a systematic development of a data-driven model for predicting Si content. The model includes dimensionality reduction, regularized linear regression, and a boosting method to reduce the variability of the linear model residuals. It shows a good performance on testing data (R2 = 0.63). The most significant predictors, as determined by linear model analysis and permutation testing, are previous Si content, carbon and titanium in the alloy, calcium oxide in the slag, resistance between electrodes, and electrode slips. Further analysis using thermodynamic data and models, links these predictors to electrode control and slag chemistry. This analysis lays the foundation for implementing Si content control on a ferrochrome smelter.

Mar 14, 2024

By R. H. Zeng

Many subsidence researchers in the U. S. have developed new empirical function methods to predict subsidence, or attempted to validate some empirical functions developed by foreign researchers for use in the U. S. An attempt is made in this paper to develop a new empirical function to predict a surface subsidence basin due to longwall mining. In the U. S., the emphasis of empirical methods for the subsidence prediction over longwall panels has been in large part on determining the profile functions for the major cross-sections of a subsidence basin. In this approach, the surface monuments are usually laid out along the major cross-sections and thus, the subsidence profiles developed are restricted for subsidence prediction along the major cross-sections. However in practice many monuments or surface structures for which subsidence prediction for damage evaluation is required, are not laid out along the major cross-section of the basin. In such cases, it is difficult to get either the empirical profile function for the cross-sections where these structures are located or to predict their subsidence based on the profile function developed for the major cross-sections. Therefore, there exists a strong need to develop a subsidence basin function with a reasonable degree of accuracy, which can be determined or confirmed by the data of scattered monuments on a surface basin. The same subsidence basin function can also be used for prediction of subsidence for any arbitrary points over a longwall panel. In 1982, He (1) proposed the clastic theory, for which he developed the basic differential equations describing the movement and deformation of overburden due to underground mining, and performed the selection of best solution for the equations. He found that the Weibull dietribution is the optimal solution. The Weibull distribution has three parameters that vary to fit the subsidence profile so well that the profile function derived from it provides a high degree of accuracy in subeidence prediction. However the results

Jan 1, 1986

By Mao Bai

In predicting the integrity of under-mined structures, surface horizontal displacements and curvatures are frequently of greater importance than the more homogeneous vertical displacements. Accurate evaluation of mining induced subsidence and horizontal displacement further requires that the predictive model adequately represents the subsurface geology, mining geometry and extraction sequencing. The following documents an extension of the Subsidence Prediction and System Identification method (SPASID) to the evaluation of horizontal strains. Comparisons are made between predictions from SPASID and two other empirical methods against measured data from a case study. The system identification method is illustrated to predict horizontal displacements and strains most consistently with the in situ data.

Jan 1, 1989

By Xiaodong Yu, Jinxia Zhang, Fusheng Niu, Hongmei Zhang

The three-dimensional (3D) fractal dimension is an important parameter to analyze the 3D structure and flocculation effect of the hematite flocs. In this work, the 3D fractal dimension of hematite flocs was predicted by establishing the particle swarm optimization (PSO) algorithm optimized with the back propagation (BP) neural network (PSO-BP). The proposed model considers four factors, namely, the flocculant quantity, flocculation time, stirring speed, and temperature, as the input parameters. We normalize the input data during the preprocessing stage. The BP neural network was optimized by using the PSO algorithm for realizing the 3D fractal dimension. The prediction accuracy and effectiveness of the model were evaluated. The experimental results showed that the predictions performed by the proposed PSO-BP neural network were better than that of BP neural network. In addition, the root mean square error (RMSE), mean squared relative error (MSRE), mean absolute error (MAE), and mean absolute relative error (MARE) of the proposed model are lower, compared with the errors of the BP network. Similarly, the measurement coefficient R2 of the proposed model is higher, compared with the BP network. The maximum absolute error of the model is 0.0772, the maximum relative error is 0.02405, and the regression coefficient r is 0.98592. These results showed that the proposed model has a good performance and high prediction accuracy. When verifying the practicability and the effectiveness of the proposed PSO-BP model, the prediction results of 10 groups of hematite flocculation experimental data under different conditions showed that the prediction value of the proposed PSO-BP model was closer to the ground truth as compared to the BP model. Therefore, the proposed model is suitable for predicting the 3D fractal dimension of hematite flocculation.

Oct 3, 2022

By M J. Nugus, F Clark, E J. Hill, J T. Carswell, J S. Cleverley, N H. S Oliver

High-nugget gold orebodies are difficult to model in 3D because samples from diamond drill core are generally too small to provide reliable estimates of the gold content of the larger body of rock, and therefore interpolation of gold assay values between drill holes is also unreliable. As a result, gold resources are generally underestimated in areas of high nugget. In practice, proxies for gold mineralisation, such as presence of alteration, specific structures or high vein density, have been used by geologists to predict rocks which are favourable for mineralisation. However, there has been no automated method for combining the predictive capabilities of several proxies, except by human judgement.We have been developing a method to combine several different types of geological features or geochemical analyses into a single measure using conditional probability. Conditional probability provides a meaningful numerical measure for the favourability of rocks for containing high-grade gold mineralisation. This measure can be interpolated in the exploration space, providing a sound basis for a 3D model of the orebody. We have developed this technique using data from the Sunrise Dam Gold Mine, which is a high-nugget orebody hosted in a structurally complex Archaean greenstone belt and which has historically proved to be a very challenging orebody to model.CITATION:Hill, E J, Nugus, M J, Clark, F, Oliver, N H S, Cleverley, J S and Carswell, J T, 2013. Predictive three-dimensional modelling of nuggety gold orebodies, Sunrise Dam, Western Australia, in Proceedings World Gold 2013 , pp 463-468 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Ruddle R. W.

Although copper has been smelted for many years, relatively small attempt has been made in the past to examine the fundamental physical chemistry of the processes involved. Therefore, technological developments apart, slow progress has been made with the development of improved or new principles of smelting. The methods at present in use in the majority of the world’s smelters are essentially those employed at the beginning of the present century; it is significant that many of the textbooks on copper smelting, written some 50 years ago, are still regarded as standard works. The book is divided into seven chapters. In the first the fundamentals of modern smelting processes are briefly outlined for easy understanding of the subsequent sections, while the next two chapters are confined to the more theoretical aspects of the constitution of mattes and slags. Some problems of considerable practical importance are discussed in the remaining four chapters; these are (1) magnetite formation, (2) copper losses during smelting, (3) the recovery of sulphur from the smokes produced during smelting, and (4) the elimination of impurities. A collection of thermodynamic data relevant to copper pyrometallurgy is presented in an appendix, and, for the convenience of readers not well acquainted with thermodynamics, a brief explanation of the thermodynamic terms and methods employed is given in a second appendix

Jan 1, 1953

The great additional clue given to professional books by adequate alphabetical and analytical indexes has been recognized from the beginning in the publication of the Transactions of the American Institute of Mining Engineers The bust ten volumes, edited by Dr Thomas M Drown, the secretary, were provided with indexes, as well as tables of contents Moreover, he included in Vol V (published in 1877), a consolidated index of Vols I to V , inclusive, and, at the triune of his resignation in 1884, he had prepared a similar index of Vols I to X , inclusive, which was published in the following year The indexes of the annual volumes from Vol XI on were made much more extensive than their predecessors Casual mentions, as well as important discussions, were included, the geographical localities of mines of works alluded to in the text were added in the index, and numerous cross-references were introduced, with the purpose of making it easy for the student to discover at once what the Transactions contained, either of thorough treatment or of hints and clues to further inquiry, concerning any topic, locality, or person within their scope In order to extend the advantages of this larger scheme to the earlier volumes a consolidated index of Vols I to XV , inclusive (published in 1888), was prepared by compiling the several annual indexes and introducing additional items for those preceding Vol XI Vol XX , issued in 1892, contained a similar consolidated index for Vols XVI to XX , inclusive, in 1897, a sepal ate index-volume, covering Vols XXI to XXV, inclusive, was published, and on 1902 appeared another for Vols XXVI to XXX These four indexes, for Vols I to XV, XVI to XX, XXI to XXV , and XXVI to XXX, respectively, bound together into a book of about 950 octavo pages have constituted for the last five year s a consolidated index to the Transactions which they cover-with the single difference that the book had to be consulted four times, where a single comprehensive index would require to be consulted but once This disadvantage, however, was relatively small, compared with the great convenience of finding by four trials m one book what would otherwise call for 30 separate searches in 30 books Moreover, the possession of the one might be most useful to a student who did not possess the 30, by indicating to him what they con-

Jan 1, 1907

THE second operation in the art of casting, and one of the greatest importance, is that of melting and thoroughly liquefying the materials of which you wish to make your casting. On this operation depends the whole outcome of your intentions and the perfection of your work. Without it, even though you had a great abundance of moulds and vast quantities of bronze, your desires, labor, and expense would all be in vain. In this operation I find on consideration that, in addition to experience, there are three necessities-perhaps indeed four-that must be provided without fail. The first is the furnace or other agent which contains the fire and the metal brought together. The second is the wood or charcoal which is the necessary and proper nutriment of the fire, from whose virtues are derived the greater or lesser forces which, according to their kind, are ready to effect what is required. The third is to have the materials disposed to easy fusion by means of corruption, alloying, or by their own nature. The fourth, as the motivating cause of the whole, could perhaps be listed as the first-this is the ingenuity and good judgment of the worker, together with the bodily exertions not only of himself but also of his helpers in addition. For, besides a certain ordinary caution, it is necessary to pay particular attention, first, to see that the furnaces, machines, ladles, hearths, refineries, and other kinds of instruments or similar vessels be made so as to dispose the metals for melting, and, when melted, that they easily maintain them so. These should also be prepared in such a way that they cannot be injured by the fire, for if they should be damaged the operation would fail. In order to do this, it is first necessary that you arrange the instruments with forethought and action so that the power of the fire can operate. Fire operates on things only when brought together with them in long-continued operation, or when driven by a great force of wind. It burns many things and softens others, but it makes the metals as liquid as water.

Jan 1, 1942

AS I told you before in the treatise on ores, once these are found (whether they are ores of metals or semiminerals) it is necessary to assay them in order to know what is in them, since the judgment of the sight is not sufficient for recognizing the quantity or even what substance they contain. For this reason, it is necessary to come to assaying and, with the knowledge of experience, to weigh their virtues and to proceed with the work or withdraw from it and its expense; and also through knowledge to make provision for their defects if some evilness harms the ores. For if you should have need of a thing that would help them and should not find it, all that you have done would be lost; and, on the other hand, if you should find that the ores are abundant and rich and easy to smelt, you take courage to continue without respect for anything. Therefore, in the following book I shall tell you first in general how the assay of all the metals should be made. I shall enlarge in particular on silver more than on any of the others since it is more important. Then I shall tell you how the ores should be prepared for smelting and also how blast furnaces and other furnaces for smelting such ores should be constructed, and finally how all elemental mixtures of metals are to be separated one from the other with the ability and power of art, and how they are reduced to their final perfection and fineness according to their species.

Jan 1, 1942

By David J. Kinneberg, Barbara E. Mangion, Arnold M. Savolainen

Analytical laboratories require a qualitative or semi-qualitative method of determining major and minor constituents in "unknown" samples to select optimal analytical techniques. This is exceedingly important in precious metal assay laboratories where the precision and accuracy requirements are exacting (routinely within 0.02%, absolute basis). This paper describes the use of an x-ray fluorescence spectrometer with a specially designed software package to select optimal analytical procedures and specify relevant analytical parameters. A wavelength dispersive XRF spectrometer is capable of quick and accurate analyses of properly prepared samples without extensive standardization. When coupled with a specially designed software package, this preliminary assay system is applicable to a wide variety of sample types including gold and silver bullion, karat gold and karat PGM alloys, high silver and high copper metallic samples as well as particulate samples of ores and sweeps. The system relieves the assayer of tedious calculations for silver inquartation and proofing, minimizes human error and standardizes selections over time. Most importantly, the system allows for independent verification of final assay results.

Jan 1, 1999

By Catherine T. Ziten

Introduction ?Environmental assessments required for permitting ?Focus on ammonia produced through mine construction & blasting ?Water quality guidelines: federal, provincial, IGO ?Reported values are typically estimates from other projects ?Predictive modelling of ammonia aimed to assist planning

May 1, 2009

By K. Morsi

The interest in spark plasma sintering has been growing considerable over the past few years. This has been brought about by the unique advantages of the process, which include reduced sintering temperatures and times and the production of materials with unique microstructures and properties. Despite its current reputation as an outstanding process that has solved major problems such as nano-powder consolidation, it has so far been largely limited to the manufacture of simple shapes, due to its inherent geometric configuration. In this paper we present preliminary results on spark plasma "extrusion" that can allow the production of extended geometries via electric-current processing. Preliminary results on the processing and microstructure of spark plasma extruded aluminum are discussed.

Jan 1, 2009

By Charles T. Ford

In 1971, Bituminous Coal Research, Inc~ established a program to provide the coal industry with the necessary information and technical capability to investigate and evaluate potential problems concerning trace elements in coal and coal-related materials. The initial efforts at BCR in developing or adapting analytical procedures for the precise determination of trace elements in the parts per million to parts per billion range were detailed in a report titled "The Development of Analytical Methods for Determining Trace Elements in Coal and Coal-related Products." A subsequent reports contained descriptions of reliable analytical methods refined by BCR for determining mercury in coal and coal ash and also in coal mine water. his paper reports initial progress in applying recently-acquired trace-element analytical capabilities to solving potential coal industry problems. In this case, the effect of a coal-cleaning process on the distribution and removal of potentially harmful trace elements in coal was evaluated. Coal cleaning offers the possibility of controlling potentially harmful emissions resulting from combustion of large tonnages of coal by removing the pollutants prior to combustion.

Jan 1, 1977

"Block caving is the preferred underground mining method to profitably extract massive, low-grade orebodies; however, lack of cave access inhibits understanding the rockmass response to mining, which is needed for safer, more productive operations. Combining large datasets from multiple sources with virtual reality scientific visualization (VRSV) is an alternative method for understanding complex cave behaviour, by providing virtual access to the cave. A customized VRSV module was developed at UNSW Australia to investigate rockmass response to undercut developments at a case-study block caving operation. Time/sequence effects are investigated in rockmass response to blasting, which is an important factor in hard-rock mines.RÉSUMÉ La méthode d’extraction souterraine par blocs foudroyés est la méthode préférentielle pour extraire rentablement des gisements massifs à faible teneur. Toutefois, le manque d’accès à la chambre restreint la compréhension de la réponse de la masse rocheuse à l’exploitation, ce qui est nécessaire pour obtenir des opérations plus sécuritaires et plus productives. La combinaison de grands ensembles de données de multiples sources avec la visualisation scientifique par réalité virtuelle (VRSV) constitue un autre moyen de comprendre le comportement complexe de la chambre en fournissant un accès virtuel à la chambre. Un module de VRSV sur mesure a été développé à l’Université de Nouvelles-Galles du Sud (UNSW) en Australie afin d’étudier, dans une étude de cas d’une exploitation par blocs foudroyés, la réponse de la masse rocheuse aux développements de galeries de sous-cavage. Les effets de temps/séquence sont étudiés dans la réponse de la masse rocheuse au sautage, ce qui est un facteur important dans les mines de roches dures."

Jan 1, 2016

By L. G. Austin

INTRODUCTION Autogenous (including semi-autogenous) grinding has probably been the most important single innovation in milling practice for the last twenty years. However, the design of these units has been largely a matter of trial-and-error, since the normal empirical laws for the design of ball mill circuits do not apply with exactitude to autogenous grinding circuits. There have been examples of autogenous mills failing to achieve output or product specifications. It is worthwhile, therefore, to attempt to develop a more detailed and precise set of design laws, using the concepts of specific rates of breakages and daughter fragment distributions (1), and performing mill simulations by computer. This type of approach has been applied to ball and rod milling (2, 3,4,5), but even for these mills it is by no means complete as yet (6), because of the amount of experimental work involved. There has not been a strong incentive for industry to develop new design procedures in ball and rod milling because the prior back-log of experience with these mills makes for easy design by empirical comparsion with existing systems. The new approach has been followed mainly by University groups (7,8,9,10), although experience in Australia (9,11) has shown the advantages of the approach. Stanley (12) has applied the approach to results from a large autogenous mill, and we will use many similar concepts to his work, but extend the concepts to a more

Jan 1, 1977

By D Cork, R Peet

"Methane is a signifi cant greenhouse gas. Methane is released from coal seams during the mining process, both in surface and underground operations. This uncontrolled release is termed æfugitive emissionsÆ and in underground mines is transferred to the atmosphere in ventilation air, known as ventilation air methane (VAM). The global VAM emissions are over 369 Mt of CO2-e/a (Butler, 2011; US EPA, 2010). Coal mines may abate this VAM or consider abatement should there be a price on carbon. These fugitive emissions are heading towards ten per cent of AustraliaÆs emissions by 2020 (Department of Climate Change, 2011).There are safety issues involved in VAM destruction. Due to the nature of coal, and coalextraction, unpredicted methane spikes above the lower-explosive-limit (LEL) can occur in theventilation air; for example outburst events or ventilation failure. This could lead to a mine fi re ifthe mine ventilation air was connected to a VAM abatement plant and the risks are left unmitigated.CorkyÆs is working with the mining industry to directly address these safety issues. CorkyÆs calltheir technology VAM RAB, which stands for ventilation air methane regenerative afterburner(VAM RAB). VAM RAB utilises the principles of a thermal oxidiser.This paper discusses fi ve independent layers of protection (ILPs) to fi rst stop methane reachingthe thermal oxidiser and secondly prevent the fl ame front from burning away from the VAMRAB. The test work completed or contemplated includes safety integrity level (SIL) assignmentto various vents, barriers and door systems to prevent a fl ammable mixture reaching the VAMRAB, proven rapid response methane monitoring sourced from the petrochemical industry, anddefl agration experiments to test the eff ectiveness of the passive geometry and active engineeringcontrols. These experiments and SIL assessments indicate that it is possible to safely connect theVAM RAB to a working coal mine.Further work is required to upscale the pilot safety work. Refi nement to the design is possible;for example improvement to safety duct controls once trialled at demonstration scale plus thermalenergy capture for power generation or other applications to provide heat. Nevertheless, thispaper shows how safety issues can be managed by a multilayer of protection approach usingvents, barriers and doors, and appropriate thermal oxidiser geometry."

Jun 1, 2012

By Jie Li, Zhongliang Tian, Xun Hu, Kai Zhang, Yanqing Lai, Hongliang Zhang

The Al-Sc Alloys show many advanced properties for a wide range of engineering applications. But the metal Sc must be added into the metal Al in the form of the Al-Sc master alloy, which is usually produced by the thermal reduction process. In this paper, the decomposition voltages of Sc2O3 and Al2O3 in Na3AlF6-K3AlF6-AlF3 melt were calculated based on the Nernst equation. And the Al-Sc master alloy was prepared in the melt at 950°C by electrolysis. The results show that the Al-Sc master alloy can be prepared by the co-deposition of Sc3+ and Al3+ at the cathode if the concentration ratio of Sc2O3 to Al2O3 in the melt is more than 2:1 under the condition of the aluminum electrolysis. SEM and ICP analysis of the product indicates that the Al-Sc master alloy is made of the phase Al and the phase Al3Sc.

Jan 1, 2016

By R. P. Smith

PRIOR to June, 1937, the employees of Hollinger Consolidated Gold Mines, Ltd., at Timmins, Ontario, received medical care for themselves under a contract system developed through an agreement between the employer, employee, and a contract physician. This form of practice is common to the mining industry in Ontario. But with the improvement in mining methods and conditions of living, and through an increasing demand for provision of a complete medical care, it was not any surprise when the employees of the Hollinger mine approached organized medicine and indicated their desire for a plan to provide their families with a more or less complete medical service in addition to that supplied for themselves. In April, 1937, this approach was made, and on June 18th, 1937, the Hollinger Employees' Medical Services Association was formed and started to provide medical services. A review of five years' experience is now presented. The Association provides complete medical service for the employee, his wife and family, as well as those dependents who are the total responsibility of the employee. The employee membership is limited to employees at the Hollinger mine in Timmins who reside in the immediate vicinity. The employee is examined by a Company doctor on application for employment and is subject to further examination by a specialise in chest diseases under the direction of the Workmen's Compensation Board of Ontario. The wife and family are not subject to examination but have to be registered when the employee is accepted for employment. The dependents, other than the immediate family, are subject to medical examination and approval after the employee has applied for such dependent or dependents to be admitted. Membership in the Association is obligatory when the employee is hired, but at the end of any Association year he may drop out if he so wishes.

Jan 1, 1943

By Guadalupe Sanchez, Roel Cruz, Sergio Castro, Claudia Beltrán, Isabel Lázaro

The recovery of zinc in refineries is strongly affected by the formation of zinc ferrites during the roasting of zinc concentrates. To achieve the highest zinc recovery most of these plants operate under high acidity and high temperature conditions in their leaching circuits. However, under these conditions high iron dissolution occurs. For iron control the common practice is to precipitate it as jarosite, and calcine is normally used as neutralizing agent. This practice causes a significant loss of metal values associated with the calcine, such as zinc ferrites and silver insoluble phases. These metal values are carried by the jarosite into confined waste in many plants. In order to diminish such losses, it is necessary to use a neutralizing agent that could substitute the use of calcine. An alternative neutralizing could be the basic zinc sulfate (BZnS). This work presents the results of a laboratory analysis on the required conditions for the BZnS production from process streams of a zinc refinery plant. Neutralizing behavior of BZnS was evaluated in iron precipitation as jarosite, in order to establish the feasibility of replacing the calcine and decrease the loss of zinc and other metals values during the iron removing step of the hydrometallurgical circuit of the zinc refinery under study.

Jan 1, 2014