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By Jurgens J. Louw, Vincent C. Smith, Gareth C. Smith, Agit Singh, Dave G. Hulbert

"During 2000 Mintek Developed the PlantStar plant wide control platform for the minerals processing industry. The flexibility of the PlantStar control platform has enabled Mintek to investigate and easily develop new control strategies for both milling and flotation. This includes a Solids Feed Controller, a Safety Limit Controller, Mill Power Optimiser and Flotation Optimiser, amongst others.Processes with long dead times, like a feed belt to a mill, are difficult to control. The solids feed controller was developed for minerals processing plants using a specialised time delay compensator. Using conventional time delay compensators that are purely model based, results in robustness problems due to model uncertainties. The Mintek Solid Feeds Controller makes use of a plant model, but compensates for model inaccuracies, giving more controller stability and a more robust delay compensation algorithm.Often there are more variables on a plant that need to be controlled (process variables) than there are variables to control them with (manipulated variables). Process constraints are often reached and violated. Safety control loops are necessary to prevent constraints being reached. The safety limit controller has been developed to switch smoothly between normal and safety control loops without bumping the process. The safety loop output is chosen in accordance with a predefined list of priorities and whether the respective constraint boundaries are exceeded.The Mill Power Optimiser helps to find the power peak on the mill power curve. It continuously perturb the solids feed rate to learn ‘where’ on the curve the mill ‘was’ and then to drive it continuously toward the middle, maximum power drawn. This insures maximum grind with maximum throughput. It also prevents power dips due to mill overloads by cutting the solids feed to a minimum if the power drop below a specified threshold. Once the power rises above the threshold the solids feed is increased again to an intermediate value from where it start the perturbations again to find the maximum. This makes the milling circuit easier to operate."

Jan 1, 2003

By J. B. Rubinstein

"The paper gives an overview of the history of flotation machine development. The laws of their evolution are stated and the place and role of column flotation are demonstrated.The major parameters of column cell diameter and height are discussed. Options are proposed for optimization of the hydrodynamic characteristics of large-capacity column cells. The high efficiency of columns with cell height of 4-6 m is demonstrated. The optimum parameters of multisectional column machines are determined. Their advantages compared to monocells are shown. A scaling-up procedure for column machines was developed based on flotation macro- and microhydrodynamics simulation."

Jan 1, 2003

By R. Daignault et G. O. Allard

The Chibougamau area represents a part of the Abitibi greenstone belt. The rocks constitute a volcanic pile (Roy Group) overlain by a volcano-detritic sequence (Opemisca Group). Three important periods of tectonic deformation have been distinguished. The first one produced folds with north-south horizontal axes. The second one is responsible for the isoclinal east-west folds, and the associated regional schistosity. Reverse faulting contemporaneous with this period of deformation, produced two distincts effects. In some cases the faults cause a repetition of the stratigraphic sequence. Whereas in others the faults truncate second period folds. Domes and basins interference pattern are produced by the superposed effect of Di and D2 deformations. The motion of these two periods would be more or less contemporaneous. The deformation could be generated by rising diapirs of early plutons combined with the progressive formation of troughs by gravitational subsidence of denser strata. The rising diapirs of late granitoid plutons produces a wraparound of the host strata.

Jan 1, 1984

Major activities of the Bureau of Mines Explosives Research Center during fiscal year 1966 (July 1, 1965 to June 30, 1966) are reviewed briefly. Part 1 summarizes significant accomplishments of the projects that were active during the report period. Part 2 presents short abstracts of the publications that appeared in the Bureau series and in other media during fiscal year 1966. Publications issued after June 30, 1966, are noted where pertinent in foot- notes but are not abstracted. ACKNOWLEDGMENTS The Bureau of Mines gratefully acknowledges the support given through cooperative agreements by the following organizations to investigations conducted by the Explosives Research Center during fiscal year 1966: Manufacturing Chemists' Association. The Sulphur Institute.

Jan 1, 1967

By M. Pötsch, W. Schubert, A. Goricki

Geological and geotechnical data are essential for the design of tunnels. To determine the rock mass behavior and the support of a planned tunnel excavation a consistent method for rock mass characterization and excavation and support determination has been developed. Probabilistic data processing with analytical methods is used for the quantification of the procedure and allows an evaluation of the applicability and the technical risk of different excavation and support methods. The sensitivity of the procedure on selected input parameters is highlighted in a parametric study. Finally an application of the procedure illustrates the use of the described method of probabilistic excavation and support determination for tunnels. Des données géologiques et géotechniques sont décisives pour la planification d’un tunnel. Pour la détermination du comportement des strates, le choix du soutènement et de la méthode de progression une description compréhensible de la montagne a été développée. À l'aide d'un traitement de données probabiliste, la procédure proposée est transposée quantitative sur une base de méthodes analytiques. De cette manière l'évaluation des méthodes de construction et la détermination du risque technique deviennent possibles. La sensitivité de la procédure de différents paramètres d'entrée est représentée dans une étude de paramètre. Pour finir, l'application de la procédure décrite est montrée à l’aide d'un cas pratique. Geologische und geotechnische Daten sind entscheidend für die Planung von Tunnels. Für die Ermittlung des Gebirgsverhaltens und der Festlegung von Ausbruch und Stützung wurde ein nachvollziehbarer Ablauf der Gebirgsbeschreibung entwickelt. Mit Hilfe von probabilistischer Datenverarbeitung auf Grundlage analytischer Methoden wird die vorgeschlagene Prozedur quantiativ umgesetzt. Dadurch werden die Bewertung von Baumethoden und die Ermittlung des technischen Risikos ermöglicht. Die Sensitivität des Verfahrens von einzelnen Eingangsparametern wird in einer Parameterstudie dargestellt. Abschließend wird anhand eines Beispiels die Anwendung des beschriebenen Verfahrens gezeigt.

Jan 1, 2003

Several common ratios used for determining spontaneous combustion activity rely on comparing the amount of various products of oxidation with the amount of oxygen consumed to produce these products. As coal gets hotter, oxidation reactions become more efficient meaning more products produced for less oxygen consumed. There are many problems associated with accurately determining the true amount of oxygen used. These problems relate to the monitoring technique (and its associated uncertainties) used to generate the results, deficiencies in the established equations utilized in calculations, dilution with other gases and other sources of oxygen depletion. Typically the oxygen deficiency is over estimated, resulting in the under estimation of the indicating ratio. For this reason the use of ?one off? calculations to determine the status of the underground environment is not recommended. Instead trends of these ratios should be used to identify increases which indicate an increase in oxidation intensity. This paper outlines problems associated with the monitoring techniques and equations used to determine the oxygen deficiency.

Jan 1, 2009

By Steve Wiig

In 1987, the Rock Springs, WY district office of the US Bureau of Land Management (BLM) began to develop an automated system to store, maintain and manipulate more than 14,000 drill hole logs contained in the district's office files for various solid leasable minerals. The development of this system was based predominantly on a trial-and-error basis, with many procedural changes incorporated over time. The current Automated Drill Hole Database and Analysis System will continue to evolve with new software developments and increased personal expertise in this field. The mission of the BLM's Branch of Solid Minerals is mandated by a series of federal laws. The most important are The Mineral Leasing Act, the Federal Land Policy and Management Act, the Federal Coal Lease Amendments Act and the Surface Mining Control and Reclamation Act. Several regulations, promulgated from these laws, dictate that BLM must perform certain tasks and functions as part of its specific duties. The regulations that apply to the BLM Solid Minerals program are codified at 43 Code of Federal Regulations (CFR) 3400 for coal, and at 43 CFR 3500 for non-energy solid leasable minerals, such as sodium, phosphate and potash. Specific functions required of the Branch of Solid Minerals necessitates the use of geologic and drill hole data analyses. These functions can be divided into pre-lease and post-lease. Examples of pre-lease functions that normally require some level of drill hole data analyses include:

Jan 1, 1992

By Kwang-Tae Kim, Yong-Kun Choi, Jeong-Soo Chong, Yun-Jae Lee

An annex building at the former Agency for National Security Planning(NSP) complex located in downtown Seoul was demolished by progressive collapse method. This work was done as a part of efforts to restore the landscape of Namsan Mountain which lies in the Center of Seoul. The five-story reinforced concrete structure was razed in 5.5 seconds by the 29kg of high powered explosives which were placed in some 320 holes in the building with floor area of 2,577 m². The asbetos and all the other finishing materials in the building were removed before the demolition and the specially coated wrap minimized the spread of blasting dust. Seismic and air overpressure waves were monitored at 8 points, which were below safety limits and the continuous communication with neighborhood prevented any complaint.

Jan 1, 1998

By Shaw Bill

The paper describes of the JORC Code in terms its background working environment and reasons for success, and provides references to papers which cover the subject in more detail. It then discusses the two major developments in Australasian reporting standards in the last two years: the revision of the 1999 Code, and the introduction in early 2003 of the “ROPO” (Recognised Overseas Professional Organisation) initiative. The purpose of the JORC Code is to provide a minimum standard for reporting of Exploration Results, Mineral Resources and Ore Reserves in Australasia, and to ensure that public reports on these matters contain all the information which investors and their advisers would reasonably require for the purpose of making a balanced judgement regarding the results and estimates being reported.

Apr 22, 2003

By V. I. Zhuchkov, L. A. Smirnov, E. I. Arzamastsev, A. A. Babenko

A brief analysis is given for state-of-the-art of manganese and chromium ferroalloy production in Russia and their consumption by metallurgy plants. The main causes of low output of manganese and chromium ferroalloys, and ways to resolve the issue of ferroalloy production development are considered.

Jan 1, 2004

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson, W. Hasz

Technology to enhance safety during mine hoisting has been developed by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Assessment of current hoisting technology suggests that monitoring conveyance position and load directly from the skip or cage top offers several significant safety advantages. Wireless data transmission schemes and a package consisting of sensors, batteries, and a charger mounted on the wire rope and skip have been developed. A state-of-the-art automated hoisting test facility was constructed to test the concept in a controlled laboratory setting. Field tests in a fill-size shaft are underway.

By R. E. Brewwe

"INTRODUCTION Anyone who has had frequent occasion to compare methods of analysis and testing as employed in European countries with those used in the United States has felt the need of a table or graph giving the relationship between the units of measurement of finely powdered materials. Most of the few published comparisons include only two series of sieves and often require tedious interpolations to adapt the data of one series to the series more familiar to the reader. To eliminate such deficiencies, the author hopes that the discussion and comparison of fine-series sieve sizes presented here will conserve the time of interested research workers.ACKNOWLEDGMENTSThe author is deeply indebted to Virginia B. Strathearn, scientific aide, for help in compiling the information from the literature and to W. A. Solvig, senior chemist, for valuable suggestions in preparing the manuscript.SQUARE-MESH-SIEVE SERIES OF DIFFERENT COUNTRIESSieving analyses of powdered materials have been placed on a comparable basis in different countries by the introduction and adoption of standard sieve-scale series. Series of wire-cloth square-mesh sieves in common I oratory and industrial use include: Institution of Mining and Metallurgy standard laboratory screens (I.M.M.); British Standards Institution standard for fine-mesh test sieves (B.S. or B.S.I.); Tyler standard sereer-scale sieves; United States standard sieve series; Deutsche Industrial-Nermen (DIN); and the standard control sieves of the Association Francaise de Normalisation (AFNOR). With the exception of the I.M.M. series in which the opening is equal to the diameter of the wire, the general proportions of the various series of sieves are similar. The size of British and American sieves is designated by the number of meshes or openings per linear inch or, more recently, by the number of microns per linear sieve opening. In a technical sense the word ""mesh"" is meaningless, unless the diameter of the wire is also given, so that the size of the opening can be determined. On the Continent sieves are designated either by the nunber of Mesh per linear centimeter or by the number of openings per square centimeter."

Jul 1, 1944

By A. Dogan Paktunc

Abstract - The Mechanic Settlement pluton is a small body of mafic and ultramafic rocks of tholeiitic affinity, occurring in the Late Neoproterozoic volcanosedimentary rocks of the Avalon terrane of the Appalachian Orogen. The lenticular-shaped intrusion is layered and consists of ultramafic and mafic lithologies in at least six cyclic units that are relatively thin or short-lived. The lowermost exposed portion of the intrusion is characterized by the cumulate sequences of olivine and olivineclinopyroxene and display relatively flat rare earth element profiles. In the overlying lithologies, plagioclase is the dominant cumulus phase following olivine in the crystallization sequence. Olivine ranges in composition from Fo73 to Fo85 and plagioclase from An62 to An89. Variations in the compositions of orthopyroxene and clinopyroxene are within Wo0-4En52-87Fs11-45 and Wo39-50En23-50Fs3-19. These mineral compositional variations in part reflect cryptic patterns and correspond to normal fractionation trends in cyclic units. Elevated Pt and Pd concentrations of up to 2.6 ppm occur in ten zones within the central cyclic series in association with both the peridotitic and gabbronoritic rock types. The mineralized zones are about several meters thick and appear to have lateral continuities over several hundred meters, suggesting that they are stratiform. Platinum-group elements (PGE) occur as discrete platinum-group minerals (PGM) including vysotskite, merenskyite, michenerite, sperrylite, stillwaterite, and hollingworthite that are associated with magmatic sulfides composed of pentlandite, pyrrhotite, and chalcopyrite. PGM grains range in size from a few micrometers to well above 20 µm. Sulfur isotope ratios and the Se/S ratios of the mineralized rocks are typically higher than the mantle values. Sulfide saturation probably occurred as a result of assimilation of crustal rocks and magma mixing during emplacement of subsequent pulses of magma. Repetition of the PGE mineralization in rather thin cyclic units suggests that the replenishing magma probably had high PGE levels and was saturated with respect to sulfide during emplacement. Ingression of the replenishing magma into the chamber in a turbulent plume and its mixing with the resident magma was probably responsible for the formation of the PGE mineralizations in the Mechanic Settlement pluton.

Jan 1, 2000

By S. Matsuyama, S. Tomita, H. Kawahara, G. Deguchi

A proper management system of coal mine methane gas associated with underground mining activities is essential for the mine safety due to its nature of explosion. Optimum design of the mine ventilation and gas drainage need accurate prediction of gas flow rate emitted by mining activities. Permeability to gas, which is affected by stress conditions of surrounding rock mass, governs the emission rate of the gases. JCOAL has developed a three dimensional FEM simulation program named Mine Gas Flow 3D (MGF-3D). MGF-3D is designed to predict the volume of methane gas emitted from surrounding coal and rock seams based on stress distribution and permeability change which are determined by 3D stress analysis. In MGF-3D, stress change and/or expansion of fractured zone affected by mining is calculated at the first and then gas emission into roadways and longwall panels under the determined stress conditions is calculated using Darcy’s law. MGF-3D also can set up a number of pre-drainage holes and estimate drainage gas volume from each hole. This function makes MGF-3D remarkable program. These simulations for gas emission can contribute to mine gas utilization plan. Comparison between actual measurement of gas emission in the underground mine and simulation results has been performed and availability for the mine safety and problems with MGF-3D are discussed in this report.

Jan 1, 2003

By Carlos Guillen Morales

Como parte del proyecto de estudio de impacto ambiental presentado por la Compañía Minera Antamina (Ancash), el presente trabajo describe la reutilización de las aguas residuales de los procesos mineros realizado en Huarmey. El estudio plantea el transporte el concentrado de mineral desde la mina hasta el puerto de embarque en Huarmey a través de camiones utilizando una carretera que facilitaría el desplazamiento de los mismos. Una vez llegado el concentrado al puerto de embarque, se separaría el agua del concentrado y el agua sería tratada para luego descargarla en el mar. Sin embargo, por análisis posteriores, se optó por otra propuesta más ecológica, donde se traslade los concentrados de cobre y zinc en suspensión acuosa a través de un minero ducto, y el agua tratada remanente del transporte de mineral, sería disipada mediante una plantación forestal, evitando la descarga al mar, generando empleo y una extensa área verde en el desierto de Huarmey. De forma que se innova en la minería a través de la reutilización de las aguas y se desafia las condiciones extremas del desierto costero para desarrollar una superficie vegetal que consumiera esta agua.

Sep 12, 2005

By Marlyn King, Kevin Peterson

Power Decks are voids created in the bottom of the borehole through the use of a suspended Super Plug. Explosive energy is started downward at initiation creating high pressures which find relief at the comers of the borehole cylinder in the bottom of the hole. This relief creates a horizontal break to the neighboring boreholes - the same effect as presplitting. This “presplit” represents a change of mass to.the explosive energy,and it is reflected upward in the more efficient form of tensile waves. This provides better use of the explosive energy than compression waves. This technique has created a new way of looking at the ways that explosive energy is transported through the rock mass.

Jan 1, 2002

By P. Massi

"Wholly owned by the Coniagas Mining Company, the oldest continuously listed mining company on the Toronto Stock Exchange, St. Andrew Goldfields is located on Hwy. 101 approximately 30 miles east of downtown Timmins, Ontario. Geographically situated on the Porcupine-Destor Fault, the mine and mill in Stock township is positioned in the heart of Northeastern Ontario's goldmining communities.In July 1988, a 600 ft. shaft, hoist, and compressors were already in place when construction started on a 500 T.P.D. capacity C.I.P. mill and crushing plant.By June 15, 1989 the mill was commissioned and attained the design capacity by August of that same year. Since then, changes to the circuit have increased throughput to 900 T.P.D. from two significantly different ore sources.Meeting the Ministry of the Environment's guidelines is an ongoing commitment utilizing the Inca S02 process in line between the tailings pond and secondary polishing pond.INTRODUCTIONExploration on what is now known as St Andrew Goldfields' Stock Township Mine was carried out ln the early l960 1 s by Hollinger Mines Ltd. The property was acquired by Quebec Sturgeon River Mines 1n 1973 and the main shaft was started ill 1979.When St Andrew Goldfields was incorporated 1n 1983, exploration and development commenced to identify the ore body. The company decided 1n 1987 to bring the Stock township property into production after an extensive feasibility study and testwork at Lakefield Research in Toronto. Leslie Engineering was contracted to design, engineer and procure al 1. equipment from the coarse ore bin to the tailings distribution system and backfill plant"

Jan 1, 1992

By R. J. Forzatti

The production of sulphuric acid from sulphur generates heat. The majority of this heat is recovered as steam and is often used to generate electricity. Heat not recovered as steam is rejected to cooling water systems. The design of the turbine, condenser, and cooling water systems impacts the overall water, energy, and environmental footprint of the plant. This review considers a conceptual 2000 t/d sulphuric acid plant with several alternative cooling water systems. The review utilizes Hatch?s 4 Quadrant sustainable design tool to compare the alternatives on both an economic and a weighted sustainability scale.

Jan 1, 2014

By Sun Chuanyao, Jia Muxin

Generally, if the bond valence (BV) between metal ion and oxygen of the mineral is greater than 0.8, only surface species –Me-O-H or –Me-O exposures on the mineral interface, if the BV is between 0.2-0.8, the metal ion exposures on the interface, and if the BV is less than 0.2 the metal ion dissolves into water. The PZCs of oxide minerals and island silicate minerals are determined by the bond valence of the bond in the mineral crystals, the higher the bond valence the lower the PZC of the mineral. So the PZC sequence of Al2SiO5 minerals is kyanite> andalusite> sillimanite. The general rule for framework silicate minerals is as: The higher the Al content, the lower the PZC of the mineral, when the ratio of Al to Si in the tetrahedron skeleton is below 1:3. The higher the Al content, the higher the PZC of the mineral, when the ratio of Al to Si in the skeleton is between 1:3 and 1:1. The general rule for layer silicate minerals is summarized as: the three-layer silicate minerals have much lower PZCs than that of the two-layer silicate minerals. The threelayer silicate mineral with the octahedron layer occupied by lower charged cations has lower PZC than that of the three-layer silicate mineral with the octahedron layer occupied by higher charged cations. The twolayer silicate mineral with the octahedron layer occupied by lower charged cations has higher PZC than that of the two-layer silicate mineral with the octahedron layer occupied by higher charged cations. The layer silicate mineral with Al substitution in the tetrahedron layer has lower PZC than that of the layer silicate mineral without Al substitution in the tetrahedron layer. Such pyroxene minerals whose M1 is occupied by a trivalence cation and the M2 is occupied by a monovalence cation has lower PZCs than those both M1 and M2 are all occupied by bivalence cations. Such hornblende minerals whose M2 is occupied by a trivalence cation and the M4 is occupied by a monovalence cation has lower PZCs than those both M2 and M4 are all occupied by bivalence cations. There is no Si4+ or 4 coordinated Al3+ exposures on the surface of framework silicate minerals, the metal ions of three layer or chain silicate minerals are compact between tetrahedron layersor chains, they hinder the metal ions to interact with oleate acid radical, the metal ion octahedron layer exposures on the surface of a two layer silicate mineral, but the the oleate acid radical can not attach to a metal ion by replacing a –OH- that connects three metal cations in the same time, So the floatability of such silicate mineral is bad. The metal octahedron chain style of an island silicate mineral affects it floatability, the mineral exposures octahedron chain metals with two dangling bonds in two directions floats better than the mineral exposures octahedron chain metals with two dangling bonds in one direction.

Jan 1, 2003

By D. R. Dolinar

The fall of small pieces of rock between roof bolts causes over 80 pct of the ground fall injuries in underground coal mines. Roof screen, if installed on the bolting cycle, can significantly reduce the number of these injuries. As the surface of the roof fails, the screen will have to retain the broken rock without failing or excessive deformation. Welded wire screen is the most common type of screen material used for roof surface control in underground coal mines. The load-deformation characteristics and the load capacity of welded wire screen were evaluated in the laboratory in a specially built test frame. In the frame, the square screen sections were held in place by bolts and bearing plates at the four corners while a center load was applied to the screen. The parameters evaluated included the wire gauge and configuration, the bearing plate loads and bolt spacing. The wire gauge of the tested screen was 4, 6, 8, 9 and 10. Maximum screen capacities for both load and displacement were developed for each of the wire gauge sizes along with the screen stiffness. This information can be used for screen selection and for the evaluation and determination of screen performance. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009