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By L. Xiao

Using K-oleate as a collector and alizarin red S (ARS) as a modifying agent, selective depression of dolomite from francolite was achieved in alkaline medium (pH> 9.0). Interestingly. ARS was also found to depress igneous apatite in alkaline medium in oleate flotation of apatite and calcite. Adsorption of ARS alone on dolomite was found to be higher than that on francolite. Complimentary adsorption experiments of ARS and K-oleate showed that oleate adsorption was increased in the presence of ARS on francolite but not on dolomite. K-oleate adsorbs on both francolite and dolomite and causes precipitation of calcium and magnesium oleate. Such precipitates can be pre-vented when ARS is present. The results are explained in terms of competitive adsorption for the active sites on francolite and dolomite by oleate and ARS, and their interactions with dis-solved mineral species in solution.

Jan 1, 1988

By F. Patisson

During exothermic gas-solid reactions, heat generation makes temperature rise and modifies the rate of the various mass transfer processes, namely the chemical reaction itself, the pore diffusion and the external transfer. We have investigated this thermal effect during the oxidation of zinc sulfide porous pellets in a thermo balance furnace, between 550 and 900°C-and under O2-N2 atmosphere. The results have been' analyzed by using, firstly, the law of additive reaction times derived from the isothermal Grainy Pellet Model, and, secondly, a new numerical model taking into account non-isothermal conditions. Both the models can satisfactorily simulate conversion versus time, but the numerical model also depicts the temperature evolution within the pellet. Finally it is shown that owing to the heat generation the zinc sulfide oxidation takes place under diffusion control (3/4 internal, 114 external) in all the cases studied. During the course of reaction, the. pellet undergoes strong temperature variations, with thermal gradients confined to a shell oxide layer.

Jan 1, 1996

By Geoffrey S. Plumlee

The Summitville gold mine, located in southwestern Colorado, received tremendous publicity in the 1980's and 1990's for leaks of cyanide solutions from its heap leach facility. As is typical with cyanide spills, real time, geochemically rigorous assessments of the environmental effects were not performed. Past United States Geological Survey (USGS) research used simple mixing experiments to model the influx of alkaline cyanide heap leach solutions from Summitville into a nearby stream, whose waters were highly acidic due to severe acid-rock drainage (ARD) from the mine. These experiments indicated WAD cyanide rapidly degraded due to formation of Fe-Cu-CN solids and lesser HCN volatilization. The alkaline heap leach solutions also precipitated hydrous iron-and aluminum, oxides and hydroxysulfates (iron and aluminum 'supplied by the acid. rock drainage (ARD]), which then sorbed copper and other heavy metals from the ARD. These results indicate that mixing of cyanide heap leach solutions with ARD may be a cost-effective remedial method at mine sites where treatment of both is required. New experiments are currently in progress to further refine a potential remedial process.

Jan 1, 1998

By D Semini, B Newcombe

Base-metal sulfide refractory gold ores often contain a portion of ‘free’ gold that is amenable to recovery using gravity concentration methods, whilst the refractory portion of the gold is better recovered using flotation. The decision as to whether a plant treating a refractory gold ore should utilise gravity concentration or a flash flotation circuit (or a combination of both) within the grinding circuit is usually made at the design stage of flow sheet development. Very limited data is available in the published literature which provides an industrial scale comparison on which to base such a decision and conventional laboratory testing methods are often the only way of obtaining such data. The optimum processing route will also be mineralogy dependent.This paper presents the findings of operating a refractory gold plant with either flash flotation (normal operation) or a combination of flash and gravity recovery methods treating the cyclone underflow stream and will demonstrate the regions of the recovery profile that each contributes to. Size-by-assay analysis has been performed on a number of streams around the operating plant to gain an insight into the changes that occur when the gravity circuit is in operation in addition to the flash flotation circuit. A discussion around the implications to overall plant operation in combining the use of a batch process (gravity concentration) with a continuous process (flotation) is presented.CITATION:Newcombe, B and Semini, D, 2014. Interactions between flash flotation and gravity concentration – an industrial case study of a refractory gold concentrator, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 427–436 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

During induration of iron ore pellets produced from magnetite concentrates, there are many reactions occurring simultaneously. While the magnetite is being oxidised to hematite, carbonate fluxes are being calcined, leading to the formation of complex oxides. Calcination of fluxes and the formation of calcium and magnesium ferrites and silicates during the preheat stage can influence the magnetite oxidation process. As the calcination reaction proceeds quicker than oxidation at temperatures experienced during the preheat stage (700 - 1200¦C), the bulk flow of CO2 emanating from within the pellet should disrupt the diffusion of O2 to the magnetite reaction as the gas fluxes are similar in magnitude. This increases the time required for the oxidation of the pellet. Using an infrared rapid heating furnace, experiments were performed on heating individual magnetite green balls in an air atmosphere. These experiments showed that time played an important role in the extent of oxidation and calcination and temperature significantly influenced the initial evolution of high temperature phases such as magnesioferrite, calcium ferrites and calcium silicates. Understanding the kinetics of all these reactions for a particular pellet feed, and their interaction, is important for optimising the design of the induration furnace.

Jan 1, 2005

By Claude Bazin, Patricia Obiang

"The slurry density (pulp percentage of solids) and the size of the grinding media are often used for the optimization of an operating ball mill. In many cases a change of ball size is made at the slurry density used with the original ball size. But is the optimum slurry density changing with grinding media size? Laboratory grinding tests were conducted to answer that question and results indicate that more than likely there is no need to adjust mill slurry density when adjusting the size of a grinding media in a ball mill. Full scale behaviour could be different because slurry density affects the slurry transportation through the mill and the classifier operation.INTRODUCTIONOre preparation begins with a fragmentation step that liberates valuable minerals or exposes mineral surface to the environment. The size reduction step of a mineral processing operation is energy demanding and the optimisation of this process should always be an objective for the plant metallurgists. Various approaches could be considered for improving the operation of a grinding circuit. For a close grinding circuit an adequate tuning of the classifiers operation may lead to substantial savings (McIvor, 1988). Once a grinding mill is in operation, few variables remain to be considered for process optimization. The ball charge is usually maintained to achieve a target power drawn by the grinding mill motor. The rotation speed is seldom considered (McIvor, 1983; Bazin and Lavoie, 2000) as a change of mill speed usually implies a costly pinion change. If the liner and lifter configuration is critical for SAG and AG mills (Latchireddi et al., 2005), few discussions are available for ball mills (Fuerstenau and Abouzeid, 1985; McIvor, 1983). The mill feed size distribution can also be adjusted but this implies changing the upstream processes, which transposes the optimization process to another level. Modification to grinding media shape is a possible avenue (Cooper et al., 1994), but it remains that slurry density and grinding media size are probably the most frequently considered variables for the optimization of a ball mill."

Jan 1, 2007

By Liow Jong-Leng

A survey of the interactions of large gas bubbles formed from top and bottom injection of gases into melts was carried out. Spherical cap bubbles were found not to produce much splash when they break through the bath free surface except for that formed by plunging of the-spout at its edges. In contrast, the bursting of balloons produces cavities which give rise to liquid jets being ejected from the bath free surface. The position of the balloons relative to the bath free surface is an important parameter in the formation of the liquid jet. It is found that the interactions of multiple bubbles close to the free surface is important in determining the splash behaviour of gas injected systems.

Jan 1, 1996

By M. I. Kalashnikova, Y. M. Shneerson, M. V. Keskinova

Interaction between mattes having various compositions and solutions with a wide range of free acid and non-ferrous metals concentration have been studied in terms of chemistry, mechanism and kinetics. The solution acidity and oxidizers to reducers ratio in the matte-solution-gas phase system have been demonstrated to be the major factors determining the process behaviour. It was found that the types of copper and nickel secondary sulphides resulted from nonferrous metals precipitation from solution, depend on of the solution and initial matte composition. Based on these studies, technologies of matte leaching and nonferrous metal precipitation in the form of rich sulphide concentrates are developed.

Jan 1, 2004

By Ponisseril Somasundaran, H-L. Chen, University of Athens, D. R. Nagaraj, Zhonghua Pan, Jing Wang

Gums are often used as depressants for talceous gangue minerals in the flotation of nickel and platinum bearing ores. However, the mechanisms of gum adsorption on talc are not clearly established. In this work, adsorption of guar gum at the talc-solution interface is investigated using spectroscopic and allied techniques. Guar gum adsorption on talc is not affected significantly by changes in solution conditions such as pH and ionic strength. Electrokinetic studies showed that guar gum decreased the negative zeta potential of talc but did not reverse the charge. Fluorescence spectroscopy studies conducted to investigate the role of hydrophobic bonding using pyrene and dansyl probes showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, reduced the adsorption of guar on talc to the same extent as that for guar/alumina system, in which hydrogen bond plays an important role. All of the above results suggest that one of the main driving forces for guar adsorption on talc is hydrogen bonding rather than electrostatic or hydrophobic force.

Jan 1, 2003

By P. Somasundaran, G. Anastassakis, Z. Pan, D. R. Nagaraj

Gums are often used as depressants for talceous gangue minerals in the flotation of nickel and platinum bearing ores. However, the mechanisms of gum adsorption on talc are not clearly established. In this work, adsorption of guar gum at the talc-solution interface is investigated using spectroscopic and allied techniques. Guar gum adsorption on talc is not affected significantly by changes in solution conditions such as pH and ionic strength. Electrokinetic studies showed that guar gum decreased the negative zeta potential of talc but did not reverse the charge. Fluorescence spectroscopy studies conducted to investigate the role of hydrophobic bonding using pyrene and dansyl probes showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, reduced the adsorption of guar on talc to the same extent as that for guar/alumina system, in which hydrogen bond plays an important role. All of the above results suggest that one of the main driving forces for guar adsorption on talc is hydrogen bonding rather than electrostatic or hydrophobic force.

Jan 1, 2003

By Yuhsuke Mizukami

Crude high Cr containing steel such as tool steel, heat-resistant steel or stainless steel is produced by dissolution of high carbon ferro-chromium into molten crude steel. In the refining process, decarburization is performed at the first stage, and deoxidation is followed in the next stage. Therefore, the equilibrium relation between dissolved Cr and 0 in molten Fe-Cr alloy after decarburization is very important when yield of deoxidizer is considered for the ovemll control and optimization of the process. It is well known that the yield of deoxidizer does strongly depend on the kinds of refractories of furnace in the secondary refining process. In the present work, the equilibrium relation between dissolved Cr and O in molten Fe-Cr alloy has been measured in a Cr2O3, MgO or Al2O3 crucible at steelmaking temperature. O contents at given Fe-Cr components have been lower in order of Cr2O3, Al2O3 and MgO crucible. The present results have been discussed based on the activities of the constituents in pure solid Cr2O3, and FeO-Cr2O3, MgO Cr2O3 and (AI,Cr)2O3 solid solutions.

Jan 1, 2003

By T. Tamura

It is known that the CaO-FetO-P2O5slag system has a wide liquid miscibility gap at steelmaking temperatures and this two-liquid slag phase has many advantages such as high activities of both FetO and CaO and high amount of P2O5. The phosphorus distribution ratio between the two-liquid slag and molten steel was confirmed to be higher than that between CaOsat.-FetO-P2O5slag and molten steel. The two-liquid slag may be useful for dephosphorization of molten steel and reduction of slag volume. Furthermore, the phase equilibrium of two-liquid CaO-FetO-P2O5slagsaturated with MgO was measured to determine the applicability of the two-liquid slag to dephosphorization in steelmaking process. Keywords: slag, refractories, solid solution, two-liquid phase, dephosphorization, steelmaking, phase equilibrium.

Jan 1, 2004

By Jamey Rosen, Georgette Hlepas

"Bluestone Dam is a concrete gravity structure with an overall length of 2,060 feet and a maximum height of 165 feet above the streambed. Several major project modification designs have been implemented and additional modifications are currently in construction and design phases. Due to the various modifications since original construction was completed in 1948, detailed documentation with visualization of the project features is needed. A three-dimensional model of the internal and external features of Bluestone Dam was generated from LiDAR data, survey information, and other data sources. One of the key features of interest in this model is an accurate visualization of over 200 dam anchors based on downhole anchor surveys. The model is accessible in Microstation and Geographic Information Systems (GIS), allowing users to rotate the anchors in three dimensions; view them in the context of geology, internal dam structural features, historical construction records, site photographs, bathymetric data, and instrumentation data. Users can “click” on individual anchors to view associated construction details and open a comprehensive installation packages. The model will be used by the United States Army Corps of Engineers (USACE) as part of a larger Geospatial Data Management System as a historical accounting of the project construction data, and be a long-term living document for use by both design engineers and operations staff to assess dam safety risk and to design future project modifications.IntroductionDuring the life of any project, critical data concerning the construction and performance history are required to be collected and maintained. The data collected prior, during, and post-project construction help with the design process, ensure that the project is built to specifications and is performing as per design intent. During the Post-Implementation Evaluation (an evaluation performed after a major project modification), these data are used to visualize the repairs, verify the construction was performed per design intent, and document the history of the construction phases, associated test results, and overall effect on the project. The project described in this paper is the construction of a system of tools to effectively use these data.Data collected and maintained during the operations phase helps to ensure that the project is continuing to perform as per design and aids in advance warning of any potential failure or required maintenance. Dam Safety, Emergency Management (EM), and Operations and Maintenance personnel can use the system to verify the status of the project in preparation for a high flood event. For example, if there is repair work being performed on a critical feature of the project that would affect the operation of the dam structure during a flood event, Operations personnel would be responsible to update the status of the system such that Dam Safety and EM would be able to identify the feature that is out of service, its date of expected repair completion, and the implications during a flood. In addition, risk assessments typically require a full history of the project and its performance. Any concerns that arise concerning the safety or performance of a project will require a full documented history of the project and its components. Proper documentation and data management are key in this assessment process."

Jan 1, 2016

By Mark C. Holton

The mining industry has recently been. - experiencing a difficult period. Escalating costs, lower grades and deeper level mining, are a few of .the reasons' why interactive graphics or CADD (computer aided design and draughting) systems are increasingly being used. CADD systems which support powerful and flexible mining applications have great potential for making all forms of mining more efficient and effective. There are many application programs which address almost every aspect of mining. Most of these programs originated to satisfy a particular need. Graphics and other features were added until they, reached a point where they were commercially viable as a mining package. Because of their evolution these packages, lack many CADD-type features. Today there are powerful personal computers (PC's) and engineering workstations running the best CADD systems available. These systems, support hundreds of applications in almost every discipline. Mining was until recently not well supported by interactive graphics vendors because of the highly variable nature of mining and the lack of common standards. Users of CADD systems have experienced the benefits of CADD and come to expect similar features from graphic mining packages. Several developers of mining packagers have either attempted to include some CADD features or make their packages compatible with one or other CADD system. Mining can benefit greatly From a combination of interactive graphics (or CADD) and the right mining application software.

Jan 1, 1989

By L. K. Nenonen

"Given the properties, locations and quantities of material to be hauled and the dump locations and capacities, the designer wishes to select the type and number of trucks and loading equipment required. Accordingly, software is being developed to assist in creation of the equipment, material and road network data bases, in selection of equipment, materials and road networks from these data bases, and in evaluation of the expected productivities both in a rapid, non-interactive, approximate fashion and a more detailed interactive fashion which permits the user to act as superintendent, if he so chooses. The basic technology has been developed and applied to an open-pit copper mine and is being refined and generalized for oil sands and coal mining applications.BackgroundA set of mathematical and interactive computer models are under development to aid in the selection of equipment and operating policies for an open-pit oil sands mine being planned by Canstar Oil Sands Ltd. This paper describes the computer models being developed of truck haulage systems. Although the interactive truck haulage model is based primarily on a model developed by the National Research Council in collaboration with Glenayre Electronics Ltd. of North Vancouver and Lornex Mines Limited(2).(3l, substantial changes and improvements are being incorporated to greatly increase its generality re equipment types, road network characteristics, dispatching and supervisory policies, etc. Although this paper is principally devoted to the truck haulage model, discussion is included concerning its interactions with other models."

Jan 1, 1982

By Jerry L. Smith

Industry on a whole has not been very receptive to government prodding to implement waste minimization programs. Waste minimization has the appearance of substantial benefits, however, there are underlying difficulties and suspicions that need to be addressed before industry will support pollution prevention initiatives. They can be summarized as follows: - Human behavior resists change, uncertainty, and unknowns. - New waste minimization techniques are difficult to find and research. - Calculating the true cost of present waste practices as well as new techniques being considered is difficult and time consuming. - Getting a consensus opinion of all the individuals affected on the course or technique to be employed in a pollution prevention program. New software products have addressed many of the problems associated with implementing pollution prevention programs: They contain research on a large number of pollution prevention techniques and case studies; they generally are accessed by EPA ID number, chemical name, or synonym; and some programs have the option to print a comprehensive written user-specific pollution prevention program.

Jan 1, 1994

By S. S. Hedge, J. C. Ferm, J. T. Berger

The coal procedures described in this paper address the problems building a body of coal data that is accurate, precise, readily available, and easy to manipulate. The system is a set of interactive computer procedures consisting of a) data gathering (core hole and geophysical logs, their location, elevation, etc.) and standardized computer printouts, b) the graphic outputs of coded logs (log strips-scale variable) wing on-line electrostatic plotter, c) determination of seam continuity via relative movements of the log strips on an interactive graphic display terminal, d) calculation of the seam parameters (minable seam thickness, volume of non-coal material in the seam, ash and sulfur content of the raw or prepared product, roof and floor characteristics and other attributes relevant to mining), e) posting of seam parameters wing on-line drum plotter controlled by a microprocessor on-line to the minicomputer (PDP- 11).

Jan 1, 1983

Interactive data exploration is essential for visualising grade distribution and geological controls on orbodies. Quick and appropriate computer techniques for making daily 'value adding' decisions include routine imaging of numerical data suc

Jan 1, 1998

By P. R. G. Bak

The integration of interactive computer graphics technology with data analysis tools can assist in the evaluation of deposit models: the super- imposition of mine openings on complex geology can be quickly perceived using dynamic visualisation, colour-coding and transparency control while analysis functions assist in quantifying displayed information. To illustrate the functionality of such integration a research prototype system is presented which allows the interactive visualisation and evaluation of deposit models comprising both structural boundaries and the distribution of continuous properties.

Jan 1, 1992

By Jean-Michel Rendu

Accurate modeling of the semivariogram is an extremely important step in the geostatistical analysis of mineral deposits. Automatic fitting of a mathematical model is often possible but not necessarily desirable. Significant geologic and statistical information must be taken into account in the fitting process, which is not always available to the computer. Manual fitting of the model is, on the other hand, extremely time consuming. Interactive graphics are best suited to optimize the process. A number of interactive methods are described, which are adapted to the modeling of semivariograms in one-, two-, or three-dimensional environments.

Jan 1, 1982