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By X. H. Zhou

Column flotation is being widely adopted for fine particle treatment by the mineral processing industry due to its simplicity of structure, high efficiency and good separation performance. Cyclonic static micro-bubble column flotation (FCSMC) is an innovative column separation technology that has been successfully applied in the coal preparation industry in China. Recently, the application of this equipment has been further expanded to the separation of several minerals such as fluorite, copper, iron, etc. The bottom of the FCSMC is a cone in which cyclonic field is generated when circulating pump is injected tangentially into the column. The unique cyclonic structure is believed to help enhance the column separation performance. Since the FCSMC is a new flotation device, little work has been done to understand the fundamentals of this technology. In this research, a computational fluid dynamics software, ANSYS/ FLOTRAN, was employed to simulate the flow field of a lab FCSMC system (F0.2 m, F3.0 m by length.) The distribution patterns for velocity field and flow field were investigated under single phase condition. It has been found that axial velocity of the slurry decreases and becomes stable along the height of the column from bottom to top, and the slurry performs as a descending flow pattern. Another observation is the velocity fluctuates vigorously near the wall due to wall effect. Compared to axial velocity, the radial velocity distribution is smaller and more complicated. The basic pattern is that on a given cross section of the column radial velocity increases from the wall to the center and it the velocity changes greatly around the center. Under the condition of column height less than 0.8 m, the axial velocity is negative and it directs from the wall to the column axis. When column height is higher than 0.8 m a reverse pattern is obtained, i.e., axial velocity is positive while directing from column axis to the wall. Special efforts were directed to investigate the tangential velocity pattern. Results indicate that the tangential velocity patterns of different cross sections are similar and showed a symmetrical distribution. Tangential velocity distribution concluded two zones: outer whirlpool and inner whirl-pool. And, interestingly, it has been found that on different cross sections the highest tangential velocity always occurs at the same position of the cross sections.

Jan 1, 2014

By H. Kinilakodi

The authors previously developed a methodology that combines injury and citation measures into an overall mine safety performance evaluation tool, called the safe performance index (SPI). It can be easily adopted by mine operators to monitor trends in their injury and citation experiences as a risk assessment method. In this paper, six normalized safety measures and the SPI are used to evaluate the health and safety risk that existed at mines in the two years preceding the occurrence of a fatality. The percentage of mines is given for which the risk was high or where trends of some of the safety measures indicated moderate risk. In 50% of the mines, this mine safety performance tracking method could have been helpful to the companies, state agency or the U.S. Mine Safety and Health Administration (MSHA) in recognizing and addressing emerging problems with actions that may have been able to predict high-risk conditions, the fatality and/or other serious injuries. The approach would have given extra scrutiny to the risk for mines that encompassed 74% of the fatalities during 2007-2010.

Jan 1, 2012

By Stephen C. Tadolini, John Bolton, Bre-Anne Sainsbury, Tom Meikle

"The capacity of ground support components which have been affected by corrosion is reduced and may ultimately lead to dynamic failure of the component and the strata. In order to maintain an effective, long-term ground support system, significant campaigns of rehabilitation are often required in corrosion affected areas which also expose the workers to hazardous conditions. The most common corrosion protection for steel ground support utilises sacrificial systems such as galvanising. Galvanising has previously been proven to be susceptible to some corrosion processes. Stainless steel is the most effective in resistance to corrosion, but can be cost prohibitive, and its mechanical properties often make it unsuited to use in ground support components.Providing an outer protective plastic coating to bolts has proven to be an effective means of protecting the inner steel bar from corrosion. However, these support systems tend to be susceptible to coating damage, and require post cement grouting to provide full encapsulation. In comparison to a standard bolt/resin system, they can be slow to install and expensive. These systems have also been shown to reduce overall load transfer performance of the bolting system.In order provide a higher level of corrosion protection whilst maintaining current installation practices and bolting cycle times, Minova has developed the Enduro™ Steel Ground Support Range. The Enduro™ range consists of standard Minova steel ground support components which have been treated with a unique coating process. The Enduro™ coating has been tested in the harshest of conditions, in laboratory controlled conditions and in underground trials. It has been proven to effectively resist or completely eliminate the formation of corrosion, even in the most aggressive environments. This paper explains the process and provides the details of the laboratory and underground corrosion performance testing carried out on Enduro™ ground support products.INTRODUCTIONTraditionally, the most common form of corrosion protection in steel ground support consists of a sacrificial protective coating such as galvanising (Aziz, et al., 2013). Such coatings have proven to be ineffective in extreme high and low pH conditions with corrosion of the support system commonly encountered. There is also evidence that common forms of galvanising may actually increase the rate of corrosion in certain pH environments. Figure 1 shows typical corrosion and failure of a standard re-bar roof bolt."

Jan 1, 2016

By S. Seetharaman

The present paper presents. the concept of micro-models and illustrates the application of the same in the simulations metallurgical processes. Development of micromodels requires access to accurate thermodynamic, thermophysicaland kinetic information for the relevant systems with suitable models to extrapolate the data as functions of temperature and composition. Experimental measurements and modelling of the thermodynamic properties, sulphide capacities and viscosities of oxide melts carried out in the department are presented. The incorporation of these models in process models, with special reference to ladle refining of steel is illustrated. Typical example of micro-modelling of solid-gas reactions is also presented.

Jan 1, 1999

By Ismet Canbulat

"In order to ensure the stability of roadways, Anglo American Metallurgical Coal (AAMC) has developed a roof support design methodology that integrates analytical, numerical and empirical modelling. This methodology currently is based on a deterministic approach (a single factor of safety against failure is calculated). However, an improved methodology, based on stochastic modelling technique, has also been developed and currently being evaluated. The main advantage of this methodology is that the design is based on the probability distributions of input parameters; thus the outcome is based on a distribution of factors of safety rather than a single factor of safety. An evaluation of factors of safety may also be used to determine the likelihood of failure, which in turn may be utilized to quantitatively determine and evaluate the associated risks in decision making process. This methodology has been evaluated at Grasstree and Moranbah North Coal Mines in the designs of roof support in various critical areas and has been proven to be successful and a better way of determining the roof support requirements.This paper demonstrates the application of this methodology in a design of an install road roof support at Moranbah North Mine, where the 1,750 tonne capacity ''world's highest rated longwall"" has recently been installed.INTRODUCTIONAnglo American Metallurgical Coal Australia (AAMC) operates three longwall (LW) mines located in Central Queensland. There is an increasing emphasis on the reliability at these operations, as the longwalls are getting deeper and facing more geologically challenging conditions. In addition, the Anglo American Vision is to achieve ""Zero Harm"" through the effective management of safety at all businesses and operations. In order to accomplish this vision, AAMC has developed a proactive ground control management system for a safe and efficient production of underground reserves.Proactive ground control management involves understanding the impacts of the geotechnical environment on likely ground behavior, and it consists of approximately 15 major elements. One of the most essential fundamentals of proactive ground control management is to utilize a roof support design methodology that considers different failure mechanisms and also takes into account all important elements. The design methodology becomes even more important when the area in question is a critical area, which is defined as a high risk roadway where any failure may cause increased levels of safety and financial risks to underground workforce and operations."

Jan 1, 2010

By Gary A. Wickham

In the zinc industry, this past decade has seen both prosperity and depression. Significant changes have occurred throughout the world in mining, smelting, refining, and marketing. This paper will review many of the industrywide changes of recent years and the potential impact for 1990s. In addition to an historical review of supply and demand are discussion of technology considerations for zinc and zinc based products, effects of geographical shifting of markets, and projections for the 1990s.

Jan 1, 1990

By N. Ahern, L. Manoukian

"Cyanide is a leaching agent for precious metals commonly used in gold ore processing. Cyanide exists in various forms (including free, complexed as weak or strong complexes, and as ions such as cyanate and thiocyanate), so its detection, speciation and analysis in processing or environmental samples can be complex. This paper will review best practices for cyanide sampling and preservation in the field, interferences and pretreatment methods required prior to sample analysis and analytical methods that are used for cyanide species. Titrimetric, flow injection ligand exchange, spectrophotometric, colorimetric, potentiometric, amperometric, and chromatography techniques will be discussed and their chemistries, detection limits, advantages and limitations will be described.INTRODUCTION Cyanide is well known to be an extremely toxic species. Accurate cyanide measurement in effluent from mines is critical from an environmental perspective. Its measurement is also an important control parameter in the recovery of gold using cyanidation. Cyanide chemistry is diverse and complex, and cyanide analysis can be challenging as a result of and because of limitations in understanding of analytical methods. Various chemical mechanisms can form or destroy cyanide, and the sample matrix or preservation chemicals can also affect analytical results. These interferences make the collection of reliable cyanide measurements challenging and can start as soon as the sample is collected, during laboratory pre-treatment and during analysis. This paper reviews different methods of cyanide measurement. The basic chemistry of cyanide, best practices for sampling and preservation, as well as various methods of analysis will be discussed.CHEMISTRY The complexity of cyanide chemistry is well known (Beck, 1987; Delgado, Botz, Bucknam, Milasovljevic, & Staley, 2008; Botz, Milosavljevic, & Ward, 2013) and is attributed to the ability of cyanide to undergo: •,Volatilization •,Precipitation •,Adsorption •,Complexation with metals •,Oxidation to cyanate, ammonia, or cyanogen chloride •,Reaction with sulfur or sulfide minerals to form thiocyanate •,Redox reactions leading to the formation of cyanogen and cyanate •,Redox reactions (of some cyano complexes) •,Photochemical reactions (of some cyano complexes)"

Jan 1, 2017

By P. C. Schmall

Ground freezing has been used for the sinking of deep mine shafts for more than 140 years. While advances in refrigeration technology have refined the overall freezing operation, the basic ground freezing concept remains the same. This paper presents an overview of the ground freezing process and the unique advantages that ground freezing brings to shaft construction. Design and construction considerations, including instrumentation and monitoring, are discussed. Case studies are presented to illustrate ground freezing applications for mine shaft installation.

Jan 1, 2010

By Jerrold J. Marcus

United states reserves of oil and gas have been steadily declining while consumption of petroleum products has continued to increase. The nut result has been an ever increasing shortfall between supply and demand. This imbalance has been made up by imports of both oil and gas causing a strain on the United States Balance of Payments. To complicate the situation further, exporting nations have recently formed a cartel and dramatically increased the selling price of petroleum products. To meet U.S. energy demand, increased attention has been drawn to the production of synthetic oil and gas from coal. To date, considerable research has been conducted and is continuing on various processes for liquefaction and gasification of coal. Some of these processes are now in the pilot plant stage and at least one demonstration plant has been proposed. The coal conversion complexes envisioned will be very large, requiring substantial capital investments and abundant reserves of coal. Coal production to feed these proposed complexes has been estimated on the order of 75,000 tons per day. With the viability of these projects becoming economically attractive, the Office of Coal Research initiated a contract with Fluor Utah to determine and define the problems of surface mining coal at very high mining rates, under varied physical, geographic, and climatic conditions. The flow of recent events in the Middle East has created a greater sense of urgency for this study.

Jan 1, 1975

By Raja V. Rarnani, Robert L. Frantz

"Co-Directors, Generic Mineral Technology Center for Respirable DustEarly in the 1980s, the U.S. Bureau of Mines initiated the concept of the Generic Center, incorporating it into its mining research program, and in 1983, the Generic Mineral Technology Center for Respirable Dust was established. The Generic Center concept was first envisioned by the U.S. Bureau of Mines as a way to bring together the various different scientific, engineering and medical research interests in the respirable dust area to effect a coordinated and efficient organization for advancing knowledge in that field. The result was a combination of the collective talents and skills of more than 100 scientists, engineers, medical personnel and graduate students, through the formation of a consortium of five major research universities, including medical facilities, to perform respirable dust research. The Generic Mineral Technology Center for Respirable Dust consortium comprises The Pennsylvania State University (with its Hershey Medical Center) and West Virginia University (with its Medical Center) as the lead universities and the University of Minnesota, Massachusetts Institute of Technology and Michigan Technological University as affiliates.Although respirable dust-related disease remains the nation's worst industrial hazard, the fundamental understanding of all aspects of respirable dust associated with the mining and milling industries, including the interaction of dust and lungs, has grown significantly over the past near-decade toward the larger effort to reduce the incidence and severity of disease caused by respirable dust. Continued progress toward making the mine work environment cleaner and healthier remains the immediate objective of the Respirable Dust Center.The Respirable Dust Center's research program and technology transfer activities, described in this paper, exemplify the Generic Center concept first envisioned by the U.S. Bureau of Mines. Interdisciplinary and interactive studies continue to result in significant progress toward making mine atmospheres cleaner and healthier."

Jan 1, 1995

The Golden Cross mine is situated in a sensitive environmental setting on the North Island of New Zealand, about 150 kilometres south-east of Auckland and about 8 kilometres NW of Waihi. The mine is situated in dipping topography, with volcanic ashes making up soils, fault zones running through the area, and rainfall of about 3 m per year on average. Water management is the most demanding environmental challenge on site, and a comprehensive programme has been put in place to address tailings deposition, long term tailings storage, and water treatment during and after operations.   The tailings impoundment is built with an underdrainage system that collects groundwaters and waters that seep through the impoundment. The embankment and impoundment are both built to withstand the Maximum Credible Earthquake and the Probable Maximum Flood. Tailings are treated to remove cyanide and to decrease metal solubility to reduce long term risk to water quality after mining. A state-of-the-art water treatment plant is utilised to treat water from the underdrainage system and water decanted from the top of the tailings pond and stormwaters to remove residual cyanide and metals to extremely high standards with a great deal of reliability and at reasonable cost. Closure of the facility addresses long term post mining water quality issues, and rehabilitation of the area with wildlife habitat as a priority.

Jan 1, 1995

By I. A. Cameron, F. Ham, R. Sriram

"Planned increases in electric furnace productivity and higher matte temperatures needed for the Sudbury Smelter's S02 Abatement Plan, require an improved matte tap hole. Since startup in 1978, the matte tap holes have been incrementally improved by the addition of copper cooling blocks around the refractory tap blocks. These improvements provided a tap block life of about 100 taps per campaign.In July 1993, a prototype matte taphole was installed in Number 2 Electric Furnace to develop the technology to increase tap hole service life. The design was based on a heat transfer model of the tapping process to determine candidate refractory materials and cooler arrangements. The prototype tap hole features increased copper cooling, high conductivity refractories and extensive instrumentation. Eight trial campaigns are reviewed outlining the performance of silicon carbide and graphite refractories and typical heat loads during tapping.IntroductionFalconbridge Limited operates two 36 MYA, 6 electrode submerged arc electric furnaces in Falconbridge, Ontario. The furnaces, commissioned in 1978, smelt a partially roasted nickel-copper calcine, to produce matte for converting and slag for discard. Additional details of the smelter are available in the literature(1-4).Each furnace was equipped with two matte tap holes located in the furnace end wall. Early in the campaign, matte tap holes were identified as a weak area in the furnace which could be improved. From 1981 to 1987, incremental improvements were made to the design by the addition of water cooled copper blocks. In 1993, a prototype matte tap hole was designed and installed in Number 2 electric furnace to develop the technology to increase tap hole service life. Improved service life is required to meet planned increases in electric fWl1ace productivity and the higher matte temperature needed for the smelter's S02 Abatement Plan.This paper reviews matte tap hole development since 1978; outlines the prototype matte tap hole design, refractory selection and installation; and details the performance of the prototype tap hole during the first eight campaigns."

Jan 1, 1995

By M. Savich

A graphical method has been developed for the evaluation of the U.S. Occupational Safety and Health Act Noise Exposure Index and the Equivalent Continuous Sound Level. The method makes use of a noise survey form and a mechanical integrator with two sliders, and is less tedious and susceptible to error than alternative methods. The graphical method is adaptable to various codes for noise exposure and may be used with any instrument that measures noise level. One example of its application to a practical situation in a Canadian mine is given to demonstrate the procedure .

Jan 1, 1978

By J. R. Allen

Environmental laws and regulations have proliferated over the last two decades. 1/ Within the last year, Congress has dramatically expanded the scope of the Superfund program 2/ and has enacted significant new amendments to the Clean Water Act.3/ In addition, EPA has shown no signs of slackening the pace at which it promulgates new regulations to implement statutory programs. The agency projects that over the next few years it will issue approximately 275 new regulations under the statutes it implements. 4/

Jan 1, 1988

By Yu-Min Cheng

Over the past two years, the construction industry has increasingly recognized the benefits and capabilities of building information modeling (BIM) for information integration, visualization and parametric design, reducing the duplication of work and complexity of interface integration, while significantly saving both time and cost. However, due to the variety of participants in engineering projects, the differences between data definition, data format, and data storage increase the difficulty of integrating data from diverse sources. Therefore, buildingSMART has developed a common data schema, called Industry Foundation Classes (IFC), that makes it possible to hold and exchange relevant data between different software applications, to increase the efficiency of BIM work and to ensure a consistent and high-quality output. This paper presents a novel methodology that assists in facilitating the import and export process for parametric BIM objects between heterogeneous BIM systems. This methodology is based on the IFC data schema and includes graphical and non-graphical description data. The objective is to retain the geometry, parameters, unit, texture and links of an object during exchange and sharing to ensure that data integrity is maintained. To sum up, this research addresses the issues of transferring parametric BIM objects between heterogeneous systems to increase data integrity and reduce transfer and integration times.

Aug 1, 2013

By J. G. LECKIE

During the first ten months of 1943 copper was produced at a higher rate than in 1947. However, on Oct. 24 one of the large mines was shut down due to a strike. As of Dec. 31 the strike was still in effect and had already resulted in a loss of production of 50,000 tons of copper. The demand for copper was considerably greater throughout the year than the supply. The price of electrolytic copper delivered at the Atlantic Seaboard refineries advanced from 21.20 to 23.20 cents per lb during the year. This sustained demand for copper, together with the increase in price, has had the natural effect of spurring interest in uncovering new deposits, and in re-examination of known low-grade deposits and old tailing clumps. This is in addition to the usual reevaluation activities which normally result from the constant improvements in efficiency of ore concentration.

Jan 1, 1949

By Adam Turcotte

Mining operations consume a considerable amount of energy, and while reduced energy consumption is desirable, it is not always clear how to achieve this goal. Understanding the opportunities to optimize energy consumption is crucial, and the key to understanding is visualization. One option is the Sankey diagram, which has been used for over 100 years to visualize the flow of energy, materials, or cost through various processes. However, there are drawbacks to this approach that must be addressed. In a Sankey diagram, each flow is represented by an arrow possessing a width proportional to the magnitude of the flow it represents. The diagrams show input flows, how energy is converted and into what form, and also output flows. As per the first law of thermodynamics, the total energy output is equivalent to the total energy input, so any energy that is not transferred to another process is considered to be wasted. These waste flows are depicted in Sankey diagrams and make it straightforward to associate energy sources, sinks and waste flows. Unfortunately, Sankey diagrams do not convey all information required to support practical decision making for redirecting individual energy flows. Based only on a Sankey diagram, it may become evident that a significant flow of waste heat is of the appropriate grade (temperature) and volume to meet an on-site heat demand currently being met with paid-for, possibly carbon intensive fuel. However without augmenting the Sankey diagram with 3D spatial, true geometric analysis, the practicalities of the concept or idea may not be fully appreciated. Another issue with a Sankey diagram is that the magnitude of the energy flowing between processes may have temporal fluctuation or variability on different timescales (diurnal, seasonal, interannual). Currently, Sankey diagrams only provide a static picture of energy conversion and consumption, so that, for example, 4 separate diagrams could have to be prepared for each season. A new energy flow visualization technique which we have called Sankey Trees has been developed. Process locations are defined within a 3D model of the site being studied, and the magnitude of the flow between each pair of processes considered is replaced with a time series. Branches of sustained and diminishing flows are represented through variation of the geometric properties of the branches of the trees. These branches are animated to indicate the direction of flow, and branch joints are used to indicate that a process is transporting one form of energy to multiple processes.

Aug 1, 2013

By L. A. Cisternas, R. I. Jeldres, D. Calisaya

"Flotation of copper-molybdenum sulphide ores in seawater entails critical challenges such as selective recovery of molybdenite, effective pyrite depression, and reducing the lime addition required to reach highly alkaline conditions. It is essential that laboratory flotation tests aimed at solving these problems give reliable, reproducible results and indicate the correct approach for industrial operations. Rougher flotation of coppermolybdenum sulphide ores in seawater was investigated using two different cells: a modified Denver cell and a standard commercial cell. The effect of an organic reagent on the flotation performance was tested, and the fast/slow-floating model was used to describe the results. The modified Denver cell significantly improved the reproducibility of the flotation test results, due to technological enhancements such as the impeller being driven from below without a stator, which enables the whole froth surface to be scraped with a paddle at a constant depth and rate. Organic reagents are a promising alternative to inorganic reagents for depressing pyrite in seawater. However, further studies should be conducted to investigate their impact on molybdenite recovery, as well as to evaluate the possibility of depressing pyrite after molybdenite separation. The fast/slow-floating model was found to be appropriate for describing the flotation kinetics of the copper-molybdenum ores. The parameters are useful for comparing the performance at different conditions. IntroductionOwing to the increasing scarcity of fresh water, the use of seawater mining and mineral processing is becoming increasingly important (Cisternas and Moreno, 2014). Seawater can be desalinated by reverse osmosis, but this involves considerable costs, limiting it to the big mining companies (Akgul et al., 2008; Leidner et al., 2012; Ghaffour, Missimer, and Amy, 2013). Furthermore, desalination has environmental consequences (Lee, Arnot, and Mattia, 2011); for example, a desalination plant designed to process 2.5 m3/s requires an electrical energy supply of around 30 MJ/s. To supply this power demand, a thermoelectric plant burning bituminous/sub-bituminous coal mixtures at a thermal power generation efficiency of 35% might release around 1200– 1500 t of CO2 per day. Furthermore, the effluents from desalination plants are typically discharged into the sea, and their high temperature and ionic content inevitably modifies the marine environment, with unknown consequences. The direct use of seawater is, therefore, more attractive, but it also poses major challenges since seawater contains ions that adversely affect mineral recoveries. In particular, in the flotation of sulphide ores in seawater, the floatability of molybdenite is depressed (Castro, 2012; Laskowski, Castro, and Ramos, 2014)."

Jan 1, 2017

By James Bennett, Jinichiro Nakano, Anna Nakano

Previous empirical research demonstrated that by mixing gasification and metallurgical slags at a specific composition in a CO2 enriched environment, enough exothermic heat would be generated to transform CO2 to CO. The process capacity may be limited by the availability of the slags, however, it could be used to supplement existing energy or chemical production to reduce overall carbon emission. In this study, computational simulations were performed to explore optimal process conditions based on effects of individual slag constituents and thermal input for maximal gas conversion rate, heat production, and volume increase. In simulated conversions of CO2 to CO and H2O to H 2, comparisons were made by varying CaO, FeO, versus V2O3 slag constituents. The result indicated the optimal slag composition may be obtained by appropriate source selection and mixing of gasification and metallurgical slags in order to maximize carbon reduction and/or H2 production.

Mar 1, 2017

By Roy A. Grancher

HAPPY BIRTHDAY Not only is 1971 the Centennial Year of the AIME, but it also marks the One Hundredth Anniversary of the United States Portland Cement Industry. On September 26th in 1871 David O. Saylor of Allentown, Pennsylvania, received his patent Numbered 119,413 for the manufacture of portland cement. "Cement" had been used in the United States before that. This was, however, natural cement - a direct product of rocks as found in nature, usually burned at low temperatures in open kilns. During the early 1800s this natural cement played an important role in such projects as the building of the Erie Canal. It was only after the Civil War that small amounts of high priced portland cement was imported from Europe. The successful use of this material in construction led to Saylor's experiments and subsequent patent for the manufacture of a scientifically controlled product in this country. These one hundred years have witnessed four major "ages" of cement . . . three of them occurring in the last quarter century since World War Two. The first age was the "Age of Development", a seventy-year period which saw the growth of cement and its concrete end uses as major construction materials. Next followed a period called the "Age of Demand" when, after the war, cement became in short supply relative to large building requirements. In effect a cement shortage existed. The decade of the Sixties proved to be the "Age of Reaction", with its courses of action coming in response to the problems that arose when the industry's expansion programs provided too much capacity. Today cement, and the concrete industries, find themselves entering the "Age of Reason". Overcapacity, low price, rising costs, and poor returns are several of the reasons behind that name, As these industries face the construction challenge of the Seventies, and beyond, the application of basic management principles (otherwise known

Jan 1, 1971