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By D. Sanguinetti, A. Consigny, M. Nodwell

"Alkali precipitation of dissolved metals is an inexpensive but non-selective means of treating mine wastewater. Alternatively, sulphide precipitation can treat to below parts-per-million concentrations while selectively recovering valuable metals. While technically feasible, sulphide treatment of dilute waste streams increases the size and cost of the plant relative to the metals loading. Ion exchange has been applied at two separate sites to pre-concentrate nickel containing wastewater prior to recovery in smaller and more cost effective sulphide precipitation circuits. The result is a dual-circuit system that can maintain high selectivity and reduce overall facility cost while meeting strict effluent regulations.INTRODUCTIONAlkali precipitation using lime is the most common method of treating mining effluents for dissolved metals removal. This method is generally sufficient for waste streams containing mixed metals of little value, and for meeting modest metal concentration limits in the final effluent. Due to the non-selective nature of the lime process, the produced metal hydroxide sludge is of little value. All metals are removed together in a sludge product which cannot be re-processed for further value recovery.By contrast, sulphide precipitation can be used to selectively remove and recover valuable base metals (such as copper, zinc, nickel and cobalt), since the sulphide will preferentially target these metals without reacting with less valuable metals (such as iron and aluminum). The low solubility of the metal sulphide solids also supports the removal of base metals to lower concentrations than can be achieved with alkali precipitation in addition to other benefits discussed more fully in a prior paper (Bratty, Lawrence, Kratochvil & Marchant, 2006). The corollary to this solubility feature is that sulphide precipitation can function on influent streams containing low (< 10 mg/L) metals concentrations to meet very low parts-perbillion final effluent concentrations. Reagent overdosing is also minimized when compared to alkali precipitation."

Jan 1, 2012

By J. Bakos

Solar Hydrogen Energy Corporation (SHEC Labs) recently constructed a pilot-plant to demonstrate a Dry Fuel Hydrogen Generation System that is powered primarily by sunlight focusing-mirrors. The pilot-plant consists of: A Solar Mirror Array and Advanced Solar Concentrator and Shutter System; and two thermo-catalytic reactors to convert Methane, Carbon Dioxide, and Water into Hydrogen. Results from the pilot study show that Solar Hydrogen generation is feasible and cost-competitive with traditional Hydrogen production. More than 95% of Hydrogen commercially produced today is by the Steam Methane Reformation (SMR) of natural gas, a process that liberates Carbon Dioxide to the atmosphere. The SMR process provides a net energy loss of 30 to 35% when converting from Methane to Hydrogen. Solar Hydrogen production provides a 14% net energy gain when converting Methane into Hydrogen since the energy used to drive the process is from the sun. The environmental benefits of generating Hydrogen using renewable energy include significant greenhouse gas and criteria air contaminant reductions.

Jan 1, 2005

By S. Shairp

At the Hudbay zinc pressure leach plant, filtration and washing of the second stage leach slurry takes place on a vacuum belt filter prior to disposal to tailings. Due to periods of poor filterability, laboratory studies were undertaken to investigate the effect of temperature of the filter feed slurry, and to compare filterability to the resulting cake particle size distribution.

Jan 1, 2014

By M. G. Lipsett

One challenge in applying information technologies in Mining is building a business case. In Mine Maintenance, there is a complex flow of information that contributes to making informed business decisions. By understanding those information relationships and the cost of wrong decisions, analysts can estimate the value of information flow. Developers can then ensure that systems deliver key information in an accurate and timely way. In this paper, general maintenance decision-making is discussed, with examples of how model-based analysis can improve the information delivered to decision makers.

May 1, 2001

By W. I. van Drunick

The Anglogold Ashanti (AGA) Navachab single stage SAG mill has provided an excellent setting for incremental optimization. Over the past decades, several interventions have resulted in marked improvements in specific performance; including steel ball scat removal, re-design of the mill lifters, replacement the pebble crusher and cyclone cluster, as well as the use of a vibrating screen in place of a discharge trommel. Recent initiatives now include an operating fine DMS circuit, studies on pre-crushing of the ROM feed and also fine-screening as an alternative to hydrocyclone classification. The current optimized state of the Navachab mill allows it to operate at approximately 20% higher efficiency when compared to mills of similar shell dimensions in gold mining, treating similar ore. This paper describes the systematic improvement of the SAG circuit to its current state.

Jan 1, 2012

By L. Tikasz

The primary purpose of ore hauling model studies is to capture the variability of the ore delivery ? stockpiling process in order to improve the estimation of equipment capacities and achievable throughputs. The operation of a mine-to-site ore delivery system is the subject of a number of challenges. Typically, ore is hauled by a given combination of trucks, conveyors and trains. In addition, ore loading, ore transferring to another means of delivery, stockpiling, reclaiming, and further deliveries involve many other types of equipment. The concurrent operation of all these units is scheduled; nevertheless, they are subject to planned maintenance and random breakdowns. To support our engineering design work on ore hauling operation, discrete event type models were built for each specific task. Then, due to recurring demands, an ore hauling library was gradually compiled. The now available model library allows fast and efficient simulation of various mine-to-site hauling arrangement, adaptable to various mining and mine construction operations (e.g. bauxite, iron ore, copper ore and coal).

Aug 1, 2013

By Q. G. Reynolds, R. T. Jones

"Residence time distributions are well defined for batch and continuously stirred reactors. However, there exist many smelting furnaces that do not fit either of these classifications. A mathematical description is presented for the case of a furnace that is fed continuously, but where the liquid slag and metallic products are tapped intermittently. The effects of slag and metal tapping intervals and the fraction of liquid retained in the furnace, are shown to have a significant effect on the residence time distribution.INTRODUCTIONThere are some processes in which the time spent by the feed material in a smelting furnace plays a significant role in determining the extent of the reactions between metal and slag and influences the degree of settling of metal droplets from a molten slag.Residence time distributions are well defined for batch and continuously stirred reactors. However, there exist many smelting furnaces that do not fit either of these classifications. Here we will focus on producing a mathematical description for the case of a furnace that is fed continuously, but where the liquid slag and metallic products are tapped intermittently. The effects of slag and metal tapping intervals and the fraction of liquid retained in the furnace, are studied.Previous work (Jones, la Grange and Assis, 1997) has studied the effect of retention time on the degree of cobalt recovery achieved in a slag reduction process. In that work, a method was proposed for the calculation of the mean residence time of the contents of a pilot-plant furnace. That approach is to be extended here for the purposes of providing a more general design or scale-up tool.The maximum allowable depth of molten material in a given furnace is affected by such factors as the desired batch size (or the size of the ladles) and the pressure of the molten material that the tap-hole and surrounding system can withstand. Within these constraints, there might be some scope for choice of taphole position. The effects of this choice need to be understood mathematically."

Jan 1, 2012

By Jas. E. Thomson

"The Kirkland Lake-Larder Lake gold area is in northeastern Ontario and is a continuation of the ore-bearing belt that extends across northwestern Quebec through the Rouyn, Cadillac, Malartic, and Bourlamaque areas. It is the oldest mining camp along this famous mineral belt. Gold discoveries were first made at Larder Lake and Swastika in 1906, but it was not until 1913 that important developments at Kirkland Lake created a real interest in the country. Total gold production of the camp passed the million dollar a year mark in 1920 and increased in amount yearly until the advent of the second World War when there was a falling off due to labour shortage. The Kirkland-Larder camp ranks as the second largest gold producing area ' in Ontario. To the end of 1944, twenty-two mines in the area had produced bullion valued at $515,631,428 and ten mines had distributed dividends amounting to $205,981,116. The average grade of the ore milled in this period has been $15.17 a ton for the mines in the Kirkland Lake area and $6.49 a ton for the mines at Larder Lake.ROCK FORMATIONS OF THE AREAIn a general way the rocks of the country may be divided into the lithological groups indicated on the accompanying geological sketch map. This map has been compiled largely from recently issued geological sheets of the Geological Branch of the Ontario Department of Minest. Owing to the present difficulty of separating the formations of the Larder Lake country into the twofold age divisions of Keewatin and Timiskaming, the usual custom in the past, a lithological grouping of formations has been adopted. The age terms 'Keewatin and 'Timiskaming' are loosely used in this article to express the often used but not necessarily accurate distinction between the main groups of older strata."

Jan 1, 1954

By J. H. Sokolowski, R. I. MacKay

The level of Si and Cu in the 3xx series of alloys affects the volume fraction of the a-Al dendritic phase and the Al-Si eutectic phase. The volume fraction of these phases in turn affects the feeding conditions during solidification and ultimately the Area Fraction Porosity and Mean Pore Diameter measured in the as-cast structure. This work sets out to establish the relationship between the volume fraction of the a-Al dendritic phase and the Al-Si eutectic phase and the resulting porosity that forms on the Monotonic and High Cycle Fatigue properties. The alloys in question are the Al-9%Si-l %Cu and a Al-7%Si-4%Cu alloys which were cast into V8 performance engine block castings and then heat treated to achieve desired mechanical properties. The engine block castings provided the mechanical and metallographic test samples analyzed for this work.

Jan 1, 2006

By Gerry Roblesky

"IntroductionWestar Mining Ltd. is Canada&apos;s largest producer of metallurgical coal for the export market. It currently operates two mines, the Balmer Mine at Sparwood, British Columbia producing 6 000 000 tonnes per year and the Greenhills operation at Elkford, producing 2 100000 tonnes per year. Approximately 1600 people are employed between the two mines which operate independently but share common administrative services.Like most mining companies in Canada over the past three or four years, Westar has faced rising production costs along with flat or declining prices and demand for its products. In order to survive under these conditions it has become necessary to strive for decreased costs in any way possible. Over the past two years there has been a widespread introduction of microcomputers across the company. In order to satisfy increasing demand for accurate and pertinent information while at the same time increasing productivity, the microcomputer has become an invaluable tool.This paper describes some of the problems faced by a mine maintenance department in this operating climate and how they were solved with the help of a microcomputer. It also describes some of the problems that may be encountered both with equipment and people and recommends some ways that these might be minimized or avoided. Finally, an assessment of whether or not the move to microcomputers was a current and economical one, and a brief description of future plans and projects is given.The Maintenance OrganizationIn order to appreciate fully the role that microcomputers are playing within the Maintenance Department at Westar Mining, a little background on the organization and operating philosophies is in order. Most of the comments apply directly to the Balmer operations, however, the Greenhills operation is similar in concept.The mine maintenance organization operates on a fleet based concept with these departments reporting to the maintenance superintendent: haulage trucks, shovels and drills, loaders and Caterpillar equipment, maintenance services, and rebuild services.Each of these departments is headed by an assistant superintendent and is responsible for all maintenance on the equipment on the respective fleet. Shift foreman, planners, specialists and clerical staff are assigned to each fleet. A central engineering and administrative group consisting of one engineer and three clerical positions is responsible for maintenance engineering and centralized administrative services"

Jan 1, 1988

By G. W. Zhang, Changsha Research Institute of Mining and Metallurgy, X. Xiao, Y. Long, L. L. Huang

"The paper presents a scale-up and design method of vertical screw stirred mill, in which the closed circuit of mill and hydrocyclone was assumed as one factor, theoretically regardless the affects inside system of the mill and hydrocylone. The specific energy is chosen as a scale-up criterion, based on the premise that when fed the same feed material, mills of different sizes delivering the same specific energy will yield products.Batch grinding tests are conducted to determine the specific energy, and combined with industrial production data, scale-up and design of vertical screw stirred mill for industrial production are accomplished. Having developed this method for the vertical screw stirred mill used in regrinding duty of iron ore in Ma Steel, it has now been successfully applied in other installations.INTRODUCTIONThe Towermill was developed in Japan in the 1950s, by the Tower Mill Kubota Corporation, it was fine and ultra-fine grinding mill of the metallic ores and concentrates. Due to the rapid development of metal mining and useful minerals disseminated fine, fine grinding and ultrafine grinding equipment has also been more wide used in minerals processing industry. Typical fine and ultra-fine grinding mil are the Vertimill and Stirred Media Detritor (SMD) Mill of Metso, Eirich Towemill, Outotec HIGmill, FLSmidth VXPmill, Xstrata Isamill and the vertical screw stirred mill (JM) of CRIMM, etc.JM series of vertical screw stirred mill were invented by Changsha Research Institute of Mining and Metallurgy in the 1980s. Energy saving and consumption reducing have been achieved through the optimization and engineering practice. More than 500 units JM series of vertical screw stirred mill are used in the iron ore, copper ore, copper-molybdenum ore, molybdenum ore, Pb-Zn ore and Au ore."

Jan 1, 2016

By Ursula M. Franklin

Old iron nails are one of the most common objects which entice the general public to ask questions about the history of metallurgy. There is a lot of history in old nails - history of the manufacturing industry, and social and economic history. Nails, therefore, are fine teaching tools; whether students have to acquire metallurgical skills or explore the structure and properties of wrought iron, whether they want to look into the history of inventions and the development of machinery, studying nails tells a story better than any teacher or any book. I have used this approach often and the following note is based on several student projects, particularly the work of Carmina Herrero and Vicky Marchant. Nails, those essential metallic fasteners, have long been with us. Their size, shape and design is basically a compromise between the makers&apos; ability to control and manipulate material and the demands of the intended application. There were copper and bronze nails in antiquity, but in this paper I want to deal only with iron nails. In Rome, iron nails were common, and Cleere carried out the fine metallographic investigations on a large stock of nails recovered from a Roman fort site in Scotland. Those nails were hand forged; sorting them at the site on the basis of length, shape of head and shape of shank (in cross section) indicated that there seemed to have been some nail standardization. It appears that the Roman smiths used a series of heading dies starting with a 1/s-in. size. Each successive size increased by approximately 1/16-in. The metallographic inspection of the microstructures of the nails showed that the smaller nails were made in the one operation; i.e. both the tapering and the formation were accomplished on the heated rod without reheating. However, in the case of the larger nails, the nail had to be reheated for the tapering after the head had been forged. Most nails were tapered on all four sides of the shank and the shanks were square in cross section; only one group had rounded shanks. Most heads were flat disks, but in one group the heads were pyramids and another group had conic heads. Figure 1 shows the procedure used to produce the pyramidal heads. Obviously, Roman nail making was sophisticated and each nail design was meant for a particular use.

Jan 1, 1999

By M. Ruel

In today&apos;s highly competitive worldwide market, it is becoming extremely important for managers to make sure that all resources are used where needed the most. That way, all resources are generating added value, process control equipments are maintained in an optimal state for best performance, and final product is produced at least cost. Performance monitoring is the only way to ensure that everyone is working on top priorities toward the same goal. How can we add value to these warehouses of data? The data is there and the information is hidden; it is just waiting to be extracted. A process performance monitoring system is able to determine if a loop, a system, a unit, or a plant meets the expected performances. The system prioritizes the areas that need attention. It also provides historical reports of the plant status by areas, by loops, and by identified problems. This information is provided to different categories of users in an appropriate format for each one. The system also includes diagnostics and tools to detect and analyze problems.

Jan 1, 2007

By J. B. Kwon

For improvement in the productivity of tall building projects, table formwork is one of the main methods that have been adopted for slab formwork. Because the table formwork method is an equipment-oriented construction method, the type of lifting equipment and method of operation considerably affects the productivity and cost of the table formwork. It is also important to make an equipment input plan for completing the table formwork within the time given, according to the structural construction cycle. For performing the table formwork, a tower crane or an independent lifting system, and shifting trolleys, are required. However, if an inefficient equipment input plan is made, exorbitant cost may be incurred. Therefore, the purpose of this study is to analyze the productivity of a table formwork, considering the type and number of lifting equipment and the number of trolleys inputted, and to suggest quantitative data for making a cost-efficient equipment input plan within the construction duration given. It is expected that the results of this research will be utilized as a basis for cost-efficient equipment input planning.

Aug 1, 2013

By Jun Dai

Based upon research findings from several countries, the combination of microwave and mechanical means to break hard rock holds promise for the future. To achieve this goal, it is essential to understand the laws governing strength reduction of hard rock, such as granite, induced by microwave irradiation. Two aspects to consider are: 1) laws associated with the tensile strength of hard rock after microwave irradiation and 2) the sensitivity of different types of rock strengths to microwave energy. In this study, granite with a range of tensile strengths was exposed to microwaves for various time periods to compare the response of rocks with different strength values exposed to the same microwave irradiation. In addition, a method based on hotspots is presented to explain the mechanism by which granite strength is reduced by microwave irradiation. Granite extracted from Qinling Mountain in Shaanxi Province, China is used in the research. ?50 × 50 mm cylindrical granite specimens were exposed to microwaves at a specific power level. The strength values of the heated granite specimens were compared with those of unheated specimens. Through the comparison and analyses, relationships were determined between 1) reduction in granite strength and microwave irradiation time period, and 2) granite strength and sensitivity to a given energy of microwave irradiation. Finally, a mechanism to explain the experimental results is proposed. Research findings will aid in the design of a microwave + machine rock-breaking system for use in rock breakage in underground mines at depth and for future mine applications on earth and other planets. In addition, the experimental approach could be used to test other rock types to further our understanding of rock damage induced by microwave irradiation.

Aug 1, 2013

By F. Chiesa

The permanent mould process, which is a favoured process for producing premium quality aluminium casting, is rarely used to produce magnesium alloy parts. This may be attributed different factors such as: the reservation with which the automotive industry considers using magnesium in structural castings; also the relative hot shortness of most magnesium alloys when compared to aluminium A356/357 is another factor. A third reason stems from the fact that the "heat content" of magnesium is much less than that of aluminium, resulting in the difficulty, for a relatively slow process such as permanent mould (versus pressure die casting), to reach a mould dynamic equilibrium temperature sufficiently high to avoid premature freezing and misruns. The present work will address this problem by carrying out controlled cycling of a laboratory mould, poured with aluminium and magnesium alloys. The influence of insulation of the mould and artificial electric heating on the run-in mould temperature will be determined experimentally. A thermal model will be sought for these thermal devices that will allow to predict the thermal behaviour of moulds of different geometry before a single casting is poured. The model will be tested on an industrial casting in a workshop environment.

Jan 1, 2006

By S. Hill

For a mining operation, the determination of the best place to build haul roads is typically done by hand, or with the assistance of rudimentary shortest path optimisation algorithms. Straight line, point to point, modelling of costs is often used with distances multiplied by constants that are based on rise of the road between the points. Failings of this approach are that straight line approximations are notoriously poor as they do not take into account areas where a truck cannot travel. In addition, the rise and fall of the road may vary considerably over the truck journey meaning acceleration/deceleration and varying truck speeds are not taken into account. Lastly, the use of rudimentary optimisation algorithms means properties a truck must obey such as minimum turning circles, line of sight restrictions or even that the truck must travel forward at all times are not taken into account. Thus solutions generated may not be feasible, let alone optimal. In this paper we discuss a state of the art parallel Artificial Intelligence tree search technique for solving haul road location problems. As well as the above properties, factors such as road utilisation, cut and fill, and construction costs are taken into account. The combination of advanced modelling and fast computing and optimisation techniques produces significant benefits both in terms of time to generate roads and cost savings. Preliminary results where this method has been used are discussed.

Aug 1, 2013

By Keith Haddock

"The Sheerness Mine, a new surface coal mine located near Hanna, Alberta, went into full production in mid-1995. The mine, which is operated by Luscar’s subsidiary Forestburg Collieries (1984) Ltd., has the design capacity to supply up to 2.1 million tonnes of sub-bituminous coal per year to the adjacent Sheerness Generating station under a 30-year contract. This paper documents the construction phase of this project and highlights the major equipment purchases as well as the construction of the mine facilities. The paper also focuses on some of the areas where cost savings have been achieved that have allowed the mine to come on stream six months ahead of schedule, and under budget. Project ReviewMine DescriptionThe Sheerness Mine is located 25 km southeast of the town of Hanna in southeastern Alberta (Fig. 1). The mining property occupies the western portion of the Sheerness CoalField and borders the Montgomery Mine, operated by Manalta Coal Ltd. in the east, and Highway 36 in the west. The Montgomery Mine and the Sheerness Mine exclusively supply the total coal requirement of the adjacent Sheerness Generating Station. The station is owned jointly by Alberta Power Limited (APL) and TransAlta Utilities Corporation (TAU). APL is the operator. Manalta’s Montgomery Mine has supplied coal to the Sheerness Station since its opening in 1986. Coal is shipped by truck from the mines over a network of haul roads to the coal receiving hoppers located on the east side of Highway 36."

Jan 1, 1997

By George B. Saunders

It is the purpose of this paper to point out conditions as they exist in the merchandizing of coal, to compare these conditions with methods in use by competitive producers of coal substitutes, and to present briefly some suggestions which may help the individual operator to market more coal in the immediate future, while we are waiting for the scientist and research worker, who are now busy on coal betterment , to produce in a practical way the results which they now write about in such glowing terms. While it may be unnecessary to call the attention of coal operators to the present deplorable condition of the industry, it might be well to impress upon our members in other branches of mining, as well as upon the public at large, the seriousness of the situation. Emerging from the war and the period of reconstruction that followed, the coal industry found itself with too many mines and too many men for normal conditions. To make matters worse, the interruptions in deliveries caused by strikes, the unfavourable publicity caused by socialistic propaganda, and the repeated governmental investigations, made the market a fertile field for coal substitutes which were not so handicapped. These substitutes were well advertised, and were marketed in an up-to-date manner, furnishing an example from which the coal operator could well profit. Now, whether or not there is agreement as to the cause or causes of this condition, there can be no doubt that we are today face to face with the fact that the sale of coal has not kept pace with the sale and use of other commodities. Had it done so, we would ere this have been able to take care of the surplus labour and work our mines at least approximately full time.

Jan 1, 1929

By R A. Stevenson

The purpose of this paper is to outline a recent development in ground fault protection. The paper deals with the A problems of both grounded and ungrounded systems, with regard to hazards to personnel and equipment, and shows that the increased sensitivity and speed of operation of this new detector results in increased safety to personnel and reduced stresses on equipment, and permits the detection of leakage currents before they become serious faults. The detector can be applied to all distribution systems, either A.C. or D.C., up to 15 kv., and the detector itself can be tested at regular intervals without interrupting line circuits. T HERE is always controversy among engineers as to whether distribution systems should be grounded or ungrounded. There are many experi-enced engineers on both sides of this controversy, and each have valid reasons for their choice

Jan 1, 1964