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By G. Azimi, C. A. Ang, F. Zhang

"Nickel recovery from laterite ores generates large amounts of solid and liquid wastes. This is primarily due to the low concentration of Ni (about 1.4 wt%) in the feed ore to the High-Pressure-Acid-Leaching (HPAL) process. It is known that the HPAL residue contains a high concentration of hematite, a commercially important source of iron in the steelmaking industry. However, the balance is natroalunite, containing sulfur, which is a detrimental element in the steelmaking process. Hence, to make the HPAL residue a suitable feed for steelmaking, natroalunite must be removed. The current work is focused on: 1) a thorough characterization of the HPAL residue obtained from Vale, and 2) a systematic investigation of an alkaline leach process to remove natroalunite. The characterization results indicated that there are about 83 and 12 wt% hematite and natroalunite in the HPAL residue, respectively. The leaching results indicate that sodium hydroxide is the best leaching agent, which results in 55 wt% reduction in the sulfur content. The results of this work enable the conversion of an otherwise waste product into a useful feedstock for steelmaking. Furthermore, this project could potentially have significant environmental benefits by reducing the amount of residue produced during the HPAL process.INTRODUCTION Conventionally, crude steel has been obtained by reducing iron ore containing oxides such as hematite (Fe2O3), magnetite (Fe3O4), and wüstite (FeO) in a blast furnace with coke. The product is then refined in a basic oxygen furnace to produce steel with useful properties (McGannon, 1969; Turkdogan, 1978). Steel has been sought for its desirable properties and its application is widespread throughout modern civilizations. Surpassing the growth rate of other materials, the annual demand of steel has increased at a compound growth rate of 5% over the last 20 years (Baddoo, 2008). The global demand for steel was reported to be 1501 Mt in 2016 and demand is expected to double by 2050 (Cullen, Allwood, & Bambach, 2012; World Steel Association, 2016). In recent years, to meet the rapid growth of demand, secondary resources for iron have been identified as strategic sources of iron (Das, Kumar, & Ramachandrarao, 2000; Li, Sun, Bai, & Li, 2010; Matschullat et al., 2000). The residue produced from high-pressure acid leaching (HPAL) of laterite ore has been identified as one of the important secondary sources of iron (McDonald & Whittington, 2008). Laterite ore represents 60% of the world’s nickel resources and accounts for approximately 40-50% of the world annual nickel production (U.S. Geological Survey, 2016). Therefore, the amount of iron residue produced by the process is substantial and its utilization will produce both economic and environmental benefits."

Jan 1, 2017

? A BARGE WILL BE INSTALLED IN THE BOTTOM OF A COMPLETED PIT. ? THE PROVEN BAUER CUTTER TECHNOLOGY WILL BE INSTALLED ON THE BARGE AND A DEWATERING PLANT WILL BE INSTALLED NEAR THE BASE OF THE PIT RAMP. ? THE WATER LEVEL IN THE PIT WILL BE RAISED BY 20- 40 METRES AND REMAIN CONSTANT OVER DURATION OF MINING. ? THE CUTTER WILL BE LOWERED TO MINE 10 METRE DEEP BENCHES ON A CHECKERBOARD PATTERN TO AN ULTIMATE DEPTH OF 200 METRES. ? THE 5? MINUS CUTTINGS WILL BE PUMPED TO THE DEWATERING PLANT, DEWATERED, AND TRUCKED TO SURFACE.

May 1, 2003

By Jan E. Nesset, James A. Finch, Frank Rosenblum, Rebecca Payant

"Under certain conditions of moisture and oxygen, sulphides can spontaneously heat, a phenomenon known as self-heating. In this paper, we test a hypothesis that galvanic interaction between some sulphides can promote self-heating. Galvanic interaction is controlled by restpotential difference between minerals and their surface area of contact (particle size). In order to decrease rest-potential, four sulphides were tested: pyrite, chalcopyrite, sphalerite and galena. Two series of samples consisting of mixtures of two sulphides, each representing a mass fraction of 50 %, were run in standard self-heating tests. The first series comprised five mixtures, two with low rest-potential difference (pyrite-chalcopyrite and chalcopyrite-sphalerite) and three with high rest-potential difference (pyrite-galena, chalcopyrite-galena and pyrite-sphalerite). The second series was performed on a pyrite-sphalerite mixture at four particle sizes (80 % passing 850 µm, 300 µm, 75 µm and 38 µm). The first series showed that the individual sulphides and the mixtures of low rest-potential difference did not self-heat but the mixtures of high rest-potential difference did self-heat. The second series showed that self-heating increased inversely with particle size (increased specific surface area) and revealed that it was the fineness of the pyrite (high rest-potential sulphide) that governed the self-heating effect, indicating the rate-limiting step is the reduction reaction on pyrite (cathodic mineral). The increase in self-heating with high rest-potential difference and increasing particle fineness supports the hypothesis that galvanic interaction contributes to sulphide self-heating. A possible mechanism based on the hydrogen sulphide hypothesis is proposed where the reduction reaction at the cathodic mineral surface is ferric to ferrous. The understanding gained will be of interest to those involved in storage, shipping and disposal of sulphide minerals.INTRODUCTIONSulphide mineral ores are the major source of most base metals such as copper, zinc, nickel and lead. Once the ore is extracted, the sulphide minerals are liberated by size reduction (crushing and grinding), concentrated by flotation, and the concentrates sent for further processing to extract the metal (smelting and refining). At the various stages from mining to concentrate shipment and tailings storage, the sulphides are exposed to a variety of environments, which under certain conditions of air (oxygen), humidity and temperature can cause them to heat. Since no external heat source is involved, this pyrophoric process is known as spontaneous heating or, more commonly, self-heating. The self-heating of sulphides is associated with oxidation reactions under moist conditions. If the heat generated is greater than the heat dissipated, the sulphides will self-heat and the material temperature will rise. This can make working conditions potentially dangerous as oxygen is consumed from the surrounding air and significant quantities of sulphur dioxide (SO2) can be released (Ninteman, 1978)."

Jan 1, 2011

By Charle Pelley, Kosta Fytas, Peter Calder

"A computer model has been developed which is capable of evaluating alternative production schedules (long- and short range) of an open pit mine once the ultimate pit limits have been defined. The model user can choose the best alternative according to cash flow considerations and the particular mining conditions. The model involves a combination of simulation for long range production scheduling and linear programming for short range scheduling. IntroductionMining of mineral deposits in such a fashion so that, at depletion the maximum possible profit is realized, has been a very old problem of the mineral industry. In the past, when high-grade ore reserves were readily available and profits were very high, no question of optimum profitability was raised.However, recently the complexity of both open pit and underground mining has been increased tremendously. The additional problems of continuously rising production costs on one hand and of depressed metal prices worldwide on the other, have been demanding optimum profitabiliy from every mining venture .Particularly in the area of open pit mining, the sequence of ore and waste extraction has now become very important since the size of the pits and of the mining equipment has increased enormously. The process of open pit mining involves a continuous change of the open pit surface and there are many feasible plans of extraction which lead to the same final pit shape (ultimate pit limits). Each of these feasible plans generates a production schedule over the entire mine life, which mayor may not be optimal."

Jan 1, 1987

By I. Tinto

"IntroductionEnvironmental pollution problems, caused by gases or effluents, by high noise levels or from air borne dust, are placing increasing demands of the operators, from statutory authorities, and from the general public, to adopt more stringent dust control measures. This requires that a successful plant dust control program be an integral part of any plant operation. While a successful environmental program is a key factor in maintaining productivity and good labour relations, anticipation of future environmental regulations during the plant design phase can avoid the high cost of plant upgrading, or dealing with pulmonary conditions in the work force in subsequent years.Particulate removal, conventionally called dust collection, involves the removal of coarse- and fine-particulates from the airstream. Although generally limited to that required for contro!Hng plant generated air emissions, particulate control equipment also has a wide application for air cleaning and filtration inside the plant, as well as for recovery of usable products.In the late 1950s and early 1960s the public became more concerned with the problems of air pollution. This increasing concern was stirred by an awareness of the extremes to which water pollution had progressed in many of the rivers and lakes, by increasing perception of air pollution as detected by visible smog and harsh chemical odors, by the alarming rate of increase of smog plagued cities and communities, and by specific incidents where ill health could be traced to specific episodes of air pollution. Particle size is perhaps the most important single factor affecting particulate control. Large particles (over 5 microns) constitute the major mass fraction of most sources of emission and economical control equipment dqes exist for their efficient control. However, while these larger particles frequently represent the source of soiling and unsightly smoke plumes, they are not a major health problem as they tend to settle relatively quickly, are more easily scrubbed from the atmosphere by rain, and are not able to penetrate the respiratory system. By far the most important form of particulate air pollution is the fine particulate, (below 3 microns) which is harmful to the pulmonary system. The adverse effects caused by this particulate matter on human health are for the most part related to injury to the surfaces of the respiratory system. Particulate material in the respiratory tract may produce injury itself, or it may act in conjunction with gases, altering their sites or their modes of action. A combination of particulates and gases may produce an effect that is greater than the sum of the effects caused by either individually (i.e. synergistic effect)."

Jan 1, 1989

By Mory M. Ghomshei

"The cost of deep underground mine cooling depends on a number of geological, environmental and economic factors such as the temperature gradient in the mine, the outside air temperature, and the local price of energy. While geological factors, being static, can be controlled to some extent during the mine design, the environmental and economic factors dynamically change and therefore can only be controlled through a flexible mine ventilation system.With an average temperature gradient of 20–25°C/km, the virgin rock temperature at 2,000 m can reach 45–60°C. Conventional cooling at such depths could lead to exorbitantly high costs. In-mine geothermal heat pumps can considerably reduce the cost of cooling through energy communication with the centralized absorption chillers, which service the mine from the surface.It is shown that in-mine heat pump systems can be a viable option for reducing operating expenses and providing some degree of flexibility to cope with fluctuating energy costs. The price of Natural gas and electrify are the most important variables for optimizing the level of interaction between the surface and inmine cooling systems. Deep mine waters can be used to carry a portion of the mine heat to the surface, where the heat from mine can be used as a supplementary energy source for absorption chillers. As an extra benefit, the heat output of the chillers can be used for district heating and or greenhouse growing.The case of cooling deep levels of deep mines in Sudbury Canada (e.g. Creighton Mine) has been discussed. It is shown that an initial 1MW in-mine geothermal heat pump system can save significantly on the cost of cooling. Such a demonstration project will allow R&D on viability of larger similar systems to be incrementally added in the future.INTRODUCTIONThe amount of heat generated in deep and ultra-deep mines depend primarily on the regional temperature gradient and the thermal conductivity of mine rocks. The conductive heat flow is quantifiable and can be minimized or optimized in the process of mine design. Another important heat source can be related to underground equipment such as diesel machinery which often have low efficiencies (approximately 25–35%). This heat source can be controlled and reduced though improving efficiencies or using electrical equipment, which offer a much better efficiency (approximately 80–90%). Mine waters can also be a significant heat source (convectively bringing large amounts of heat into the mine workings)."

Jan 1, 2019

By K. E. Waters, M. Mirnezami, R. Gauvin, A. Jordens, K. W. Malas

"There is currently very little information on the physico-chemical properties of rare earth elementbearing minerals, or on their processing. With the increasing demand for rare earths, this is something that needs to be addressed. This paper introduces some surface chemistry analysis of fergusonite (YNbO4), and the bubble-particle attachment. Zeta potential measurements indicate adsorption of sodium oleate and, to a lesser degree, potassium amyl xanthate onto the surface, and an increase in attachment to an air bubble is observed at pH 4.5 and 6.5. At a pH of 10.5, no attachment is observed, whether in the presence of the reagents or not. This analysis, although initial, will be used to initiate flotation tests, in order to facilitate the selective recovery of fergusonite. INTRODUCTIONRare earth elements (REE) are increasingly in demand, due to their prevalence in both renewable energy devices and high-end electronics. An article in the New Scientist highlighted the importance of a number of REE, many of which most people are be unlikely to have heard mentioned (Crow, 2011). From batteries (lanthanum and cerium) to magnets (dysprosium and neodymium) and lighting (yttrium), the REE are crucial to the advancement of technology and energy saving devices. For example, neodymium is finding most use in the high end magnets that keep the motors turning that power wind turbines and electric cars. In the case of yttrium, the demand outstripped the supply in 2010, emphasising the need to develop deposits containing this and other REE (Crow, 2011). The impact of our dependency on REE has become even more apparent with the reduction in exports by China, which currently controls 97 % of the world’s rare earth production (Pitts, 2011).With the increasing demand for rare earth elements (REE), there is a drive to exploit the known resources around the world. However, the physical beneficiation of the rare earth element bearing minerals is a subject which will require a great deal of investigation to fill the knowledge gaps surrounding these developing rare earth projects. There are numerous articles on REE mineralogy as well as the hydrometallurgical processing of REE concentrates (Alex, Suri, & Gupta, 1998; Peter Gromet & Silver, 1983; Ring et al., 1993; Schnetzler & Philpotts, 1970; Uda, 2000), however a common feature amongst these resources is the lack of detailed descriptions of the physical beneficiation processes required to concentrate REE-bearing minerals. There is work being conducted into reagents and methods for use in recovering some rare earths from their associated ores (Bulatovic, 2010; Ni, Parrent, Cao, & Liu, 2011), but much more in-depth research is required."

Jan 1, 2012

By Walter E. Montgomery

ACCIDENT-PREVENTION work in years gone by has been carried on by many mine managers as a philanthropic movement, but in recent years they have come to realise that Safety is good business and pays tangible dividends. Let us begin with the word itself. We are told that an accident is "any-thing occurring unexpectedly, undesignedly, or without known or assign-able cause'. It is further explained that it is any 'unpleasant or unfortunate occurrence involving injury, loss, suffering, or death", and, finally, "any unintentional or non-essential circumstance". We admit that accidents are unfortunate, unpleasant, unintentional, and they generally happen undesignedly and to a great degree unexpectedly, but to say that they happen "without known or assignable cause" leads us to believe that the word 'accident' is often misused. Would it not be more correct to say that a man suffered a "personal injury"? The word 'accident' in its proper sense implies something over which no one has any control, but when the majority of all so-called accidents are analysed we arrive at the incontestible fact that some act or action, previous or present, was the underlying cause. As long ago as the year 1556 this fact was mentioned by Georgius Agricola, who, in writing a paper on metallurgy, aptly stated, "It remains for me to speak on the ailments and accidents of mines, and of the methods by which they can guard against these, for we should always devote more care to maintaining our health, that we may freely perform the functions of our body, than to making profits". Farther on, Agricola relates in more detail, "Sometimes workmen slipping from ladders into the shafts break their arms, legs, or necks, or fall into the sumps and are drowned; often, indeed, the negligence of the foreman is to blame, for it is his special work both to fix the ladder so firmly to the timbers that they cannot break away, and to cover so securely with planks the sumps at the bottom of the shafts, that the planks cannot be moved nor the men fall into the water; wherefore the foreman must carefully execute his own work. Moreover, he must not set the entrance of the shaft-house toward the north wind, lest in winter the ladders freeze with cold, for when this happens the man's hands become stiff and slipping with cold, and cannot perform their office of holding. The men, too, must be careful that, even if none of these things happen, they do not fall from their own carelessness'.

Jan 1, 1938

By S. Bozorgi, K. Anders

"The automotive applications of heat treatable AlCu cast alloys are designed for performance at high temperature, which can be improved using specially alloying element as well as different heat treatment. In this research work an effect of alloying element such as Cu, Ni and heat treatment on microstructures and mechanical properties of AlCu alloy were investigated using optical microscope (LIMI), scanning electronic microscope (SEM) equipped with energy dispersive X-ray detection (EDS), Differential scanning calorimetry (DSC) and mechanical testing. It was found that during solidification most of the elements Cu, Mg and Ni segregated at the grain boundaries in the form of Al2CuMg or Al7Cu4Ni and a very small part of Cu and Ni element dissolved in the FCC-Al matrix. The latter is not completely reclaimable for strengthening mechanisms in FCC-Al matrix in its as-cast state. The results of mechanical test show that yield strength and ultimate tensile strength increases after heat treatment significantly compared with the as-cast state. Furthermore the mechanical properties at elevates temperature (240°C) is higher with higher Cu+Ni+Si containing alloys compared with the less Cu+Ni+Si containing alloy.INTRODUCTION Due to the high strength-to-weight ratio, high strength and ductility at room- and elevated temperature, AlCuSi cast alloys are widely applied in the automotive industries specially for producing cylinder head and engine block, where modified alloys with enhanced metallurgical properties are always needed to satisfy the ever increasing demands for the applications. The AlCu based cast alloys can be strengthened by age hardening. The precipitation processes from which this hardening is derived can be attributed to the presence of selected trace element additions or micro alloying, which can change the process or kinetics of precipitation in age hardenable AlCu cast alloys (Polmear, 1998; Morris, 1991). Furthermore their strength is mainly controlled by the aging process through the precipitation and growth of very fine precipitates of the ?'-phase (a semi-coherent, metastable form of the equilibrium Al2Cu phase) from the Al and Cu Guinier-Preston (GP) zones. Several studies have shown that solute clustering occurs prior to the precipitation of GP zones, and this modifies both the nature and kinetics of the precipitation process. The typical size of GP zones is in the order of tens of nanometers, and the chemical composition of these precipitates is not easily measured, even with a typically analytical electron microscope (Polmear, 1989)."

Jan 1, 2018

By E. H. Henderson

MR. R. V. NEILY stated that he had at one time operated at Goldenville. The practice and results are much the same now as in the olden days. Inside plates were then found to be a source of trouble and had been removed. At the Libbey mine, Queen's county, the sulphides carried considerable gold, and $45.00 to $60.00 per ton had been recovered from the concentrates by roasting and chlorinating. Later, concentrates were treated with bromocyanide. Following that practice, a cyanide leaching plant was installed, which did not require concentration of the tailings. Cyanidation brought a recovery of around 95 per cent, with but $300 worth of plant. In Nova Scotia, the ore of each locality presents an individual problem of its own as to treatment required. Ma. W. B. Timm stated that, in the majority of Nova Scotia gold ores, more than 75 per cent of the gold content is free-milling and, naturally, stamps are most efficient for collecting and amalgamating this gold. In Ontario and the West, they had got away from stamps, and perhaps the main reason was that the supply of battery-men, who came from Nova Scotia, had died off. Ball-mills had been installed, which required smaller space and handled large tonnage, even though, as far as amalgamation goes, the stamps were probably more efficient. If concentration is to be done, ore from stamps is usually in better shape for recovery in passing over the tables, as there is no slime. With the ball-mill, flotation is necessary. The better practice, undoubtedly, is to take out what gold is possible before it is all smashed up, as in the ball-mill, though recent developments in the ball-mill make it possible to trap and take coarse gold directly from the mill. In this way, cyanidation is speeded-up, due to saving of the time the coarse gold would take before going into solution. PROFESSOR A. E. FLYNN found it unusual in these days to read anything in favour of the stamp mill, and thanked Mr. Henderson for the excellent paper in which he upholds the stamps and backs his opinion with facts from actual operations. For the typical Nova Scotia ore, containing coarse gold, stamps are un¬excelled. It used to be said that the virtue of stamps is that they brighten the gold for amalgamation. Although this saying is almost classical, it is not true, for gold is never brighter than in the native, untouched state. Any hammering that gold gets makes it more difficult to amalgamate.

Jan 1, 1935

By Chris D. Veldhoen

If you ask most diamond drillers if they have ever encountered methane gas, the answer would probably be yes. This paper explores a serious methane gas explosion that the author experienced while diamond drilling at a northerly Ontario mine. It is hoped that by documenting this event, people may be alerted to the hidden danger posed by confined methane in underground workings. Methane gas tends to be a problem the deeper you get in any Canadian gold mine. Common procedure when encountering methane is to take readings at the collar of the hole and at different lengths from the source. Monitoring continues until the readings drop below 0.25 ppm. Methane is a tasteless odorless gas that is usually locked up in the seams of the rock or is a product of decaying organic material. Occasionally, the gas is released abruptly over a short period of time. Sometimes the gas can continue to vent for months or even years. In small concentrations, methane is relatively safe. In concentrations under 0.25 ppm methane gas is considered safe to work around. Concentrations over 0.25 ppm can become dangerous. During the summer of 2001, Chris Veldhoen was drilling at a gold mine in Ontario. There were three electric hydraulic diamond drills on the 39 meter level, approximately 5200 feet deep. Two Longyear LM 55 drills were about 40 feet apart and another LM 75 was about 2000 feet away. The two LM 55?s were set up to drill holes no deeper than 350 meters. All three drills had been set up on the same spot for more than a month. None of the three drills had ever encountered methane gas in the entire time they had been drilling on the level. On the day shift of July 13 2001, the driller on Chris? cross shift hit a small pocket of gas. He tested the hole and got a reading above 0.25 ppm. He proceeded to rope off the area with a ?DO NOT ENTER - METHANE GAS? sign and a rope denying access beyond the sign. On Saturday, July 14, Chris was instructed to install a Margo plug in the hole that was emitting methane gas. Methane is usually odorless, but occasionally when encountered underground, is accompanied by a rotten egg smell. As he walked to the drill, he could not smell methane gas. He proceeded to test the hole and got a reading of 0.22 ppm methane. This number was in the acceptable range for drilling, but he plugged the hole anyway.

May 1, 2004

By J. D. Templeton

A petroleum well that is not in use because it has ceased to produce oil/gas economically and dry holes are referred to as abandoned wells. Once a well is abandoned it is plugged with cement and can take anywhere from two days up to a week to cure depending on the number of plugs in the well. Since plugging a well costs capital, most wells are abandoned at the lowest possible cost and with the minimum obligations set by regulation agencies. These wells can present an enduring liability to petroleum companies. However, the depth and abundance of abandoned petroleum wells makes them an economically attractive source of geothermal energy. Geothermal energy harvested from an oil/gas well is a renewable energy source as long as it is extracted in a sustainable manner. The energy can be used to generate electricity, used directly for heating, incorporated into a water desalination process, or used by a heat pump for heating/cooling applications. In this paper we examine the possibility of extracting geothermal energy from abandoned oil/gas wells by studying the heat transfer in underground geothermal heat exchangers installed in these wells. The design configurations for the geothermal heat exchangers embedded inside a petroleum borehole can be a u-tube design or a shell and tube design (i.e. double pipe). Using in-situ gathered information from some representative petroleum boreholes, the effects of key parameters such as geothermal gradient, ground temperature values, and the flow inside of the tubes are evaluated. In order to provide a constant power production the inlet temperature can be adjusted to keep the difference between outlet and inlet temperatures equivalent. Higher differences between inflow and outflow temperatures will result in a less sustainable load put on the in-situ geothermal energy. Adding insulation to certain sections of the designs can minimize the transfer of thermal energy from the fluid to the surroundings. Insulation can also limit the thermal loss between the inflow and outflow tubes in the shell and tube design. Minimizing the energy loss of these designs leads to an increase in the outlet temperature, meaning a higher grade of heat. The sustainability of long term geothermal heat extraction is a balance between the rate at which geothermal energy is extracted and the rate at which the ground formation can replace this heat. Higher outlet temperatures can lead to a larger amount of power generation, and a higher coefficient of performance for heat pump applications.

Aug 1, 2013

By P. E. Mather, M. J. M. Krane

Uncertainty quantification is a means of articulating the reliability of model estimations. Models of copper pyrometallurgical processes have been published for decades but discussion of their reliability has typically been terse and qualitative, mitigating understanding of their exact applicability to industrial situations. This presentation shows basic uncertainty propagation and Bayesian model calibration, two powerful uncertainty quantification tools, applied to a reduced order model of copper fire/anode refining. The implications of the uncertainty quantification analyses on the applicability of the model results to industrial practice are then discussed. Finally, other possible applications of uncertainty quantification to copper extractive metallurgy are explored. INTRODUCTION Modern copper production operations, including mining operations through wire drawing factories, are ubiquitously heavily instrumented. Most mine-sites and smelters have large repositories of historical data. That said, much of this data is not exploited to its maximum effect. This proceeding provides examples of using uncertainty quantification (UQ) to maximize the informational yield of the data collected from a fire-refining operation. Anode/Fire Refining is the final pyrometallurgical step in the production of copper anodes; it is an essential and universally employed processing step at smelters (Schlesinger, King, Sole, & Davenport, 2011). Much like the smelting and converting furnaces further up the process stream, anode furnaces are difficult to instrument due to their high temperature and the corrosive and/or caking quality of their offgas. This makes continuous and accurate measurement of the streams leaving the unit operation, e.g. liquid copper, slag, and offgas very difficult. As an example, offgas flowmeters, while providing continuous draft values, could miss the actual draft value by tens of percent due to caking or corrosion. UQ methods account for the uncertainty in process measurements and parameter values; they use a process model with measurements of performance indices to provide better and better estimations of process performance. This proceeding will first introduce a surrogate model for copper fire refining, made from a 1D, transient, reacting flow model of the process presented elsewhere in these proceedings (Mather & Krane, 2019). Discussion of the data used to make the surrogate model, as well as the creation of the surrogate model, will be included. Then, a Monte Carlo simulation will be performed, showing the expected soot production rate based on the surrogate model and assumptions about the uncertainty in the model’s parameters. Finally, the surrogate model parameters will be calibrated in a Bayesian way; this will tell what the actual uncertainty in the parameters are, given a set of observed industrial data and prior assumptions of the observations’ and parameters’ uncertainty.

Jan 1, 2019

By A. Mcdonald

"An X-Met Analyzer was purchased from Outokumpu in late 1983for use in the Hudson Bay Mining and Smelting smelter. Its first use was in the fuming plant to give zinc assays of each charge of slag tapped from the fuming furnaces. This quickly told the operators exactly when each charge had reached its economic tap-out point, and gave supervision a fool-proof method of identifying good operation. These and other factors led to major improvements in coal utilization in the fumers and to major increases in zinc oxide production. A second unit was later purchased for the reverberatory furnace to give silica and iron assays of the slag, and these were used to make adjustments in the feed composition to maintain the desired SiO2:Fe ratio in the slag. Since purchasing the units for the furnace, the oil consumption and copper content of the slag have dropped significantly. IntroductionSmelters have lagged far behind concentrators in process control by mean s of rapid product analysis. The on-stream X-ray analyzer was developed about seventeen years ago, and soon concentrators around the world were getting assays of the incoming ore, .concentrates and tailings every fifteen minutes, and using these to control reagent additions and other process variables. Almost always, the concentrate grade and recovery improved.In smelters, product streams are solids or molten materials, not the more easily handled slurries, and until seven years ago no inexpensive equipment was available to provide rapid analysis of this type of material. In approximately 1980, several companies developed instruments based on irradiating solid samples with low-intensity gamma rays from radio-isotope sources, and measuring the secondary X-rays emitted from different elements in the sample to provide an analysis of the elements desired.The smelter staff had a close look at what was needed and listed the following points as being critical:1. ability to provide Zn assays of a sample of slag within 15 minutes of taking it, in order to achieve optimum fuming times (zinc fuming , being a batch process, had the greatest potential benefit from rapid slag analysis);2. ability to give Cu and Fe assays on the slag, and on other smelter products, such as matte and converter slag;3. ability to give Si02 assays since the SiO2 content of the slag has a strong effect on fuming rate; and4. ability to stand up to an industrial atmosphere such as exists in the fuming plant."

Jan 1, 1987

By C. R. Edwards

"Since the first commercial extraction of uranium in the early 1940s, the range of feasible process alternatives has greatly increased. This paper reviews process options to reduce extraction costs, improve efficiencies, effect safer operations, and lessen environmental impacts. Equipment and processes used in the past, in use now, and that could be considered for future use are described.BackgroundTwo billion years ago life on earth consisted solely of single celled creatures of the simplest design (Gould 1989). Incredible as it may seem, uranium fission reactors were operating then also. In what is now western Africa, a series of natural reactors were fueled by rich uranium deposits in contact with underground rivers. Water from the rivers provided the moderator necessary to sustain the nuclear fission chain reaction. These primordial reactors ran down after about 600 000 years (Ontario Hydro 1989).Because it is ubiquitous in the earth's crust, humans have always been in contact with uranium. Mining of uranium, albeit not intentional, is ancient ; uranium minerals were embedded in ore veins mined for metals such as silver and copper.Uranium was discovered in 1789 in Berlin by an apothecary, Martin Heinrich Klaproth, who named the element after the recently discovered planet Uranus. The metallic element uranium, as opposed to its compounds, was extracted in 1841 by the French chemist Eugene-Melchior Peligot. The atomic mass of uranium was calculated to be 120, but the Russian genius Dmitri Ivanovich Mendeleev (famous and welcome everywhere except in Russia, where his liberal politics were detested by the Tsar), found this did not fit into his periodic table, and submitted a value of 240. Mendeleev was close; the exact atomic mass is 238.029.Henri Becquerel's detection of the radioactivity of uranium in 1896excited scientific study of the metal, but virtually no practical use was found for uranium outside of a minimal consumption as a colouring agent for glass and ceramics. Scientific interest intensified in the 19305. In 1933 Leo Szilard patented the concept of the nuclear chain reaction. While walking to work on a fine fall London morning and mulling over the problem of how to release atomic energy, he was stopped by a red light. He stood in thought and conceived the notion of the neutron-activated chain reaction before the light turned green. The patent was filed in 1934, and Szilard assigned it to the British Admiralty in order to keep it secret, in an honourable but ultimately futile effort to prevent the misuse of science (Bronowski 1973)."

Jan 1, 1992

By Stuart Elliot

Brownfield project portfolios are notoriously hard to manage. Day to day there is a constant stream of changes and challenges within projects and across the whole program. When the budget year is over, we?re often left wondering: did the facilities get what they really needed? Did we get value for the capital that was spent? Did we get all the project control and process improvement that we paid for? Great work has been done over the years by the Project Management Institute, Construction Industry Institute and Independent Project Analysis to identify what leads to project success, develop project delivery systems and equip project leaders to perform better. But is attention to individual projects all we need when the job is to deliver a portfolio of many projects? Let?s work with an analogy for a moment, and say a project is like a car, and a project manager the driver. Why can?t all the projects in the portfolio get home in time for dinner? The answer, of course, is that the commute home is about traffic, not just about cars. The road, the signals and the actions of other drivers affect us in our individual cars. Optimizing traffic flow is not about managing individual cars, it is about creating the conditions that allow all traffic to move as smoothly as possible. When we?re stuck in traffic, it doesn?t really matter that we are skilled drivers who know our exact location and our engine?s vital signs. Success with a brownfield portfolio requires more than the equivalent of driver training and a good GPS in every vehicle. Managing the annual budget requires more than tight management of each project. This is not a suggestion to abandon project management in the brownfield multi-projects world; the idea is to find and apply the right tools for delivering a portfolio. Remember, we want confidence in 3 areas: 1. that the facility is getting what it really needs, when it needs it 2. that we are getting value for money invested in facility modifications and improvements, and 3. that our controls are adding value by guiding our improvement What are those portfolio tools? The job they have to do is distinct from project-level thinking: ? Create a clear and balanced business pull for project ideas ? Maintain a respectable plan for fiscal, resource and business control ? Organize the work into a steady flow ? Manage the nature and timing of value-driven project substitutions and priority changes ? Focus on overall business value added and best use of resources ? Repurpose the projects organization into being the way the facility gets improved

Nov 1, 2011

By Toshiharu Teranishi

When we apply the Au nanoparticle superlattices to the future nanooptical and nanoelectronic devices, the control of not only the particle size but also the interparticle spacing and symmetry of superlattice are the essential problems to be overcome. First, we developed a novel synthetic procedure to precisely control the particle size of alkanethiol-protected Au nanoparticles in the range from 1.5 to 9.7 nm by the heat-treatment of the small Au nanoparticles in the solid state. Absorption and nonlinear optical properties of alkanethiol-protected Au nanoparticle superlattices were then elucidated. On the other hand, the hexagonal close-packed (hcp) 2D superlattices of small Au nanoparticles with the interparticle spacings from 1.9 to 3.6 nm were successfully prepared by using newly-synthesized ligand for single electron tunneling devices. Finally, various symmetric superlattices, such as chain (2-fold), quasi-honeycomb (3-fold), square (4-fold), etc., of Au nanoparticles could be produced by making use of interligand interactions or some templates.

Oct 1, 2003

By Peter L. Sheehan, David A. Fawcett, Dennis C. Martin

"Smoky River Coal Limited has successfully completed a major program involving the pattern rock anchoring of a high, steeply dipping footwall slope. The slope dips at approximately 65 to 70 degrees to the north, is benched for the upper 200 feet, is supported with rock anchors for another 240feet, and is unsupported at the pit bottom. In addition to the height and steepness, several structural features including shears, rolls and stratigraphic pinch- outs complicate footwall stability.This paper presents an overview of the project with descriptions of the engineering geology and footwall design, anchor installation, instrumentation and monitoring and a cost summary.IntroductionSmoky River Coal's mines are located in the foothills of the Rocky Mountains near Grande Cache, Alberta, approximately 200 miles west of Edmonton. The Smoky River coal leases were initially developed in the late 1960s and, except for minor shutdowns, have been in continuous operation since 1969 producing a low volatile metallurgical coal, mainly for the export market. Initial coal production was from underground mines; sur face mining started in 1971, and a large surface mine, No.9 Mine, was opened in 1974. Since that time, a number of open pits have been mined within the No.9 Mine area. Surface mining is by conventional shovel-truck method s with the use of a backhoe for mining the narrow pit bottoms.Coal recovery is mainly from the No.4 seam, which has a typical unstructured thickness of 20 feet. The most attractive opportunities for open-pit mining exist in areas of over thickening of the coal seam in the hinge zones of synclines and anticlines and in dip-slope situations. The mining of the more structurally complex pits and steeply-dipping footwall slopes requires that consideration be given to footwall stability."

Jan 1, 1988

By Mohamed Ourriban, Stéphanie Somot, Éric Proulx, Jean-Sébastien Marois, Marjolaine Drouin, Paul Blatter, Ahmed Bouajila, Claude Gagnon

"The mining industry has to face increasing restrictions concerning the use of fresh water in Québec and throughout the world. Increasing recirculated water usage could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have a negative impact on mineral processing operations, thereby limiting the incentive for sustainable development initiatives. As a first step into selecting and testing remediation strategies, one of which being blending local waters, a mapping of process water quality (inorganic and organic fractions) allowed to locate zones in an industrial case study where fresh water is introduced into the circuit and to detect dissolution and precipitation zones. A complementary hydro-geochemical modeling study on water blends was also performed showing encouraging results towards the objectives of the project.INTRODUCTION The industry has to face increasing restrictions on the use of fresh water in Québec (Quebec Government, 2009) and throughout the world (Brown, 2003; UNESCO, 2006). The cost for the use of fresh water and for water management is highly variable and case-dependent (from 0.2 to up to 7 million dollars/year according to available private estimations, excluding the capital expenditure). It may be, or may become, significant for any plant; thus, risk assessment is of concern here. Using recirculated water could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have some positive and negative impacts on mineral processing operations (Janssen, 2003; Johnson, 2003; Rao and Finch, 1989). Negative impacts could limit the incentive for sustainable development initiatives. Water management strategies at mineral processing sites are supported both by a strategic plan and a water management plan. The strategic plan includes legal aspects, investment costs, potential benefits and various risk levels (Corder and Moran, 2006; Côte et al, 2006; Evans et al., 2006; MacIntosh and Merritt, 2003; McLellan et al., 2008; Merritt and MacIntosh, 2006; Robinson and Keddie, 2006; van Beers et al., 2007a; van Beers et al., 2007b; van Berkel, 2007). In practice, the strategic plan evaluates technical possibilities and costs of various scenarios, such as for example: bringing fresh water to the plant or recirculating waters, or using blends of both. Two important factors to consider in order to enhance the future production efficiency and to minimise risks are: the durability and the stability of the resource, both from quality and quantity points of view."

Jan 1, 2012

By Michael Samis

Conventional project valuation techniques, such as discounted cash flow (DCF) method, are more frequently being criticised for the manner in which they consider the interacting effects of uncertainty and project structure (including management flexibility) on project value. Modern asset pricing (MAP; often called ?real options valuation? when applied to the analysis of flexibility) is a more general valuation framework that corrects many of the shortcomings of common valuation methods. Previous mining applications of MAP have tended to treat the ore deposit as a homogenous entity. While useful for demonstration purposes, this is inadequate for practical application in industry. This paper presents a MAP valuation example that allows for the heterogeneous nature of an ore deposit. It shows that deposit structure may increase the complexity of the mine planner?s decision so that results of a standard DCF analysis, or a simple MAP analysis that ignores the details of deposit structure, are misleading. In the example, a management is considering the development of an adjacent low-grade zone while mining operations in a high-grade zone are ongoing. If the low-grade zone is developed before high-grade reserves are exhausted, the proposed development will include both low-grade zone development and a capacity expansion to handle additional low-grade reserve production. If development of these reserves is delayed until the high-grade reserves are depleted, then the low-grade reserves can be developed without a capacity expansion. A typical DCF analysis would reduce the management?s decision problem to three alternatives: 1) continue mining only in the highgrade reserves, 2) immediately develop the low-grade reserves and expand capacity, and 3) delay low-grade zone development until the high-grade reserves are exhausted. The model presented here allows the management to reconsider the development and capacity expansion decision on a discrete half-year basis. It delineates price regions, for given levels of high-grade zone reserves, in which it is optimal to develop the low-grade zone, defer low-grade zone development and abandon the mine irrevocably. The model presented here extends the ability of mine planners to describe actual project structure while using the MAP valuation framework that is already noted for its capacity to combine project uncertainty and risk insights with a dynamic project description.

May 1, 2001