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By K. E. Waters, E. R. L. Espiritu, G. R. da Silva

"Rare earth (RE) elements are essential components of emerging green technologies. The increase in demand for these applications have driven the search and development of new rare earth deposits such as the Niobec project in Quebec, Canada. This deposit consists primarily of dolomite with significant amount of RE minerals bastnäsite and monazite, the primary sources of RE elements. Due to the minerals’ fine liberation sizes, flotation is commonly used as a concentration method. To develop an efficient process, the electrokinetic properties of the minerals must be understood. In this study, the surface properties of bastnäsite, monazite (RE minerals) and dolomite (a common gangue mineral) were investigated by zeta potential measurements. These measurements are affected by various ions present in solution; for bastnäsite, monazite and dolomite, some of these ions are H+, OH-, PO43- and CO32-. Dolomite, being a sparingly soluble mineral and a primary component of the ore, may be the greatest contributor of these ions in solution in the form of CO32- ions. Thus, different sources of CO32- ions (from dolomite dissolution and from Na2CO3) were investigated. The research work aims at elucidating how these reagents may influence the minerals’ surfaces. The results have shown that dolomite supernatant and sodium carbonate greatly affect the electrokinetic properties of each minerals. The addition of dolomite supernatant have resulted to relatively similar zeta potential of the minerals; while, sodium carbonate have affected them differently. These observations could be useful in efficient flotation of bastnäsite and/or monazite from bastnäsite-monazite-dolomite system.INTRODUCTIONThe increase in the demand for rare earth (RE) elements has driven the search and development of new deposits. Out of 53 rare earth projects in the world, 19 can be found in Canada (Hatch, 2015). These include the Niobec project of Magris Resources Company in Quebec. This deposit contains a significant amount of rare earth minerals (such as bastnäsite and monazite), with carbonates (such as dolomite) as the primary gangue minerals."

Jan 1, 2016

By Kazuhide Nakaniwa

In this research, we devised a measurement method using total stations (TSs) which have ?the Baum? which is a concentric circle reticle, as substitute for crosshairs. The Baum owes its name to the similarity between the concentric circles and trees (Baum in German). By setting one circle on both of edges of cylinders, operators can set their sights on points on the center line of the cylinders, and also can measure positional coordinates of the points. Also, by measuring two different points on the center line, operators can measure the position and tilt of the axes of the cylinders. Furthermore, we developed a pile driving navigation system. Foundation piles are used for various structures, and their forms are generally cylindrical. Especially, although it is difficult to drive tilted pile foundations, their usage are expected to expand due to their high earthquake resistance. Yet, a method to accurately measure the tilts of piles has not been established. However, we proved that operators can obtain adequate accuracy to control foundation piles through the measurement experiment using this system. Using this system, the information of the pile is measured using a TS, transferred to a PDA, and displayed from the operator?s view of the piling machine.

Aug 1, 2013

By Frederick Bird

This paper is based upon a review of studies of mostly Canadian mining companies in Chile, northern Canada, Tanzania, Guatemala, Ghana, Sierra Leone, and the Democratic Republic of Congo. In spite of often well-meaning efforts most mining firms produce wealth in developing areas that largely benefit those immediately involved, sometimes neighboring communities, and often those in the governing strata. Typically mining takes place in enclaves and fosters enclave development, rather than the kind of inclusive wealth development favored by the recently UN published Inclusive Wealth Report. One way by which mining operations can foster more inclusive wealth development is to adopt much broader approaches towards the construction of the various physical and social infrastructures ? roads, water, electricity, health services, schools, security ? required for their own operations by collaborating with diverse regional, provincial, and/or national agencies and businesses to develop these infrastructures for larger populations and areas beyond the immediate sites where they are operating. Established mining firms can also foster more inclusive wealth development by establishing more formal, collaborative relationships with artisanal miners.

Aug 1, 2013

By Helge B. Wurst, Michael P. Cipold, Jan F. Bachmann, Claus C. Bachmann

"In washability, the objective is to establish the set of maximum possible separation performance criteria for a given mineral feed. The method of choice for this has been the conventional sink-float analysis. Time, cost and safety aspects of the sink-float method have prompted the search for a new approach for establishing separation performance criteria, especially as performance levels of separator plants can be maximized if reliable information based on an analysis of washability in conjunction with particle size distribution, elemental constituency becomes readily available. The new method to establish washability and associated performance information utilizes at least two measurement technologies concurrently: single energy x-ray transmission and image processing. For porous or very inhomogeneous materials the results can be refined further by using dual energy x-ray transmission and image processing. The value of the collected data increases considerably if the washability data were additionally available in time to be considered in the control of the process plant. The incorporation of an automated washability monitor gives near real-time data that would impinge positively on the profitability of the plant operation. The method was extensively tested with a range of sample with different densities, varying from 1 g/cm³ (coal) to 5 g/cm³ (iron ore).INTRODUCTIONWashability of minerals like coal and iron ore is expressed by a curve or graph showing the results of a series of float-and-sink tests. Several of these curves are drawn to illustrate different conditions or variables, usually on the same axes, thus presenting the information on one sheet of paper. Washability curves are essential not only for the design but also for the operation of preparation plants.In determining the washability analysis, particle density is the underlying feature of all washability curves. Conventionally, the particles are separated into density fractions by immersing them in fluids of a predetermined density followed by skimming of those particles that stay afloat. The particles remaining afloat thus have a density lower than that of the fluid they were subjected to. The particles that remained at the bottom of the fluid container thus had a higher density higher than that of the fluid. By progressively increasing, for example, the density of the fluid and immersing the remaining particles so as to be able to skim the next density fraction, the particles would be fractionated into density groups. The liquids used range from aqueous solutions to organic liquids to suspensions. Unfortunately the liquids used for this separation process are often toxic and expensive. It stands to reason that a new method of determining washability is sought."

Jan 1, 2016

By M. Pötsch, A. Kluckner, P. Söllner, W. Schubert

"The in situ block size is a key parameter in the geomechanical characterization of rock masses. It describes the fracturing of the rock mass and thus is a measure for the degradation of the rock mass strength. Several classification systems use the in situ block size. For instance, the Geological Strength Index (GSI) requires the “blockiness” and joint surface condition factor as key input parameters. The “blockiness” has recently been related to the in situ block volume (Cai et al., 2004). Due to the limited information about the internals of a rock mass, it is not possible to determine the in situ block size directly. Currently, the in situ block size is determined by calculations using oversimplified models, vague estimations or, due to the lack of relevant information, it is neglected. As remote measurement systems have become available for rock mass characterization, a more comprehensive record of discontinuities can take place. Measurements can be performed on exposed rock outcrops and in particular on tunnel faces and walls, delivering the location, orientation, spacing and persistence of discontinuities at an arbitrary number and locations. An estimation of the in situ block size at the same level of sophistication is still not available. This paper aims at examining the relationship between visible and measureable information at the rock surface, and the in situ block size. Three-dimensional block model simulations were performed using the block model engine of the distinct element code 3DEC. Initial investigations focussed on the minimally required observation area in order to obtain reliable block size distributions. Based on a representative volume element, a reference distribution of the block area at the observation area for a specific discontinuity system was determined. Subsequently, the size of the observation area was decreased stepwise and each new distribution was compared to the reference distribution. For all analyzed systems, it turned out that the mean block area must be smaller than 1% of the observation area to achieve a reliable block size distribution. Further simulations focussed on discontinuity systems with three non-persistent sets. The results were compared to the formula proposed by Cai et al. (2004). A transformation factor T was introduced which replaces the persistence terms in Cai et al.’s proposed formula. The factor describes the correlation between block volumes generated by persistent and corresponding non-persistent discontinuity sets. The simulations included the variation of the discontinuity set spacing, persistence, and orientation. The mean and additionally the 25%-, 50%- and 75%-quantiles of the block size distribution were analyzed. Examining all values for the transformation factor the distribution can be described by a power function with a negative exponent. The function depends on the persistence only. Finally, the results of random simulations were compared to the analytical formula using the transformation factor. The predicted mean and selected quantiles show a good agreement with the simulation results. It gives a comprehensive picture about the block size distribution in discontinuity systems with three non-persistent sets."

Jan 1, 2015

By P. Schmidt, M. Hopf

Water-cooled parts of submerged arc furnaces are potentially dangerous, especially if molten matte or slag contacts the water. Explosion hazards and metal run-outs generate high costs for production loss and repairs - not mentioning the possible loss of human life. This paper reports about practical results of wear measurement on intensive water-cooled tap-holes and spray-cooled side walls. On the one hand an embedding technology has been developed, that is used e.g. in water-cooled copper tap blocks or copper side wall coolers. Second the application of the sensor installation on the inner side of a water-cooled steel shell will be discussed. The fibre-optic sensor is fed through a specially arranged piping system and measures numerous temperatures over its entire length. By using the thermal conductivity of the installed refractory materials the lining thickness is calculated. The practical installation of the sensors will be discussed and the results of the wear measurement will be compared to the theoretical FEM calculations. The highly sensitive and accurate temperature measurement, as well as the recalculation of the impact of differences in the cooling water temperature, allows the exact determination of the remaining lining thickness. The discussed technologies offer efficient and safe monitoring of tap-holes, side walls and other endangered parts of pyro-metallurgical smelters.

Jan 1, 2015

By D. Tetsuka, H. Okamoto

The amount of impurities to be processed in a copper smelting process has increased for recent years because of an increase in the electronic scrap amount. It has been found that Sb and Ni effect on the operation of our copper electrorefining process. It is found that the current efficiency of the copper electrorefining tended to be decreased as the Ni concentration in the electrolyte increased. The passivation of the process seemed to be more related to SO4 concentration in the electrolyte rather than the Ni concentration in it. The current efficiency decreased when the Sb content in the anode was high. A high Sb content in the anode caused easy passivation by forming a gel-like film in the slime layer. We have developed a method to for see the anode passivation in a short time while generating a slime layer. We confirmed the tendency of passivation through the experiment of changing Pb content in anode. Passivation was easily occur with an increase in Pb content in the anode. The amount of slime increased as the Pb content in the anode increased. This suggests that passivation was facilitated because liquid diffusion near the anode was inhibited. INTRODUCTION The amount of impurities to be processed in copper smelting has been growing in recent years because the amount of electronic scrap has increased. Figure 1 shows that the contents of Sb and Ni in copper anodes have increased since 2007.High Sb and Ni contents in the copper anode decreased the current efficiency of the process and made the quality of copper cathode poor because of the anode passivation and the formation of floating slime in the electrolyte during electrorefining. If these influences of impurities are suppressed, it would be possible to make copper electro-refining current density higher and to process much amount of electronic scrap. We examined the components of our copper electro-refining process like anode composition, slime properties and electrolyte composition, and investigated the mechanism by which Sb and Ni affect passivation and current efficiency. When examining the influence of Ni, we noticed that the SO4 important. The effect of SO42 – was also discussed

Jan 1, 2019

By D. G. Tisdale, W. Curlook, J. M. Toguri

"In this study, the vapour phase reduction of titanium tetrachloride conforms to the traditional Kroll chemistry, but employs argon as an inert carrier gas and requires a higher reaction temperature of 1150°C to 1250°C. A vapour phase reaction is advantageous because titanium is the only condensed phase present, and the metal can be collected free of magnesium or magnesium chloride, in marked contrast to the titanium sponge produced by the conventional Kroll process. The yield of metallic titanium from the reaction was determined as magnesium additions ranged from 36% to 168% of the stoichiometric requirement. Yields of over 99% were obtained when an excess of magnesium was present. Although the collection efficiency was low, metallic titanium was collected at the reaction site, where all other species were present as vapours. Magnesium and chlorine concentrations in the collected titanium were less than 0.3%.IntroductionA proposed method (Curlook, 1987) for titanium production has been investigated as an alternative to the conventional Kroll process (Kroll, 1940). The advantages of the new process include a simplified means of recovering the product metal, and a potential for lower overall energy consumption and greater product purity. A higher reaction temperature for the reduction of titanium tetrachloride results in a vapour phase reaction, rather than the conventional liquid phase reaction. This is the major conceptual difference between the proposed and the established (Kroll) processes.This study focussed on optimization of the process chemistry and briefly examined the issue of product deposition and collection. The reduction of titanium tetrachloride with magnesium, to produce metallic titanium and gaseous magnesium chloride:"

Jan 1, 1997

By Jan Nemcik

Among other products steel mesh has been used successfully for many years to support strata and minimise loose material from falling into the mine opening. Installation of steel mesh has proven to be difficult to automate and many other products, such as Thin Spray-on Liners (TSL), have been proposed as a replacement. Ideally, the mechanical properties of these products should be superior to those of the steel mesh, however, most TSL trialled in mines to date have been weak and in addition have had slow cure times, as a result none of these materials can seriously compete with steel mesh. Now a new polymer product that cures in seconds and forms a stiff strata binder that surpasses the properties of steel mesh is under development at the University of Wollongong. To enable selection of a suitable polymer material for roadway skin reinforcement several numerical models were constructed to investigate the role of interface roughness and the influence of polymer stiffness on load transfer along the rock-polymer interface. Laboratory tests indicate that the shear adhesion of the rock-polymer interface can be substantial while the tensile adhesion can be much lower. The models indicate that the natural stone roughness and surface waviness plays a major role in shear adhesion while the elastic properties of polymer liner can significantly influence the polymer ability to resist fracture opening.

Oct 1, 2009

By V. S. Sastri, Elboujdaini. M.

"Economics of wear in mining industry and methods by which wear cost may be reduced will be discussed.IntroductionCanada loses more than $5 billion annually due to friction and wear (Table 1). It is estimated that about $1.3 billion, or about 25% of the losses, could be saved through better application of existing technology (Table 2). It should be noted that the costs given in Table 1 and 2 refer to 1986. The losses due to friction and wear and the savings would be much higher in 1996. Tribology combines the many branches and specialties in science and technology concerned with understanding and combatting friction and wear. Specifically, tribology is concerned with the design and manufacture of sliding and rolling bearings, piston rings, gears, cutting tools and other devices in which surfaces interact, in sliding or other relative motion. Tribology is concerned with the correct use of materials for interacting solid surfaces, with the interaction of the surfaces with the lubricants, with the chemistry, physics and use of lubricants. It is concerned with the reduction of friction and wear and the avoidance of associated failures in machinery. Similar tribological components such as bearings are used in different technologies and similar tribological problems such as abrasive wear occur in different industries. Thus, tribology is in itself a generic science and technology, concerned with the generation and dissemination of knowledge on friction, wear and lubrication, and the application of the knowledge, to a wide range of industrial products and equipment, from ploughs to space equipment, from prosthesis to engines, from washing machines to railways, from computers to power stations, from paper mills to mines. Avoidable losses due to friction and"

Jan 1, 1997

By Herbert D. Drechsler, James B. Stephenson

"AbstractThe paper identifies the major components of price change which affect the determination of the internal rate of return of a mining project. It illustrates several price indexes which may be used to measure general price increases, identifying techniques which might incorporate them into mine valuation procedures. The ""hurdle rate"" for new investment is discussed.IntroductionDECISIONS regarding the value of an orebody and whether or when to mine an orebody are based on an estimate of the cash flows which would be associated with its exploitation. These pro-forma cash flows represent cash in or out of a possible mineable deposit and include exploration and construction costs, sales revenues, operating expenses, taxes, debt borrowings, interest and debt repayment. It has long been recognized that when combining the cash flows occurring over the life of the mine, dollars received or paid out early have greater value than those received or paid out later. This time value of money has been incorporated into mine evaluation calculations through the use of present-value or discounting techniques. Another factor affecting mine valuation, inflation, is not accounted for by valuation techniques now in use. In recent years, price changes have become more volatile. In the past, price change could easily be ignored when evaluating potential mines. Today, the combination of larger investments and greater price volatility leads to great concern about the effects of price change on mine valuation."

Jan 1, 1977

By N. Erarslan, M. Ghamgosar

The size of rock fragments depends on the nature of the loading applied the strength of the minerals and the texture of the rock. Research in the literature demonstrates that there is a distinct difference in the rock fracturing process for static and cyclic loading. The tensile strength of brittle rocks is also one of the most significant parameters influencing the rock fracturing process and the propagation of micro-fractures on the crushing, blasting and cutting of rock. The Brazilian indirect tensile test, one of the methods approved by the International Society for Rock Mechanics (ISRM), has been used to determine rock fracture behaviour under different cyclic loading modes. In this study, the dimensions of Brisbane Tuff specimens have been selected according to the method outlined by the ISRM. The main aim of this study is to evaluate the effect of cyclic loading amplitude and frequency on the Fracture Process Zone (FPZ) at the micro-, meso- and macro-scales. The post-failure behaviour of the Brisbane Tuff specimens was obtained under cyclic loading with frequencies varied from 1 to 10 Hz. The amplitude was varied from 10% of Ultimate Tensile Strength (UTS) up to 80% UTS. Laboratory investigations of rock fragment size revealed that different loading frequencies and amplitudes produce different FPZ dimensions. Multivariate Analysis of Variance (MANOVA) results demonstrated that the FPZ dimension is relatively sensitive to the frequency change. Fragment size analysis showed that the FPZ is a consequence of the initiation, propagation and coalescence of micro-fractures and depends on the nature of the loading. Laboratory evidence showed that the FPZ dimension, for the cyclic tests performed on Brisbane tuff, is ranged from 0.07 to 20 mm. The achievement of this study highlights a key finding in the understanding of fracture patterns and propagation models in the FPZ under cyclic loading, which is the dominate mechanical action in the oscillator disc cutter (ODC).

Jan 1, 2015

By James S. Redpath

"AbstractThis paper is an attempt. to outline the present status of underground mining contracting in Canada, and to present certain facts concerning the writing and administration of underground mining contracts which, hopefully, may be useful to those intending to engage a mining contractor . The paper is based on the author' s experience as a contractor and also as a consulting engineer advising others in the purchase of contractors' services.HistoryIN THE early days of mining contracting in Canada, the contractor was primarily a labour contractor. He was expected to bring a good crew of men that normally followed him, and to perform certain work under his own direct supervision. The owner usually looked after all other details including financing, payrolls, withholding taxes, etc , computing and paying the contractor his profit. In the pre-World-War II years, most work was done on this basis.Over the years, the contractor was called on to supply more in the way of services, and the present-day situation evolved.Labour contracts are still used, but now the contractor is expected to carry out his own administration. Most contracts now call for the supply of special tooling required to do the work. In most cases, some, if not all, supplies are the contractor 's responsibility and , in a growing number of cases, the contractor is responsible for such items as design and surveying. The ultimate in this direction is the execution of projects on a turnkey basis. Under this system , the contractor carries the project to a stage where it is turned over fully operational to the owner."

Jan 1, 1977

By A. J. Rigby

Computer generated, actual-scale furnace models have been imported into a rendering software application to provide for impressively realistic surface features and lighting. When these models are imported into a 3D engine framework, it is possible to create content-rich virtual environments allowing for complete interactivity and could provide for a powerful tool to conceptualize refractory lining designs. This technology has been applied to illustrate the optimized design concept of an anode-refining vessel, which can be expected to be completely relined in six days and to last for 4-5 years with minimal partial relining. This technology could easily be applied to other smelter furnace, converter and refining vessel designs.

Jan 1, 2007

By Marty Hudyma

Large seismic events have been reported in mines in the Sudbury mining camp for more than 70 years. Nevertheless, no detailed record of the events has been compiled. In 2008, the Sudbury Regional Seismic Network (SRSN) research project was initiated to collect more accurate data with regard to the magnitude and locations of mining-induced seismic events in and near the mines in the Sudbury Basin. The data is used to better understand the mechanisms of the events and cause-effect relations between mining and seismic events. Through the collection of a central database of large seismic events, new insight is being be gained into why some mines are much more prone to large events than others. Fifteen low cost seismic stations have been distributed throughout the Sudbury basin. The data from each seismic station is uploaded to a central server using the internet. Data recorded on the SRSN is processed on a daily basis, and a weekly summary of blasts and events is issued to project sponsors. Seismic events smaller than local magnitude +1.0 have been identified and located. Event location accuracy is less than 2 kilometres, however, many events have been located less than 1 km from a mine. The SRSN fills a seismic monitoring gap between the in-mine microseismic monitoring systems and the earthquake monitoring system operated by the Geological Survey of Canada. Since July 2008, more than 600 mine blasts and more than 450 mining-induced seismic events have been recorded in the Sudbury basin. This paper primarily discusses the technical aspects of the design and operation of the SRSN. The SRSN is a Canadian Mining Industry Research Organisation (CAMIRO) research project, with industry sponsorship and support from FNX Mining, Itasca Canada, Vale Inco and Xstrata Nickel.

Oct 1, 2010

By Angela L. Paveley

Economic viability of base metal mining is complicated by a volatile market that can cause fluctuations in the growth and stability of the mining industry. Nickel is mined primarily for use in manufacturing industrial stainless steel and plating materials. It is essential that nickel production be sufficient to respond to current and future market demand. A Post-Pillar cut and fill mining complex is currently producing nickel sulfide in Northern Manitoba. From 2006 this area has shown a steady increase in the annual production, rising from 11 million pounds to 25 million pounds in 2010, and accounting for 33% of the total production for the Manitoba Operations. It is expected that fine-tuning the mining process can safely enhance ore recovery, improve production consistency, and increase economic viability of the deposit. The Post-Pillar Optimization study was initiated by the local technical and operational departments at the mine and analyzed from July 2010 to March 2011. The purpose of this study was to determine if portions of non-recoverable pillars can be slashed without jeopardizing pillar strength. This ideal case would optimize ore recovery and reduce variability in the ore mining rate. Numerical modeling and geo-mechanical material properties analyses, completed by the rock mechanics group, define the maximum drift width at 32 feet and the minimum pillar width at 18 feet. Thus, it was suggested that up to 3 feet could be slashed from two sides of the standard 24 foot pillars without damaging ground integrity. The field data collected indicates that additional ore could be recovered without compromising the safety of the workplace and the integrity of the complex. Consequently, technical and operational groups work jointly to achieve pillar optimization. Approximately 500,000 pounds of nickel was extracted from the complex via pillar optimization from July 2010 to March 2011. Economic analyses show the pillar optimization method developed for the mining complex is a proven, value-added opportunity. The mining complex remains a safe workplace and has retained ground integrity.

Nov 1, 2011

By K. D. Bulin

"An interesting brief history review of shovels as the primary excavating tool will permit the reader to see that immeasurable development and resources have preceded the shovel excavators which today are used extensively throughout the mining industry. With this as a background, the shovel manufacturer has the ability to utilize his resources best in those areas of shovel development in which the maximum benefits of increased reliability, performance and ease of maintenance will improve the operating rewards to the user of the equipment. The author explains the function of the shovel as a part of the material handling system. A detailed description of those areas of the shovel in which the most recent developments and major improvements have been implemented in the manufacture of the shovel excavator arc included."

Jan 1, 1973

By R. Panchadhara, P. A. Gordon

"A non-local formulation of the classical continuum mechanics theory called peridynamics is used to study driven dynamic fractures in the near wellbore region. The controlled application of pressure on the inner walls of the borehole can create multiple fractures that initiate from the borehole and propagate radially outwards. The number of fractures and their final length is primarily controlled by the loading conditions and the in-situ stress state. It is the objective of this study to use a novel numerical technique called peridynamics to investigate: 1) the influence of loading conditions on the fracture pattern, and 2) the effect of in-situ stress anisotropy on fracture propagation. In peridynamics, the momentum equation from the classical theory of solid mechanics is replaced with the integro-differential momentum equation of peridynamics. As a result, discontinuities in the body, such as fractures, occur spontaneously. The material is represented by a continuum body with material points that interact non-locally with all other points within a specified distance. Fractures evolve using a damage evolution law, wherein, damage at any point is represented as the ratio of the number of broken bonds in the current configuration to the total number of bonds in the undeformed configuration.Simulations are performed on simplified test cases and the results are compared to relevant experimental and numerical studies found in the literature. It is shown that the loading rate significantly influences the number of fractures initiated from the borehole as well as their extent. Low loading rate produces fewer fractures, whereas, high loading rates produce longer and a greater number of fractures from the borehole. The numerical method successfully predicts the fracture pattern obtained from a wide range of loading conditions. Predictions also indicate that the resultant fractures are shorter when in-situ stress is applied. Numerical results show that the fracture extension is largest in the direction perpendicular to the minimum compressive stress for the range of loading rates used in this study."

Jan 1, 2015

By W. P. Campbell

Foreword At the outset, it should be stated that this paper does not pretend to present a panacea for the ills that 'frozen' wells are heir to, but rather is an attempt to bring to the attention of those whose special concern it is, a little theory and some facts, which have been brought to light recently, in connection with the problem of 'freezing' as it applies to naphtha-producing wells in the Turner Valley field, and to draw some conclusions that follow from the facts discovered. It should also be stated that the investigation is not to be regarded as in any sense complete, but in progress. Doubtless new facts will be brought to light from time to time which may modify present ideas on the subject, but whether favourable or contrary, these will be welcomed, as the purpose of the Department is to secure as complete information as possible of the factors contributing to 'freezing', since this must be the first step to an intelligent attempt to remedy or prevent its occurrence, if such can be done. It is possible, too, that the cause or causes of freezing may not be the same in all cases, but whether this be so or not will have to be determined later as new information comes to hand. Introduction One of the worries which must constantly confront the operators of gas-naphtha producing wells in Turner Valley-although all, fortunately, have not met with it-is the possibility of the occurrence of what is commonly called 'freezing' (going off production).

Jan 1, 1930

By C. Xiao, F. Mohamm, A. Borsoi

"Nitrogen compounds produced by cyanide destruction and/or blasting are often a cause of concern for environmental compliance and at times, for water re-use in metallurgical circuits. Natural attenuation in tailings ponds and wetlands is not always sufficient to ensure compliance and/or achievement of overall water management objectives. This paper provides a general overview of active treatment methods for nitrogen management followed by an investigation of selective adsorption combined with electro-oxidation as the potential treatment method for thiocyanate. Results from bench scale treatability study are presented. The concept of holistic assessment of nitrogen management at mine sites using Risk Adjusted Life Cycle Cost is introduced and discussed in the context of gold mining operations using sodium cyanide.INTRODUCTION Unlike metals, nitrogen compounds present in mine waters originate entirely from anthropogenic sources rather than mineral deposits. Table 1 summarizes the main sources of nitrogen compounds reporting to mine wastewater.The best management practice related to the use of ANFO involves minimizing contact between ANFO and water, control and monitoring of blasting to reduce the occurrence of misfires, and reducing the consumption of blasting reagents for a given ore body. The most common practice for the management of NaCN is the incorporation of cyanide destruction in the metallurgical flowsheet and the use of tailings impoundments and holding ponds for natural attenuation of cyanide destruction residues such as NH4-N and CNO. At most mine sites there is no active management of NO3-N and SCN in wastewater. While current practices have produced satisfactory results, new enhanced methods to manage nitrogen compounds at mines are needed due to: 1) Increased scrutiny over the adverse effects of nitrogen compounds released into the environment; 2) New effluent standards; and 3) The shift away from wet tailings towards dry stack systems resulting in diminished natural attenuation and dilution of nitrogen residues prior to effluent discharge or water re-use in mineral processing."

Jan 1, 2017