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By Jan Drzymala, Przemyslaw B. Kowalczuk

"Flotation is possible when the forces operating between a bubble and the attached particle are properly balanced. There are many forces operating in the bubble-particle aggregate. The magnitude, location and direction of the forces depend on the type of process. The simplest arrangement in flotation is when a spherical bubble is attached to a spherical particle and both are immersed in water. In such a system there are four essential forces which shape the stability of the bubble-particle aggregate. They are excess pressure and interfacial solid/liquid, solid/gas and liquid/gas forces. A proper analysis and balance of the size, location and direction of these four principal forces lead to a general equation delineating the stability of the spherical particle–attached bubble system. Specific cross sections of the system and solution of the general equation lead to different relationships including the Young formula as well as the well-known geometrical relation between contact angle, particle and bubble radiuses. The arrangement of forces in the proposed graphical representation of the Young law is different from that presently used in literature for a bubble attached to an unmovable solid particle. Many real solid/liquid/gas systems are more complex due to the presence of additional forces which change the regular curvature of the liquid/gas interface leading to advancing and receding contact angles.INTRODUCTIONThere are numerous papers (Athukorallage, Aulisa, Iyer & Zhang, 2015; Chau, Bruckard, Koh & Nguyen, 2009; Drzymala, 1994; Lubarda, 2012; Pellicer, Manzanares & Mafe, 1995; Wang, Cui, Zhou, Xu, Sun, & Zhu, 2014; Young, 1804) and books (Davies & Rideal, 1963; Defay & Prigogine, 1966; Lee, 2013; Lyklema, 2000) dealing with the solid/liquid/gas system. Many of them concern the three involved phases having the shape of a sphere or spherical cap and the formed contact angle. The contact angle is usually measured through the liquid phase and can be either smaller or greater than 90o. The essential part of these publications is a graphical representation of the system with the Young equation shown as a result of balance of only three forces that is the excess Gibbs (or Helmholz) free energy per unit area of the three involved interfaces (Davies & Rideal, 1963; Defay & Prigogine, 1966; Israelachvili, 1985) (Figs. 1a-c). The Young equation, when the gravity force/buoyancy is neglected, is:"

Jan 1, 2016

By T. G. Joseph, M. Welz

ABSTRACT: Joseph (2002) introduced passive seismic monitoring to measure mining equipment performance. This paper evaluates the potential of passive seismic monitoring to correlate mining equipment operation with oil sands surface response, with a mining hauler as the seismic source. When applied to moving haulers, this action–reaction approach is complex. Vibrations from on-board equipment, such as pumps and tires, dirty the signal with noise. To facilitate any correlation, the signal must be cleaned up. Existing geophysical analytical techniques were manipulated to evaluate the noise problem and to filter sufficiently to permit an evaluation of whether a mining equipment action–ground response relationshipis in fact discernable.

Jan 1, 2011

By A. G. Slade

"This paper deals with the direct application of rock mechanics in the underground mines at the Sudbury Operations of Falconbridge Nickel Mines Ltd. It covers mining methods, the use of photoelastic models, the fore-casting of rock strains and their elimination, closure methods and other common methods of ground control.INTRODUCTIONROCK MECHANICS IS A STUDY IN ROCK BEHAVIOUR and, although it is being termed a new science, it has been practiced since the industry began. Every person involved with rock excavations, from the mine superintendent to the stope driller, is actually practising rock mechanics. They probably call it by another name -experience, and applications of this knowledge are in evidence throughout the Falconbridge operations. Only in recent years have formal rock mechanics studies been employed to provide technical assistance to the mine operators in their primary objective of producing ore safely."

Jan 1, 1968

By D. S. Evans

Major Project Blues Over the last two decades, almost every major project has suffered significant cost overruns, significant schedule delays, and/or poor quality work. Exceptions are rare and most projects that tout being ?On Time and Under Budget? have re-cast schedules, significantly modified scope or revised base estimates. The problem isn?t new. In the late 1980?s the Rand Corporation published a study showing that 80% of all major projects had significant cost and schedule overruns. The problem is not restricted to the Canadian environment, or to a specific industry. It is a global problem.

May 1, 2013

By J. R. Bradfield

THOSE familiar with the development of the Horne mine can readily appreciate that more and more accommodation bas been required for underground labour as the mine has grown. A permanent fire-proof change house, 30ft. by 75 ft., was built in 1927 to accommodate 194 men. This was extended ro 30 ft. by 92 ft. in 1928 to accommodate 296 men, and to 30ft. by 110 ft. in 1930 to accommodate 398 men. By 1933 this building was again overcrowded and tentative plans for a new change house were drawn up. However, it was realized that future operations would be centred around No. 4 shaft and a proposed new shaft, and the decision as to the location of the new change house had to be deferred until the area which seemed most suitable for the new shaft had been thoroughly explored underground. In the spring of 1934, the basic idea was accepted of drying the wet clothes in open mesh compartments or baskets located between rows of standard steel street-clothes lockers and built so that the covers or lids would serve as seats or benches.

Jan 1, 1935

By V. C. Wansbrough

First, permit me to say with what very great pleasure we find ourselves assembled in this most ancient and honourable city of Quebec. It is a city which we deeply respect as the fountain-head of the culture of French-speaking fellow citizens, and the seat of government of a province which is steadily recording new achievements in Canadian mining. Such achievements prove what can be accomplished when enlightened and progressive government policy, technical and scientific competence, and private initiative pull forward together in harmonious rhythm. It is a most happy and auspicious event also that the guiding control of the affairs of the Institute and of the fine traditions of provincial administration have for the past year been united in the person of our honoured President, Dr. A. O. Dufresne. This year, again, we have bad prepared for us by our hosts a splendid programme of technical sessions and social entertainment. Each year we pay an unspoken compliment to the Institute, expecting as a matter of course nothing but the highest standards in both these spheres. In its annua1, semi-annual, and regional meetings, in the constant activity of its local Branches, the Institute continues with marked success to perform its great dual service, social and educational. We are all its beneficiaries to the extent to which we choose to profit by participation in its affairs. But, one imagines, to none are the advantages of Institute membership more valuable than to young men embarking on their professional careers.

Jan 1, 1951

By Richard E. Barrett

SOME YEARS AGO I was associated with a mining operation which, because of its isolated location, burned wood for heating purposes. Year after year the tractors and tucks hauled the cordwood in from the edge of the ever-growing clearing. Each year the cartage costs became greater. The degree to which transportation distances affect the economics of fuels obviously varies with many factors, but the main criterion is the amount of heat a unit weight of the fuel will produce. For in-stance, wood is limited in most cases to a haulage distance of a few miles. Coal can be shipped hundreds of miles, whereas petroleum and gas ?can be transported thousands of miles. The world is now on the brink of having a new fuel -uranium. It has the virtue of being so concentrated that transportation costs can, for all practical purposes, be disregarded.

Jan 1, 1958

By Alex Henderson

The underground hard rock mining industry has had little change since the mobile equipment era began in the 1970s. Equipment has become larger and faster but has not kept pace with the following challenges: ? Improvements in safe production, ? Increasing demand for metals, ? Environmental improvements, ? Decreasing grades, ? Increasing depth of mining, ? More metal from underground vs. surface mining, and ? Energy and green house gas awareness. We are on the cusp of a new mining era and must rethink how underground hard rock mining must change in order to meet these challenges. This paper will show historical changes and propose a set of guiding principles for the next era of mining. Mining has changed over the last century. Initially mining was primarily an endeavor carried on by private companies with minor environmental controls and few social expectations other than employment. In the mid to later part of the century the mining industry was facing new challenges: deeper mines, the London Metals Exchange markets for pricing, and environmental concerns related to acidic rock drainage coming to the forefront. In today?s context, mining has evolved in complexity with the social and environmental aspects equally or surpassing the technical complexities such as expanding from mining hard rock to laterites, and mining lower grades or at greater depths. Nowadays, communities must be considered as partners, both locally and globally and the increased international visibility pushes the mining sector to take a more balanced approach to the business of mining (Fig. 1).

May 1, 2011

By W. H. Hastings

Introductory In the amount of her coal reserves, Saskatchewan ranks third among the provinces of the Dominion, with a total, as estimated by D. B. Dowling, of 59,812,000,000 tons. All the coal so far discovered in the Province is lignite, and it would appear unlikely that bituminous or higher grade coals exist. General Occurrence of the Coal The location of the coal-bearing formations in Saskatchewan is shown on the accompanying map. It will be seen that the areas lie principally in the southern part of the Province. The more darkly shaded areas indicate locations where development is taking place, or where coal-seams are known to occur, either through outcrops in valley-sides or through having been encountered during boring operations. The coal-seams are not necessarily continuous throughout the shaded areas, but in all pans of these there are coal possibilities. It is quite possible that small outliers of the coal-bearing formations may occur further north in the Province, but, generally speaking, coal is not likely to be found outside the shaded areas.

Jan 1, 1929

By K. Barbetti

"The carbon-in-pulp (CIP) process has been the dominant gold recovery process since the early 1980s. CIP has proven to be very adaptable for a wide range of ores and circuit configurations. The key performance indicator for CIP circuits is the minimisation of soluble gold losses to tailings, however, it is also important to operate the circuit efficiently (maximising gold loadings on carbon and minimising carbon inventory). Over the last 30 years the Curtin Gold Technology Group has studied CIP circuits as part of an on-going collaborative industry funded project (the AMIRA Gold Processing Technology Project). In the early years the project undertook basic research into understanding activated carbon, and its management in the circuit. More recently the development of process models and instrumentation has provided additional tools to assist operators. The results show that while most CIP circuits operate well, there are still significant opportunities for further cost savings, or additional revenue. This paper reviews the observations arising from this work, including key requirements for good carbon management, the results of benchmarking and industry surveys of carbon circuit over 20 years, the value of process modelling of CIP circuits to establish operating parameters, and the use of automated instrumentation to better optimise carbon control in the circuit.INTRODUCTION The introduction of activated carbon to recover gold from cyanide leach solutions in the last quarter of the 20th century was the most significant development in gold ore processing since the advent of cyanidation seventy years before. Replacing the Merrill–Crowe zinc cementation step with carbon-in-pulp (CIP) or carbon-in-leach (CIL) circuits provided a process that allowed the treatment of lower grade and problematic ores (e.g. high-clay ores), at lower capital and operating costs, and higher metal recoveries. The CIP circuit was first developed in the 1950s at the Carlton Mill, Cripple Creek, Colorado. All the components of the modern CIP process came to fruition at the Homestake Mine in South Dakota in 1973 (Fast, 1988). From the late 1970s onward a variation of CIP, carbon-in-leach (CIL) which combined the leach and adsorption stages, became the preferred circuit design in most parts of the word."

Jan 1, 2017

By C L. Briend, O&apos

This paper presents the main features of coal mining in Japan, as determined by the author while attending the International Coal Conference in October of 1963. The general economy of the country is considered, and the requirements for coking coal are outlined. Statistics and comments on production and consumption are then given, with accompanying cost figures, and the characteristics of Japanese coal mining are compared with those of Canada. Mining methods and underground transportation are covered, with emphasis on undersea mining. Finally, a description is given of a visit to the Miike colliery, the largest in Japan. I T was my privilege to attend the International Coal Conference held in Tokyo in October, 1963, to meet many prominent members of the Japan Coal Association and to visit one of the major coal fields. This is probably the reason why I was asked to present this review of the coal situation in Japan. In doing so, it must be pointed out that I am not an expert in coal mining, that my

Jan 1, 1965

By H. C. M. Gordon

MR. A. D. BADOUX: I have listened to Mr. Gordon's excellent paper with great interest, as I personally have gone through some of the experi­ences he has so clearly depicted. In particular, there were a good many times when we were greatly exercised in our minds as to whether we were justified or not in closing-off certain sections in the Allan mine. The difficulty in these cases arose from the fact that a peculiar smell could be detected in these sections but at the same ti me there was no positive evidence of spontaneous combustion either from heat being apparent or from the possible indications of fire getting any worse. It was suspected that the small percentage of -carbon monoxide that could be obtained by analysis in the air in these sections, and also the peculiar odour, were emanating from the coal itself, and, in order to verify this, bore-holes were drilled in the coal and the gases released from these bore-holes were analyzed. They were found to contain carbon monoxide. After quite a considerable length of time this contained carbon monoxide gradually diminished and finally could not be detected when analyzing such samples of gas. It was our intention to follow this matter up further, as such an occurrence of carbon monoxide is practically unknown, but the sections in which these occurrences were found had to be abandoned. Mr. Gordon referred t0 a case of spontaneous combustion in the Allan . mine, and I may say that, although the section in which that occurrence took place was travelled and carefully examined every day by the colliery officials, yet nothing unusual was noticed until the fire actually took place. This tire was the cause of a slight explosion.

Jan 1, 1938

By F. S. Su, P. Z. Pan, X. T. Feng, F. Yan, W. W. Ji

"This paper aims to simulate the spalling failure behavior in hard rock based on a self-developed numerical model, i.e. a rock discontinuous cellular automaton (RDCA). A crack initiation and propagation criterion is proposed based on the plastic strain, which is used to link the continuity and discontinuity during the failure process. The discontinuities of rock, such as cracks and other internal boundaries, are represented by discontinuous displacement functions, i.e. tip enrichment and step enrichment. The partition of unity is used to improve integral precision of the elements intersected internal boundaries, which is traced by a level set method. Arbitrary crack geometries can be conveniently represented and it does not require any remeshing in the modeling of crack initiation, propagation and coalescence. Numerical modeling of excavation in hard rock using RDCA is conducted. The spalling failure process of hard rock induced by excavation is well simulated. The depth and shape of hard rock spalling failure are good agreement with in situ observation.INTRODUCTIONThe excavation in rock mass is more and more popular. At the same time, the disasters, such as rock burst, rock spalling and falling etc, induced by excavation are quite prominent. Numerical modeling is an important way to help us understand the failure mechanism of rocks. Many numerical methods have been used to simulate the excavation of rock mass. For example, the finite element method (FEM) (Karakus and Fowell, 2003), the discrete element method (DEM)(Cundall and Strack, 1979, Labra et al., 2008), Finite difference method (FDM)(Zhu et al., 2009), Element Free Galerkin Method (Belytschko et al., 1994), Discontinuous displacement analysis (DDA) (Shi, 1988) and Boundary element method (BEM) (Katsikadelis, 2002, Chen and Hong, 1992) are commonly found in the stability analysis of excavation in rocks. In the modeling of crack propagation or excavation, most of these methods are tedious since the internal boundaries have to be consistent with the element boundaries. And in many cases, the remesh has to be conducted. In recent years, people are interested in particular types of FEMs, such as the extended finite-element method (XFEM), the particle discretization scheme finite-element method(PDS-FEM(Hori et al., 2005, Oguni et al., 2009)), the combined finite-discrete element method (FEM/DEM) (Munjiza and Wiley, 2004, Cai, 2008) and spectral-element method(Gharti et al., 2012) etc."

Jan 1, 2015

By B. Damjanac, S. Maxwell, D. Chorney, M. Grob, F. Zhang, J. Hazzard

"A hybrid discrete-continuum numerical scheme is developed to study the behavior of hydraulic fractures crossing natural fractures. The fully coupled hybrid scheme utilizes a discrete element model for a core domain, within which the hydraulic fracture propagates and interacts with natural fractures, and a surrounding continuum domain to better approximate boundary effects. The results show that the behavior of hydraulic fractures crossing natural fractures is affected by a combination of factors. Nevertheless, three fundamental crossing scenarios can be identified from all of the simulations: no crossing, partial crossing, and direct crossing. Each crossing scenario has a distinct injection pressure history which may suggest guidelines for interpreting field hydraulic fracture injection data. Additionally, the capability for these models to generate synthetic microseismicity makes them appealing for the integration of microseismic field data with the reservoir geomechanics for ultimately providing a practical engineering tool for improvement of well completion and stimulation. The model is capable of examining and verifying four different shear deformation mechanisms associated with a propagating hydraulic fracture. The natural fracture can fail solely due to the stress perturbation of the passing hydraulic fracture or it can fail due to a combination of stress and pore pressure changes across different types of interaction scenarios. The simulations also illustrate that the level of fracturing complexity increases as the number and extent of the natural fractures increase. INTRODUCTIONAlthough hydraulic fracturing technique has been applied extensively as a reservoir stimulation technique in the oil and gas industry for over 60 years (Economides & Nolte, 2000), it is one of the key factors promoting the shale gas boom in the past decade (King, 2010; International Energy Agency, 2014). The hydraulic fracturing of shales can be differentiated from hydraulic fracturing of conventional reservoirs by the fact that shale formations often have a pre-existing discrete fracture networks which greatly impact the hydraulic fracture propagation. Based upon field production data as well as microseismic observations, it is believed that so called “fracture complexity” may result from interactions between a created hydraulic fracture and pre-existing natural fractures and planes of weakness (Warpinski, 2009; Maxwell & Cipolla, 2011)."

Jan 1, 2015

By Matthew Scott

Introduction The refining of precipitate is the final stage of all the processes involved in gold mining and cyanide milling, by which the precious metal is at last obtained in a concentrated form, which can be accurately valued and marketed. Possibly one ought to say, conveniently shipped, for accuracy in valuation depends in many instances on a toughening treatment given the bars as received at the Mint so as to obtain a homogeneous metal that lends itself to representative sampling; which, of course, entails a surcharge on the regular Mint charges for the extra work necessarily undertaken. There are several methods of refining zinc-gold precipitate, each with its advocates; the method employed depending not always on the quality of the bullion produced but on the local exigencies of the case in point. These methods are more or less detailed in various textbooks and it is not the purpose of this paper to discuss them, but to confine ourselves to the specific case as stated in the title of the paper. At the outset, it behooves the writer to express his thanks to Mr. Brigham, the General Manager of the Hollinger Mines, for the kindly consideration and encouragement given in developing this process. This will be better understood when one considers the immense values involved, tending towards conservatism in practice, and making one chary of radical innovations. This process has been in satisfactory operation now for about two and-a half years, during which time over twenty-five million dollars value in fine gold has been produced, so that it may be reasonably held that the process is successful.

Jan 1, 1931

By Zetti Gavelán

Globalization and the search for new ore deposits inevitably lead to investment in foreign markets. Investors need to be aware of the effect of their venture on regional, social and economic issues when they invest. Decades of detailed statistics from various sources can be integrated and analyzed to predict the social-economic impact of investment, thereby mitigating risk. To this end, the correlation among variables such as foreign direct investment into mining (FDIM), reserves, and socio-economic indexes is examined. The investigation focuses on South America from 1992 to 2000. Throughout the past decade, South America has benefited from capital investment from more developed countries. This huge investment by the mining industry has impacted the South American economies and can be measured directly using the FDIM. Other economic variables investigated include mining gross domestic product, direct employment, and human development indexes. The correlation is based on data compiled from the World Bank, international risk assessment agencies, the United States Geological Survey (USGS), and the information agencies of various South American countries. Initial analysis of the economic data suggests various expected outcomes. For example, foreign investors may disregard a measured, highly negative country risk in deference to the quality of its mineral resources. It is important to note that the standard measures of country risk published by investment analysts are not industry or investor-specific. In the case of the investor, the level of accepted risk is based on their managed investment portfolio. It is noted that arguments for level-playing fields may be the antithesis of globalization. The discovery and exploitation of ore bodies in a globalized environment necessitates the development of economic measures that standardize mining-specific risk variables and trends. The latest published information on the security of mineral investments in South America is investigated by integrating databases of economic, geologic, production, human indexes, and risk ranking.

May 1, 2003

By G. W. Neumann

"In order to avoid pollution of water in Flemming Brook and Little River, which drain the area in which the Brunswick No. 12 Mine and Concentrator are located, the company has gone to considerable expense in preparing tailings storage and effluent setting ponds. The attached drawing gives a plan of the six settling ponds together with elevations of the dikes and the effluent weirs.All original dikes for the six ponds were constructed from humus-free clay and rock material, which was obtained, preferentially, by excavating from within the dike area. Run-off water, precipitated on the outside slopes of the dams will drain off without contacting the tailing material. A ditch was made north of the dam site to deflect surface run-off to the east into a branch of Flemming Brook.A secondary dike, made from tailings, has recently been erected on No. 1 and No. 2 tailings pond inside and above the earth-filled dike which serves as a roadway. Run-off from the tailings dikes will be retained inside the ponds by ditching between the roadway and tailings dike into ponds 4 and 6."

Jan 1, 1969

By Lauri Gregg

The implementation of Energy Management within the global mining industry has advanced significantly during the past 20 years. Consequently, the industry?s knowledge of energy efficiency improvement opportunities, more energy efficient technologies, renewable energy technologies, energy procurement practices, and most importantly, practical approaches for integrating the energy management best practices into business processes and operational procedures has improved greatly. Based on 25 years of experience leading the management of energy in mining operations and the Canadian mining community, the author discusses the key building blocks in the evolution toward becoming an energy efficient mining facility. Sustainable energy management depends on the internalization of the behaviors related to the effective energy use by a mining organization. The paper outlines the typical business drivers that stimulate top management commitment to allocate the resources necessary for this to happen. It also explores the barriers that mining companies must overcome to maintain the commitment. Additionally, it will advocate the need for the application of the principles of organizational change management as part of the energy management implementation process. The question regarding how energy management can be made to happen in a way that is practical for an established organization is answered by providing the details of the framework for energy management, the methodology for controlling energy use, and the roadmap for integrating energy as a key business parameter and production process input variable. An Energy Management System standard developed within the Mining Association of Canada?s ( MAC ) Towards Sustainable Mining ( TSM ) initiative has played an important role in increasing the capacity of the Canadian mining industry to manage energy. The impact of the application the MAC TSM Energy/GHG Management Protocol by Canadian mining companies will be discussed. In June of 2011, the international ISO 50001 Energy Management Systems standard was finalized and published for use. The structure of ISO 50001 will be outlined along with its applicability to the mining industry. Opportunities for practically improving mining energy performance along with the most appropriate current new technologies will be identified. A brief discussion of case studies will be included that demonstrates the successful implementation of Energy Conservation Measures ( EAC?s ) and economic benefits. In conclusion, thoughts on important areas of research and development related to increasing mining energy efficiency will be provided.

Aug 1, 2013

By A. D. McKay

Uranium exploration expenditure in Australia reached a record level of A$220.5 million in 2008, which has subsequently declined to A$185.2 million for the year ended 30 June 2009. Recent discoveries include: Ranger 3 Deeps east of Ranger open pit (Northern Territory), Pepegoona and Yadglin sandstone hosted deposits (South Australia), and Thunderball project (Northern Territory). Australia?s Reasonably Assured Resources recoverable at costs of <US$80/kg U at June 2009 are estimated to be 1,210,000 t U, 4% higher than the estimate for December 2008. The main additions were in the south eastern portion of the Olympic Dam orebody. The Olympic Dam Expansion is based on a large open pit and will increase output to an annual capacity of 19,000 t U3O8; 750,000 t copper; 800,000 ounces gold. The Four Mile in situ recovery project was approved in July 2009. An ion exchange facility is to be constructed at Four Mile and uranium-bearing resins will be transported to the Beverley plant to recover the uranium. Recent developments at Ranger mine, and Honeymoon, Oban and Yeelirrie projects are discussed.

Aug 1, 2010

By N. Vayenas, G. Yuriy

"The combination of a predictive reliability assessment model and discrete-event simulation can be an effective methodology to study the impact of equipment failures on the capacity of production systems in mines. In our case, a predictive reliability assessment model using genetic algorithms is combined with a discrete-event simulation model to analyze mine equipment systems.Discrete-event simulation involves modelling of real-life systems based on variables and events that occur or change at distinct points in time. The Simul8 simulation software, by Visual Thinking, is used in this research. It is a two-dimensional (2D), discrete-event simulation/ animation software tool for creating realistic depictions of manufacturing and materials handling systems.The simulation model developed for the purpose of this research represents a typical two-level, sub-level stoping section of an underground mine in the Sudbury region in Ontario, Canada. This 2D model was created to assess the impact of equipment failures to a mine’s production throughput. In more detail, using mean time between failures (MTBF) data of scooptrams derived from a reliability assessment model based on genetic algorithms, LHD failures are incorporated into the simulation model. These failures cause production interruptions to the development cycle and consequently loss of hauling capacity.Another purpose of this research work is to demonstrate how low-cost simulation tools such as Simul8 can be successfully applied to model underground hard rock mining operations. The research discussed in this paper is carried out by the Laurentian University Mining Automation Laboratory (LUMAL)."

Jan 1, 2005