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By D. H. Garcia

The mining industry responded to public concerns about use of cyanide by developing a voluntary certification to allow companies to demonstrate their commitment. The International Cyanide Code (Code) establishes standards for the manufacture, transportation and use of cyanide. Key concepts in closure planning to comply with the Code are to decommission all facilities related to cyanide operations and to provide a financial assurance mechanism for those activities. Code requirements may differ from state-specific regulations, but requirements are based on closure goals for protection of the human health and the environment. Only issues related to cyanide operations are required to be included in decommissioning demonstrations. For example, the disposal method of cyanide solution holding tanks and the cost must be included in the closure plan, but information regarding closure of roads is not required. Closure costs must be based on a third-party contractor as opposed to internal budgets. Compliance with the closure requirements of the Code allows companies to show their stockholders, lending institutions, and the public that their operations are environmentally responsible.

Jan 1, 2010

By A. M. Ramalho

In the synthesis and sintering processes to obtain superhard materials, such as diamond and cubic boron nitride, deformable ceramic capsule is used as gasket to transmit and support the required high pressures and high temperatures, HPHT. The ceramics materials for these capsules should have special physics and chemical characteristics such as refractoriness, shear strength and compressibility. In this work, Bridgman?s anvil made of hard metal or speed steel was used to characterize some ceramics materials in terms of their maximum compressible thickness. Tests were also performed with different resin polymers used as binding mixture with ceramics powder. Chemical analyses and investigations through scanning electronic microscopic (SEM), X-ray and real tests for the synthesis of diamond were also performed. The results showed that local Brazilian calcite can be successfully used in the manufacture of HPHT gaskets.

Jan 1, 2006

By W. G. Pariseau

This contribution focuses on the role of stress analysis for mine planning and the selection of suitable computer programs for the task with special emphasis on coal mine pillars. In this regard, barrier pillars that defend a set of five main entries at the Crandall Canyon coal mine in central Utah were formed during extensive longwall mining north and south of these main entries. Numerical analysis for ground control guided the mine planning and permitting. Retreat mining of pillars led to disastrous events August 6 and 16, 2007, with the loss of nine lives. A most difficult lesson taught by the Crandall Canyon tragedy is the need for education in the selection and use of computer programs for pillar design. Much of this contribution is taken from a report prepared for the Mine Safety and Health Administration (Gates, et al, 2008). Details appear in Appendix Q of the report (Pariseau, 2008). The Crandall Canyon mine is about 16 miles west of Huntington, Utah, in the Wasatch Plateau coal field. Geology of the Wasatch Plateau is described by Doelling (1972) as gently dipping Cretaceous sandstones, mudstones, coal seams, and shales. Joint systems are present in strata above and below coal seams where cleat systems are present as described by Hucka (1991). Several major fault systems transect the field and form grabens with 450- 760 m of drop. One such structure is Joes Valley fault that crosses the Crandall Canyon mine. Mines in the Wasatch Plateau are generally developed from outcrops in steep canyon walls. Overburden increases rapidly as mining progresses into the plateau; mining depth varies with topography between 450 and 600 m in the region of interest. A stratigraphic column derived from a borehole into the mine is shown in Figure 1. There are 11 layers in the column.

Jan 1, 2011

By Larissa Carolina Ferreira

O impacto das atividades do setor de mineração sobre o meio ambiente tem levado a estudos visando, tanto à utilização racional dos recursos naturais, quanto o tratamento de efluentes gerados durante os processos. A caracterização de efluentes é uma etapa importante, podendo apontar erros nos processos de beneficiamento, parâmetros em desacordo com a legislação ambiental e guiar etapas de desenvolvimento de técnicas do tratamento. Este trabalho consiste na caracterização de um efluente da etapa filtragem de uma mineradora de minério de ferro do quadrilátero ferrífero comparando os valores encontrados com as exigências da norma CONAMA 357/2005 e 430/2011, de forma a enquadrá-los na categoria de águas doces classe 1 e de lançamento de efluentes. O pH encontrado (9,8), turbidez (2133 NTU) e sólidos sedimentáveis (28mL/L), estão fora dos padrões permitidos e mostram grandes problemas em relação aos sólidos presentes na amostra. O diâmetro médio das partículas (8,54µm), indicou a predominância de partículas ultrafinas de difícil sedimentação. Os elementos majoritários Al, Fe, P e S, 0,296; 1,6; 0,218 e 26,5 mg/L, respectivamente, também apresentaram valores acima do permitido para água doce classe I. As análises indicaram que o efluente necessita de tratamento prévio para posterior descarte.

Aug 16, 2017

By Eric Jacobs

"Building and operating tunnels has been a highstakes endeavor in terms of costs, complexity, safety and impact on contractors, owners and the public for a long time. There are many variables that need to be closely monitored and managed to construct a tunnel on-time, on-budget and safely. Once built, there are also many elements that need to be monitored and managed to operate a tunnel safely and efficiently.Fundamentally, the risks to the safe and efficient construction and operation of a tunnel are a function of the degree of harm and the likelihood of the harm occurring. From a cyber security perspective, risk assessments used to inform decision makers and support risk responses are typically based on identification of relevant threats; internal and external vulnerabilities; the impact that may occur given the potential for threats to exploit vulnerabilities and the likelihood that harm will occur. This article focuses on creating awareness of vulnerabilities associated with technology used in tunnel construction and operation and some of the challenges associated with remediation of these vulnerabilities. As we all know, technology has been evolving at an accelerating pace and infiltrating every aspect of our lives in new and often exciting ways. In the world of tunneling, sensors and systems that provide position and time have become accurate, rugged and cost-effective enough to come out of the research labs and into the equipment and systems used every day. There are many opportunities to employ connected computing devices and sensors to costeffectively capture, integrate and analyze key data with minimal latency to manage risk better, improve safety and avoid surprises."

Jun 1, 2019

By Joachim Klein, Frank Reimann

Nodular-graphite cast iron (GGG) is a material similar to steel, and one which exhibits excellent properties, in particular for components exposed to pressure. GGG cast iron has been used in many cases when sinking mine shafts with conventional tubbing. With linings made of cast iron tubbings (the backfill concrete is not integrated into the calculations, and merely serves as bedding) the properties of the cast iron can be made full use of, provided the tubbing is made to the appropriate cross-section. Calculations have shown that better static values can be arrived at when using cross-sections other than those of tubbings made to conventional German standard. The cross-sectional design of the new types of shaft lining made from GGG is to be developed on these lines irrespective of the cast iron structure being only stressed component or its restistance function being combined with the one of concrete. GGG 50 is used for the first time to make the reinforcing inner liner of a main shaft currently sunk in Germany. The physical properties of nodular-graphite cast iron, strength and deformability, suggest that, in the future, its application will not be restricted to shaft support but also in tunneling. New moulding techniques with better three-dimensional modelling resulted in new tubbing designs as installed e.g. for the Hannover underground at present. Shield-driven tunnels have to withstand earth and water pressure, apart from axial machine loads. In this field time is money as well. Therefore easy handling and quick installation are necessary for successful, use. Last but not least, safety is of first-order importance for work in shaft sinking and tunneling. Cast iron lining systems, accordingly, are adequate systems, in particular for excavations underneath water for transport systems and for goods and passengers.

Jan 1, 1987

By David A. Hall

We present an analysis of the propagation in a uniform tunnel of semi -circular cross section that contains two axial conductors. In particular, we show that, even if one of these conductors has high ohmic loss, one of the two propagating modes has relatively low attenuation. This corresponds to the situation where an unloaded dedicated wire is used to improve radio frequency communication in a mine tunnel that contains a heavily loaded trolley wire.

Jan 1, 1978

By Leslie McHattie

?Intelligent mine? conjures up a futuristic image of unmanned extractors and loaders working in harsh conditions in a remote lunar landscape. The promise of increasing mine fleet productivity and solving the problem labor shortages in mining regions can certainly be achieved today through remote controlled extraction and automated hauling. The technology is available and it doesn?t seem to be so much science fiction when Google?s self-driving cars hurtle down the freeway. ?Intelligent mining,? on the other hand, implies the application of information technology at every phase of the mining value chain, from exploration and geological modeling to equipment, operations and maintenance, and logistics and transportation. These are really industry-specific, enterprise-class software solutions focused on using information technology to support the business processes of mining and make them more efficient and effective. Overlaying the physical world with the digital or virtual world enables us to model and simulate our assets, giving us the ability to effectively design, build, and ultimately optimize the performance and reliability of our assets throughout the lifecycle. The digital asset, often a 3D model, is created initially during the engineering and construction phase, and is handed over to the operator before the mine goes into operation. Combined with geospatial or geographic information systems, the operator has a complete digital representation of the physical world, which forms the foundation for risk and performance management, along with compliance and regulatory reporting. Laser scanning and positioning technology can be used to create point clouds ? information models consisting of millions of data points ? which enable the visualization and representation of the ?as-operated? reality. But consider that once the mine is in operation, it throws off an endless stream of data in the form of performance and condition data from sensors and monitoring devices on fixed and mobile assets through networks, servers, and services. This ?big data? can be processed and analyzed to spot trends, help predict events, and formulate reliability strategies as early as the design stage (e.g., reliability-centered design). ?Intelligent mining? implies that massive amounts of data augment the reality of the physical mine, plant, and equipment. This embedded intelligence can be used to optimize operational efficiency, increase asset availability and utilization, improve safety and environmental integrity, and maximize return on investment. Lastly, the sweet spot for intelligent mining is seen in the convergence of consumerization and industrialization. The application of ?consumer? technologies that we use every day on our iPhones and Android devices, such as cameras, motion sensors, and positioning in an industrial context, are producing ?immersive? experiences. Overlaying the digital world on the physical world and connecting them accurately through intelligent positioning results in ?intelligent infrastructure,? which is safer and more sustainable. Bentley Systems works with many mining companies and engineering, procurement and construction companies involved in all aspects of mining infrastructure development. In fact, 10 of the top 20 mining companies ranked by market capitalization are users of Bentley software, including all of the top five. In addition, Bentley provides software solutions to the world?s leading engineering, procurement, and construction companies, as well as owner-operators, who design, build and operate the world?s infrastructure. Bentley?s solutions for mining and resource extraction industries help increase the efficiency of capital projects associated with the design, procurement, and construction of mines and processing plants, as well as the operation and maintenance of mining fleet and equipment.

Aug 1, 2013

By Sam Kangwa, Thomson Sinkala

In the mining industry, drilling accuracy has a significant effect on the economy of operations. In this paper, results from the Nkana Division of the former Zambia Consolidated Copper Mines are presented. For the stope investigated, it was found that the extra operational costs alone were 462% of the planned costs! Clearly, there is more than good reason to pay attention to drilling of good quality holes.

Jan 1, 2004

By C. E. Gregory

In terms of a Research Proposals supported by a Grant Agreement dated 30 June 1973, the author was commissioned to prepare an annotated bibliography of mine fires. The main objective was to conduct a comprehensive program of library research and search of official files to prepare a list of articles dealing with actual occurrences of mine fires. This bibliography as now completed includes an annotated reference from each article or report cited, underlining the cause, extent, methods used, procedural errors made, results achieved, ventilation effects, and lessons learned from the operation of subduing the particular fire.

Jan 1, 1974

By Diana Drinkwater, Tim Napier-Munn

"This paper argues that, although specialist mineral engineering expertise is essential for the efficient design and operation of mineral processing plants, the environment in which these skills are supplied to the industry has changed forever, and not for the better. Most of the mineral engineering programmes in western universities have died or are dying. The long-service mine site mentors have gone, operations are run on a staffing shoestring so that there is no longer the time (or inclination) for considered decision-making, and the FIFO model has discouraged continuity of optimisation projects and communication between professionals. At the same time the technical challenges of designing and operating effective process plants are increasing. These trends are not going to be reversed any time soon, if ever. The ability to run efficient mineral processing operations has been materially compromised as a consequence. We propose that well-designed professional development can help to recover this situation, and it can be done easily and cheaply. The workplace is the best environment for such skills development. Professional development training should be integrated with normal duties throughout the early years of a graduate’s service (and probably beyond), and the cost should be regarded as non-discretionary expenditure for the business. If such programmes are properly resourced and managed and extended over longer time periods, there will be a measureable rise in the level of technical understanding and competence within companies and a resulting beneficial impact on resource utilisation and thus shareholder value. The paper outlines some of the approaches that we believe will work, and the benefits that we expect will accrue."

Jan 1, 2014

By L. Li

The backfilling of underground stopes is a common practice throughout the mining industry. The stresses imposed by the backfill on the surrounding rock mass need to be assessed because of their influence on ground stability and on the hydro-geochemical response of the fill material. There is, however, a complex interaction between the relatively soft backfill and the much stiffer adjacent rock mass. In recent years, the authors have presented results from investigations conducted on stress distributions (obtained numerically and analytically) in and around backfilled stopes with (sub)vertical walls. In this paper, the influence of stope inclination and of backfill properties is evaluated. Results indicate that, in general, the vertical and horizontal stresses in inclined stopes are close to, but somewhat smaller than the stresses in vertical stopes. Nonetheless, significant differences can be observed in some cases, especially for the vertical stress along the inclined central line and along the hanging wall. It is further shown that neglecting deformability in limit equilibrium analyses is an acceptable assumption. However, Poisson?s ratio and the dilatancy angle, usually neglected in limit equilibrium analyses, may have significant effect on the stress distribution. Results also confirm that the backfill strength parameters (cohesion and friction angle) are critical factors required to properly evaluate the stress distribution, at least within a certain range of parameter values.

May 1, 2007

By S. McPhail, D. Richardson, G. J. Simandl, C. Akam, S. Paradis, M. Yakimoski, A. Teucher, Y. Cui, F. Ferri

Historically, extracting dissolved solids from formation water was economically motivated. Today, main drivers are environmental benefits and regulations, as large volumes of water needed for hydraulic fracturing require treatment before reuse or disposal. The concentration of dissolved solids in flowback water increases with each use and may require treatment prior to disposal. Element recovery from produced water is not profitable unless market conditions are favourable, recoverable elements are abundant, and economical recovery methods are established. Sale of recovered materials could offset recycling and disposal costs. This paper describes markets for Cl, Na, Ca, K, Sr, Mg, Br, Ba, I, B, and Li, and their concentrations in produced water from oil and gas wells in British Columbia. It recommends revising sampling protocol for produced water.

Jan 1, 2018

By Orica

Unlicking the Possibilities ISEE Digital Detonator Workshop New Orleans, LA Wednesday, February 4, 2004

Jan 1, 2004

By J. W. Craig

CHROME ore, which is used in Canada in the production of ferro-alloys, in a variety of refractories, and indirectly in many chemical industries, is both commercially important and scientifically interesting. The sight of chromium metal is familiar to all of us in the home, the office, the automobile. Chromium is synonymous with armaments: it is understood to be one of several essential metals in tanks, which played an important role in the defeat of France in the spring of 1940. Chromium, in other forms, comes into our daily lives by way of paint and leather, of the familiar green ginger-ale and beer bottles, and more indirectly in every pound of steel produced in the .Dominion. Necessary to our civilization in peace and war, the ores of chromium occur in many corners of the earth. This paper attempts to describe the chemical constitution of chrome ores, their world distribution, and the various chrome products and their industrial applications in Canada.

Jan 1, 1940

By E. D. Gardner

This paper is the third of a series of three on placer mining in the western United States. The first paper4 discusses the history of placer mining in the Western States and the production of placer gold, geology of placer deposits, location of placer claims on public lands, sampling and estimation of gold placers, and classification of placer-mining methods, together with hand-shoveling and ground-sluicing. The second papers deals with hydraulicking, sluice boxes and riffles, recovery of gold and platinum from placer concentrates, treatment of amalgam, and marketing of placer gold. The discussion of sluice boxes and subsequent subjects in the second paper applies to all forms of placer mining. The present paper treats of dredging and other forms of mechanical handling of placer gravels, and drift mining.

Jan 1, 1934

By W. G. Pariseau

Conventional barrier pillars in underground coal mines are intended to protect mains and sub-main entries for relatively long periods of time. Inter-panel barrier pillars that may be used in especially deep coal mines, say, below 800 m (2,400 ft), are intended to protect longwall panel faces and adjacent panel entries for the life of nearby panels. Barrier pillar failures have serious consequences, especially when failure is sudden and catastrophic. Design of barrier pillars is thus of considerable importance to safety and efficiency of operations. Locally, failure occurs at the limit to elasticity when stress tends to exceed strength. Strength of rock is stress dependent, so an analysis of stress is central to rational design of barrier pillars. There are several approaches to stress analysis for coal mine pillar design that range from the simplified but popular tributary area method including variations that use empirical definitions of the tributary area (volume) to more sophisticated numerical methods such as the boundary element method and the finite element method. Despite ease of use, empirical methods are limited and always suspect when applied to conditions beyond their scope of definition, while boundary element methods do not generally include pillars in the solution domain. The finite element method is not so restricted and thus is a natural choice for conventional and inter-panel barrier pillar safety analyses. Caving of roof strata certainly affects the distribution of stress about longwall faces and nearby barrier pillars. Conventional wisdom that considers roof strata to respond as cantilever beams indicates the longer the span the greater are loads on longwall faces and face supports. Failure of roof beams, caving, shortens spans and relieves face and support loads. The same view is applicable to barrier pillars in that long roof spans outside of barrier pillars leads to higher pillar loads than short spans. Hence, caving should be beneficial to barrier pillar safety. However, the benefit may be small depending on the extent of caving and only in the form of a slight reduction in overburden weight transmitted to the barrier pillar, especially in case of inter-panel barrier pillars. FINITE ELEMENT MODEL Finite element models for stress analysis in rock mechanics are formulated in consideration of physical laws, kinematics, and material laws. These models meet the essential requirements for equilibrium of stress, satisfy strain displacements relations, and in a general sense, relate stress to strain through material laws, often referred to as constitutive relations. The last may be complex and replete with nonlinearities. A de facto engineering material law is the elastic model in the form of Hooke?s law for linear, homogeneous materials that may be anisotropic. A limit to elasticity is imposed by strength in the form of a failure criterion or yield function that accommodates triaxial stress states. Examples used in rock mechanics are the well-known Mohr-Coulomb (MC)criterion, the popular Hoek-Brown (HB) criterion, and the Drucker-Prager (DP) criterion. The first is linear in stress, while the second is nonlinear. Both do not include any effect of the intermediate principal stress. The last is also linear in stress but includes the intermediate principal stress. All show an increase in the major principal stress at failure with confining pressure. In the UT2/3 finite element programs, the failure criterion Y is a nonlinear, anisotropic form and is also the plastic potential [1]: [YJI=+ 11NYJI=+- (1) ] where N is an exponent, usually 2, and J2 and I1 are nonlinear anisotropic forms of the second invariant of deviatoric stress and the first invariant of principal stress. The form (1) reduces to DP when N=1and isotropy prevails. When Y = 1, the limit to elasticity is reached and plastic deformation is possible. The material constants that enter (1) are all computed from unconfined compressive, tensile, and, in case of anisotropy, shear strengths. These latter strengths may be estimated from conventional laboratory test data. Of course, joints in field-scale rock masses induce different values. How different is often a matter of conjecture. For comparative studies, laboratory rock properties seem adequate. Inelastic, that is, plastic behavior occurs with strain beyond the elastic limit. Strain hardening, ideal plasticity, and strain softening are possibilities. Ideally brittle behavior with complete loss of strength is an extreme form of strain softening [2]. Caving may also be considered as strain softening with a less drastic reduction of material properties. As intact roof strata fail, fall, and form a rubble pile below, a new material is formed with greatly reduced elastic moduli and strengths, say, 1/100th of the original intact moduli and strengths. From another viewpoint, caving is simply a natural cut and fill process. Input for stress analysis by the finite element method includes: 1. Preexcavation stress state 2. Geology (stratigraphic column) 3. Structure (major faults, joint sets) 4. Elastic moduli 5. Strengths, and specific gravities of each rock type 6. Excavation sequence Output from an analysis includes distributions of: 1. Stress 2. Strain 3. Displacement 4. Local factor of safety (element fs) The last is defined as the ratio of strength to stress and in view of the failure criterion (1), is the ratio [fsJstrengthJstress=] where the numerator is the maximum possible value and the denominator is the actual value of the square root of the second invariant of deviatoric stress. This invariant is a measure of shear stress intensity but also reduces to uniaxial tensile and compressive strengths as the case may be. An fs greater than 1 indicates an elastic state of element stress; a value of 1 indicates the limit to

Jan 1, 2009

By Roberto Vargas

"El presente Trabajo de Investigación, tiene por objeto describir la tecnología, la operación del Proceso en la Planta que implementa dicha tecnología así como los resultados obtenidos en dicho Proceso y aplicaciones de la tecnología a otros tipos de concentrados de cobre (Enargita). "

Sep 1, 2017

By D. Harrington

Coal mines and mining-, as well as metal and nonmetallic mines and min¬ing, are not inherently unsafe, although mining people think they are and would like to have everyone else think so. It is now being demonstrated that mines can be operated with essentially as much safety as any other major industrial enterprise; but most mining people, including workers as well as officials, have been slow to realize or admit this. In the past, and with most people even at present, the idea has prevailed that it is utterly impossible to operate a mine without accidents. Although, as in all other kinds of industrial activity, it is true that some injury is likely on occasion to occur to some workers and an extraordinary accident may occur to one or more persons under exceptional conditions, mines can be operated with few if any accidents if a reasonable amount of the right kind of precautionary effort is exerted and kept in effect.

Jan 1, 1934

By James A. Madonna

Information gathered while studying geological parameters that govern fine gold deposition in the a1luvial environment can be applied to the technological development and selection of fine gold recovery systems. It is recognized that substantial gold losses occur in the minus 1.5 mn (minus 12 mesh) fraction using conventional sluicing systems. Within the past two decades much attention has been given the design and efficiency of these thick bed concentrators. Studies and comparisons drew information from several foreign and domestic placer operations. These studies concentrated on: 1) the physical and chemical properties of alluvial gold 2) the parameters that control fine gold deposition 3) the geometrical form, components and general working structure of conventional sluicing systems 4) the physical properties which contribute to the overall efficiency of a sluice system 5) the comparison of three major styles of conventional sluicing systems. A dramatic improvement regarding fine gold recovery and water quality was observed when using modern multiple-channel sluicing systems in place of conventional single-channel sluicing systems.

Jan 1, 1988