Search Documents

By A. Perucho, J. P. Harrison, A. Bedi, L. Alejano, L. Lamas, A. Sofianos, A. M. Ferrero, R. Migliazza, R. Olsson, J-F. Mathier

"In 2010, the Eurocode for Geotechnical Design, EN-1997-1:2004 (CEN, 2004), informally known as Eurocode 7 or EC7, became the Reference Design Code (RDC) for geotechnical design – including rock engineering design – within the European Union (EU). EC7 is one standard within the comprehensive Structural Eurocode suite, which as a whole has been also adopted by a number of other countries beyond the EU. EC7 is thus becoming a key design standard for geotechnical engineering worldwide.As part of the Structural Eurocode suite, EC7 requires designs to adhere to the principles of Limit State Design. However, it is not clear that current rock engineering design practice can satisfy this requirement. In addition, evidence is accumulating that EC7 is currently difficult to apply to, and may even be inappropriate for, rock engineering design. These issues may be due to the fact that the development of EC7 to date took place without any formal input from the international rock mechanics and rock engineering community.In early 2011 under the auspices of CEN (Comité Européen de Normalisation / European Committee for Standardisation), EC7 entered a formal period of maintenance which was aimed at improving the applicability and ease-of-use of the Code. This maintenance cycle will conclude in 2020 with the publication of a revised version of EC7.This paper describes a number of critical aspects for rock engineering in the context of EC7, inparticular the following:– the history of the Structural Eurocodes and the concepts they embody;– the nature of Limit State Design and the challenges and opportunities it poses for rock engineering design;– the formal means by which the Structural Eurocode maintenance cycle proceeds;– the plans currently being developed for improving EC7 with regard to rock engineering design and construction;– the unique and vital opportunity for the entire international rock mechanics and rock engineering community to comment on the Code and make suggestions for its improvement."

Jan 1, 2015

"An innovative concept is proposed whereby the operating power for haul trucks in certain areas of an underground mine are reduced in order to lower ventilation costs. Airflow that must be provided for diesel-powered equipment in most jurisdictions are regulated based on engine peak power capability and engine emissions, both of which can be lowered by artificially reducing the capacity of the engine through the engine control unit. Advances in asset tracking and ventilation on demand enable this methodology and this study demonstrates that it could represent significant value for mine operators. An examination of haul truck duty cycle indicates that de-rating of engine operating power based on the truck’s location in the mine can enable a step change in ventilation rates, often with no material impact on working conditions. Methods for implementation and estimate of cost savings will be defined.INTRODUCTION Ventilation of underground workings remains a significant operating cost burden for modern mine operators. In particular, ventilation rates for underground diesel mining equipment are often defined by local regulatory bodies and are assumed to present minimal opportunity for optimization or savings, at least until battery propulsion systems can be adopted. Commonly, the quantity of air flow required is defined by the peak rated engine output power of diesel equipment. For example, Ontario Regulation 854 SS 183.1 (3) states that “The flow of air must be at least 0.06 cubic metres per second for each kilowatt of power of the diesel-powered equipment operating in the workplace”. Jurisdictions that define air flow using the prescribed CANMET or MSHA ratings use peak engine emissions to calculate air flow required for dilution ventilation. These approaches are similar in that the maximum power capability of a vehicle’s engine is used to define the ventilation rate in all areas where it travels, regardless of what power output is actually used in any of those areas. Examination of the duty cycle of a typical underground haul truck identifies a large variance in the power output of the vehicle depending on its location in the mine and the activities undertaken at these locations. For example, travel on a mining sub-level requires a fraction of the truck’s peak power due to the minimal grade and significantly reduced travel speed. So if we can reliably reduce the peak engine power capacity and engine emissions in areas where peak power is not required, we can logically cut the ventilation rates for those areas."

Jan 1, 2017

By Christoph Müller

Information exchange for mine process optimization is essential. Today, modern mining equipment uses the IREDES standard to exchange production plans and reports for easy management and storage. To gain further benefits from process optimization, a mine wide access to real-time information is needed as e.g.: The current status of a machine, operational details etc. Presently, real-time data exchange systems are developed by machine producers. Each machine producer uses its own way of gathering, managing, and storing production data. These proprietary mining processes increase the complexity of cross platform data exchange and management for mines which involves machines produced by different vendors. Casting and unifying the data requires much effort. For this purpose, ?IREDES On-line? currently is being introduced. The standard defines an open, web based method for the exchange of volatile real time machine information. Two different principles are used: Web Services for cross platform information exchange within the IT world and the optional OPC UA for use with automation and process control systems. With such a standard information from machines of different vendors may be managed by using one common platform without spending the effort for dedicated interface development. Additionally, information management and storage will become straight forward since all the data are of the same format. The IREDES On-line standard utilizes the latest IT technologies as well as the knowledge and experiences gained from the previous IREDES standard. The paper explains the benefits, the use, as well as the technical design of the standard and gives application examples from the practice.

Oct 1, 2009

By D. L. Cramp

The Direct-Connected Electric Hoist In the latter part of 1931 a new electric hoist was installed at the Lake Shore mine. A number of interesting features were incorporated in this machine, which is the first direct-connected, direct-current-operated hoist to be placed in service in the Kirkland Lake district. Many factors requiring care and study enter into the selection of hoisting-engine drive. In this instance, conditions warranted the selection of the generator voltage control system (Ward-Leonard), utilizing a direct-current driving motor and a separate motor generator unit. It was further deter-mined that additional economies could be secured by the selection of a motor generator unit with a flywheel, and consequently the Ilgner-Ward Leonard flywheel set was adopted. Some of the advantages of this system are: 1) Greater accuracy of control, resulting in increased flexibility in hand-ling with increased precision and safety; especially desirable in large, important installations where the rope-speed is high or where frequent shifting is necessary. (2) Reduced energy consumption. (3) Feasibility of load equalization, without which, in some cases, the power system would be unable to carry the fluctuating load imposed on it by the operation of the hoist. ( 4) Elimination of reduction gearing in the construction of the hoist. The hoist is located on the surface and is used for skip operation at the main shaft, hoisting ore from a present maximum depth of 4,200 feet.

Jan 1, 1933

Scope / Agenda ? What is Situation Awareness (SA)? ? Background on SA theory ? SA is critical in a wide variety of domains ? SA and human performance ? Consequences of poor SA ? Significant challenges for SA in mining operations ? Technology centric design ? SA-oriented design methodology ? Goal-Directed Task Analysis ? Design ? SA Measurement and Evaluation ? Applications of SA-oriented design

Aug 1, 2013

By Gavin C. Dirom

? The Mining Association of British Columbia (MABC) was established through an Act of Parliament in 1901 ? The MABC represents the interests of B.C.?s ? Coal and mineral mining companies ? Smelting companies ? Advanced stage development projects ? Key areas of work: ? Environment, Health and Safety ? Policy & Government Relations ? Knowledge and Information Services

May 1, 2008

By M. Palfreyman

"Most of the minerals employed in Canadian refractory production are imported; in fact, most of the refractories consumed in Canada are imported. Whereas this situation is partly due to a definite shortage of suitable raw materials, e.g., fire clays, it is possible that the potential of certain mineral deposits which could be usefully exploited has not been recognized. There are exceptions, notably magnesite and dolomite, from which refractories are produced in Canada.In many cases, known mineral deposits are located either in inaccessible areas or in areas where transportation would be a major economic factor. This paper lists some minerals and their respective known deposits which could be employed in the production of refractories, irrespective of economics."

Jan 1, 1973

Ontario Operaations Mining Garson Stobie Copper Cliff North Copper Cliff South Creighton Mcreedy East Milling Clarabelle Mill Smelting Smelter Matte Processing Anode Casting Refining Copper Cliff Nickel Refinery Port Colborne Cobalt Refinery

May 1, 2007

By Frederic M. Langevin

?? Introduction ?? LaRonde ?? History of Seismicity and Rockbursting ?? November 27th 2002 Rockburst ?? April 1st 2006 Rockburst ?? December 11th 2006 & January 11th 2007 Rockbursts ?? Seismic Risk Management Plan ?? Conclusions ?? Located in Northwestern Quebec (Can.) ?? In operation since 1988 ?? Reserves at Shafts #1 and #2 depleted ?? Production now comes entirely from Penna Shaft ?? Deepest single-lift shaft in the western hemisphere (2240 metres) ?? 7300+ tonnes per day ?? 2007 Reserves (proven & probable): ?? By-products: Ag, Cu, Zn ?? Sinking #4 Shaft (LaRonde II winze)

Feb 1, 2008

By C. J. Martin, M. P. Hay

"A methodology was developed in the mid-1980’s to predict plant performance from standard laboratory flotation tests. The technique is based on a simple, empirical kinetics model, and is tailored for use by the practical metallurgist.To date the performance of more than 20 flotation plants has been predicted, including copper, lead, zinc, phosphate, pyrite, graphite, cassiterite, platinum, nickel and various slags. The method has successfully been used to predict and size four flotation plants directly from bench-scale laboratory flotation testwork. All have since been commissioned, and have performed as predicted.The technique has now received broad acceptance within the South African mining industry, for example in the last year alone it has been used to drive flowsheet development for at least seven new plants. It is also being used to assist in the optimisation of existing operating plants.The methodology is described in this paper and verification of the methodology is presented using case studies of porphyry, polymetallic and PGM operations.INTRODUCTIONThere is considerable interest these days in the use of modelling to simulate flotation circuits, for process design and plant optimisation purposes. Although these models are proving to be useful tools for plant design and optimisation, their complexity can make them cumbersome – expensive to use and difficult for metallurgists to visualise and mentally absorb, without a background in each specific technique. In “SUPASIM” no attempt is made to measure flotation fundamentals, rather to use empirical relationships between laboratory flotation kinetics and plant performance – relationships that hold up well to validation exercises as will be demonstrated later in this paper. Although not designed to be as comprehensive as other models, “SUPASIM” is easily understood by the operating metallurgist and can be quickly and easily applied."

Jan 1, 2004

By Donald Carlisle

"IntroductionTHE OPINION is held by many persons outside the mining industry, and by some within it, that mine •operators customarily find it advantageous to mine •only the richer parts of orebodies and to leave behind, perhaps permanently, leaner material which could be mined only at a lesser profit. This opinion and the inference which might be drawn from it that 'gutting' of mineral resources is a common feruture• of the mining industry are prejudicial to the intertsts of the industry and deserve careful scrutiny. Oddly enough, a theory of mine economics which gives much support for the opinion was advanced first by members of the mining profession itself, has been repeated •several times in mining literature, and to my knowledge has never been adequately refoted.According to the theory, selective mining of the rich ore first on a large scale will yield substantial gains and these gains do not merely reflect the desire of 'money minded investors' for a quick return but derive from the logical application of compound interest rates and the concept of ;present value. W. O. Hotchkiss and R. D. Parks (1) illustrate the reasoning with a hypothetical example in which an orebody of 4,000,000 tons may be mined either in its entirety in forty years at $1.00 per ton profit or selectively with the recovery of only the richest half in twenty years at $1.50 per ton profit. They show that, with Hoskold rates of 4 and 8 per cent, the present value of profits from mining only the richer 2,000,000 tons exceeds the present value of profits :from mining the whole orebody by about 20 per cent."

Jan 1, 1953

By A Walker

The presence of high noise levels in many industries, together with the fact that countries are becoming increasingly concerned with the health of its citizens, has contributed to the importance of the problem of hearing loss. This problem has become the focus of scientific research, law and medicine, and the object of this thesis is to present the means whereby noise may be detected, with its resulting effects and possible means of control, in mining operations. 0BJECTIONABLE noise is a particularly prevalent by-product of the mining industry, and, al-though a dangerous noise level has been recognized, it is believed that at no time now, or in the future, will it be possible to enumerate a single over-all decibel figure at which hearing impairment will oc-cur. Individual susceptibility must be recognized in any study of occupational loss of hearing aimed at the setting of standards and criteria for industrial noise control.

Jan 1, 1963

By Gordon E. Agar, Brian Lyons, Gregory H. Styles, William B. Kipkie

"Rock rejection during the flotation of a copper-nickel ore was improved by adding carboxymethyl cellulose to both a rougher and cleaner flotation stage. The selection of the rock depressant was based on laboratory rates studies. Plant operating results are presented which confirm the laboratory selection of two particular brands of carboxymethyl cellulose.The rock assay of the concentrate was reduced from more than 40% to less than 15%.IntroductionThe traditional method of selecting flotation reagents relied upon batch bench scale tests, conducted under arbitrary conditions, to identify the effect of the reagent under examination. Too often these were ""one-off"" tests with little or no regard paid to the reproducibility of the results. Sophisticated researchers used statistical methods to design and evaluate the experiments but they were still obliged to rely on the arbitrary and often unreliable batch tests to generate the numbers that were analyzed statistically. An interesting side-effect of the enhanced sophistication of the statistical analysis was often that no significant effects would be uncovered in a series of experiments that would have generated many positive conclusions and much further experimentation if the same results had been evaluated by the traditional method.In the recent past, at least two groups of researchers a have directed their attention to the reliability of the batch experiments with a view toward improving the reproducibility of the test data. In this work the best of the improvements advocated by both of these groups have been adopted in order to generate kinetic data from batch tests that are as reproducible as possible.The objective of the work was to reduce the rock content of a bulk sulphide concentrate produced at Inco's Shebandowan mill. During 1982 the Shebandowan concentrate analyzed 3.5% Cu, 7.4010 Ni, 25% pyrrhotite and more than 40% rock, which resulted in an MgO content of 10.4%. Besides the expense of shipping all of this rock to Sudbury, the rock also contributed to the poor filterability of the concentrate. On favourable occasions the moisture content of the filter cake was slightly over 20% by weight. The magnesia content of the concentrate was deleterious to the reverberatory furnaces used by Inco for smelting nickel concentrate because the slag viscosity increased as the magnesia content increased, and the nickel lost in the slag went up."

Jan 1, 1987

By M. Savella

The Runruno Gold Project is located on the island of Luzon, approximately 200 km north of Manilla in the Philippines. The mine is a surface mine operation and use the proven BIOX® and carbon in leach processes to recover gold, and the ASTER™ process for detoxification of the CIL residue prior to discharge to the Residue Storage Impoundment (RSI). Work to date has defined a mineral resource of 1.39 million ounces of gold, and the operation will produce 96,700 ounces of gold per annum over a mine life of 10.4 years. The BIOX® circuit is designed to treat 140,000 tpa of concentrate with a design capacity of 404 tpd of concentrate at a design sulphide sulphur grade of 17% S2-. The Runruno project is the first BIOX® plant to implement the Generation III BIOX® design principles. As part of the Generation III BIOX® program Outotec supplied a turnkey, containerised metallurgical laboratory to facilitate the first four stages of the BIOX® and ASTER™ inoculum build up requirements. BIOX® inoculum build-up was started during early January 2015 with 5 litres of stock cultures shipped from South Africa. The BIOX® culture was successfully adapted to concentrate produced from the mini plant during March 2015. The ASTER™ inoculum build-up commenced during early August 2015 utilising 27 litres of ASTER™ bacterial inoculum already adapted to similar process conditions expected during commercial operation. This paper will detail the various stages of inoculum build-up through to commissioning and ramp-up of the BIOX® and ASTER™ Processes at the Runruno Gold Project. The paper will highlight some of the factors affecting the commissioning process as well as the improvements seen through the introduction of the Generation III BIOX® design principles.

Jan 1, 2017

By J. Gebhardt, D. McBride, C. R. Bennett, Croft. N., M. Cross

A comprehensive model of solution flow through heap leach systems requires a numerical solution with the ability to predict variably saturated-unsaturated flow through porous media domains that contain materials with spatially variable properties. The types of flow associated with stockpile leach processes lead to flow problems, such as infiltration into dry soil, drainage, perched water tables and flow through heterogeneous materials. Computational methods for modelling this class of flow behaviour are conventionally based on the classical Richards' equation. However, the governing equations are highly non-linear, difficult to solve, and require iterative numerical solution methods. The pressure-based form of the Richards' equation suffers from poor mass balance, while the mixed form can possess convergence difficulties. An adaptive transformed mixed algorithm is described, which reduces the non-linearity of the problem, optimizes the time step size, and provides a fast, numerically robust scheme that significantly reduces computation (or CPU) time. This method is shown to give fast, accurate solutions on a number of complex flow problems. The utility of this algorithm is illustrated through its implementation within the PHYSICA computational modelling software, which incidentally, provides a framework for a comprehensive heap leach model.

Jan 1, 2005

By W. T. Gotheridge

The principal sources of coal-dust underground are, of course, coal, and the working of coal. Coal-dust is most dangerous when it is in the finest state of division. This class of dust is found mostly on the roads, being blown or shaken off the loaded trams in transit, or carried in suspension by air currents. The air current passing from the working faces may also carry dust in suspension into the return airway, and the air current from the surface may carry dust from the shakerscreens into the intake airways. The mosl dangerous dust we have to contend with is, (a) that which is most finely divided, and (b) that which contains the most volatile matter, including the inflammable occluded gases, and also oxygen absorbed from the air. According to experiments, coal-dust in a fine and dry state would intensify an explosion, in air free from fire-damp carrying in excess of 3 ozs. of fine dust or 6 ozs. of coarse dust per cubic yard. The volatile matter in the dust must be between 12 and 31 per cent. in the ash-free coal, the latter percentage giving the highest flame velocity. It is vary difficult to propagate flame where coal-dust contains a large percentage of stone-dust, (say 50 per cent.). Shale-dust or other incombustible dust containing no volatile hydro-carbons or carbonaceous matter will prevent the extension of an explosion if mixed with coal-dust in proportion of say 70 per cent., and if the dust is finely divided and dry.

Jan 1, 1924

By D. W. Hendriks, C. Daoust, K. V. Konigsmann

"The concentrator of Mattagami Lake Mines Limited commenced operation in 1963. It had been designed with instrumentation proven at that time. New control techniques were added in subsequent years.An on-stream X-ray analyser was installed in 1968. It provided circuit analyses for six years without the aid of a computer. In late 1974, control of the flotation circuit by computer was incorporated into the system. Flotation efficiency improved considerably, zinc"" recovery increased by one percentage point and concentrate grade by four-tenths of a percentage point. Reagent costs decreased modestly through reduction of copper sulphate consumption."

Jan 1, 1976

By C. Allen, V. Hensel, J. S. Stachulak

"Vale has been actively evaluating new technologies to curtail diesel emissions. This paper discusses the selection, installation, operation, and evaluation of the MANN+HUMMEL SMF®-AR diesel particulate filter system to reduce diesel particulate matter emissions in underground mines. The system uses a sintered metal filter element, an iron fuel-borne catalyst with an onboard dosing system, an electric heater that uses onboard power, and a sensor-based control unit. More than 6,000 h of testing demonstrated that the system represents a breakthrough in the successful control of soot emission from light-duty vehicles with differing soot emission levels, exhaust temperatures, and duty cycles.RÉSUMÉ La compagnie Vale évalue activement de nouvelles technologies pour réduire les émissions de diesel. Le présent article discute du choix, de l’installation, du fonctionnement et de l’évaluation du système MANN+HUMMEL SMFMD-AR de filtrage des particules de diesel pour réduire les émissions de particules de diesel dans les mines souterraines. Le système utilise un élément filtrant en métal fritté, un catalyseur à base de fer dans le carburant avec un système de dosage intégré, un élément de chauffage électrique qui utilise l’alimentation incorporée et une unité de contrôle avec un capteur. Plus de 6 000 heures d’essais ont démontré que le système représente une avancée pour réussir à contrôler les émissions de suie des véhicules légers avec différents niveaux d’émission de suie, différentes températures d’échappement et différents cycles opératoires."

Jan 1, 2015

By E. P. Wiechrnann, C. M. Castro, G. A. Vidal, F. A. Muñoz

Different authors and publications indicate that Optibar Segmented Intercell Bars cause a remarkable distortion in the distribution of the current in a cell group. However, these results were based in inaccurate computer based models and do not represent the technology. During the last trimester of 2010, a 92 cells circuit from Barrick Zaldívar EW plant was implemented with Optibar Segmented Intercell Bars. The technology was incorporated progressively without disrupting the plant production. Depending on operational conditions, this led to a 2 to 4% current efficiency increase and 3 to 5% specific energy consumption reduction. By October 2011, 40,000 tons of copper will be produced with the technology.

Jan 1, 2011

By Mark W. Booth

THE Dominion Steel and Coal Corporation, as a coal mining concern and as a steel industry, has much pumping to do, and the conditions are as varied as it is possible to make them. We are faced with handling large quantities of water at low heads, and small quantities of water at high heads. We have fresh water, we have salt water, and we have highly acidulous water (see Table II). Our pumping problems are concerned chiefly with mechanical reliability, continuous, reliable operation, first cost, and operating cost. The Corporation is actually expending more than 15 per cent of its power consumption at the mines in pumping water, and at the steel plant about 17 per cent; that is to say, 16 per cent of the Corporation's entire power consumption goes into pumping water ( see Table I). We are pumping out of the mines 2 ½ tons of water for every tan of coal that is produced. At the Steel Plant, we are pumping 188 tans of water for every ton of steel we produce. (See Tables III and IV). The mine is pumping at high heads, up to as high as 1,400 feet in one lift ; in the Steel Plant it is, fortunately, at lower heads, 250 feet or 110 lb. being the general maximum. It behooves us, therefore, to look into the question of efficiency. In whatever direction we can gain something, it will be worth while. The centrifugal pump is not an adaptable machine. That is, a pump designed for some particular location and purpose will not always work efficiently if installed in some other place and used for some other purpose. It must generally be designed for the particular job it has to do. Reciprocating pumps are not so sensitive. We have Cameron plunger pumps that can be set up almost anywhere in a mine and they will work, but for big jobs they are apt to be clumsy and the driving power becomes a factor- which is, in fact, the controlling factor in deciding the type of pump we use. One disadvantage of the a.c. induction motor, however, is that its speed cannot easily be controlled. At its rated speed and output, it is a highly efficient machine, but, with any change in these, its efficiency goes all to pieces.

Jan 1, 1944