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By M. Stelter

Since the first years in copper electrorefining natural products have been used as so called "additives" in the electrolyte. Glue as one of these additives offers a lot of different reactions with the metal ions and also with other additives like thiourea in the electrolyte. For a deep understanding of the effect of these additives it is important to know the routes of possible reactions in the electrolyte as well as the basics of electrocrystallization. Using this knowledge the interpretation of nodulation or inclusions of electrolyte in the cathodes in copper electrorefining is easier than before. Setting up on physical and chemical properties of the electrolyte and the additives practical investigations of the effects of additives in copper electrorefining and their impacts on copper crystallization and cathode quality are presented in this paper. Chemical deposition of glue against time and temperature are only few of the effects that are mainly caused by the use of natural products. In fact parameters like anodic and cathodic polarization are strongly affected by the additives as well as the effects of the additives are strongly affected by current density. This second part of the paper presents results concerning interactions of the above mentioned parameters.

Jan 1, 2007

By L. Byszynski

The results of a three month evaluation of the application of EMEW® technology at the KGHM Glogów II Smelter tank house bleed stream are presented. The current, conven¬tional electrolyte decopperization process has some limitations, including: only a fraction of its production is commercial grade cathode copper, significant operating costs, low current efficiency, low current densities resulting in low copper depletion rate, and arsine gas and sulphuric acid emission. The EMEW® cell technology developed by Electrometals Technologies Ltd. can overcome many of these limitations. Tests were performed on a pilot EMEW® installation comprising 30 cells at ambient temperature on electrolyte bleed, using current densities between 100 and 600 A/m2 , with copper concentrations between 45 and <1g/dm3. Results showed that a high grade copper can be obtained to the level of 7 g/dm3 of copper concentration in electrolyte. The use of EMEW® technology allows the direct and efficient recovery of over 85% of the copper contained in the bleed electrolyte. Glue & thiourea addition were tested in order to improve the parameters of the copper depletion process. The behavior of Arsenic and Bismuth was observed and a means for their elimination from the system proposed. On-line copper concentration monitoring is proposed to improve control and performance.

Jan 1, 2007

By J. L. Casado-Sánchez

Financial capital is highly volatile and if the investor does not get adequate compensation for the risk faced he may consider withdrawing his capital assets from the company and consequently produce a structural change in any sector of the economy. We study the variation in profitability of assets in terms of the changes that occur in the markets. The choice of models used is justified by the extensive theoretical and empirical use of them throughout the history of financial economics. We have used the capital asset pricing model (CAPM) and the model based on the arbitrage pricing theory (APT) to determine the beta value. These models have been applied to the monthly returns of 27 mining companies listed on the New York Stock Exchange (NYSE) or London Stock Exchange (LSE), using data from the period covered from January 2006 to December 2010. The results of time series and cross sectional regressions for CAPM and APT produce some errors, suggesting that many companies have failed to obtain an adequate cost of capital. Also the results show that higher risk firms tend to have lower profitability. These findings make it unlikely to be maintained over the long term the current status and could drive structural change in the mining sector in the form of mergers.

Aug 1, 2013

By B. Galy, L. Giraud

"This paper compares Canadian provincial mining safety regulations addressing hoist safety, automatic hoisting, and shaft obstruction. The regulations are quite similar among provinces, with only slight differences. Risk-mitigation strategies used in other industries are discussed, including their applicability to mine hoists. The specific case of software safety is introduced through examples. The mitigation of software failure is based on the use of the software lifecycle as recommended by the International Electrotechnical Commission (IEC) 61508 standard. Finally, ways to improve hoist safety are proposed.RÉSUMÉ Le présent article compare entre elles les diverses réglementations provinciales canadiennes concernant la sécurité des machines d'extraction, le levage automatisé et les obstructions dans les puits. Les réglementations sont assez semblables entre les provinces, mais elles comportent de légères différences. Les stratégies d’atténuation des risques utilisées dans d’autres industries sont abordées, incluant la possibilité de les appliquer aux treuils de mines. Le cas spécifique de sûreté des logiciels est abordé par des exemples. L’atténuation de la défaillance des logiciels est basée sur l’utilisation du cycle de vie du logiciel, comme cela est recommandé par la norme 61508 de la Commission électrotechnique internationale (CEI). Des moyens d’améliorer la sécurité des treuils sont également proposés."

Jan 1, 2016

By Garston Blackwell

Abstract - During geostatistical estimation of block grades, the kriging process produces a measure of error, the kriging variance or the kriging standard deviation. Estimation of the block error depends on the semi-variogram model for a deposit, which reflects fundamental characteristics of a deposit such as (1) nugget effect, (2) range of influence of grades, (3) different local spreads of data as a function of average grade (proportional effect), (4) nested structures, and (5) underlying anisotropies in the data; this model may be affected by sampling or assaying limitations, however. Because the kriging error incorporates so many features of both the deposit and data to be used for estimation, it may offer a substantial improvement on block classification over traditional procedures such as data density. Practice indicates that the relative kriging standard deviation (RKSD) is particularly useful for block classification in measured, indicated and inferred categories. Plots of RKSD in plan and section also can be used to demonstrate where extra drilling and sampling would be most advantageous for upgrading the class of some blocks. Moreover, the use of grade and RKSD filters can show where material near cut-off grade is poorly defined, indicating sampling target areas to improve block classification in the vicinity of the ore-waste boundary.

Jan 1, 1998

By J. H. Pateson, D. C. Comrie, D. J. Ritcey

"Geopolymers are inorganic semi-amorphous three dimensional silico-aluminates of the poly(sialate) type (-Si-O-Al-0-) or of the poly(sialate-siloxo) type (-Si-O-Al-O-Si-0-). Polycondensation occurs at low temperatures with geopolymers being stable up to 12oo0 c. Research, development and application technology pertaining to geopolymers is being undertaken jointly with Dr. Joseph Davidovits of The Institute for Applied Archaeological Sciences of Florida, U.S.A. This joint focused upon the chemical Barry University in Miami Shores, research and development program has stabilization and solidification of various waste products through geopolymerization. Of particular interest is the geopolymerization of mine wastes including tailings and waste rock derived from the processing of base metals, precious metals, potash, coal and uranium deposits.INTRODUCTIOND. Comrie Consulting Ltd., in cooperation and technical liaison with CANMET, Ottawa has been testing the application of geopolymers to mining wastes. Corporate efforts to date have concentrated upon reactive acid tailings, principally from the abandoned Kam-Kotia Mine site, and dewatered paint waste sludges. Test work conducted to date has successfully yielded geopolymer treated materials and wastes with increased chemical and structural stability. Wastes containing heavy metals, cyanides, arsenic and sulphur dioxide have been successfully geopolymerized."

Jan 1, 1988

By Edouard Masengo

A long dyke will be constructed in a lake with rockfill placed by end dumping method. Its crest will be at elevation 521.5 m compared to the nominal lake level at 520 m. In the first portion, its height will vary from 1.5 m on a 35.1 m thick tailings layer to 18.3 m on about 0.5 m of tailings. In the second portion, the dyke will be built on native silty clay and will vary from 18.3 to 15.2 m in height. The tailings consist in stratified layers of fine-grained soils showing lateral and vertical segregation. The tailings are compressible and may develop excess pore water pressure on loading. The tailings overlie a thin layer of relatively soft native silty clay. The till beneath the silty clay is considered incompressible compared to the material above. After construction, as the tailings and silty clay consolidate, pore water pressures will dissipate and dyke stability will improve. Since dyke stability will increase with time, the primary concern is its stability during construction. As a result of construction activities, three potential modes of failure were identified and recommendations were provided regarding the measures that should be undertaken to increase dyke stability during construction.

May 1, 2003

By Engin Burak Anil

Objective, accurate, and fast assessment of damage to buildings after an earthquake is crucial for timely remediation of material losses and safety of occupants of buildings. Laser scanners are promising sensors for collecting geometrical data regarding the damaged states of buildings, as they are able to provide high coverage and accuracy at long ranges. Yet, we have limited knowledge on the performance of laser scanners for detecting earthquake damage, and requirements of such data collection. This paper focuses on characterizing the performance of laser scanners for detecting thin cracks for damage assessment of reinforced concrete frames. We identified a series of crack parameters based on the state-of-the-art damage assessment codes and standards. Similarly, we identified parameters, which affect the performance of laser scanners for detecting cracks, based on prior research in this area. We studied the width, depth, and orientation of cracks; sampling interval of the scanner, and the range of the laser beam from the surface. Effects of these parameters on the detection of the minimum crack size were determined in an experimental setting. An automated algorithm was used to analyze the data. The results show that it is possible to detect as small as ~1mm cracks.

Aug 1, 2013

By A. Dunnett, N. J. Turner, J. Koyanagi, M. Ji

The analysis of rare earth element (REE) samples is a necessary part of the metallurgical process for rare-earth bearing ores, providing invaluable information during testing procedures. This requires a fast, multi-element technique, capable of analyzing a variety of matrices for all rare earth elements. X-ray Fluorescence spectrometry and Instrumental Neutron Activation Analysis are typically used for high concentrations of REE, but they have limitations for some process work applications due to an inability to measure all elements, longer analysis times, significant interferences and elevated detection levels. The work reported here uses new approaches with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in order to achieve high precision and accuracy within acceptable timeframes. A combination of aerosol dilution and Kinetic Energy Discrimination (KED) produce a process solution assay method that is robust enough to deal with changing sample matrices and concentrations, whilst maintaining low reporting limits and precisions of less than 5% Relative Standard Deviation (RSD). For high concentration metallurgical and geological samples, a sodium peroxide fusion digestion procedure was used, followed by ICP-MS analysis using extended dynamic range (EDR) and KED. Using these technologies, it has been demonstrated that the necessary support can be given to metallurgical process work for REE extraction.

Jan 1, 2014

By Yi-xin Zhoa

The characteristics of coal bumps are analyzed based on the microseismic data from No.8935 workface in Xinzhouyao coal mine, Datong Mining Group. The geology of this workface is characterized by the thick sandstone roof and coal seam, both with relative higher stiffness and strength. In order to investigate the mechanism and precursors of coal bumps occurred in No.8935 workface, the locations of microseismic, the relationship of microseismic energy and frequency and the spectrum of microseismic signals are analyzed. The result shows that the coal bumps in No.8935 workface were mainly induced by the seismic caused by roof failure. The coal pillar near the goaf is more easily to bump. The statistics results indicate that the coal bumps were mainly occurred in the gate road near the pillar, less than 50m ahead of mining face and located in the hard roof adjacent with coal seam. Moreover, the frequency, energy, b-value and frequency spectrogram of microseismic events were found to decrease before coal bumps. It was found that the frequencies of the microseismic events before coal bumps mainly concentrate upon 5~60Hz. The sudden decreasing of frequency and increasing of amplitude of microseismic events can be regarded as a precursor of coal bumps.

Aug 1, 2013

By C. Bourgoin

"The limited development and application of new technologies to narrow-vein mining is currently impeding progress in the industry to a point where productivity, working conditions and operating costs have reached a critical stage in many Canadian mines.In an effort to foster the emergence and application of new technologies, Université Laval, together with other organizations, has carried out a R&D project focussed on the need of identifying new development pos5ibilities and of facilitating the transfer of technology in matters related to underground mining methods and machinery.The first phase of the study consisted of an in-depth assessment of current practices and problems in narrow-vein mining. The second phase was a state-of-the-art survey of mining methods and equipment, together with proposed modifications and innovations. The third phase of the project concerns the experimental development as well as the principal application of various proposed technologies.This paper presents an overview of the organizational, technical and strategic considerations which guided the University group and it serves as well to introduce a newly-published brochure, entitled ""Underground Mining Techniques of Vein Deposits"", which summarizes such work to date. More specifically, a perspective of technological developments applicable to narrow-vein mining is presented."

Jan 1, 1994

By Denilson Coutinho, Euler Soares, Paulo de Tarso, Jordana Ferreira, John R. Goode, Andreas Sprecher, Alexandre Rocha

The Serra Verde Project is located in the northern part of Goiás state, Brazil, and comprises 49 mineral claims covering an area of 69,814 ha. The Serra Verde deposit is a rare earth element (REE) enriched weathered granite comparable to the weathered granite, or ionic-clay, deposits found in southeastern China. The Mineral Reserves of the Serra Verde Project total 388 Mt (Measured and Indicated) at an average grade of 1,484 ppm of REE oxide (REO). Several hundred agitated leach and column leach tests have confirmed recovery of about 40 to 55% of the REE, except for Ce, using simple desorption techniques. Present plans call for a heap leach operation followed by precipitation of impurities and precipitation of a pure REE carbonate suitable for refining and separation. The project plan includes initial production of 5,000 t/a of REO, with a high content of heavy and critical REO, rising to 10,000 t/a of REO. This production rate will be obtained by mining of the Mineral Reserves over a 22-year mine life at an initial rate of 6 Mt/a for the first four years with the mining rate thereafter increasing as required by grade and production targets.

Jan 1, 2014

By Dwayne D. Tannant

The Fox Pit at EKATI Diamond Mine reached a depth of approximately 150 m as of September 2005. The pit is designed with 11 m wide benches excavated using a double benching technique leaving 30 m high bench faces. A series of blasting tests were conducted to improve catch bench reliability and increase the percentage of benches that meet an 11 m catch width. The design changes focussed on reducing damage to the bench crest because maintaining the bench crests is the most important factor in achieving good bench reliability. The most significant improvement was obtained by raising the bottoms of the lower trim blastholes by 0.5 m. This change decreases the depth of broken rock below the final bench elevation, and consequently reduces damage to rock that forms the bench crest below. Another improvement was the use of smaller diameter (165 mm vs. 270 mm) blastholes in the A and B rows for the upper trim blast. This change reduces the charge per delay during detonation, reduces the powder factor slightly, and reduces the energy affecting the final pit wall and crest. As mining and the blast testing progressed, the portion of the bench with crest achievements (>11 m) increased from 57% to 75%.

May 1, 2006

By Dirk Claessens

The term ?cost? is too small when describing the destructive power of safety incidents for mining companies. Breaches in employee or environmental safety are felt way beyond the bottom-line: human life can be taken; ecosystems tarnished; the ire of peoples, media and government inflamed; significant halting of production; and high levels of legal and financial challenges. According to a recent survey of Mining executivesi, ?ensuring workforce safety? was the most important issues identified above any other, with a plurality of 31 percent, reigning above capital projects, product efficiency, and equipment reliability. We accept that safety is a most paramount issue, yet for many reasons we keep approaching the problem the same way we have in the past. We need to stop doing the same things decade over decade and try something new. New innovations are significantly changing the fundamentals of how mining companies explore, excavate, produce, refine and distribute their valuable commodities. Technologies such as visualization, analytics, location awareness, and gaming simulation are making these enterprises smarter. Now, attention turns to an area we?ve long held as integral to our business: safety. By using the same breakthrough technologies that are changing our business, we can now boldly imagine ? and credibly strive for ? a world of zero incidents.

Aug 1, 2013

By Nick Vagenas

"Loading and transportation are important activities of the mining process. Automation of these activities in underground hard rock mining has been discussed for a long time. This paper deals with the performance evaluation of a prototype automatic Load-Haul-Dump (LHD) vehicle (a 7-ton GHH LF LHD model) operating in Zinkgruvan mine, Sweden. The purpose of the data analysis is to evaluate the operational and maintenance characteristics of the automatic LHD system in the mine. Graphical and numerical methods have been used for the statistical analysis of the data. IntroductionDuring the past years, the idea of integrated automation and tele-operation on Load-Haul-Dump (LHD) machines (Fig. 1) has attracted considerable interest in the Swedish mining industry. This is mainly due to the demand for improvement in the working environment and due to the rapid development of economic and reliable microprocessors for mining vehicles. Several advantages can be foreseen with the application of a Remote-controlled/Automatic LHD (RAL) system in underground mining. Some of them are (1)&apos;:• better utilization of working hours;• less interruption in production at shift changes;• better operational control of a fleet of vehicles;• improved safety; and• one operator may be able to operate more than one vehicle simultaneously."

Jan 1, 1993

By Robert B. Parsons

"No Canadian or his family is likely to escape the effects of proposals for pension reform tabled on October 9, 1986 by Finance Minster Michael Wilson. New tax rules are proposed for Registered Retirement Savings Plans (RRSPs), company pensions, and other forms of retirement plans. Draft legislation is expected to be released in the first half of 1987.IntroductionOver two years ago on February, 15, 1984, Mark Lalonde, then Finance Minister, tabled two White Papers. The first, Action Plan for Pension Reform, proposed improvements to the public pension system and increases in the minimum pension benefits standards to be mandated by the federal government. Since then changes have been made to the Old Age Security, Guaranteed Income Supplement and Canada Pension Plan programs. Also, benefits provided under pension plans subject to the federal Pension Benefits Standards Act have been improved significantly.The companion paper, Building Better Pensions f or Canadians, proposed to standardize and, in many cases, improve retirement savings through private plans by revising the tax rule s. The tax proposals in the Notice of Ways and Means released by Finance Minister Wilson on October 9. 1986 implement, with modifications, the tax treatment of retirement savings originally proposed in the May 1985 budget in response to that second paper."

Jan 1, 1987

By E. Contestabile, T. R. Craig

"This report describes the development and effective use of shaped charges as part of the Elliot Lake Mine Roof Stability Project to remotely remove the heads from roof bolts. With a slight modification, these same shaped charges are being recommended f or use to the Brunswick Mining and Smelting Corporation Limited (Mining Division), to cut steel cable bolts.IntroductionThe Canadian Explosives Research Laboratory (CERL) often receives requests to cooperate in solving problems encountered in private industry or other sectors of the government. CERL is equipped to design and test explosive and pyrotechnic devices and the policy is to treat each case individually.The first case reported evolved from a request from a sister laboratory at Elliot Lake. The intent was to remotely remove the head s of roof bolts as part of a mine roof stability project. The device designed for this use was 1000,70 effective in the laboratory and 80% effective in the mine.The second case reported results from a request from a private mining company knowledgeable of the Elliot Lake Project. Their requirement was to remotely cut cable bolts. This request was first treated as presenting a new problem. The solution, however, proved to be very similar to the former."

Jan 1, 1985

By A. Galibois, R. Singhal

"This paper highlights some of the potential application areas of knowledge-based systems in the mining industry. The basic theoretical principles associated with knowledge-based systems are discussed and the justification for mining applications is given. The paper concludes with a brief description of a prototype knowledge-based system applied to scraper selection that was developed at Université Laval on a LISP machine. IntroductionThe beginning of Artificial Intelligence coincided with the conception and development of the first computer systems some thirty years ago. At that time researchers were euphoric about the possibility of modelling the human reasoning process. Soon, however, they discovered that the combinatorial aspect of the set of possible solutions to a particular problem did not permit an in-depth evaluation.In the mid-60s researchers started to look at the heuristic approach because it was more suited to human behaviour with its congnitive abilities (i.e. representing, reasoning, problem solving and advising). The heuristic approach allows possible results rather than exact solutions and it is more rapid and cost effective than the exhaustive combinatorial analysis. The heuristic approach did allow some noticeable progress in the seventies with the development of the first expert system called MYCIN with the objective of diagnosing blood infection diseases."

Jan 1, 1988

By Elma van der Lingen

Gold is considered the most inert of all metallic elements, but the metal can show catalytic activity when prepared by specific techniques. Preparation techniques being used to prepare gold catalysts systems mainly involve precipitation methods incorporating gold compounds or complexes. This paper introduces a totally different method for the preparation of gold-based heterogeneous catalysts that can be used for oxidation and reduction reactions, as well as electrocatalysts. The method involves alloying of gold with a less noble metal, such as aluminium, to form a gold-containing intermetallic precursor. AuAl2 was produced by melting gold and aluminium together in a vacuum arc furnace under a protective atmosphere. The aluminium is then dissolved from the AuAl2 precursor by means of NaOH to produce a highly porous gold structure. The paper also reports on a method of incorporating transition metal oxide(s) with the porous gold to form an active heterogeneous catalyst. Promoter elements can also be melted with AuAl2 to improve catalytic activity. Alloying has the advantage that the promoter element can be in contact on atomic level with the gold. In-situ xray photoelectron spectroscopy (XPS) studies have also been done on the porous gold catalysts to further clarify the CO oxidation mechanism on gold-based catalysts.

Oct 1, 2003

By P. A. Geusebroek, N. A. Duke

Abstract - The Lupin mine, located in the central Slave province just east of the western boundary of Nunavut Territory, is a world-class example of a Neoarchean-aged banded iron formation (BIF)-hosted lode-gold deposit. At the minesite the gold-mineralized Lupin BIF, separating stratigraphically underlying psammitic wacke and overlying argillaceous turbidite sequences, delineates the Lupin dome, a hammerhead-shaped F2/F3 interference fold structure occurring at the greenschist to amphibolite facies metamorphic transition within the thermal aureole of the Contwoyto batholith. Detailed paragenetic relationships indicate that peak thermal metamorphism coincided with the switch from regional D2 compression to rapid D3 unroofing of the Neoarchean orogenic infrastructure. Gold initially precipitated with pyrrhotite, replacing amphibolitic BIF at the apex of the Lupin deformation zone, separating the east and west lobes of the Contwoyto batholith. Over the course of associated prograde/retrograde metasomatic overprints, gold was further remobilized during garnet and loellingite/arsenopyrite growth in chlorite-altered selvages of late-forming ladder quartz veins. A metamorphic model of ore genesis, with gold being scavenged and transported by metamorphic fluid that was shed and structurally trapped at the amphibolite recrystallization front, is favored over the previously proposed syngenetic and exogenic models of gold concentration that have tended to polarize genetic interpretations to date.

Jan 1, 2004