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According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By CLARENCE WM. POY

THE most common difficulty faced by an engineer or mine operator when opening a new property in a new field is the lack of roads and of cheap transportation. This one item often swings the balance of success or failure in starting a project. In Alaska, as elsewhere, such problems are more or less serious. In the boom days around the Valdez district, as well as in other parts of this territory, freighting was accom¬plished by dog teams or horses, or even by men that were willing to put their shoulders into harness, because there were virtually no roads. More important, there was only one time when supplies could be transported, and that was when there was suffi¬cient snow on the ground following a heavy wind. Then, and only then, could one depend on the snow to support horses and sleighs, and be sure that the gulleys, streams, and crevices in the glaciers were filled with snow to avoid pitfalls. These methods were used when one had no roads, no streams in the summer to float a barge, or even a trail for a pack train. If the snow was deep and soft, trans

Jan 1, 1935

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Due to the difficulties of ventilating large opening stone mines, the effective dilution of diesel particulate matter and noxious gases has often been problematic. Since stone mines have large openings that develop low air resistances, and propeller fans are designed for low pressure-high volume applications, main mine propeller fans may be a feasible option for ventilating underground stone mines. This paper describes the results of a case study where researchers from the National Institute for Occupational Safety and Health have demonstrated that significant increases in total mine airflow can be achieved and the ventilation improved in a large-opening stone mine by replacing an axial-vane mine fan with two 12-ft diameter propeller fans and adding a line of stoppings. In this study, the use of the propeller fans more than doubled the air quantity from 300,000 cfm to 750,000 cfm, while operating at 50 horsepower less than the original axial-vane fan.

By H. Richard Eisenbeis, Donna M. Watkins

Many technical professionals (tp)* desire to occupy upper level management positions. But career paths for most scientists and engineers do not extend beyond their specific disciplines. This is unfortunate. Our technical frontiers are expanding so rapdily that it is difficult, if not impossible, to make sound top management decisions without understanding the technical complexities involved. Technical professionals often are not considered for upper level management positions because they lack the managerial and interpersonal skills necessary to become successful administrators. You've heard this before, but a key component of these skills is the ability to communicate. Technical professionals are often unable to communicate as well as they should with nontechnical professionals and nonprofessionals within the organizations that employ them. Communication is important for managerial success Communication is the network of interactions whereby knowledge and understanding are conveyed from one social set to another (Flippo and Munsinger, 1982). In order to be successful, managers must not only be "good" communicators, they must be "effective" communicators as well. Good communication occurs when managers are able to formulate and transmit their messages in such a way that they are received and understood. Effective communication goes one step further: It occurs when recipients accept messages as legitimate and respond to these messages in the manner desired. Before promotion into upper level positions, managers must have developed organizational skills (planning, decision making, organizing, and controlling) and interpersonal skills (directing, influencing, and motivating). Applying these skills effectively is difficult without a highly refined ability to communicate. Effective communication, then, is basic to managerial success. Nowhere, perhaps, has the importance of being able to communicate effectively been emphasized more than in Mintzberg's landmark study of managerial roles (Mintzberg, 1973). Mintzberg's results indicate that executives typically averaged 36 written and 16 verbal contacts a day. These contacts were both important and trivial. They generally occurred in a random manner. Time spent on each varied. Scheduled meetings averaged over an hour. Desk work, telephone calls, and unscheduled meetings required an average of 15 minutes or less. Why technical professionals have difficulty communicating Three reasons why technical professionals do not communicate well are: • The work motivational patterns and personal attitudes of technical professionals are not conducive to effective communication. • Students in technical professions are not encouraged by educational institutions to develop their communication skills. • Organizations do not insist that all technical professionals be able to communicate in the language of business. The work motivational patterns of most technical professionals are indicative of internals and high achievers (Hunt, Salisbury, and Whittington, 1968). As internals, they believe they control their own destinies. As high achievers, they believe that task accomplishment is a primary indicator of success. To ensure a task is completed in the manner desired, tp's attempt to structure and define work situations so they alone are responsible for results. TPs consider the task accomplished when they, and perhaps other tp's, are satisfied with the results. From the tp's perspective, the task may have been completed. From a communication standpoint, two other factors may apply. First, solving the problem required very little interaction (and thus, communication) with others. Second, the tp's, considering the task accomplished, have little concern for how their "technical" answers will be translated to nontechnical persons needing

Jan 8, 1987

Organization Place Date 1919 National Drainage Congress St. Louis, Mo. Nov. 11-13 American Mining Congress St. Louis, Mo. Nov. 1.7-21 Canadian Mining Institute Vancouver, B. C. Nov.. 26-28 American Society of Mechanical Engineers:.... New York, N. Y. Dec. 2-5 American Institute of Chemical Engineers Savannah, Ga. Dec. 3-6 Geological Society of America...; Boston, Mass. Dec. 29-31. American Society of Heating and Ventilating 1920 Engineers New York, N. Y. Jan. Mining and Metallurgical Society of America ... New York, N. Y. Jan. 13. American Institute of Min. and Met. Engineers... New York, N. Y. Feb. 16-19 American Ceramic Society Philadelphia, Pa. Feb. 23-26

Jan 11, 1919

By M. I. Brasileiro

The use of experimental design to the study of mixtures has found a wide range of applications, even in laboratory scale or in industrial development works. The aim of this work was to maximize granite sawing waste content in ceramic tiles using experimental design. Based on the raw materials, specific formulations were developed using the experimental design. The raw materials were mixed and sample bodies were produced using uniaxial pressing. The sample bodies were fired and characterized in terms of water absorption, mechanical strength and X-ray diffraction. Regression models were adjusted relating the water absorption and mechanical strength with the amount of raw materials. The results showed that the methodology of experimental design maximize the content of wastes incorporated in ceramic tiles formulations. Formulations containing up to 40% of waste can be used for the production of ceramic tiles.

Jan 1, 2009

By Jean Cayouette

"In 1995, Louvicourt Mine started one of the first paste backfill operations in Canada. From 500,000 tonnes in 1995, the annual paste backfill tonnage produced reached 800,000 tonnes in 1999. The maximum throughput of the surface plant (including binders) is 3,50Ot/d with a final density of 75 to 76% solids which gives a slump of 15 to 17cm. Following the start-up of the paste backfill plant, the backfill strength performance levels were well below the pilot plant’s predictions. The introduction of ferrous slag, laboratory tests on various binder ratios with or without additives, and the desliming of the tailings enabled us to optimize the mix and operation costs. Primary and secondary stopes are filled respectively with a paste containing 4.5% and 2% binders consisting of a mixture of 20% cement and 80% ferrous slag. In certain stopes, the binder ratio may vary from 2 to 7%, but always in a ratio of 80/20. Six years after start-up, or 4.5mt of paste backfill later, this paper discusses the present operation and the major changes that have occurred over the years to optimize both the operation and the paste fill quality.INTRODUCTIONLouvicourt Mine is operated by Aur Resources Inc. which owns 30% of the shares. Its partners are Novicourt Inc. (45%, subsidiary of Noranda Inc.) and Teck Corporation (25%). The mine is located in the north-west part of Quebec, about 600 km north of Montreal and about 25 km east of Val d’Or. The mine commenced commercial production in July 1994."

Jan 1, 2002

By B. Haimson

A new loading apparatus was fabricated and used to conduct true-triaxial compression tests on KTB amphibolite, a crystalline basement rock. Tests in dry jacketed samples reveal that the intermediate principal stress has a significant effect on the onset of dilatancy and on rock strength, contrary to the implicit assumption made by Mohr-type failure criteria. Failure is induced through a shear fracture that dips steeply in the direction of the least principal stress. Experimental results lead to a new generalized strength criterion in terms of all three principal stresses. Unjacketed KTB amphibolite specimens, exposed to confining fluid, are considerably weaker than the jacketed ones, despite the negligible porosity and permeability. Failure is facilitated by several closely spaced subparallel tensile cracks normal to the least stress direction. SEM analysis suggests that microcracks developed upon dilatancy onset are penetrated and extended by the confining fluid, bringing about the unexpected rock failure mechanism at reduced stress levels. Un nouveau dispositif à chargement fut fabriqué et utilisé afin de réaliser un vrai essai de compression tri-axial sur KTB amphibolite, une roche cristalline du sous-sol. Les essais effectués sur échantillons enveloppés et secs révèlent que les contraintes principales intermédiaires affectent considérablement le début de la dilatance et la résistance de la roche, contrairement à la supposition fondée sur le critère de rupture de Mohr. La rupture est produite grâce à une cassure de cisaillement très incliner en direction où la contrainte principale est moindre. Ces résultats expérimentaux indiquent un nouveau critère de rupture général en fonction des trois contraintes principales. Les échantillons de KTB amphibolites sans enveloppe, exposés à un liquide confiné, sont considérablement plus faibles que ceux enveloppés, malgré la porosité et la perméabilité négligeable. La rupture est facilitée par plusieurs fissures de traction adjacentes et sub-parallèles, normales à la plus petite contrainte principale. L’analyse SEM suggère que les micro-fissures développent suivant le début de la dilatance, elles sont pénétrées et agrandies par le liquide confiné, produisant un mécanisme de rupture de roche inattendu, ceci à un niveau de contrainte réduit. Ein neuer Ladungsapparat wurde hergestellt um real - triaxiale Druckfestigkeitsversuche in KTB Amphibolit, einem kristallinen Grundgebirgsgestein, durchzuführen. Messungen in trockenen, bedeckten Proben zeigen that die mittlere Hauptspannung eine bedeutende Wirkung auf das Einsetzen von Dilatanz und auf die Stärke des Gesteins hat, im Gegensatz zu der impliciten Annahme auf Grund von Mohr-ähnlichen Versagungskriterien. Versagen ist induziert durch eine Scherfraktur die sich steil in die Richtung der geringsten Haupspannung nach unten senkt. Messergebnisse führen zu einem neuen, verallgemeinerten Stärke Kriterium dass auf alle drei Hauptspannungen basiert ist. Unbedeckte KTB Amphibolit Proben, die unmittelbar den umgebenden Fluiden ausgesetzt sind, sind wesentlich schwächer als bedeckte, trotz geringfügiger Permeabilität und Porosität. Versagen wird gefördert durch mehrere, nebeneinander liegende, sub-parallele Spannungsbrüche, normal zu der geringsten Spannungsrichtung. SEM Analyse lässt vermuten dass Mikrobrüche, die sich beim Überschreiten der Dilatanzschwelle entwickeln, durch die umgebenden Fluiden fortgepflanzt und weiter verbreitet werden, und unerwartet, auf Grund der reduzierten Spannungswerte, den Versagungsmechanismus des Gesteins einleiten

Jan 1, 2003

By W. J. Wright

Summary This paper describes the general situation of the mining industry in New Brunswick, and gives a detailed description of the recent developments in the antimony deposits at Lake George and the copper deposits in the vicinity of New Horton. At the end are lists of the most interesting geological literature relating to the Province and of the geological and topographic maps that have been published. Introduction In presenting this paper to the Institute, I apologize for the small amount of scientific data which it contains. Recent investigations in the Province of New Brunswick have been carried on largely by outside interests, and at present we ourselves are in the position .of taking stock. However, I am glad of the opportunity of giving you a general idea of the situation. The Province is making an honest effort to learn the truth concerning her mineral deposits and in time hopes to collect data which should be of interest to the mining community.

Jan 1, 1931

By J. G. Haymes

This report by the Bureau of Mines is the first of two proposed papers on evaluation of spectrophotometric, spectrographic, polarographic, and other analytical methods for quantitatively determining impurities in high-purity tungsten. Some of the methods described are standard methods that have been successfully applied to determine low-level impurities, several are modifications of known methods, and some procedures are entirely original. The Bureau of Mines is actively engaged in tungsten research because tungsten has an extremely high melting point, in fact the highest of any known metal. The metallurgist must know the content of impurities in tungsten because of the marked effects even micro amounts of impurity elements have on its physical properties. The Bureau procured a number of analyzed samples of above-average purity from research laboratories of companies engaged in production and fabrication of tungsten. These samples were investigated by the analytical procedures of those companies for several metallic impurities. Subsequent analytical laboratory determination of impurities in these samples agreed with the analyses as reported. With this assurance that analytical methods were basically accurate for metallic impurities, procedures for the determination of several of these elements were modified to lower the limits of detection and increase the sensitivity of methods. Carbon and the gases hydrogen, nitrogen, and oxygen were determined by standard instrumental methods, modified to provide greater sensitivity for reliable determinations when content of these elements was low. After the reliability of the modified procedures was affirmed, they were used as a product evaluation guide in the development of a vapor-plating technique for the production of high-purity tungsten. The following list of elements can be determined by one or more of these methods: AI, B, Be, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, S1, Sn, Ti, V, and Zn. In addition, a vacuum-fusion method for the determination of H, N, and 0, and a conductometric method for carbon are described. Lower limits of determination and detection for each element listed are given.

Jan 1, 1962

By J. Brian Anderson

Jointed micropiles were investigated to support bridge foundations where shallow rock was present. In this application, micropiles would have some amount of unsupported length, and would be subject to nominal lateral loads. Five lateral load tests were conducted on micropiles to demonstrate the impact of casing joints and rock socket embedment on lateral behavior. Load tests were simulated with FB-Multipier, a hybrid-finite element program for analysis of deep foundations, for proper design of the loading apparatus and instrumentation. The micropile sections were 2 m (6.56 ft) long, 273 mm (10.75 in) in diameter, 13 mm (0.5 in) thick walled, with a 50-mm (2-in) long threaded joint. Micropiles were made of one to three casing sections and were embedded 0.3, 0.6, 1.5, or 3.0 m (1, 2, 5, or 10 ft) into rock. In each test, two identical micropiles were pulled together using a simple frame until the weaker pile failed. All micropiles were instrumented with inclinometer casings while two contained strain gages at 0.76 m (2.5 ft) intervals. Load and displacement were measured at the pile heads. Tests showed the embedment of 0.6 m, 1.5 m, and 3.0 m (2 ft, 5 ft and 10 ft) sufficiently carried lateral loads over 180 kN (20 tons). The piles embedded 0.3 m (1 ft) were not able to maintain lateral load. In general, all micropiles tested to failure exhibited a brittle failure mode where there is small lateral deflection followed by a sudden failure at the casing joint. This was demonstrated in three of the load tests. In most cases, the micropiles were stiffer and stronger in the load tests than originally predicted numerically. The final test, where piles were not loaded to failure, verified that embedding vibrating wire rebar strain meters in the grout captured the bending moment profile of the micropile. The results showed the maximum moment in this case being carried directly across the threaded joint as predicted by the preliminary models. The results of these tests were used to calibrate the FB-Multipier numerical model. Using a load test that included bending strain measurements for a match, the soil properties were adjusted to produce reasonable matches for all of the load tests.

Jan 1, 2011

By R. M. Goktan

Point-attack picks are one of the most widely used tools for the mechanical excavation of rock and coal. In the literature, some practical formulas have been developed to estimate their performances under varying cutting conditions such as the pick geometry, cutting depth and cutting geometry. In this study, it is shown that Evans?s theoretical model, the most cited in the literature, has serious limitations concerning the changes in the cutting geometry. Analysis of the two independent full-scale linear rock cutting experimental data reveals that both his theory and its recent modification can not fully explain the mechanism of rock breakage under asymmetrical attack. The cutting force predictions made by employing such models are shown to be too significantly weak to be of any service in practice. In this study, a semi-empirical approach was followed by means of which cutting forces under varying cutting geometries could be made. By analysing the full-scale rock cutting test data, prediction equations of the peak cutting force and mean cutting force have been developed. Comparisons of laboratory determined and predicted force values indicate that the suggested prediction equations are applicable to quite different rock materialsm which have uniaxial compressive strength in the range of about 30?170MPa, and valid for different cutting geometries. It is also shown by regression analysis that the established prediction equations are statistically significant.

Jan 1, 2005

By Mustapha A. Raji, Alafara A. Baba, Christianah O. Adeyemi, Aishat Y. Abdulkareem, Rafiu B. Bale, Malay K. Ghosh

The increasing demand for pure aluminum and aluminum compounds of industrial quality from kaolinite ore cannot be overemphasized. Nigeria is one of the African countries endowed with abundant solid mineral resources that have not been sufficiently exploited to assist its indigenous industries. A wide array of applications of pure aluminum and its compounds are available, such as paper filling, refractories, adsorbent, catalysis, and paint additives. In this study, the upgrading of a Nigerian biotite-rich kaolinite ore by a hydrometallurgical route was investigated in oxalic acid media. During leaching studies, the effects of parameters including reaction temperature, lixiviant concentration and particle size on the extent of ore dissolution were examined. At optimal conditions (1.0 mol/L C2H2O4, 75 °C), 92.0% of the initial 10 g/L ore was reacted within 120 min. The dissolution curves from the shrinking core model were analyzed and found to conform to the assumption of surface diffusion reaction, and the calculated activation energy of 33.2 kJ/mol supported the proposed model. The unreacted product (~8.0%) analyzed by XRD was found to contain siliceous impurities and could serve as a valuable by-product for certain industries.

By Mustapha A. Raji, Alafara A. Baba, Christianah O. Adeyemi, Aishat Y. Abdulkareem, Rafiu B. Bale, Malay K. Ghosh

The increasing demand for pure aluminum and aluminum compounds of industrial quality from kaolinite ore cannot be overemphasized. Nigeria is one of the African countries endowed with abundant solid mineral resources that have not been sufficiently exploited to assist its indigenous industries. A wide array of applications of pure aluminum and its compounds are available, such as paper filling, refractories, adsorbent, catalysis, and paint additives. In this study, the upgrading of a Nigerian biotite-rich kaolinite ore by a hydrometallurgical route was investigated in oxalic acid media. During leaching studies, the effects of parameters including reaction temperature, lixiviant concentration and particle size on the extent of ore dissolution were examined. At optimal conditions (1.0 mol/L C2H2O4, 75 °C), 92.0% of the initial 10 g/L ore was reacted within 120 min. The dissolution curves from the shrinking core model were analyzed and found to conform to the assumption of surface diffusion reaction, and the calculated activation energy of 33.2 kJ/mol supported the proposed model. The unreacted product (~8.0%) analyzed by XRD was found to contain siliceous impurities and could serve as a valuable by-product for certain industries.

By Dan A. Brown

The following paper was written by Dr. Dan A. Brown, P.E. Brown is an Associate Professor at Auburn University's Department of Civil Engineering. The paper was originally presented at a FHWA's Transportation Research Board meeting and is presented here with the author's consent. Construction and design of drilled shaft foundations in hard pinnacle limestone requires flexibility from all parties involved due to the variability of the subsurface conditions. This article describes some strategies which have been found useful in the Birmingham, Alabama area. The importance of well trained and experienced field personnel in these conditions is noted. It is also vital that engineers understand the construction challenges so as to provide both quality assurance and cost effectiveness in design and in the specifications.

Jan 1, 1991

Process Simulation and Plant Design of a Mineral Selective Magnetising Flash Roasting Plant Using Neutrons

Sep 13, 2010

By Andrea McGlynn

Iron Ore Company of Canada, Labrador City 2011?Canada's largest iron ore producer, leading global supplier of iron ore pellets and concentrates ?Rio Tinto (58.7%), Mitsubishi Corporation (26.2%), Labrador Iron Ore Royalty Income Fund (15.1%)

May 1, 2011

By F. N. Kissell, C. M. McCulloch, Maurice Deul, J. R. Levine

The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and desorbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.

Jan 1, 1975

By Ann Barron

For millions of people, cold weather is a fact of line – and one that can make a major challenge out of just getting to work. But for those working in the blasting industry, a number of obstacles are created when old man winter blows in. In addition to the obvious concerns regarding personal protection, Mother Nature can throw some very nasty weather at the blasting crew trying to travel with explosives products from the magazine site to the job site. As such, divers need to be familiar with cold, ice, and snow driving conditions both on and off the blast site. It’s critical to know what to expect before you leave. Keep informed of the latest weather and road conditions as they change often; it will help you make the right choice in clothing and driving habits. Remember bridges and overpasses will freeze first even in temperatures above or near the freezing mark due to the effects of wind chill. Plan to take extra time to and from the job site.

Jan 1, 2004

By Mark R. Svinkin

Construction vibrations may be harmful to adjacent and remote structures, sensitive instruments and people. Construction vibration sources have a wide range of energy, displacement, velocity and acceleration transmitted on the ground. Effects of different dynamic sources and soil conditions on construction vibrations is analyzed. Consequences of construction vibrations are developed in various ways. It is important to assess intolerable vibrations before the beginning of construction activities. Guidelines for preconstruction survey are presented. Pre-construction survey and prediction of anticipated vibrations by IRFP method, monitoring and control of measured vibrations are important steps in preventing intolerable vibration effect.

Jan 1, 2000