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By Gregory A. Johnson

Operations and Maintenance departments have long had an adversarial relationship. The widespread evolution and adoption of modern management techniques such as Reliability Centered Maintenance (RCM) and Lean Production however has driven interest in working co-operatively to optimize overall plant performance. Mining and minerals operations have long adopted RCM in maintenance, and are now adopting Lean throughout the organization. Modern management initiatives like these explicitly call for co-operation between the two disciplines of maintenance and production and many advances have been made in the realms of people and methodology. One area that has lagged behind in supporting these developments however is information systems. Enterprise Asset Management (EAM) systems in maintenance and newer Manufacturing Execution Systems (MES) in operations have not been truly integrated in the way needed. Complicated plants, different software architectures, continually changing conditions and many variables have lead to systems problems which have contributed to the maintenance/operations divide. Master data synchronization (the ?plant tree?) and integrated reporting of real-time data with transactional data are just two of the issues that are being solved by new approaches in information technology including web services and service orientated architectures. New technologies are coming on-stream to enable the final ?bridging of the gap?.

Feb 1, 2008

By Jozef F. Zurawski

River Des Peres Foul water Interceptor (Skinker–McCausland Tunnel) is a gravity sewer tunnel constructed to eliminate dry sewage overflows during high river stages and to improve the wastewater collection and treatment. The original 78-inch (2m)finished diameter Skinker-McCausland Tunnel started as a 21,500 feet (6.5km)interceptor with 13 work, drop and access shafts. The tunnel constructions included soft ground, mixed face and rock tunneling in karst formation with maximum overburden of 175 feet (53m). Due to the success of the project, the tunnel alignment was extended another13,361 feet (4.1 km) and 7 new structures by negotiating two additional segments with the contractor and the designers.

Jan 1, 2001

By Peter McDonald

In 1994 the world's largest underwater tunnel was constructed to link Canada and the U.S.A. This new tunnel was large enough to accommodate double-decker railway cars. The construction of an unplanned Retrieval Shaft was required to allow removal and servicing of the Cutterhead of the Tunnel Boring Machine before it passed under the St. Clair River. This paper, which is a revision of that published in Canadian Tunnelling, has been modified here to emphasize construction considerations and describes the evolution of the design and construction of this "Rescue Shaft" under extreme schedule pressure, and changed ground conditions..

Jan 1, 1997

By Belcher C. B

A procedure was required for the rapid determination of silicon in low-alloy irons and a suitable method used the formation and reduction of silicomolybdic acid at 50°C. The procedure gives results for elemental silicon and this enables the correct computation of oxidation requirements in basic oxygen steelmaking. The method could be useful in iron foundries which have not installed direct reading spectrometers.INTRODUCTIONOxygen steelmaking experiments required rapid determinations of 0,5-1,6 per cent silicon in iron (3-4 per cent C) within 10 min of sampling; a reproducibility better than ±0.03 per cent Si was desired. Only elemental silicon (Si°) is of interest as a fuel in basic oxygen steelmaking technology, and the proposed procedure determines exclusively this form of silicon. The method is described as it may prove useful to other workers although the interference study would be incomplete for some applications.The analysis of silicon in iron is frequently obtained using direct reading spectrometers, but for the proposed experiments the spectrometers could not be used because of the prohibitive distance from the furnace. It should be noted that spectrometers determine both the elemental silicon and that present as silicon dioxide in occluded slag and inclusions.The silicon content of iron and steel is determined in this laboratory by spectrophotometric measurement of a "molybdenum blue" colour. The reactions involved have been extensively investigated; Strickland (1952) showed that a...

Jan 1, 1965

Compagnie Miniere Esperance (CME), a mining company based in French Guyana, operates a gold primary ore body in open pit. The ore is processed through crushing, grinding and gravity separation. Tailings are stored in a ?fine? pond. Analyses of the fine ponds proved a residual gold grade sufficient for a chemical treatment. However, direct cyanidation would require a too large installation, regarding the local conditions (accessibility, supplying and rainforest meteorological conditions). It has been then decided to test the feasibility of a pre-concentration using flotation. Lab tests have been carried out by SGS Lakefield (Canada) in March 2007, which proves the technical feasibility. Therefore, CME asked Caspeo to: ? Carry out an on-site flotation pilot campaign. ? Design an industrial flotation circuit. The tailings reprocessing will contribute to a better tailings management and a dry up of the gold resource, limiting the risk of illegal mining after remediation of the CME site. CME MINE The Esperance gold mine is located in French Guyana, in the vicinity of several gold deposits as Omaï, Rosebel or Camp Caïman, holded by Iamgold and Newmont. These main gold deposits are located on the figure 1. Esperance was put into operation in the early 90?s. The first years were devoted to the mining of alluvial gold in the gravel of the Esperance Creek. Since then, operation was led in the primary gold deposit. Annual production is on average 254kg for a total production in fifteen years of 4300kg. Geology Esperance deposit is located in the greenstone belt of the Guyana Shield. Mineralization is in tectonic contact between sedimentary basin of Maroni and a granitic massif. Clastic series, composed of conglomerate and lamina sandstone, overlie a volcano-sedimentary basement (series called "Paramaca"). The area is strongly folded by shear movements, resulting from granite deposit. Gold is in interlacing quartz veins intersecting the clastic series. Gold is present in association with pyrite. Other elements, as silver or arsenic, are in negligible quantity. Exploitation The Maroni River is the only access to the Esperance mine. Only the saprolite and a part of the transition rock are extracted in the open pit. Excavation works are done using shovels Hyundai 450 (4 units) and haulage works using articulated dumpers Terex TA35 (4 units). These two sorts of equipments are presented figure 2. Mill The mill is composed of crushing and grinding processing plants. After gravity concentration, both plants produce tailings that are stored in two ponds: the first pond contains coarse product which segregates the particles crushed to 2mm upstream and settled clays downstream; the second pond contains the fine product made of particles ground to 200µm. These two ponds, bordered by dams and diversion canals, are located on former alluvial sites of Esperance Creek (see figure 3). [ ] The CME mill is currently producing gold concentrate, with a global recovery of about 67%. The ore is crushed by one jaw crusher and two hammer crushers. The ore then passes through a Knelson KC 48 gravity concentrator, producing a first gold concentrate. The

Jan 1, 2009

By P. S. Heyns, M. Heyns

A computer model has been developed of mine hoisting systems in deep South African gold mines. Particular attention was paid to the contribution of different modelling assumptions for the guides and guide-roller assemblies. Objective functions indicative of guide-roller tyre endurance, slipper-plate forces and perceived vibration levels were introduced to quantify dynamic performance. These objective functions were used to compare models. It was found that the choice of guide and guide-roller models did not influence the forces on the guide rollers significantly for typical shaft and conveyance characteristics at typical levels of viscous damping coefficients. The rigid and finite-element guide models gave the same results as those of the effective-stiffness guide model, and while the latter is suitable for simulation for design purposes, the finite-element model should be used for unusual guide geometries

Jun 19, 1905

By Stephen Gay, Dewetia Latti

"When improving a plant a mineral processing engineer would like to know the mineral composition distribution. In order to assess this distribution in particles, as compared to the corresponding distribution in particle sections, a procedure needs to be applied to the observed particle sections. Such a procedure is called a stereological correction. There exists many stereological correction procedures, but one group of such procedures is based on using those stereological equations that do not require making assumptions regarding particle shape or texture. These equations are called geometric probability equations.Davy derived a geometric probability equation to estimate the covariance of mineral composition distributions for particles from both particle sections and linear intercepts. This covariance can be used to measure the variance of the particle composition distribution of each mineral. The equation as presented by Davy requires textural information; however the equation was modified by Gay to be more directly applied to particle sections and linear intercepts. The variance obtained from applying this equation is fundamental to the binary stereological correction procedures developed by Gay and his colleagues; the covariance is fundamental to the multiphase stereological correction.Thus far, validation of both the binary and multiphase stereological correction has been achieved using numerical simulation. This paper shall present results comparing the covariance (and variance) estimates from Gay’s equation with actual three-dimensional information obtained from serially sectioning particles. This involved mounting a set of particles and continuously sectioning all particles uniformly so that the three dimensional structure of the particles could be obtained.The mineralogical data to which the equations described above were applied were derived from two individual size fractions from a hard-rock titanium deposit. The deposit contains a range of minerals and of mineral textures and the two size fractions selected were:"

Jan 1, 2003

By Anil K. Ray

This paper discusses in situ studies conducted at an Illinois Basin room-and-pillar coal mine to evaluate the performances of three different types of bolts under similar geologic conditions. The bolt types considered were the fully grouted passive rebar (FGPR), the resin-assisted mechanical anchor (RMAB), and the fully grouted tension rebar (FGTR). During the evaluations, the three types of bolts were installed in a single entry covering a span of three contiguous pillars with almost identical geologic conditions. The performances of the three types of bolts were investigated by instrumentting the bolts prior to installation as primary supports on cycle. Additional data on roof behavior was collected with extensometers and shear meters placed near the instrumented bolts. Excluding some time lapse right after installation, the performance evaluation of the three bolt systems was based on the data collected for over a year. Based on this study, it was found that the axial loads measured in the different bolt types did not show any identifiable patterns under the prevailing geological conditions at the mine. Therefore, the assumption that active bolts must be superior to passive ones is not always valid. Even though the studied mine did not have any thinly laminated, weak rocks in the immediate roof, the passive bolts performed as well as the active systems.

Jan 1, 2012

By J. N. Van der Merwe

The research described in the paper was aimed at providing standardized information of cases of failed and intact coal pillars in the form of databases to researchers. It also offered the opportunity to take stock of the pillar stability situation in coalmining and to review the impact of the application of the safety factor formula for pillar design. It was found that the physical parameters of coalmining have not changed substantially over the last four decades. However, changes in the controllable parameters like pillar width, pillar width-to-height ratio and percentage extraction have all moved toward the more conservative side. Scrutiny of the database indicates that of all the failures recorded, only 23 occurred in panels that were mined after 1969, when one can assume that the safety factor formula was fully applied. If the pre-1969 practices had been continued, at least 144 collapses would have been expected. There has thus been a substantial reduction of pillar collapse cases, justifying the cost paid for the formula, which has shown to be in the region of 600 million tons of coal. It is evident that that are distinct differences in the natures of the failures among different coalfields. This justifies the attempts to derive seam or coal field specific strength formulae and is a topic that should be pursued.

Jan 1, 2006

By Rob Farnfield

In the UK all new developments, including mines, quarries, tunnels, etc., are subject to a system of planning control. If the use of explosives is anticipated then such developments will attract a number of so-called ‘planning conditions’ relating to the blasting operation. This paper will outline a ‘typical’ set of conditions and how operators ‘plan to comply’. British Standards relating to both human and structural response are also reviewed and contrasted to the typical planning conditions previously outlined.

Jan 1, 2005

Objective The main purpose of this video is to teach mine rescue personnel certain aspects of rescue work that are not traditionally taught. These include the strain caused by working continually under adverse conditions; the "survivor guilt" that occurs from being spared the fate of one's deceased cohorts; and the posttraumatic stress that may be experienced during the sometimes lengthy task of recovering the victims' bodies. Background On November 20, 1968, an explosion rocked the Farmington No. 9 Mine in northern West Virginia (figure 1). The explosion killed 78 of 99 miners who were working in the mine, including all but one member of the mine's rescue team. Some 30 years after the event, researchers from the NIOSH Pittsburgh Research Laboratory (PRL) conducted a video interview with Danny Kuhn (figure 2), the only Farmington No. 9 mine rescue team member who was not working that day and who did not die in the explosion. According to the Mine Safety and Health Administration (MSHA), there are about 80 underground coal mine rescue teams in the United States, and according to the National Mining Association, there are more than 850 underground coal mines. This represents a significant decrease in both over the past decade. The low number of rescue teams is a concern because serious incidents, though fewer, still happen, and if a disaster occurs, there will be fewer rescue teams to respond. This would result in an increased need to use available human resources very efficiently. Much training to prepare these rescue teams still takes the form of what educators call "teaching to the test." In other words, teams practice in order to win mine rescue contests. This test-oriented approach has traditionally been augmented by interactions with others who have responded to real situations or by participating in actual incidents. Given few incidents and fewer rescue teams from whom to derive enrichment, the preparation of coal mine rescue personnel becomes a problem. Recently, more emphasis has been placed on active learning, such as working out problems in smoke. These sessions more nearly simulate the actual conditions that today's team members might rarely encounter. To properly prepare and retain the current coal mine rescue personnel who are left in the workforce, it is necessary not only to offer such hands-on experience, but also to replace the learning narratives that once were passed from team to team. The present video is intended to contribute in that capacity. Approach NIOSH researchers first learned of Mr. Kuhn in the fall of1998. Mr. Kuhn was contacted and agreed to an interview. An oral history interview was conducted with Mr. Kuhn in early November1998. After reviewing the videotape of the interview, researchers determined the content to be so rich as to warrant a second interview in a more formal setting. The second interview was done in early December 1998. During this interview, Mr. Kuhn spent about 2 hours describing the Farmington disaster, including the workplace climate leading up to the explosion, the events that took place in the 10 days after the explosion, and the nearly 10-year effort to safely and successfully recover most of the victims' bodies. The videotape of the second oral history interview with Danny Kuhn was reviewed and edited by NIOSH researchers for content. Careful attention was used to ensure that valuable information was presented, but within a reasonable timeframe. A detailed map of the Farmington No. 9 Mine was edited into the final video and used to highlight critical features as they were being described by Mr. Kuhn. Results and Accomplishments A 60-minute videotape and instructor's guide for use in safety training or other settings was completed. The target audience consists of all those who work in underground coal mines. This training video will help safety instructors better prepare mine rescue team members for the situations that they will encounter when engaging in extended rescue and recovery work. As a result of this expectations training, team members will be more likely to serve their

Mar 1, 2002

By Edmund J. Cardoza

WELCOME TO THE DEEP FOUNDATIONS INSTITUTE 26TH ANNUAL CONFERENCE AND WELCOME ESPECIALLY TO THIS SEMINAR ON NON-DESTRUCTIVE TESTING OF DRILLED SHAFTS, PRESENTED BY MEMBERS OF THE DFI DRILLED SHAFT COMMITTEE. MY NAME IS ED CARDOZA; I AM A VICE PRESIDENT WITH THE MILLGARD CORPORATION, A DRILLED SHAFT CONSTRUCTOR FOCUSING PRIMARLY IN THE EASTERN HALF OF THE UNITED STATES.

Jan 1, 2001

By Alain Langlais, Caroline Boudrias Chapleau, Claude Bazin, Ahmed Bouajila

"Slurry «viscosity» has been recognised for several decades as a variable that significantly influences the operation of grinding mills. This paper describes an instrument that can be used in a laboratory or a plant to measure and monitor the flow properties of mineral slurries. Laboratory results obtained for two different ore samples are consistent with results obtained during a full scale trial. The results provide a basis for analysing the effect of the solids concentration and particle size distribution on the slurry flow properties. Grinding tests were also conducted in an attempt to link the grinding efficiency to the rheological properties of mineral slurries.INTRODUCTIONThe flow properties, or incorrectly called «viscosity», of a slurry influence the operation of mineral processing devices. Work has been conducted for instance to assess the effect of this variable on the operation of hydrocyclones (Kawatra et al. 1996; Klimpel, 1982a) and dense media separators for coal (Napier-Munn, 1996). However, most of the research effort has been oriented toward the grinding processes which is still the most energy demanding operation for ore dressing (Fuerstenau et al., 1995).Results of investigations of the influence of slurry flow properties upon grinding performances are presented regularly in the literature since 1950. In the 70's, most of the research work was conducted with the aim of using slurry flow properties for the control of grinding mill and to analyze the effect of that variable upon the population balance model breakage and rate functions (Austin et al., 1984; Hemmings et Boyes, 1977). In the 80's, most of the litterature dealing with slurry rheology was devoted to the use of viscosity modifiers to adjust the slurry flow properties, allowing an increase of grinding mill throughputs (Klimpel, 1982b; Fuerstenau et al., 1985). Although laboratory and pilot plant results show the benefits of adding these modifiers to the slurry, few plants have published results concerning the advantages of such addition (Fuerstenau et al., 1985). It is felt that the use of these modifiers introduce operating difficulties with the concentration circuits, especially flotation (Kawatra et Eisele, 1988)."

Jan 1, 2003

By M. Clair Smith

This report is one of a series describing exploration, development, mining methods, and costs at United States open-pit mines; the Bureau of Mines prepares and publishes them in cooperation with the mining companies. Their purpose is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods and practices at various United States mines. The exploration, development, equipment, and mining of a large, oxidized-copper ore deposit by open-pit methods, the leaching of the ore with sulfuric acid solution, and the recovery of the copper as cement copper are described herein.

Jan 1, 1958

A field method combining solvent extraction and paper partition chromatography permits a simple and rapid semiquantitative estimation of gold in siliceous, argillaceous and sulphide ores. The method will facilitate the eyaluation of prospect samples in which the gold is too fine for separation by panning.Ethyl alcohol-hydrobromic acid mixtures are suitable for chromatographic development of the gold complex, and give clear reproducible definition of the gold zone. Substitution of commercial "methylated spirits" for the ethyl alcohol gives equally good definition, improving the potential of the method for field use.A batch of six samples in the range of 0·5 to 5·0 dwt/ton can be completed in two hours. The range may be extended by simple modification to higher or lower values.INTRODUCTIONIn a chromatographic method described previously (Lever 1958, Nevill and Lever 1959), gold from a standard volume of ore clamped between -plate glass was extracted by aqua regia on to the paper. After cautious drying the chromatogram was developed by an ethyl acetate-nitric acid-water mixture and gold was identified by spraying with stannous chloride solution. Sensitivity of the method in the low range was poor. The brown line obtained in the 1-3 dw/j ton range, caused by movement of gold in the reduced form, was not considered to be a satisfactory confirmation of the presence of gold. It was felt that the method would be improved by using a more elegant extraction and applying developing conditions which would produce a well defined purple line at all gold values. Iron was a limiting factor, and a method of eliminating its interference was needed.The method now developed overcomes these shortcomings, and gives a reliable result with a purple line for assay values of 0·5 dwtjton and over. Gold is dissolved from an...

Jan 1, 1964

The efficiency of water sprays in suppressing airborne colliery dust depends on many variable factors. A survey of previous work in this field shows that swirl spray nozzles are the best dust suppressors.Investigations carried out in an experimental dust chamber show that, in spite of limitations to the application of water sprays in underground use, promising dust suppression efficiencies in mechanised mining can be obtained with swirl spray nozzles.INTRODUCTIONA dust hazard has always been associated with coal mining, and the recent growth of mechanisation has resulted in a greater production of fine coal and dust, thus increasing the hazard. A better knowledge and appreciation of the medical aspects and dust explosion factors has led to practices reducing the seriousness of the problem. However, the dust hazard still exists and its control is basically an engineering problem.Dust, as with any atmospheric pollution, may be removed from the, mine by ventilation, which is an indirect method of control. Direct methods, in which the dust is prevented from being produced and from becoming airborne, should be employed where possible. Of these direct methods the most significant is the use of water sprays.THE DUST HAZARDAn appreciation of the physical nature of the more important dust hazards is necessary before considering the removal of the hazard. The main hazards associated with colliery dusts are the health hazard and the explosion hazard. "Dust" comprises solid particles of size minus 20 mesh Tyler (833 microns).

Jan 1, 1964

By M. A. Trevits

Mine seals are used in underground coal mines throughout the United States to isolate abandoned mining areas from the active mine workings. The objective of adding inert gas to a sealed mine area is to quickly reduce the oxygen concentration in the sealed area to a level that will not support combustion. In the US, this process is typically conducted from the ground surface and because surface-to-mine access is constrained by so many variables, it is very difficult to provide a source of inert gas to the place where it is needed underground. To alleviate this problem On Site Gas Systems, under a NIOSH contract, built a nitrogen (N2) generation plant that operates in the underground environment. The purpose of this work was to create a reliable in-mine mobile plant that would extract N2 gas from the mine atmosphere and use the gas to create and maintain a safe sealed mine area. The plant is based on a novel design using pressure swing adsorption technology and is sized to fit on a standard shield car or mine dolly for easy transport in and around an underground coal mine. The plant is capable of producing about 900 scf/min of N2 gas at ambient mine conditions. After an exhaustive series of laboratory tests, the plant was field tested at the NIOSH Safety Research Coal Mine (SRCM) where a portion of the mine was sealed and rendered inert. During the test, the movement of the injected gas was monitored at several underground points to observe the progress and extent of the inerting process. This paper describes the plant design and the results of the field test at the SRCM. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

By J. H. Van Reenen, H. Thiele, C. Bergman

For some time spirals have been the process equipment chosen to recover metal in the size range 0.15 to 3mm from ferrochrome and silico/ferro manganese slags. Recoveries of metal obtained using spirals are usually about 70%. Spirals are also difficult to control. By combining a novel gate on the Apic pneumatic fines jig with the recently developed Apic classifier, metal recoveries of 76% and grades of over 90% have been obtained for FeCr and SiMn slags in the size range 0.15 to 3 mm. The paper compares classifier operating performance and costs with those spirals for FeCr and SiMn metal recovery from slags. The classifier technology can also be applied to chromite and iron ores and coal fines.

Jan 1, 2004

Collaboration between education providers is the key to long-term sustainability and improved quality in mining education. The mining industry is now, more than ever, an industry doing business on a global basis. Staff are recruited by global mining companies in many different countries and can find themselves deployed anywhere in the world. The mining engineer of tomorrow must be willing to take on this international challenge, and must be educated to a level where he or she has a comprehensive grounding in technical aspects of mining engineering, but also a well-founded appreciation of management, social, environmental and cultural issues that may be encountered around the world. In order to deliver such an education, academic providers must collaborate at both a national and international level. This paper provides an overview of progress that has been made in Australia through the national joint venture ? Min¬ing Education Australia (MEA). Supported by the mining industry in Australia, through the Minerals Council of Australia (MCA), MEA has been operational since 2007 and is seeing the development of a range of innovative courses and delivery methods, together with a high level of staff cooperation across the country. MEA has also commenced some international teaching initiatives that are seen as a catalyst for a far greater degree of international collaboration in the future. Such activity is not only to the benefit of the students who are taught by experts from around the world, but it also ensures that individual univer¬sity programs remain viable in terms of staffing numbers and financial performance. The paper also presents some statistics on recent upward trends in mining engineering student numbers from around the world, in response to the global shortage of mining engineers.

Jan 2, 2010

The risk associated with mining induced seismicity is one of the major threats to the safety and sustainability of deep underground mines. This paper describes techniques that allow site practitioners to efficiently control such risks in mines. The proposed approaches rely on ground support to strategically control seismic risk and re-entry time to tactically control this risk. The strategic approach is based on the detailed understanding of past seismicity to as certain the seismic hazard of individual sources throughout the mine. This approach also relies on assessing the potential damage that these sources can induce on nearby excavations using the excavation vulnerability potential (EVP) and rockburst damage potential (RDP) concepts proposed by Heal et al. (2006). It is then possible to investigate how to reduce the risk of experiencing damaging seismicity in mine drives by locally enhancing the ground support system. The tactical approach relies on a proposed methodology to estimate reliable re-entry times or exclusion periods based on the seismic decay following blasting. Some examples of how these techniques have been applied in Australian mines are given.

Jan 1, 2009