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By Douglas Banks

Construction for the new 2.5 MGPD raw water intake project commenced December 2002. The project, initially designed as a 12' Ø concrete lined intake shaft,145' deep, with two offset 24" lake taps, 520' and 470' long was subsequently “value engineered” running the two lake taps through a single conduit. The offset for summer and winter pools was accomplished via a second shaft located at the lakes edge. Construction involved the use of blind drilling techniques for the shaft development and drill and blast techniques for the tunneling. All works were completed through extremely hard crystallized sandstone. The project came online August 12, 2004.

Jan 1, 2005

By J. -P. Saindon, L. D. Nel, A. E. Hall, S. G. Hardcastle

"This paper reports on an investigation into gas and dust concentrations in Ruttan Mine's exhaust air. The values obtained indicate that there is excellent potential to recirculate approximately 25% of the hot exhaust air into the intake air to reduce winter heating costs. Contaminant concentrations vary significantly during the course of the working shift and decrease in the mine exhaust system as the air returns to surface. A proposed on-line control system is outlined which would permit recirculation to be implemented with a pay-back period of less than two years. IntroductionIncreased energy costs and depressed mineral prices have resulted in mines, which use winter ventilation air heating, reviewing their systems to try to reduce costs. Heating costs can be significant, for example, Potash Corporation of Saskatchewan spends an average of $580,000 per mine per year and Ruttan mine spends approximately $IM per year on propane for its direct-fired heating system.Several method s of reducing heating costs have been considered and the following have potential application.Heat Exchange Between Exhaust andIntakeThis is usually accomplished by run-round glycol systems. The system is limited by ice formation on the coils in wet exhaust air and by the low exhaust air temperature, usually l0ºC. It also requires close proximity of the intake and exhaust airways to ma~e the cost of the connecting pipeline and pump systems economic . A feasibility study by Inco's Thompson operation reported that a proposed system of this type had a 19-year payback period and was, therefore, uneconomic. Potash Corporation of Saskatchewan is currently investigating plastic heat exchangers for a trial system because of corrosion on metal exchangers. It has the advantage of a 17°C exhaust temperature and relatively dry exhaust air.Waste Heat ReclamationThe waste heat from compressors and hoists can be used for heating in some mines. The feasibility of such a system depends on the individual layout and the proximity of the heat source to the inlet airway. Other mines have considered using the exhaust air in greenhouses to provide a cash crop."

Jan 1, 1988

By Robert Boyd

The Diamond Markets ? Supply has continuously increased over the past 25 years ? However, global supply is expected to drop by 1 to 2% by 2015 ? Demand Driven Market ?Demand is expected to grow 3% annually through to 2015 ? Supply Squeeze Anticipated (2010 to 2015) ? Consumption is exceeding rate of discovery, mine development and reserve replacement ? These fundamentals are driving increased capacity and production at existing mines in South Africa, Botswana and Russia and new areas such as Canada ? Canada is now the third largest diamond producing country in the world ? These fundamentals are also driving record levels of exploration expenditures throughout the world with particular focus on Africa and Canada

May 1, 2006

By Mukhopadhaya K. K, Cory A. H

The concept of using travelling magnetic fields created by linear motors was stimulated by Laithwaite who advanced ideas on motors with shaded poles (Laithwaite, 1968), rack and pinion motors (Laithwaite, 1970) as well as low speed, brushless motors and three dimensional motors (Laithwaite, 1973a and 1973b).Sudan (1963) and Sundberg (1969) had applied the concept to metallurgical processes. However, the use of travelling magnetic fields has not been used widely to produce conditions for the separation of magnetic from non-magnetic minera1s or even magnetic materials from non-magnetic materials, although some attempts were made by McCarthy (1922), Davis (1934), Dean, Gottschalk and Davis (1934) and Gottschalk (1934).Laithwaite (1973, a) while working with linear motors made suggestions for designing separators and in the work described here, the observations of Laithwaite and others are extended to determine the characteristics of the motor with a view to using it as a magnetic separator.

Jan 1, 1980

By W. Zheng

Pipelines can develop stress corrosion cracks in either intergranular or transgranular form. Since the mid-1980s, numerous colonies of transgranular cracks have been found across Canada and many other countries in the world. While the intergranular form of cracking has been well studied in the past 40 years, the mechanisms governing SCC in near-neutral pH environment, i.e., the transgranular form of the cracking, are yet to be understood in greater depth. Over the past ten years or so, a large number of research publications have been available on this subject and this paper summarize our latest progress in understanding the mechanistic aspect of the problem. Better understanding of the role of mill scale surface and the steel metallurgy in crack initiation has been indicated in the recent literature. However, the initiation of SCC in the lab research still relies on loading conditions that are far more aggressive than those encountered in the field. Most crack growth studies in the past are also performed under very aggressive mechanical conditions, which could have prevented the observation of environment effects. However, more recent research at lower K or Delta K ranges seems to suggest a strong role of the environment. Naturally, modeling of growth should reflect the effect of the environment, steel metallurgy, and the changing mechanical properties of the pipe steel with time. For a specific steel in a given environment, the crack growth rates tended to increase with the strain rate, indicated either by the nominal applied loading frequency or by the calculated crack tip opening rate. Future research needs to address the issue of concurrent growth of multiple interacting cracks. More attention should also be given to concurrent initiation of multiple cracks in a colony, as failure is usually caused by a coalesced crack not by an individual crack. The effect of soil environment should not be limited to the chemistry of soil solution; other factors such as cathodic processes, the variation of environment with time and physical conditions of coatings should also be considered as part of the study.

Jan 1, 2005

By T. J. Otto, C. H. Cloete, T. Mkhatshwa, T. J. van Heerden

The value realised by an open pit mine depends on the quality and integrity of the mine planning process as well as the level of execution against these mine plans. When managing the execution against the mine plan, how well the mine plan is executed spatially, is of critical importance. The short-term mine plan is the plan that is physically executed on most open pit mines. At the same time, the spatial mine-to-plan compliance is typically reconciled against the annual business plan. Short-term mine planning, therefore, plays an important role in the effectiveness of the spatial mine-to-plan compliance reconciliation process by providing operational teams with detailed designs and schedules, while ensuring that mining execution is spatially aligned with the business plan. The Sishen open pit iron ore mine (Sishen) strives to continuously improve spatial compliance to the business plan. Sishen enhanced the role that short-term mine planning plays in enabling the forward-looking component of the spatial mine-to-plan compliance reconciliation process. The enhanced short-term mine planning process focuses on detailed tactical sequence designs per mining pushback, the health of value chain buffers, spatial plan-to-plan reconciliation, and the associated management routines. This led to improved spatial mine-to-plan compliance to the business plan from 71% to 94% over the four-year period from 2020 to 2023 inclusive. These results indicate that the application of short-term mine planning as part of an integrated spatial mine-to-plan compliance process at open pit mines can contribute positively to improving the level of spatial execution against the business plan. This paper presents the enhancements made to the short-term mine planning process, which other open pit mining operations can consider to improve spatial mine-to-plan compliance.

May 27, 2025

By Paul Billingsley

THE purpose of this paper is a comparison, based on genesis, of the ore deposits associated with the igneous rocks of the central Montana Rockies. Considered separately, without attention to their origin, the orebodies appear to be distributed haphazard, with no fundamental laws controlling their position and character. It is believed, however, that if all the factors be weighed, this apparent confusion will to a large degree disappear. The, first essential to such a comparison is detailed knowledge of the individual mines, as to their geographic position (see Fig. 1), their mineralogical character, and in particular the derivation of their ores.1 The authors of this paper have pursued such an investigation for the past 6 years, and have accumulated a mass of evidence that enables a preliminary correlation to be attempted. It appears that the majority of ore deposits are genetically related to one or another of the igneous

Jan 4, 1917

By Nuno Cruz, Saúl Rodríguez

"When executing offshore bored piles there are several specific factors and problems to consider in order to guarantee excavation stability. One of the methods employed to carry out this type of work consists in setting up a floating work platform, typically a barge, and implementing a soil stabilization system that combines a partial steel guiding casing with third generation polymeric drilling fluids. The main aspects to take into consideration when performing offshore pile boring works are soil stabilization, project design, work methodology and operational aspects. An example of a work methodology problem arises before any pile boring work takes place as the steel guiding casing contains water, sometimes salt water. What to do with this water in order to replace it by an adequate polymer fluid will determine the stabilization capacity as soon as the shaft advances below the protection of the casing. Another example of operational problem may derive from barge movements while executing boring activities. This study is the result of extensive field data collection and concrete logging analysis from marine projects using polymers in different continents. The bored pile stability target was set ranging between 2% to 15% of concrete overbreak. Values above 15% or below 2% mean that there is a stability problem. Then the off-target pile’s data is collected, analyzed and classified under categories. Thus, a direct correlation is established between the problem category and the final results. Modifying steps in the pre-established construction methods or operational variables guarantees target results without the need to replace the approved construction methods. As a general conclusion, the worldwide experience in large diameter marine works, allows to provide truthful information and solutions for these problems. In knowing how to follow a logical sequence of work and applying adequate work methodology will be the key for success.GENERALBackgroundTo carry out the drilling process of offshore bored piles there are two main options to take into consideration: drilling the pile by using full guiding casing until final depth; or using a combined system of partial steel guiding casing and support drilling fluids.The knowledge and situations described in this paper come from the experience acquired in different projects where the second method was employed. This construction method consists in installing a steel guiding casing by vibration and thus covering the water table and further stabilizing the soil below it with polymeric fluids until reaching the pile’s final depth. The Fig. 1 schematic shows an example of this method where H corresponds to the length of the steel guiding casing whereas the remainder of the shaft’s length is stabilized by polymer fluid. The entire bored length is full of slurry up to top of casing.In most cases this kind of civil works results from the need to build a bridge or executing port structures in places where the creation of temporary artificial peninsulas with fill material is impracticable or not allowed. Hence the need to use floating work platforms, commonly referred to as barges."

Jan 1, 2017

By W. D. Monaghan

Flame cutting and welding is one of the major causes of fires and explosions in underground U.S. coal mines. On May 20, 2006, a flame cutting operation at the Darby Mine No. 1 led to an explosion that resulted in five fatalities. On January 22, 2003, another explosion caused by flame cutting at the McElroy Mine resulted in three fatalities and three serious injuries. On June 22, 1999, a flame cutting and welding operation at the Loveridge Mine caused a fire that resulted in sealing of the mine for an extended period. Finally, on March 19, 1992, an explosion at the Blacksville No. 1 Mine that was caused by welding resulted in four fatalities. The National Institute for Occupational Safety and Health (NIOSH) conducted a study on fires and explosions in underground U.S. coal mines that were caused by flame cutting and welding operations to determine the root causes of these types of fires and explosions. The methodology included interviewing mining personnel who perform flame cutting or welding operations in underground U.S. coal mines and visiting mines to observe these operations, and MSHA reports of investigations and accidents statistics were analyzed. The results were used to identify and compare differences between flame cutting and welding practices and techniques in small and large mines, Eastern and Western mines, low seam and high seam mines, room and pillar and longwall mines, and between experienced miners and new miners. As a result of this study, best practices and interventions were developed to reduce the number of fires and explosions caused by flame cutting and welding. This paper provides a summary of this work. Disclaimer: The finding and conclusion in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupation Safety and Health.

Jan 1, 2009

By da Silva C A, Tenorio J. A S, de Assis R M, de Oliveira J R

For Fe-Mn alloy production, two reactions are responsible for this process: the MnO reduction in the slag and the carbon dissolution in the bath. The smelting-reduction process has been studied as alternative route to be used to produce alloy so as steel. This technical paper presents some initial studies to be used to determine the main ways that one can have for the mechanisms for this reaction. The limited factors like mass transport or chemical reaction were analysed. The Mn content in the bath were varied and it was concluded that by increasing the former, dissolution of Mn into the bath was increased, so as a reduction of MnO in the slag. For carbon dissolution, it was used a experiment with a stationary bar, this one was added into the bath, after ten minutes probes were catched, by temperature 1600¦C, for the dissolution of MnO, one graphite crucible was employed, after 45 min the slag and alloy were analysed. After the experimental part, some curves were plotted against time, based on these graphics, and kinetic analysis was made.

Jan 1, 1999

By M. R. Pickus, I. W. Pickus

ORDINARILY age-hardening is thought of as being associated with a limited solubility of one metal in another. Much less has been written about the type of age-hardening that attends the formation of superstructures. Solid solutions generally have a disordered or random arrangement of atoms; that is to say, in a unit cell, such as that of the face-centered cubic lattice, there is no distinction between atomic sites. Atoms of a given metal may occupy cube corners or face centers. Under certain conditions, however, some alloys develop what is known as an ordered structure. In this case, cube corners would be occupied by only one type of atom and face centers by another type, Associated with this ordering process are many interesting changes in physical and electrical properties. Moreover, in many instances the alloys become susceptible to age-hardening. From the evidence now to be described, it appears that age-hardening in 14-carat gold alloys is due to the formation of both a super-structure and a precipitate. Alloys of the metals gold, silver and copper were known in antiquity. The available knowledge regarding their constitution has been ably summarized and extended by Sterner-Rainer,1 Janecke,2 Carter,3 Wise,4 and Coleman.5 Despite the long familiarity with these alloys and the numerous investigations of their properties that have been made, there is still much that remains unexplained. It has been known for a long time that the hardness of these alloys is closely related to the rate of cooling, Similar changes have been observed in the binary gold-copper system,6 one alloy of which corresponding to the formula Cu3Au, has been the subject of a careful and competent report by the English investigators, Sykes and Evans.7 They have established the fact that the shift of atoms from the ordered to the disordered condition takes place in some critical temperature range. At temperatures above the critical range the structure is random, and at temperatures below it the structure is ordered. No difference between these two structures is revealed by the microscope. Both have a face-centered cubic lattice and complete solubility, so that there is no evidence to suggest that the changes in properties are associated with a phase change, The more slowly the alloy is cooled, the higher is the degree to which the ordering process proceeds and the more marked is the increase in hardness. As experimental data were accumulated on 14-carat gold alloys, several contradictions arose. Certain observations tended to confirm the existence of a superstructure, while other observations seemed to be inconsistent with such a transformation. PRESENT INVESTIGATION As a focal point about which to develop this subject, it is expedient to consider first

Jan 1, 1943

By Gualberto Carpio

El presente texto señala la metodología desarrollada en Tintaya para la identificación de posibles proyectos, los cuales están enfocados con los objetivos del negocio y del líder del área ya que comparten metas comunes de mejoramiento. Esta mejora alcanzada con Six Sigma, solo es posible con el soporte del plan estratégico de la compañía y por ende, se hace énfasis en la correlación que existe con los proyectos a desarrollar en todas las áreas. En este sentido, el plan estratégico es alineado y controlado por indicadores clave de desempeño (KPIs) de primer, segundo y tercer nivel, los cuales indirectamente norman el desarrollo de los proyectos planteando metas de costos, incremento de producción, productividad, reducción de tiempos de ciclo, etc.

Sep 19, 2006

By Rob Thomas

Adequate load transfer is considered essential for optimum ground support and is increasingly important in weak roof and/or high stress environments. If adequate load transfer is achieved not only can this have a positive impact on the resulting roof behavior, but it may also allow the use of lower and hence more economic densities of roof support. A wide variety of post-groutable cable bolts are currently in use in the Australian coal mining industry, each of varying capacity, design, and grouting methodology. Though all of the cables are supplied with the appropriate steel specification, strength, and modulus data, the Australian coal mining industry does not have access to a comprehensive and comparative database on the corresponding load transfer performance, which is a critical problem. On the basis of the above, this paper describes the methodology and results of a laboratory pull testing program that aims to assess the impact of cable bolt design on load transfer, and specifically, the impact on the capacity and stiffness of the anchorage. As part of the testing program, 19 cables were tested including (1) plain-strand cables installed in holes drilled with 28 to 55 mm diameter drill bits and (2) bulbed and nutcaged cables installed in holes drilled with 42 to 64 mm diameter drill bits. Other parameters assessed included the significance of smooth and profiled wire, wire packing, and expanded geometry bulbs. The main results of the testing indicate that in comparison to plain-strand cables, if the cable is bulbed or nutcaged, the capacity of the anchor can increase by up to 400%, and the peak stiffness by between one and two orders of magnitude. The results also indicate that increasing hole diameter may have a positive impact on load transfer in the case of bulbed or nutcaged cables and a negative impact on plain-strand cables. No conclusive results were obtained with regard to the impact of grout strength on load transfer.

Jan 1, 2012

By D. S. F. Silva

A survey of 120 recent NI 43-101 technical reports was conducted to evaluate the current state of practice regarding resource classification techniques. The most common classification techniques are based on search neighbourhoods (50% of recent reports), drill-hole spacing (30% of recent reports), and/or kriging variance (6% of recent reports). Two new techniques are proposed. The first is based on kriging variance and involves removing one or more drill-holes with the highest weights while performing kriging and using the resultant kriging variance for classification. This technique has the advantages of variance-based techniques and reduces artifacts. The second technique is based on conditional simulation and uses a moving window approach for classification at the desired selective mining unit resolution based on larger production volume criteria. This technique has the advantage of accounting for heteroscedasticity, which is a common characteristic in mineral deposits, and also reduces artifacts since a production volume scale is considered for the actual classification. The drill-hole spacing, search neighborhood, kriging variance, and simulation-based techniques are described and compared for 2D and 3D examples with regular and irregular drilling patterns to highlight the advantages and disadvantages of each method.

Jan 1, 2014

By R. B. Crookston

Oil shales differ from coals in that they contain less carbonaceous material, convertible to volatile hydrocarbons, and more inorganic rock. In all pre-commercial oil shale development, involving extensive full scale mining operations, there have been no explosions. However, large scale mine tests with oil shale dusts by the Bureau of fines showed that propagating explosions could be induced under certain circumstances. Laboratory tests were conducted on a broad spectrum of oil shale dusts to define chemical properties and to seek correlations with subsequently determined fire and explosivity properties. These latter properties, indicative of safety hazards, increased as the Fischer assay oil yield of the dusts increased and as particle size decreased. Laboratory data were used to relate fire and explosivity properties of oil shales to those of coals and other carbonaceous materials and to assist in the identification and evaluation of potential hazardous situations which may be encountered in oil shale mining and processing.

Jan 1, 1978

By William M. Dowall

The recently completed in-pit crushing and conveying project at Phelps Dodge's Morenci Mine is rated among the world's leading materials handling projects. The operation involves the crushing and transport of more than 109 kt/ d (120,000 stpd) of copper ore, using regenerative conveyors capable of providing more than 5.5 MW (7000 hp) of equivalent electrical energy. The Morenci Mine is located 330 km (200 miles) east of Phoenix, AZ. Phelps Dodge Corp. owns an 85% interest in the mine. The remaining 15% is owned by Sumitomo Metal Mining Co., Ltd. and Sumitomo Corp. Copper has been continuously produced from the Morenci district since the late 1800s. Until 1989, run-of-mine ore was transported from active mining faces to the Morenci and Metcalf concentrators by truck and rail haulage. In that year, a system of in-pit, semi-portable crushing plants and overland conveyors was commissioned. This substantially reduced truck haulage and effectively eliminated rail haulage in the pit. The system used two semi-portable, in-pit crushing stations equipped with 60/89 gyratory crushers. The crushed ore from both plants reported to the first of two overland belt conveyors, arranged in series, for transport from the pit to a coarse ore stockpile. The system was "backed-up" by existing locomotive rail haulage.

Jan 1, 1993

By Karl Nienhaus

The BGMR has developed a method for an online-analysis during drilling processes in cooperation with Fraunhofer Institute for Laser Technology in Aachen and various industrial partners. This allows for efficient utilization of deposits, maximum recovery of desired minerals and frequent and costefficient updates of deposit models. The used method, namely laser-induced breakdown spectroscopy (LIBS), was implemented into a compact demonstrator in order to analyze drill dust and loosened material within mining environments and directly on drill rigs. The consequently developed OFURanalyzer (OFUR ? online-analysis of mineral deposits) provides possibilities for exploration and visualization of deposit models in real-time and thus creates an opportunity for innovative applications, such as contactless, continuous quality control of minerals throughout the extraction process. A major challenge in the execution of this project was the necessity to develop a laser system that could withstand rough mining environments dominated by dust, shocks, vibration and therefore would be suited to operate under such conditions.

Oct 1, 2009

By Iman G. Ghanad

El presente texto describe un nuevo método para el tratamiento de concentrados de cobre con alto contenido de arsénico utilizando el carbón activado como catalizador. Para ello, se realizaron pruebas de lixiviación con concentrados de enargita de tres minas de Chile, Perú y Estados Unidos, donde los resultados señalaron que la disolución de la enargita fue más rápido con la influencia del carbón en la solución lixiviante, incluso después de haber reciclado el carbón.

Sep 12, 2011

By F. D. Everett

Thermoelectric and metal alloying applications have changed the status of tellurium from oversupply to under supply . In a search for new sources of this element in Arizona , Colorado , New Mexico , Utah , and neighboring states , the Bureau of Mines analyzed more than 200 samples and obtained the results of tellurium determinations by private companies on more than 500 samples from a wide variety of mineral - bearing deposits . The About 40 minerals containing tellurium have been reported , mainly tellu- rides of gold , silver , bismuth , mercury , lead , copper , iron , and nickel . minerals usually occur in small quantities and identification in ores is extremely difficult . Samples containing more than 0.1 percent tellurium were taken from the Hilltop and Memphis properties in Dona Ana County , N. Mex . , and the Silver King property in White Pine County , Nev . , where development was chiefly for base metals . The Lone Pine mine in Catron County , N. Mex . , and the Bambolla mine near Moctezuma , Sonora , Mexico are potential sources of native tellurium occurring in small but high- grade pods . Much of the production of tellurium has come as a byproduct of electro- lytic refining of copper and lead- zinc ores in Arizona , Colorado , New Mexico , and Utah . Base -metal ore deposits will continue to be the most important pri- mary source of tellurium , although the concentration in ores is nearly always less than 10 parts per million . Any significant increase in output of tellu- rium probably will be related to production and improved efficiency in smelt- ing and refining base - metal ores .

Jan 1, 1964

By Guangqing Zhang

The paper presents results of a systematic study of synthesis of titanium oxycarbide and its chlorination. Titanium oxycarbide was produced by carbothermal reduction of titania in hydrogen, argon and helium. Formation of titanium oxycarbide started at 1200°C in all gases. The reduction was the fastest in hydrogen. Formation of titanium oxycarbide in hydrogen was close to completion in 120 min at 1300°C, 60 min at 1400°C and less than 30 min at 1500°C. Reduction in argon and helium progressed at a similar rate and reached 90-95% after 300 min at 1400-1500°C. The chlorination of titanium oxycarbide was ignited at 150-200°C. Chlorine partial pressure and gas flow rate strongly affected the chlorination rate. Chlorination of titanium oxycarbide produced with carbon to titania molar ratio 2.5 at 235-400°C was close to 100% in 30 min.

Jan 1, 2009