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By D. E. Salman, R. R. Maclachlan, R. J. Barclay

"There is a considerable resource of data for spherical charge cratering, both as single charges and in row-of-charge geometr(1). The data are. however, based on cratering performance to a single free planar surface.In practice. the more common circumstance involves an angular surf ace geometry. such as occurs at the toe of a bench or the wall of a stope. It is for the purpose of investigating this circumstance that the described test work was conducted.The test objectives were: (1) to observe the change in single-charge cratering performance between planesurface and angle geometry; (2) to identify the optimum performance of single charges cratering to a plane surface. cratering from a bench sub-grade position and cratering from a condition of zero sub-grade or stope wall geometry; and (3) to observe the performance of row-of-charges cratering to an angular surface at various row burials and spacing. The row charge burial and spacing dimensions were to be expressed in simple numerical multiples of single-charge depth-of-burial data."

Jan 1, 1981

Agenda ?Introduction ?Geology ?Mining ?Metallurgy ?Process, Layout ?Environmental Background ?Kinross Gold Corporation owns the Lobo-Marte gold property, located in Region III of northern Chile. ?The property is close to two other Kinross mines, Maricunga 50kmto the south and La Coipa 60km to the north, plus a regional office in Copiapo and district level operating synergies are expected. ?Lobo and Marte were discovered in the early 1980s and are intrusion-hosted, porphyry-type precious metal deposits, typical of the Maricunga District. ?The Marte open pit heap leach mine was in commercial production in late 1988, but was suspended in February 1992 as it did not meet forecasted production levels and recoveries. ?Kinross plans to recover ore from the Lobo and Marte deposits through an open-pit, heap leach47,000tonne per day operation.

May 1, 2010

By Todd Kennedy, Kurt Tischler

"This paper presents the field experience of Siemens with regard to Gearless Drives in the mining industry … We consider the elapsed production hours of Siemens Gearless Drives to be extensive enough to provide a reliable estimation of availability calculated on the basis of data representing repair time, downtime, and operating time. The users of Siemens Gearless Drives confirm an availability of more than 98% after exclusion of some major issues. The paper addresses all of these major issues of Siemens Gearless Drives, describes successfully applied corrective measures, explains the influences on the design of the drives, and lists the downtimes associated with each of these issues. INTRODUCTIONThe first Siemens Gearless Drive in mining began operation in 1980 and was installed on an iron ore grinding mill. As of September 2011, 40 Siemens Gearless Drives will have accumulated 136,000 machine days of operating time. According to pure rules of statistical analysis, this accumulated operating time may be too low to be used for a sample of field data to provide precise statistical values of availability, however we consider it large enough to provide indicative values of worthwhile consideration. This paper deduces the availability statistics of Siemens Gearless Drives in the mining industry from information received from end users and factors in all major issues that Siemens has experienced with our Gearless Mill drives. This paper does not consider Gearless Drives in other industries such as the cement industry. The cement plants, especially in the northern hemisphere, interrupt production for several months in the winter. This lengthy downtime is used to maintain the complete plant including the mills, their motors and their drives. The mining industry has more stringent and higher production requirements. In the mining industry, production must run 24 hours per day, 365 days a year."

Jan 1, 2012

By Li. L.

Backfilling has become a popular solution in underground mines around the world. It reduces environmental impact of mining industry and improves ground stability. In most cases, backfill has a high water content so that it can be delivered by pipes from a backfill plant on ground surface to underground stopes. Upon deposition in the stope, the backfill tends to consolidate under its own weight, leading to a generation of excess pore-water pressure. To avoid excessive pressure and protect the backfill barricade installed at the base of the stope, the backfilling of the stopes is usually divided into two stages: plug pour and backfill body pour. The interruption of backfilling operation is undesirable as it slowdowns the mining productivity, and sometimes causes pipe clogging, leading to unexpected increase in manpower cost and further reduction in mining productivity. The backfilling interruption time may be reduced, even eliminated if the drainage of backfilled stopes is sufficiently improved. This paper presents an application of wick drains, a material commonly used in civil engineering, to mine backfilled stopes to help accelerating the drainage. A protocol is proposed for installing the wick drains in a mine stope to be backfilled. Numerical simulations were made, showing that the drainage of the backfill can significantly be improved by the introduction of wick drains. The application of wick drains in mine backfill can thus be considered as a promising technique and merits deeper and more detailed investigation.

Aug 1, 2013

By P. M. Solozhenkin, O. I. Ibragimova, I. P. Solozhenkin

Molecular models of complexes of poorly studied bismuth, gold, and arsenic mineral clusters and reagents were created for use in collector activity forecasting using Chem Bio 3D and ChemOffice2005, with optimization by MM2. The density functional theory approach was used to determine HOMO, LUMO, SOMO, and total energies, atomic charges, and s, p, d- populations for various compounds. The structure-based virtual screening (SBVS) and docking technique was proposed to reduce the vast number of compounds to a more manageable number for selection of potential flotation candidates. The prognosis of collector activity evaluation (PCAE) strategy was proposed as a consistent approach to estimate the interaction between a collector and a mineral cluster as the difference between the total energy and sum of cluster energy and collector energy to search the analogue of butyl xanthate. The negative relationship between PCAE and flotability was shown. The combinations of dialkylamino sulfhydryl collectors can be considered as prospective reagents for gold-bearing sulfide ore flotation. These results were confirmed by experimental data in ore flotation. The increase in recovery of gold and bismuth with the aid of a combination of reagents has been established and additional cyanidation of tailings has been avoided.

Jan 1, 2016

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The use of large AG/SAG mills in the mineral industry has been on the rise recently due to a significant reduction in the capital and operating costs for achieving significant increases in plant throughputs. The major reason for downtimes in these mills is the time taken for the replacement of broken or worn liners. This loss of “availability” of these units has a significant impact on the productivity of these plant operations. The ability to predict liner life time and its evolving shape could help to optimize these comminution operations. In the past decades, various models have been proposed to estimate liner wear rate, but because of their empirical nature they could only be used within certain limited operating conditions. In this research, a phenomenological model which could predict the liner wear rate was proposed and tested. This model considers parameters such as; operating conditions, liner hardness, pressure on the lifter, and, relative velocity of particles and mill shell. Data from industrially measured liner profiles were taken during the liner life time at the Sarcheshmeh and the Gol-E-Ghohar SAG mills to provide a solid base to calibrate and validate the model. The comparison of the model predictions with the actual measurements of the liner wear rate showed that the results were in a good agreement at both, the Sarcheshmeh (R2=0.94), and the Gol-E-Ghohar (R2=0.97) concentrators.INTRODUCTIONAG/SAG mills are one of the most important technologies in the mineral processing industry in the recent decades. The “Availability” of these units in a plant operation is one of the most important economic parameter for evaluating their performance. The major reason for the downtime of these mills affecting their “availability”, is the time required to change worn or broken liners (Yahyaei, Banisi, & Hadizadeh, 2009; Maleki-Moghaddam, Yahyaei, & Banisi, 2012). The knowledge about the magnitude and profile of liner wear not only enables more accurate liner life estimation to prevent unwanted interruptions of the SAG milling in mineral processing plants and more strategically plan the scheduled mill outages for liner changes. It also could provide key information needed to select an appropriate liner design (Yahyaei et al., 2009; Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010a)."

Jan 1, 2016

By Frank Mucciardi, Louca Gourtsoyannis

"Low and inconsistent recoveries of aluminum in the production of aluminum-killed steels triggered an extensive research program on the aluminum dissolution kinetics at McGill University. This research program led to the understanding of the melting kinetics and the hydrodynamics of making additions to liquid steel. It showed the necessity of gradually releasing liquid aluminum at the bottom of the ladle to increase aluminum recoveries.This knowledge was verified in practice at Sidbec-Dosco, where a prototype aluminum wire injector was developed and installed for the first time in Canada. The industrial application showed the validity of the theoretical and experimental results and provided further data for the mathematical modelling of the process.The development of the theoretical understanding, the industrial results, and the interaction between university and industry are presented.IntroductionAluminum is an extremely effective deoxidizer of molten steel; nevertheless, an efficient method of adding it to steel has eluded steelmakers for many years. It is well known that the recovery of aluminum used in the production of aluminum killed steel is both low and eratic, especially when the aluminum is added in the form of bars or lumps from chutes into filling ladles, a practice still common in many of today's steelmaking operations.As the density of aluminum is only about 40010 that of molten steel, it is conceivable that loose bars of aluminum simply ""thrown"" into a filling ladle will resurface before any appreciable dissolution of the aluminum has occurred, particularly if the depth of penetration of the additions is small. Before one can conclude that this is indeed the case, it is necessary to know the melting kinetics of an aluminum addition. Back in 1972, this information was not available; hence an extensive research program which focused on melting kinetics was initiated at McGill University."

Jan 1, 1982

By D. C. Brady

"Within six months from award of a project management contract, Les Mines Dumagami Limitée, Cadillac, Quebec, was operating its new hoisting facility. This was accomplished with less than a six-week shutdown of mine production while still maintaining shaft access for underground maintenance.The work involved installing a refurbished /3.5 ft diameter double drum hoist, replacing a timber headframe with a newsteel headframe, increasing the ore bin capacity from 500tons to 1000 tons, constructing a new substation, and upgrading related facilities.This paper describes the work and methods used by various contractors, Les Mines Dumagami Limitée and J.S. Redpath Mining Consultants Limited to bring this project to a successful completion. It discusses the history of the project from proposal stage through to the design, procurement, scheduling, and construction management. The paper also comments on problems that were encountered and the methods used to overcome them.IntroductionThe Donald J. Laronde Mine of Les Mines Dumagami Limitée (Dumagarni), a gold and copper producer, is located in northwestern Quebec, approximately half way between Val d'Or and Rouyn. The mine started production in the spring of 1988 and the first gold bar was poured in June 1988.Following a request by Dumagami, on February 22, 1989, J.S. Redpath Mining Consultants Limited(Redpath) delivered a proposal to increase hoisting capabilities from 1500 tpd to a minimum of 2500tpd. Although various concepts were considered, Redpath proposed a new hoist house along the same shaft axis as the existing hoist, and located on the site of the existing substation. They would then provide a new substation, replace the headframe with a largersteel structure , gain extra storage capacities by increasing the bin heights, and raising the roof of the bin house accordingly.Although underground mining would have to be stopped for a month, the mill production would be maintained by feed from Dumagami's open pit.Figure 1 shows the original plant layout and Figure 2 represents the general arrangement after the project was completed . Table 1 compares the original hoisting facilities to the new facilities.On March 2, Dumagami awarded Redpath a contract that included preliminary engineering, detailed engineering, procurement and contract administration, and later added construction management. The preliminary engineering refined the initialconcept, selected major equipment, and prepared schedules and capital cost estimates for the total project."

Jan 1, 1991

By G. F. Trainor

At the Canadian Natural Resources Limited (CNRL) Horizon Mine they use Wenco International Mining Systems Ltd (Wenco) Fleet Management System to monitor and control their production fleet with the goal of increasing operator productivity and safety, and raising dispatcher awareness and control. Amongst the broad productivity goals CNRL wanted to achieve with help from the system was a very specific need to blend ore at the truck level. CNRL uses 25m x 25m block geological model information to represent their complex ore body. Wenco's High Precision GPS application, BenchManager provides precise graphical actual-vs-design operator feedback and system integration. Together the two companies advanced the BenchManager product to meet CNRL's needs by using live camera feeds to compare activity with data collection that ultimately lead to changes in the algorithm to include enhanced GPS indicators and the support of a GLONASS assisted solution generating distance and bearing information.

May 1, 2011

By G. J. Arseneau

ABSTRACT Mineral resource statements are reported as tonnage (volume × density) and grades. Effort is expended to accurately estimate the volume and grade, but accurately determining bulk density is often overlooked. Oversimplification of density modelling can result in potentially serious errors in tonnage estimates and over- or underestimation of metal content. A reliable bulk density model requires an adequate database and a good understanding of density variability, along with grade and geology. In this paper, the author summarizes density measuring techniques, draws on examples of simple and complex grade-variable density domains, and discusses improved approaches for minimizing density estimation errors.

Jan 1, 2014

By François Charette

High stress conditions in weak rock masses lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock failure. Typical support systems combine various reinforcement and support mechanisms to provide the required convergence control and retainment, but results are often mitigated by failure of surface liners, shotcrete and tendons. The paper reviews differing requirements of support and reinforcement for different failure types. In addition, the mechanical performance of a new reinforcing tendon is presented and analysed in view of the field requirements. Field tests results are presented.

May 1, 2011

By M. Saghaeian, R. Hejazi, Sheikhzadeh. V., A. Abazarpoor

"The morphology of iron ore concentrate particles is known to influence several properties of iron ore pellets, including drop number, compression strength, and reduction properties. This study aimed to determine why grinding methods and particle morphology influence green pellet properties. Particle morphology can be directly related to the grinding method: ball mill (BM) or high pressure grinding roll (HPGR). In this research, two iron ore concentrates, namely Gol-e-gohar and Ardakan, were ground by a BM and HPGR to produce a suitable Blaine value for pelletizing (nearly 1,900 cm2/g). Morphological features of particles were subsequently investigated by sieving and cyclone sizing for particle size distribution, the Brunauer-Emmett-Teller (BET) and Blaine methods for specific surface area (SSA) and scanning electron microscopy (SEM) for the evaluation of shape descriptors. It was concluded that HPGR resulted in generating a greater proportion of fine particles compared to ball milling. The BET results showed that the SSA of HPGR pellet feed was higher than that from the BM due to a greater proportion of cracks, indents and bulges and the creation of new fracture surfaces. SEM images processed by ImageJ software indicated that particles ground by the BM tended to be more rounded and less elongated than HPGR particles because of the breakage model of each method. To show the effect of morphology on the green pellet quality, green pelletizing was performed in a pilot pelletizing disc. The HPGR pellet feed had a higher drop number in comparison to the BM pellet feed, due to the angular and rough shape of the particles.INTRODUCTIONThe demand for fine or ultra-fine particles as feed material for ceramics, composite materials, and mineral processing is on the rise (Kotake, Kuboki, Kiya, & Kanda, 2011). The final concentrate of iron ore processing plants (filter cake) has a size range roughly between 0 and 300 µm, depending on the liberation of Fe containing particles (Meyer, 1980). In general, to produce a suitable pellet feed of appropriate quality, Blaine numbers of 1800–2000 cm2/g should be achieved (Van der meer, 2015)."

Jan 1, 2016

By X. X. Wu, Q. Zhang, R. H. Fan, Y. J. Feng, J. D. Liu, P. Z. Zhao

In the present study, AA6016 automotive sheets with different grain size were fabricated through changing fabricating parameters, and the effects of grain size on the bendability were studied by bending test and optical microscopy. The results showed that the sheet with coarse grains exhibited poor bendability, and some micro-cracks were revealed at the surface of the bending samples. While the sheet with fine grains exhibited good bendability, and the bending samples showed smooth surface. Shear bands on the cross section of bending samples were observed. It was found that samples with coarse grains had more shear bands. These shear bands distributed in bundles, which facilitated the formation of continuous neckings and micro-cracks. However samples with fine grains had less shear bands, which distributed uniformly. The decrease of grain size could not only hinder the formation of shear bands, but also improve the homogeneity of its distribution during bending. On the other hand, refining grains could increase the amount of grain boundaries, which impede the propagation of shear bands. Hence the decrease of grain size could hinder the formation of continuous neckings and micro-cracks during bending, resulting in the significant improvement of the bendability.

Jan 1, 2015

By Fatemeh Saeidi, Luis Marcelo Tavares, Malcolm Powell, Mohsen Yahyaei

"Understanding a single breakage mechanism is fundamental to the development of breakage testing techniques appropriate for mechanistic modelling of any breakage equipment. In the light of this insight, it is also possible to compare any two breakage events in a mechanistic manner. This paper presents a new method to compare breakage mechanisms of two-point impact with compression, different in their applied strain rates. This approach regards a single breakage event as a process affected by three sub-processes; first fracture, capture and spatial distribution of fragments. Spatial distribution is influenced by the kinetic energy of fragments and their brittleness. Using this methodology allows us to examine how each sub-process is influenced by applied strain rate and its impacts on progeny size distribution. For this purpose, two rock types of widely different strength, magnetite and silicate, were tested at various energy levels using the impact and compression mechanisms. To isolate the effect of spatial distribution of fragments, particles were forced to remain in the breakage zone. In this condition, similar progenies were generated from compression and impact mechanisms at similar energy levels. However, allowing natural distribution of fragments, coarser progeny was produced from compression of silicate. Additionally, using this approach provides a physical meaning and explanation for rock strength parameters such as A×b in the t10-Ecs relationship. INTRODUCTIONComminution models are rapidly progressing toward a destination that enables us to explain the complete physics of a breakage process as well as the properties of the ores. Eventually, they will be able to take into consideration the micro-events that take place during the comminution process (Bourgeois and Banini, 2002). Thus, considerable efforts have been made in the last few years in the area of ore breakage characterisation to comprehend and unlock a single breakage process that has been treated as a black box event in the majority of conventional methods. In this paper, an attempt is made to explain the effect of applied strain rate on the breakage properties of rock by using the knowledge that has been gained by understanding a breakage event. This is particularly important due to its application for various comminution devices that operate within a relatively broad range of speed."

Jan 1, 2016

By D. Thibault, A. Akhiate, M. Brochu, E. Braud

Cast martensitic stainless steels, 13%Cr-4%Ni, having carbon contents between 0.018 wt% and 0.067 wt% were normalized, air quenched, and tempered at two different temperatures (550°C and 610°C). Their microstructures were characterized by optical microscopy and X-ray diffraction (XRD). Macro and microhardness, tensile strengths, and impact resistance were quantified for each material and condition. Results show that the prior-austenite grain size is constant through the materials but the percentage of reformed austenite, contained in the martensitic matrix, depends strongly on the material chemistry and on the tempering temperature and on its duration. It is observed that, independently of tempering conditions, an increase in carbon content increases the material hardness and tensile strengths, whereas the elongation remains constant. In contrast, the results of Charpy type impact toughness tests show a different trend. The material containing the average carbon content (0.034 wt%) is significantly tougher than the two other alloys. Surprisingly, the toughness of the steel containing 0.034 wt% carbon was found independent of the reformed austenite content. It is thus concluded that carbon and reformed austenite contents are not the only parameters affecting the toughness of these steels.

Jan 1, 2014

By Mark B. Thorpe

Golden Star Resources started gold mining operations in Africa in 1999 after 15 years of exploration in South America. At the time, the approach to local assistance was through "alternative livelihood" programs and the donation of infrastructure to local communities. This was initially successful with local community support. However, with time and on reviewing the implemented projects, it became evident that the success was limited and many if the projects were either poorly used or in disrepair. Through a review of the options, we decided to develop a community assistance model driven by the communities themselves, while keeping control of the finances and the actual construction of the projects. Through the formation of the Golden Star Development Foundation, we began to support community driven projects for local economic development. The evolution of economic development projects continued over the next several years with the addition of project requirements for partnerships with government, and finally an evolution to a partnered turn-key piece of infrastructure that we hand over to an agency for operation and ongoing maintenance. We are currently working with outside partners to further our economic development activities in Ghana to the benefit of our stakeholders.

May 1, 2011

By Joseph Carlston

With environmental regulations continuing to restrict the discharge of phosphorus from wastewater treatment facilities, traditional methods of phosphorus removal are proving inadequate. To achieve the phosphorus control necessary, a new coagulant used for phosphorus removal, cerium chloride, has been studied in several municipal and industrial wastewater treatment facilities that must meet a phosphorus discharge limit of 0.5 mg/L or lower. These studies demonstrated the high phosphorus removal capabilities of cerium chloride, with the results illustrating the ability for cerium chloride to reduce phosphorus to low concentrations in the effluent using a lower volume of product as compared to traditional coagulants, such as ferric chloride. This reduction is due to the unique ability of cerium chloride to remove phosphorus as cerium phosphate, whereas iron- and aluminum-based coagulants rely on adsorption and co-precipitation.

Jan 1, 2014

By R. S. Boorman, L. J. Surges

"Ore reserves at Brunswick Mining and Smelting totalled 101(106) tonnes grading 97 grams tonne-1 silver at the end of 1981. Silver is recovered as a byproduct in the copper, lead and bulk concentrates and is lost to the zinc concentrate and plant tailings. Recovery of silver for the year 1981 was 58,5%. The loss of potential revenue is in excess of Cdn $50(106) year-1 at current silver prices and milling rates.Silver is known to occur in solid solution in galena and as tetrshedrite. Evidence indicating the identity and significance of a third silverbearing mineral assemblage is reviewed and the distribution of silver losses is detailed. Characteristics of each the carrier which may be responsible for observed distribution, including size, surface quality, liberation and composition are considered, and the third carrier is shown to have possible implications for improved silver recovery by other Canadian producers as well as by Brunswick Mining.Silver tetrahedrite tailings distributed tailings and losses occur as coarse, free and as very fine unliberated galena in losses of the third carrier are between the zinc concentrate and are concentrated in the finest size fractions. Process alternatives for enhanced silver recovery by physical and chemical means are reviewed."

Jan 1, 1983

By Peter J. Franklin

"Short-term mine planning of open pits is an activity that has historically been carried out by hand. Typically, the use of computers has played little part in this type of mine planning. This paper describes the objectives and the procedures involved in short-term mine planning, comments on the type of computer systems available, and describes in detail a computer-aided short-term planning and scheduling system known as STEPS.IntroductionThe mine planning department of any o pen-pit mining operation performs a wide variety of different tasks. However, their primary concern is the preparation of detailed long-and short-term mine plans. These mine plan s will define the long-term operating strategies and definitive everyday working plan s for the ongoing development of the open pit.In this day and age, when operating costs have spiralled upwards due to inflation , and product revenues have decreased due to depressed economies and poor markets, it is vitally important for all aspects of the mining operation, including mine planning, to be efficient and cost effective.There are numerous options available for planning engineers when generating a mine plan. A cost effective mine plan must investigate all these options and select the optimum. When using manual planning techniques, it is often impossible to evaluate all the available options. To do this, and to produce an optimum mine plan, a computer is required.This paper discusses mine planning, with emphasis toward the short-term plan and comments on how the processes may be computerized. It also describes in detail, a computer software system called STEPS, which has been designed as an interactive graphics, computer-aided short -term mine planning and scheduling tool."

Jan 1, 1985

By Janice Zinck

?Past? Images of Mining ?Historic practices have been poor ?Mining still widely perceived as environmental ?spoiler? ?Public only hears the bad news stories. Lessons Learned from the Past ?Sustainability matters ?Recognition of social and environmental responsibilities ?Recognition of importance of public concerns and perceptions ?Community engagement

May 1, 2009