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By Waldemar W. Koczkodaj, William O. MacKasey

Abstract - A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simplified case of volcanic-associated massive sulfide type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of nonmeasurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to refine at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By Waldemar W. Koczkodaj, William O. MacKasey

A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simpli?ed case of volcanic-associated massive sul?de type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of non-measurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to re?ne at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By B. W. Clyburn

"Coals from the Corporation's Lingan and No. 26 mines are classified as high-volatile A bituminous, with a very low inherent ash and containing all essential properties to provide metallurgical coal, with the exception of a high sulphur content. Only through proper cleaning at low specific gravity can the pyritic sulphur fraction of the coal be liberated to an extent where final sulphur meets coking standards. This first section of the paper deals with the operation of a Dutch State Mines heavy-media cyclone circuit to achieve an actual separation in the region of 1.30 specific gravity. A discussion of the parameter of control which must be applied along with an appraisal of the results obtained is included in the paper.Introduction Very high fluidity and unusually low ash are the outstanding characteristics of coal from Devco's mines in the Harbour seam of the Sydney coal field. However, sulphur content, mainly pyritic, ranges from 1 to 2.50Jo. To obtain the low and consistent sulphur level required in metallurgical coking coals, preparation at low specific gravity is required. Metallurgical coke is used as the fuel in an iron blast furnace. Its sulphur content largely determines the quantity of slag required to remove it and therefore influences furnace productivity and unit costs. Typical data on the various coal properties of importance in the production of coke are included in Table 1."

Jan 1, 1985

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 Nirmal Weerasekara

Mill liners serve the dual purpose of protecting the shell from wear and transferring the rotary motion of the mill to an effective grinding action. As the liners wear, the efficiency of energy transfer changes, so there is balance between liner profile for wear and for milling efficiency. A tool that can simultaneously predict the evolution of the liner profile and the associated change in milling efficiency should prove most useful in optimal liner design. This paper presents such an approach, based on measured 3D liner profile data informing 3D DEM simulations of charge motion and liner wear modelling.

Jan 1, 2012

By J. M. Belland

This paper deals with the geology of the Smallwood mine in relation to its influence on mining and milling operations. Structure within the orebody, and variations in ore grade and material types, will be described and associated with the various drilling, blasting and milling operations. The orientation of planes of weakness, either bedding or jointing planes, and contacts between extremes in material types influence the size of the broken material. Generally speaking, variations in grinding rates and recovery can be associated with stratigraphic sequence and metamorphism.

Jan 1, 1966

By J. M. Janssens, Van Quach Tinh, M. Ruel, R. Leblanc

"Microscopic studies of peat moss indicate a highly porous material. In view of using this natural product as an adsorbing agent for the treatment of polluted water, studies of its adsorbing power for beef extract and alkyl benzene sulphonate solution were determined. The effects of time of contact, particle size, concentration of adsorbent and concentration of pollutant were studied. In the case of beef extract, there is a COD reduction of around 27 per cent; in the case of the alkyl benzene sulphonate, the percentage reduction varied from 72 to 95 per cent. A water treatment plant based on the adsorbing power of peat moss with simultaneous recuperation of the pollutant is proposed."

Jan 1, 1971

By G Anders

The mucking out of sub-level headings by slusher and by Autoloader is described, and the performance and costs of both methods are compared. The introduction of the Autoloader is taken as an example to illustrate the meth-od used at the mine for evaluating the suitability of new equipment. The consecutive steps in the process are covered in detail -from the preliminary cost analysis and the preliminary estimate of savings and advantages, and the review of these data after a field investigation, through the elimination of dubious factors, and detailed time and performance studies at the property, to the final assessment of the new equipment and an evaluation of the initial forecast. The Autoloader in Operation. 1198 Introduction AT Mattagami Lake Mines Ltd., the mine workings are laid out basically on a pattern of 60-ft.-wide stapes alternating with 60-ft.-wide pillars, with stope lengths varying from 80 to 200 ft. and stope tonnages generally between 80,000 and 200,000 tons. Stapes are drilled off from sub-levels at 60-ft. intervals, with the

Jan 1, 1965

By Lionel A. York

THE first application of the cementation process took place in the year 1864, according to H. Standish Ball, when a break in the brickwork lining at a depth of 270', in one of the Rhine Preussen pits near Homburg, was sealed by running in milk of cement from the surface by means of a small hand pump. At about the same time Monsieur Portier adopted the method in France for repairing breaks in shaft lining. Figure 1 is descriptive of the Portier system and is of interest when compared with modern practice. During the next thirty years numerous attempts were made to improve the process; the general method used in sinking being to put clown bore holes outside the perimeter of the shaft for the purposes of injection. The cementation process was first recognized as an important as-set to mining in 1896 when Monsieur A. Francois developed his method of boring and injecting inside the shaft below the permanent water level. The Francois cementation process rapidly attained fame on the Continent and many shafts were sunk by its use in France, Belgium and

Jan 1, 1961

By J. W. Craig

THERE are, broadly speaking, three classes of refractories: acid, basic, and neutral. Fireclay, diaspore, silica, and the sillimanite group of minerals are included in the acid class, which for the most part are not very resistant to basic slags. The neutra! class includes chrome, graphite, and silicon carbide, while most important in the basic class are magnesite and dolomite. Although chrome is a neutral refractory, it has no sharp distinction from magnesitic refractoriness. The two are mineralogically (1) and chemically related, and there is available on the market a complete range of brick from straight chrome to straight magnesite. In many indus trial applications, one. type may be replaced by another. The present paper is confined entirely to such refractories. The following types of basic and neutra! brick, each sold under sorne special trade name, are available for use in Canada: (1) Burned chrome from crude ores (2) Burned chrome from treated ores (3) Chemically bonded (unburned) chrome-magnesite ( 4) Burned chrome-magnesite (5) Chemically bonded ( unburned) magnesite-chrome (6) Chemically bonded (unburned) high-iron magnesite (7) Burned high-iron magnesite (Regular) (8) Burned low-iron magnesite (9) Burned olivine-magnesite (10) Burned magnesitic dolomite-chrome (Magnecon) (11) Chemically bonded magnesitic dolomite-chrome (Magmecom) (12) Dolomitic brick

Jan 1, 1936

By A. N. Shen

Fe3A1 intermetallics are potential inexpensive candidate for hot applications. In this project, torsion tests on hot-rolled and annealed Fe3A1 (Fe-15.5A1-5.8Cr-1.0Nb¬0.05C) were carried out over the ranges 750-950°C and 0.01~1s-1 . The experimental results showed that when peak stress op>90MPa (LogZ>16s-1 , Z: temperature-compensated strain rate), specimens cracked at randomly low strains. Optical microscopy exhibited original elongated grains and many grain boundary cracks associated with segregation. With op<40MPa (LogZ<16s-&apos;), specimens deformed with low random op but considerably high fracture strains; slowly propagating cracks may explain the reduced flow stress. Optical microscopy showed both elongated grains and equiaxed subgrains with some indications of geometric dynamic recrystallization (gDRX) and of static recrystallization (SRX). Compression tests gave higher stress with little effect of the preexisting cracks. The activation energy Quw of current material in satisfactory torsion and compression tests is about 10% higher than previously published. Fe3A1 has body-centered cubic structure in the experimental range, so it was compared with ferritic stainless steel 434C (Fe- 16.55Cr-0.96Mo-0.21Ni). Constitutive constants and restoration mechanism are compared between these materials. While Fe3A1 is hardly a light metal, it is considerably lighter than most steels. Furthermore, like the other body centered cubic metals (BCC) (a-Fe, ß-Ti, ß-Zr and ß-brass), it exhibits a high degree of dynamic recovery (DRV) like Al alloys, producing easier hot workability than that of austentic stainless steels.

Jan 1, 2007

By Imane Benhamed, Jaouher Diouani, Laurent Cassayre, Florent Bourgeois, Carine Julcour-Lebigue, Université de Carthage

The attrition-leaching process aims at improving leaching performance when formation of passivation layers at the surface of leached particles is a severe limiting factor, as discussed recently by Julcour and coworkers (Julcour et al., 2015). This paper proposes a geochemistry-based modelling scheme for deriving the window of possible operating conditions for the attrition-leaching process to match the properties of the processed ore. The rationale is that the attrition-leaching process maintains the surface of reacting particles in an unpassivated state by continuous mechanical removal of surface leach layers, so that the process reactions can be modelled from thermodynamic equilibria throughout the duration of the process. The strength of the proposed modelling approach is that it bridges the gap between the properties of the ore and the process operating conditions. The present paper exemplifies the proposed process modelling route for derivation of the attrition-leaching process operating conditions in the context of the leaching of silicate ores, matching model predictions against controlled laboratory experiments. It is shown how thermodynamic modelling, when used in conjunction with a solid knowledge of the phases present in the system, can assist with deciding upon suitable process operating conditions. As an example, this firstprinciple modelling approach predicted that steel grinding medium would be converted into siderite (FeCO3) under a wide range of operating conditions, which led to questioning this initial choice of grinding medium for the attrition-leaching process under mineral carbonation conditions. It is emphasised that the same approach could be applied to ores of greater economic significance.

Jan 1, 2016

By James K. B. Booth

The natural crustal abundances of the principle metals of commerce are examined in relation to production and prices for each metal. Two factors, the abundance x price ratio (BP factor) and abundance/production (B/T factor) are listed for each metal. Ideally, for these desirable commercial metals, each factor should be a constant and the same for all metals; comparing the divergences for the full list of metals allows conclusions to be drawn on the relative degree of natural availability of each metal and the ease or difficulty of winning the metal from the earth's crust. Plotting the two factors for each metal over the past decade of steady industrial usage illustrates the anomalous position of copper and, to a lesser degree, molybdenum and it is concluded that over the long term the price of copper will continue to rise steeply. Possible future prices for copper are examined and a suggested preferred order of ranking of the metals as exploration targets would be copper, nickel, tin, zinc, silver, molybdenum and lead, for the near term, with molybdenum possibly increasing its ranking in the list within the next decade.

Jan 1, 1971

By S. Constantinides

"A major use for many of the rare earths is in permanent magnets. While alternate technologies are in research or already exist, rare earth magnets are unlikely to be supplanted as a major input to clean technologies and high efficiency consumer and industrial devices. We’ll examine where and how the magnet rare earths are utilized and the size of the market. Market growth forecasts based on global markets will be presented. A brief explanation of materials research in the US completes the material.INTRODUCTIONRare earth magnets, first commercialized c.1969, have become essential for a wide range of consumer, industrial and military devices. They are used in the speakers and vibrator motors of cell phones. Rare earth magnets spin the hard discs within the drives and rare earth magnet voice coil motors position the read/write head over the spinning platter. Rare earth magnets are the heart of motors and generators used on airplanes – they are smaller and lighter weight than alternative materials/devices. Now rare earth permanent magnets are being introduced into electric vehicles and wind power generation.Rare earth minerals are difficult to extract from the ores and to separate from one another. The increase in use of rare earth magnets has placed a severe strain on established sources of supply. The establishment of new mines and processing facilities is costly and requires upwards of 15 years to become productive. The combination of rapid rise in use of rare earth minerals coupled with supply shortages has caused rapid price increases and threat of non-delivery of product. The result of this disruptive situation has been a profound response at several levels: corporate, industry-wide and governmental. Let’s learn more about why rare earth magnets are so important to modern society."

Jan 1, 2012

By Dani J. Alldrick, Alastair J. Sinclair, Colin I. Godwin

"Abstract - The Stewart mining camp has a long history of precious and base metal mining. The camp is abundantly mineralized, with more than 200 widespread, varied, vein prospects, deposits and orebodies. These show wide variations in the mineralogy of ore, gangue and alteration assemblages, and wide variations in textures and structural settings. This report establishes the timing of the different metallogenic epochs and suggests a specific exploration application for systematic lead isotope analyses.Galena lead isotope ratios from a range of mineral occurrences indicate that all these varieddeposits formed during two main mineralizing events. Lead isotope data from the Stewart mining camp do not provide absolute ages for the formation of mineral deposits, but the relative distributions of data are consistent with dates determined in other studies. One ore-forming episode occurred in the Barly Jurassic and the other in the Middle Eocene. Both metallogenic epochs were brief, regional-scale phenomena. Sorne deposits from the younger mineralizing episode were em­ placed adjacent to or superimposed on the older deposits.Field and laboratory studies show that the two metallogenic epochs are characterized by different base and precious metal suites: Barly Jurassic gold-silver-zinc-lead-copper; and Middle Eocene silver-lead-zinc. Therefore, showings of different ages have different base and precious metal potentials and deserve different exploration emphasis. Lead isotope studies provide a reliable, cost-effective method for evaluating the age and commodity potential of small or recently discovered mineral showings and for setting exploration priorities on properties with several varied mineral occurrences . The determination of the age and metal potential of a prospect at an early stage of exploration may govern the urgency, intensity or even the necessity for further exploration work."

Jan 1, 1993

By J. George Gregr

"This paper gives a brief review of grinding mills installation procedures with special emphasis on future maintenance. The importance of cooperation between the customer, construction contractor and manufacturer&apos;s representative is discussed, as well as the imparlance of complying with standards, specifications and the keeping comprehensive installation records.Fundamentals of mill maintenance are explained with the aim being to maximize the equipment availability and to minimize unscheduled downtime. The paper also includes development of wear items design, based on operating conditions, drive components and bearings, and how to keep large gears healthy thus eliminating surprise failures.Experience with installation of a large gear on a 34-foot diameter mill in Lornex and successful application of a computer program for the gear alignment on the mill are given.IntroductionSuccessful operation of a concentrator begins with the engineering of the project and continues through selecting the right equipment, its installation , start-up period, and ends with final tuning of the process. machinery and the human factor into an efficient and viable industrial complex.The following is a brief review of grinding mill installation procedures with special emphasis on future maintenance. Fundamentals of mill maintenance are discussed with the aim being to maximize the equipment availability and to minimize unscheduled downtime, with some specific points on key grinding mill components such as bearings and drives.Finally, the experience is recounted with the installation of a large ring gear on a 34-foot diameter mill at Lornex, and the successful application of a computer program for the gear alignment on the mill."

Jan 1, 1985

By T. I. Urbancic, C-I. Trifu

"ABSTRACTSeveral case studies are presented on the use of seismic techniques to map active structures, evaluate changes in stress levels, and identify the conditions leading to large magnitude seismic events and the generation of rock-bursts in Canadian mines. The results suggest that microseismicity can be used to identify the orientation of active fractures; define regions of relatively high and low stress, and those most likely to host a rockburst; determine the role of local stress on observed shear failures; and identify the path of stress transfer associated with the remote triggering of rockbursts. Additionally, the conditions leading to rock-bursts can be characterized by a significant increase in the clustering of microseismic events along the fault plane orientation of an impending event, and an increase in the effective stress levels. It is concluded that the analysis of microseismicity provides the means for remotely monitoring rock mass behaviour as a result of mining."

Jan 1, 1997

By Karl Dufresne

Blasting in geothermally high temperature ground and/or extremely reactive ground is an increasing common challenge for surface and underground mines. Many current PETN based non-electric and electronic detonators have manufacturer published in-hole temperature limits ranging from 55°C to 65°C (131°F to 150°F). When confronting blasthole temperatures above the manufacturer published limits, operations may request site-specific guidance and qualification for use. The advised safe loading window for in-hole PETN based detonators is often too short to be practicable for production blasting. To overcome limitations of PETN based initiation systems, surface mines with high temperature ground and/or reactive ground are known to load blastholes with a qualified high temperature bulk emulsion that are top primed with a cartridge of temperature qualified detonator sensitive emulsion plus an RDX detonating cord downline. As there is no in-hole delay detonator in this system, blasthole timing is accomplished with surface delays. Although this system is safe, top priming and surface delaying does influence floor quality and top size fragmentation, and safe loading windows times reduce blast block size and increase blasting frequency. A mining company with a site characterized by geothermally high temperature ground plus highly reactive ground employed a blasting system like the one described above. The site desires to improve blasting performance by moving to an in-hole delay initiation system that can withstand the site ground conditions. At the request of the mining house, DynaEnergetics developed an electronic initiation system for application in geothermally high temperature ground and/or extremely reactive ground conditions. The DynaEnergetics IGNEO high temperature electronic initiation system is rated for in-hole use in ground up to 150C (302°F) for 48 hours. The detonator consists of a high strength detonator with an HMX base charge and thermally resistant downline. To make up a primer, the detonator is inserted into a booster charge assembly that is fitted with a small HMX shape charge. This high energy primer is designed to be compatible and reliable for firing bulk emulsions, including those with high percentages of urea inhibition to combat reactive ground. Up to 1000 detonators may be programmed in 1ms increments up to 1500ms. The system is controlled by a digital firing panel that can be used with either a wired or wireless trigger.  The system enables high temperature and/or reactive ground sites to utilize in-hole delay initiation and realize the associated performance benefits. Conclusions and Future Work 1] The HMX based electronic initiation system permits bottom in-hole delaying in ground temperatures above 80°C (175°F). As compared to top priming and surface delaying, in-hole bottom delaying is known to improve floor quality, muckpile fragmentation uniformity and reduce oversize. 2] Field evaluation of the HMX initiation system at the Lihir Mine is continuing. 3] Work on the next generation of the HMX initiation system is underway and will bring with it expanded application range and flexibility. 

Oct 1, 2024

By T. G. Joseph, M. J. Bolster

ABSTRACT This paper explores passive seismic measurement as an alternative, nonintrusive approach to conducting annual brake testing on surface mine sites. Dictated by the test site location, this evaluation adhered to the brake testing procedure as per British Columbia occupational health and safety regulations. Results showed excellent correlation to those reported via conventional practice: Comparing stopping distance, time, and velocity for the proposed instantaneous passive seismic versus conventional approaches, less than a 0.5% variance was evident. A viable alternative, the passive seismic approach, allowed an entire fleet of trucks to be sequentially evaluated for annual brake testing without disrupting operations by installing mechanical testing equipment.

Jan 1, 2012

By R. C. A. Thurston

AT A FATIGUE SESSION organised by the A.S.T.M. in 1949, R. E. Peterson presented a brief introductory paper ( 1) in which lie referred to a discussion on the fatigue of metals which took place in England in 1849, and then proceeded to review some of the subsequent researches concerning the mechanism of fatigue. In the course of the review, he discussed metallograpl1ic studies with single crystals and polycrystalline materials, studies with X-ray methods, and the application of the electron microscope. During that hundred-year period considerable progress was made toward a better under-standing of the nature of fatigue, although it is probable that even greater attention was directed to the more practical aspects of the problem, such as the effects of notches, temperature, corrosion, surface treatment, residual stresses, and so on. Since then there has been an appreciable acceleration in the tempo of the fundamental work, partly influenced by the rapid development of the theory of dislocations, with the result that our knowledge of the mechanism of slip, the initiation of fatigue cracks, and their subsequent propagation, has still further advanced, although it is by no means complete as yet. The present paper is an attempt to out-line the more recent developments in these basic studies, to correlate them when possible, and to draw attention to those directions in which research might profitably be pursued.

Jan 1, 1957