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By T Salman

The construction and use of the B.E.T. (gas adsorption) apparatus is described. Examples are given for the determination of large and small surface areas using nitrogen and krypton. Introduction A NY study of the milling of ores from crushing to grinding, classification, and concentration and finally dewatering of the products involves solid particles which are either in contact with a gas or a liquid phase. The surface area of the solid and its characteristics constitute important parameters in all mineral dressing operations. The success of any particular operation is dependent on the interaction of the surface of the solid particles with the gas or the liquid phase. Particle size and specific surface (surface area per unit weight) continue to be important parameters in the flotation research associated with the adsorption of collector molecules or ions on mineral particles, as in the early years of mineral dressing research (1). In order to understand the mechanism of the flotation process, it is essential that the surface properties of the adsorbent be known.

Jan 1, 1965

By N. Haghdadi, D. M. Maijer, A. B. Phillion

B206 is a recently-developed high-strength Al-Cu casting alloy with reduced Ti and Fe, as compared to the well-known AA 206 alloy, for improved hot tearing resistance. In the current study, the solidification kinetics of this alloy as a function of cooling rate from 1 to 15 K/min were studied using differential scanning calorimetry (DSC) and microscopy. Specifically, the evolution in fraction solid, grain size, and secondary dendrite arm spacing have been characterized. The DSC results show the occurrence of three peaks during cooling from the liquid state, which are related to the formation of primary aluminum, a pre-eutectic intermetallic, and the eutectic phases. Thermal analysis also indicates that while the liquidus temperature is not sensitive to the cooling rate, the temperatures at which the pre-eutectic and eutectic phases form are strongly coupled to the rate of heat extraction. A decrease in the latter temperatures was observed when the rate of solidification was increased, leading to a lengthening of the freezing range of the primary phase. The results will be useful for improving B206 casting processes, specifically through modification of mould cooling conditions.

Jan 1, 2014

By M. Özer, F. Boylu, G. Önal

In this study, the fine coal waste subjected to the experiments is taken from the waste stockpile of Soma Coal Plant. The possibilities of its evaluation and the production of clean coal were investigated. For this purpose, Reichert Coal Spiral and Shaking Table are used. The minus 1 mm coal waste includes 60.43% ash and 50% minus 38 micron material by weight. The microscopic observations of the screen fractions were shown that the clay minerals are in fine sizes and the coarser size fractions contain silica and carbonate minerals as ash forming materials. The tests were conducted after desliming. The commercial grade clean coal product containing 29-35% ash with a calorific value of 3800-4200 kcal/kg (15.91-17.58 MJ/kg) was obtained by gravity methods.

Jan 1, 2004

By Tatyana Alexandrova

The problem of processing refractory (rebellious) gold ores is important for all the countries involved in recovering precious metals from ores. Technological aspects of processing precious metal ores are examined in two respects: enhancing gold recovery from double refractory ores; and using carbonaceous ores on a production scale. The dispersed carbonaceous matter (DCM) present in concentrates causes the adsorption of [Au(CN)2]- complex on their surface during cyanidation process. Depending on the degree of graphitization and the organic carbon content in DCM (including kerogens and bitumen), the technology used to recover precious metals varies considerably. The problem of processing refractory (rebellious) gold ores is important for all the countries involved in recovering precious metals from ores. Depending on the degree of graphitization and the organic carbon content in DCM (including kerogens and bitumen), the technology used to recover precious metals varies considerably. The possibility of rare metals recovery, including rhenium, from black-shale rocks, has been examined. Comparative assessment of analytical methods of rare metals detecting has been carried out. It has been proved that neutron activation analysis is a promising technique. It has been shown that colloid-salt fraction (nanofraction) with particle size less than 1000 nm makes up to 3 wt% of black shale samples and is extracted by water under special conditions. The use of water instead of chemically active reagents provides insolubility of the mineral matrix and fully reflects the colloid-salt element of the samples. To sum up, the justification of the choice of technology for processing of carbon-bearing ores is based on examining the type of carbonaceous matter and its adsorption behavior. When the content of carbon of high degree of metamorphism is considerable, it is possible to recover platinum group elements and rare elements from this type of ores. The obtained results predetermine the general guidelines for creating new methods and techniques of processing carbonaceous material for integral development of solid minerals in the mining and oilfield areas of Russia.

Jan 1, 2016

By J. Walenzyk

This report investigates the limited use of super large backhoes in surface mines around the world. The demand for super large (> 700 t) hydraulic excavators is rising and most of the machines are sold as front shovel (FS) application. Despite advantages in faster cycle times super large backhoe (BH) machines are a minority (ca. 1% of the total machine population). This investigation is based upon the comparison between the volumes available to the BH and FS in one block and before the machine needs to move. The working conditions are created with standard parameters as given by Original Equipment Manufacturers of hydraulic excavators regarding bench height, angle, and material density. The travel amount of both machine types is derived from these volumes and compared. Furthermore, the travel amount of super large BHs is compared to the travel amount of smaller mining BHs and evaluated based on attachment length and bucket size. The calculations conclude that the volume of material recoverable in a single spot is about 75% higher for FSs. This leads to an increased travel for BHs. The combination of both the increased appearance of electrical driven machines (in the class of > 700 t excavators) and the travel amount lead to a high risk of damaging the cable or the excavator. Enlarged wear on the travelling parts is also attended by the higher travelling. A direct comparison of commonly found working set ups shows that the ratio between volumes is 32% which leads to an increased travel amount. In comparison with a 250 t BH, the calculation shows that the smaller BH is able to reach nearly 50% of the volume of the super large BHs. The main reason for this is the respectively high reach on smaller machines which, combined with other factors, leads to a significantly higher number of BHs in lighter classes.

Aug 1, 2013

By F. Musuka, D. Jenkins, A. Keyes

BHP Olympic Dam operates a Direct-to-Blister copper flash smelting Furnace (DBF) and an Electric Slag Cleaning Furnace (ESCF). Tapping blister copper from these furnaces via tapholes is a routine task carried out by trained personnel. Blister tapping is a high-risk activity with personnel operating in close proximity to molten metal. BHP’s risk management framework has identified taphole integrity as key to managing the potential for loss of molten metal containment and molten metal – water steam explosion, both of which have the potential to cause multiple fatalities. As part of the focus on managing this risk, since 2017, a dedicated Taphole Development Team has been embedded in the operation to run an accelerated improvement program focused on safely and sustainably embedding an improved taphole design with greater integrity. The program of works includes selecting and testing of new materials as well as improving operating discipline by collaborating with tapping personnel to convert their knowledge into codified condition monitoring and operating strategies. Computational fluid dynamics (CFD) is being used to derive critical risk controls, and to develop live-alerts to infer excessive refractory insert wear. To date, improving DBF blister taphole mudgun clay has led to more consistent drilling depths and subsequently reduced oxygen lancing requirements, resulting in improvements in taphole insert service life. On the ESCF, insert performance testing and development of a new taphole condition monitoring strategy, is being used to increase taphole insert tonnages to more sustainable levels. Operations personnel have been closely involved in different phases of the change management, this has led to standardization of tapping practices for both furnaces, and improved ownership of the proposed changes. The paper discusses the maturity in taphole integrity risk management as a result of recent and ongoing developments. It then provides an overview of future taphole developments proposed at Olympic Dam. INTRODUCTION Tapping operations at Olympic Dam and learning from significant events The Direct-to-Blister furnace (DBF) at Olympic Dam was built with a conventional design blister taphole, which was designed for manual oxygen lancing and clay stopper bar plugging tapping operations (Campbell, 2005). Manual tapping is a high-risk activity, where personnel work in close proximity to molten metal, and molten metal personal protective clothing and equipment must be used. Opening tapholes by oxygen lancing is a skilled activity and unintentional damage to the taphole inserts can occur. Since 2008, a Mudgun and Drill unit has been developed and trialled and is now in use on the DBF blister tapholes, to remove personnel from the line of fire when opening and closing tapholes. This has the additional benefit of reducing lancing damage to taphole inserts. A new taphole design labelled the Modular Blister Taphole (MBTH) was developed at Olympic Dam for the Mudgun and Drill operation. The intent of the design was for mudgun clay to fill the entire tapping channel when plugging after a tap. The drill would then drill through this clay plug to open the taphole.

Jan 1, 2019

"In mills, metallurgical efficiency is important in every step of the operation through to the tails. Different problems which hinder metallurgical efficiency exist in different mills. One such problem occurred in the Bralorne mill at the tailings end of the circuit, where the washing efficiency of the filters was so low that serious losses in dissolved gold occurred.The new cyanide plant at Bralorne went on stream in August 1961. Test work done showed that: a flowsheet of grinding in water, jigging, thickening, agitating, followed by double filtration, gave satisfactory results and was more economical than a counter current plant. Two filters, 141 x 161, with approximately 700 square feet of filtering surface on each, were purchased and installed in series. Test work showed that this was ample filtering area for 500 tons per day.When the plant started up a density of 45% solids was maintained in the agitators, and a 20 ounce cotton dl1ck was used on the filters. Vacuum was between 23 - 25 inches. Under these conditions the filters would not work and only picked up a very slight skim of pulp. Various speeds were experimented with, 4 minutes per revolution being the most efficient. At this speed the thickness of the pulp on the filters increased to about 1/8”• It was therefore quite apparent that, under these conditions, the filters would not handle very much tonnage and the mill tonnage would have to be reduced drastically until the problem was solved."

Jan 1, 1967

By Chris G. Dobson

Introduction The Britannia mine is at Britannia Beach, on Howe sound, approximately thirty miles from Vancouver. The first claims were staked in 1898, and a local company was formed at that time to develop them. In 1904, Mr. Grant B. Schley became actively interested in the property and in the following year the Britannia Mining and Smelting Company, Limited, was incorporated to operate it. This Company was taken over a few years later by the Howe Sound Company, Limited. The mine comprises five more or less separate ore-bodies, which have produced approximately 20,000,000 tons of ore to date. The East Bluff ore-body, with which the present paper deals, is well suited to large-scale mining by means of carefully placed powder blasts. It covers approximately an acre and lies in the slate footwall, in a bay produced by a fault. The hanging-wall side, on the west, forms the face of the Bluff glory-hole, which extends to the 1,200 level. A portion of this ore was available for breaking into this old glory-hole, below which four bulldoze chambers could quickly be built. Mining of this block is complicated by a very soft footwall, which 'runs' badly when broken. In stoping, care is taken to guard against the hazard of dilution by deliberately leaving a small portion of ore on the footwall. Some of this will undoubtedly be lost, but it is hoped to recover a fair amount of it after the major drawing is completed. The deposit occurs in a greenstone which has been highly silicified following brecciation. The chief minerals are chalcopyrite, sphalerite, and pyrite. Concentrates of copper, zinc, and pyrite are made at the mill. The average grade of ore runs 0.7 per cent copper, 1.5 per cent zinc, and 0.03 oz. gold per ton. The rock, which is practically a chert, is extremely hard, but shatters well. Both in stoping and drifting, holes must be closely spaced and powder used generously. Development When development work started in the East Bluff, there were no raises and only one drift on each level in this section of the mine. After blocking out the ore by thorough diamond drilling, a production of two thousand tons per day was set as a goal. To obtain this tonnage from so small an area required a great deal of carefully planned and well timed development work.

Jan 1, 1935

By C. Zangerl, T. Strauhal, S. Perzlmeier, M. Holzmann

"In high mountainous regions, deep-seated rock slides are often observed in foliated metamorphic rocks such as paragneisses, micaschists and phyllites. Given that comprehensive investigations of deepseated rock slides are extraordinary costly and therefore are rare, most studies are related to investigations in the surroundings of infrastructures and human settlements. In the framework of this study there is an excellent opportunity to gain new insights in the fundamental processes and mechanisms of slowly moving deep-seated rock slides from a case study in the surrounding of a large dam reservoir in Austria. New fundamentals for comprehensive slope stability analyses and hazard assessments and sound prognoses focussing on the long-term stability and deformation behaviour of slopes under changing boundary conditions (e.g. impounding of a reservoir) and/or concepts for mitigation measures can be obtained. Within this contribution, geological field surveys, deformation monitoring, geophysical and drilling data were analysed and presented. Based on the compiled and analysed data, some key-properties of the rock slide will be presented, whereby special attention will be given on the geometry and internal structure, the slope kinematics, as well as hydrogeological and geomechanical aspects.INTRODUCTIONIn high mountainous regions, deep-seated rock slides are often encountered in highly foliated metamorphic rocks such as paragneisses, micaschists and phyllites (Agliardi et al. 2012). Critical situations may occur when deep-seated rock slides fail in a rapid manner characterised by very high sliding velocities, and/or when they develop into long run-out rock avalanches. However, many rock slides in foliated crystalline rock masses either do not move at high velocities nor do they accelerate seriously and form extremely rapid slides. Displacement rates in the range of a few millimetres or centimetres per year are common for this type of rock slide (Bonzanigo et al. 2007, Tentschert 1998, Watson et al. 2007). Nevertheless, some case studies show an activity behaviour characterised by acceleration phases reaching velocities of even metres per day. However a slope collapse is not expected and these slopes decelerate to much lower base activities. The trigger for these phases can be manifold and include heavy rainfall and snow melt, initial reservoir impounding and water level fluctuations, changes in the slope’s equilibrium state due to antecedent slow deformation processes, ongoing erosion processes along the toe of the slope, and others (Zangerl et al. 2010)."

Jan 1, 2015

By J. W. Hendry

"This paper will discuss the application of tools and the evolution of computer-assisted procedures in the production planning process at Quintett e Coal Limited (QCL). In 1986, QCL produced 5.3 Mt of clean coal from their surface mining operation located in north eastern British Columbia. The structural complexity of the sedimentary deposit and high rate of mining necessitate the consideration of large amounts of geological information which continually updates the interpretation. There are multiple unit operations required during the process of mining through a given multi-seam sequence, which results in many interdependent faces, and multiple iterations of scheduling sequences in order to satisfy a given set of objectives. In order to facilitate these activities in a timely fashion, it was recognized that a computer systems' capability needed to be developed which could increase the efficiency of information input, manipulation and output. IntroductionQuintette Coal Limited (QCL) has been operating a large metallurgical open pit coal mine in northeastern British Columbia, since 1982. The mine produced 5.3 Mt of clean coal in 1986 for export to Japan. Throughout the start-up period and the subsequent build -up of production levels, it became evident that the primary producing area was comprised of extremely complex faulted structures. This has resulted in development and modification of specialized mining methods employed to effectively recover the resource. Similarly, the planning and engineering techniques employed have been evolved over the same period of time. The implementation of computerized methods has been one of the major developments in this process, including geology interpretation, modelling, reserve definition, quantification, production planning and scheduling, and graphical plan presentation. These capabilities have been employed, in various forms, for project scale feasibility work and long range planning for some time, however, the use of computer tools for short-term, detailed production planning of a complex mining environment presents a different set of problems. It is hoped that a presentation of the current state of evolution and future plan s for development will be of interest to organizations considering implementation of a similar system."

Jan 1, 1988

By Li Chongyang, Liu Baolan, Jia Xiaolin, Li Suping

An Al/Al2O3 gradient coating applied on a heat-resistant stainless steel was prepared through a slurry process by using aluminum and ?-Al2O3 powders as the transition filler material, alpha alumina as the surface coating material, aluminum dihydrogen phosphate as the binder, and sodium molybdate as the corrosion inhibitor. The effects of heat treatment temperature, adhesive/filler ratio and ?-Al2O3 content on the bonding strength, microhardness and thermal shock resistance were investigated. The crystal phase and microstructure were characterized by XRD and SEM. The results indicated that the composition of the coating changed continuously from surface to coating-substrate interface. The coating could offer high bonding strength and good thermal shock resistance when heat treated at 700°C.

Jan 1, 2010

By T. Maio

Twelve years ago, Kennecott Utah Copper modernized its Refinery in conjunction with the modernization of the Kennecott Smelter with the latest flash smelting and flash converting technologies. The Refinery modernization consisted of installation of new polymer concrete cells, installation of KIDD TPS (total production stripping) system, installation of automated materials handling system, and the construction of a new hydrometallurgical slimes treatment process and precious metals plant. This paper outlines the Refinery operations and process improvements. Also presented are the newly implemented technologies and operating results of one of the world' s largest and most modern electrolytic copper refineries.

Jan 1, 2007

By T. Crivits, I. Bellemans, K. Verbeken

In the metallurgical industry, furnace cooling is often employed to enhance furnace lifetime. Hence, the pyrometallurgical phase comes in close contact with a non-air coolant. The proximity of the pyrometallurgical phases to the coolants may lead to dangerous situations. In case of a breach of the cooling circuit, the contact between a hot and a cold liquid may cause a vapour explosion. The outcome of this vapour explosion includes a pressure wave which could result in damage to the furnace, bodily injuries or even casualties. To prevent such dramatic events, the origin of vapour explosions is currently being studied in more detail. For this purpose, OpenFOAM was used to perform Computational Fluid Dynamics (CFD) simulations. In a first step, simulations were run to get a better idea of the influence of the compressibility on the simulations. The obtained results help in getting a better insight on the need of computational power, and possible numerical errors using compressible or incompressible solvers in future simulations. In a second step, systems without vapour explosions were simulated and compared to experimental results with mercury and aluminum. INTRODUCTION Humanity started using metals for tools around the Chalcolitic (~7400 cal BC), when copper was melted in small furnaces (Radivojevic, Rehren, Farid, Pernicka, & Camurcouglu, 2017). Nowadays, metallurgy has grown into a major industry and it has become impossible to imagine society without metals. In the pyrometallurgical industry, coolants (low temperature liquids, for example water) and pyrometallurgical phases (high temperature liquids, such as slags, mattes and alloys) are typically present in close proximity of each other. The interaction between these two phases can have catastrophic consequences (Tveit et al., 2008; Ferguson & Zsamboky, 2017). A vapour explosion may occur as the consequence of the rapid evaporation and expansion of the coolant. Whereas the volume of a gas increases linearly with the temperature (approximately a factor four by heating from 100°C to 1300°C), a simple calculation of the ratio of the two specific volumes shows that evaporation causes the volume of water to increase by a factor of 1700 at 100°C and ambient pressure (Table 1 and equation (1)), a number that was also found in literature (George, Nexhip, George-Kennedy, Foster, & Walton, 2006). The volume change occurs so fast that it resembles an explosion, hence the name vapour explosion. Such an explosion at industrial scale can cause economical losses, bodily injuries or even fatalities.

Jan 1, 2019

By C. F. Harris

Following the initial development of the zinc-lead blast furnace, efforts have been directed both at increasing the scope of the process and increasing the cash return. The paper reviews the process developments which enable the process to smelt efficiently a range of material which encompasses high-grade zinc sulphide concentrates. mixed concentrates, Waelz oxide, zinc ashes and other materials blended to give a furnace feed ranging from 25 to 65% zinc and from 1 to 25% lead, with a copper-lead ratio exceeding 1 to 8. The paper also reviews the process developments which have enabled the capacity of a furnace and condenser system of standard size to be boosted from 30,000 to 80,000 tonnes/annum. The benefits achieved are used as a justification for continuation of the development of the zinc-lead blast furnace. Predictions are made of the benefits expected from further developments.

Jan 1, 1979

By M. C. Villeneuve, P. A. Siratovich

We present an integrated analysis of laboratory-based thermally induced fracturing and results of numerical models to give insight to the role of thermal shock fracture on geothermal reservoir rocks. Thermal stimulation is a reservoir permeability enhancement technique applied to commercial geothermal reservoir rocks to enhance fluid injection capabilities for spent power plant working fluids. The process is well known to enhance permeability but the thermodynamic and physical constraints of the process are less certain. In an attempt to constrain the interaction and the ideal conditions that lead to permeability enhancement, experimental procedures were carried out to mimic the conditions that a reservoir rock would experience during a thermal stimulation using temperature differentials ranging from 50-300°C. Samples underwent such thermal gradients under controlled laboratory conditions and were characterized for the changes to permeability, porosity, ultrasonic velocities, dynamic elastic moduli and petrological changes. The thermal stimulation was simulated in a FLAC2D thermal numerical model to investigate the nature of the thermally induced changes in the sample. The development of this model also allows us to investigate the relationship between geological characteristics and the ability to thermally stimulate any type of rock. The results indicate that numerical thermal shocking experiments are corroborated by laboratory-based results. The implication of this study is that the refined numerical models present an insight to the conditions and constraints under which thermal stimulation can prove to enhance permeability that could not be gained through purely laboratory-based studies.

Jan 1, 2015

By J. P. Sims

Abstract - Ultramafic to mafic igneous intrusions of the Las Aguilas district form part of a belt of generally mafic plutonic bodies within medium- and high-grade early Paleozoic metamorphic rocks in the southern Sierras Pampeanas region, Province of San Luis. The intrusions host the largest known nickel sulfide resource in Argentina and contain significant Cu, Co and PGE mineralization (2.2 Mt at 0.5% Ni, 0.5% Cu, 0.035% Co). Sulfides at Las Aguilas Este, one of two principal mineralized zones, are hosted by a body comprising subvertically dipping units of predominantly orthopyroxenite and melanorite cumulate, with lesser dunite, harzburgite, norite, leuconorite, and amphibolite. The units are zoned horizontally from ultramafic to mafic compositions, representing primary magmatic zonation away from an original base or side of the intrusion. Intercumulus nettextured and disseminated aggregates of pyrrhotite-chalcopyrite-pentlandite are concentrated in the peridotitic zones and extend into melanorite. Whole rock major and trace element compositions, and olivine chemistry, indicate that the parent magma was gabbroic/basaltic with 100 (Mg/Mg+Fe) near 59, and resembles tholeiitic magmas generated in subduction-related arc, or back-arc settings. Unusually aluminous Cr-bearing spinel is compositionally similar to those in some synorogenic mafic/ultramafic plutons in magmatic arc settings. Relatively Ni-depleted olivines and low Cu/Pd ratios are indicative of magmatic sulfide segregation early in the crystallization of the magma. Early orthopyroxene saturation and virtual lack of clinopyroxene, in conjunction with sulfur isotope values up to +6.6 ‰, spinel compositions, and presence of graphite, phlogopite and magmatic hornblende, all attest to probable crustal contamination of the parent magma. Assimilation of crustal sulfur may have been crucial in the early attainment of sulfide saturation and resultant formation of magmatic Ni-Cu sulfide mineralization. Fabrics, textures and mineralogy of the intrusions and country rocks and U-Pb zircon dating indicate syntectonic-synmetamorphic emplacement at 478±6 Ma during the Famatinian (Ordovician) orogeny. Minor to locally significant recrystallization and deformation of mafic-ultramafic rocks and redistribution of sulfides and PGE occurred during and following the Famatinian orogeny. The Las Aguilas intrusion is one of several tholeiitic mafic-ultramafic intrusive complexes within an Ordovician arc - back-arc system in the Sierras Pampeanas. Aeromagnetic datasets and regional mapping suggest there is further potential for intrusion-hosted Ni-Cu mineralization along this eroded magmatic arc.

Jan 1, 1999

By W. H. Mathews

"The Hardie group of cinnabar claims is in the interior of British Columbia; 25 miles northwest of the city of Kamloops. It is one of a number of mercury; properties scattered along a north trending belt 20 miles long and up to 5; miles wide. In all but one of these properties cinnabar is associated with; dolomite veinlets in zones of carbonate alteration in bedded rocks of Triassic; and Cretaceous (?) age; or in intrusives cutting these bedded rocks. No dolomite alteration or cinnabar mineralization is known in the undoubted Tertiary rocks adjacent to the mercury belt.The mercury showings of the Hardie group lie for the most part in a granitic stock cutting Cretaceous (?) volcanics. The rock in this intrusive shows marked variations in texture and has been described in earlier reports as granite and granodiorice, granite porphyry, and trachyte or dacite porphyry. At Hardie mountain the cinnabar mineralization, unlike that of the other properties, is associated with a fine-grained, almost chalcedoni c, quartz; carbonates, though present, are of minor importance. Some of the most interesting showings are found in an adit in the southeastern part of the property where cinnabar mineralization shows a very distinct structural but not a genetic relationship to a brown porphyry dyke 2 to 8 feet wide cutting a phase of the stock that may best be described as aplitic"

Jan 1, 1954

By C R. Evans

Whole-rock and muscovite potassium-argon dates from selected low-grade metamorphic rocks of Precambrian age in the Canadian Rocky Mountains near Jasper, Alberta, were obtained to ascertain the age of the source terrain and the age of the metamorphism. Ten argillites gave whole-rock dates ranging from 270 to 485 million years, dates which are apparently inter-mediate between the age of the source material and that of the metamorphism. "Up-dating" increases with the degree of orientation of muscovite in the cleavage plane, and with the ratio of the muscovite in the cleavage plane to that in the plane of the bedding. Detrital muscovite from four arenaceous rocks gave dates ranging from 1,050 to 1,780 million years. "Updating" increases with decreasing grain size, so that, within the range investigated, the cube of the median diameter (¢) of the muscovite is apparently proportional to the radiometric date.

Jan 1, 1964

By G. R. Guillet

"Bricks made from local Paleozoic shales, and floor and wall tiles made from imported clays, both established record production volumes in 1985 and are the strongest segments of Ontario's clay products industries. However, renewed interest in traditional materials also supports a good market for clay flower pots and flu e liners, and innovative processing studies are showing promise for possible new production of clay roofing tiles. This paper reviews the highlights of a comprehensive study of Ontario's clay products industries, completed in 1986. IntroductionFor some years now, Ontario's clay products industries have been unspectacular in their attempt to cope with the recent recession and the impact of alternative materials. But a strong demand for bricks in recent years has done much to dispel the gloom. Bricks, drainage tiles, sewer pipes, flue liners, structural and partition tiles, and flower pots have been commonly referred to as ""heavy"" clay products, and they have been based largely on local clays and shales. To this list might be added expanded aggregate and mineral wool. Clay refractories, sanitary ware, electrical porcelain, art pottery, and floor and wall tiles are not considered heavy clay products, and are commonly made from a variety of ceramic materials, many of which are imported.Production facilities for heavy clay products often began in Ontario as small family enterprises, using whatever clay was available locally to supply the local market with building bricks and other clay products needed for construction. Improved road systems increased the market range for these plant s, and new technology and industry standards resulted in gradual upgrading and consolidation of them as traced in Table I"

Jan 1, 1988

By A. L. Hinde, H. Dong, J. T. Kalala

"The High Pressure Grinding Roll (HPGR) is gaining acceptance in the mineral processing industry and has become a competitive technology in reducing the specific energy consumption in Mineral processing plants. The amount of samples required for HPGR amenability testwork and HPGR wear tests is usually high and often cannot be available at early stage of projects were only a few drill cores are available.Although HPGR was initiated from small scale piston die compression tests, the development of small scale piston die test to predict the performance of HPGR has been slow.The objectives of this paper was to present the designs, operating procedure of piston-die press and operating conditions which have resulted in similar particle size distribution obtained from a piston die test and HPGR Labwal unit starting from the same feed size distribution. Testwork were conducted using a 2 MN piston-die press and a Labwal HPGR unit on major South African ore types, viz, gold, platinum and iron ores. The results obtained show that piston-die test can generate data to predict energy consumption, product size distribution, and even to evaluate the edge effect."

Jan 1, 2012