Search Documents

By Clara María Lamus Molina

The following minerals found in the residual black sands from gold mining in El Bagre Antioquia (Colombia) were identified as having major economic interest: Ilmenite (FeTiO3), with an average of 49% of TiO2, frequently altered presenting crowns; lamellaes of rutile and alteration textures; titanomagnetite with up to 25% of TiO2; magnetite (Fe3O4) in individual grains or associated with others minerals as hematite and ferromagnesian silicates rutile (TiO2) with considerable quantities of Nb2O5(0.1-3.7%Wt); zircon (ZrSiO4) with 66%Wt of ZrO2 and monazite with an average of 63.43%Wt of REE, this frequently associated to xenotime and thorite forming textures as little drops. Analysis in EPMA and SEM/EDS showed percentages of minor elements and traces, thereby clearly establishing the applications of these minerals in diverse industries. Furthermore, a detailed granumetric study of the different minerals and textural relationships among them also allowed for establishing the basis for possible processing and exploitation.

Jan 1, 2006

By W. H. Yong

The molybdenum ores currently utilized in China are mostly molybdenum sulfide ores, whereas oxidized molybdenum ores have not been exploited and utilized efficiently. The aim of this article is to study the applied mineralogy of an intergrown iron-molybdenum oxidized ore in order to provide a mineralogical basis for the ore beneficiation research. The ore occurred in a surface oxidized zone seam and contained 23.65% Fe2O3 and 1.58% Mo. Various characterization techniques were employed to study the chemical composition and mineral composition of the ore, the particle size distribution of the minerals in the ore, and the tex-ture and structure of the ore. The results showed that the iron-molybdenum ore occurred in a wet, soft and earthy state. The ore was composed mainly of several oxidized minerals and colloidal min-erals, including wulfenite, barite, limonite and quartz. Wulfenite was one of the major and stable components in the ore and occurred as a separate mineral. Wulfenite, barite and quartz were granu-lar minerals with particle size ranging from fine to coarse but mainly in the fine particle range. Li-monite showed a crust and honeycomb-like colloidal state and composed the framework in the ore for the formation of the other minerals. They filled the pores in the framework and the size of the pores affected the size of the minerals formed in the pores and hence the recovery of wulfenite in ore beneficiation. According to the applied mineralogical properties of the oxidized molybdenum ore, a promising ore beneficiation process was proposed as follow Magnetic separation should be carried out first to separate the magnetic iron minerals and then the molybdenum mineral will be recovered by gravity concentration or a combination process of gravity concentration and flotation, depending on the distribution of the molybdenum mineral in the product of the magnetic separation.

Jan 1, 2014

By Bojcevski D

The deportment and textural relationships of silver bearing phases are key characteristics in understanding the behaviour of silver ores in flotation tests or processing plants. These characteristics are however difficult to define and quantif

Jan 1, 1997

By F. M. Nakla

Various methods of Applied Mineralogy were used for determining the nature and composition of products yielded by flotation tests for Maghara coal beneficiation. Coal samples obtained from the Sa fa mine in Northern Sinai, Egypt, were crushed, sieved, &apos;and <32 mesh size fraction was cleaned by froth flotation. Experiments were conducted to determine the effect of certain parameters on beneficiation of Maghara coal by flotation. The investigated factors included nature of frothing and/or collecting reagents, pH value of the medium, particle size distribution in the head sample, and pulp density of the coal slurry. The quality of head samples, coal concentrates, and tailing products were determined by chemical analysis, microscopic study, x-ray diffraction analysis, and occasionally by infrared (IR) absorption spectroscopy.

Jan 1, 1989

By S Meffre, A E. Fallick, K Zaw, I T. Graham, G Giuliani

Dispersed gem corundum is mined from placers, commonly from basalt fields, as occurs along eastern Australian and Asian continental margins. New laser ablation inductively coupled plasma mass spectrometry analysis (LA-ICP-MS) of Australian corundum allows genetic distinctions among these suites and gives clues to their primary lithospheric sources prior to basaltic delivery. Bimodal corundum suites at Barrington Tops, Cudgegong-Gulgong-Macquarie River and Yarrowitch, New South Wales (NSW), include lower Ga, higher Mg æmetamorphicÆ and higher Ga, lower Mg æmagmaticÆ groups. The Barrington Tops æmetamorphicÆ corundum is more Fe-rich (av 4500 - 7100 ppm) than Cudgegong- Macquarie River equivalents (av Fe 1800 - 2100 ppm). Yarrowitch corundum is relatively low in Fe, Ti and Cr. Along with other eastern Australian data (north-east Tasmania; New England, NSW) and from gem fields elsewhere, the combined trace element and O isotope data, reveal considerable geographic and genetic variations within the corundum suites. A few corundum groups contain noticeable Be, Sn, Ta, Nb, a particular genetic message that also precludes easy distinction of treated corundum in the gem trade. Expanding geochemical, inclusion and geochronological data on gem corundum hold promise for characterising derivative gem corundum on both geographic and genetic features.

Jan 1, 2008

By Panagiota Tsolis-Katagas, Basilios Tsikouras, Tassos A. Grammatikopoulos, C. Katagas

"Mineralogical techniques including microscopic methods, reflected and transmitted light microscopy, Cathodoluminescence (CL) and Scanning Electron Microscopy equipped with an Energy Dispersive Spectrometer (SEM-EDS), are useful in determining the quality of industrial minerals. They are essential for studying ores and metallurgical products including the evaluation of physical characteristics of the mineral, paragenetic relationships, associations with possible deleterious contaminants (e.g., sulphides), spatial distribution within the ore zones and liberation characteristics. The methods are inexpensive, and provide quick identification and distinction among the industrial minerals and the gangue minerals in a section. Additionally, SEM is necessary to reveal complex textural sequences and 3-D measurements of minerals and quick semi-quantitative analysis.Common analytical methods include Electron Microprobe Analyses (EMPA) and Whole Rock Analysis (WRA) (commonly with XRF and ICP) for major and trace elements. The EMPA analyses of industrial minerals provide information on the purity of the analyzed grains as opposed to the bulk chemical analyses that may be misleading due to contamination by other associated common “gangue” minerals. These techniques have been implemented for the case studies of wollastonite, V-magnetite and muscovite. Therefore, these methods can provide extremely useful information and lead to the implementation of a successful pilot-testing programme.MINERALOGICAL EVALUATION OF DEPOSITSDespite their considerable and increasing economic importance, industrial mineral deposits have traditionally been neglected by economic geologists, and are only rarely the subject of the detailed analysis widely lavished on metallic mineralization. Moreover, in that they generally represent concentrations of “normal” rock-forming minerals, albeit commonly with particular textural and/or geochemical features, they have tended to fall between the mainstream of petrogenetic studies and mineral deposit research (Grammatikopoulos 1999). For many industrial minerals, little attention has been paid to the factors responsible for their local concentration as large and high-grade bodies. This comparative neglect has particularly been the case for minerals such as talc and wollastonite, widespread in metamorphic rocks, in which they are reasonably interpreted as components of assemblages derived, respectively, from pelitic sediments, ultramafic igneous rocks and siliceous limestones."

Jan 1, 2003

By Susanne Pignolet-Brandom

Reflected light microscopy scanning electron microscope energy dispersive spectroscopic analysis and backscatter electron image and electron microprobe chemical analysis have been used to study lead sinter and lead blast furnace slag. These studies provide invaluable information on the phases present their intergrowths, and their chemical composition. Such information increases the understanding of the nature of pyrometallurgical processes and the behavior of minor elements during these metallurgical processes.

Jan 1, 1987

By A M. Hagni

Certain copper ores from the Nchanga Copper Mine in the northern Zambia Copperbelt are refractory with respect to conventional beneficiation techniques. This paper reviews recent study of those ores to determine their mineralogy, textures and nature of copper occurrence. Two suites of refractory ores were selected for study: 1.&nbsp; samples of stockpiled ores from an open pit, and 2.&nbsp; drill core samples from copper ores. Both sample suites are from the upper orebody at Nchanga and contain about 0.3 - 1.4 per cent copper as determined by atomic absorption, but they represent separate stratigraphic, mineralogical and beneficiation problems. Ore microscopic examination showed that fine-grained copper sulfides are totally lacking from both suites of refractory ores. Petrographic study found malachite in the refractory ores from the open pit, but that malachite probably is post-mine. The opaque mineralogy of the open pit refractory ores is dominated by goethite that occurs mostly as pseudomorphic grains after pyritohedral pyrite crystals that average 200 - 250 ¦m across. Haematite occurs as bands within or as outer shells of the goethite grains. Additional goethite occurs locally as finer-grained areas of exotic goethite. The opaque minerals in the drill core refractory ores are dominated by euhedral ilmenite crystals about 50 - 175 ¦m long. Anatase is the dominant opaque mineral in some drill core samples where it is largely pseudomorphic after ilmenite crystals. Goethite accompanies malachite in unusual drill core refractory ores that have experienced intense hydrothermal alteration. Thus, ore microscopy and petrography showed that fine-grained chalcopyrite and bornite and pre-mine malachite were not the causes of the refractory nature of the ores studied. Electron microprobe revealed that most of the copper occurred in solid solution within micas. Application of automated SEM techniques has provided a detailed understanding of the distribution of copper in these refractory ores.

Jan 1, 2008

By F Gervilla, J Laukkanen

The Kevitsa Ni-Cu-PGE deposit in northern Finland contains disseminated Ni-Cu-Fe sulfides, and platinum-group minerals (PGM). The 2.05 Ga-old ultramafic-mafic, funnel-shaped intrusion is intruded into a volcanosedimentary sequence. The major ore minerals are pentlandite, hexagonal pyrrhotite and troilite, chalcopyrite, cubanite and magnetite. Pyrrhotite and pentlandite are replaced by pyrite, millerite and heazelwoodite near the surface. Nickeline, maucherite and gersdorffite are locally abundant. A pilot feed sample of 575 t of the main orebody at Kevitsa had average grades 0.45 per cent Cu, 0.36 per cent Ni, 1.85 per cent S, 0.33 g/t Pt, 0.34 g/t Pd and 0.19 g/t Au, with 0.06 per cent Ni contained in silicates. Higher PGE contents (2 - 27 ppm) occur in a vertical N-S bearing fault zone. The PGM (n = 6022) mapped in specimens of four drill holes, consist of sperrylite 34.7 vol per cent, braggite and cooperite 18.5 vol per cent, geversite 17.2 vol per cent, moncheite 14.7 vol per cent, merenskyite 6.7 vol per cent, stibiopalladinite 4.3 vol per cent, sobolevskite 1.9 vol per cent, kotulskite 0.7 vol per cent, michenerite 0.6 vol per cent, keithconnite 0.3 vol per cent, rustenburgite 0.1 vol per cent, melonite, froodite, laurite together 0.1 vol per cent and only a few grains of sudburyite, irarsite, vysotskite, erlichmanite, hongishiite, Pt-Cu-alloys, three undefined Pd and Pt bismuthinides and antimonides and a Pd-Cu-bearing Pt-Ni-Fe sulfide. Most of the PGM, 62 per cent, are enclosed in silicates, 29 per cent are intergrown with sulfides, nine per cent are within sulfides. A portion of the PGE occurs in solid solution in sulfides and arsenides. Ni flotation yielded smelter-grade concentrates averaging 12.2 per cent nickel. The average sulfide Ni recovery is 78.8 per cent and total Ni recovery is 65.3 per cent. The average Pt is 10 g/t at 55 per cent recovery, Pd 7.7 g/t at 38 per cent recovery and Au 1.6 g/t at ten per cent recovery. Cu concentrates averaged 28.6 per cent Cu with an average recovery of 78 per cent and further 11 per cent in the nickel concentrate. The copper concentrate contains 4 g/t Au at 24 per cent recovery. The average Fe to MgO ratio 17.9 is well above the targeted minimum of 4.5. The pilot results show that the previously used TETA (triethylene tetramine) can be avoided and good quality, smelter-grade concentrates can be produced from the Kevitsa ore at economical levels of recovery by conventional flotation methods.

Jan 1, 2008

By J Leppinen, B Johanson, R Kalapudas, G McMahon

The Suurikuusikko gold deposit was discovered in 1987 in western Finnish Lapland, 54 km NNE from the town centre of KittilS in the volcanic belt of Central Lapland. It is hosted by tholeiitic basalts in a graphite-bearing albitite breccia. The ore is located in subvertical shear zones characterised by strong albitisation, carbonatisation and sulfidisation. The ore minerals consist of arsenopyrite, pyrite, chalcopyrite, sphalerite, tetrahedrite, bournonite and rutile. Small amounts of pyrrhotite, gersdorffite, jamesonite, bornite, gudmundite, tetrahedrite, stibnite, kermesite, berthierite and native Sb are also present. Gold occurs as invisible and as 1 - 2 ¦m size inclusions in arsenopyrite and pyrite, on their grain boundaries and in fractures. The average amount of gold leached by cyanide is 2.93 per cent. The æinvisibleÆ gold contents were studied in pyrite and arsenopyrite by electron microprobe analysis (EPMA) and secondary ion mass spectrometry (SIMS) at CANMET/ MTL. Gold element distribution images show zoned patterns both in pyrite and arsenopyrite. SIMS analyses range from 343 to 55 ppm Au in arsenopyrite and from 217 ppm down to 0.32 ppm (detection limit 478 ppb) Au in pyrite. EPMA results range from 939 to below the detection limit 24 ppm Au in arsenopyrite and from 267 ppm to below 22 ppm Au in pyrite. Recovery of the refractory gold ore was studied using grinding, flotation, bio-oxidation and cyanidation tests. A sulfide bulk concentrate containing 40 ppm Au was obtained by flotation at 90 per cent recovery (As content 5.5 per cent, S content 22 per cent, and mass recovery 15 per cent). The grinding fineness in flotation was P80 -100 to 120 ¦m. At the original fineness the cyanidation recovery from the concentrate was lower than ten per cent, after ultra-fine grinding P80 -10 to 2 ¦m the Au recovery was less than 17 per cent. After bio- oxidation, Au recovery of 95 per cent was obtained in carbon-in-leach (CIL). The bio-oxidation time was two weeks in laboratory test, but after regrinding the oxidation rate was faster and recovery of Au higher. However, the selected method for the mining to be started in summer 2008 is open pit mining and mineral processing methods sulfide flotation and pressure oxidation in an autoclave. The ore reserves were estimated 31 December 2007 as: Probable 18.2 Mt with 5.1 g/t Au, Indicated 5.4 Mt with 3.0 g/t Au and Inferred 10.8 Mt with 3.4 g/t Au. The production capacity will be 3000 t/day.

Jan 1, 2008

By M. Blagojev, R. Tomanec

"Studies reported in this paper used polymetallic Pb-Zn-Sb-As-(Ag, Au) ore from Dražnja, Kosovo. The ore is comparatively rich in Zn (6.56%) and Pb (2.87%), but with high rates of Sb and As. Conventional lead and zinc concentration by flotation produced galena and sphalerite rich concentrate with high recovery, but with excessive As and Sb. After chemical analyses, which could not detect the reason for the excessive elements, ore minerals were identified under the ore microscope, their texture characterized, and degree of liberation of useful minerals was assessed. Microscopy of the mineral concentrates revealed complex intergrowths of galena and marmatite minerals mostly with sulphosalt minerals (boulangerite, jamesonite and bournonite) and also with arsenopyrite mainly responsible for the unsatisfactory quality of the concentrate. These complex sulphosalts, among other things have similar behaviour during the flotation concentration, and in spite of their interlocking with galena, therefore inadequate liberation, sulphosalts remain in the lead concentrate. Microscopic analyses indicated that a better galena concentration product is possible with a higher rate of mineral liberation, and then by selective floc flotation of some sulphosalt minerals. Purpose of this work was to show that only chemical analysis is not sufficient, according to that we solved the problem by precise mineral identification and time consuming mineral liberation measurements. INTRODUCTION The polymetallic Pb-Zn-Sb-As-(Ag, Au) ore body of Dražnja, Kosovo, fairly rich in Zn (6.56%) and Pb (2.87%) was repeatedly explored and once even worked. Mineralization at Draznja was primarily represented by sphalerite, galenite and marcasite/pirite. Some sections comprise massive sulphides, and others are lower grade zones of semi-massive sphalerite/galena or marcasite/pyrite dominant sulphides. The ore body II was formed in the southern gallery in the structure Çukë – Lajthishtë (with content of 3.16% Pb and 7.31% Zn). Pb-Zn ore with increased content of As, Sb sulphosalts is not rare phenomenon in the world. While previously treated as unprofitable, economical uninteresting ore, today with development processing and new reagents (organic, ecologic), are the topic of scientific papers. The examination of Pb-Zn ore with high content of sulphosalts we find in deposits as: The hydrothermal vein deposit of Harja in the Baia Mare area, contain a wide variety of sulphosalts [Cook, N. & Damian, G., 1997]; also the deposits Fankou Mine in Guangdong Province and the Dachang Mine in Guangxi Province, where the flotation concentration of galena and jamesonite takes place [Runqing Liu et al. 2015], [Zhang Ting, Qin Wen-Qing, 2015];. On a samples from Tibet in China flotation separation test of galena and jamesonite was conducted [Sun Wei, Han Haisheng, Tao Hongbiao, Liu Runqing, 2015]. According to history of investigation, the mineralized area of Dražnja has a long history of exploration and possible exploitation activities [Slowey, Galen, 2009]. Recent workings were carried out in three stages through the 20th century."

Jan 1, 2018

By W. H. Pelton, P. G. Hallof

Outlining small pods of high-grade, massive sulfide, copper-zinc mineralization was the object of an intensive exploration program by Long Lac Mineral Exploration Ltd., near York Harbour, Newfoundland, Canada. Efforts to define the ore zones using surface dipole-dipole induced polarization techniques were not entirely successful due to the poor size-to-depth ratio of the targets and widespread disseminated mineralization. Additional information on the size and shape of the sulfide bodies was obtained by placing a current electrode directly within a mineralized drill intersection and systematically measuring the resultant potential on the ground surface. Some simple potential field sources were interpreted from the data and their validity has been shown by an extension to the underground workings.

Jan 1, 1973

By C. Chongo, L. Little, Q. Mclennan

Since commissioning in 2005, First Quantum Minerals’ Kansanshi Mine in Zambia has produced over three million tons of copper and 1.8 million ounces of gold from a deposit with highly varied copper mineralization. The processing plant is complex with three independent flotation circuits, gold gravity concentration, atmospheric and high pressure leaching, solvent extraction, and electro-winning. For the first ten years of operating the plant, copper mineralogy was inferred from total copper and acid soluble copper assays, and various misconceptions developed about the mineralogy which impacted operational strategy and project decisions. In 2015, an on-site mineralogy section was set up with an Automated Scanning Electron Microscope, the Zeiss MinScan. This instrument has provided detailed mineralogical data that have debunked some of the mineralogy myths that had developed, highlighting the key underlying issues affecting processing performance. This has enabled the development of projects targeting losses of specific copper minerals in defined size classes, unlocking significant value. This paper describes some of the early misconceptions around mineralogy at Kansanshi processing plant, outlining projects that have benefitted from understanding copper mineral distribution. Learnings from Kansanshi are to be applied at other FQM sites, with a similar mineralogy program being set up at the Cobre Panama project. INTRODUCTION The deposit Kansanshi Mine is located in the North Western Province of Zambia, and it has been the largest copper producer in Africa for over a decade. The deposit occurs within a broad northwest trending antiform that can be traced for 12 km, hosted in a zone of complicated faulting, abundant vein injection, breccia development and down-dropped rock units that lies within Kansanshi’s mining license. The copper mineralization within the deposit is predominantly vein-hosted, although some is strata-bound, occurring in thin bands and veinlets parallel to foliation, and some is disseminated associated with albite-carbonate alteration (Gray, 2015). Supergene enrichment has led to significant variety in the copper mineral speciation. This alteration is complex, and has not followed the text-book principles with a neat layer of supergene mineralization overlying fresh hypogene ore. Rather, the occurrence and extent of oxidation and supergene enrichment is highly irregular throughout the deposit, sometimes occurring at significant depth in localized pockets and along fault lines. Gold mineralization tends to follow the copper within the deposit, but it is dominated by coarse-grained, free-milling native gold. The extent of copper oxidation – measured as the fraction of total copper that assays as acid soluble – is used to classify ore into three main ore types, named Sulphide, Mixed, and Oxide, which are then fed to three different primary crushers for processing in independent circuits.

Jan 1, 2019

By Eugene McAuliffe

MANAGEMENT and control of any body of workmen can be effected through various - well-known methods &apos; though many managers hold certain personal theories of control that range from an absolute dictatorship to what might be called the principle of laissez faire, or the "let alone" method. Managements of many mines, factories, smelters and refineries have been compelled in recent years to accept certain restrictions in hours of labor as well as in methods employed, imposed either by federal or state laws, or by labor agreements. Broadly speaking, regulations of the above character were brought on the industry by managers who failed to recognize fully the rights of their employees to proper sanitary, safe, and compensatory working conditions, as well as working hours that were proper and just. As an example of poor management and worse psychology, we have only to hark back to the days when many bituminous coal operators maintained an inadequate number of pit cars for the number of miners or loaders employed, or if the pit cars were available, the haulage facilities

Jan 1, 1934

The Division of Minerals and Geochemistry in collaboration with three mineral exploration companies, Mawson Pacific Ltd, Ramsgate Resources Ltd and Tectonic Systems Pty Ltd commenced a two year research project to investigate the application of remote sensing techniques to exploration for mineral deposits in access of the Yilgarn Block in Western Australia. The project utilizes satellite data such as day and night imagery from the NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) satellite. The recent research with the imagery in the Kalgoorlie, Southern Cross and Mt Magnet regions has highlighted the advantages of the mid infra-red and the two thermal response channels of NOAA-AVHRR for geological investigations. These three channels have the spectral resolution to distinguish stratigraphic units and younger intrusive bodies, and to delineate fracture zones and shear zones associated with Proterozoic dykes. But most important is the capacity to distinguish thermal signatures from geological structure, near-surface outcrop and palaeochannels which have been covered by unconsolidated sediments. The research project applies remote sensing methods including enhanced satellite imagery optimised to the Western Australian environment. It encompasses data from both space and airborne monitoring platforms that have obsreved a significant spectral response for the classification of alteration zone lithologies. It includes the collection of multiseasonal data from areas of interest which is essential both for the understanding of thermal characteristics of important lithologies and for the extrapolation from field work investigation to potential exploration areas. No comprehensive investigation of this type has been carried out within the Yilgarn goldfields.

Jan 1, 1987

By R. J. Brison, R. D. MacDonald

This chapter is written primarily from the standpoint of development of flotation processes for treatment of specific ores. However, most of the principles and techniques discussed are equally applicable to other forms of applied flotation research such as improvement of procedures in existing plants and development of new reagents or methods without reference to specific ores. Because it is not possible to cover this subject in detail here, much of the material presented is in the form of a guide to the literature, with emphasis on readily available, English language publications. Details are included only if considered to be widely applicable or not readily accessible in the literature. Related subjects which are covered elsewhere in this volume, such as flowsheet design and statistical techniques, are not emphasized in this chapter. The material presented is intended primarily for those familiar with the theory and practice of flotation, but with limited experience in applied flotation research. It may be of value to the experienced investigator as well, by calling to his attention some useful viewpoints or techniques that he may have overlooked. It has often been said that flotation is more of an art than a science. In- deed much of the knowledge of flotation behavior is empirical. However, the unsystematic, artisan approach to flotation problems results only in an ac- cumulation of unrelated data. Like any other physical or chemical process, flotation is amenable to investigation by systematic experimental methods. The experiments should be based, as far as possible, on an understanding of the natural laws that govern the process and on good experimental procedures. SAMPLING OF A DEPOSIT In working out a flotation process for a mineral deposit, no step is more important than that of obtaining a suitable sample or samples. Experimental procedures cannot compensate for the lack of a representative sample. Methods of sampling a deposit have been published elsewhere,l-4 but a few points are of special importance from the standpoint of flotation. First, the sample should be representative of the deposit, not only in respect to chemical composition, but also in respect to mineralogical composition and degree of dissemination of the valuable minerals. To help ensure

Jan 1, 1962

By Henry F. Hebley

THE solid fuel industry, especially that branch represented by bituminous coal, is gradually becoming aware of its ? paramount importance in a world where there is an ever increasing demand for the products of a mechanical age. In practically every process of manufacture, the necessity for energy in some form is being multiplied. Some of that prime energy is derived from water power-hydro-electric schemes, flood control schemes, etc. - but often the electrical energy thus developed is generated at great distances from the load centres, requiring long transmission lines with consequent transformer and transmission losses. A few plants have harnessed the tidal power of the seas and one has harnessed the energy of the wind in a modern manner. All of these schemes are dependent on certain natural geographical, hydrographical, and physical advantages of terrain, as well as an adequate area of consumption of the energy developed. If flood control is the primary object, then power generation is a by-product; and the economics of large capital expenditure on power generating equipment must be considered in that light.

Jan 1, 1945

By Thiann R. Yu, William J. Quesnel

At Kidd Creek, the annual production of 4.5 million tonnes of ore has been achieved primarily with sublevel blasthole stoping. This mining method has allowed underground operations to meet the designed production capacity while maintaining an outstanding safety record. To achieve this goal, rock mechanics principles have been integrated into each facet of mining in the planning stage, in the production stage, and in various stages of ground support. This paper evaluates the two adopted mining sequences based on ground stress patterns, blasting control, ground reinforcement, backfill support, and numerical modelling for stope stability at the mines.

Jan 1, 1984

By Malcolm T. Wane

The subject matter of this paper, "Applied Rock Mechanics?," has its genesis in a recent field trip taken by the author. A more or less standard question asked at the mines visited was "How are you using the principles of Rock Mechanics to assist you in maintaining an efficient, safe, and competitive mining operation?" The question was couched in a number of different forms, but the intent was to determine whether or not a general theory based on reason and the scientific method was applied or whether the alternatives of tradition, intuition, ?common sense&apos;, revelation, ?shotgun methods&apos; or authoritarianism were invoked. Perhaps two responses to this query will be illustrative of the general nature of the replies. At operation XYZ an extension to the known ore body has been found. The extension is of large enough size and grade that a mining scheme using load-haul-damp techniques is envisaged. Since this represents a departure from the present mining scheme, questions have arisen regarding pillar sizes, room and entry sizes and possible support requirements. A task force has been set up to expeditiously plan for these things and write the necessary specifications and requirements. The fundamental question was posed to members of this group.

Jan 1, 1971

By Thomas J. Rudolphi

Efficient transport of bulk materials by belt conveyor systems is an important engineering design issue, especially as conveyors become longer and power requirements increase. It is well known within the industry that the parasitic energy loss of a belt conveyor, due to the indentation of the idlers into the belt backing material can be upwards of half the total energy required to drive it on a horizontal flight. Other loss sources includes the rolling resistance of the idlers, belt/roller misalignments, material trampling, frictional and acceleration losses on loading, etc., but energy absorbed by indentation of the belt backing as it passes over each successive idler is the dominant power consuming factor. INDENTATION LOSS MODELS Models to predict the rolling resistance of a cylinder (idler) on a viscoelastic foundation (backing material) have been available for some time. As a contact problem, it is nonlinear (contact length or indentation depth is a dependent on the load and vice versa) in load/deformation response. Rubber backing material is generally assumed to behave as a linear viscoelastic solid, even though it is known that most rubber compounds retain linearity only at very low strains. Because completely general solutions are impossible, practical solutions require simplifying assumptions. Those assumptions relate naturally to two separate pans of any analytical model: I. The deformation model-aspects of the problem relating to the geometry, boundary conditions and kinematics of how the material deforms. 2. The material model-aspects of the problem relating to the material properties, or constitutive relationships, i.e., the stress/strain relationships.

Jan 1, 2008