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By V. K. Paruchuri, J. D. Miller, J. Nalaskowski

The phenomenon of surfactant adsorption at mineral surfaces is of significant importance in many particulate processes ranging from mineral flotation and enhanced oil recovery to pharmaceutics, paint technology and the casting of high quality ceramics. Stability of the dispersions is related not only to the amount of adsorbed surfactant but also to the structure of the adsorbed surfactant molecules at the interface. This structure greatly depends on the type of surfactant and the hydrophobicity or hydrophilicity of the surface. On hydrophobic surfaces surfactants adsorb regardless of surface charge by van der Waals/hydrophobic inter-actions with hydrocarbon chains accommodated at the surface. On the other hand, on hydrophilic surfaces the surfactants adsorb through electrostatic interactions with their polar moiety fixed at the surface. In the latter case, the electric charge of the surface and surfactant plays a crucial role in the surfactant adsorption process. The recently developed soft-contact Atomic Force Microscopy technique has revealed images of adsorbed surfactant structures at various interfaces. The adsorbed structures of a cationic surfactant (CTAB) and an anionic surfactant (SDS) are presented in this work for different concentrations at hydrophobic graphite and hydrophilic mica surfaces. Different types of micellar arrangements have been observed at these surfaces for surfactant concentrations around the critical micelle concentration. The structures are more ordered and well defined at the graphite surface than at the mica surface. These results have been correlated with the hydrophobicity of the surfaces as revealed by contact angle measurements.

Jan 1, 2001

Syncrude Canada produces a large part of Canada’s crude oil supply. The company processes about 225,000 bbl/day. The oil produced is used for jet and automobile fuel, home heating oil, plastics and other consumer synthetics. Crude oil is produced through a process of mining, extracting and upgrading bitumen. A rich supply of bitumen is contained in the Athabasca oil sands deposit in northern Alberta. Tailings from the bitumen processing are sent to a settling basin.

Jan 1, 2000

By C. M. Rule

Energy efficiency is currently a significant area of interest due to the Eskom power situation, which led to severe power impacts to the PGM, and indeed whole SA primary industries, in early 2008. Anglo Platinum has focused on energy efficiency for a number of years, especially in the concentrator operational area. New comminution technologies have been aggressively developed, which have shown real metallurgical efficiency gains as well as significant energy efficiency and saving potential for Anglo Platinum?s total electrical consumption as the company expands into a growing PGM demand market. This paper illustrates this programme?s activities, potential and considerable achievements to date.

Jan 1, 2009

By Timothy M. Bruner, William J. Maloney

Faced with rapid growth that strained their current water supply capabilities, the Somerset Water Service in Somerset, KY decided to construct a new intake structure on the shore of Lake Cumberland. With an existing intake structure within 200', very hard limestone geology with calcite geodes, and lake level fluctuations as high as 50 ' ,this project posed many challenges. The following paper discusses how mechanical excavation techniques were used to overcome these obstacles.

Jan 1, 2001

By Harold J. Miller

Loading and haulage of run-of-mine ore is frequently the highest cost in underground mining operations. These costs can be significantly reduced by use of belt conveyors, a common practice in coal and similar soft miner ii mines. This is particularly true if oversize ore and rock can he eliminated prior to conveying; thus producing a demand for crushers near the production areas. Portable feeder-breakers are extensively used in conveyorized mines, but no suitable, equivalent equipment, is available to provide these benefits to hard rock mines of low to medium headroom. A hard rock crusher capable of easy movement and readily disassembled would allow use to belt conveyors and could improve the general safety and productivity of any underground ore hauling system. This report summarizes proposals and findings made in conjunction with the newly designed M-44 Low Head Portable Crusher which is believed well capable of meeting the requirements of a "portable, underground, hard rock" machine as previously defined in earlier reports. Data gathered by use of the 1/4 Scale Model of the M-44 has substantiated and verified the concept sufficiently to justify construction of a full-size machine for further testing under actual mine conditions.

Jan 1, 1978

By Dave Kay, Young-Suk Song

To meet the needs of South Korea's rapidly expanding economy, a large number of infrastructure projects are under way to improve transportation efficiency within the nation. These projects include high-speed rail links between major population centres and improvements to the road network. Being densely populated and geographically mountainous, infrastructure development in Korea requires a significant amount of tunnelling. Owing to the predominantly hard granitic nature of rock, drill and blast is the preferred method of tunnel advance. The Korean tunneller, however, faces the same pressures as those of his international counterpart in that both cost and production targets need to be achieved while meeting expectations of both community and regulator.

Jan 1, 2005

By S. Frimpong

Hydraulic shovels are widely used for primary production in surface mining operations. Variability in material diggability, unstructured mining environments and limited space and operator inefficiency affect the performance of these shovel excavators. Dynamic models of the hydraulic shovels are essential for understanding and improving machine performance. This paper contributes to this subject area by advancing hydraulic shovel kinematics and dynamics using the modified Newton-Euler method. A virtual simulator is developed to simulate the hydraulic shovel performance in the ADAMS environment. The simulator is validated with data on shovel geometry and the physical and mechanical properties of a formation in a surface mining environment. The results indicate that a shorter digging time increases the shovel operating power requirements, and that the required peak power increases by 100% when the digging time reduces by 50%. Simulation results also show that a shallow trajectory facilitates the digging process, with 50% reduction in peak power requirements compared to a deep one. This simulator provides a powerful tool for performance monitoring, excavation process designs and structural optimization of hydraulic excavators. This work also forms the basis for developing comprehensive simulator models for automated shovel operations in constrained mining environments.

Jan 1, 2005

By Tom Meikle

Long tendon support systems provide several challenges when used in-cycle as part of the secondary or primary support cycle. A two-component pumpable resin, Carbothix, has been in development for use with self-drilling rock bolts, but many of the attributes of this new resin system make it ideal for grouting long tendon support systems. While neat Portland cement grouts or polyester resin capsules have been used with long tendon support systems for many years, two-component pumpable resin systems overcome many of the shortcomings in these systems. The two-component systems dramatically improve the set-time to enable mining face advance with fewer delays, enable longer pumping distances, improve quality control, and enhance load transfer mechanisms. This paper describes the key benefits associated with a new pumpable resin and details the Australian Department of Mines and Petroleum department atmospheric testing results and cable load testing completed by Minova personnel to date. It also details the results of the Australian mine site trials and the introduction of these systems into production use.

Jan 1, 2012

By Robert C. Merritt

Laboratory amenability studies as well as a pilot heap-leaching investigation of low-grade sandstone uranium ores from Wyoming, New Mexico, and Colorado are described. Sulfuric acid heap leaching with oxidation, for 120 days, extracted up to 98 percent, 90 percent, and 79 percent U308 from Wyoming, New Mexico, and Colorado ores, respectively.

Jan 1, 1976

By James McKelvey, Larry Drolet, Jason Swartz

INTRODUCTION When divers discovered that sections of a tunnel housing the pipeline that conveys wastewater from the Charleston Peninsula to the Plum Island Wastewater Treatment Facility had caved in, the Charleston Commissioners of Public Works(CPW) moved quickly to determine a long term solution for the city’s collection system, immediately focusing on the Ashley River sewer tunnel along the western boundary of the peninsula. Working with the Charleston community, as well as federal, state, and local officials, CPW developed a fast track yet long life design that can be used as a model for underground construction of tunnels in urban areas. The paper that follows summarizes key aspects of the Ashley River sewer tunnel project. HISTORICAL CHARLESTON Charleston, South Carolina is a culturally significant and historic city that was originally settled in 1670. There are over 100 buildings on the National Register of Historic Places within the Charleston area. Additionally, the first shots of the American Civil War were fired at Fort Sumter in the Charleston Harbor in 1861. As one can imagine, tourism generates significant business for the area with over 1.5 million people visiting Charleston each year. No project, especially one that requires digging, is done within the old city on the Charleston peninsula without careful planning. Many precautions are necessary to prevent damage or disruption to the historical properties. The Ashley River sewer tunnel project is exclusively in the old city. A lot of work was done during the design phase to minimize the impact to historical properties. Some of this work included: an archeological study (where pre-digs were monitored at all shaft sites by an archeologist); a building/structure assessment study (where structures near a shaft site were completely surveyed and cataloged); and an environmental study.

Jan 1, 2005

By G. J. Hasenfus

This paper presents the results of an extensive hydrological and geomechanical monitoring program which Gas conducted at a longwall coal mine in W. Va. The field program included monitoring of groundwater levels. overburden hydraulic conductivity, overburden movement, and surface subsidence relative to the passage of the longwall. Overburden geology and rock strength characteristics were evaluated prior to mining. A postmining corehole was drilled to evaluate main roof fracturing. An overburden response model is proposed based on the correlations between hydrological and geomechanical data.

Jan 1, 1988

By W. Robert, J. Wirth, G. Grasselli

ABSTRACT: Strength, deformability and fluid flow properties of rock joints are to a great extent controlled by the surface roughness. The hydraulic conductivity of a rock fracture depends on the aperture distribution, the surface roughness and the contact area, each of which depend on the stresses that act on the fracture plane. However, despite much recent work, a complete understanding of the relationship between void space geometry, contact areas, applied stress, and hydraulic conductivity has yet to be achieved. Moreover, although in situ rock joints are subjected to both normal and shear loading, few studies have been conducted to investigate the effect of shear displacements on fluid flow through a single rock fracture, and which have addressed the issue of flow anisotropy induced by shearing. Experimental flow tests show that with increasing shear displacement, the fracture becomes heterogeneous and anisotropic, and becomes more permeable in the direction parallel to the displacement (Yeo et al., 1998). On the other hand, dry shear tests show that the surface fails in areas facing the shear direction (Grasselli and Egger, 2003). Moreover, the experimental results confirm that the shear strength of rock joints is direction-dependent. In this paper, a three-dimensional morphological description of several a natural fractures that have undergone shear displacement were generated using the Automated Topographic System at the University of Basel. The data analysis method of Grasselli (Grasselli et al., 2002a) is used to determine the surface parameters that are known to control the shear strength. Simulations of fluid flow through this fracture, in various directions relative to the direction of shear, are conducted using an FEM flow simulator. The results constitute the most detailed analysis yet undertaken of the relationship between shear displacement, shear strength, and fracture transmissivity. RESUME: La rugosité des joints en roche joue un rôle primaire sur la réponse hydromécanique du massif fracturé. En effet, la conductivité hydraulique des discontinuités en roche est influencée par la rugosité, et par la distribution des ouvertures et des zones de contact, dont chacun dépend de l’effort normal et du cisaillement qui agissent sur la surface du joint. Les essais d'écoulement en laboratoire montrent que si cisaillée, la fracture devient anisotrope, et plus perméable dans la direction parallèle au déplacement (Yeo et al., 1998). D'autre part, les essais de cisaillement indiquent que seules les zones de la surface qui font face à la direction de cisaillement sont impliquées dans le cisaillement (Grasselli et Egger, 2003). D'ailleurs, les résultats expérimentaux confirment que la résistance au cisaillement des joints de roche est dépendante de la direction. Dans cet article, plusieurs fractures en roche ont été analysées en utilisant un système de mesure topographique à l'Université de Bâle. La méthode d'analyse de données proposée par Grasselli (Grasselli et al., 2002a) a été employée pour calculer les paramètres de la surface qui déterminent la résistance au cisaillement. Plusieurs simulations du coulage, dans diverses directions relativement à la direction du cisaillement, ont été faites à l’aide d’un programme de calcul à éléments finis. Les résultats constituent une des analyses les plus détaillé sur le rapport entre le déplacement pendant le cisaillement, la résistance au cisaillement, et la transmissivité spécifique de la fracture. ZUSAMMENFASSUMG: Die Festigkeit, Verformbarkeit und Hydromechanik von geklüftetem Fels wird hauptsächlich von der Oberflächenrauhigkeit der Bruchflächen bestimmt. Die hydraulische Leitfähigkeit einer Kluft hängt von der Verteilung der Rissbreiten, der Oberflächenrauhigkeit und den Kontaktflächen ab, die ihrerseits von dem auf die Bruchfläche wirkenden Druck beeinflusst werden. Obgleich in letzter Zeit viel in dieser Richtung geforscht wurde, kann der Zusammenhang zwischen Porenraumgeometrie, Kontaktflächen, wirkendem Druck und hydraulischer Leitfähigkeit noch nicht vollständig erklärt werden. Obwohl Klüfte in situ sowohl Normal- als auch Schubspannungen ausgesetzt sind, wurde der Einfluss von Scherverschiebungen auf den Kluftwasserfluss und die daraus resultierende Fliessanisotropie in einer einzelnen Kluft bisher kaum untersucht. Experimentelle Untersuchungen des Durchflusses zeigen, dass die Kluft für größer werdende Scherverschiebungen heterogen und anisotrop wird wobei die Permeabilität parallel zur Verschiebungsrichtung ansteigt (Yeo et al., 1998). Andererseits zeigen trockene Scherversuche, dass die Oberfläche an Stellen versagt, die gegen die Verschiebungsrichtung anstehen (Grasselli und Egger, 2003). Des weiteren bestätigen die experimentellen Ergebnisse eine Richtungsabhängigkeit der Kluftscherfestigkeit. In diesem Artikel wird eine dreidimensionale morphologische Beschreibung mehrerer natürlicher, durch Scherspannungen verschobener Klüfte vorgestellt, die vom Automated Topographic System der Universität von Basel erstellt wurde. Das von Grasselli (Grasselli et al., 2002a) entwickelte Datenanalyseverfahren wird zur Feststellung der die Scherfestigkeit bestimmenden Oberflächenparameter herangezogen. Mittels einer FEM-Simulation wird der Durchfluss durch eine solche Kluft in verschiedenen Richtungen simuliert. Die Ergebnisse stellen die bisher ausführlichste Analyse des Zusammenhangs zwischen Scherverschiebung, Scherfestigkeit und Durchlässigkeit (Transmissivität) einer Kluft dar.

Jan 1, 2003

By Daniel Hauer

Blocking. (5) The “blocking” of boulders is a much cheaper way of breaking them up than “mud capping.” It should always be used in preference to that method except when too much time will be consumed by a crew of men waiting for the drilling to be done, as shown in example of cost No. 1, as given under “mud capping.” Under such circumstances the time consumed would be a greater cost to the contractor than the extra amount of dynamite. Then, too, on large thin boulders to drill one hole would result only in breaking the stone into such pieces as would again have to be broken; and the many holes might equal the cost of extra dynamite. Under such circumstances if method (6) cannot be used, “mud capping” will have to be resorted to, to do the work economically.

Jan 1, 2006

By J. A. Cox

The Ashanti mine is located within the Lower Proterozoic Birimian of Ghana, and covers a concession of 474 square kilometres at its Obuasi operations which comprise large scale underground, surface and tailings treatment facilities. The mine had operated for a century at the end of 1997 and had produced nearly 25 million ounces of gold, a significant proportion of which came from the underground operations. This paper covers the strategy under which exploration for both surface and underground mineral resources was instrumental in enabling the expansion programme to go ahead together with the methodologies and results that have developed in the exploration area over the last five years. Within capital expenditure constraints, the objective on surface is to replace oxide depletion with a secondary objective of discovering new sulphides in areas other than the main trend. In the underground, the exploration strategy is directed at replacement of both underground and surface sulphide depletion, minimising finding costs and assisting the development of long lead time infrastructure. The exploration application describes the methodologies in use for both surface and underground exploration that have been developed in recent years in conjunction with a description of a major review conducted in 1995/96 of the exploration database using an integrated approach, geochemistry, geophysics, remote sensing and structural geology. A revisit of soil geochemical data in particular, and modification of exploration methodology led to the success in finding relatively significant new oxides in 1997.

Jan 1, 1999

By D. F. Malan

This paper provides an overview of the concepts of citations and journal impact factors, and the implications of these metrics for the Journal of the Southern African Institute of Mining and Metallurgy (JSAIMM). Two key research literature databases publish journal impact factors; namely, Web of Science and Scopus. Different equations are used to calculate journal impact factors and care should be exercised when comparing different journals. The JSAIMM has a low impact factor compared with some of the more prestigious journals. It nevertheless compares well with journals serving other mining sectors, such as the Canadian CIM Journal. The problems associated with journal impact factors are discussed. These include questionable editorial practices, the negative impact of this concept on good research, and the problem of a few highly cited papers distorting the journal impact factor. As a consequence, there is growing resistance to the use of journal impact factors to measure research excellence. The San Francisco Declaration on Research Assessment is a global movement striving for an alternative assessment of research quality. As a recommendation, the Editorial Board of the JSAIMM should adopt a pragmatic approach and not alter good journal policies simply to increase the journal impact factor. The focus should remain on publishing excellent quality papers. Marketing of the Journal, the quality of the published papers, and its open access policy should be used to counter the perception that journals with high impact factors are better options in which to publish good research material.

Sep 1, 2022

By P. L. Crouse, S. J. Lubbe, M. J. Kabangu

A selective extraction and separation of zirconium by solvent extraction with 1-octanol is proposed. The process is based on the dissolution of the metal basic carbonates in hydrochloric acid in the presence of potassium fluoride, using 1-octanol as extractant. The effect of several process parameters, including hydrochloric acid and potassium fluoride concentrations, reaction time, and phase ratio between the aqueous and the organic phase was investigated. Zirconium is enriched in the organic phase. The best extraction and separation results were obtained with the basic carbonate dissolved in 10% hydrochloric acid and 1.5 M potassium fluoride. The optimum reaction time was 15 min with an organic to aqueous phase ratio of 2:1. Based on the selectivity of zirconium over hafnium in the organic phase, a McCabe-Thiele diagram was constructed. A near complete stripping of zirconium from the organic phase was achieved using a 3 M sulphuric acid solution. Additional studies are required in order to determine the reaction mechanism and the chemical speciation of the current investigation.

Pillars in underground limestone mines are required to support the overburden and provide a safe, stable working environment for mining personnel and equipment. Pillar stability was assessed by the National Institute for Occupational Safety and Health in underground limestone mines in the Eastern and Midwestern United States. It was found that current mine layouts have been successful in providing support to the overburden, while a small number of isolated pillar failures were observed. The stable pillar layouts and failed pillars were plotted on a chart that demonstrates the relationship between pillar width-to-height ratio and pillar stress. The results show that pillar failures occurred at the lower range of width-to-height ratios and can occur at relatively low stress levels. Zones indicating the potential risk of pillar instability are shown on the chart, based on hazards associated with the onset of rib spalling, large angular discontinuities and unconfined pillars. The chart can assist limestone mine planners to evaluate potential instability in current or new pillar layouts that are similar to those included on the stability chart.

Jan 1, 2008

By S. Dessureault

Computer Integrated Mining (CIMG) is a process of using computer networks to transform islands of enabling technologies into a highly interconnected mining system. CIMG involves the integration of advanced technologies at various levels in the mine business to achieve higher flexibility, better quality of processes and control, and improved profitability. Justifying the benefits of CIMG are difficult as many of the advantages are derived from improved flexibility, quality, and control. Justification is based on the evaluation of the benefits to be gained, compared to the required capital investment. Management tools used in mining are currently inadequate in assessing the value of advanced technology whose benefits are primarily qualitative. A key aspect of successful implementation is management acceptance, which has to be won through the capability to justify the technology?s financial costs and the true value of all of its benefits. The manufacturing industry faced similar justification difficulties when adopting advanced technology in factories. A significant amount of funding and research was invested in developing management strategies and approaches to justification. Many of the problems that faced the transformation of the manufacturing industry in the late Eighties and early Nineties are now facing mining. The solutions derived for manufacturing may help mining in its transition to an increased reliance on integration technology. Reviewing the industrial history of computer integrated manufacturing identifies several tools and strategic frameworks that can be adapted for mining. Keywords: Computer integrated mining, justification techniques, CIM, information technology.

Jan 1, 2004

By B. Lueger, D. Shen, M. Sedighy, R. Rand, R. Saleh, J. Cheung, M. Rifai, I. Khan, W. Sauri, D. Setianto

The world’s first active power demand stabilization system for a 3-electrode electric arc smelting furnace was commissioned at PT Vale Indonesia in December 2012 on Furnace No. 2 using an SPLC (Smart Predictive Line Controller). The SPLC technology in combination with the Furnace No. 2 rebuild and other upgrades has enabled PT Vale to increase the electrical input to the furnace by up to 20% on a stable and sustainable basis by eliminating peak powers that overload and trip out the electrical equipment, and by reducing power unbalances. The SPLC technology maintains smooth arc power using a continuously variable thyristor controlled series reactor. The SPLC compensates variations in the furnace arc with predictive changes in the circuit reactance at a speed of up to 60 times a second. The system started up quickly and has been shown to be easy to operate and maintain by PT Vale. PT Vale’s Operations Team has been testing the new system at set points of up to 90 MW on the newly re-built Furnace No. 2. Over the last 12 months, the throughput of Line 2 has increased by approximately 10% on an annual average; however, debottlenecking in other design areas of the operation is required in order to achieve 90MW operation on a sustainable basis. This outstanding success results from a combination of the furnace and other upgrades, the SPLC active power stabilization, and the skill of PT Vale in quickly adopting new technologies and maximizing the combined benefits of each technology in their operation.

Jan 1, 2014

By James W. Stewart, A. C. Colvine

Introduction Precambrian shield terrains the world over are experiencing an unprecedented level of concerted exploration for lode gold deposits. Reasons for this include: • The increase in the price of gold (following 40 years at $1.13/g or $35 per oz) has transformed targets that were once unattractive into viable exploration propositions. • The relatively suppressed market for other metals produced from shields (base metals, nickel, iron, and uranium) has further focused exploration attention on gold. • The preeminence of gold production from rocks of early Precambrian age, as shown in Fig. 1. • The relatively high grade of gold in these mines (averaging about 10 Wt or 0.29 oz per st) permits profitable extraction even under depressed gold prices. A number of these mines have been in continuous operation for more than 50 years. • The recent discovery of the major Hemlo deposit, in well exposed rocks adjacent to the Trans Canada Highway, has had a world-wide impact. This demonstrates that a major new deposit can be found even in an accessible, well exposed area of a shield; gold mineralization is susceptible to rational exploration; and new target types for gold exploration exist. This paper reviews exploration activity for gold in shield terrains worldwide (Fig. 2), excluding Early Proterozoic paleoplacers of the Witwatersrand type. Emphasis is on the Archean, which is traditionally the most productive part of the Precambrian shields. There is also an emphasis on the Canadian shield (Fig. 3) because of its vast areal extent and exceptionally broad range of mineralization styles. Geological Approach A basic problem exists in gold exploration when compared to exploration for base metal massive sulfides that predominated during the 1960s and 1970s. Gold concentrations cannot usually be detected by airborne geophysical instruments. The majority of massive sulfide deposits were detected using airborne electromagnetic detectors and magnetometers. A full 75% of Canadian gold discoveries can be credited to surface prospecting. The percentage is even higher in other countries. This observation allows for great optimism for two reasons: • Large areas of shield terrain are obscured by either surficial deposits (glacial tills, clays, and desert sands) or deep surface weathering. This makes them inaccessible to prospectors. Logic dictates that such obscured areas should have the same potential for gold concentration as has exposed bedrock. • The Hemlo style of mineralization, a roughly tabular ore body where gold is associated with disseminated sulfides, is different from the traditional prospecting target. The gold is hosted by discrete quartz veins. While it is true that limited discoveries were made at Hemlo more than 30 years ago, and this style of mineralization is present elsewhere, recent

Jan 12, 1984