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By M Wilson, D Whiteman, P Kuiper, S Talu, G Watt, A van As

Once the draw process has begun in a block cave, it is very difficult to identify which regions of the cave have successfully propagated, where the caved material is flowing from and where it is flowing to. The uncertainty around cave flow increases as the cave is drawn and can be further compounded by poor draw control practices. These uncertainties make it difficult to plan effective draw strategies to control dilution, as flow model predictions tend to gradually diverge from the actual state of the cave. There have been documented occasions where observed caving phenomena, such as muck pile surface rilling, could not be reproduced with the cave flow models of the time. The ultimate consequence of cave flow uncertainty is generally manifest as higher dilution and lower grades.In order to measure the real-time flow of caved material within an active block cave, CRC Mining and Elexon have developed, together with Rio Tinto, a cave flow monitoring system called Cave Tracker, which is being trialled at Argyle Diamond Mine (ADM) in Western Australia. The Cave Tracker system at ADM comprises electronic ‘beacons’ that have been installed down long HQ diameter drill holes located above the extraction level. As the cave-back propagates and the rock mass fragments, beacons are released into the muck pile and flow along with the caved material to the drawpoints below. At Argyle, the beacons are configured to emit a signal every three days. These signals are picked up by detectors installed on the extraction and undercut levels, allowing the positions of the beacons to be determined.By examining the real-time material flow in different regions of the cave, flow mechanisms can be better defined. Draw control strategies can then be actively tailored to manage the current state of the cave. Thus, previously undetectable indications of excessive rilling, rapid cave propagation, cave stall, air gaps and dilution entry can now be identified early and assessed continuously as the cave progresses. For the first time it is possible to amend draw strategies based on measurements from inside and outside of the fractured zones, allowing caves to be managed more effectively.CITATION:Whiteman, D, Talu, S, Wilson, M, Watt, G, Van As, A and Kuiper, P, 2016. Cave Tracker flow monitoring system installation at Argyle Diamond Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 479–488 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D. deV. van der Spuy

A procedure for optimizing the secondary cooling zone of continuous casters is proposed and illustrated by a billet caster example. The procedure consists of quantifying deviations from the required conditions of the secondary cooling zone?as far as temperatures, metallurgical length and reheating are concerned?by means of a ?cost function?. The optimal spray settings are then found by minimizing the total ?cost?. The billet caster examples serve to emphasize the importance of specifying the required conditions in a consistent manner. Some envisaged practical limitations of this approach are discussed.

Jan 1, 1999

? Founded In 1953 ? Mining growth of 83% since 2007 ? We produced over 1 million ounces of Au in 2012 ? We Forecast of 20% Au production in 2013-2015 ? We have paid a dividend 31 years consecutively. Terry Reid ? 1992-93 Electrical Technical, College ? 1994-95 On the job placement College ? 1998 ? Licensed Millwright, ? 2005-12 ? Maintenance Reliability Planner ? 2012- Present Business Process Owner

Aug 1, 2013

By R. S. Dean

[During the past fiscal year the Metallurgical Division has made important contributions along the lines dictated by the Bureau policy of conservation of domestic mineral resources through Its investigations include determining of fundamental data of metallurgically important materials improvement of standard ore-treatment method to eliminate waste and improve the grade or recovery of the products; and development o new metallurgical processes.]

Jan 1, 1940

A comprehensive axial test program has been undertaken at the WASM Dynamic Test Facility on the performance of 20mm threadbar. The threadbar tests had a double embedment configuration, with variation to the encapsulation lengths, debonded length and surface hardware and fixtures to examine failure mechanisms. Performance was significantly affected by the collar embedment length and type of fixture nut used. Results ranged from thread shearing occurring between the nut and bar at 1kJ of energy dissipated, to control plastic deformation of a central debonded length dissipating 22kJ.

May 1, 2009

By William Escudero

El presente trabajo describe el planeamiento estratégico para el sostenimiento de la sociedad minera El Brocal a través de la gestión en el trabajo organizacional. Su principal objetivo es aumentar la productividad y la reducción de costos de minado y la planta concentradora. Para ello, se tomó el modelo de planeamiento estratégico desarrollado por Fred David y se realiza el análisis y diagnóstico interno de la empresa, a partir de los antecedentes, situación actual de la empresa, evaluación de la misión, objetivos actuales y cadena de valor de la empresa, luego se clasifica a la industria minera y se integra los resultados obtenidos, la matriz de evaluación del factor externo (EFE) y la matriz de evaluación del factor interno (EFI); para así elaborar la matriz (FODA) a partir de la cual se formula as estrategias por seguir. Finalmente, se redefine la misión de futura de SMEB y se ejecuta las estrategias y las acciones en las áreas funcionales.

Sep 13, 2001

By A van Jaarsveld

Environmentally-friendly, safe and cost-effective technology for stope drilling has successfully been introduced at TauTona mine. It has enabled the problem of inadequate compressed air pressure and its downgrading impact on production capability to be overcome. The paper traces the development process which culminated in the conversion of the entire stoping operation at TauTona to electric drilling. Background work which took place at other mines is also described. Statistics of performance improvements are provided. 1. Introduction Holman?s Silver series and the Seco S215 were drills that had a measurable impact on the South African gold mining industry. It is too soon to say whether Hilti will join those great names. However, there is no doubt that the introduction of electric drills into the harsh and unforgiving world of deep level gold mining is a significant development. History has shown that being the first to enter a new technology is no guarantee of long-term success. The pain and suffering which accompany the birth of anything new can deplete the energy of the innovator while at the same time creating opportunities for competitors to leapfrog him. In addition to commitment and enthusiasm, the innovator must therefore also possess, or have access to stamina and resourcefulness to overcome the unexpected difficulties which will inevitably arise. All of these were needed for the Hilti project.

Jan 1, 2008

By H. M. Lizama, R. L. Stephens

Secondary leaching of previously leached supergene copper ore has been developed and implemented at Teck’s Quebrada Blanca operations. This consists of using in-situ leaching techniques aided by geophysics to recover the residual metal value from dormant copper leaching heaps. These heaps of crushed and agglomerated ore had been leached 20 years previously but still contained significant copper values. The concept was first tested on a 3,200 m² sector, where injection wells introduced leaching solution into a production zone and electro-resistivity tomography was used to track solution movement within. Operating parameters such as well spacing and injection flow rates were determined. Copper recovery and leaching performance were evaluated based on solution and metallurgical balances. Both ferric leaching and bacterial leaching were enhanced through strategies to pull air into the heap. Positive results from the initial test prompted a larger, industrial pilot test on a 60,000 m² area and 97 injection wells. This larger test obtained a copper recovery of 30% in 457 days. Secondary recovery is now being implemented to all of the abandoned heaps at Quebrada Blanca and has become a production stream. This technology has the potential of wide application to mature copper heap leach operations, and Teck has patented the process and associated methodologies. INTRODUCTION Heap leaching of copper secondary sulphides has been carried out at Quebrada Blanca (QB) since 1994. Ore from the supergene deposit was crushed and agglomerated prior to leaching. Originally, the ore was leached in 6 m lifts stacked one on top of another, known as a static pad configuration. However, in 1998, after the second lift, the operation changed to a dynamic pad configuration; the ore was leached in a single lift and the resulting residues were removed to make way for fresh ore (Yáñez, Ahlborn, & Ramos, 2007). The first two static lifts were left in place and served as a foundation for the dynamic lifts above. Those two buried lifts of leached residues, some 16.8 million tonnes and covering an area of approximately 0.71 million m², remained buried under the dynamic pad.

Jan 1, 2019

By J. M. Jimenez, G. D. Schena, A. J. Cazorla

A full-scale Deister column was operated in parallel with the conventional cleaning bank of cells and a pilot Jameson cell in parallel with the conventional rougher cells. Flotation column performance was appreciably enhanced by use of an improved washing system and an internal launder. The performance of the rougher bank of cells, Jameson cells, cleaner cell bank and column were described by simple linear functions. These allowed calculation of overall circuit recoveries and evaluation of alternative circuits. An evaluation procedure based on a financial criterion is demonstrated with a simplified example, illustrating how revenues and operating margins are often of more concern than concentrate grade and recovery

Jun 18, 1905

By Chu E. Ho

Current methods of determining jet grout column diameters are highly empirical and site specific, and do not take into account the jet hydrodynamics and soil parameters explicitly. A theoretical model which describes the jet excavation mechanism is introduced in this paper, with the aim of providing an improved prediction tool that can be used in jetting design. The model is based on the assumption that the velocity distribution in the cutting jet is equivalent to that of a free jet with boundaries corresponding to the dimensions of the cavity excavated in the ground. The shape of the cavity formed depends on the erosional properties of the soil and jet expansion is limited by the resistance at the jet-soil interface. The model predicts that the limit of jet penetration is reached when the average dynamic pressure at the jet tip becomes equal to the ultimate soil bearing resistance. The reliability of the model, evaluated using results from four case histories of jet grouting field trials, is within ±15%.

Jan 1, 2006

By Patrick J. Williams, Peter J. Pollard

"Abstract - Enigmatic hydrothermal vein/breccia/replacement Cu-Au deposits with magnetite and/or hematite are well-represented in Australian 1850 Ma to 1500 Ma terrains and associated with different-aged synorogenic intrusions in the Tennant Creek Block (ca. 1850 Ma); the Gawler-Curnamona region (1640 Ma to 1590 Ma); and the Cloncurry district (Mount Isa Eastern Fold Belt, 1540 Ma to 1500 Ma with a possible earlier event at ca. 1600 Ma). No deposits are known to be coeval with various 1780 Ma to 1610 Ma anorogenic intrusions. Deposits are hosted by many different rock-types with varying metamorphic grade including granites and various supracrustal rocks. Depth of mineralization varied from many kilometers in semiductile crust (e.g., Cloncurry deposits) to very shallow (e.g., Olympic Dam). Ore deposition near Cloncurry occurred in brittle-ductile shear zones from geochemically variable and complex, CO2-rich, 300°C to 500°C, high salinity fluids with magmatic stable isotopic signatures. Recently published studies of a giant granitoid-hosted magnetite vein complex at the Lightning Creek prospect (>1000 Mt magnetite) suggest it is a product of internal differentiation and endogenous Fe and Cu-rich hydrous-carbonic fluid phase generation within a quartz monzodiorite-monzogranite intrusion. Coupled with other field relationships, this points to a possible genetic relationship with intermediate (55 to 65 wt% SiO2) members of an alkaline and partly shoshonitic granitoid supersuite which appears to have both mantle and crustal source components from ?Nd evidence. In constrast, main-phase mineralization at Olympic Dam in the Gawler Craton is distinguished by hematite-phyllosilicate alteration and chalcopyrite-bornite-chalcocite zoning, reflecting fluid mixing in a high level (<250°C) system with a probable large component of meteoric water. Early high-temperature parageneses and fluid inclusions imply that the extensive hematitic breccias overprinted an older magnetite system which may have had similarities with those at Lightning Creek and Ernest Henry in the Cloncurry district.Deposits of this family are inherently difficult to find and evaluate as even within a single district, there is no reliable relationship between the location of ore and any specific combination of geophysical characteristics. Diverse alteration assemblages, geochemistry and physical characteristics suggest the deposits reflect the interaction of multi-sourced fluids with different host rocks in a wide range of geological environments. Recent discoveries and research in the Cloncurry district have extended the range of deposit models available and aid the development of a rudimentary classification in which economic and exploration characteristics can be linked to variations in the mechanisms and environments of ore formation."

Jan 1, 2001

By T. Kagogo, M. Neser, C. Knobbs, E. Gerryts

"Contrary to the way it is often portrayed, the average organization or company is far from being a cold, calculating machine. It is actually a highly emotive place where interaction with people is a fundamental part of its ability to perform satisfactorily.The company, through its employers, expects employees, including new graduates, to have the ability to cope adequately with this emotive environment. The graduate is frequently unable to meet this expectation because he/she has not been developed to do so. Technical knowledge is his only asset. This deficiency manifests itself in leadership shortcomings, both intrapersonal and interpersonal. Further analysis reveals a deficiency in three elements of leadership - self-awareness, oral communication, and an ability to work cooperatively in teams.To address these three elements of leadership, Sasol Coal, a subsidiary of the big petrochemical company in South Africa, sponsored a leadership programme at the University of Pretoria for their final-year bursary students in the faculty of Engineering. This programme, the Sasol Engineering and Leadership Academy (SELA), consisted of a number of interventions designed to address the three areas of self-awareness, oral communication, and cooperative behaviour in teams. These interventions varied from an intrapersonal nature to interpersonal aspects. Psychometric assessments were followed by experiential modules dealing with the three constructs.SELA was evaluated at the end of the year. The results showed a positive shift in the main constructs of self-awareness, communications, and cooperation. This was measured quantitatively and qualitatively. Conclusions were drawn and recommendations for improving the programme were proposed."

Jan 1, 2014

By C. Knobbs

Contrary to the way it is often portrayed, the average organization or company is far from being a cold, calculating machine. It is actually a highly emotive place where interaction with people is a fundamental part of its ability to perform satisfactorily. The company, through its employers, expects employees, including new graduates, to have the ability to cope adequately with this emotive environment. The graduate is frequently unable to meet this expectation because he/she has not been developed to do so. Technical knowledge is his only asset. This deficiency manifests itself in leadership shortcomings, both intrapersonal and interpersonal. Further analysis reveals a deficiency in three elements of leadership ? self-awareness, oral communication, and an ability to work cooperatively in teams. To address these three elements of leadership, Sasol Coal, a subsidiary of the big petrochemical company in South Africa, sponsored a leadership programme at the University of Pretoria for their final-year bursary students in the faculty of Engineering. This programme, the Sasol Engineering and Leadership Academy (SELA), consisted of a number of interventions designed to address the three areas of self-awareness, oral communication, and cooperative behaviour in teams. These interventions varied from an intrapersonal nature to interpersonal aspects. Psychometric assessments were followed by experiential modules dealing with the three constructs. SELA was evaluated at the end of the year. The results showed a positive shift in the main constructs of self-awareness, communications, and cooperation. This was measured quantitatively and qualitatively. Conclusions were drawn and recommendations for improving the programme were proposed.

Jan 1, 2014

By T. Nishimura, H. Kiyama, K. Wakimoto

Discussion on the load bearing capacity of ground and the stability of tunnel is presented. We derive a simplified solution of a circular lined-tunnel in an elastic ground. The solution results in a better understanding of characteristic curves. Use of DEM allows us to consider effects of possible yield of the overstressed zone around the tunnel and inherent discontinuity of ground on the curves. Diskussion auf der Last Tragfähigkeit Bodens und die Stabilität des Tunnels wird dargestellt. Wir leiten eine vereinfachte Lösung eines kreisförmigen Ausbautunnels in einem elastischen Boden ab. Die Lösung ergibt ein besseres Verständnis der Kennlinien. Um Gebrauch DEM erlaubt uns, zu betrachten Effekte des möglichen Ergebnisses der überbetonten Zone den Tunnel und zugehörige Unstimmigkeit des Bodens auf den Kurven. La discussion sur la portance de charge de la terre et de la stabilité du tunnel est présentée. Nous dérivons une solution simplifiée d&apos;un revêtement-tunnel circulaire dans une terre élastique. La solution a comme conséquence une meilleure compréhension des courbes caractéristiques. L&apos;utilisation de DEM nous permet de considérer des effets du rendement possible de la zone surchargée autour du tunnel et de la discontinuité inhérente de la terre sur les courbes.

Jan 1, 2003

By John B. Sabey, Vernon R. Degner

The industrial coal processing trend toward greater fines production, due to mining techniques and customer requirements for reduced ash and sulphur content in the fine coal product, is the basis for ongoing efforts to improve the performance of the flotation machine. WCO has successfully adapted the principles of the beds Column to a full size machine prototype. Recent plant evaluation tests confirmed the initial promise of this concept by achieving a considerably lower ash product while maintaining the combustible recovery level of conventional flotation machinery. The paper will include a review of the fundamental principles of the beds Column concept, together with a summary of the WEMCO R&D Program from concept evaluation and laboratory testing, through pilot, to full size machine tests. The performance of the WEMCO/Leeds flotation column will be compared to conventional flotation concepts using a flotation "kinetics" approach, which quantifies the floatable and non-floatable specie recovery performance using the Klimpel model as the basis for analysis. The variety of distinct features unique to this concept include a series of barrier rods which are used to advantage, often together with countercurrent reflux water flow, to achieve a significant improvement in product grade. The hydrodynamics associated with the mechanics of "gangue stripping" from the rising "air bubble-floatable specie" matrix will be briefly reviewed.

Jan 1, 1988

The achievement of high availability of the Grey River Gold Mining Limited&apos;s alluvial gold dredge is a tortuous task which will rely upon the dedication of all staff employed at Grey River Gold Mining Limited (GRGML). The persistent adoption of new technology and better operating procedures, combined with a strong commitment to preventative and predictive maintenance, is necessary. The Grey River Gold Mining Limited alluvial gold dredge is operating in a relatively low grade alluvial gold deposit and hence relies on a high throughput of ore to be profitable. To achieve the required high material throughput the dredge incorporates an overburden removal system which operates simultaneously with a conventional bucketline system. &nbsp; The overburden system incorporates a cutter wheel and suction pump configuration which is dedicated to removing the low grade (5 mg gold/m3 gravel) overburden. The bucketline conveys the richer grade payzone gravels (up to 890 mg/m3 gravel) to the recovery plant mounted onboard the dredge. The horizon for the overburden system approximates 15 m and the payzone terminates at the interface of the old man rock and the alluvial gravels at a variable depth averaging 22 m. &nbsp; From a mechanical engineering perspective the dredge is a machine comprised of two materials handling systems which are controlled by Operations Staff and electronic process control systems. &nbsp; The availability of such a materials handling system is a function of four variables: 1. The environment that the machine operates in. 2. The ability of the people operating the machine. 3. The design of the mechanisms, the configuration that they are grouped in and the effectiveness of the process control systems which control the mechanisms. 4. The procedures utilised to predict the performance of the machines and the skill of staff to analyse that data and carry out effective maintenance.

Jan 1, 1989

By G. van den Berg

Anglo Platinum has initiated a project to investigate hydraulic hoisting technology for platinum mines. Hydraulic hoisting systems are categorized as pumping, fluidizing feeder or displacement feeder systems. Positive displacement piston diaphragm pumps are most suitable for pumping systems but they require that the ore be milled prior to pumping. Fluidizing feeders are unsuitable for platinum ore applications due to the large percentage of fines in the ore. The three-chamber pipe displacement feeder has been most widely used for hydraulic hoisting and is the most suitable technology for platinum mines. Eight hydraulic hoisting applications covering pumping and displacement feeder technologies are reviewed. The key factors to be assessed in selecting a hydraulic hoisting system for a platinum mine are discussed. A typical platinum mine configuration will comprise an ore preparation plant (to produce -15mm material through screening or crushing), motive water pump on surface, high pressure water pipeline from surface to underground, ore slurrification plant, three-chamber displacement feeder, and a high pressure slurry pipeline to surface. The water and slurry pipelines are housed in a purpose drilled borehole. A hydraulic hoisting system selection chart is presented. A 150mm diameter system with a 25 MPa pressure rating is required to hoist 60 000 t/m from a depth of 1 200 m. Generic capital and operating costs are presented. A major potential advantage of hydraulic hoisting is that the fines, which contain a high percentage of PGMs, are captured underground and transported directly to the concentrator. Hydraulic hoisting technology is ideally suited to providing supplementary hoisting capacity to existing shafts that have reached the skip hoisting capacity limit. The main advantage for new shafts is the potential to significantly simplify underground rock handling and transportation. All hydraulic hoisting system components are proven. The only risk area is the wear rates of the valves and piping. Current estimates are based on gold ore. The business cases investigated show that the financial viability of the installations are not sensitive to wear rate. Hydraulic hoisting is technically feasible and financially attractive for platinum mines. Keywords: hydraulic hoisting, slurry

Jan 1, 2005

By M. van Biljon

The possible closure and subsequent flooding of South Deep Gold Mine?s neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding South Deep mine. Several technical investigations had been carried out before and during construction of the plugs in order to reduce the probability of groundwater flow through the boundary pillar between the two mines or through the rock mass immediately around the plugs. This paper describes the geological, hydrogeological and stability investigations carried out to evaluate the structural competence of the boundary pillar.

Jan 1, 2006

By R. Samuels, R. Klimpel

"IntroductionLaboratory and industrial grinding tests have shown that the process of size reduction of metal containing ores can be significantly influenced by chemicals added to the slurry being ground.,The terms grinding aid or grinding additive refer to a substance which, when mixed into the mill contents, causes an increase in the rate of size reduction. The increased rate can be used to grind a higher feed rate to the desired product size or it can be used to produce a finer product size at a fixed rate. Whether the use of a grinding aid is justified in any given situation depends on the cost of the substance versus the improvement of output or product quality obtained with its use.A wide variety of grinding additive mechanisms have been suggested in the general mining literature (1,2,3,4,5,6,7). The prevention of particle agglomeration, slurry cushioning of grinding media impact, grinding media coating, changing the strength of macro porous rocks, and chemical adsorption on flaw surfaces to change bonding forces and surface energy have all been suggested. More recently, some grinding additive work has been carried out (8,9,10,11) which suggests that the use of efficient chemicals to control the fluidity of dense slurries is a viable economic approach to achieve improved grinding rates. These increased grinding rates are achieved with no increase in power to the grinding mills and apparently with no increase in media consumption costs. Unlike much of the previous work with grinding additives, this recent work is accompanied by a rather complete engineering characterization and prediction of performance capability. The chemicals involved were chosen so as to efficiently control the viscosities of slurries under conditions of high shear yet not adversely affecting flotation, flocculation, and other downstream surface chemistry operations."

Jan 1, 1979

By G J. Corbett, P Magner, M McKenzie

Structures formed during ductile deformation have been reactivated during the later brittle mineralisation process. Two generations of folding are classified as: early recumbent megascopic FI folds and FI shears which transpose the hinge regions, and later upright F2 folds. S1 is folded about F2 folds which contain axial planar S2 crenulation cleavage. Vergence relationships between S1 and bedding indicate that many of the mineralised structures occupy sites of FI folds which have acted as plumbing systems for later gold mineralisation (eg Blackwater mine). The Globe-Progress gold mineralisation is localised by a major jog formed by sinistral strike-slip movement on two FI fault segments and mineralisation also occurs in smaller jogs along strike (eg Sir Francis Drake, Happy Valley-Merrijigs, Cumberland). &nbsp; The lodes of ribbon quartz which exploit the FI shears and local bedding planes, are inferred to have mostly formed after the peak of metamorphism, possibly related to the emplacement of Carboniferous granites. This was followed by a sequence of vein deposition and wallrock alteration which consists of quartz-As/Fe sulphides ? carbonate - stibnite ¦ trace base metal sulphides and Bi-sulphosalts ? illitic clay/sericite-chlorite. Gold at Globe-Progress is mainly encapsulated in arsenopyrite. At Blackwater, free high fineness gold occurs in partings in lode quartz with late sericite-chlorite. The above sequence of events is comparable to that encountered in many intrusion-related gold systems throughout the Southwest Pacific region. There is a spatial relationship between gold mineralisation and dykes variably described as diabase, dolerite or lamprophyre. Alkaline rocks occur in many Pacific rim and older goldfields and may possibly be related to a magmatic source for gold mineralisation.

Jan 1, 1997