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By Maike Von Heymann, Sergio González, Gaelle Dupuis, Ignacio Ishizawa, Claudia Toledo

Anglo American es una compañía minera global líder que cuenta con productos componentes esenciales en casi todos los aspectos de la vida moderna. Nuestro portafolio de operaciones competitivas de primera clase, con una amplia gama de futuras opciones de desarrollo, proporciona muchos de los metales y minerales esenciales para un mundo más limpio, ecológico y sostenible, y que cumpla con las demandas diarias de los consumidores. Como parte de la implementación de nuestro plan de minería sostenible impulsamos la implementación de las plataformas de desarrollo colaborativo, que en el caso de Moquegua se denomina Moquegua Crece.

Sep 29, 2023

By K. Lombard

"‘Roof support awaiting time’ (RSAT) is a term used at Goedehoop Colliery’s Simunye Shaft to describe the potential production time lost due to the continuous miner (CM) standing idle waiting for roof support to catch up. Investigations revealed that in 2013, Simunye Shaft had approximately1400 hours of RSAT, which suggests that the mine could have potentially produced an additional 280 000 t of coal. This project consisted of two parts. Firstly, the causes of the high RSAT and means to improve the situation were investigated. Secondly, as insisted by mine management, the CM cutting sequence was investigated as a possible cause of high RSAT. Machine-related challenges due to the roofbolter installing support too slowly, geological conditions (mostly hard roof conditions and slips),logistical challenges pertaining to the CM cutting sequence, man-related challenges related to operator fatigue, re-support, operator inexperience, and the absence of support targets were identified as main contributors to RSAT. Furthermore, results showed that the roofbolters in the sections at Simunye Shaft are slower than the CMs. A target of 28% reduction in RSAT was set. Experts from Kennametal and Fletcher were consulted to find solutions for the identified causes. In total, eight solutions for RSAT were identified, but the solution that contributed most significantly to reducing RSAT was to use hard roof drill bits as a standard product at Simunye Shaft. Calculations showed that by using hard roof drill bits, RSAT can be reduced by 43%, which is more than the specified 28% target. The cutting sequences at Kriel, Greenside, and Simunye Shaft, togetherwith three newly developed cutting sequences, were simulated using the UCMS (Underground Coal Mining Simulation) program. A re-aligningprinciple was incorporated into the newly developed cutting sequences toalign the cutting sequences to general support work and to reduce RSAT. A decision matrix revealed that a cutting sequence in which boxing takesplace in R3 (third road to the right of the belt road) and in which the re-aligning principle has been incorporated will be the best option for Simunye Shaft. The recommended cutting sequence will lead to a 5% increase in production.The work presented in this paper was carried out as partial fullfilment for the degree BEng (Mining Engineering)"

Jan 1, 2015

By Feilding C

Vitrinite of humic source (often designated as vitrinite A) is the maceral by which the rank of a coal ought to be determined. Therefore its recognition, and the precise identification of other vitrinites is essential. The majority of Australian petrologists are not differentiating between the vitrinite group macerals in maturation studies, the results of which have led to unexplained phenomena in coal characterisations and evaluation, such as 'reactive inertinites' and inaccurate predictions in petroleum source rock studies. The Callide coal has been chosen as a case study, with examples from other coals. The coal seams from the Callide Coal Measures show variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56 per cent, and a range of 05. - 0.7, implying a higher rank than the 0.49 per cent Ro total vitrinite reflectance recorded in previous publications. Vitrinite B is one of the most commonly-occurring macerals in the Callide coal. The lower-reflecting vitrinite B which forms bands, often several hundred microns in thickness, in TEM appears to be electron transparent lipid rich. Vitrinite B is interpreted to represent accumulations of leaves, and is believed to be a major source of hydrocarbons in Australian sedimentary basins. The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from the amber to light brown fluorescence of exinite and the presence of exsudatinite in cell cavities and cleats. However vitrinite B, the major potential source of oil, is seen under the microscope to be generating oil, thus placing this coal at the top of the oil window. Micrinite, the origin of which has been much debated, occurs as cell filling or infill of spaces between laminations in vitrinite B.

Jan 1, 1991

By C Fong

Compliance Planning is an active approach to ensure mining operations align more closely to their longer-term plans. Through Compliance Planning, operations can not only measure their performance on intervals as short as intra-shift, but they can then apply corrective measures to ensure they remain as close as possible to the plans. Compliance Planning targets short-term and execution level teams, as these are the shortest duration planning divisions commonly found in mining operations. Compliance Planning combines live information with intelligent planning capabilities to provide a framework that enables mining operations to realise a significant improvement in reconciliation of plan to actual movements.

Jun 22, 2022

By J. Mastoris

The growing environmental awareness and the need for providing social service to the community, urge the primary sector companies (such as mining) to find new solutions, by adjusting their operations with the special, local conditions and meeting everyday problems in practical ways. We hereby present a real case of re-design of an open pit, closed-bench type industrial minerals (clay) excavation, for the purpose of rehabilitation and utilisation as a water reservoir. The potential use of rainfall water was studied on the basis of covering the irrigation needs and improving the living standard of the neighbouring farmers and also as a project or recreational development of the area by shaping a wetland. The experience from the project progress and the reservoir use has been positive to date and the reclamation plan seems to have the acceptance of the local community.

Jan 1, 2002

The area around Big Bell was actively explored and sporadically mined for gold from 1904 onwards. The lease was named Big Bell in 1913. The property became established as a major mining centre with the development of the Big Bell underground mine in 1936. Mining operations commenced in late 1937 and ceased in January 1955, after milling 5.56 million tonnes of ore and producing nearly 21 tonnes of gold. In 1969 Australian Consolidated Minerals Ltd (A.C.M.) acquired the deposit then explored it alone and in joint venture until the current joint venture agreement with a subsidiary of Placer Pacific Limited (PPL) was negotiated in 1984. Following exploration and evaluation of near surface mineralisation, and a reassessment of the remnant pillars underground, the concept of a large open pit in conjunction with an underground mine evolved. The feasibility study was completed in October 1987, and the decision to go ahead was formally announced on 2nd December 1987. Placer Dome Technical Services Ltd were contracted to be the Project Managers, commencing construction on site early in January 1988 and handing the plant over to the operators 13 months later. The capital cost of the project at handover was estimated to be $133 million. The operating team commenced pre-production stripping of the open pit on 1st May 1988. By 31st January 1989 almost 16.0 million tonnes had been stripped and 350,000 tonnes of ore stockpiled.

Jan 1, 1989

By C. Fleming, J. R. Goode

ABSTRACT: Data were produced from two uranium project studies that were conducted in 2008, both involving uranium recovery from leached slurry by resin-in-pulp (RIP) with strong base resins. In both studies, excellent metallurgical results were produced. The loaded resins were eluted with strong sulphuric acid and recycled through RIP circuits in an integrated process. Resin losses by either abrasion or mechanical breakage were immeasurably low. Metallurgical results from these two campaigns are presented, along with a case study economic analysis of RIP versus the alternative processes of counter-current-decantation or filtration and solvent extraction.

Jan 1, 2011

By S. Shankar

Available literature on the effect of re-entrainment on overall airborne dust concentration in mine airways or the fundamental mechanisms of coal dust re-entrainment in mine atmosphere is scant. Therefore, as part of the Respirable Dust Center's ongoing research, a three part study was envisaged: study of the re-entrainment phenomena of anthracite and bituminous coal dust particles in a wind tunnel under the influence of varying air velocities; study of the same in the Lake Lynn Laboratory Mine of the USBM with both airflow and walking by personnel causing re-entrainment; and mathematical modeling and computer simulation of the re-entrainment phenomenon. In this paper, results from the re-entrainment studies in the wind tunnel and the Lake Lynn Laboratory Mine are presented. Further, the results from the wind tunnel studies are compared with the results from in-mine studies conducted at the Lake Lynn Laboratory Mine of the USBM. Comparing the results from the two studies it was observed that increasing air velocity increased the rate of re-entrainment, but increased time of exposure decreased the airborne dust concentration. Compared to same size particles, a mixture of sizes created more airborne dust concentration when re-entrained. It was also observed that contribution of airborne dust concentration due to airflow was negligible compared to the contribution due to walking.

Jan 1, 1995

By R. V. Ramani, S. Shankar

"Available literature on the effect of re-entrainment on overall airborne dust concentration in mine airways or the fundamental mechanisms of coal dust re-entrainment in mine atmosphere is scant (Shankar and Ramani, 1991 ). Therefore, as part of the Respirable Dust Center's ongoing research, the following three-part study was undertaken:• a study of the re-entrainment phenomena of anthracite and bituminous coal dust particles in a wind tunnel under the influence of varying air velocities;• a study of the same in the Lake Lynn Laboratory Mine of the USBM with both air flow and walking by personnel causing re-entrainment; and• the mathematical modeling and computer simulation of the re-entrainment phenomenon.In this paper, results from the re-entrainment studies in the wind tunnel and the Lake Lynn Laboratory mine are presented. Comparing the results from the two studies,it was observed that increasing the air velocity increased the rate of re-entrainment ( Shankar and Ramani, I 994a) and the rate of re-entrainment decreased with the time of exposure of the source dust to the flowing air. In addition, when the source dust was composed of particles of different sizes, the airborne dust concentrations due to re-entrainment were higher than when the source dust was composed of particles of the same size. The contribution of airborne dust concentration due to air flow was negligible compared to the contribution due to walking. IntroductionIn underground coal mines, dust is produced primarily during the process of mining and during such activities as pillar spall, loading, belt transfer and roof fall. The generated dust is entrained and then collects on surfaces through dispersion, diffusion and eventual deposition. Removal forces, such as flowing ventilation air or turbulence caused by walking and moving vehicles, can re-entrain the deposited dust (Hall, 1955). A portion of the re-entrained dust remains airborne and increases the concentration of airborne dust in mine airways.The presence of airborne coal dust in mine airways in large concentrations can be hazardous. Health effects include coal workers' pneumoconiosis (CWP) and silicosis, and it can be a nuisance affecting visibility. In addition, as is common during methane explosions, if the concentration of airborne coal dust becomes significant, there could be a coal-dust explosion (Singer, Cook and Grumer, 1972; Singer, Harris and Grumer, 1974; Edwards and Ford, 1988). Through concerned research efforts over the last decade, significantprogress has been made in reducing the airborne dust concentration in mine atmospheres. However, secondary sources, such as re-entrainment, have not been studied in-depth. It is important to understand the phenomenon of re-entrainment and its potential contribution to the airborne dust concentration in mine airways for further decreasing airborne dust hazards in mines."

Dec 1, 1996

By R. V. Ramani, S. Skankar

Available literature on the effect of re-entrainment on overall airborne dust concentration in mine airways or the fundamental mechanisms of coal dust re-entrainment in mine atmosphere is scant (Shankar and Ramani, 1991). Therefore, as part of the Respirable Dust Center's ongoing research, the following three-part study was undertaken: •a study of the re-entrainment phenomena of anthracite and bituminous coal dust particles in a wind tunnel under the influence of varying air velocities; •a study of the same in the Lake Lynn Laboratory Mine of the USBM with both air flow and walking by personnel causing re-entrainment; and •the mathematical modeling and computer simulation of the re-entrainment phenomenon. In this paper, results from the re-entrainment studies in the wind tunnel and the Lake Lynn Laboratory mine are presented. Comparing the results from the two studies, it was observed that increasing the air velocity increased the rate of re-entrainment (Shankar and Ramani, 1994a) and the rate of re-entrainment decreased with the time of exposure of the source dust to the flowing air. In addition, when the source dust was composed of particles of different sizes, the airborne dust concentrations due to re-entrainment were higher than when the source dust was composed of particles of the same size. The contribution of airborne dust concentration due to airflow was negligible compared to the contribution due to walking.

Jan 1, 1996

By Raja V. Ramani, Sachin Shankar

"Re-entrainment refers to dislodgement of particles deposited by both atmospheric and nonatmospheric processes and their subsequent insertion into a flowing field. Formation of sand dunes, snow drifts, soil erosion and fugitive dust emissions are a few examples of the natural occurrence of re-entrainment. Re-entrainment studies have been done for the estimation of potential hazards from nuclear fallouts. The phenomenon of re-entrainment has been utilized for the cleaning of wafers and filters. Re-entrainment is associated with both surface and underground mining activities. However, studies on dust re-entrainment in mine atmospheres are limited. Understanding the re-entrainment phenomenon is important because dust particles lying seemingly harmless on the ground and adhering to numerous surfaces can get re-entrained and become a health and safety hazard.There are significant differences in the kind of re-entrainment encountered in underground mines and those in other fields of interest. These major differences are air velocity, direction of air flow, particle size, amount of particles, and time of exposure. While numerous studies have been done in other fields to identify the role of interacting variables and their contribution to the mechanisms of re-entrainment, no similar reported work is available for dust in mine atmospheres.In this paper, recent research efforts on re-entrainment are reviewed. The most suitable form of representing re-entrainment in underground coal mine atmosphere is presented. Various approaches to studying re-entrainment phenomenon in mines are also outlined.In the mineral industries, formation of dust particles of widely varying sizes is a natural outcome of the fragmentation required in mining the solid resources. Fine particles in mine atmospheres, particularly in the respirable size range, are a threat to the health and safety of the miners when present in high concentrations. In 1980 the National Academy of Sciences (NAS) Committee on the Measurement and Control of Respirable Dust in Mines recommended that the spatial and temporal characteristics (of fragments produced in coal mining) need to be understood so that the exposure of workers to the dust can be controlled. Recently several studies have been performed to understand the fundamental behavior of the airborne respirable dust in mine airways (Bhaskar, 1987; Qin, 1988; Polat, 1989; Bode, 1990)."

Mar 1, 1992

By Raja V. Ramani, Sachin Shankar

Re-entrainment refers to dislodgement of particles deposited by both atmospheric and nonatmospheric processes and their subsequent insertion into a flowing field. Formation of sand dunes, snow drifts, soil erosion and fugitive dust emissions are a few examples of the natural occurrence of re-entrainment. Re-entrainment studies have been done for the estimation of potential hazards from nuclear fallouts. The phenomenon of re-entrainment has been utilized for the cleaning of wafers and filters. Re-entrainment is associated with both surface and underground mining activities. However, studies on dust re-entrainment in mine atmospheres are limited. Understanding the re-entrainment phenomenon is important because dust particles lying seemingly harmless on the ground and adhering to numerous surfaces can get re-entrained and become a health and safety hazard. There are significant differences in the kind of re-entrainment encountered in underground mines and those in other fields of interest. These major differences are air velocity, direction of air flow, particle size, amount of particles, and time of exposure. While numerous studies have been done in other fields to identify the role of interacting variables and their contribution to the mechanisms of re-entrainment, no similar reported work is available for dust in mine atmospheres. In this paper, recent research efforts on re-entrainment are reviewed. The most suitable form of representing re-entrainment in underground coal mine atmosphere is presented. Various approaches to studying re-entrainment phenomenon in mines are also outlined.

Jan 1, 1991

By N. Myung, G. Hwang, H. Kim, Y. Han, S. Choi

"According to research presently being conducted on selective lithium recovery in seawater, inorganic adsorbents with high selectivity and capacity for capturing lithium ions from liquid lithium resources are called lithium ion-sieves (LISs). Their low toxicity, low cost and high chemical stability make LISs suitable for lithium recovery from seawater. In the present study, the ultrathin LMO nanofibers with controlled diameter were successfully fabricated by an electrospinning technique with a hypothesis that greater aspect ratio (i.e., smaller diameter) would lead to the enhanced recovery of lithium ion from seawater. Design of Experiment (DOE) and dimensionless analysis were performed to systematically optimize the diameter and morphology of nanofibers. Several complementary techniques including FE-SEM and XRD were used to evaluate the physical/physicochemical properties of the nanofibers. Lastly, the lithium ion recovery was tested for the nanofibers with different physical properties using lithium ion solution. INTRODUCTION Demand for lithium resources is increasing in many industries across the world.1-2 However, the conventional resources for lithium is very limited, and it even gets worse to secure the resources due to low grade and/or complexity of feed materials. Much effort has been, therefore, devoted to obtaining lithium from aqueous lithium resources. Several methods such as solar evaporation3-4, co-precipitation5, and solvent extraction6 have been proposed for recovering lithium from an aqueous lithium source, but there are limitations on its use; It takes a very long time or conditions such as temperature, pH and Mg/Li ratio are severe. Lithium ion-sieve (LIS) materials are considered as a good lithium adsorbent because of their unique chemical structure that can selectively separate lithium ion from brine and seawater.7- 10 Furthermore, their low toxicity, low cost, and high chemical stability make LIS suitable for lithium recovery from aqueous lithium resources. Spinel hydrous manganese oxide (HMn2O4) derived from spinel lithium manganese oxide (LiMn2O4) after topotactically extracting lithium from the spinel structure by acid treatment is most widely investigated LIS.10, LIS materials have been actively studied in various forms for easy handling and high efficiency (i.e. membrane11,12, foam13-14, granular15,16). Among them, the 1-D nanostructure LIS with high specific surface area is excellent in efficiency.9 In this study, we present the part of our recently submitted work17. Specifically, we fabricated systemically lithium manganese oxide nanofibers with different diameter as a lithium ion adsorbent using electrospinning technique through design of experiment (DOE). Enhanced lithium ion adsorption properties of the HMn2O4 nanofibers with different diameter were investigated in lithium liquid resources."

Jan 1, 2018

By J. A. Vallejos

Re-entry protocols are a tactical approach for controlling risk after blasts or large events in seismically active mines. Based on the results of a survey on 18 seismically active mines, mostly in Ontario, current re-entry practices are summarized. Over half of the mines in Ontario use event decay rate analysis as their primary re-entry decision making parameter. We study in detail the applicability of the Omori?s law as an equation for describing the event decay rate for more than 250 mining-induced aftershock sequences in seven different environments. Practical guidelines for the use of the Omori equation as a re-entry criterion are proposed.

May 1, 2009

By M. I. Mabala, B. P. Watson, M. J. Kanda

A failed and stable Upper Group 2 chromitite pillar database was collected in 2007 as part of the PlatMine 1.2 pillar strength project. The database consisted of 177 pillars, of which 33 had failed. Most of the data were collected from various intermediate-depth mines near the town of Thabazimbi. Spans between rows of chain pillars were about 30 m. Pillar loads were estimated using pseudo-3D, elastic, boundary element modelling software. The pillar-load data were evaluated using a maximum likelihood regression analysis to determine strength parameters, following a similar approach to historically acceptable practice. The original formula was named the PlatMine Formula. This paper describes re-evaluations of the database, using a linear formula and several variations of the power formula. The formula providing the lowest standard deviation to the data in the database was considered the best representation of the pillars in the database. Through this rigorous process, a new formula for peak pillar strength was developed for Upper Group 2 chromitite pillars, which is unaffected by volume. The small standard deviation provided by this formula suggests a reliable relationship between strength and w/h ratio, in the w/h ratio range between 1.5 and 4.7. Accuracy, precision, and recall analysis confirmed the efficacy of this equation to the data in the database. Importantly, the new formula provided in the paper does not predict a significantly different strength to the current PlatMine formula, within the confines of the database.

Nov 27, 2024

By Larkin F, Farrer E, McGhie R. R

The Electrolytic Zinc Company of Australasia Limited commenced productive operations during February, 1936, at the- Rosebery and Hercules mines, which are situated near Rosebery, Tasmania. At this time it was decided that before re-organizing the steel sharpening shop a test should be made of the relative merits of conventional drill-steel and detachable bits. For this purpose Ingersoll-Rand type"I" thread centre hole.jackbits were selected and seventy-two of these were tested against conventional steel. Results indicated that, under the conditions pertaining at these mines, j ackbits should prove more economical than conventional drill-steel bits, and that a large-scale test, under working conditions, should be made. This was done by gradually replacing conventional drill-steel with jackbits at the Rosebery mine. Results were satisfactory and by the end of 1936 both mines were using only the jackbits.

Jan 1, 1939

By H. A. Steane

THIS PAPER describes the re-grind section in the 2,000-ton per day, lead-zinc flotation mill of Canadian Exploration Limited, near Salmo, B.C. There are two re-grind units in operation, one in the lead circuit, and one in the zinc circuit. In each unit, the rougher concentrate is re-ground ahead of the cleaning circuit. These re-grind units have made valuable improvements in the concentrate grade, and with no loss in recovery by over-grinding galena or sphalerite. Since the initial installation of this re-grind section, the plant throughput has been increased gradually from 1,600 tons to 2,000 tons per twenty-four hours, and, as shown by the screen analysis of mill tailing, a coarser overall grind has been accepted, from 55 per cent to 45 per ?cent minus 200 mesh. There has been no increase in grinding capacity, but two mills have been taken from the main grinding circuit and used for the re-grind circuit.

Jan 1, 1958

By D Price

Mining at the Tuckabianna Mining Centre in the Murchison district of Western Australia ceased in 1997, after the production of 550 000 ounces of gold at an average grade of 2.5 g/t from 22 separate open pits (Tectonic Resources, 2006). Like many historic mining camps in WA, Tuckabianna was considered exhausted of gold, such that an economic project could not be sustained on the existing resources. Since 1997, three separate companies have owned the Tuckabianna leases. Each of these companies completed minor exploration and some form of mining study to determine if mining could be sustained. All three companies concluded that the remaining resources were insufficient to support an economic project. Silver Lake Resources acquired the adjacent Tuckabianna, Comet and Moyagee projects in 2007 with a combined resource base of 693 000 ounces of gold in 11 separate deposits. In September 2009, Silver Lake commenced exploration in the Murchison targeting extensions to the main resources at the three project centres and completing targeted regional exploration across the lease holding. At the same time, a detailed evaluation of all historic drill data was completed and all resources re-estimated. This has culminated in the resource base increasing to 1.5 million ounces of gold in 20 separate deposits, with two new discoveries being made. In August 2010, a mining feasibility study was commissioned. Preliminary results from the study indicate that an economic stand alone project can be sustained for a minimum of five years. The ability to bring the remaining resource from a once unloved project into production is due to a number of factors: historically high gold price, combining adjacent projects into a single operation, evaluation of all resources regardless of size and grade, and well funded exploration directed to both resource extensions and new discoveries. Using the Tuckabianna Project as an example, this paper attempts to outline the strategy Silver Lake used to define the resources to justify the capital expenditure required for production, and give a summary of some of the successes and failures made as the projects progress towards mining. Examples of where being too rigid and over exuberant have resulted in less than optimal use of expenditure are used to high-light the difficulties in exploring in mature terrains. Evaluation of the success of a company’s exploration strategy at all scales from project acquisition to target selection is critical to the success of future project development. This paper has been part of that process for Silver Lake with some interesting discussions and insights being made. It is hoped that some of the points discussed can be applied to other projects to help achieve the best outcome from the assets available to a company.

Aug 22, 2011

The Mt Lyell Mine at Queenstown, Tasmania was re-opened in 1995 by Copper Mines of Tasmania Pty Ltd, a wholly owned subsidiary of Mt Lyell Mining Co Ltd. The re-opening followed over 100 years of copper and gold mining at Mt Lyell. Major changes in practice were implemented across the site. Preventing further damage to an already disturbed environment was a major priority. Sublevel caving, at a lower cut-off grade, replaced open stoping for the deep underground mining. Development and later stoping are handled by a contractor, National Mine Management Pty Ltd, in the largest underground contract awarded at the time. Large scale sublevel caving was new to Mt Lyell and not widely practised in Australia, requiring studies and systematic development of the method, particularly in drilling and blasting. Rehabilitation and upgrading of mine infrastructure have been and will continue to be a challenge. The mine has, since 1995, returned to being a stable producer with potential for growth.

Jan 1, 1998

By Frith RT, M D. Goodz

Drilling has been accepted as a major exploration tool. However its use in mine planning and development has been overlooked.This need for drillhole data was highlighted during the redevelopment boom of the central Victorian gold mines. During the 1980's numerous old mines were evaluated and successfully drilled to yield mineable parcels of quartz reefs close to existing workings.Invariably the initial decision was always to attempt reopening and rehabilitating existing access. The four case studies described have proceededsufficiently to show that major cost savings would have been made if underground drilling had been used as the main tool in mine planning.Savings not only in expenditure, but in the time required to make key decisions. In two cases the mines would have experienced far earlier expansions in production. In one case the mine would be currently producing rather than awaiting further finance. In the fourth example, the decision to case development would have been much earlier providing capital to other projects.

Jan 1, 1990