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By S. H. Badenhorst

Zacharias Lewala discovered a diamond at Grasplatz, near Lüderitz in April 1908. While this stone may not have been the first diamond to be found in this barren, inhospitable area, it most certainly was the stone that set off a chain reaction ultimately leading to the creation of Namdeb as we know it today. [ ]

Jan 1, 2003

By C. W. Reno

"THE LORNEX MINING PROJECT is one of several large-tonnage, low-grade operations recently placed in operation in British Columbia. It is located in the Highland Valley in the south central portion of the province. This area is described as a divide valley at an elevation range of 4,000 to 6,000 feet and is situated on the divide between two drainage systems. The major drainage to the west flows into the Thompson River and to the east and south the drainage enters the Nicola River system. This open-ended valley lies between low, rounded mountains in fairly heavily-wooded country. Prior to the commencement of copper mining activities, the first by Bethlehem Copper Corporation Ltd. over ten years ago, the valley was only sparsely settled. A few small ranches were in existence on the several Indian Reserves located along the valley bottomland. There has also been a small amount of logging activity in the valley, although much of the area is covered by dense lodgepole pine which has little or no value to the loggers. As the mining interest mounted with further discoveries of the disseminated copper ore typical of the district, much of the valley was covered with mineral claims and exploration drilling was carried on by several companies at various times. At the time Lornex was preparing to commence major construction work in early 1970, there was very little activity of any kind in the Highland Valley outside of the Bethlehem operation and a small amount of ranching."

Jan 1, 1973

By R. V. Ramani

This report, Volume I of the seven-volume Final Report on the U. S. Bureau of Mines research contract no. G0254030 titled Application of a Total System Surface Mine Simulator to Coal Stripping with the Pennsylvania State University provides an executive summary of the purpose and scope, objectives and results of the research. The remaining volumes of the Final Report, listed below, describe in detail model development, input and output documentation and the three case studies. Under the project, an existing surface mine simulator, Open-pit Materials Handling Simulator (OPMHS) was modified and extended for application to surf ace coal mining. In addition, two equipment selection models, and a cost model were also developed. Volume II: OPMHS User's Manual Volume III: Equipment Selection Models Volume IV: Surface Mining Cost Model Volume V: Application of OPMHS to an Illinois Mine Volume VI: Application of OPMHS to a South Eastern Ohio Mine. Volume VIII: Application of OPMHS to a South Western Mine.

Jan 1, 1978

By Baogui Yang, Jie Yang, Anthony Iannacchione

"The cemented coal gangue-fly ash backfill technique (CGFB) has commonly been used to control subsidence damage caused by underground coal mining. This paper discusses the CGFB backfilling process used at the Xin-Yang coal mine, Shanxi Province, China. A general description of the components of the CGFB are provided. The reaction of the strata to the backfilling process is simulated with a scaled physical model based on the Xin-Yang conditions and verified with subsidence points on the surface. With the help of the cemented filling materials, the CGFB produces only a slight bend to the overburden roof strata over the longwall panel. Physical models were constructed at the China University of Mining and Technology, Beijing, to simulate actual conditions. The modeling results show minor fracture distribution in the overlying strata and lower abutment pressure development within the backfilling area. The effectiveness of the CGFB technique is verified by a reduction in the vertical surface subsidence measured above the backfilled area.INTRODUCTIONUnderground longwall mining is the most efficient underground means to recover coal resources and is used widely in China, the US, Australia, and Europe. However, this type of mining has introduced some serious environmental impacts. Perhaps the most significant environmental issues are the surface and groundwater impacts associated with the formation of the subsidence basin (Bell and Donnelly, 2006). Backfill technology has been used for years to mitigate subsidence impact. Simply speaking, the backfilling technique places filling materials into the void left from the extraction of coal. When this material is placed within the gob, it is capable of partially supporting the overburden until a new equilibrium is reached. Essentially, the backfill material inhibits crack development and expansion caused by the strata movement and mitigates damaging ground deformations.The cemented gangue-fly ash backfill (CGFB) is one type of novel backfill technology, consisting of cement, coal gangue, fly ash, water, and additives in varying concentrations. The CGFB is mixed on the surface, pumped underground through a pipeline as a slurry, and placed in the void behind the longwall shield under the protection of specially designed hydraulic supports."

Jan 1, 2018

By Uwe König

Traditionally quality control of iron ore sinter, its raw materials and raw mixtures has relied on time-consuming wet chemistry. The mineralogical composition that defines the properties is often not monitored. XRD analysis in combination with Rietveld quantification and statistical data evaluation using Partial Least-Square Regression (PLSR) has been successfully established to determine the mineralogical composition and process parameters such as the FeO (Fe2+) content and basicity of iron sinter within an analysis time of less than 8 minutes per sample. Both methods take the full XRD pattern into account and can be simultaneously applied on the same measurement. In addition the Rietveld method was used to quantify the phase content of raw mixtures to monitor the composition of blending beds.

Aug 16, 2017

By Glenn Norris, Tyler Buckingham

"Gold recovery gains in the order of one to two percent have been realized in 2009 due to changes in the operation of the grinding circuits at Barrick Gold Corporation’s Hemlo - Williams Mill. The initiative known as “split milling” involves milling low grade open pit ore in one grinding circuit and higher grade underground ore in the other grinding circuit under different conditions.The philosophy of split milling involves processing higher grade underground ore at a lower throughput rate and a finer grind while milling lower grade open pit ore at a higher throughput rate and a coarser grind. Bench scale tests showed that the recovery relationship for underground ore sources was much more grind sensitive than that of open pit ore. This relationship proved to hold in the plant. The gold recovery gain due to finer grinding of the higher grade ore is much greater than the recovery loss due to coarser grinding on the lower grade ore. Since the majority of gold is being recovered at a higher rate, this results in higher overall plant gold recovery when compared to the traditional operation philosophy of blending the ore sources.The challenges for achieving the maximum benefits of split milling were two fold; the need to increase throughput on the open pit ore milling circuit and a means of grinding finer on the underground circuit. The former was met with an increase in SAG (Semi-Autogenous Grinding) mill ball charge, a basic “drill to mill” blasting campaign and changes to the primary gyratory crusher. The latter was met with a reduced SAG mill ball charge and a higher milling density. The resulting benefits in additional gold recovered are in the order of $3-5 million per annum.INTRODUCTIONThe Williams Mill processes ore from three different ore sources, the David Bell Mine (DB), the Williams Underground Mine (WUG) and the Williams Open Pit (OP). All three ore sources are located within the Hemlo camp in Northwestern Ontario adjacent to the Trans-Canada Highway. The Williams Mill was built in the mid 1980’s at which time it was designed to process 3,000 dry metric tonnes per day through a 22’ SAG mill in series with a 16’ ball mill. In 1988 a Mill expansion doubled the mill capacity by adding a second identical grinding circuit. A photo of the current grinding circuit can be seen in Figure 1. Today the Williams Mill processes an average of 8,000 tonnes per day of which approximately 60% is from the Williams Open Pit."

Jan 1, 2010

By George Munro

New Zealand is a small, almost pristinely pure country environmentally speaking. It is blessed with an abundance of clear waterways, lush green vegetation and fresh clean air. It is a country in which agriculture and forestry predominate, and mining developments have to be introduced prepared to answer in considerable detail the question "How will this proposal affect the New Zealand environment as we know it today". Those who make the legislation have the difficult problem of establishing standards at a level which will maintain as far as possible the status quo without unduly inhibiting the developments currently approaching the starting line. We have been fortunate in some sense in that since the demise of the early gold rush days by the 1920's, little mineralisation of a complex nature has been uncovered in New Zealand. Coal fields have been developed in the central North Island, and on the West Coast and Southland regions of the South Island. A ban on large scale open cast mines in the Coromandel area has restricted mining in that highly prospective area, although three large gold prospects have got underway elsewhere in the last three years. There is no other ore processing being undertaken at present. Some recent proposals involving lead, gold and silver in complex arseno­ sulphides have failed to get the necessary approvals and have been discarded. Our ore processing problems are therefore straightforward ones, and confine themselves to acid drainage, mercury handling and disposal, and cyanide.

Jan 1, 1991

By F. Calizaya

The PT Freeport Indonesia‘s Deep Ore Zone(DOZ) copper deposit is located in the province of Irian-Jaya, Indonesia. Currently, a block cave mine is being developed around this deposit. Production is scheduled to start in year 2000 and to ramp up to25,000 tpd by year 2003. The air quantity requirement for this mine is equal to 780 m3/s. To supply this quantity, the mine will require five centrifugal fans (one 450 and four 750 kW fans). This study summarizes the technical aspects related to the installation and commissioning of one of these fans. The fan was installed on the surface in a parallel arrangement with two others. It has a design capacity of 240 m3/s of air at 2.2 kPa of static pressure. The study presents the installation details from the underground shaft excavation and portal development through fan testing and commissioning. It also presents the results of a monitoring system that was installed to determine the fan duties.

Jan 1, 2000

By Danfeng Xu

The majority of the world?s nickel (Ni) resources occur as laterite ores, which are exceptionally complex, lower grade (<1.5% Ni) and expensive to treat using conventional smelting and high temperature/pressure autoclave methods. Heap leaching is a promising, less costly, alternative technology for processing low grade nickel laterite ores. However, significant technical challenges remain with Nickel laterite heap leaching, preventing its general adoption. This paper presents some highlights of laboratory column leaching studies undertaken to characterise, evaluate and optimise sulphuric acid leaching behaviour of Nickel laterite agglomerates. They provide basic but valuable information regarding Nickel laterite agglomerate structure stability and leaching performance under industrially-relevant, continuous acid irrigation conditions. In particular, Nickel and other key metals? (e.g. Co, Fe, Al and Mn) extraction rates, free acid concentration, bed slump and structural changes were determined at a given acid percolation rate as a function of time. Potential implications of the findings, for devising strategies for improved Nickel laterite plant heap leach operations are discussed. Keywords: nickel laterite, column leaching, agglomerates, leaching kinetics, acid consumption

Sep 1, 2012

IN the construction of a set of ordinary mine plans, two axes or coordinates are used; also, two different projections are essential viz., a plan (horizontal projection) and longitudinal section (vertical projection). In isometric projection three axes are employed-one axis vertical and the remaining two inclined to it at angles of 120&#176;, also making an angle of 120&#176; with one another, as shown in Fig. 1. The two inclined axes are used to plot the horizontal projection, while altitudes are plotted on the vertical axis. As an illustration, consider the ease of a simple object, such as a box. To show all the dimensions in the usual manner requires two drawings-a plan and elevation, as in Fig 2.

Jan 1, 1919

By A. G. Scobie

A spectrographic method for the determination of small amounts of gold and the platinum metals in ores has been developed. By means of this method, an assay of 0.001 ounce per ton on one assay ton samples is possible, and by seecrrographic adjustments the sensitivity may be increased to 0.0001 ounce per ton. All the prec10us metals may be determined from one spectrographic arcing with an accuracy of about 5 per cent average deviation from absolute values, and the complete analysis of an ore or similar product may be reported five or six hours after receipt of sample.

Jan 1, 1945

By G Britton, P Moynagh

As more than a few mines gradually sink under the weight of emails, whiteboards, notice boards and ever more complex spreadsheets, the holy grail of effective short-term interval planning and control in underground mines is as far away as ever. Despite the mining industry investing ever greater amounts in planning and Enterprise Resource Planning systems, short-term plans become ever more complex and rigid. What the industry desperately needs are not more ‘disembodied voices down the speaking tubes’, but flexible and effective planning systems that encourage people to make reasonable commitments to each other so that everyone can work as a coordinated team to complete the work required each shift.One solution to the challenge has emerged. This paper describes the ‘Fewzion’ shift planning and short interval control system which has been developed at Anglo American’s Moranbah North and Glencore’s Oaky Creek coalmines in Central Queensland. Fewzion has drawn on management theory embodied in Management Operating Systems, Lean and Theory of Constraints approaches to continuous improvement to play a key role in both mines achieving record breaking tonnages.In addition to explaining the Fewzion approach, a case study is presented describing how Anglo American’s Moranbah North improved production by 39 per cent in 2014/2015 and won ‘Coalmine of the Year’ two out of the last four years and how Glencore’s Oaky Creek sustainably improved monthly development meters by 34 per cent within two months of implementing Fewzion.CITATION:Moynagh, P and Britton, G, 2017. How a frontline planning and commitment system improves trust, commitment and results in operations, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 235–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Jianbo Hu, Tao Zheng, Zhao Qihua, Rui Su

Rock mass discontinuities play a significant role in evaluating the stability of rock slopes. It is necessary to collect and analyze these discontinuities to fully understand the mechanical and deformational behaviors of rock masses. Based on the digital images of some slope faces, this paper proposes a framework based on machine learning for detecting and extracting discontinuities. First, digital images and photo poses are combined, the original scene is reconstructed, and 3D point cloud data are obtained. All captured point clouds can be mapped with each image by the direct linear transformation algorithm. Next, the detection machine learning algorithm is used to segment rock mass discontinuities on 2D digital images. Finally, based on the mapping relationship, the 2D digital images that were segmented are transformed into 3D point cloud data. The geometric parameters of the corresponding discontinuities can be extracted by the DBSCAN and the Skmeans algorithm and the characterization of specific rules. The proposed framework was evaluated utilizing a quantity of slope digital images in the Yebatan hydropower under construction, located in Sichuan Province, China, as a case study. The results illustrate that most deviations are less than 10° for the dip direction and dip angle, which verifies the reliability of the proposed framework and maintains acceptable measurement accuracy.

Nov 6, 2022

Gas-liquid contacting in the packed bed is a common operation in metallurgical reactors. Research has shown that, unlike wetting flow, non-wetting liquid flows in the form of discrete droplets or rivulets. Thus, modeling of the liquid phase as a continuum is in contradiction to the observations. Also, for the non-wetting case, continuum models have failed to describe liquid flow path when the liquid source is a point source. The aim of the current work is to put forward a combined Lagrangian-Eulerian approach to model the liquid and gas flow in the packed bed. Liquid is assumed discrete and modeled using a force balance approach. Gas is assumed to be interpenetrating continua and modeled using k-emodel for turbulent flow. Structured packing is assumed and x- ray imaging technique is used to visualize liquid flow lines in the bed. Simulation results for liquid flow path compared with the experiments.

Jan 1, 2006

Jan 1, 1993

By Y Öztas, S McKinley, T Baker

The Kisladag Mine, Turkey, is a large porphyry gold deposit which is mined by open pit methods. In operation for over ten years, Kisladag provides an excellent example of how attention to a geologic feature, namely hydrothermal alteration, became a very effective predictive geological tool for planning and operation. The alteration domains were initially used as a geological tool to assist with establishment of resource model domains and to guide delineation drilling, but they were soon recognised to be correlative to geotechnical characteristics (affecting pit slope angles) and metallurgical performance (heap leach recoveries). Recent developments in spectral processing allow the systematic quantification of complex overlapping alteration phases and have greatly improved the ability to rapidly define internally consistent alteration domains for geotechnical and geometallurgical purposes.Alteration at Kisladag comprises a central core potassic (K-feldspar-biotite) zone, a tourmaline-white mica enveloping zone, an advanced argillic lithocap on the deposit’s eastern side and an overprinting pervasive argillic zone. These alteration zones and their distribution were based initially on strictly qualitative, visual mineralogical logging of diamond drill core. With the need for more accurate and consistent identification of the alteration mineral suites, particularly the phyllosilicate phases, logging was augmented by systematic measurement of spectral data using a Terraspec instrument.Recently the Kisladag spectral database (over 85 000 readings) was reprocessed by the newly developed methodology (aiSIRIS™) that allows relative quantification of the spectrally-responsive minerals. Visualising this transformed spectral mineralogy at various mineral concentration thresholds using implicit modelling software (Leapfrog&#174;) led to the creation of consistent mineralogical and alteration domains that are used for the definition of geotechnical and geometallurgical parameters. An implicit modelling workflow enables these domains to be easily updated as new data is collected while maintaining geological integrity of the model.CITATION:McKinley, S, Baker, T and &#214;ztas, Y, 2017. Alteration at Kisladag gold mine, Turkey – a progressive study in geology, geotechnics and geometallurgy, in Proceedings Tenth International Mining Geology Conference 2017, pp 51–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By L. S. Brooks

TIMBER HANDLING presents a problem for any mine where appreciable amounts are used. This problem is accentuated where the shaft compartments are too small to allow a loaded timber truck to be lowered in the mine cage. When Normetal Mining Corporation, Limited, found it necessary to resort to square-set mining it faced this problem of getting large quantities of timber down a shaft that was also required for hoisting ore. A &apos;timber car&apos; that could be suspended under the cage was developed to overcome this difficulty. Production started at the Normetal mine in 1937, at the rate of 250 tons per day. In 1938 a winze, known as No. 3 shaft, was sunk from the 800-foot level ?to the 1,385-foot level. This was later raised to surface and then deepened to 3,275 feet in three stages and became the main production shaft. The portion of the mine below the 3,070-foot level is serviced by a winze, locally referred to as No. 4 shaft, which has been developed for stoping down to the 3,990-foot level and which has been deepened to the 5,365-foot level. No. 3 shaft has two hoisting compartments, each 4 ft. 6 in. by 5 ft. 0 in. inside the timbers, through which the ?ore must be hoisted and timber and supplies lowered.

Jan 1, 1956

By Thomas E. Howard

Recently, the mining community has begun to move toward a more prominent place in the structure of American society. Extensive press coverage of our energy problems during the past year or two has led to an increasing awareness on the part of the public of the vital role that mining must play if today&apos;s standard of living is to be maintained. It appears that mining may be emerging from a status generally characterized in the public mind as an esoteric, dirty, man-killing, land- scape-despoiling endeavor, to a new stature that may eventually become as respectable as agriculture. To be sure, we are still being criticized, as has been the lot of miners since the time of Agricola. In fact, the clamor has never been louder. Nevertheless, the public, in increasing numbers, is beginning to know it needs us. But we cannot be complacent. Our improving stature brings along with it increasing responsibility. The mineral industry will be expected to produce mineral raw materials and fuels in ever larger amounts and sell them at reasonable prices, in the face of rising labor costs, decreasing labor availability, chacging labor attitudes, increasingly stringent environmental regulation, stricter health and safety standards, and a deteriorating geo-political climate.

Jan 6, 1975

By R. J. Pine, J. M. Rance, J. S. Coggan

ABSTRACT: The safe design of excavations created in a fractured rock mass is of paramount importance in rock engineering. Depending on the nature of the stress regime acting on an excavation, and the associated deformational behaviour of the rock mass surrounding the excavation, a number of potential failure mechanisms exist. These involve a combination of shear failure on existing joints, extension of critically oriented joints and propagation of new fractures through previously intact rock. Conventional numerical codes usually adopt either a continuum or discontinuum approach; this often results in significant over simplification and kinematic limitations particularly when modelling complex rock mass behaviour in the close vicinity of excavations. This paper describes the results from several case examples using a combined finite element-discrete element code, ELFEN that incorporates a crack propagation mode. Through the use of selected rock engineering examples, the authors demonstrate the potential of the code in the realistic simulation of complex rock failure both in underground and surface excavation applications. RÉSUMÉ: La conception sûre des excavations créées dans une masse de roche fracturée est d&apos;importance primordiale dans la géotechnique. Selon la nature du régime d&apos;effort autour d’une excavation, et le déformation associé de la masse de roche autour de l&apos;excavation, il exsite un certain nombre de mécanismes potentiels d&apos;échec. Ceux-ci comportent une combinaison d&apos;échec de cisaillement sur les joints existants, la prolongation des joints d’orientation critique et la propagation de nouvelles ruptures dans la roche précédemment intacte. Les codes numériques conventionnels adoptent habituellement l’approche, soit d’un continuum, soit de discontinuum; ceci a souvent comme conséquence une sursimplification significative et les limitations cinématiques en particulier en modelant le comportement complexe de la masse de roche très proche des excavations. Cet article décrit les résultats de plusieurs exemples de cas en utilisant un code qui s’agit d’une combination d’élément discret et d&apos;élément fini, ELFEN qui incorpore un mode de propagation de fissure. Par l&apos;utilisation des exemples choisis géotechniques, les auteurs démontrent le potentiel du code dans la simulation réaliste de l&apos;échec complexe de roche pour les applications aux excavations soit au fond soit à l’extérieure. ZUSAMMENFASSUNG: Das sichere Design der Aushöhlungen, die in einer zerbrochenen Felsenmasse verursacht werden, ist vom paramount Wert in der Felsentechnik. Abhängig von der Natur des Druckregimes, das auf einer Aushöhlung und dem dazugehörigen deformationalen Verhalten der Felsenmasse umgibt die Aushöhlung fungiert, bestehen eine Anzahl von möglichen Ausfalleinheiten. Diese beziehen eine Kombination des Scherausfalls auf vorhandenen Verbindungen, Verlängerung der kritisch orientierten Verbindungen und Ausbreitung der neuen Brüche durch vorher intakten Felsen. Herkömmliche numerische Codes nehmen normalerweise entweder ein kontinuum oder discontinuum Annäherung an; dieses ergibt häufig bedeutende Übervereinfachung und kinematische Beschränkungen, besonders wenn es kompliziertes Felsenmasseverhalten in der Nähe der Aushöhlungen modelliert. Dieses Papier beschreibt die Resultate von einigen Fallbeispielen mit einem kombinierten begrenzten Element - getrennten Elementcode, ELFEN, das einen Sprungausbreitungmodus enthält. Durch den Gebrauch von vorgewählten Felsentechnikbeispielen, demonstrieren die Autoren das Potential des Codes in der realistischen Simulation des komplizierten Felsenausfalls bei Anwendungen für beide Tagebaue und Untergrundsaushöhlungen.

Jan 1, 2003

By Ziebell, Howard A.

THE Washington magnesite deposits, located in the hilly and mountainous northeastern part of Washington, occur as massive lenses in a sedimentary series made up of dolomite, shale, and quartzite, into which basic dikes have intruded. The ore pattern resembles a series of disconnected chain links extending approximately 25 miles in a south-west direction. Magnesite in this district is all crystalline and closely associated with dolomite, talc, serpentine, and basic dike rock. All deposits which have been developed are near the surface so that quarry-bench mining has been possible. For over twenty years hand sorting magnesite ore at the quarry face was standard practice. Ore cars were hand trammed on 30-lb rail systems which led from the face to ore passes or raises for the magnesite ore and to the waste dumps for disposal of the rejected waste material. This system was somewhat modified by the use of Dempster Dumpster trucks. The ore was, however, still sorted by hand from the calcium and silica bearing waste rock. Power equipment. consisting of one 3/4-yd electric shovel, was

Jan 1, 1949