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By B. Schoevaerts

The ever-increasing depth of mineral extraction presents a challenging environment for hard-rock underground mines. High in situ stresses and associated seismicity with potential rockburst hazards are the major decisive factors contributing to the choice of a ground support regime. Conventional ground support systems, designed primarily for static loads, are not always capable of providing safe working conditions for underground personnel in seismically active mines. Systems specifically developed to resist dynamic loading and allowing for larger deformations are therefore preferred alternatives. High-tensile chain-link mesh has a proven record of successful use in open cut operations in various rockfall barrier installations due to its high energy absorption capacity. It has also been used in underground operations in various parts of the world. Its application in South African underground mining, however, is limited due to the high labour intensity. This paper describes a method of mechanized installation of a chain-link mesh as evaluation at Gold Fields' South Deep Gold mine situated some 45 km south-west of Johannesburg. A purpose-built mechanized roll mesh handler, developed in Australia, was used in this trial. The handler is compatible with all standard multi-boom underground drill rigs and is operated utilizing the hydraulic circuit normally used for the feed arrangement. A number of key performance indicators have been specified as success criteria by Gold Fields: ? A 30% faster installation compared to the conventional methodology ? The mesh should sustain any blast damage when applied to the blasting face ? No unravelling of the mesh when cut ? No failure of mesh under normal conditions ? Reliability of the MESHA® installation handler (availability >90% ? Compatibility of the MESHA® installation handler with AC 282 boomers. Although the energy-absorbing mesh combined with yielding rockbolts is a ground support system of choice for rockburst-prone conditions, the operational upsides recognized during the trial imply that this product can also be competitively used in less demanding ground conditions where weld mesh or shotcrete are customarily used as a primary surface support.

Jan 1, 2012

By D. F. Machuca-Mory

A change of support model consists of a procedure to change a stationary histogram at a small data scale to represent a larger scale; typically a distribution of sample drill-hole data is changed to represent a chosen selective mining unit (SMU) scale. Most grade variables average arithmetically. Thus, the mean stays the same for different scales, and the variance changes according to well-established theory using average variogram values. The longstanding challenge has been to predict how the shape of the histogram changes. The discrete gaussian model is widely used because it appears reasonable and introduces few artifacts; there are no artificial minimum/maximum values and the target mean and variance are reproduced exactly. The resulting distribution shape, however, is strongly dependent on a multivariate gaussian distribution. The authors generalize the approach by taking advantage of a property of the isofactorial model, which allows one to specify where the random function falls on the spectrum between a low-entropy mosaic model and a maximum-entropy diffusion model. A measure of dissemination (MD) is computed using a ratio of the madogram and the variogram. The change of support algorithm is developed that uses a variable measure of dissemination (VMD) that is easily calculated and fit to data from the deposit. The resulting VMD change of support model is very flexible to represent different mineralization styles encountered in practice; global predictions of recoverable reserves are more accurate and decision-making is improved. A number of real examples are shown to demonstrate the approach.

Jan 1, 2008

Virtual Reality (VR) simulations are excellent tools for training, education, simulation of abnormal and dangerous conditions in mines and solving complex problems. Although the concept of VR has been around for nearly half a century, it has taken recent advances in hardware and software to bring this technology to within the budgetary reach of ordinary users and researchers. VR is now successfully being used in the minerals industry for: data visualization, accident reconstructions, simulation applications, risk analysis, hazard awareness and training. The Institute of Sustainable Minerals Industry, Advanced Computer Graphics and Virtual Reality Research Group (SMI-VR) at the University of Queensland, established in late 2000, has been involved in developing VR applications for the minerals industry in conjunction with various research centres. This paper illustrates the benefits of using advanced computer graphics and VR techniques in the minerals industry with some examples of applications developed.

Jan 1, 2003

The mineralogy, textures, and genetic significance of a silver-rich siderite vein and an apparently co-genetic galena vein from the South mine, Broken Hill are discussed.Both veins cut sharply across the Main Lode Horizon and appear to be coeval with thc A.B.H. Consols lode.The minerals of thc siderite vein apparently result from the preferential leaching of silver from Main Lode Horizon ore with a demonstrable "breakdown series" commencing with tetrahedrite, passing through silver sulpho-salts, and ending with simple binary compounds or with elemental silver.The siderite vein has been deposited by metahydrothermal fluids along the lines of Schneiderhohn's "secondary hydrothermal" mineralization.

Jan 1, 1968

Flue dust from the sintering of base metal sulphides was leached to remove cadmium and arsenic. Leach liquor contained cadmium, zinc and small amounts of other base metals as chlorides. Results are reported of the use of a cation exchange resin Zeocarb 225 to separate the base metals from the arsenic. The resin was eluted with sodium chloride or sulphate to give a solution of relatively concentrated cadmium suitable for recovery by zinc cementation. The limited solubility of sodium sulphate presented some practical problems which were investigated. Another problem was the precipitation of lead sulphate in the resin during elution.INTRODUCTIONWhen lead-zinc sulphides are sintered prior to smelting, the gases passing to the flue are mainly uncondensable but contain a certain proportion of sublimates and dust particles which deposit in the flue or are carried, after condensation in the gas stream, to some form of dust extraction equipment.The recovered dust is a complex mixture of base metal sulphates, sulphites, sulphides, chlorides and oxides, the composition depending on the original concentrates. A large proportion of the cadmium and some of the arsenic originally in the concentrates finds its way to this flue dust, the treatment of which can be a convenient means of removing these elements and controlling their concentrations in the main lead-zinc smelter circuit. However, disposing of this material represents an appreciable waste of base metals as well as a serious toxicity hazard.Sulphide Corporation Pty. Ltd. was faced with this problem in planning the flow sheet of the new lead-zinc smelter at Cockle Creek, N.S.W. From a test run carried out on a pilot plant at Avonmouth, U.K., using a mixture of lead and zinc concentrates, a sample of dust was obtained for...

Jan 1, 1960

By Fredrick L. Johnson

The Bureau of Mines, under Congressional mandate, conducted a mineral survey on the Park Range WSA (Wilderness Study Area) in 1984 and 1985. The WSA, located about midway between Tonopah and Ely, encompasses 47,268 acres. No mineral resources were delineated, nor were workings found, during the investigation. There has been, however, exploration in and near the north end of the study area. ASARCO is actively exploring a block of 41 claims for hot-spring type, low-grade, large-tonnage gold deposits. Their claim block is almost entirely in the study area. The Morey mining district, 7 miles southwest of the study area, produced silver and lesser amounts of gold and lead sporadically from the mid-1860's through the mid-1960's. The WSA is underlain by Tertiary rhyolitic and latitic volcanic rocks and by Paleozoic sedimentary rocks. The Paleozoic rocks have been faulted, silicified, brecciated, and hydrothermally altered, and have anomalous concentrations of precious metals and pathfinder elements. Additional exploration in the north part of the Park Range WSA may lead to delineation of gold resources.

Jan 1, 1986

By Met M, Worner H. K

In pursuance of the investigation into the influence of various elements on the properties of lead during the past year, the effect of several elements on the creep rate of commercially pure lead has been investigated; a standard initial stress of 500 lb. per sq. in. having been adopted for comparison purposes. Other work which has been carried out indicates that the relative results of creep tests may be altered by varying the applied stress, but this aspect of the problem will need to await further investigations for itscomplete elucidation. The results obtained with dilute tellurium alloys are considered sufficiently interesting, and in some respects are so extraordinary, as to warrant publicatiorr at this stage.n must be realised however that, since the results obtained appear to be at variance with those said to have been obtained in practice and those previously published, the present investigation can only be considered as a contribution to our knowledge of the general problem.Consequently it is not considered advisable or necessary to offer detailed explanation of the results given. In fact, some features of the tests about to be described will need further investigation before an adequate explanation is possible.

Jan 1, 1936

By George J. Conroy

To provide data as a basis for proposed acceptance standards and procedures covering permanent splices in trailing cables, the Bureau of Mines conducted testing programs on the flexure life in flat types W and G dc trailing cable splices and ground conductors. Primary reliance was placed on laboratory testing, although some cross comparisons were made at manufacturers' plants and mine operations Besides providing data for acceptance standards and procedures, results of the program should promote the general improvement of commercially available splice kits.

Jan 1, 1977

By C Simpson

The Pilbara region of Western Australia is well known for its abundant exports of hematite-goethite deposits, which have been mined and exported since the 1960s. Magnetite has also been mined in Australia throughout this period, although historically of much lower production volumes (WA Iron Ore profile, 2016). Magnetite offers a source supply of material >66 per cent iron grade product, which is used as premium feed (predominantly pellets) to blast furnaces or specialised steel mills.The Iron Bridge project area contains outcropping magnetite and hematite banded iron formation (BIF), which within the region was recognised as having potential to host economic mineralisation during the 1960s. Development within the project area, however, did not commence until Fortescue Metals Group acquired the tenements based on a 2004 agreement, formed a joint venture with interested groups and then initiated an assessment for magnetite (rather than hematite) mining potential. The combined deposits now have an identified large mineral resource inventory, with test work demonstrating they are able to produce a magnetite concentrate of greater than 66 per cent Fe over an extended mine life. This concentrate would be suitable for forming pellets or feed for direct reduced iron products.The deposits form a singular orebody, approximately 12 km in length by 1 km in width and extending to depths beyond 600 m. The four main deposits are geographically separate and have subtle mineralogical differences, thought driven by the degree of deformation and alteration within each area.Definition of the stratigraphy, structure and key mineralogy of the deposits has been carried out through several stages of exploration and project development. This has also included recent mining and processing of more than 1 Mt of feed material to an on-site processing facility. This demonstrated at a production scale that dry plus wet processing techniques can efficiently separate the magnetite from the gangue minerals to form a suitable (marketable) product.Geometallurgical classification of the host stratigraphy has been carried out from analysing the high volume of quantitative data available for this deposit. This has allowed definition of mappable units within the fresh BIF to be used as a driver in mine scheduling, delivering optimal feed to the processing plant.Construction of mine and processing facilities is expected to commence once all technical risks have been addressed, market conditions are deemed appropriate and approval is given by the joint venture partners.CITATION:Simpson, C, 2017. The Iron Bridge magnetite deposits, in Proceedings Iron Ore 2017, pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

THE Great Cobar Company Limited owns 1100 acres of freehold, which include the Great Cobar Oopper Mine and smelters, the Cobar Gold Mine, the Cobar-Ohesney Copper Mine, and the Great Peak Gold Mines.ORE OCCURRENCEThe ore-bodies in the first three mines-namely, Great Cobar Copper Mine, Cobar Gold Mine, and Cobar-Ohesney Oopper Mine are, speaking generally, lenticular deposits of evidently more or less complete metasomatic replacements of the country rock along a line of powerful faulting. These lenses vary from 150 ft. to 400 ft. in length, and from 20 ft. to 100 ft. in width.

Jan 1, 1919

"Air Products approached LAC Minerals in 1987 to initiate trials with pure oxygen in the leach circuit at several LAC facilities in Canada. This paper gives an overview of oxygen use and covers specific operating data from the Doyon and Terrains Aurifères mills near Val D'Or in northwestern Quebec. LAC also uses oxygen at the Macassa mill in Kirkland Lake, Ontario.In addition to the LAC facilities, oxygen is currently in use for test purposes at the Holt McDermott mine in Kirkland Lake, Ontario and the Camflo mine near Val D'Or.There are two requirements for oxygen in the cyanide leach mill. Firstly, oxygen is required in the familiar gold dissolution reaction as follows:(1) 4 AU (s) + 8 NaCN (aq) + 02 (aq)+ 2H 20(aq) - 4NaAu(CN) 2(aq)+ 4Na OH(aq)Of the reagents on the left side of the equation, the availability of gold is fixed by the ore in question. Obviously, water is available in excess, 1eaving cyanide and oxygen as the limiting constituents in the process. Most mills operate with an excess of cyanide, which is fairly closely monitored. Dissolved oxygen levels, however, are not normally watched very closely and find their own level based on the temperature, the availability of compressed air and the ability of the ore to consume oxygen.Typical D.O. levels are in the 3-8 ppm range, however levels less than 1 ppm are not uncommon for refractory ores.With pure oxygen, dissolved oxygen levels as high as 30 ppm can be achieved. (Figure #1). This greatly accelerates the kinetics of the leach reaction and may also shift the reaction further towards completion thus increasing gold dissolution slightly."

Jan 1, 1990

By R. G. Kidel, S. C. Doming

The project has shown that it is feasible for a junior company to reopen a narrow vein-style gold mine and successfully take it into production. An intimate understanding of the mineralisation and a flexible approach to mining are crucial, as are stringent cost control and efforts to keep overheads low. The project has confirmed the geological complexity of the Main Lodes, which consist of highly sheared quartz-sulphide infill in strongly sericitised granodiorite. The existence of discrete high-grade zones within the Hangingwall Lodes has also been confirmed. Broad low-grade zones continue to be recognised and require the local application of bulk longhole mining methods. The initial mine plan called for predominantly longhole stoping, but adverse ground conditions have meant that a switch to air-leg mining has produced higher run-of-mine grades. The excess capacity at the processing plant can best be used by batch processing, with its reduced maintenance requirements

Jun 21, 1905

By S. J. Schatzel

Longwall coal mine operators in the US are required to ventilate multi-panel longwall districts but may have little or no knowledge about what happens to the ventilation air between the inlet evaluation points (IEPs), bleeder evaluation points (BEPs), and bleeder fans. The effectiveness of bleeder performance can directly influence the ability of a ventilation system to remove and dilute coal bed methane emissions. Consequently, the performance of coal mine bleeders is an important aspect of underground worker safety. U.S. coal mining stakeholders have acknowledged their belief that the T- junction split at the longwall face tailgate corner is very important in controlling the distribution of ventilation air. The percentage of air directed inby towards the bleeders and bleeder fan and outby to the submains is often not well-defined and can vary over the life of a longwall panel. To obtain direct measurements of bleeder performance, a tracer gas, sulfur hexafluoride (SF6), was released into the intake air stream along the panline of active longwall panels and in the bleeder/gob ventilation air inlets of an inactive panel. Tracer gas sampling was conducted underground using tube bundles attached to permissible vacuum pumps in the gateroads, former gateroads, and bleeders. Surface tracer gas monitoring was also conducted from operating gob boreholes and from bleeder fans. Testing was performed on multiple longwall panels which included various phases of longwall development and variable path lengths of ventilation air transport to bleeder fan installations. The applied methodology defines and describes coal bed gas pathways, rates, and volumes of movement at the bleeder/gob interfaces, and indicates flow rates for air/gas mixtures within these gobs. These findings are reported for three stages of longwall extraction using direct field-based measurements. Changes in the T-junction ventilation air distribution over the life of a longwall panel and its variable effect on panel ventilation airflow are discussed. These findings will assess the effectiveness of commonly applied ventilation strategies for improving air distribution and ventilation controls to meet statutory requirements and to achieve the desired ventilation patterns through multiple phases of longwall panel extraction.

Jan 1, 2011

By J. D. Steenkamp, G. E. Williams

Keywords: Ilmenite, titania slag, pig iron, rutile, zircon Located on the eastern shores of South Africa, 180 km north of Durban, Richards Bay Minerals (RBM) produces approximately 2.0 million metric tonnes of product annually making RBM a leading producer of titania slag, high purity pig iron, rutile and zircon. Heavy minerals are extracted from the nearby dunes by dredging and concentration on a floating gravity separation plant, followed by separation of the ilmenite, rutile and zircon at the mineral separation plant located at the smelter site. The ilmenite is processed through an oxidizing roast followed by magnetic separation and is then partially reduced to an 85 per cent TiO2 slag in one of four six-in-line a.c. electric arc furnaces. The slag is milled and then classified into two product sizes suitable as a raw material for both the sulphate and chloride pigment processes. The high quality iron produced during the reduction process is further processed to produce various grades of low-manganese iron. Around 95 per cent of the products are exported, yielding a world market share of about 25 per cent of titania slag, rutile, high quality pig iron, and zircon.

Jan 1, 2006

By Bibby P. A, Leupen R. A

A 24,300 tonnes per year state of the art Silicon smelter is being constructed for Barrack Silicon Pty Ltd at Kemerton, 20 kilometres north of the City of Bunbury in Western Australia. The plant is designed for the reduction of high purity quartzite lump to metallic silicon in two 27MVa Demag submerged arc electric furnaces. The primary reductant, a high purity charcoal, will be manufactured at the plant from locally sourced jarrah wood waste (Eucalyptus Marginata). Commercial silicon production is scheduled to commence in October 1989. Keywords: Silicon, Smelter, Quartzite, Furnace, Charcoal, Jarrah, Wood, Eucalyptus Marginata.

Jan 1, 1989

By D. F. Malan, Y. Jooste

"SynopsisScattered mining was practised on Kusasalethu Mine (previously Elandsrand Gold Mine) prior to 1998, but at deeper mining levels it was no longer feasible, since it would have resulted in unacceptably high stress levels and energy release rates. Longwall mining was not adopted at these depths as the mine required a more flexible mining method owing to the highly variable grade and the presence of geological structures. A mining method was developed that consisted of dip stabilizing pillars for regional support, as well as bracket pillars to clamp geological structures. A strict sequence of extraction was followed and this, together with the particular layout, was called the ‘sequential grid mining method’. This method addressed two key problems, namely negotiating adverse geology and the erratic grade of the Ventersdorp Contact Reef (VCR) orebody. However, a significant drop in production rates resulted in the need for alternatives and improvements to the original mine design. Modifications to the design were proposed in order to increase production rates, and an investigation to consider the rock engineering implications of these modifications was conducted. The study indicated that the modified method, called the ‘multi-raise mining method’, appears to be feasible and might address some of the production problems that were experienced with the original sequential grid design. An analysis of actual seismic data showed no significant differences between the original sequential grid mining and the implemented multi-raise mining. The numerical modelling of the mining layouts showed slightly higher interim energy release rates (ERRs) and average pillar stress (APS) levels during the extraction process. The final values are nevertheless identical to that of the original sequence. The study also investigated the use of a modelled moment method to analyse future seismic trends. The study illustrated that the expected seismic trends will be very similar for the multi-raise method compared to the original sequential grid mining method. This study is nevertheless considered of a preliminary nature and ongoing monitoring and analysis of seismic data at the mine is required to verify the response of the rock mass to the modified sequence and increased extraction rate. In particular, future work needs to investigate the effect of mining rate (advance rates in individual panels as well as volume of mining in particular raise lines) on the level of seismicity."

Jan 1, 2015

The Subtropolis mine is a room-and-pillar mine extracting the Vanport Limestone near Petersburg, Ohio. In February 2018, mine management began implementing a heading reorientation to better control the negative effects of excessive levels of horizontal stress. The conditions in the headings improved, but as expected, stressrelated damage concentrated within crosscuts. The mine operator has worked to lessen the impact of the instabilities in the outby crosscuts by implementing several engineering controls. With the implementation of each control, conditions were monitored and analyzed using observational and measurement techniques including three-dimensional (3-D) LiDAR surveys.

Jan 7, 2020

By G. Ahnell

Throughout portions of four (4) heavily mined Appalachian states subdivided by the Mine Safety and Health Administration (MSHA) as: District 3 -Northern West Virginia and Maryland; District'" -Southern West Virginia; District 5 -Virginia; and District 6 -Eastern Kentucky, active coal mine waste embankments associated with mechanical and/or chemical coal processing facilities of various levels of coal preparation were inventoried. For each site plant specifications, disposal techniques, embankments' characteristics, and coal source data were accumulated. Mapping at 1: 24, 000 and 1: 250,000 scale and Disposal Site Characterization forms were developed to present the findings. Associated abandoned surface and underground openings near each site were also indicated as well as locational data for each site and the areas environmental conditions - temperature, precipitation and vegetation types. A state-of-the-art review of coal preparation, waste disposal, and alternative uses of coal waste is also included.

Jan 1, 1982

By Debbie Laney

DOUG HALBE: Second in our quick run-through on "Operating Ideas That Have Saved Me Some Bucks," was Debbie Laney of Rayrock Mines. Debbie apologizes. She can't be here. But she said, "Doug, don't worry. I've asked Mary Korpi to present the paper. We're both short, blond, and wear glasses. Nobody will know." [laughter] Mary, I caught it right away. You ladies can't fool us. Debbie, who wrote the paper, has spent almost her entire career in operations. She is currently metallurgical manager of Rayrock Mines in Valmy, Nevada. Mary Korpi is also a real operator (that doesn't sound right). She has been responsible for a number of operating areas at Newmont's Nevada operations, and she is currently taking a break from operations as manager of public relations/employee communications for Newmont Gold in Carlin. MARY KORPI: They told us this year at Newmont that we were going to have to work twice as hard. I had no idea it meant I would have to work for another company, too. Over the years, and many times in association with work for mid- to small-size mining companies, there have been two areas that seem to have been the focus of cost savings when looking at new facilities or new processes.

Jan 1, 1998

By W. J. Spat

Political risk is an integral part of the mining business in Northern Andean countries. Peru, Ecuador, Colombia, and Venezuela all have a higher than average political risk compared with other South American countries. Successful operations in such contexts require: 1. Good political risk information; 2. A thoroughgoing political risk management plan; and 3. A strategy to deal with political risk perception on the part of the investing public. Obtaining quality political risk information, developing a political risk management plan, and addressing political risk perception are the foci of this work.

Jan 1, 1999