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By M. J. Sapko

The design requirements for mine ventilation seals have undergone a radical transformation in recent years, and these revisions have greatly increased the cost of the seal designs and their construction. For example, in the past two years, new federal regulations have increased the minimum design requirement to withstand explosion pressures from 138 kPa (20 psig) to 345 kPa (50 psig) or 827 kPa (120 psig), depending on whether the sealed mine volume is monitored continuously or not. Moreover, there is still a possibility that under certain conditions (such as detonations) even higher pressure requirements may be necessary. The ability of a monolithic, stand-alone mine seal to reliably withstand the full range of current and future pressures is becoming increasingly difficult and expensive. In an effort to develop a practical alternative, the West Virginia Office of Miners? Health Safety and Training (WVOMHST) and the National Institute for Occupational Safety and Health (NIOSH) have collaborated in a research effort to develop a practical, economic, and safe mine sealing technique that can enable mines seals to meet the full range of new explosion pressure design requirements. The basic idea is to use a barrier of common mine gob and rubble in combination with a conventional mine seal so that the pressure resulting from a gas explosion is reflected, absorbed, and attenuated, so the pressure on the ventilation seal is reduced. This paper discusses some concepts and preliminary test results for a ?Passive Mine Blast Attenuator? (PMBA) that can provide a useful alternative to increasingly larger and stronger stand-alone mine seals. Numerical models and full-scale experiments conducted at the NIOSH Lake Lynn Laboratory Experimental Mine (LLEM) show that the use of a PMBA can signficantly reduce the blast pressure and impulse on conventional ventilation seals. DISCLAIMER: This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by the National Institute for Occupational Safety and Health (NIOSH). It does not represent and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Hindmarsh J. W, McCoy A. E R

Instantaneous outbursts of coal and gas have occurred at various times in several working districts of Metropolitan Colliery, N.S.W.They have occurred in headings only, under both hand and mechanised conditions, and with seam gas ranging from mainly methane to nearly pure carbon dioxide. A modification of inducer shotfiring using a shear cut was introduced in 1955, and in 1961 full face firing both to a machine cut shear and off the solid was introduced. The current series of outbursts -1961 to 1963 - has been induced under these systems with full control of the time of outburst, but without prediction, and with some disappointing production features.Various aspects of current conditions and practices at Metropolitan are considered singular, such as the coarse granulometry of outburst coal, the prevalence of floor heave, the absence of strong structures at outburst sites, the possibility of outburst at any stage in pillar formation up to the last few yards, the effect of rate of advance on outburst occurrence, and the mildness of many outbursts experienced.It is concluded that inducer shotfiring is a reliable control but it suffers by comparison with outburst-free conditions, and that control by preyention would be preferable.INTRODUCTIONThe phenomenon of instantaneous outbursts of coal and gas has been described in detail previously (Hargraves, 1958). Briefly, it is a combined gas and stress hazard of deep coal mining, usually occurring in virgin work and during active face advance, when coal and seam gas burst from the face into the workings.Instantaneous outbursts have occurred sporadically at Metropolitan Colliery, N.S.W., since 1895. Early outbursts were recorded as firedamp and recent outbursts are of blackdamp.Mining methods used have been conventional hand work, with progressive and relatively complete mechanisation over the past 25 years to substantially conventional...

Jan 1, 1964

By B Mobilio, M Secheny, J Rachocki, G B. Sharrock, A Jäger, J L. Lett, I Brunton, G W. Capes

Establishment of the Cadia East Panel Cave Stage One (PC1S1) commenced with the firing of the first bell in early 2011. Production began with the completion of the undercut in May 2014. PC1S1 used a post-undercut composed of 114 drawbells covering a footprint area of 73 438 m². The extraction level is located at a depth of 1200 m below the surface and is based on a 32 × 20 m El Teniente layout. Cave establishment required the construction of multiple conveyor drifts, a large-capacity jaw-gyratory crusher and ancillary ventilation and pumping infrastructure. Preconditioning via hydraulic fracturing and blasting was implemented at various locations of the cave block height. This paper presents an overview of the key learnings from the commencement of undercutting to surface breakthrough, including rock mass classification and modelling, stress measurements, preconditioning, numerical modelling and cave monitoring.CITATION:Lett, J L, Brunton, I, Capes, G W, Jäger, A, Mobilio, B, Rachocki, J, Sharrock, G B and Secheny, M, 2016. Undercutting to surface breakthrough – Cadia East panel cave (stage 1), in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 65–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

In coal mining, geophysical techniques have an established application in determining the location of seam boundaries ahead of the face so that underground mines can be planned to avoid any geological structures that might disrupt production. Geophysics can also be used in geotechnical studies to determine the in situ properties of the rock mass and the response of the rock mass to the mining. The use of geophysical logs and microseismic monitoring in these geotechnical applications are discussed in this paper.

Jan 1, 2002

Sustainable development is a critical discussion topic in the mining industry today. The topic is necessarily broad and complex, covering an entire spectrum of related areas, from geology to end-use products. The objective of this keynote address is to focus on the chemicals and chemistry aspects - especially research and technology transfer - in sustainable mineral processing. Chemicals came to play a critical role in mineral processing during the last century, and they will play an equally vital role in confronting the sustainability challenges of the 21st century, particularly in the areas of greener chemicals, water efficiency and water resource management; waste reduction and remediation; minimising environmental impact, safety and health risks (meeting and exceeding the requirements of regulations); energy efficiency; and converting mineral resources into reserves. This keynote address argues that the current research framework is no longer adequate to serve the goals of sustainable mineral processing. The problems studied are often too narrowly defined or irrelevant, while the research efforts are fragmented and the methods and approach employed are often too reductionistic to produce useful knowledge. A new framework for research is needed. This address further argues that a new framework based on a holistic or systems approach can best tackle the challenges of sustainable mineral processing. Central tenets of this approach include a recognition that, in complex systems, the behaviour of the whole system is more than the sum of the individual contributions, and that interactions occur in real time, often in subtle and complex ways. The focus is thus on the behaviour of the whole system. Indeed, a comprehensive understanding of the system through large-scale measurements should precede a study of parts or of idealised models of the complex system. The result will be a sound knowledgebase, better solutions to the challenges of sustainable development, and improved technology transfer. Developing such a framework will pose a formidable challenge, requiring significant time and effort as well as a confluence of diverse specialties and strategic collaboration. Fortunately, recent developments in the context of reagent optimisation provide us with a prototype of a holistic approach. We can also draw upon methodological innovations in the biological sciences, where the critical need for a systems approach is well recognised and significant advances have been made.

Sep 13, 2010

By B. K. Belle

The use of diesel engine locomotives in South African mines can be traced to Van Dyk Consolidated Mines Ltd on the Witwatersrand gold mines in 1928 as a replacement for battery locomotives. The advantages and disadvantages were recognized in those days, and surprisingly, there are no significant additions to this list, but only refinements. In the absence of any Occupational Exposure Limit (OEL) for Diesel Particulate Matter (DPM) in SA, the Mine Safety and Health Administration (USA) rule is currently being used as a benchmark for the ventilation engineering designs. This paper discusses the ongoing SA journey of measurement and limitations of exposure data for ventilation planning and regulatory purposes. The currently accepted DPM limits are based upon the belief that they are economically and technically feasible for the mines to reach and are not necessarily health based. For SA underground platinum mines, a median TC/EC ratio of 1.8 with a range of 1.2 to 5.8 was observed. For SA coal mines, a median TC/EC ratio of 1.44 with a range of 1.25 to 2.13 was observed. While it is common practice in the USA to use the ratio of TC/EC for metal mines to be 1.3, the ratio found in local platinum mines is 2.2 and for coal mines, the ratio was 1.53 which is lower than Australian studies, i.e., 1.96. It has been shown that a need for critical analysis of TC/EC ratios exists, and possible reasons for variance must be understood before stringent adoption of overseas recommended limits for DPM. It is hoped that the findings from this paper would provide input to scientific approaches in developing appropriate conversion factors, limits for DPM and also in ensuring appropriate error factors (currently 1.14 for TC and 1.2 for EC) for compliance determination.

Jan 1, 2009

By I. Tsolas

This paper presents the use of non-parametric approach (i.e., data envelopment analysis, DEA) for the development of environmental sustainability indicators in mineral processing using environmental, economic and/or integrated indicators (i.e., indicators that interrelate two dimensions of sustainability). A case study based on real publicly available data is presented to illustrate how the proposed approach can be implemented in practice. The merit of this approach, which is based on the productive efficiency framework, is that it provides environmental sustainability indicators that can be used internally for benchmarking purposes and externally for sustainability reporting.

Jan 1, 2008

By Joner Oliveira Alves

The aim of this work was to study the use of steelmaking slag as raw material to the production of rock wool and glass wool. Firstly, the chemical composition of the slag was analyzed. These results were used to infer the amount of additives to assemble the charge for the experiments. A laboratory-scale electric furnace was used to melt the mixtures used as charge. The melt material were turned into a water filled recipient, this process was performed in order to impose a fast freezing that is a characteristic of mineral wool production. Finally, with the rest of the melt material it was performed the Herty Viscosity Test. Samples of the produced material were characterized by different analyses. The results found in this research may lead to a technological innovation, because they indicate that the use of steelmaking slag to produce rock wool and glass wool is possible.

Jan 1, 2009

Work undertaken in the field of cut-off grade optimization has not advanced much beyond the work undertaken by Lane in 1988. His definitive work is based on the calculus of the Net Present Value criterion which is the most widely understood, consistent, and appropriate method by which sequential cash flows arising from the extraction of mineral reserves from an exhaustible resource can be represented. Although the mathematics is not complex Lane’s method is not a widely appreciated or applied approach to maximizing the value of a mining operation through selection and balancing of operational cut-off grades. Three stages in a mining operation namely, mining, processing and marketing were defined by Lane and the economics of each stage are identified and isolated to provide an optimum cut-off for each stage. Points of intersection along the present value curves for each stage of a mining operation are used to identify balancing cut-off grades at points where the capacity of the mining, processing and marketing stages is fully utilized and the Net Present Value of the operation is optimized. Data that simulate a small, deep-level Witwatersrand-type gold mine with an average grade of 6 g/t Au and a logrithmic variance of 1.2,are applied to the model to illustrate the benefits of representing cut-off grades in terms of present value curves for different segments of a mining operation. Keywords: Cut-off grade, Net Present Value, grade-tonnage curve, balancing cut-off grade, mining, processing, marketing.

Jan 1, 2003

By Frederic M. Langevin

?? Introduction ?? LaRonde ?? History of Seismicity and Rockbursting ?? November 27th 2002 Rockburst ?? April 1st 2006 Rockburst ?? December 11th 2006 & January 11th 2007 Rockbursts ?? Seismic Risk Management Plan ?? Conclusions ?? Located in Northwestern Quebec (Can.) ?? In operation since 1988 ?? Reserves at Shafts #1 and #2 depleted ?? Production now comes entirely from Penna Shaft ?? Deepest single-lift shaft in the western hemisphere (2240 metres) ?? 7300+ tonnes per day ?? 2007 Reserves (proven & probable): ?? By-products: Ag, Cu, Zn ?? Sinking #4 Shaft (LaRonde II winze)

Feb 1, 2008

By McHenry Mosier

The Bureau of Mines, United States Department of the Interior, has established a testing adit on the Government reservation at Mount Weather, Virginia, to facilitate research on the fundamentals of mining under actual metal-mining conditions. A number of sites in several Eastern States were investigated, but Mount Weather was selected because the rock seemed best suited for rock drilling and other mining tests and because the ground was already owned by the Federal Government, the site having been acquired in 1902 for use of the Weather Bureau. The testing adit has an advantage over an active metal mine for certain investigations because variable conditions affecting any particular research problem can be controlled and maintained in a fixed status, whereas in an operating mine this seldom is feasible. Operations were begin in September 1936, with a crew of four laborers under a resident engineer. The laborers were recruited from nearby farms, and although they had no previous mining experience, they have developed into satisfactory miners.

Jan 1, 1939

By S. J. Benson

The Harts Range deposit, owned by Olympia Resources is located some 130 kms northeast of Alice Springs, in central Australia (part of Australia’s Northern Territory). The core economic minerals here are industrial grade garnet and alumino magnesio hornblende (AMH). The resource contains an estimated 2.3 million tonnes of recoverable garnet and 6.2 million tonnes of recoverable AMH, making Harts Range one of the most significant abrasive medium deposits in the world. Part of the general marketing axiom of Olympia Resources is to make high quality products from the garnet and also a special series of blended garnet/AMH products to match the needs for other sectors of industry. The deposit mineralization is of alluvial origin and thus, requires no significant liberation regimes. Over 50% of the head feed is in the form of SiO2/quartz and as much as 17% is –63micron clay slimes and mica. Original pilot scale testwork for flowsheet development centred around fairly conventional wet gravity systems, with spiral concentrators being the pre-eminent separating device. To a point, this type of flowsheet was going to achieve some of the aims albeit fairly predictably. The one area that this circuit would be very limited though is in the recovery of the very coarsest of the medium SG minerals. This was going to be a very important and longer-term costly flaw. Amongst the highest demand, greatest value of products to be produced will be the range of garnet & AMH in the +600 microns sector. A flowsheet dominated by spirals would be fated to forfeit a significant proportion of these coarse minerals to tails. At the Outokumpu Technology P/L test facilities in Perth, testwork was conducted using a pilot scale Floatex® Density Separator, the LPF-230 model. Using a twin stage approach, whereby a primary Floatex® underflow reports directly to a secondary Floatex®, recovery of the economically important +600 micron garnet was increased from 65% in the spirals-only flowsheet to 95% using the Floatex® based flowsheet. Finally, the other significant aspect of this approach is in substantial simplification of the circuit required and a huge reduction in plant footprint. Also, the nature of using hindered settling provides substantial opportunities for process control and automation.

Jan 1, 2005

THE solid nonmetallic inclusions that are present to some extent in all commercial steels have been variously designated. In early references they were usually called slag inclusions, and. this terminology is still retained to some extent. On the premise that all nonmetallic matter produced in a metallurgical process is slag, this can be justified. We have come to think of slag, however, in a more restricted sense, and calling these particles slag inclusions is further objectionable because it fosters the erroneous concept that they are actually incorporated portions of furnace slag. Rarely is this true. The term sonims (coined from solid nonmetallic impurities) was proposed many years ago but never came into common use. In general the term "nonmetallic inclusions" seems to be satisfactory and adequate. NATURE AND CONSTITUTION OF NONMETALLIC INCLUSIONS From the standpoint of origin, inclusions fall naturally into two classes: (1) those that occur as a result of reactions taking place in the body of the molten or solidifying metal and (2) those that result from the mechanical incorporation of refractories or other materials with which the steel comes in contact. The former are by far the more numerous and have been called indigenous, natural, or native inclusions. The latter are by their very nature sporadic in occurrence and have been called exogenous, accidental, adventitious, or foreign inclusions. They are often referred to as the "slag stringer" type, though here also the material is not likely to be furnace slag. Substances Found in Inclusions. Nonmetallic inclusions are composed principally of oxides and sulphidea but carbides and nitrides sometimes play an important role. In the case of indigenous inclusions the reactions by which these particles are precipitated from the molten or solidifying steel may be caused by (1) oxidation such as may occur during refining or during tapping and teeming, (2) deoxidation by added alloys, (3) change in equilibrium constants as the steel cools to the freezing temperature, (4) decreased solubility with lower

Jan 1, 1944

By Brigitte J. Dejou

The Red Dog sediment-hosted zinc-lead deposit is located in the Brooks Range thrust belt in northwest Alaska, approximately 1000 km northwest of Anchorage. The mine constitutes the primary deposit in a 400 square kilometre district, which hosts several other mineral occurrences. All the known mineralisation is hosted by the Mississippian Ikalukrok Member, deep basinal shale of the Kuna Formation, part of a Devonian to Cretaceous sedimentary sequence. The rocks underwent intense deformation during the Brookian Orogeny in Middle Cretaceous time. Several thrust faults juxtapose the stratigraphy. The Red Dog mine is composed of four deposits which together contain 105 Mt in resources and reserves for a total resource exceeding 18 Mt of Zn metal. The mine is an open pit with 25 foot high benches. The biggest challenge is not the Arctic conditions, but metal extraction, due to the fine grained nature of the mineralisation and the variability of the ore. The mine produces Zn and Pb-Ag concentrates that are shipped to smelters around the world from the Red Dog port facilities during the short summer period. Ore mineralogy is generally simple and consists of sphalerite, pyrite, galena and marcasite. The deposits are generally overlain by decametre thick exhalative barite horizons and exhibit strong silicification, which locally obliterates the original textures. Although described as a world class Sedex-type deposit, a large portion of the mineralisation exhibits sub-surface replacement textures. Moreover, unlike most other Sedex deposits, the reconstruction of the basin is made difficult by the structural complexity of the district. To assist exploration in the district, several assumptions are made regarding the deposit settings relative to metal source, growth faults or crustal extension.

May 1, 2006

By S Hapugoda, A Poliakov, E Donskoi, L Lu

A significant amount of metallic iron in the world is produced in blast furnaces from iron ore pellets. To control the quality of pellets and to optimise pellet production, characterisation of both green and fired pellets is required. Optical image analysis (OIA) allows identification of different minerals, binder, remaining fluxes and porosity within pellets.For proper identification of the mineralogy, porosity and texture in pellets a high magnification is required, therefore each individual image covers only a very small portion of the pellet. At the same time the characterisation of pellets requires that the whole pellet is represented as a single object, so the size of the resulting overall image at high magnification can make it difficult to handle. A solution to this problem has been implemented within the CSIRO OIA package Mineral4 by combining images at different levels. Namely, to average out local irregularities, individual frames can be stitched during imaging into larger MosaiX images. Mineral4 further combines these MosaiX images into a single panorama image of the whole pellet.The proposed procedures allow the calculation of mineral and porosity spatial distributions, local gradients and abundance graphs based on the distance from the centre of the pellet. The ‘Pellets’ module of CSIRO OIA software also allows for characterisation of large irregularly shaped particles of lump ore and sinter.CITATION:Poliakov, A, Donskoi, E, Hapugoda, S and Lu, L, 2017. Optical image analysis of iron ore pellets and lumps using CSIRO software Mineral/Recognition, in Proceedings Iron Ore 2017, pp 583–592 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By S. P. Ball, A. J. Monhemius

In a laboratory study under acidic oxidising conditions, the thiocyanate system gave results at least as good as cyanide and considerably better than thiourea, with modest consumption of SCN (less than 1 kg/t ore). For both cyanide and thiocyanate lixiviants a residence time of about 24 h was required for maximum gold extraction, which was generally in the range of 92-96%. The adsorption of gold from thiocyanate leach liquors was found to be rapid, but activated carbon catalyses the autoreduction of ferric iron to ferrous iron in thiocyanate solutions, suggesting that ion exchange may be a better recovery route

Dec 1, 1995

Conventional waste management practices produce two waste streams for the construction of separate disposal facilities. The design of tailings impoundments is usually controlled by physical stability. Waste rock materials offer high shear strength characteristics for waste dump construction, however the hydraulic properties promote oxidation. The problem of oxidation is significantly reduced for tailings due to a fine texture that augments water saturation. Co-mixing of tailings and waste rock involves the intimate blending of tailings and waste rock to create a new material with superior physical and hydraulic properties. The new material has a low hydraulic conductivity, low compressibility, high water retention capacity and high shear strength. Co-mixed tailings and waste rock restrict oxygen entry and water seepage to minimize acid generation and metal leaching. Co-mixed tailings and waste rock may be used to construct cover systems, internal barriers and seals, confinement structures and full depth waste repository. The results of a laboratory program to characterize the physical and hydraulic properties of Comix tailings and waste rock are presented here. Various ratios of tailings were blended with three distinct waste rock materials. The saturated hydraulic conductivity for the Co-mixed materials was found to vary between 2 x 10-7 m/s and 5 x 10-8 m/s depending on blend ratio, waste rock type and compaction. This paper introduces concepts for the co-disposal of tailings with waste rock and evaluates the hydraulic behaviour of a Co-Mix waste system. The potential benefits of Co-Mix are shown for a typical mine.

Nov 1, 2002

By Thom Seal, S. J. Jung

This paper will combine three SME annual meeting presentations on reducing gold inventory in cyanide heap leaching. Information on Part I – Side slope leaching (SME 2003), Part II – Determining the dry zones using geophysical resistivity (SME 2004), and Part III - Presents a new technology “Hydro-Jex”, to introduce the required lixiviants to the un-leach or under-leach zones in heaps (SME 2005). This paper will describe how Newmont Mining Corporation continues to improve the economics of the heap leaching process for precious metals recovery.

Jan 1, 2005

By R. Patel, D. R. Taylor, P. M. Varley

In-situ measurements of ground stress were made from surface boreholes, using overcoring and hydrofracturing techniques, to obtain data for the detailed design of the underground works at Pergau. Unexpectedly low stresses were measured and appeared to correlate with apparent hydrofracturing observed during permeability testing. The low values of the minor principal stress had a major impact on design, particularly of the lining for the pressure tunnel and shaft. Additional hydrofracture tests were made underground during construction of the low- and high-pressure headrace tunnels and the pressure shaft, to define the vertical reduction in the minor principal stress with overburden. These data were then used to locate and design the steel and reinforced concrete linings

Jun 19, 1905

By Paul Hughes

This paper summarizes current underhand paste backfill mining as applied to Goldcorp Inc?s Red Lake Mine, Newcrest Mining Ltd?s Kencana Mine and the Lanfranchi Nickel Mine as well as ongoing research at the University of British Columbia?s Norman B. Keevil Institute of Mining Engineering. The Red Lake Mine utilises a 6 m wide undercut with a 2 MPa unconfined strength paste in order to selectively mine its high grade, high-stress orebody. Kencana?s orebody is located in a poor rock mass environment. An 8 m wide, 2 MPa unconfined strength paste sill allows a safe working condition for its high grade orebody. The Lanfranchi Nickel Mine utilises a cable-supported, 2 MPa paste, with 12 m span sills, to optimize the mining of the squeezing rock mass. This paper details the rock mechanic hazards, ground support techniques, paste practices and unique conditions for each mine. Further, an update of ongoing research at the University of British Columbia, focussing on the optimization of safe mining in underhand cut-and-fill mining in high-stress/weak rock masses, is presented.

May 1, 2011