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The cost of power is an important matter to mining companies generally and this thought that the members of the Australasian Institute of Mining Engineers, as well as the engineering and mining professions generally would be interested in any proposal for the reduction of that cost-has led to the presentation of this paper.The writer trusts that the description will be found clear and increase the interest in this exceedingly interesting subject. In the working up of the electrical arrangements touched on in this paper, the author has had the able assistance of hisfriend Mr. F. J. Mars, to whom he offers his hearty thanks. The selection of the best class of power plant for a mine is a very difficult and large problem and it is quite out of place to dogmatise that anyone of the many systems that offer isbetter than another, eg that the all electrical is better than the partly direct steam-driven and partly electrical, or that a gas plant is better than a steam plant.Such a selection is one that calls for very careful and close consideration, in each particular case, of a large number of regulating factors before it is possible to arrive at a proper decision.

Jan 1, 1911

By Esaki M, Nishimura K

This paper describes the results of the field application tests at Miike Colliery on the integrated automatization of the longwall mining system for medium thick coal seam. The purpose of the research is to develop an automatic longwall mining system which can be controlled accurately from outside of the face, and the ultimate goal is an eliminate of men from the face. Presently, the field test is being conducted in Yotsuyama mine following to a success in the performance test on surface. Remote Batch Control System for shield supports has been adapted to operate all supports from the control panel located at the entrance of the face. Remote monitoring and control system of the drum shearer has also been tested. The system makes it possible to operate the shearer either at the main gate or full automatic. Productivity and safety will be substantially improved as those systems enable to eliminate all workers from the face under the severe working conditions with high ground pressure and hot and humid atmosphere due to increasing mining depth. So far, we have been satisfied with the results of the field test and those system will be an effective countermeasure to operate the face with a high risk of rock-burst.

Jan 1, 1987

This study is to compare reinforcement of rebar and spiral bolts using laboratory pull-out test. For this purpose, the pull-out test was performed in laboratory for a curing period of 7- and 28-days. Based on the results of the laboratory pull-out test, the pull-out load of two support members rapidly increased with displacement until the breakpoint and then gently increased with displacement. The maximum pull-out load of spiral bolt was larger than that of rebar bolt. This implies that a spiral bolt is more stable than a rebar bolt for securing the stability of a ground or rock mass when a support was installed in a ground or rock mass under the same condition. In addition, the maximum external pressure of two support members increased with pull-out load and with displacement and the distribution of external pressure was commonly larger at the upper part than at the lower part of specimen. This indicates that the bond failure location by pull-out load should be mainly occurred at the surface portion of specimen. In conclusion, the reinforcing effect of a support depends on a curing period and a type of support member, and reinforcement of a spiral bolt is more effective than that of a rebar bolt.

Dec 6, 2010

By Christie GB, Mainwaring DE, Leong YK

High solids brown coal slurries have been prepared with concentrations approaching those achieved with bituminous black coals. The high inherent water content and macroporosity of Victorian brown coals have been reduced in a controlled manner by chemical and mechanical means. The hydrophobicity of the coal surface has been increased sufficiently to reduce the tendency for swelling and water uptake. This together with densification has allowed the solids content to be progressively improved from 25% solids with raw coal to 65% solids with modified coals. Both raw brown coal and modified brown coal suspensions show shear thinning behaviour resulting in lower viscosities at higher flow rates. All coal suspensions displayed a yield stress once sufficient solids concentration was achieved. This yield stress can be used in the prevention of solids settling. Under simple shear mixing the network structure that provides the yield stress quickly breaks down to a low viscosity fluid with reduced yield stress and a pumpable consistency. The time necessary for structural recovery is in the order of days permitting shut-down and start-up of fuel delivery systems.

Jan 1, 1987

By S Hall

Mining schools around the world, many unfortunately now closed, were often established to teach the techniques of narrow vein mining and associated processing to students studying part-time while working in the industry. This arrangement ensured graduates (or æassociatesÆ) had a mix of skills and knowledge invaluable to the industry.It is argued that there is still a need to educate students in these narrow vein techniques and that there will be a growing demand for such graduates with a high level appreciation of this type of mining. There is also a need for innovation in narrow vein mining and processing to develop specific technologies and allow the use of techniques applied in æbulk miningÆ to achieve improvements in productivity, safety and economic performance.This paper aims to review the situation with regard to education and innovation in narrow vein mining.CITATION:Hall, S, 2012. Narrow vein education - back to the future?, in Proceedings Narrow Vein Mining 2012 , pp 23-26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Sans H

The geostatistical Discrete Gaussian (DG) model is demonstrated to be capable of providing an effective means of implementing change of support for Enterprise-style mineralisation and thus providing reliable global recoverable resource estimates. At Enterprise, sample grade distribution proves to be highly positively skewed, therefore significant deskewing of the histogram and reduction of variance occurs when going from sample to block support. The DG model was experimentally tested in'the Southern Primary Zone (SPZ) at Enterprise, where high anisotropy ratios and pronounced short range structures are observed in variograms. The experimental test was run for a change of support for which the variance reduction was. approximately 60 per cent. This reduction is similar to that predicted by Krige's Relationship ('the volume-variance relationship') for the practical situation of a change of support from 5 m vertical blasthole samples to 3 m x 8 m x 5 m selective mining unit (SMU) blocks. The DG model was found to correctly predict the grade tonnage relationships for a wide range of cut off grades. The experimental test indicated that, given a representative histogram and variogram, the DG change of support provides a computationally efficient and practical means of reliably assessing global mineable resources at the early stages of a mining project. Further, it allows a range of selectivity strategies to be meaningfully and comparatively considered prior to mining.

Jan 1, 1995

By Siwiec A

The laboratory investigations which are necessary to evaluate the mineral processing effectiveness usually include density separation of narrow size fraction of the feed and one of the products. In each size - density fractions the content of valuable mineral has to be determined. These data and yield in each size - density fraction can be specified by a matrix of partition coefficients. They are counterparts of recoveries. These coefficients can be compared with the mean recoveries at each density or size fraction or the total recovery, to determine which density - size fractions are processed in the best or worst way. The basic categories are: vector of metal content l _i 1711, 7t2, òòò, ltM I ò vector of particle size distribution x = I d1, d2, ..., dN I ò matrix of partition coefficients P11, P12, Pi N P _ P21, P22, ..., P2 N PM1 PM2..., PMN These three conceptions allow one to determine all the basic metallurgical parameters of a mineral processing unit. Losses of valuable mineral are connected with: ò mineralogical composition of the ore (types of minerals, their properties, dissemination, crystallochemical affinity, type and properties of gangue minerals), ò applied technology and technical equipment (beneficiation as a stochastic process, processing methods, process control, intergrowth liberation, water quality). Examples of application of the analytical method proposed are given for zinc - lead and coal processing plants.

Jan 1, 1993

By M K. C Roberts, M G. Magwaza, J W. L Hanekom, P Piper, R Lousteau

Due to the perceived potential to extract the second economic manganese seam at its Black Rock Operations in the Northern Cape Province, South Africa, Assmang commissioned an investigation with respect to mining method and sequencing of the two orebodies in 2007. Based on this initial study into multiseam potential, conditions and impacts, the rock engineering aspect was expanded to determine conceptual rules to govern the extraction of both manganese seams using the normal bord-and-pillar layout implemented at this operation. This work included the theoretical analysis using basic pillar design practices and numerical modelling, including the use of Map3D, UDEC and Phase2 codes.In 2013, Assmang launched a large-scale investigation into the potential to increase mine output from all possible manganese sources at the operation. Included in this investigation was the requirement to confirm or modify the conceptual multiseam extraction rules to implementation. As part of this confirmation process, stress measurements, borehole camera audits and additional numerical modelling were performed at a particular site on the operation where a limited extraction of both seams had been undertaken. The results obtained from this process provided confidence in the conceptual extraction rules and allowed the derivation of final extraction rules that will be implemented at the operation as the multiseam mining process becomes more widespread.CITATION:Hanekom, J W L, Roberts, M K C, Magwaza, M G, Lousteau, R and Piper, P, 2014. Confirmation of multiseam extraction rules for Black Rock Manganese Operations, Assmang, Northern Cape, South Africa, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 107–116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

The mining of high-grade narrow vein deposits is a predominant field of activity in the precious metal sector. These types of deposits are located throughout the globe and have a significant presence in mining operations. The principle factor that has undermined the profitability and effectiveness of mining such ore zones is the substantial dilution that occurs when blasting with explosives during extraction. In order to minimise ore dilution, the thermal fragmentation mining method enables the operator to extract a narrow mineralised corridor, 30 cm to 1 m wide (according to the true width of the ore vein). By inserting a strong burner powered by diesel fuel and air into a pilot hole previously drilled directly into the vein, a thermal reaction occurs spalling the rock and enlarging the hole to 30 - 100 cm in diameter. This patented method produces highly concentrated ore, resulting in 400 - 500 per cent less dilution when compared to conventional mining methods. The mining method was conceived with the aim of mining ounces, not tonnes. This method of extraction, reduces the environmental impact of mining operations since much smaller quantities of rock are displaced, stockpiled, and treated using chemical agents. The fully mechanised equipment operated by a two-person team, maximises the effectiveness of skilled personnel, increases productivity, and reduces risks of injuries. Important economic benefits are generated for large- and small-scale mining operations alike. For large-scale operations, the mining method increases mining reserves, lowers the cost per ounce, and increases the total profitability of existing mine operations. The method also significantly lowers costs and risks of developing and mining small-scale deposits, requiring less investment capital, shortening the payback period, thus reducing the lending risk.  Combined with a small modular processing unit able to process between 100 - 300 tons per day, the method substantially lowers the financial break-even point for small-scale mining operations in a narrow vein environment. The company has been working with the technology at its Rocmec 1 mining site; results achieved and future developments are discussed.

Jan 1, 2008

Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts.This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise:1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions,2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and3. ways to improve the effect of methane predrainage.Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.

Jan 1, 1991

By H Jones

The paper outlines the adoption and evolution of ‘sustainable development’ as a concept in tailings management practices in the mining industry over the last 30 years. Over 500 lives have been lost in tailings facility accidents since World War 2. The paper outlines commonalities in many of these accidents, particularly the role of excess water. It considers the role effective tailings management can play in enhancing the social acceptability of mining in the future.Tailings management is a major operating cost at many mines while the cost of successfully closing tailings facilities is also very high. Current tailings management practices in the industry are outlined. The technical and engineering challenges of reducing potential risks associated with tailings by reducing water entrainment are described. The successful development of practical techniques to better manage tailings and reduce water consumption and wastage are described. For example, water removal in the alumina industry to produce a paste for dry stacking is now a reality.The future adoption of these new risk reducing techniques by the industry is discussed and the implications of the adoption or non-adoption of these techniques on the industry’s future ‘social licence’ is considered.

Nov 22, 2011

By C Harwood

Underground coal mines in the United States are in the process of completing installations for tracking and communication systems, mandated by Congress after a number of recent coal mine disasters. Yet, evaluation, modelling and testing of such systems has lagged due to legislated changes, abruptly introduced into the coal mining industry. System installation in a wide array of mine types, configurations, layouts and characteristics has provided a wealth of information regarding their potential in underground environments. Data collected from numerous installations for a variety of systems can be used to further define true capability and accuracy of communication and tracking packages. This paper describes a uniform means of evaluating the performance of a communication and tracking system. Several performance measures are proposed and described. These measures can also be predicted using an interactive software program. This program predicts the signal propagation, given the input mine characteristics and layout, with numerical and visual feedback. New or alternative system installations can also be more accurately designed to potentially minimise initial system cost and time required for trial and error installs. The focus of this research is to develop tools and protocols that can evaluate and measure the effectiveness of installed underground communication and tracking systems.

Nov 22, 2011

Among countries afflicted with insLantaneous outbursts of coal and gas, Australia is noteworthy because of lesser disturbances of the seams and of the occurrence of CO2 in the seam gas from place to place. Research sLarted with the 1954 occurrences at Collinsville and Metropolitan Collieries leading to early publications reviewing the problem, describing occurrences and assessing variations in proneness factors in the two affected coal basins.The basic requirements for proneness include coals of high gas sorptive capacity, high ground stress, use of a mining method which provides higher stress concentrations and limits emission of seam gas, including high rates of advance. With CO2 in the seam gas proneness is greater.The mechanism is complex and not fully understood, but involves the coal, the roof, the floor, the gas, the mine opening, the ventilation, the kind of work and the rate of work. Geological disturbances such as faults and dykes increase proneness and tend to localise occurrences. On-occurrence of outbursts in some mines is difficult to explain.Outbursts are seen as a continuing threat to modem deep Australian mining of high rank coal.The simplest contributory factor to reduce is gassiness - despite the low permeability of outbursting coals - and present practices are showing promise. The greatest challenges for the future are partial degasification to below a known threshold figure and confirmation that this reduction is achieved and identification of anomalous geological structures ahead, the most likely locations for instantaneous outbursts to occur. The advances made to date give promise of a future with reducing experiences of uncontrolled instantaneous outbursts. For the Bulli seam particularly, working to achieve prediction and prevention is most urgent.

Jan 1, 1993

By H J. Ross, R K. Beatson, T J, W R. Fright

Traditional method of explicitly defining three-dimensional (3D) ore-waste and geological boundaries relies heavily on a time-consuming process of manual digitisation. This method of modelling can be best described as surface modelling, as complex surface geometry is built up by digitising points that lie on the surface. With the advent of fast 3D interpolation methods, however, construction of geological surfaces using volume functions is now a practical alternative to explicit modelling of surfaces. Unlike explicit modelling, surfaces contained in volume functions are not explicitly defined or digitised. Instead the existence of surfaces in the volume function is implicit, thus the process of modelling surfaces from volume function is called æimplicit modellingÆ. Based on recent advances in fast scattered data interpolation methods, implicit modelling first defines a continuous three-dimensional function that describes the grade or rock distribution. This volumetric function is interrogated for a grade value, or a geological surface, thus allowing the extraction of the 3D object to be automated and eliminating the need to manually digitise surfaces. Since the function is continuous throughout space and does not depend on a mesh or grid for its definition, the extracted geological or grade wireframes can be constructed at any desired resolution in the specific volume of interest. The volume modelling method can work on scattered drillhole data of any data density, including processing combined information from dense grade control data as well as sparse resource drilling. It offers distinct advantages over surface modelling, including: being able to wireframe geological objects that may take days to digitise in tens of minutes; substantial improvement in modelling accuracy; and the ability to generate conditional models rapidly allowing mining risks inherent in geological modelling to be examined.

Jan 1, 2003

The statistical nature of the variability in detonation times of pyrotechnic delays is discussed, and how to evaluate the probability of required detonation intervals is shown. Some methods (analytical and stochastic) are given for designing blasts to ensure that any adverse effects on the variability in the delays is taken into account and minimised. Using computer models of blasts, detonation simulations can be used to check the initiation sequence for the probability of sequence reversals, indicating areas of high blast damage potential. Charge consumption rates, which relate directly to the resulting vibration levels, can be examined for their susceptibility to variation from delay variability. Models that synthesize vibration waveforms for production blasts, when taking delay variability into account, indicate the difficulty in vibration level prediction.

Jan 1, 1992

By Hale C. T, Carnie W. A

Rosebery mine has had over 100 years of mining activity. The reserve has remained static for the last eight years with an expected mine life of six years. A move to rectify this was made in 1994 with the birth of the Deep Exploration Project (DEP). $45 M was committed to drill 100 km of underground exploration diamond drilling and develop 5.5 kin of decline aiming to add 9.5 Mt to the reserves and minimise lead time for development of P and K lenses discovered in the early-1990s. In 1996 this aim was expanded with the objective to build the resource base to 20 Mt by June 2000 allowing the mill to operate at 1.0 Mtpa (0.9 Mt from underground). Preliminary results of the project to-date are outlined and exploration diamond drilling techniques and strategies are described.

Jan 1, 1997

Mount Isa Mines' Hilton Mine was brought into large-scale production in 1990/91 at a time of sharply falling metal prices. To ensure the operation's survival and eventual prosperity there was an urgent need to reduce operating costs and increase revenue. A target of a 40 per cent increase in productivity over five years was set. Strategies to obtain the required improvements were developed on the basis of greater involvement and increased contribution from the workforce, major changes to the mining methods and the development and application of new technology. This paper describes the organisational, operational and technological changes that have been implemented at Hilton and presents the results achieved to-date.

Jan 1, 1993

The article, as written, represents a short account of the treatment of the base bullion from the Broken Hill ores, as carried on at Port Pirie, for the recovery of lead, silver, and gold, and for the treatment of by-products. Appended is a short description of the chief facilities of plant which have been adopted to overcome the main difficulties in the refining of lead the Howard press and stirrer. The article is within the limit prescribed by the regulation for the prize offered by the Australasian Institute of Mining Engineers, comprising 30 pages, containing an average of about 200 words per page, exclusive of analyses, photographs, and sketches.The writer desires to thank those to whom he is indebted for their- kindness in affording him every facility possible to obtain the information which he required for the success of such a paper-viz., Messrs. Robertson, Leavens, and Gronow, of the Broken Hill Propritary Co. Limited, at Port Pirie, and Mr. Crowther, of the Adelaide School of Mines, to whom he is indebted for photographs. The difficulty of obtaining fair samples of gold drosses, and the inability to obtain particulars of fuel consumptions, prevents the paper from being as complete as one would wish. The limited length precludes detail, except in more important parts.

Jan 1, 1907

By Kirkhouse C. B

Soon after the Broken Hill Limited started operations at their Iron and Steel Works at Newcastle, NSW, it was found necessary to install a mill for rolling small merchant bars, rounds, etc.An arrangement of the first mill laid down is shown on Plate 1., Fig. 1. This mill commenced operations on the 18th July, 1917.The feed for this mill was rolled in the existing 18-in. mill and sheared to the lengths required before being delivered to the billet storage yard. The billet storage yard is 90 ft. span, and is served by one 10-ton electric overhead travelling crane. Billets were placed on the billet bed preparatory to being charged into the heating furnace.The heating furnace was of the continuous recuperative with end discharge and had a hearth 40 ft. long by 10 ft. wide. The billets were pushed through the furnace by means of two hydraulic rams, which could either act together and push one row of billets, or act singly and push two rows of billets. This furnace was fired by producer gas from the producers shown on Plate I., Fig. l.The gas was conveyed to the furnace by means of a brick underground flue.

Jan 1, 1935

In seeking to improve the economic performance of mines, the management or human aspects are usually seen to be quite seperate from, and more significant than, the technical aspects. There are obvious aspects of industrial relations, man-management, skills training and supervision that are currently the focus of efforts to improve the productivity and quality of the mining process. However technology also has a lot to offer. Analysis of the costs involved suggests that innovations leading to improvement in the productivity of the excavation and transport of overburden and the recovery of coal (both in the mine and preperation plant) can lead to improvements in the economic performance of a mine that may outstrip the obvious non-technical or management opportunities for improvement. While there are some innovations currently being investigated within the industry that relate to the design of mining equipment, the type of machinery being used in open cut mines has not changed dramatically over the last twenty five years. It is also likely that mining equipment will remain essentially of the same form in the forseeable future. If significant improvements to mining performance are to be achieved other than by futher increases in the scale of machinery, then we need to seek ways to operate these same types of machines in a more productive and controlled manner. This paper discusses the identification of mining processes the improvement of which is likely to have a significant effect on mining costs and performance. Some areas of current research are discussed and potentially fruitful areas for future development are identified.

Jan 1, 1991