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By M Hino, Y Sasaki

Sustainable handling of municipal waste and sewage sludge has an important goal to recycle resources without supply of harmful substances to humans or the environment. The gasification mechanism of phosphorus from municipal waste and sewage sludge during the incineration process has been investigated to develop a phosphorus recovery system. Quadrupole mass spectrometer coupled to an electric furnace is applied to study the vaporisation behaviour of phosphorous gas phases from municipal solid waste (MSW) incinerator ash of sludge during solid-state reduction by carbon. Measurements are carried out in vacuum conditions of 2 x 10-6 Torrs and furnace temperature range 573 - 1773 K, at a heating rate of 7.22 K/minute. It has been found that most of the phosphorus is vaporised as PO2, P2 and P4, in agreement with thermodynamic estimation despite a shift in the temperature regimes.

Jan 1, 2006

By Wakamatsu DT, Nakahiro Y

This present paper deals with the fundamental study of the separation of fine cassiterite and quartz by liquid-liquid extraction using iso-octane as an oil phase, dodecylamine acetate (DAA) as a collector, and sodium chloride as a depressant. With regard to the distribution of fine cassiterite and quartz between oil and aqueous phases, the effect of DAA has been investigated in terms of pH, DAA and NaCl concentrations, zeta potential, and adsorption density. From the results of the experimental work, a maximum recovery of cassiterite in the oil phase was obtained with pH around 6.0, DAA concentration of 1.0 x 10-5 mole/litre, and NaCl addition of 0.1 mole/litre. In these conditions of liquid-liquid extraction, most of the fine quartz remained in the aqueous phase. Thus it was found that NaCI was an effective depressant for fine quartz under optimum conditions. A series of separation tests by liquid-liquid extraction was then conducted for the mixed samples (6.0 per cent Sn) of cassiterite and quartz. By a single separating process, the per cent of recovery of cassiterite in the oil phase was about 92 per cent with a grade of 27 per cent Sn. The same results could also be obtained by using kerosene in place of iso-octane as the oil phase.

Jan 1, 1993

Mother Nature controls, technical professionals model and miners decide. Decisions to explore, mine and mill. Mine decisions, mine design, planning and scheduling are subject to the quality of models û geological models, geotechnical models, resource models, density models. The closer these models are to reality, the more accurate the predicted outcome. So why is it we delegate the modelling tasks to the most junior and least experienced people? If we insist on this, we need to support them û to provide them with æexperience acceleratorsÆ. Technical mentoring is the most effective way to provide the right information at the right time. When this information (read skills) is supplied at the right time we can inject experience into the quality of our modelling and into our decision- making processes. The objective of this paper is to share those behaviours and manners that foster relationships and create frameworks for skills and experience transfer. Central to this is an understanding of how adults learn, an understanding of the basic rules of mentoring etiquette, and the three keys to building meaningful mentoring relationships. An understanding of adult learning processes and styles provides a structure within which a mentor can understand the learnerÆs perspective. Understanding the world from the learnerÆs point is critical to selecting the right language to engage, teach and transfer skills. Basic rules of mentoring etiquette like timeliness, respect and trust need to be brought into the consciousness so they can be agreed on and monitored to prevent conflicts in cultural and generational norms between the mentor and the learner.Meaningful relationships hinge on the three behaviours: truly listening, rather than just hearing; understanding the technical issues within the WIIFM (whatÆs in it for me?) question; and facilitative behaviour. Stronger and more meaningful technical mentoring relationships within our industry will bridge the generational gap and ensure we can capture and capitalise on the wealth of grey hair experience and develop an informed group of young decision-makers.

Jan 1, 2006

By M C. Schodlok

Banded iron-formation (BIF) and iron ores were measured using the CSIRO developed TIRHyLogger ™ to assess its ability to map quartz, carbonates and riebeckite. The TIR-HyLogger™ measures continuously spectral refl ectance data from diamond drill core or drill chips with a high spatial and spectral resolution. Samples from twelve BIF, bedded iron deposits (BID) and channel iron deposits (CID) have been analysed. The spectral data were processed with two different approaches. The first approach, focused on the identifi cation of the major minerals, was performed using principal component analysis (PCA). It identified four minerals (quartz, ankerite, riebeckite and goethite) and provided pure spectra called end-members. The second approach included a mineral diagnostic spectral feature extraction involving wavelength position, relative peak heights and relative depths of absorptions. Quartz has a diagnostic absorption at 8.625 µm and ankerite shows a refl ectance peak at 11.275 µm. In addition to the identified end-members, two carbonate populations (calcite and siderite) and two silica species (quartz and amorphous silica) were identified.

Jul 11, 2011

By M Ahler

Future developments in the mining sector will be driven by the need to increase safety, ecological sustainability and efficiency. Autonomous systems represent a huge step towards achieving these goals. This paper describes the basic infrastructure of an autonomous system – essentially a network of distributed sensors. Although the sensors are distributed, the overarching communication network with its related middleware offers a transparent and uniform layer. This middleware acts as an abstraction layer which priorities information and provides information to other platforms on request. This permits higher-level autonomous functionality to utilise all information available in the system regardless of where data has been generated or via which physical communication link it has been processed.The Personnel Proximity Detection (PDD) system is described in detail as an example, with details not only of the system itself, but also of the essential full integration and how the abstraction layer allows this technology to be plugged in at any location of the network. The paper ends with a summary of the content and a conclusion.

Nov 22, 2011

By B Belle

"Mines around the world are inherently and operationally diverse. Current methodologies for the design of mine ventilation and cooling infrastructure involve controlling major safety and health hazards. Globally, it can be estimated that mine ventilation systems from various commoditiescirculate over 150 000 m3/s of exhaust air through shafts. Additionally, over 2 000 000 workersare transported every day through shafts in labour-intensive mining countries like China, India,Southern Africa, and the Americas. A key objective of this paper is to share experiences and provide a case for the revision of ætime-honouredÆ ventilation design parameters based on a benchmarking exercise on design exhaust shaft velocity from various global operations (gold, diamond, platinum, coal and base metals). An active fi eld observation on exhaust shaft velocity has indicated that, regardless of the commodity or continent where the mine operates, almost all life-of-mine (LOM) design parameters provided are in the same range of 20 m/s to 22 m/s, which is not convincing considering signifi cant variations exist in shaft depths, geography, commodity, operating and capital costs. From a due diligence perspective, there are no documented views that are available on the most widely used design exhaust air velocity. Based on the global exhaust shaft velocity data, it is noted that a significant portion of shaft velocities are outside the current design velocity of 20 m/s (some operating up to 30 m/s) and other signifi cant portions of the exhaust shafts operate in the critical velocity range. In the case of Australian coal mines, limited data suggests that none of the mines have ever reached the LOM design exhaust shaft velocity. It is self-evident that when the shafts are not operating at their design quantities either the mine system resistance is low or the ventilation and main fan is operating ineffi ciently. The most common reasons given for not reviewing the shaft system were, ætime-honouredÆ design parameter are being used and cannot be changed, mine fan pressure limits, possible fan blade damage, possible spontaneous combustion risks, leakage or simply did not consider such a possibility. In conclusion, the study has reiterated the historic lessons that a safe and expensive airway should not be utilised uneconomically by circulating too litt le air through it."

Jun 1, 2012

By R Cooksey

The Globe-Progress Mine is an open pit gold mine that is part of the larger Reefton Goldfields deposit located on the West Coast of New Zealand. The regional geology comprises a series of north to south oriented fold structures that have undergone post-deformation mineralisation. The structural geology within the mine itself is more complex, with major shears hosting numerous high-grade mineralised quartz shoots and splays that have been historically mined.The selective mining of ore within the pit is challenging due to the orientations of the hanging wall and footwall areas of the main Globe shear zone, the lithologies of these areas which range from highly brecciated and sheared material to competent mineralised host rock, and in the hazards presented by the numerous old historic underground workings. The coordination of drilling, modelling and excavation of the ore requires careful planning to maximise recovery whilst operating with the pit design boundaries.Grade control packages are custom designed to reflect the orientation of the footwall and hanging wall mineralisation. The shear material in the footwall zone dips between 60° and 70° and requires angled drilling whereas the footwall mineralisation is contained in shallow dipping quartz veins sub parallel to bedding and can be vertically drilled to best intercept the mineralisation. Ore excavation is directed so that the contact between the footwall and hanging wall is mined in the correct direction so that any non-visual ore contacts can be safely mined and that the ore-waste dilution is reduced.The ongoing grade control and selective mining of the Globe Progress deposit continues to deliver high grade ore for processing by ensuring that waste and dilution of ore is reduced and that recovery is maximised.

Aug 22, 2011

By S B. Sheldon

Wall control programs tend to be expensive and consequently require financial justification in order to get approval for the expenditure required. The difficulty faced in getting this approval is that the outcomes of a wall control program are all subjective – a prediction of wall stability and what the wall would do with and without the program. Determining a net benefit is difficult and often justification of a wall control program is based on gut feel, history and a good selling campaign to build a perceived need.This paper outlines a simple solution to this problem by applying risk management principles to wall control. The process is to identify the risks to the operation associated with current wall conditions and then build a risk database for different potential scenarios for each risk. A financial impact is assigned to each risk scenario to complete the database. A consequence and likelihood analysis of each of the risks is undertaken and a formula applied to estimate the projected cost to the operation for the current risk profile. The process is repeated for the predicted wall control conditions after the application of the wall control program. A successful wall control program will reduce an operation’s risk profile so this projected cost should be less than that calculated for the current scenario. The difference in the two projected costs is the value that the wall control program has produced and this value can be used to determine the net financial benefit potential for the wall control program.This methodology can also be applied to other improvement programs that focus on risk reduction such as vibration control.

Nov 8, 2011

By S W. Houlding

The Certificate in Mining Studies program at the University of British Columbia, Vancouver, Canada is a collaborative initiative between mining schools and industry to provide accessible, cost-effective, accredited continuing education and training, designed to address the future needs of the global mining community. Content is provided by industry specialists and delivered through an integration of online learning, short courses and interactive webcasts. Accreditation is provided by a network of mining schools. In 2011, the program will deliver close to 100 short courses and interactive webcasts and provide 24/7 access to more than 130 online courses in six mining streams, to participants from as far afield as Tanzania, Argentina and Mongolia. The program is proving adaptable to corporate and mine site engineer-in-training and graduate-development programs, as well as providing accessible professional development opportunities for individuals. It also provides opportunities for cross-training from other disciplines and integration with mining school curricula.

Nov 22, 2011

By J Elder

Magnetic separation equipment has long been used to upgrade and beneficiate a wide variety of minerals and materials. Over the years, significant advances in both wet and dry magnetic separators have improved their operability and separation performances, broadening their use.But no one answer exists to the question: what is the right type of magnetic separator? For many minerals, including ilmenite, both process routes may be viable. There are technical, production, as well as economic reasons for choosing wet versus dry. However, recent developments illustrate that a new generation of wet magnetic separators is approaching performance once seen only in dry magnetic separation. With quality and production performance becoming similar, the choice between wet and dry magnetic separation is not as cut and dry as it once was.

Oct 5, 2011

By B Haase, R Saha

Conditional simulation (CS) has been extensively used in metal industry to assess uncertainty of geo metallurgical variables to build robust distributions around grade tonnages across different time horizons. Coal’s entry to nonlinear stochastic modelling is relatively new and this paper summarises the work done at BHP to enable its practical usage from production time frames to Life of Asset planning. CS in coal using Sequential Gaussian Simulation (SGS) is used to understand resource confidence around specific variables within pre-defined boundaries of spatially continuous domains for each coal seam. The variation between simulations for a given parameter reflects uncertainty. This paper demonstrates the use of CS to profile resource based upon agreed seam/parameter uncertainty thresholds which affect planning, forecasting, extraction and inform identification of key production risks and defining mitigation strategies. The end goal is to de-risk long-term plans by optimising infill data collection and improve stability in short-term planning through increased understanding of confidences locally rather than at global resource definition stages. The paper also briefly discusses the use of automated workflows and systems to minimise the time spent on the process to enable use in decision-making.

Mar 22, 2022

By Huleatt M, Perkin D, McLeod I, Mock C, Pratt R, Gourlay A, Timoney E, Knight N, Ward J

Generally speaking, Australia's reserves of its more important minerals (in terms of export earnings) are adequate to sustain forecast rates of production to the year 2000. The rate of forecast production increases of these commodities (aluminium - whether as bauxite, alumina or metal, black coal, iron ore and ferro-alloy minerals, base metals, tin, uranium, and mineral sands) reflects a well- ordered and sustained growth phase of Australia's mineral industry.

Jan 1, 1981

By N Winkelmann

Underground coal heating is a significant hazard in some coal mines. The broad principles of how underground coal heatings occur is reasonably known, however the technique for locating the heatings in often inaccessible goaf has been proved to be difficult. Since 2002, CSIRO, with the support of the Australian Coal Association Research Program (ACARP) has been undertaking investigations to apply and develop innovative surface-based radon technique for locating the underground heatings in Australia. This paper presents the progress of the investigation.

Jan 1, 2005

By S Ravn

Under platform exhaust (UPE) systems are often designed into metro stations as a means of removing heat generated by trains as they come to a halt in the platform. These systems are designed to extract heat from the brakes and brake resistors directly at the source in order to capture as much heat as possible before it can enter the public areas of the station, or contribute to the temperature build-up in the tunnels. Due to space requirements for the associated duct and air handling units, the UPE plays a significant role in the geometric design of the platform and station as a whole.In recent years questions have arisen as to the effectiveness of UPE systems. However, very little data is available for designers to use when making important decisions on the station designs for new metro systems. This is important as significant savings could be achieved by omitting or re-designing these systems for new build stations; not only due to the capital costs of space provision for the duct itself but also due to the associated operation and maintenance cost of the UPE system.This paper will present recent measurements of the UPE system of the Copenhagen metro together with one-dimensional (1D) simulations, looking at typical dispersion of heat into the station plenum box and air exchange through draught relief shafts as the train enters the station in order to evaluate the effectiveness of the UPE system. The aim of this paper is to disseminate the results of measurements and analysis to increase awareness of the issue and to provide discussion relevant to designers in their evaluation of heat removal systems in new build station designs.

Mar 8, 2011

Just as geophysics, in the form of 3D seismic and wireline logging, plays a key role in petroleum reservoir management, so too will geophysics play an important role in mining of coal, metals, and minerals in the 21 st century. The commercial and social imperatives driving greater use of geophysics are reduced costs, increased revenues, and enhanced safety. In short, superior utilisation of capital and management of risks. In relatively undeformed sedimentary environments it is possible to adapt petroleum-style 3D reflection seismic to image mines. This has been demonstrated most impressively in the Witwatersrand. Anglo-American, for example, completed a $1 million 3D seismic survey at Western Deeps in order to site a new $300 million shaft with confidence. Likewise, 3D seismic has gained rapid acceptance at Australian coal mines in recent years. Encouraged by these successes, metalliferous mining companies are supporting research in Canada and Australia, as well as South Africa, to adapt 3D seismic for more highly structured, metamorphic terranes. Because the mining industry is far more diverse than the petroleum industry in terms of commodities and geological environments, 3D seismic is not always cost-effective. A plethora of other geophysical techniques can be applied, many of which are employed in mineral exploration. Mine applications of geophysics differ from traditional exploration applications in two main ways: time scales and length scales are shorter, and boreholes are more plentiful. Borehole geophysical techniques therefore play a more significant role, both for logging and imaging. Logging systems detail the variations of in situ physical properties down the borehole at scales measured in centimetres, while geophysical imaging techniques can map features located tens or even hundreds of metres from the sensors. While geologists tend to think of boreholes in terms of chips and core, geophysicists perceive them first and foremost as access paths for instruments. Borehole logging has been employed at iron and coal mines for decades, mainly to accurately define ore boundaries in delineation holes. In base metal mines, Outokumpu implemented logging widely for orebody delineation in percussion holes in the 1980s. The benefit was a direct cost-saving, arising from substitution of core drilling with percussion drilling plus borehole logging. The practice has since spread to other companies. INCO, for example, defines nickel boundaries in blast holes at Sudbury using conductivity logs. The benefits are in the form of reduced dilution and enhanced ore recovery, flowing from a more accurate mine model. Density, natural gamma radiation, magnetic susceptibility, and conductivity are the principal metalliferous mine logging parameters because they can be recorded in both dry and water-filled holes. Sonic velocity is the premier geotechnical logging parameter, given its sensitivity to rock strength, stress, porosity, and degree of fracturing. Sonic is recorded routinely in exploration and geotechnical holes at coal mines. With the advent of slimline dipmeter, full waveform sonic, and optical and acoustic scanner tools, the role of borehole logging in geotechnical evaluations is expanding. Monitoring of strain and micro-seismic activity enhances safety during mine production. While qualitative interpretation of logs is adequate for stratigraphic identification or definition of boundaries, a wealth of quantitative information, eg density, can be derived from properly calibrated, repeatable geophysical logs. Moreover, geophysical logs can sometimes serve as surrogates for geochemical assays, and not only for magnetite and uranium. At OutokumpuÆs Kemi chromite mine, for example, gamma-gamma logging provides the basis for grade control. By reducing reliance on assaying, three benefits can be realised: reduced reliance on core drilling; lower core handling and assaying costs; and shorter turn-around times. Conventional downhole EM and borehole magnetics are used for near-mine exploration, and for ground sterilisation. Inco has enjoyed considerable success with borehole UTEM in the Sudbury Basin, for example, and Geopeko has applied three-component borehole magnetics successfully in the Tennant Creek area. Electrical techniques such as applied potential and magnetometric resistivity (MMR) are also finding application at mines. For higher resolution, borehole seismic, radio imaging, and radar have been invoked, with varying degrees of success, to delineate orebodies and map structures, or to geotechnically characterise the rock mass and identify hazards. Success mapping nickel sulphide shoots with borehole radar has been reported by WMC at Kambalda. There are no universal geophysical panaceas, and each mine imposes different geological, logistical, and economic constraints. Geophysics will not always be cost-effective. However, the greatest single impediment to expanded use of geophysics at mines has been the low level of awareness of geophysics on the part of most mine geologists, engineers, and managers and, equally, the limited understanding of mine geology and engineering exhibited by the majority of geophysicists. This myopia will be remembered as a 20th century affliction! Blue Sky areas for mine geophysics in the next ten years include integration of geophysical data acquisition with drilling, enhanced grade estimation and rock mass characterisation, and the incorporation of geophysical information into mine models using geostatistical techniques. All these advances will be predicated on an expansion of petrophysical knowledge.

Jan 1, 2000

By Bisshop J. P W

Maximum recovery of sulphide minerals by flotation is achieved over a limited size range. Valuable particles above and below this range have a smaller probability of being recovered. In the normal grinding-flotation operation, not all valuables are reduced to the optimum size range, and therefore sub- stantial losses occur. A significant improve- ment in the size distribution is not usually possible within the conventional circuit, and a more complex arrangement may be necessary to obtain optimum recovery of the valuable mineral. This problem is considered with refer- ence to the Mt. LyeZl concentrator. The performance of the existing circuit is dis- cussed, and it is shown that losses in recovery occur in both coarse and fine sizes. Laboratory tests indicate that regrinding the coarse particles results in an increase in recovery of up to 4%. Redistribution of plant grinding capacity to reduce initial grinding power by 6% and use this capacity to regrind coarse particles was considered. It is con- cluded that overall plant efficiency would be increased by 2% provided that overloading of the regrind mill could be avoided.

Jan 1, 1977

By Mckenzie CK

Delay scatter, although widely recognised, has rarely been studied with the aim of critically reviewing blast designs. With current trends towards increased deck charging, and the effect on the number of separate delays in blast designs, delay scatter is shown to have a rather profound influence on the control of initiation sequence and the ability to successfully con- duct pre-splitting and smooth blasting. Determination of realistic delay scatter distributions is the first step towards application to blast design. Delay scatter must be evaluated in terms of deviation from the nominal time, not in terms of deviation from the batch mean, since the latter is not usually known without specific testing, requiring accurate timing instrumentation. Computer programs using Monte Carlo simulation can then be developed to investigate the probabilities of out-of-sequence initi- ation or near-simultaneous initiation within any specified interval. The procedures have been applied to both production and development blast designs in Australia and Chile to improve initiation sequence control and to rationalise and simplify blast designs.

Jan 1, 1988

Introduction The mine winder is an essential element in the mining of ore in deep level mines and therefore requires a high degree of reliability to avoid interruption of production. Failure of any component on a winder may also be dangerous and expensive to repair. The larger the failure the larger the stoppage. The failure of a winder drum is the ultimate catastrophe, not only because of the cost of replacement, but also because of the lead time in procuring a new drum. Today these types of failure are not as common but many failures have occurred in the past and even today many an old winder is con- sidered for a new and often more arduous duty. As far back as the turn of the century a lot of information had been gathered to try and clear up the complexities of the multi- layering effect of coiling rope under tension onto a drum. Before comparing results obtained by various researchers the nature of the pressure distribution between rope and drum due to multi-layering will be discussed briefly.

Jan 1, 1987

The longwall system with caving is the most common mining system in Polish Collieries and the extraction is carried out simultaneously on several levels and in different seams. The extent and diversity of the methane hazard occurring is strictly connected to the specific geological and gas conditions as well as to the applied mining methods. Taking these factors into consideration the following methane drainage methods are applied as additional means of combatting the methane hazard in Polish gassy coal mines: 1. predrainage by means of boreholes drilled from the surface, 2. predrainage from stone drivages and devel- opment workings, 3. degasification of coal extraction workings, and 4. degasification of sealed-off areas/old goaves. Predrainage gave satisfactory results when holes were drilled from the surface or from underground workings, but only to depths to 300 m. It was necessary to adapt methane drain- age methods to the geological and mining con- ditions as gassiness increased with depth. The results of methane capture, both pre- drainage and post drainage were obtained by investigating several gassy mines.

Jan 1, 1982

By Palmer DJ, Bain JH, Pullen JB

Over the last ten years at Risdon, zinc production capacity has almost doubled. This has resulted in modifications, many of which have affected zinc deposition operating conditions in the cells. Some of these changes appeared to have affected average current efficiency to such an extent that a special investigation was initiated, using multiple regression analysis to assess historic cell unit operating para- meters. The study highlighted the importance of certain parameters in maintaining maximum current efficiency for zinc deposition from !Risdon purified solutions under conditions of !changing current density, acidity and zinc con- centrations. Maximum current efficiency was obtained only within a zinc to acid ratio in cell electrolyte of 0.45 - 0.55 and a residual zinc concentration greater than 48 g.1-1, irrespective of actual zinc concentration or The investigation also established: ieters giving minimum power consumption at termined current density; the effect of ntration changes in common impurities on nt efficiency; the existence of high s of some impurities in solids precipit- in the cells and pure solution tanks.

Jan 1, 1975