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By Kuwasaki N, Mitsune Y

Many activity measurements of components in liquid oxides have been reported in the field of slag chemistry. However, very little is known about the thermodynamic behavior of compo- nents in oxide solid solutions. In the present paper, e.m.fs. of the follow- ing galvanic cells employing solid electrolyte Zr02(CaO) were measured on the entire range of composition of the solid solutions. Pt/Ni-(Mgl-x ix)O/ZrO2(CaO)/Ni-NiO/Pt Pt/Ni-(Mgl-xNix)2SiO./ZrO2(CaO)/Ni-NiO/Pt Pt/Ni-(Mg l-xNix)Si03/ZrO2(CaO)/Ni-NiO/Pt. Activities of NiO in these solid solutions of (Mgl_ Nix)O and (Mgl_ Nix) 2Si0a(where 0

Jan 1, 1980

By R Schmitt, Y Ghorbani, I McElroy, N J. Bolin, M Parian

Aitik is a large copper porphyry type deposit located in northern Sweden, currently exploited at an annual rate of approximately 45 Mt. The ore’s exceptionally low head grade of 0.25 per cent Cu and varying degrees of hardness across the entire deposit pose challenges to the two fully autogenous grinding lines, each of which comprises a primary autogenous mill in series with a pebble mill. The variability in ore grindability frequently leads to fluctuations in mill throughput. Within the framework of a geometallurgical approach, the present study investigated the relationships between ore grindability and modal mineralogy. For this purpose, drill core samples from different lithologies were subjected to Boliden AB’s in-house grindability tests. This fully autogenous laboratory-scale test generates a grindability index mainly related to abrasion breakage, which is a significant breakage mechanism within autogenous mills. The test results suggested divergent degrees of grindability within and across the selected rock types. A combination of scanning electron microscopy, X-ray powder diffraction, and X-ray fluorescence analyses was performed for the grinding products and bulk mineral samples. The resulting mineralogical and elemental properties were subsequently correlated to the parameters from the grindability tests. It was shown that the main mineral phases, such as plagioclase, quartz, and micas, correlate well with the grindability indices. Similar correlations were found regarding the sample’s chemical composition, attributable to the main mineral phases. A further inverse correlation was established between the sample’s calculated average Mohs hardness and the grindability indices. Moreover, mineral liberation information provided by scanning electron microscopy was associated with the parameters mentioned earlier. The identified relationships between grindability, modal mineralogy, and element grades may help Boliden develop a predictive throughput model for Aitik based on the mine’s block model.

Aug 24, 2022

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

IN this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but scanty attention in order that others may be rather more fully dealt with; for instance, figures referring to the accuracy of various methods of valuing alluvial deposits, particulars of efficiencies, and water duties on both overburden and drift; also, the system of recording water distribution, &c.The plans of the tin-streaming shed, sluice and feed·race, and overburden tail-race represent types of the most modern design.The principal alluvial deposits being worked at the present time are situated either in the ancient or modern bed of the Ringarooma river or its tributaries. This river flowed in a north-easterly direction, receiving numerous tributaries on either bank, and finally emptying into Boobyalla harbour. The most important of these tributaries, from a mining point of view, are the Cascade, Main creek, Weld and Frome rivers (which unite just before joining the modern Ringarooma), Wyniford river, and Bradshaw's...

Jan 1, 1911

By L R. Sousa, M He

Rock burst is common in deep underground excavations and is characterised by a violent ejection of block rocks from excavation walls. It is critical to understand the phenomenon of rock burst and particularly the failure mechanism. Laboratory experiments are one of the ways. For that purpose, a rock burst laboratory test system was developed at the State Key Laboratory for Geomechanics and Deep Underground Engineering at the China University of Mining and Technology, Beijing. A true triaxial test system, designated the Deep Underground Rock Burst Analogue Test Machine, was developed, which can transfer a stress state from three-direction-compression on six surfaces to the compression on five surfaces with one set free. The rock burst experimental system comprises an acquisition of acoustic emission signals, a high-speed recording in order to accurately record the kinetic characteristics of rock fragments ejected during a rock burst event and the possibility of infrared thermography showing the surface temperature of the samples. In this paper, analyses of typical results from rock burst tests are presented with a description of the obtained results. The mechanisms of rock burst are illustrated, and a rock burst classification is proposed based on these laboratory tests. For the control of rock burst, the constant resistance, large deformation (CRLD) bolt or anchor is presented for accommodating the large displacement of surrounding rock masses and absorbing the impact of the sudden release of rock burst while outputting a constant resistant force in response to the external load. The CRLD bolt or anchor has had practical applications in underground mines. Finally, in situ tests performed in a tunnel at Qingshui coalmine, China, are analysed in detail.CITATION:He, M and Sousa, L R, 2014. Experiments on rock burst and its control, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 19–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

In the last 40 years, New Zealand has developed a number of liquid- dominated geothermal steam fields, for electricity generation and indus- trial process steam. New technologies were developed, and in this work, New Zealand led the world. The policy of full publication of the results, in a wide range of sciences, provided a reservoir of detailed data defin- ing the geology, size and shape, and the chemical and physical regime, of many geothermal fields and their constituent parts. The discovery of precious and base metal deposits /precipitates in geothermal drill cores and steamfield equipment, suggested a clear link- age with epithermal mineral fields in general, and with that of the Coromandel (Hauraki) Region in particular. Further work on geothermal/ epithermal relationships have implied that the techniques, developed to obtain an understanding of geothermal fields, could be applied also to epithermal mineral exploration. This work is developing fast, and is now proceeding in many coun- tries. Future work may show that the presumed relationship between geothermal and epithermal deposits may be applicable in the wider con- texts of all hydrothermal deposits, and possibly in many other minera- lised areas with volcanic "country rocks".

Jan 1, 1988

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

Autogenous and Semi-Autogenous grinding has become an accepted method of reducing primary crusher product to micron sizes in a single or a two-stage grinding circuit. The elimination of secondary and tertiary crusher circuits and sometimes rod mills helps to lower overall operating costs and, in many instances, can make uneconomical projects viable. Selecting AG/SAG Mills have been rather a "hit and miss" affair over the years, but now with the many different types of tests available, accurate mill size predictions can be made, provided the test data is evaluated correctly. This paper endeavours to simplify the process of evaluating test data and sets down some guidelines for designers to follow when selecting AG/SAG Mills.

Jan 1, 1991

By Bernard G, Limpach R, Ulveling L

A major aspect in competitive ironmaking is to replace metallurgical coke by injecting alternative cheap fuels. Whereas in the past, heavy oil injection as well as on a lower scale natural gas injection have proved to be reliable, the progressing high price level of these fuels has prompted international interest in looking for alternative cheaper fuels, especially pulverized coal. Theoretical analysis and practical operations showed that for constant adiabatic flame temperature, potentially more coke may be replaced by injected coal than by heavy oil, because of less endothermic cracking of hydrogen components. Since about 1974, the ARBED-Group has been looking for alternative fuels and in 1976 came to conclusion to select for first trials pulverized lignite for the following reasons:

Jan 1, 1981

By D J. Brake

There are many sources of gas in underground mines including development and production blasting, strata gases, spontaneous combustion, diesel equipment, chemicals used for a wide range of functions, welding activities and fires.It is only in relatively recent times that electronic gas monitors (or detectors) have become both safe and affordable for routine use.In modern mines, gas monitors should be in daily use by the ventilation department as well as blasting re-entry (or clearance) crews, and are often used by drilling crews, shift supervisors, hygienists and mine rescue or fire fighting crews.When first released, electronic gas monitors needed to be sent off-site periodically for calibration at a suitable accredited laboratory. Between calibrations, their accuracy was unknown. More recently, ‘bump testing’ and field calibration has become possible on the mine site, improving both reliability and safety as well as reducing the total number of gas monitors that need to be in use.There has been almost an overwhelming increase in the number and sophistication of gas monitor features in recent years. This paper reports on a case study into the key criteria that ventilation practitioners should be aware of with respect to the specification and selection of the most recent gas monitoring systems, and recommends good practice for site-based operation and calibration.CITATION:Brake, D J, 2015. Specification and selection of hand-held gas monitors (detectors) for underground mines, in Proceedings The Australian Mine Ventilation Conference, pp 143–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By J D. Grobler

In the heavy minerals industry wet high intensity magnetic separators (WHIMS) are widely applied for primary magnetic separation of magnetic minerals and non-magnetic minerals. This piece of equipment is well known for its robustness to handle a wide range of feed conditions and still produce stable product qualities and yields. A heavy mineral production plant aimed to increase production through their WHIMS plant containing 11 duties and 26 units. Instead of adding new units an alternative approach was followed to firstly maximise the efficiency of the current circuit and secondly to consider possible reconfiguration of the circuit to produce additional product tons for minimal capital investment. In order to characterise the current circuit’s efficiency, identify pockets of excellence and determine the areas for improvement the whole circuit was surveyed several times and mineral mass balances were drawn up.This paper aims to: discuss the modelling process of the WHIMS circuit,explain the calibration and validation process followed to ensure the accuracy, anddemonstrate the sensitivity analysis performed on the different options. From this analysis an efficiency criteria was developed to compare different circuit configurations that enabled the production plant personnel to make an informed decision on the way forward.

Oct 5, 2011

By Beamish B. B

In this study, a systematic examination of the scale and variety of micro-structures in coal using Scanning Electron Microscopy (SEM) has been carried out, using coal samples of differing stages of coalification from the Bowen Basin and New Zealand. SEM provides detail of various micro-structural features and shows that a variety of micron-sized fractures and cavities are present in coals. These are differentiated into three pore types: fracture porosity, phyteral porosity and matrix porosity. Fracture porosity is generally associated with bright coals (although it has been shown that micro-fractures are present in maceral fragments from the dull coal layers). Characteristically the macro- and micro- fractures form a continuous structural fabric through the bright coal layers and thus make a significant contribution to overall permeability. The macro- and micro-fractures appear to have been formed during the process of coalification rather than being formed due to shrinkage during methane extraction, as most of them are infilled with secondary minerals. In contrast, phyteral and matrix porosity is associated with the dull coal layers that are composed of plant fragments or a heterogeneous mixture of macerals. Like the macro- and micro-fractures, the continuity of the observed cavities suggest that these too are a significant contribution to overall permeability, and therefore play a major role in the transmissibility of methane at a level between diffusion at the micropore level and laminar flow at the macro-fracture level. Due to different spacing, orientation and persistence of individual fractures and cavities, the rate of methane transmissibility through a coalseam will vary according to coal rank, coal type and the organic precursors from which the coal was derived. This is important as a knowledge of the micro-structure system and its relationship to coal type and coal rank, plays an important consideration in: a) gas drainage modelling, b) enhancing permeability by inducing fractures and c) predicting the occurrence of outbursts.

Jan 1, 1991

The Bureau of Mineral Resources has been engaged in regional geological and geophysical field work in the Alligator River and Cobourg Peninsula area since 1971, following the discovery of major uranium deposits. Geophysical work commenced with a regional airborne magnetic and radiometric survey which was followed up by some helicopter and ground work in August 1973. The interpretation of the earlier radiometric work is presented in conjunction with the results obtained from the follow-up work. Analyses of 100 outcrop and drill core samples collected have provided basic information on the physical properties and concentrations of uranium and thorium in various rock types. The uranium determinations were made by X-ray fluorescence and delayed neutron analysis, good agreement being obtained between the two methods. X-ray fluorescence was the main analytical technique used because of its ability to produce both uranium and thorium determinations.

Jan 1, 1975

Firedamp drainage has become an essential part of many mine environmental systems, and new applications are arising. Installations are evolving further to satisfy ever changing basic requirements, standards, and iniilny needs. In this paper, water seal, vacuum based installations are considered, as well as moni- toring, protective and control systems which have been developed for continuous, manless, and trouble free operation. Some factors affecting plant capacity and extractor per- formance are identified and assessed. INTRODUCTION Firedamp drainage applications are incr- easing world wide as mining engineers strive for improved safety and security, and further concentration of coal output. Fewer and fewer mines are able nowadays to satisfy coal prod- uction and firedamp control requirements solely by air dilution or by air dilution and underground firedamp extraction plants. As a result, dependence on surface extraction plants is increasing. This paper deals with som requirements and applications of such installations. I. DEVELOPMENT AND PRACTICE Firedamp drainage has existed for over 250 years following the early work of Carlisle Spedding at Whitehaven (1730). Some fundamentals of current firedamp drainage systems can be recognised in the

Jan 1, 1982

By Hargraves AJ

Pre-drainage experiments have been conduct- ed at Appin, Cook, John Darling, Leichhardt, Macquarie, Metropolitan and Moura No. 2 Collieries. Appin (550 m deep) experiences particular gas problems in development drivages, and the almost pure CH4 seam gas makes difficult tiro compliance with statutory maxima in intakes and returns. Patterns of 43 mm diameter drain- a,.;e holes drilled ahead and laterally into virgin coal have improved gas conditions in working places and have allowed tolerable advance rates. Cook, Leichhardt, Metropolitan and Moura No,. 2 Collieries have experienced gas and stress phenomena ranging from conical bursts less than one tonne to full scale instantan- -us outbursts of hundreds of tonnes with tens ,f thousands of cubic metres of seam gas. Gas ~Irainage experiments with patterns of holes up a,, 200 mm diameter have been undertaken with ;,;siness monitors on the coal to establish .lative effectiveness. Incremental flows into mg 43 mm diameter boreholes have investigated drainage patterns relative to length, and at comparative incremental flows have nlicated lowered permeability zones at stress ,.,utments. In some CO2 seam gas areas where iammability problems are reduced to perhaps ii, but where outbursts proneness is increased,

Jan 1, 1982

By E C. Holloway

"The financial valuation of mining assets has a number of fundamental differences to the valuation of many other asset groupings. One such difference is that typically, the greater proportion of both the cost and revenue sides of the cash flow are inherently governed by systemic market forces.As a result, the range of outcomes for the valuation of each mining asset is more unpredictable, with higher levels of risk and uncertainty. In contrast, the management function of many other non-mining businesses or industry groups can control at least a portion of the cash flow by maintaining the margin or controlling the sales price. The management teams of mining businesses and operations typically have limited options, and are thus price-takers for both costs and revenues. As mining is an inherently cyclical industry, large, long-life operations can exist through several price cycles, making valuation both subjective and challenging.The outcomes of both static- and stochastic-based valuations, as well as the internal probabilities of the associated cash flow statements, are significantly impacted when the correlations between the appropriate parameters are quantified, modelled and incorporated into the valuation framework. The appropriate parameters for correlation modelling primarily include those that are governed by systemic market forces. Applying this process results in a different risk profile for the asset by allowing the risks resulting from systemic market movements to be more accurately quantified and then objectively minimised. This process also reduces the level of residual uncertainty in the valuation outcome.This paper presents a valuation methodology to pragmatically incorporate this level of valuation sophistication and statistically quantify the associated increase in the level of confidence of the valuation outcomes reported.CITATION:Holloway, E C, 2016. Correlated valuation methodology, in Proceedings Project Evaluation 2016, pp 181–200 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

The green field discovery of a two million ounce high-grade refractory gold ore deposit in the Indonesian Province of Sulawesi Utara, led Newmont to utilise its proven technical expertise in dry grinding and whole ore roasting to develop a 2000 tonne per day, 160 000 ounce per year operation in this remote and picturesque location.Located at an elevation of 250 in above sea level and ten kilometres to a deep water natural harbour, the hard rock open pit mine, process plant and infrastructure facilities were built to budget at a capital cost of US$132 million. The plant was commissioned with oxide ore, with the first gold poured in March 1996 and with refractory ore in January 1997. The operation rapidly met its production targets because of extensive forward planning and training programs developed for the local workforce. The presence of steep topography, fertile coastal plains, high rainfall, high seismicity of this location led to the decision to dispose of neutralised tailings in deep water off the coast instead of impounding tailings in a dam. This paper describes the development of the project and the challenges in developing a gold operation in a remote location which lacked infrastructure, the steps taken to ensure a smooth commissioning, and the selection of the workforce to operate a technically sophisticated facility.

Jan 1, 1997

By A G. Noble

Tunnelling for hydro-electric power projects can be a very challenging component of the overall development. In contrast to urban transportation tunnelling where the logistics for access and supply of power, water and other essentials are readily available, hydropower projects are usually in very remote locations and all necessary plant, equipment, spares and materials need to be brought in and the site must function as a self sufficient unit.For a large scheme the river diversion tunnel(s) are usually on the initial phase critical path in order to meet the non-negotiable deadline of river diversion before the onset of the wet season. A newly formed tunnelling crew, once mobilised to the site for the project, will face the first major learning curve of the project’s systems and logistics during this critical tunnelling activity.Power tunnels convey the water to the turbines in the powerhouse and are usually on the critical path for the main works, especially if the scheme comprises a powerhouse located within an underground cavern. A modern cavern arrangement requires a complex warren of various openings: access adits, ventilation/cable tunnels, shafts, surge tunnels, etc.Hydropower tunnel construction tends to be dominated by tunnel boring machine (TBMs) or drill-and-blast excavation techniques and each has its challenges in very remote locations. TBMs still have long lead times as for any type of project, but additionally require a thorough roads and bridges infrastructure assessment of the country from the port of entry to the site to ensure a problem-free delivery. In some cases the project also requires the establishment of a complete precast concrete segment production facility and the space for creation of laydown areas; there is no ‘just-in-time’ delivery mechanism applicable to typical remote hydropower sites.This paper highlights the technical and risk management considerations in the planning, design and construction of tunnels for hydropower projects. It contrasts the typical factors that govern the design of urban transportation tunnels with those for remote hydropower tunnels. The perspectives of stakeholders are provided including those of international lenders. With examples from large and small scale projects across the globe it provides an insight to all parties and in particular, those tunnellers that are working in the hydropower field for the first time.

Mar 8, 2011

By H Hoogvliet

The Goondicum Crater industrial minerals deposit is located about 30 km east of Monto, Central Queensland, Australia. Early exploration programs in the 1990s found alluvial ilmenite along the banks of the Burnett River. This mineralisation was traced upstream to the Goondicum Crater. The Goondicum Crater is a topographic feature centred on a roughly circular 6 km diameter layered gabbro complex. Significant ilmenite, apatite, titano-magnetite and feldspar mineralisation are present in a weathered horizon up to 25 m thick. After several drilling campaigns in the Crater and subsequent feasibility studies, the project was developed by Monto Minerals Ltd, an ASX listed company, in 2007. However, the project never achieved production performance expectations and ran out of commissioning funds. The company subsequently went into voluntary administration in August 2008.In 2009, the RMM Capital group, of Brisbane, took control of Monto Resources Pty Ltd, and renamed the company Belridge Enterprises Pty Ltd (Belridge). Belridge commissioned a redevelopment study aimed at recommencing mining and processing operations. As part of the redevelopment study the authors planned a drilling campaign, managed a quality control program and developed a block model. This paper describes the drilling program, analytical procedures, quality control procedures and the preparation of the block model.The block model for the resource estimate was created using 1 m high blocks, wireframes defining the main material types, and 2.5 m thick horizontal search ellipsoids with a radial pattern. The deposit was ‘flattened’ prior to modelling. To assist with the economic evaluation of the project, each block in the model was assigned a net dollar value based on economic parameters provided by Belridge, including anticipated revenues and costs. This modelling technique allowed for efficient investigation of various scenarios and was used extensively in the development and optimisation of the project’s financial model. At a zero net value per block, comparable to a break-even cut-off grade of four per cent ilmenite equivalent, the Indicated plus Measured resource is estimated at 51 Mt, averaging 4.1 per cent ilmenite, 1.9 per cent apatite and 2.5 per cent titano-magnetite.

Oct 5, 2011

By Misra A

After review of the status of research on optirnisation of retreat longwall faces it is argued that an acceptable optimisation model must be based upon realistic cost data that take into account not only the face costs, but the total panel costs. These include the cost of development, face cost, removal and installation cost. The determined optimum length of a retreat longwall face is based upon a realistic model and actual costs.Parameters that influence the optimum face length have been varied over wide limits to allow determination of the sensitivity of the model and the effect of the parameters on the optimum face length. It is concluded that for medium production rates and medium system availability, the optimum face length of a retreat longwall face under Australian conditions lies between 180 and 220 metres.

Jan 1, 1995