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By Reeves M

A review of the literature available in English on kriging and geostatistics is given with the references cross-classified by their subject matter for convenience and ease of use.

Jan 1, 1979

In the early stages of opening up a mine, when there is some uncertainty as to its future career, necessitating caution in laying out works of a permanent character, the want is often felt of an assay furnace, easily built and easy of transportation, should the" mine " prove to be " no mine." Again, cases occur in which parties buy the right to treat comparatively small heaps of tailings, and then shift their plant to other localities. Under these circumstances it is necessary to restrict the plant to the barest necessaries, to suit, so to speak, the nomadic character of the work.An assay furnace that is really portable, easily transported, erected, taken down, of little weight, always ready for action on short notice, is indeed in these cases a desideratum which has long been wished for. The gasoline furnaces introduced intothe Australian market some time since practically fulfil these conditions; but they have the fatal drawback of being dependent on a constant supply of the liquid fuel, gasoline, which is seldom, if ever, obtainable locally in' any wayback mining township...

Jan 1, 1904

By M E. Dunphy, P Silversmith

The Reefton Goldfield, both historically and potentially, represents a significant gold producing camp in the Westland province of New Zealand. Some two million ounces of gold have been produced from the Greenland Group host rocks between 1870 and 1951 with the most significant producers being the Blackwater and Globe Progress mines.   Steep terrain, high rainfall, poor outcrop, widespread fluvio-glacial deposits, tertiary cover and sometimes onerous environmental access conditions have proved a challenge to conventional exploration techniques. In addition classic exploration techniques have come up against a desire to reduce exploration cycle time and exploration costs while increasing both quality and quantity of geological information.   The trial, and subsequent implementation, of Wacker sampling has proved a highly successful and effective geochemical tool currently being utilised to target, discover, and define potential economic gold mineralisation in the Reefton Goldfield.

Jan 1, 1997

By P L. McCarthy

In an environment of accelerating capital costs, limited capital availability and strongly cyclic metal prices, there is a difference between a robust mining and processing operation and one that would maximise shareholder returns in an idealised world. A higher cut-off grade policy is likely to improve operating margins and may reduce the scale of operations and thus limit capital exposure. This will leave some metal in the ground, but it is marginal material which carries the greatest cost and risk exposures. Where do we draw the line?CITATION:McCarthy, P L, 2013. Is bigger better? Building market resilience into process plant design, in Proceedings MetPlant 2013 , pp 66-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

For the purposes of this discussion it is assumed that contributors should express the thoughts that arise from their personal experience. So wide is the range of mineral deposits, and so varied the methods employed in their discovery and development, that no two geologists are likely to have been impressed with the same applications of their science. The author's own personal experience has been, during recent years at least, very largely concerned with the broader aspects of the employment of scientific method and geological knowledge to the problems of exploration and exploitation, for the guidance of the general public and governmental authority rather than of mine executives and directors. The view-point thus reached is likely to differ in many respects from that of men who are much more intimately concerned with the mining problems of a single metal or a single mining field, and for this reason a statement may perhaps supplement those from others whose experience has been markedly different.It may well happen that, at some not distant date in the future, when systematic and comprehensive instruction in economic geology is embodied in the courses- prescribed for mining engineers during their years of training, the author's comments will be quitesuperfluous; but at the present time they appear to him to call for expression.The Need for Training of Mining Men in Economic Geology.Contact over a period of many years with mining men who have had different kinds of training and experience has been convincing that there is a general reluctance to acquire a full rational understanding of the geological factors involved in exploratory and developmental problems. The correction of this attitude is regarded as vital to the industry and it is necessary to insist that the outstanding requirement of the present day is the utilization of all branches of geological, investigation in the field and the laboratoryby men who have had systematic and specialized training in these matters. The science of geology is many-sided, but is, nevertheless, whole and essentially indivisible. No one can afford to disregard any fraction of its content 'or any of its methods of investigation.The greatest advances have been made in the understarnding of the occurrence of mineral deposits by those whose knowledge Qfbasal principles, has been soundest, whose endeavour has been to ascertain all their relationships in space and time, whose attention to detail of all kinds has been keenest, and at the same time, whose capability to distinguish between major and minor features has been most marked.With the passage of the years and the accumulation of data from many lands, it has been possible to build up a great body of information regarding the primary deposition and secondary alteration of mineral occurrences, which is of the utmost value in guiding thesearch for new deposits to take the place of those that become exhausted. This heritage is due not only to the efforts of gifted in...

Jan 1, 1950

By K Firmin

The Mt Tom Price orebody of Hamersley Iron Pty Limited consists of a folded hematite - shale sequence capped by a layer of goethite. Consequently, variations in iron content occur within the ore body, and as the overall grade is below that required to make specification products, selective mining must be carried out. A necessary preliminary to quality control of products based on selective mining is the production of advance data on the tonnages and grades of material to be expected in future mining areas. Bench plans showing zones of different grades and types of material anticipated are prepared from structural geological information. The grades of materials on a bench are essentially governed by the positions and attitudes of the shale bands. Quality control is exercised by blending different grades and types of material in primary crusher feed. Iron grade is the prime grade consideration although sometimes the level of phosphorus content must be considered. Pre-production grades are determined from assay of samples taken from blast hole cuttings. As shales are more friable than hematite, product fines are always lower in iron grade than the lump product. The realisation of contract specification grade is more difficult with fines than with lump, so maintaining the correct fines grade becomes a prime factor in quality control. Control of fines grade is presently effected by aiming for an appropriate feed grade to the primary stockpile. Studies to estimate fines grade directly by qualitatively taking into account material types are in progress. Quality control measures are checked by monitoring the crushing and screening plant output, and taking appropriate compensatory actions in the mine when required. Minor fluctuations in quality of fines can be blended out on stockpiles. The quality control measures described ensure constant quality products, and a good recovery of high grade material from the deposit.

Jan 1, 1971

The closure of the only professional mining school in New Zealand will mean that the minerals industry will have to explore other options to fill their mining professional positions. Globally mining is not seen as an attractive career option for young people and recruitment into mining courses is at a low level. Yet industry demands ever increasing competencies with respect to technology, environmental issues and legislation. This paper addresses this issue by first discussing the attributes required of graduate mining professionals. It then looks at alternative ways on how these can be met internationally and on the home front.

Jan 1, 1997

By M A. Mongillo

Most geophysical and geochemical data collected during regional exploration programmes are in vector form (location, value), and have traditionally been presented and interpreted in a profile or contour map format. However, the human vision system can interpret data presented in image format much more easily and new information is often revealed by the judicious application of powerful interactive computer image enhancement techniques. This paper describes a practical demonstration of the application of such tools to gravity and resistivity datasets from the Central Volcanic Region of theNorth Island.   Filtering, contrast enhancement, relief shading, pseudo-colouring and then overlaying of the gridded datasets in image format has helped identify inter-relationships such as the association between many low resistivity anomalies (epithermal deposits or geothermal resources) and the edges of large gravity anomalies (calderas or grabens). Similar revelations should result from the application of these tools to the integration of other mapped datasets from geophysical, geochemical and geological disciplines.

Jan 1, 1992

By S Worden, A Lee Zhi Yi, E Sellers, G Corder, A Littleboy

The global shift towards decarbonisation is driving competition for the extraction of critical minerals such as nickel, lithium, and copper. To meet this demand, new mines are being developed while mines approaching closure are being reimagined as sites of potential resources. This reimagining challenges how mine closure is being conceptualised. In the conventional case, when a mine reaches the end of its economic life, it is closed or put into care and maintenance until it transitions to the next land use, such as agriculture, native ecosystem corridors, solar farms or integrated eco – precincts (Murphy et al, 2019; Holcombe, 2020) (the authors acknowledge that unplanned mine closures have left a devastating legacy of contamination, safety and cultural heritage impacts). Extracting minerals from closed or closing mines will extend mine life and, therefore, delay relinquishment and transition. In this context, innovative technologies are needed to make mining economically viable. In the first year of her doctoral research on improving stakeholder engagement in mine transitions, Lee Zhi Yi has coined the term ‘mine life extension technologies’ (MLETs) to describe a class of technological solutions that optimise extraction of resources after a mine reaches the end of its economic life. Examples of MLETs include agromining (van der Ent et al, 2015), in situ recovery (Robinson and Kuhar, 2018), and reprocessing or reuse of tailings (Gou, Zhou and Then, 2019). MLET extraction offers several benefits compared with conventional mining processes, such as waste remediation, value recovery of minerals, a smaller footprint and less environmental impacts (Sellers, Picorelli and Salmi, 2022). What requires further investigation is the consequences of MLET implementation to host communities or community perspectives towards the proposed technology and subsequent delays in transition.

Aug 2, 2023

The geological features of the destructive plate margins of the southwest Pacific favour the formation of porphyry type deposits. The major controlling factor favouring the formation of gold-rich deposits of this type is a dense crust. This results in shallow intrusion of large magma bodies beneath andesite stratovolcanoes. Where the intrusives have near vertical sides, the comparatively low temperature of transfer of volatiles from the solidifying melt favours the partitioning of gold into bubbles of volatiles. They reduce the viscosity and density of the melt, resulting in the upward movement of a mineralised melt. With the drop of pressure with upward movement the bubbles separate into a two phase mixture, triggering freezing of the mineralised melt and the formation of a gold mineralised stockwork.

Jan 1, 1995

By D Craw

Bulk ore tailings from the Macraes gold mine gold extraction process are stored in a large (ca 0.6 km2, 80 m deep) mixed tailings impoundment whose pH is maintained near 8 by natural rock neutralizing capacity. The mixed tailings will be stored in this impoundment in perpetuity after mining ceases. Confidence in the long term environmental stability of these tailings can be gained from examination of mineralogically and chemically similar geological situations in the immediate vicinity. A sequence, typically about 5 m thick, of sands and gravels derived from the Macraes mineralized zone 12 000 to 28 000 years ago contains rounded detrital sulphide mineral grains which are unoxidized despite close proximity to the surface and occasional incursion of oxygenated waters. Saturating water pH is currently 7-8. Sands with 0.2 to 0.8 wt % organic carbon host sulphate-reducing bacteria (SRB), and localized cementation by authigenic framboidal pyrite has occurred. Comparison of the 28 000 year-old sediments with the modem tailings suggests that similar chemistry will prevail, possibly with deposition of authigenic pyrite in the tailings, in the long term. As long as the present slightly anoxic and circumneutral pH environmental conditions are maintained in the mixed tailings dam, sulphide decomposition and acidification are unlikely. These sediments provide a plausible geological analogue for long-term benign storage of the mixed tailings impoundment.

Jan 1, 2000

By Whiten W. J

A simulation model was used to study the performance of various types of screen cloth on industrial vibrating screens. The model takes into account the effect of loading upon screen performance and predicts both themass flow rate and size distribution of the screen products.It was found that the use of the simulation model allowed the reconstruction of data for identical conditions and hence has simplified the analysis of the comparative performance of the screens. The dependence of performance upon operating conditions was found to vary markedly with screen cloth type.

Jan 1, 1977

By N Cusworth

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines û mining, metallurgical, chemical, civil, electrical, mechanical and environmental û as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies û and hence no two development projects û are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource projectÆs development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as ædoing a feasibility studyÆ. But the principal purpose of a æfeasibility studyÆ is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant û they are a prerequisite to the demonstration of a projectÆs viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of æfeasibility studiesÆ and provide guidance to minimum standards and best practice.

Jan 1, 2007

Leading Article from "British Medical Journal," London, 4th, November, 1944.Assuming that silica exerts its injurious effect upon animal tissue through a slow transformation into silicic acid, Denny, Robson, and Irwin thought that if the solubility of siliceous material retained in the lungs could be suffciently reduced the usual fibrotic response could be diminished or prevented. They discovered that aluminum powder rendered siliceous material insoluble in vitro by coating the silica particle with a thin film of gelatinous hydrated alumina, which on drying formed crystalline alpha aluminum monohydrate. The presence of this adsorbed layer on the surface of the quartz was shown by staining it with aurin. That metallic aluminum dust produced no fibrosis in the lungs was demonstrated by dust-inhalation experiments on eight rabbits. Attempts were therefore made to prevent silicosis by mixing quartz with metallic aluminum dust.Animals exposed to quartz dust developed typical silicosis in about five months, but the addition of 1 per cent. aluminum powder prevented this even after exposure had been lengthened up to 22 months, provided the aluminum powder was of a particle size below 5. This year Crombie, Blaisdell and MacPherson have reported the treatment of 34 silicotic miners by the daily inhalation of fine aluminum powder freshly ground from small aluminum pellets in a specially constructed mill. Daily treatment began with five-minute inhalations, which were gradually increased to 30 minutes. Some of the men received 300 treatments, but the majority only 200. Out of the 34 cases thus treated clinical improvement was manifested by lessening or disappearance of shortness of breath, of cough, of pain in the chest, and of fatigue. In 15 cases the condition became stationary and remained so in spite of continuous employment in silica dust throughout the treatment. The progress of the disease was assessed by means of tests for respiratory function repeated at three-monthly intervals. Obviously this treatment cannot be regarded as a cure for silicosis, since it cannot restore lung tissue which has undergone fibrotic change; but Crombie and his colleagues believe that the inhalation of finely particulate aluminum powder offers every prospect of preventing the development of human silicosis.In view of these findings, it is surprising that repeated papers by Goralewski from Germany describe various types of lung disease attributed to aluminum dust, and press for them to be scheduled under the Workmen's Compensation Act in that country. Seven hundred workers were investigated. They were making, probably by a stamping process, aluminium powder containing about four milliards of particles of dust per grain, and are reported as complaining of dry cough with pain on breathing, shortness of breath, poor appetite, and gnawing abdominal pain. Spontaneous pneumothorax developed in four workers. No abnormal physical...

Jan 1, 1945

The Framework Convention on Climate Change (FCCC) places serious obligations on New Zealand as a signatory nation. This paper examines the nature of the FCCC, New Zealand 's proposed policy response, and the.implications for the minerals industry.

Jan 1, 1994

By P Allen, E Gleeson, D Boakye, R Chesher, S Konopa

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Not only do epithermal gold deposits provide many challenges in estimating mineral resources, the complexities of these deposits also provide technical challenges in assessing appropriate mining and processing strategies, as well as social and environmental planning and management. The characteristics of epithermal gold deposits include being highly variable with respect to geometry and gold grade distribution, the presence of other economic contributors, mineralogy, texture, rock strength, weathering and alteration overprint. These characteristics influence the economic value of mining projects in an interlinked manner. Consequently, successful exploitation of epithermal deposits requires a holistic approach, coupled with the effective integration of geological data to meet all aspects of mine development decision-making. This paper presents examples of the key technical challenges encountered in estimating and mining epithermal deposits. It also highlights why these issues need to be addressed from the viewpoint of geology, sampling, resource estimation, mine planning, mineral processing and social and environmental planning for the true value of the mining project to be realised.CITATION:Konopa, S, Chesher, R, Gleeson, E, Allen, P and Boakye, D, 2015. Challenges in maximising the value from epithermal gold deposits, in Proceedings PACRIM 2015 Congress, pp 127–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

FREQUENTLY the Survey Department is caIled upon to estimate the quantity of material in various dumps, dams piles, etc... and in the carrying out of this work various methods may be employed.The method used will vary according to the particular case in hand, and factors such as accessibility of the top of the dump, steepness of its sides, height, and the condition of the material to be estimated. A certain amount of "give and take" must be adopted in the treatment of small local cavities and mounds.In all cases it is desirable that the surveys made should be tied on to the lease surveys for the purpose of location, and that all levels should be reduced to the mine datum. It is also desirable to obtain levels of the original surface before deposition of the material to be estimated. If these have not been obtained beforehand, levels and transfers round the top will be the next best. If space is availabIe, flat surface is chosen as a site for the dump, etc. This is of the utmost importance in those cases where the material will have to be...

Jan 1, 1925

The problems of using comparatively simple x-ray diffraction equipment for quantitative analysis are examined. Internal standard and direct calibration procedures based upon the measurement of integrated diffraction energy (diffractometer peak area) have been developed for the determination of quartz in Broken Hill dusts. By these methods an accuracy of ± 10 per cent of the true value can be obtained and this can be improved to ±2 1/2 per cent by statistical methods if necessary.Rapid analysis for the components quartz, muscovite, rhodonite, galena, fluorite, sphalerite, calcite, and garnet has been developed by adaptation of direct calibration procedures and use of maximum diffraction energies (diffractometer peak height). Until more is know!) about the pathological effects of multi-component dusts of the Broken Hill type it seems undesirable to fix theIr allowable concentrations in terms of the quartz content.

Jan 1, 1968

By Honeycombe R. W K, Greenwood J. N

Powder metallurgy has been developed rapidly in the last twenty years by overseas metallurgists. The technique of making the powders and their subsequent pressing and sintering into useful forms has' only been introduced into Australia under the stress of war-time economic conditions.The technique involved has very little in common with our usual methods of fabricating engineering alloys by melting the ingredients to a homogeneous mass, followed by casting to shape or casting to ingot form and shaping by application of pressure-so-called mechanical working. On the other hand, the technique includes operations, such as milling and sizing, familiar to the primary metallurgists.The compacting of metal or other powders finds important application in two outstanding fields of engineering production: (a) in making porous bearings and contact brushes, in which such a material as powdered graphite can be incorporated; (b) in making cutting tool tips of hard -carbides, which have a melting point too high to make casting feasible, and which would be too brittle in the cast condition in any case. In both these cases; the final article can be made of the desired shape and size (subject to shrinkage allowances) whilst the compact is in a soft and readily machined condition a consideration of great importance in connection with the hard carbides.In order to develop the necessary equipment and technique and at the same time to assisil in the war effort, it was decided to divert the research work of the Metallurgy Department of the University of Melbourne to the problems associated with the production of hard carbides from local raw materials and the sintering of such into tips for cutting tools. Since this work was started at least two industrial concerns have started to produce these materials in the Commonwealth.The work. to date has included (a) the purification of crude cobalt oxide from Risdon and the reduction of this to metal Particles of less than 10 p. diameter; (b) the production of tungsten powder from King Island scheelite and its conversion into tungsten carbide with particle size less than 4 p. diameter; (c) the sintering of the latter product, using the former as a bond; (d) the production of titanium carbide from titanium dioxide; (e) the separation of columbium and tantalum oxides from a Northern Territory tantalite, and the conversion of these into the respective carbides.

Jan 1, 1942

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