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Using a Jarrell-Ash "Compact" direct reading spectrometer, analyses were made of a wide variety of rocks ranging from acidic to ultrabasic types. Statistical evaluation suggests that accuracies comparable with the values obtained by the rapid chemical methods used by the United States Geological Survey will be obtained.The spectrographic method involves fusion of the rock with lithium tetraborate, strontium being incorporated in the flux as the internal standard. The resulting bead is ground with graphite and pressed into a pellet. The counts obtained on two standard pellets are used to correct for instrumental drift.Background readings are made at 4109 Å and corrections for background are made to all lines. Corrections for matrix interferences, both by chemical suppression and optical enhancement, are made. The three corrections of drift, background, and matrix are incorporated into one general expression which has been programmed on magnetic cards, each element requiring a separate card. The cards are placed individually into a desk top computer (an Olivetti Programma 101), which enables true counts to be calculated from the "readout" counts, and the element concentration is then obtained from computer-printed tables by referring to the appropriate value of true counts versus concentration. These tables were prepared by making a polynomial regression analysis of the spectrographic results from 50 standard and analysed samples, a curve of best fit being chosen for each element.The regression coefficients, usually of a fourth or fifth degree equation, together with other relevant data, were fed into a large computer, programmed to print out tables of concentration versus true counts. This technique enables the results obtained to be based on mathematically-derived values rather than on hand-drawn calibration graphs, giving greater inherent accuracy. The technique has been shown to give results of good accuracy and acceptable precision suitable for many geological and geochemical exploration programmes involving the analysis of many rock samples of different types.

Jan 1, 1969

The earth is a planet limited in size and limited in total resources. For the forseeable future, it is the only available habitat for mankind. Therefore, it follows that the more we know about our planet the better we can utilize its space and its resources for our well-being now and in the future. But, to accomplish this, we need reliable basic information. Geosciences provide such information. Recently, Dr. M. King Hubbert took note of the important effect of the geosciences on society, on how we think, and how we live. In the first century of modern geology, 1780- 1880, the influence of geology was primarily on how we think, i.e. changing our concept of the earth from one with a short catastrophic history to one that developed gradually over enormous spans of time. In the second century, 1880-1980, the emphasis was on how we live, on expanding the knowledge base so that we could more easily find and utilize the earth's resources. Now, in the third century, i.e. from 1980 towards the year 2000 and beyond, we should concentrate on both how we think and how we live; i.e. how we can better estimate potential global' resources and how we can manage these resources for maximum benefit to mankind. Like other sciences, the geosciences build upon what has already been done. Progress is achieved by using the thoughts, measurements, and observations of past workers, adding to these the insights from new experiments and from new concepts. Geology has its own methodology and approaches; but more than most sciences, it calls also upon the tools of physics, chemistry, mathematics, engineering, and biology to help solve its problems. Today's increasing population, increasing industrialization, and increasing complexity of modern society demand more detailed geoscience information so as to better use the land, reduce geological hazards, provide an inventory of resources, facilitate waste disposal, and prepare for long-term effects such as changes in climate and sea level.

Jan 1, 1986

Many operating hard-rock sulfide mines are predicted to require perpetual post-closure management to prevent environmental degradation. Causes include evaporative concentration of metals and other solutes in pit lakes, and acid rock drainage from sulfide waste-rock, tailings, and pit benches. Dilemmas posed by the prospect of perpetual management include: uncertainty in predictive models typically prevents reliable bounding on forecasts for the timing or magnitude of environmental impacts; comprehensive closure designs that can meet environmental standards may not be economically possible, particularly when applied retroactively to mines permitted under less stringent closure requirements; the publication of site-specific environmental analyses in peer-reviewed journals are discouraged in the current regulatory environment, hindering scientific advancement; and the durability of financial and government institutions cannot be assured for the long-time horizons over which mine impacts are predicted to occur. Re-evaluating mine closure in a framework of sustainable development (as proposed by the Mining Mineral Sustainable Development forum), can resolve, in part, these dilemmas. Key sustainability goals include: assurance of the social and economic well-being of the local community; assurance of the long-term environmental integrity of the region; and establishment of institutions capable of addressing (and learning from) long-term environmental management. Under a sustainability framework, impractical plans for immediate attainment of perpetually-stable closure may be replaced with a fund for long-term management of environmental impacts (eg through contaminant migration controls and exposure barriers), and a set-aside long-term growth reserve intended to eventually fund more complete closure. Fund expenditures would follow Adaptive Managementùa template for environmental-management institutions in which knowledge accumulated and uncertainty acknowledged explicitly. Under adaptive management, trusts would be flexible entities, supporting an evolving program of monitoring, predictive model refinement, and treatment. Periodic value of information analyses would target data collection efforts, refining the balance between predictable cost and uncertainty. This framework could overcome present-day financial shortcomings, enhance the field of environmental science, and meet the needs of future generations through the propagation of capita.

Jan 1, 2003

By G, F Beach, D Jazzini, R Rounsley

Over the past 20 years within Australia, there have been a number of incidents at mine sites where ammonium nitrate-based explosives have reacted with certain rock types containing sulfide minerals. These rocks have commonly been referred to as æreactive groundÆ. These reactions have frequently led to fires (particularly in ground susceptible to spontaneous combustion) or premature detonation of the ammonium nitrate-based explosives. Clearly, this introduces an element of risk when using ammonium nitrate-based explosives in these areas. Dyno Nobel has been proactive in developing ammonium nitrate-based explosive products that can be used in these types of æreactive groundÆ environments that minimise the risk of premature detonations occurring. A system for assessing æreactivityÆ of sulfide containing rocks has been developed that can be used in the field. Previous literature has been reviewed, identifying Differential Thermal Analysis (DTA) as the most common method for determining the æreactivityÆ of the ground. In the present investigation, DTA has been rejected as a suitable technique for determining ground reactivity, since it measures thermal reactions at higher temperatures over short time periods, conditions that are unlike those in the field. For example, ground at ambient temperature has been found to react with ammonium nitrate-based explosives over long time periods, reactions that are unable to be evaluated using DTA. Other more suitable techniques have been developed to monitor rock conditions that can be measured in the field and give a good indication of potential ground æreactivityÆ with ammonium nitrate-based explosives. Dyno Nobel is currently investigating the reaction mechanisms of spontaneous combustion in reactive ground, the decomposition mechanisms of ammonium nitrate and the role of inhibitors in ammonium nitrate-based explosives. Once complete, this fundamental research will lead to the further development of even lower risk ammonium nitrate-based explosive products for use in æreactive groundsÆ in a variety of mine environments.

Jan 1, 2003

This paper summarises the performance of the gold exploration industry in the Western World since 1970, with particular emphasis on the period 1985 - 2003. It identifies the number and size of major (ie >1 million ounce) primary gold discoveries made over this period by location and type of company. Estimates are also made of the likely contribution from smaller discoveries down to 0.1 million ounces. It also assesses the overall trend in the percentage of grassroot discoveries that are converted into mines, and the time taken to get them into production. By comparing the discovery data against total exploration expenditures it is possible to determine the average unit cost of finding a major gold deposit. It is significant to note that the average unit cost per discovery and per ounce of resource has tripled over the last 30 years. An attempt is made to determine the overall economic value generated by the industry. This is based on a detailed analysis of the rates of return and the Net Present Values (NPVs) of 109 major gold projects. After including an adjustment for discoveries not modelled, the NPVs are compared against the total amount of money spent on exploration to determine the value-to-cost ratio for the industry. Based on historical spot gold prices and tax rules, it is found that the return on investment for gold exploration in the Western World over the period 1985 - 2003 was around five per cent real after-tax. The returns achieved in the US and Australia was significantly higher than that for Canada. The returns also appear to have declined in recent years. With regard to the relative performance of junior versus major companies, the paper estimates that the junior sector accounted for 30 - 40 per cent of the total exploration expenditure, and were was associated with 34 per cent of the total number of major deposits, 27 per cent of the contained ounces and 25 per cent of the economic value found.

Jan 1, 2004

The recovery of Copper by solvent extraction was arguably the most significant hydrometallurgical development of the 1960's. However, only dilute solutions at relatively high ph. could be treated effectively. ICVAcorga introduced in the 1970's the much stronger salicylaldoxime based reagents, which resulted in a dramatic change in plant configurations. So for example plants which normally use 3 extraction stages and 3 stripping stages could be reduced to 2 + 2 staging or 2 + 1 staging, even for high copper tenors at low ph. Leach liquors up to 40 g A copper are being treated at some locations so that almost any copper bearing liquor can now be purified by solvent extraction. Following a considerable amount of research and development effort ICI/Acorga have made further significant advances in the application of copper solvent extraction. The first of these is in computerised flowsheeting. In conjunction with ICI's Process Technology Department, Acorga have developed the Minchem Computer program, which uses laboratory generated equilibrium data to facilitate optimisation of metallurgical operating parameters. The program can operate in two modes, prediction and assessment so that given suitable extract and strip isotherms plant performance can be predicted for a given set of conditions. Alternatively existing plant performance can be assessed rapidly and accurately, thus providing a valuable quality control tool. Pilot plant work can now be restricted to evaluation of the physical aspects of the SX circuits, and to looking for the unexpected. Secondly using the patented 5-Nonyl Salicylaldoxime in precise admixture with a number of carefully selected strip modifiers, the Acorga M-range has resulted. Reagent selection from these new extractants can now be based on how the reagent can alleviate the remaining problems such as hydrolytic stability, transfer of iron, and organic losses by entrainment which may be related to particular features of the operating plant. Thus the Acorga M-range has enhanced and significantly extended the use of solvent extraction for copper, whilst refinements in the processing of metallurgical data has considerably simplified circuit design and analysis of results.

Jan 1, 1989

By G Newling

Zinifex Rosebery Mine is a lead-zinc underground mining operation located at the base of Mount Black, on the West Coast of Tasmania. Mining activities at the Rosebery Mine have been undertaken for over 100 years, and it has been operating in its current form for over 60 years. A large surface and underground exploration drilling program over the last 18 months has increased the mineÆs expected mine life from five to 12 years, with expectations that over the next 18 months as the program continues this will swell to 20 plus years. Zinifex Ltd secured Rosebery Mine in April 2004 and commissioned a detailed life-of-mine (LOM) study on all aspects of the operation. One of the most detailed sections of this report was on the state of the current ventilation system. It was identified in this report that for mining at the current depth of approximately 1100 m to continue a minimum 30 per cent increase in ventilation quantity was essential, as well as a likely requirement for a refrigerant cooling plant for each of the two deepest panels, the K and P lenses. It was identified that Zinifex did not have personnel with the expertise in underground refrigeration to manage and implement a project of this nature. A second report was commissioned with Bluhm Burton Engineering (BBE), a South African firm specialising in both surface and underground large-scale refrigeration plants. BBE concluded that two refrigeration plants were required to provide the necessary cooling power in the lower sections of the mine. In 2005, with BBE as technical consultants, Zinifex Rosebery Mine embarked on a project to commission two underground refrigeration units capable of lowering the wet bulb temperature at the decline face by four degrees centigrade. This paper is intended to give the reader an overview of: Rosebery Mine operations,Rosebery underground refrigeration project,technical difficulties associated with implementing an underground refrigeration system, andkey learnings to date.

Jan 1, 2008

By R Williams, P Godwin

In a time of changing rainfall patterns and in the light of recent tailings dam failures, there is closer environmental scrutiny for proposed tailings dam construction or expansion. Therefore the elimination of the traditional tailings dam could provide both environmental and cost benefits to an operation. One method to dewater tails is using pressure filtration to achieve lower moistures than what is currently available using other dewatering technologies. Further benefits include a higher rate of filtrate recovery, reuse of waste material and the potential for dry stacking of the filtered tailings cake, thereby minimising both risk and cost. This paper chronicles the replacement of two existing belt filter presses with a single McLanahan recessed plate filter press to dewater a tailings stream at a Bacchus Marsh site. It covers the slurry testing, equipment selection, installation, commissioning and operation of the filter press to achieve the following objectives:• removing the current tailings dam and slimes cells from the existing process to minimise failure risk and reduce the cost of a dam upgrade, as well as operational and maintenance costs• free up the surface area which was previously occupied by tailings dams and slimes cells• recover additional water to be returned to the process• reduce flocculent usage• reduce truck movements and handling.The project’s owner also expects to reduce carbon emissions by over 3000 t over the lifetime of operation as well as substantially reducing operating expenditure. By recognising the carbon reduction benefits, the project owner was able to successfully achieve partial funding through the Voluntary Waste Industry Protocol.An unanticipated, but as yet unquantifiable, bonus for the project was to seek an offtake agreement for the tailings thereby allowing the tailings to be considered a valuable source of beneficiated clay suitable for the construction industry.CITATION:Godwin, P and Williams, R, 2017. Pressure filtered tailings – environmental and cost benefits, in Proceedings MetPlant 2017, pp 324–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Mozley R

Contaminated sediments are a multinational problem. A crucial factor in solving an environmental problem is knowledge of, not only the amounts of polluted soil, the contaminants involved and their concentration, but also the historical background of the problem. Processing polluted soil is a tailor made activity based on rational decisions resulting from a detailed treatability study. Lack of information about characteristic properties of a specific sludge/pollution combination is the main obstacle in the route from first ascertaining that a particular harbour subsoil is polluted, to final identification of the full scale treatment plant. In the first instance, information must be generated regarding the distribution of pollutants in relation to the distribution of the original geophysical components. Based on this information rational decisions can be made on separation at a particular cutpoint and what sequential techniques should be involved for a certain fraction. For this purpose a `fingerprint method' is presented especially developed for investigation of polluted soil and sediments. The heart of the fingerprint method is a series of sequential hydrocyclone separations, by which a series of products is generated. The objective of the fingerprint method is to select an optimised treatment procedure in which the pollutants are concentrated in as small a volume of material as possible, leaving the bulk of the material clean. The pollutants can then readily be destroyed or isolated from the environment. The philosophy and advantages of the fingerprint method are demonstrated for a harbour sludge containing heavy metals as main pollutants. Hydrocyclone separation combined with flotation of both the coarse and fine fraction resulted in reusable and dischargeable products. Flotation of the fraction of fines was carried out by means of an experimental flotation cyclone enabling the selective recovery of mineral particles with diameters less than 10 microns. The overall conclusion is that design and engineering of treatment flow schemes for polluted dredged materials is a tailor made activity based on rational decisions resulting from the fingerprint information.

Jan 1, 1993

By D P. Obeng, L Reemeyer, R Holmes

The Zinifex Century Mine employs a large number of Detritor mills for fine and ultra-fine grinding to liberate silica and sphalerite at 80 per cent passing 7.5 microns before final zinc flotation. A joint project between CSIRO Minerals and the Zinifex Century Mine was carried out to evaluate the Detritor mill performance. Plant surveys were conducted around the Detritors in conjunction with laboratory tests. The survey data showed that the Detritors in the ultra-fine milling circuit performed well. They reduced a feed F80 sizing of 46 microns to a product P80 sizing of 7.5 microns at a gross energy consumption of 37.2 kWh/t. Scale-up of ultra-fine milling Detritors was studied using a 0.55 kW laboratory batch unit and a 355 kW full-scale Detritor by processing Century zinc concentrate with 1 mm sand media. The results indicated that the 0.55 kW laboratory mill underestimated the energy consumption of the full-scale Detritor by about 20 per cent for a product P80 of seven microns. The performances of a horizontal IsaMill and a vertical Detritor were compared as ultra-fine milling devices for processing Century zinc concentrate. The experimental data demonstrated that, when using the same grinding media, the energy efficiency of the two mills is similar despite the difference in mill designs. The Detritors used for regrind duty at the Century Mine performed poorly when processing feed at 80 per cent passing 88 micron. The energy consumption was high and the product size distribution was broad with particles above 100 microns in the feed unbroken and particles below ten microns overground. A coarser ceramic media of 3 mm was therefore tested in a laboratory Detritor to process the regrind Detritor feed as an alternative to the 1 mm Colorado sand used at the Century Mine. The ceramic media reduced the energy consumption significantly and produced a narrower product size distribution, which is more desirable for the downstream flotation process.

Jan 1, 2007

By J Moncrieff, P Bellairs

The Black Star Open Cut is located immediately adjacent to the township of Mt Isa and is situated in the middle of extensive pre-existing infrastructure including two concentrators, two smelters, a wet fill plant and two shafts. At any one time there are in excess of 500 people working on the surface within an industry-accepted 600 m exclusion zone from Black Star blasts. Apart from the surface operations there are also the underground operations including the lead mine (closed in December 2005) and the Enterprise and X-41 mines that must clear for all Black Star blasts. The application of industry standard blasting exclusion zones (600 m) was risk assessed as imposing operationally prohibitive constraints which could cause significant business interruption due to the logistical challenges required to ensure that all personnel from surface plants were evacuated for each blast and potential for lost production whilst these personnel were not operating the plant. In was therefore an imperative for the blast exclusion zone to be reduced. This was achieved by the: use of a QA/QC team to ensure that relevant drill and blast implementation is within an acceptable tolerance (KPIs) from design; use of high-quality stemming material called HMR, which is a by- product of the concentrating process and is generally sized at -14 mm with very little fines; implementation of appropriate training and support to Black StarÆs own blast crews, reinforcing the need to achieve the designed amount of stemming in every hole; and provision of appropriate support from Black StarÆs management for additional resources to ensure that every blast achieves design within the KPIs but especially in high-risk areas. The blast exclusion zone was successfully reduced after monitoring the flyrock results from more than 176 blasts. Black Star Open Cut now maintains a minimum blast exclusion of 200 m in critical areas; however, general blasting currently uses a 250 m exclusion as this provides additional risk management whilst still minimising the logistics associated with clearing and securing the slightly increased area.

Jan 1, 2007

The scope of this paper has been restricted to the manufacture in Australia of seamless steel tubing, as the subject of buttweld tubing has already been dealt with by A. N. Hamilton in a paper delivered before the Institute in 1935.The earliest attempts to produce seamless steel tubes were based on the extrusion of lead piping, a process developed by Thomas Burr in 1820. However, the problems associated with the extrusion of white hot steel had to await the metallurgical knowledge of the twentieth century, and these early attempts were unsuccessful.The years 1840 and 1845 were noteworthy for the introduction of the first practical methods of making seamless steel tubes. In one process, a large circular plate was 'cupped' in a vertical press; in the other, a round steel billet was pierced for its entire length.The product from both these methods was then elongated by repeated reheating and rolling over an internal mandrel, in a circular pass mill.At this juncture, it should be noted that every process developed for the manufacture of seamless steel tubing can be divided into two parts. In the first part of the process, attention is centred on the conversion of the heated bloom into a short, thick-walled, hollow cylindrical forging; this product is then elongated in the second section of the process. It will be noted that these two sections are actually quite distinct, and in practice numerous methods exist for carrying out both functions. The first stage is generally referred to as 'piercing', the second stage being termed 'elongating.' In this paper, the author proposes to outline the various methods adopted for piercing and elongating; the reader is asked to note that although certain methods of piercing are almost invariably associated with only one method of elongating, the distinction between the two functions is, nevertheless, a vital one and should be noted accordingly.

Jan 1, 1947

I feel a little like the Parson delivering his Sunday Sermon, chastizing his parishioners for not coming to Church. Those who need to hear me are absent.Nevertheless, I hope that if you agree with what I am about to say you will go forth and spread the word.We often hear of the impact mining has on the community. I prefer tonight to deal with the impact some community attitudes have on mining, and I want to point out that the results of these attitudes rebound to the detriment of our society. I want to deal particularly with regulation, taxation, and proflts.In a civilization whose standard of living is essentially dependent on an adequate and reliable supply of cheap metals and fuels, it should be evident to Blind Freddie that mining must be encouraged.I must express concern at the constraints inflicted on the mining industry by our community. We tend to blame Government for our difficulties, but we must recognize that Government acts merely as agent for the community. It is fair to say that in a free society, if Government actions do not reflect the demands of the electorate, then it doesn't stay the Government. It is important though for Government, in framing its policies, to ensure that it is not unduly influenced by the loud voices of minority groups.The people of our nation have every right to demand that our industry meet certain criteria to be allowed to operate. We all wish to live in a healthy and congenial environment, and to have our individual comforts protected. It is essential, however, that the community realizes that its demands on the mining industry are affecting Australia's prosperity.Each new regulation and each new tax or impost has its effect on investment, employment, and national revenue. Restraints result in an increase in costs which in turn raises the minimum value of a mineral deposit which is economically mineable. It results in minerals, which could be mined under more favourable circumstances, remaining in the ground, perhaps lost for ever.

Jan 1, 1978

By Sutherland R. A, Rawling K. R

The Nanisivik Mine is located 750 km north of the Arctic Circle at the north end of Baffin Island in the Canadian High Arctic, and has been in production since 1976. The paper describes the regional and local geology and the current mining and mineral processing operations, including recent innovations in each area. The Nanisivik zinc-lead deposits comprise Mississippi Valley type sulphides in a block-faulted sediment sequence of Proterozoic age. The deposits formed in two mineralizing stages by replacement of the carbonate host rock. Exploration techniques adapted to the permafrost environment include high frequency EM and ground probing radar. Core drilling is done with calcium chloride brine but trials with heated flushing water indicate potential for cost reduction. The predominant mining method at Nanisivik is room and pillar. Cut and fill is used in some satellites to the main zone. Due to the permafrost, dry drilling is employed in the underground mining. The permafrost enhances ground stability, permitting large underground openings and, as a result, the use of relatively large scale mining equipment. For power conservation, a remote control system for the ventilation fans has reduced mine power costs. The milling of the simple coarse-grained ore in an arctic environment requires special techniques in the design and operation of the plant for materials handling, utilisation of waste heat, reagent selection and tailings disposal. Regulated heavy metal contents in effluents discharged to the sensitive environment are achieved by natural processes. A recent change from sub-aqueous disposal of tailings to beach type deposition within a cell in the tailings area is reviewed. Planning closure of the property presents special problems and an opportunity for innovative techniques. Approximately 25 per cent of the employees at Nanisivik are drawn from the Inuit population of the Canadian Arctic. As the first permanent industrial activity in the High Arctic some innovative approaches to employee relations were required which have resulted in a very stable, culturally mixed community in a remote location.

Jan 1, 1993

The main factors which influence disposal of mine waste under New Zealand conditions are identified and discussed: namely, geological conditions which produce soft weather-sensitive waste, wet and cold winters which affect productivity in such waste, elevated seismicity which affects stability and the need for water rights which involve public participation. The waste disposal scheme for the Martha Hill Project is described, thereby illustrating how these factors influence the planning of a current mine strippings and tailings disposal scheme.

Jan 1, 1986

From March to May of 1963, the Bureau of Mineral Resources carried out an experimental aeromagnetic survey at Cobar, New South Wales, to field test a proton-precession magnetometer installation in the Cessna aircraft VH-GEO. The Cobar area was chosen as considerable information was already held on the Earth's magnetic field there, which was known to provide a range of anomalous areas that are not excessively disturbed.A procedure for survey flying and methods for processing data were developed during the survey. Contour maps of the aeromagnetic results were produced in the field. The experimental survey was successful in outlining magnetic anomalies in detail.INTRODUCTIONSince 1951 the Bureau of Mineral Resources, Geology and Geophysics (B.M.R.) has carried out an airborne magnetometer exploration programme with DC.3 aircraft carrying fluxgate magnetometer equipment. Recently a proton-precession magnetometer was developed by the Design and Development Group of the B.M.R. for observatory use. One unit modified for airborne use was installed in the Cessna light aircraft, VH-GEO. The Cessna was modified structurally to take the magnetometer, associated bird, and winch gear.The proton-precession magnetometer has many good features.1. It utilises the transistor and associated solid-state devices in its electronics, and hence is light and small.This is the basic feature allowing its installation in a light aircraft. The transistor circuits have a high reliability factor and owing to the card sub-unit...

Jan 1, 1964

By C Moorhead

The classification of Mineral Resource estimates for reporting in accordance with the JORC Code is a statement of the Competent PersonÆs confidence in the estimate and an attempt to convey that confidence to the various users of the resource estimate. In general the classification process is either largely subjective, relying on the Competent PersonÆs experience, or relies on statistical measures derived from the estimation process. These statistical measures may not necessarily relate to the overall confidence in the resource which must also take account of the confidence in the geological inputs to the estimation. Several authors, including Jackson et al (2003) and Dominy, Noppe and Annels (2004), have addressed methods of including consideration of geological data and its reliability into the classification process. Henry and Parker (2005) have discussed a quantitative measure for classification of Measured and Indicated Resources related to mine production parcels. These methods rely on the availability of sufficient information for the application of geostatistics, data evaluation techniques or repeated interpretation of data to provide an indication of confidence. They are suitable for very advanced projects. In 2005, using a modification of the financial audit æcontrol and quality criteriaÆ principles, then widely accepted within Newcrest Mining Limited (Newcrest), the principal author developed a scheme which categorised the classified resources into æcontrolÆ and æqualityÆ (or risk) categories. Control covers all aspects of the data collection, the geological interpretation, the data analysis and the modelling of tonnage and grade; it is also influenced by the documentation of the estimate. The quality criteria are a subjective measure of risk associated with the estimation of the resource and refer to the risk that the tonnage and grade are not realised and the consequences if decisions are made on the basis of these estimates. By evaluating the generally accepted level of risk attributed to these quality ratings by Competent Persons within Newcrest, a graphical representation of the confidence in the resource ounces was prepared for communication of the expected confidence in the resource statement.

Jan 1, 2009

By Branagan D. F

The geology of the area studied is briefly described, together with the prospecting methods used in the search for copper, lead, zinc and uranium ore bodies.Four prospects, Mt. Corella, Yanasinga, Lawlor's and Greenmount, which were diamond-drilled, are described in detail and geochemical results are discussed in relation to the mineralization found. Copper anomalies were found wherever intrusive rocks were mapped, and showed a much closer relation to geology and mineralization than did the predominantly lead and zinc anomalies.Geochemical prospecting aids in the overall mineral search programme because of its speed and economy, as it helps to pinpoint areas worthy of detailed geological examination. Geochemical anomalies are a guide to favourable zones but may not indicate the presence of ore.INTRODUCTIONDuring 1953-55 the National Lead Company of New York carried out a search for minerals in an area south and west of Cloncurry (Fig. 1) in rocks of Precambrian age. After reconnaissance mapping, a number of prospects were chosen for closer examination by detailed geological mapping and geochemical sampling, and from these prospects, five sites were selected for drilling.This paper records the salient features of the exploration programme and discusses the geology and geochemistry of four of the prospects-Mt. Corella, Yanasinga, Lawlor's and Greenmount. Practically all the prospects examined showed high zinc "anomalies" or "dispersion" trains. Greta, Mt. Corella and Lawlor's prospects showed some copper anomalies and, to a lesser extent, lead anomalies. In particular, Greenmount exhibited striking copper anomalies.

Jan 1, 1960

Various influences determine how an Environmental Management System (EMS) for a mining or petroleum project is developed and administered. These influences include the environmental and resource legislation applying to the project, the culture of the organisation, the environmental sensitivity of the area, and the administrative policies of the regulatory agencies involved. While financial penalties and even imprisonment may be imposed for non-compliance with environmental legislation, there are other compelling reasons for the establishment of an effective EMS. If a company wishes to be considered by Governments for the grant of exploration or mining rights, it is important that it can demonstrate environmentally responsible operations at existing facilities. The development of an effective EMS requires commitment from the Board of the company and the issue of an Environmental Policy to empower all levels of the staff and workforce to achieve environmentally responsible operations. This must be supported by the provision of appropriate human and financial resources, and environmental training of staff at all levels from the Board to the mine site, workshop and office. A regular environmental auditing programme is essential to ensure that the EMS is in place and is effective in achieving compliance with regulatory requirements, corporate policies and protection of the environment. An EMS can be developed on the basis of existing management systems, quality management systems, existing and emerging environmental management standards (such as BS7750 and ISOI4000), or sophisticated computerised systems which may incorporate international experience, standards, and codes of practice.

Jan 1, 1995

Thermodynamics of Non-Cyanide Gold Solvents The present status of the raw material base in the gold industry requires specific ways to recover gold and silver from ores. Most gold is closely associated with sulfides which require flotation followed by pressure or bacterial oxidation. The next stages of processing usually require using expensive operations for the preparation of leaching. A lot of researchers want to find a new alternative solvent for the extraction of precious metals from these products. According to the authors, one of the best ways is to use sulfur-based solvents (thiosulfate, sulfite, and their various mixtures). Thermodynamics of gold and silver thiosulfate dilution are calculated for conditions: the concentration of Au - 200 mg/L, oxygen - 3.2 mg/L, thiosulfate - 79 mg/L, OH- - 170 mg/L. the general result is the possibility of process remains under standard conditions. (erAu = = 0.035 V, ?G298 = - 29.18 kJ/g-atom ??). Silver with thiosulfate forms two strong complexes: [AgS203]- and [Ag(S203)2]3-. ?G0 = -1027 kJ/mol. The complex [AgS203]- is less stable: ?G0 = 486 kJ/mol. It should be noted that despite the high stability of gold complexes, the sodium thiosulfate may decompose to sulfite and elemental sulfur during the process, especially when heating. Gold is slightly soluble in the sodium sulfite solution, however it forms the strong complex [Au(SO3)2]3-. Depending on the concentration of free S2O32-ions, silver with sodium sulfite forms three complexes: [AgSO3]-, [Ag(SO3)2]3- and [Ag(SO3)3]5-. The dissolution speed of gold in sodium sulfite solution may be in the same range as it is during cyanidation. In this case, a practical application of sulfite process can be also used, especially for the products containing free elemental sulfur. In conclusion, sulfite-thiosulfate gold lixiviants can be used for concentrates after pressure oxidation of the cakes.

Sep 13, 2010