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By Q Johnston

Since its inception in 1990, improved metallurgical processing technologies, coupled with mine planning enhancements and improved geological knowledge, have sequentially enabled better efficiencies and economies of scale at the Macraes Gold Project. Over a period of 11 years, processing enhancements have been achieved by: +        increasing mill throughput, from one million tonnes per year, to current throughput of 3.9 million tonnes per year; +        improving recovery rates, from 70 % to approx 84 %; and +        performance enhancement through innovation, eg the use of kerosene to combat ClL pregrobbing. Future processing improvements have been identified in optimising the ore feed and processing flowsheet. The introduction of the autoclave has transformed the process flow form a traditional 'mill headgrade and tonnes milled' operation, to a 'sulphur/gold ratio and sulphur tonnes oxidised' operation.

Jan 1, 2001

THE filter-press, which has done so much for the successful treatment of the sulpho-telluride ores of Kalgoorlie, has a serious rival in the vacuum process, and this paper is written with a view to arousing more interest in the cheaper working of the press, it being doubtful whether its efficiency in extraction can be improved upon.Before proceeding with the actual working of the press, it may be as well to make brief mention of the character of the ore treated at the Associated Northern Blocks, where these notes were compiled.A sample from several weeks' run was taken of the raw ore, with the following analysis...

Jan 1, 1910

Whilst much has been written in past years by geologists, scientists, mining engineers, etc., regarding the well·known and justly notorious anticlinal, or, as they are more commonly known, " saddle" reefs of Bendigo, comparatively little noticehas been given to the synclinal or "inverted saddle "reefs and their relationship with each other. In taking up the question of the synclinal folds, I recognise that it is a large undertaking to confine within the limits of a short paper, and at the same time convey a comprehensive idea of their characteristics, and the importance of their relationship with the anticlinal folds, in the general question of practical mining. However, from a practical point of view I consider the question of great importance, and if an interest in it can be awakened, more particularly among practical men, the object of this paper will be achieved.Before entering into the subject I must briefly state some facts, and perhaps some theories, in respect to the deposition of the Lower Silurian rocks, and their subsequent buckling up, as now seen on the Bendigo gold-field. At the same time, I do not intend to go very closely into the geological aspect of the question, as I wish the paper to be considered as a practical one.

Jan 1, 1902

All development proposals have to run the gauntlet of the approvals process. Major resource projects are generally subject to particularly intense scrutiny. The key element in the approvals process is that it is about making decisions that take into account the benefits or otherwise to society as a whole - the interests of any one group do not take precedence. Most groups tend to see their relatively narrow interests as representing those of the broader society. Each group develops their arguments for or against a project in isolation, and then presents these to an arbiter in an adversarial situation. From this mire of argument and counter-argument it is often difficult to discern just what the real benefits of a project are, and opportunities for agreement and constructive modification of proposals to meet real concerns are often missed. The contention made in this paper is that the inevitable differences between these various viewpoints should be harnessed to help the proponent to come up with a proposal that is clearly of overall benefit to society and which gains approval. It is better to accept that no one group has a monopoly on wisdom in this area and to engender an environment of creative tension in which the pros and cons can be broadly considered and good planning and design used to produce a proposal that has a high chance of success. There are a variety of ways in which this approach can be implemented. Some of these options will be discussed in terms of their likely applicability to energy projects and their potential for success.

Jan 1, 1992

By S Hanrahan, S McLaughlin

A case study is presented that details the safety journey at a North American project involving two major contracts: a 1000 m shaft recovery and rehabilitation, and the development of a drainage gallery in a large open pit operation. In the early stages of the contracts, there were a number of incidents that created tension between the owner and contractor, which resulted in the contractor being placed on a final warning with almost imminent potential termination. As a result of this, it was agreed to initiate a focused safety recovery plan as a ‘last chance’.Over a period of two years, the engagement and consequent performance of the contractor was turned around, steadily working to set it up for success such that in one of the contract work areas, a record of ‘one year LTI (lost time injury) free’ was achieved. The journey involved the owner and the contractor teams working cohesively to educate all parties in the safety requirements and, most importantly, providing the context and understanding for certain requirements being put in place. Early on in the process, it was recognised that the owner team unknowingly was an impediment in that they did not fully understand the safety requirements and so was not able to lead the way for the contractor effectively. The journey to rectify the situation was supported and followed up by focused engagement with the project team, which generated a progressive improvement in a very challenging environment.In particular, the contractor turnaround was significant and of enough value for the contractor to ultimately export some of the safety systems from this site to other contract sites. This demonstrated the ultimate benefit of the contractor understanding and buying into a safety culture and system.CITATION:Hanrahan, S and McLaughlin, S, 2016. Winning the safety battle, in Proceedings International Mine Management Conference, pp 181-186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By J A. Rowland

When executing a ventilation change the mine ventilation circuit is in a state of flux throughout the entire change period with discrete mine areas both under ventilated and/or over ventilated during the change process. Whilst routine risk reduction strategies such as removing electrical power and people from the mine are commonly deployed it is wise to complete the change in the shortest practical time frame. This not only minimises the chance of unacceptable concentrations of contaminants accumulating around the mine but reduces the impedance on production activities which are routinely suspended during these change periods. This paper firstly highlights the importance of the maintenance of an accurate ventilation model and discusses issues which should be considered to assist to maintain in it a suitable state of health. Further it provides some tips on how to monitor that your model is in an acceptable state of tune so that it can be confidently deployed in the change process. Finally, it details the sequential process how a finely tuned and accurate ventilation model can be utilised to carry out major ventilation changes according to appliance pressure adjustments only and without the need to constantly measure and check resultant branch flows throughout the whole change process. Also discussed are some simple practical tips which will help ensure that the ventilation change process will go according to the devised plan on the day and in the most appropriate order including checking the efficiency and accuracy of the change, after it is completed.

Oct 12, 2022

By J M. Marwan, B Tang

Strain-type rockbursts, or strainbursts, are characterised by a localised violent failure. Their cause is attributed primarily to the sudden release of strain energy, which accumulates in a volume of highly stressed rock as a result of mining activities. Examples of such phenomena are crown/sill pillar bursts created in the mining process, pillar crush in room-and-pillar mining, face ejection in drift development headings at depth, and floor bursts associated with deep shaft sinking. The paper describes a simple method for the assessment of crown pillar bursts in steeply dipping ore deposits which are extracted by the overhand cut-and-fill method. The method is based on a theory previously established by the author to help assess the need for a remedial solution such as pillar destress blasting. Basically, the mining-induced energy storage rate (ESR) in the pillar is compared with the critical strain energy to come up with the so-called burst potential index (BPI).

Jan 1, 2001

By J D. St George

Flyrock is the unexpected and undesirable projection of rock fragments during detonation of a blast and managing this risk is becoming an increasing challenge as urban development encroach toward mineral extraction sites. The basic factors associated with flyrock are discussed in relation to geology, blast design and management. Published data of historical flyrock events are investigated and compared with local information on incidents. Good agreement was found between the data sets. A computer program of flyrock was developed using projectile motion based on launch velocity and angle, rock size, shape and density. This deterministic model was coupled with a probability model to simulate blast events. The impulse time ?t of the explosive pressure was taken as the stochastic variable to replace launch velocity. The variables were calibrated to replicate field data. A simulation was executed to demonstrate the capability of the approach to defining flyrock danger zones. For a simplistic situation it was identified that an appropriate distance to be cordoned off for the blast danger zone is a radius of 120 m in front of the blast and 65 m behind.

Jan 1, 2001

Study on Mineral Processing for a Cassiterite Ore in Southwest China

Sep 13, 2010

By R Shaw, M Hidding

The design of primary sample cutters for high-capacity conveyors is critical to achieving a correct sample, both in collecting the sample and ensuring smooth sample discharge flow. Modelling usually occurs at the design stage and requires extensive experience to achieve the correct result. However, it is difficult to confirm the effectiveness of the cutter design until after installation. Even with high-speed video, confirmation of complete sample capture is difficult, especially if the material characteristics change over time. Recent investigation using discrete element method (DEM) simulation to model the flow of the ore into the cutter and observe how it interacts with the cutter has revealed some interesting design requirements not observed in the past. By including DEM modelling, the correct design and optimisation of the cutter can be more accurately determined prior to commissioning.CITATION:Hidding, M and Shaw, R, 2017. Modelling ore flow in the design of high-capacity sample cutters, in Proceedings Eighth World Conference on Sampling and Blending , pp 145–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Chelopech Mining EAD and Best Available Techniques for Management of Waste Rock in Mining Activities

Sep 13, 2010

The Takasima Coal Mines comprise four islands near the entrance to Nagasaki Harbour, and are owned and worked by the Mitsu Bishi Company.There are several unusual features in the occurrence and working of these coal seams, the steep angle of "dip," the numerous seams of good coal separated by hundreds of feet of sedimentary rocks, the extensive faulting of the strata, and the way in which the coal is won, when so little surface is available for works, and where there is the ever present danger of subsidence of the roof and consequent flooding of the workings by the ocean. The author trusts that short notes on these few points will be of interest to members.The Islands are named respectively Hasima (Extreme Island), Nakanosima (Middle Island), Takasima (High Island), and Yokosima, and are situated about one mile from the main land.

Jan 1, 1901

Pilot-Scale Study of Deep Cone Thickener for Phosphatic Clay Dewatering

Sep 13, 2010

Hydrogen and carbon monoxide reduction data were obtained on pelletized materials of the type currently being prepared commercially in Australia.Pellets, approximately 1 cm diameter, made from Deepdale, Iron Prince, and Mt. Newman iron ore were reduced by hydrogen over the temperature range 500°-900°C and the reduced pellets were examined by thermogravimetric, microscopic, electron probe, and x-ray techniques. After an initial time delay it was found that up to 95 per cent reduction the data could be described by a porous model where gaseous diffusion through the solid is rate controlling. Independent measurements of effective diffusivity supported the values obtained from the reduction data. Above 95 per cent reduction the rate decreased markedly due to the formation of retained wustite or fayalite.Comparison with reduction by carbon monoxide over the temperature range 750°-900°C showed that the rate of reduction was approximately five times slower than for reduction by hydrogen.The rate of reduction was found to be a function of the initial properties of the pellets which may account for the widely conflicting results that have been obtained with previous investigations on porous pellets.

Jan 1, 1971

The Fraser Range is composed dominantly of basic pyroxene granulites derived from basalts, many of which appear to have been vesicular and pillowed. Acidic and basic garnet-bearing granulites are important in the west, and acidic granulites and narrow anorthosite layers are dominant in some regions east of the Fraser Range. An extensive flat-lying olivine gabbro sheet cuts the granulites, and in places has been converted to spineI-bearingmeta-gabbros and pyroxene granulites. The granulites of the Fraser Range (Proterozoic) are separated from the gneisses and schists of the goldfields regions (Archaean) by the Fraser Fault, over which there is a large gravity anomaly (gradient 20 milligals per mile). Some of the problems associated with the concentration of Cu, and Ni liberated from mineral lattices during metamorphism, and other principles of metal concentration in granulite terranes, are discussed. The recognition of vesicular and pillowed zones, even though highly metamorphosed, is of fundamental importance.

Jan 1, 1969

By J Holdsworth, L Sutton, A Lavrinec, D Ilic

Air quality is a big topic of discussion in regional mining communities as well as urban environments situated close to port terminals handling bulk solids. Community perception of poor air quality can significantly affect the reputation of the mining operation and handling facilities. Dust monitoring for regulatory compliance relies on using a handful of accurate but very expensive sensors, usually situated at the boundary, relatively far from the activities that generate the airborne dust. These reference monitors measure dust leaving the site but dust mitigation and management on-site largely relies on operator judgement. At a fraction of the cost, small wireless solar powered units can be used to supplement reference monitors in real-time. Due to their compact nature, portability and low price, these units can be implemented on a mass scale to increase spatial resolution of dust measurements and, more importantly, in much closer proximity to both the dust generating activity and the sources of dust. This can provide valuable insights into the origins and timing of dust generation thus producing datadriven decision-making while minimising subjectivity. Similarly, light detection and ranging (LiDAR) is another supplemental technology that can be used to increase the spatial resolution of dust measurements in near real-time, however, the cost of commercial systems even exceeds that of regulatory monitors. LiDAR also presents difficulties in quantifying dust plume concentrations. This study presents learnings of implementing both technologies for dust emissions management. Several low-cost sensor units and a fast-scanning custom-built 3D LiDAR system operating at a range of 1.5 km with a resolution of 1.5 m were deployed on a surface mine to monitor dust emissions from different activities. The project explores the use of real-time sensor data to quantify LiDAR measurements in parallel with integration into mine planning. The approach can assist in prioritising dust mitigation activities thereby reducing instances of emissions exceedance and minimising water use through databased and targeted application. Demonstrated is an opportunity for a step-change in industry best practice as well as commercialisation and operationalisation of the method across different industries, including future mineral extraction.

Sep 18, 2023

Study on Mineral Processing of Refractory Copper-Nickel Ore

Sep 13, 2010

The areas of concern lay in the processing of, and the subsequent hearing into, Waihi Gold's resource consent applications to extend Martha Mine. The proposed amendments to the Resource Management Act 1991 might see the introduction of contestability in the processing of applications - which would have assisted Waihi Gold; and the use of commissioners to hear the applications, with a right of appeal to the Environment Court on points of law only. It is also proposed to have major applications heard directly by the Environment Court. If Waihi Gold's applications had been heard at first instance by the Court, the delays in time and associated costs would have been reduced. However a hearing by commissioners only would not have been satisfactory, there being no right of appeal against the conditions of consent, which if implemented as granted by the Councils would have had a significant impact on the costs associated with the extended project.

Jan 1, 1998

By P Audet, D Doley

The mining industry often embraces mine closure criteria that require the reinstatement of predisturbance or even presettlement (ie historic) ecosystems. However, the extent and severity of disturbance associated with most mining activities mean that critical physical and biological characteristics are irreversibly altered. Consequently, it is rare that a reconstructed landscape can support ecosystems even close to the historic condition, and this rarity is reflected in the small number of mine leases that have been extinguished by attainment of such completion criteria. Novel ecosystems are defined as those in which some or all physical and biotic components are irreversibly different from the historic condition. Recognition of the concept of novel ecosystems allows mine closure criteria to be set according to attainable physical and biological conditions that provide safe, stable and manageable environments with acceptable ecological functions. We propose that a landscape that first maximises physical stability and economy yet will provide a range of environments for vegetation communities and fauna habitats that may be very different from those existing prior to a disturbance should be considered suitable alternatives to, eg targeting idealised historic environments. As a result, mine closure criteria should be established by detailed description of the best attainable physical conditions, with negotiated identification and testing of the most appropriate biological systems for the various parts of the reconstructed landscape. As a general practice, revegetation would use native, but not necessarily local species if the new physical environment is not conducive to the survival and growth of local species. These new ecosystems would need to be managed in perpetuity, although the intensity of management might be low if landscape design and engineering are combined with appropriate species introductions. Here, we suggest an abbreviated procedure that may be adapted in light of local conditions and circumstances for guiding decisions influencing the physical and biological properties of reconstructed landscapes that will enable novel ecosystems to meet realistic closure criteria.CITATION:Doley, D and Audet, P, 2014. Changing restoration priorities in the 21st century – opportunities for novel ecosystem design in mine closure, in Proceedings Life-of-Mine 2014 , pp 649–662 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Tumbling mills and some theoretical and practical aspects of milling are discussed. Attention is directed towards the difficulty of relating the dynamical analyses of the motions of particles within mills to the existing treatments of breakage processes. This synthesis may be advanced by a study of milling that utilizes the matrix analysis of breakage processes. Application of the matrix analysis to results obtained on (i) grinding in open-circuit a zinc ore in a conical pebble mill and in a modified conical mill, (ii) "grinding of cement clinker in a compound mill, and (iii) to some drop-weight grindability tests is discussed. It is shown that the 'IT-breakage model adequately describes the breakage processes of each of the tests. (The proportion broken in each breakage cycle is given by 'IT and is independent of particle size.)The size distributions of the products are accurately predicted in the cases considered. Matrix analyses of the breakage of coals, various ores and a cement clinker have been made. Appendices give an elementary account of the matrix methods and give the equations fully describing reverse order closed circuit operations. The matrix analyses of breakage processes and the survey are used to examine briefly closed circuit grinding.INTRODUCTIONTumbling mills are slow-speed crushing and grinding machines which have been developed from some fairly simple types into many widely differing forms. Many of these versatile mills have proved extremely useful in ore dressing and mineral beneficiation, whereas others have been used in the cement industry and less extensively in the coal industry.The performance of even the simplest tumbling mill is very imperfectly understood, whilst the more difficult problems associated with the balancing of complex milling circuits and with the establishment of the optimum operating conditions for the whole of a complex circuit are even less well apprehended.Our knowledge of the performance of tumbling mills is rather sharply divided into two categories: the first consists...

Jan 1, 1957