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By Balks AI

Systematic roof bolting in Australian coal mines began at Elrington Colliery in 19)49. Since that time the proportion of the roof supported by roof bolts has increased until, in 1970, 1.5 million were installed in Australian coal mines. This rapid growth of roof bolting has meant that the range and variety of roof bolting machines has altered also. The-number of machines now available both to bore holes and place roof bolts has increased. to the point where both rotary and per- cussive machines are used extensively. Generally, until the last four years, roof bolting machinery in Australia followed the practices in vogue in the United States. However, in -recent time the particular problems of Australian coal mining have necessitated the development of equipment primarily suitable to Australian conditions.

Jan 1, 1971

By Krokhmai VS, Sayko OP

The paper summarises the theoretical and experimental studies which led to the development of new industrial equipment designed to recover liberated gold from placer gravity concentrates. The new technology is based on environmentally clean magnetic methods, which avoids use of mercury in the production process and obtains higher gold recoveries compared to the amalgamation technique, and which can reach 98.6 - 99.5 per cent. The complex of equipment thus developed is now commercially used at nine Russian gold mining operations. Six more such complexes are due to come on stream in 1993, some of them outside the CIS. The new technology appears to hold much promise for the recovery of precious stones (diamonds, rubies etc) semi-precious stones (pyropes, chrysolites etc) and also artificial diamonds, for which case there are encouraging laboratory results.

Jan 1, 1993

By Moon N. T, Torrance A. C

This study has considered the effect of mechanical shock on the resilience of the glass microspheres commonly used to sensitize an explosive emulsion. The damage to the glass microspheres caused by detonating cord, emulsion manufacture and the manufacture of the glass microspheres were considered along with the effect of sensitizer concentration on explosive performance. Reductions of up to 50% in the glass microsphere concentration of an emulsion explosive can result from poor initiation practice, such as the use of high strength detonating cord as downlines during initiation. Laboratory results suggest that detonating cords of strength greater than 3.5 g/metre should not be used as this can seriously affect explosive performance, particularly in small diameter charges. This reduced performance results from damage to the sensitizer elements and recrystallization of part of the emulsion phase.

Jan 1, 1990

As Project Managers for the Blair Athol Coal Mine Project, CMPS selected a number of computer systems to assist in project control. The areas where computers were used were: 1) Planning & Scheduling 2) Procurement Reporting 3) Document Control 4) Accounting 5) Cost Control 6) Control of project management and engineering manhours The computer packages selected were generally effective in their own areas. During 1982, CMPS acquired an in-house project control package called GC/Cue. Project control systems for the project are progressively being set up on this system. The advantages of this type of system are: 1) Improved accessibility of information, due to on-line operation and the use of VDU's. 2) Improved turn around time for computer runs and production of reports. 3) Improved presentation and format of reports. 4) Lower costs.

Jan 1, 1983

By Elpatyevskaya VP, Arzhanova VS

Main geochemical problems concerning the environment and mining industry interrelation are connected with the transformation of natural water chemistry by mining wastes. The investigation of many mines in Primorye, the southern part of the Russian Far East, showed that their mining waters have high concentrations of heavy metals and aluminium. Water acidity is primarily connected with the amount of acid-forming sulphide minerals in ores and also depends on the neutralising capacity of rocks. Considerable quantity of metals occur in the waters in dissolved form. Metal concentrations in mining waters exceeds the natural levels by 2-5 orders of magnitude and can't be reduced to the background levels even after multiple dilution. It is necessary to develop and put into practice new technologies so that to reduce the geochemical impact upon the environment.

Jan 1, 1995

This paper provides an overview of the future for underground thick seam coal mining in Australia. It reviews the available and anticipated mining systems and technologies which may be adopted to mine coal seams of greater than 4.5 m thickness, together with an assessment of the likely technological and operational risks and challenges involved. This overview of mining systems is presented in the context of both current and recently completed research projects funded through the Australian Coal Association Research Program (ACARP). The projects have been joint investigations between The University of New South Wales Mining Research Centre (UMRC) and the Centre for Mining Technology and Equipment (CMTE). Outcomes from the projects have included an appraisal and classification of underground thick seam reserves in Australia and their suitability for each mining method.

Jan 1, 2000

Asarco's newest concentrator near Troy, Montana, began operation in October 1981, and is presently milling ore at its design capacity of 7,710 metric tonnes per day. The underground room-and-pillar mine produces a readily floatable copper sulfide- native silver ore in a quartzite gangue. Major sulfide minerals are bornite and chalcocite with minor chalcopyrite; fine grained native silver occurs with the copper sulfides. There are also minor amounts of native copper and copper oxides in the ore. A rougher copper-silver concentrate is floated, reground and cleaned twice. Cleaner tail is scavenged, and the scavenger concen- trate is combined with rougher concentrate for regrinding. Rougher flotation tailing and scavenger tailing make up final mill tailing which is disposed of by spigotting into a tailing dam located 10.5 km from the mill site.

Jan 1, 1978

The aspect ratio (mill diameter/mill length) of autogenous and semi autogenous mills varies widely and can be as high as three or as low as 0.5. The literature on the subject of what effect aspect ratio has on grinding mill performance or energy efficiency is almost non-existent. However, at the design stage of many grinding circuits the subject is often vigorously debated amongst metallurgists. In this paper the performance characteristics of mills with different aspect ratios are examined to determine whether process performance characteristics are a function of aspect ratio and whether high aspect ratio mills are any more or less energy efficient than low aspect ratio units. Data from both pilot and full-scale mills are used for this purpose in open and closed circuit configurations.

Jan 1, 2007

The prospect of utilization of phosphate ores which contain high P205 values associated with Al and Fe has produced a great deal of interest over many years. Processing options have generally been based on the utilization of by-products which were required to offset the processing costs.This paper presents a range of processing options which have been investigated at laboratory or technical scale on phosphate ores which predominantly consist of crandallite, CaA13(PO4)2(OH)5.3H20 and millisite, Ca(NaK)Al6(PO4)4(OH)9.3H20. Christmas Island (Indian Ocean) and Mt. Weld (Western Australia) phosphate ores are good examples of such feedstocks. It is expected that these processes may also be applicable to such phosphate ores from other locations.

Jan 1, 1990

By Mills JC, Belcher CB

X-ray fluorescence spectrometry is used videly for routine quality control of the mining, )lending and agglomeration of iron ores. Most )f the procedures used, cannot tolerate significant changes in matrix composition or be Lpplied to a wide range of elements. Accord- ngly, a graphite briquette technique which is Lpplicable to some fifty elements in widely Tarying iron ore matrices is described. The ignificant advantages are suitability of the ame preparation for both optical emission and -ray spectrometry, a complete elemental overage for the range 5bcg/g to 100%, and the recision and accuracy of the methods are om.parable with the standard chemical.methods hich have been superseded in the authors' boratories. The proposed methods become ore attractive and economical as more prehensive information is sought.

Jan 1, 1975

Gallery Stoping, an old but little used stoping method, has been reintroduced to workings at the Paringa South Shaft.Orebodies which are amenable to such a method are being mined in this manner with considerable advantages and savings.The advantages of gallery stoping as used at Paringa, compared with traditional mining methods are:1. constant cash flow2. low set up cost and initial stope development3. nearly 1005 recovery 4. no access problems 5. quicker tonnagesAs compared with highly mechanized mining methods, it has been found to be slower but requires less development, gives improved grade control, has less impact on the surrounding rock and fragmentation is much better, reducing secondary blasting costs.This paper examines the mining method and illustrates the advantages of gallery stoping at Paringa.

Jan 1, 1985

By H J. J Boshoff

Mine closure planning integrated into life-of-mine (LOM) planning during the operational phase consists of many subcategories. One of these subcategories that needs to be fully integrated into the LOM planning is that of water management planning. Issues arise when mine water management infrastructure, which is required post-mine closure, is only considered closer to the end of LOM. Once the mine is closed monitoring is focused on water quality as an indicator of closure performance, hence inadequate upfront post-mining water management planning or integration into operations will result in environmental harm. The lack of considering post-mining water management is not uncommon in LOM planning. Poor mine site water management and planning are a wide reaching problem for the mining industry. Numerous active mines have been issued with environmental notices and penalties for contaminated water discharge; including issues with abandoned mines now being cared for by governments all over the world.Mitigating sources of water contamination caused by existing and closed mine sites that are leaching pollutants might be impractical, due to inaccessibility to the contaminants or final landform topography. The opportunity to consider and introduce post-closure required mine water management infrastructure is lost once the waste facilities are constructed. Mitigating contamination is made more problematic with mines located in remote areas, serviced by dedicated roads, water supply, electrical supply, etc. It is expected that these services will be decommissioned or drastically reduced, once closure is reached making remedial work much harder. Inadequate planning, to ensure access and easily maintainable water management infrastructure, could lead to erosion and contamination going unnoticed. There are numerous examples of poor mine water management practices in Africa, Asia, Australia, South and North America. In the United States more than 23 000 km of streams are affected by pollution sourced from some 50 000 abandoned or mature mine sites (DeGraff, 2007).CITATION:Boshoff, H J J, ?2014. Inadequate water management planning resulting in long-term closure liabilities, in Proceedings Life-of-Mine 2014 , pp 233–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By J Nixon

I have to say that my story is not too much different to many others who grew up and worked in the great mining fields like Broken Hill, Mt Isa, Rosebery, Kalgoorlie or Kambalda and any one of them could have stood up here and spun you a good yarn.What does my paper offer you in this volume? By sharing my experiences I want to encourage you to consider your own experience with leadership, taking on change, learning from and contributing to the development of others.I have been very fortunate to be part of many new innovations into underground mining over the past 40 or so years; most of it with Conzinc Rio Tinto Australia (CRA)/Rio Tinto operations.•From hand-held drills and a homemade single boom Jumbo mounted on an old Airtrak, to the sophisticated twin boom jumbos with high speed drifters all controlled by an on-board computer;•from a Scraper winch and a Wagner 2D loader to fully automated electric LHDs that navigate to the tipple, empty the bucket and return to where they come from;•from hand-held cut-and-fill and timber stoping in Broken Hill to the bulk mining methods of a block cave where at Northparkes we mined more ore in a month than we mined in the total five years of operations at Currawang;•from hand-held scaling and bolting with no skin protection to installing ground support with Jumbos and sophisticated Cable Bolters and the introduction of in cycle shotcrete;•from hand-held ladder rising and shaft sinking to Box Hole rigs, Raise Bore Machines and Blind Hole shaft sinking; and•from Gelignite based AN60 stick explosives, ANFO, fuse firing and half second detonators to Powergel, Emulsions and electronic computer programmed detonators that can somehow be initiated by ‘Blast Ped’ travelling through the rock.

Mar 21, 2011

By X Li, W McKeague, M S. Powell

This paper explores the importance of operators in the overall efficiency of mineral processing plants. With the potential of future control configurations becoming more remote, it is time to review the implementation of control and utilisation of operators. This paper is based on a preliminary review of operators and control room operations and clearly shows that, in the minerals industry, operations are typically run in a reactive mode (with a focus on ensuring equipment operation), rather than in a proactive mode (with a focus on optimising the process performance). The primary reason for this misguided approach is the short sighted thinking applied to the challenges of designing technology and organisational tools capable of addressing the essential operational needs: an approach which inevitably results in a disconnect between people and technology. Contrary to the popular approach of replacing operators with expert systems, the thesis of this paper is that the shift to more complex circuits, with higher demands on processing capability and control, will require the actual upskilling of operators. Experience in mineral processing and other industries indicates that expert systems cope well with small changes but are typically unable to respond to major changes in feed material and this is where the expert operator becomes crucial. Providing operators with ongoing high level training in process understanding, and restructuring how they interact with the plant and interface with the control system is the approach being proposed here - an approach surprisingly underutilised and often absent in the minerals industry today.CITATION:Li, X, Powell, M S and McKeague, W, 2012. Unlocking processing potential by empowering our operators, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 333-340 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By S Brochot, M-V Durance

In many cases, current metallurgical accounting practice does not consider the errors associated with the measurements used in obtaining the metal balance. Considering all measurement errors, including errors associated at each step of the process - from sampling and analytical errors to measurement errors in circuit instrumentation, can improve the accuracy of the final metal balance - assisting in the improvement of process performance, optimisation and control.The consequences of the inclusion of measurement errors on metal balance for different circuit configurations and typical metallurgical accounting practice (two product and three product formulae) will be discussed in this paper.Examples of the tools, methodology of implementation, and periodical metal balance tasks are presented to illustrate the advantage of this approach in meeting the different requirements of each department.CITATION:Brochot, S and Durance, M-V, 2012. A new approach to metallurgical accounting, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 217-224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By W B. Edgar, S C. Dominy

High-nugget effect vein-gold systems are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of Ore Reserves at production start-up. However, despite the well-known risks, these deposits often have a grade upside that makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The use of the grade estimate supported by a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion based estimates through to data-based estimates and geostatistical conditional simulation. Whichever method used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties.CITATION:Dominy, S C and Edgar, W B, 2012. Approaches to reporting grade uncertainty in high-nugget gold vein projects, in Proceedings Project Evaluation 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By R N. Humphries

The aim of this paper is to question the need to develop bespoke monitoring and assessment methodologies and criteria, thereby ‘reinventing the wheel’, when designing and assessing the success of important natural habitat and ecosystem restoration schemes at mine sites in the UK and Australia. It draws attention to the existence and applicability of the Phase I Habitat, National Vegetation Classification (NVC) and Condition Monitoring methods in the UK and similar approaches used in Australia. These are long accepted established methodologies and have published accounts for describing, assessing and managing natural vegetation communities, habitats and ecosystems. They are often used at the environmental impact stage, but seemingly rarely, if at all, in restoration design and management at mine closure. Their application to mine restoration and closure is illustrated and discussed by reference to a surface coalmine in South Wales, UK.It is concluded that the application of a combination of the Phase I Habitat, NVC and Condition Monitoring methods is highly relevant to the expectations of the Convention on Biological Diversity (CBD) and its implementation in the UK, and probably in Australia too. The methodology and criteria described could be incorporated into the guidance and specified in the mining permits so that there is clarity as to the expectations and requirements for monitoring and assessment for bond release. Their use could be of wider application where there is a requirement to assess the success of restored CBD assets and ecosystems.CITATION:Humphries, R N, 2014. Why reinvent the wheel when there are established methodologies to aid the design and assessment of restored natural ecosystems on mined land?, in Proceedings Life-of-Mine 2014 , pp 675–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P B. Hills

Almost a quarter of a century since Bridges (1993) documented techniques for the assessment of ground conditions in a seminal paper in the Proceedings Second International Mining Geology Conference, the necessary role of the geologist in recording geotechnical data on exploration properties and in mines remains. Typically, the geologist is the first professional on the exploration property. Of course, most exploration properties don’t become mines. However, when a property does start to come together and form a coherent mineral deposit and professionals from across the minerals industry spectrum, including specialist geotechnical engineers, become increasingly involved, it remains the geologist who has the most intimate knowledge of the deposit. By association, that knowledge extends to the character of the rock mass.Throughout the various phases of prefeasibility, feasibility, construction and production, culminating in the mature mine, the knowledge of the rock mass held by the geologists continues to grow. In the current era of minimising cost and optimising profit, meeting the requirements and expectations of stakeholders ranging from fellow employees to investors, industry and financial regulators and the broader public, in a social environment where occupational health and safety concerns are of uppermost concern in every endeavour, the value of the geologists’ observations cannot be understated. Mines nowadays employ more geotechnical engineers than they did in the early 1990s when Bridges (1993) wrote his paper. More funds are available for specific geotechnical investigations of exploration properties and mines; none-the-less, those programs remain limited in their extent and there is a wealth of additional data available for collection with the appropriate training, at little additional effort. Fundamentally it is all about the numbers. Any hole not geotechnically logged is a hole that will need to be drilled again if the data is required. Any face, surface or underground, not geotechnically mapped is one that may need to be mapped a second time. That doesn’t mean every hole or every face. However, it is the proposition of this paper that the opportunity for additional geotechnical data to be gathered during traditional geological investigations is an opportunity that cannot be ignored. Occupational health and safety requirements demand that the geotechnical risks associated with mining are appropriately managed. Mining regulations in most Australian and overseas jurisdictions requires the consideration of geotechnical risk through formalised management plans. The Joint Ore Reserves Committee (JORC) Code requires the consideration of modifying factors more than ever before. The benefit to be realised through improved geotechnical understanding by geologists on the ground leads to improved occupational health and safety, optimised reporting compliance, and improved financial and social outcomes for the exploration property and ultimately for the mine that follows.CITATION:Hills, P B, 2017. The necessary role of the geologist in geotechnical data gathering, in Proceedings Tenth International Mining Geology Conference 2017, pp 347–354 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

The total cost of horizontal development can be minimised by optimising the cost of each of the component operations (eg drilling, blasting, etc). Component costs should not be minimised. To optimise blasting results (ie the mean advance per round, muckpile characteristics and overbreak), operators need to optimise the blast design and drilling and blasting procedures. The costs of pulling extremely long (say >6 m) rounds, producing unnecessarily fine fragmentation, and minimising overbreak are excessively high. Operators should continually consider how they can shorten the cycle period by saving time at the face. To enable it to be matched to the pertinent rock properties, the blast design needs to be based on as much relevant experience as possible. To develop the most valid correlation between blasting results and blast design, the latter must be implemented carefully and accurately, but without sacrificing speed excessively. The total cost can often be reduced by using: 1. computer-controlled jumbos (to reduce the period and cost of drilling and to increase drilling accuracy); 2. larger diameter (51 mm to 64 mm) and longer (4.5 m to 6 m) blastholes; 3. at least three large diameter ( ¦89 mm) relief holes that are 0.2 m to 0.3 m longer than the blastholes; 4. explosive products that are selected on the basis of proven reliability and overall cost efficiency rather than price; and5. stemming (to increase the amount of effective work done by each kilogram of explosive and, hence, to reduce the powder factor and possibly the number of blastholes and the costs of drilling and initiation). Non-perimeter blastholes should be charged with ANFO or a bulk emulsion of established performance. Upper perimeter blastholes should be charged with a bulk explosive with a much lower effective density. But where geology varies considerably, greatest control over overbreak could possibly be achieved with the versatile pre-assembled charge shown in Figure 1. This paper presents numerous potential ways in which the total cost of development can be minimised. It concentrates on recommending blast design features and the safe, rapid, cost-effective implementation of designs.

Jan 1, 1998

By M Darvall And R Fare, D Dormer

The Argo Archaean lode gold deposit is hosted within a structurally complex shear zone system, 70 km south of Kalgoorlie, and 3 km west of the crustal-scale Boulder û Lefroy Fault. Argo is an active underground mine currently producing at a rate of 120 koz pa with a Probable and Proven Reserve as at December 2005 of 2.19 Mt at 5.94 g/t Au (419 koz), a reduction on the December 2004 Probable and Proven Reserve of 4.58 Mt at 5.74 g/t Au (845 koz). This Reserve is hosted in six separate gold bearing lodes within the Argo shear system. Presently, a further six subeconomic shears are recognised. The 2005 Reserve figure represents a reduction of 426 koz compared to the 2004 Reserve as a result of a thorough review of the geological interpretation/resource model, and engineering factors applied to the Resource/Reserve, and depletion due to mining. Year on year Resource/Reserve figures at Argo had gradually increased as additional information on the system became available and mining methods were increasingly resolved with early production. The portal for Argo underground mine was cut in June 2002 within the highly profitable Argo open pit. The proposed æAvocaÆ bottom-up mining method required extensive lead time between development and the commencement of stoping in April 2004. During development considerable additional complexity in the Resource was encountered. Additional structures were identified, and complex splay interactions affecting the geology impacted on development. Intensive concurrent exploration in the footwall to the main lode during this period was the main cause of the increase in the Resource/Reserve figures during early development. As development progressed, lower grade continuity was observed than was previously interpreted. At the same time, drilling of deeper portions of the deposit and subsequent reinterpretation of the geological model significantly reduced strike lengths of economic mineralisation. Radical changes to the mining methods were required to improve productivities and to satisfy geotechnical considerations. The changes altered the engineering factors applied, which resulted in a reduction in the Reserve figures.

Jan 1, 2006