Search Documents

By Moxon N. T, Berndt J. R

BHP-Utah Coal Limited's Peak Downs Mine is located in Cen- tral Queensland, approximately 200 km south west of Mackay. The annual raw coal production of the mine is over 8 million tpa, requiring the removal of about 40 million cubic metres of prime overburden. This is achieved through the use of five large draglines. The large depths of overburden (up to 55 metres) encountered over half the strike length of the mine enables cast blasting to be carried out in conjunction with draglines employ- ing the chopping method of digging. The objective of cast blast- ing is to use explosive energy to move as much material directly into spoil as possible. The additional costs of drilling and blast- ing are offset by reducing dragline rehandle. Two factors which are of primary importance to the design of cast blasts are initiation control and material velocity. High speed motion picture photography is a powerful diagnostic tool to quantify these aspects of blasting (Winzer, Montenyohl and Ritter, 1979; Chiappetta et al., 1983; Anon., 1983). The objec- tives of such analysis are to: 1. Determine the burden velocity, 2. Determine the time to initial movement (that is, the inter- val between a face hole firing and the initial movement of the burden), 3. Check the accuracy of the initiation sequence. BHP Central Research Laboratories (CRL) and Peak Downs Mine monitored a cast blast in the mine's Winchester Pit on 18 August, 1988. The objectives of this exercise were to: 1. Quantify current cast blast performance, providing a base case for comparison with modified blast design. 2. Compare two orientations of angled holes within the blast. 3. Assess the effectiveness of cast blasting utilising an air-deck. 4. Check blast timing with respect to burden movement times.

Jan 1, 1989

In the introduction to a recent paper dealing with, the relationships of magnetite and hematite in the banded iron formations or "jasper bars" of the Western Australian pre-Cambrian(17)t the author made a brief mention of these interesting rocks, of the principal series in which they occur and of a few of the rock and mineral types to be found within them.He drew attention to the essential shnilarity of these Western Australian banded iron formations to those of the pre-Cambrian of such other countries as the United States Lake Superior region, Sweden, South Russia, India, South Africa and Brazil, and gave a brief summary of his views as to the origin of the formations in Western Australia. Furthermore he stated that the banded iron formations have proved of considerable direct economic importance in the goldfields and other' regions of Western Australia, and he referred to the assistance they have provided the field geologist in geological mapping and the determination of geological structures.It is in elaboration of this last statement that the present paper has been written. In the following pages will be found some examples of the use to which the jasper bars have been put in the determination of the geological structure of critical areas in the goldfields of the State.Firstly, however, it may be as well to recapitulate the features of interest in these rocks. The true jasper bars or banded iron formations including the types jaspilite, banded hematite quartzite and banded magnetite quartzite or chert, together with their higher grade metamorphic derivatives such as banded magnetite-gruneri~ quartzites, magnetitegrunerite schists, fayalite ,and hedenbergite bearing handed magnetitegrunerite quartz rocks and' to 'a lesser extent magnetite-hypersthene grunerite quartz rocks, are abundant in the older series of the Western Australian pre-Cambrian. They are best developed in the older Greenstone or Kalgoorlie series of the goldfields districts, interbedded with metamorphosed basic lavas, tuffs and sediments. The mineralogy andpetrology of these rocks, the history of their metamorphism and their origin have been discusseq elsewhere in some detail by the author(19), (20). In one of the papers(20) it was clearly demonstrated that in the light of the true facts the old silicified shear zone theory of the origin of the jasper bars is quite untenable and that the formations undoubtedly represent sedimentary horizons as was recently pointed out by McKinstry(14).It has also been shown that banded ferruginous cherts, quartzites and cherty carbonate rocks of much lower metamorphic grade are well developed...

Jan 1, 1943

By P B. Card

"The website www.economicevaluation.com.au, which had its origins at the Project Evaluation Conference 2009, provides a free way for industry professionals to teach themselves economic evaluation. At its core is a set of fast-moving modules and three worked examples.The website recognises that economic evaluation is a discipline with a hierarchy of three levels:decision-makingevaluating the project/businesshands-on modelling.There are a set of modules for each level that describe the concepts and activities in detail. These emphasise that the most important and rewarding work is the evaluation of Level 2. The economic model created in Level 3 is merely a working tool and should not become a sophisticated ‘trophy’ in Excel that only one or two people can comfortably use.Hands-on modelling contains three sets of practices designed to make any model rigorous and intuitive so that it can be easily understood and used by others in the project team. Even if the model develops into a long, detailed and complex workbook, it should remain easy to follow and be intuitive. The website advocates freedom to devise any architecture that best suits the project under study, but promotes rigour through the following practices:four cash streams and graphsthree architectures – concept, prefeasibility and feasibilitysix principles.The modules in the Level 2 evaluation use conversational language to describe in detail the broad range of activities needed to properly understand and characterise a project/business. It stresses that net present value is nothing more than the mathematical treatment of a whole set of opinions, is not an absolute truth and is only a fraction of the evaluation process. The modules describe in detail the range of economic metrics that should be computed and the full spectrum of equally important characterisations required to make the decision in Level 3.CITATION:Card, P B, 2016. Teach yourself economic evaluation, in Proceedings Project Evaluation 2016, pp 160–171 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

Development of the Davcra flotation cell has continued over the past seven years. Preliminary testwork on single cells has now been extended to a com- plete Davcra flotation circuit, to cells ranging from 5 to 400 tons per hour capacity and to cells operating on a variety of materials. Operation of both test and production units has shown the Davcra cell to be competitive with conventional flotation machines. It offers a lower capital cost installation than conventional cells and in addition has a number of. operating advantages, particularly in its adaptability to automatic control.'

Jan 1, 1971

The role of the mine geologist in a business perspective is self-evident to some, but to others it may be a new concept. All mine geologists need to know exactly how they add value to the business if they are to be successful. Alternatively, if they do not add value, then they will become redundant. This paper seeks to understand some of the contributing problems that hinder the mine geologist from operating in a business perspective. In doing so, a new context (for some) is proposed to aid the mine geologist and the operation gain greater value from geology. The proposal suggests how to ensure that the activities of our geologists are intrinsically linked to the business process that we are involved in. The mine geologist can and must play a pivotal role in the success of an operation. To do this, they must understand some principles of business such as:process, customer/supplier relationships, and organisational structure. Our geologists must know the business objectives, understand the product that the customer needs and use their geological skills to deliver the product safely, on time and to specification. As geologists, we can be instrumental in ensuring that the operational environment is structured in such a way that maximum value is realised, not only from the mine geologists but the entire site team. In doing so, mine geologists will realise their full potential in delivering the outcomes the business demand, and therefore be recognised as strong contributors to business success.

Jan 1, 2000

By J Zhang, B Wei, T Zhao, K Wang

Understanding mining-induced surface movement and fissures is critical for environmental protection and geological prevention. In this study, image recognition algorithms, satellite remote sensing and unmanned aerial vehicle photogrammetry (UAVP) were combined to identify surface movement and fissures caused by mining, and a case study was conducted in a coalmine in western China, and the following conclusions were obtained.

Sep 1, 2024

The word governing derives from gubernare meaningto pilot a ship. Being inclined to metaphors, one could be forgiven to think that politicians act this verb and captain the Nation's ship into some definite course. In the case of at least the mineral resources industry, it seems that there are not many James Cook followers in our parliaments: Australia's approach to mineral and energy policy is often chaotic - witness the 1935 to 1961 ban on iron ore export-ing which prevented the development of a significant steel industry at time when the World was hungry for this metal, just to mention one amongst many other examples.The follies of Australia's mineral policies are well il-lustrated in the case of uranium mining. Although Australia had the Western World's largest economic reserves of uranium, it is onlythefifth producing nation and its uranium potential is largely unrealised. At the root of this situation are the interventionist attitudes and policies of successive Federal Governments which for more than four decades distorted the Investment decision and, in more recent times. discouraaed investment.

Jan 1, 1990

In the hard rocks of the Nordic countries of Norway, Sweden and Finland underground works have a long tradition. Today the subsurface has been taken into use for a wide variety of purposes. In this paper only the more uncon- ventional examples are described such as caverns for drinking water, sand bunkers, molasses silos, wine and liquor stores, cold stores, heat storage, waste disposal and state archives. The particular use of unlined high pressure tunnels and socalled air-cushions for hydropower schemes is discussed. The dual use of subsurface air-raid shelters for sports activities seems to be a special Nordic tradition. Some cost figures are given and the advantages of using the underground is Discussed.

Jan 1, 1987

By Yamamoto Y, Ohyama H

In case of NATM, mechanical cutting is desirable in view of the original purpose of not spoiling natural ground. As typical tunnelling machines, there are two (2) kinds available: one is "Full Face Excavator" known as TBM (tunnel boring machine), and the other is "Roadheader" known as Part Face Excavator. By the use of the former, accurate profile cut is made possible, but there is a limit in the shape of a cutting section. By the use of the latter, cutting of various sections is made possible, but in order to cut a section economically and accurately, operators are required to have a high level of skill. In this text, we introduce Automatic Controlled Profile Cutting System (hereafter "ACPC" System) developed as a roadheader.

Jan 1, 1987

This paper describes a case history of using an integrated geochemical and hydrogeological approach to predicting solute transport from gold mine tailings in highly fractured volcanic terrain. Two modes of transport are identified, namely discrete fissure flow and diffuse seepage through the intervening weathered rock. A simple mass balance approach is used to predict concentrations at points of emergence because most of the seepage migration will be by way of the discrete fissures where advective transport will predominate. The mass balance method has been modified to allow for natural degradation of weak acid dissociable cyanide. The long term effects of diffuse seepage are also examined.

Jan 1, 1988

By Minchinton A

CPeX is a non-ideal explosive performance prediction model. The model takes into account the rate of energy release, the extent of chemical reac- tion and the effect of confinement on energy release. The model resolves the explosive energy into `shock' and `heave' com- ponents as a function of explosive type, hole diameter and rock type. The predictions of the model are compared for a bulk emulsion, and a prill-doped bulk emulsion in soft rock. The predictions, based on calibra- tion of the model with simple unconfined detonation velocity measure- ments, show the significant effect of non-ideality on explosive Performance.

Jan 1, 1988

By Johns D. R

The producers of mineral sands on the East Coast of Australia might be regarded as having a simple task of selling Rutile and Zircon. Such is not the case. Differing quality and grain size requirements plus the dramatic increase in the percentage of mineral sold in a processed form have meant a large increase in the number of different end products handled. The resulting sales control problems are compounded by the need to be able to deliver against a large number of separate contracts which may relate to spot or long term sales in small quantities or in bulk shipments. Methods of helping management control this situation have been devised and incorporated into a suite of computer programs. Experience with the approach has been very satisfactory. The effect of changes to shipping schedules, commitment to new or changed orders, or proposed changes to production can be evaluated as and when necessary with little bother. Confidence in decisions taken is high since the process of data collection has been designed to involve

Jan 1, 1977

By Butler RD

The Singhbhum Copper Belt is an arcuate zone of verthrusting which extends over a strike length of about 180 kilometres, located in Eastern India, 150-300 kilometres west of Calcutta. The Belt is noted for its mineralisation, and both copper and uranium are currently being mined within it.

Jan 1, 1990

By Ostrea AM

Aqueous oxidation in an autoclave at ele- vated temperatures and oxygen partial pres- sures is applied to Philippine gold-bearing sulfide ores and concentrates which respond poorly to conventional cyanidation. The gold concentrates are recovered from ores and tail- ings material using the patented OMLI Process (the OMLI Process is able to upgrade tailings material analyzing 0.50 g/t Au to a concen- trate with a grade of 5 g/t Au or better). The results show that with aqueous pre- oxidation of the concentrates ahead of cyani- dation a four-fold increase in gold recovery is obtained compared with straight cyanida- tion. The observed differences in response to the pre-treatment step between various mate- rials are correlated with their mineralogical composition. The chemistry of aqueous oxida- tion is also presented.

Jan 1, 1986

By Badal R

Rock Discontinuities ("joints") affect blasting results. An investigation was carried out to understand if blast parameter such as spacing needs to be altered with the change in joint direction. Small scale laboratory studies in jointed limestone blocks have been carried out. It is shown that optimum spacing is variable with the "joint" orientations. Evidence is presented from field studies in four limestone quarries supporting laboratory studies. Reasons for success and failure of widespacing technique is also provided. Only with suitable orientations of "joints: widespacing is successful.

Jan 1, 1990

Currently there are in excess of 200 companies listed on the New Zealand Stock Exchange and the total market value of all the listed shares amounts to $4.6 billion. The number of listed mining companies stands at nine and with a market value of $35 million accounts for less than one per cent of the total market capitalisation. In comparison, the Australian mining and energy sectors account for nearly 50 per cent of the total market capitalisation, which currently exceeds A$41 billion. Surprisingly the share markets in both countries were primarily founded on the discoveries of minerals last century.

Jan 1, 1982

By Lu S, Jiang Y

The conventional transportation system in open pit, a to u.* itc:,~> truck., to carry the ore along the ramps. Normally, the transportation distance increases greatly as mining progresses deeper. A new approach to overcome the above disadvantage is to adopt a buried roadway by which ores is transported by conveyors from the mining area to the outside dump in the shortest distance so that the production efficiency is greatly increased. Maintenance of the buried roadway in a good working condition is the key factor that determines the success or failure of the proposed approach. This includes the determination of support load, types and structures of support and other related supporting measures. The crucial problem here is to effectively control the load applied on the buried roadway in a certain range that the ordinary support can stand. Based on the theoretical analysis, numerical modelling and physical simulation testing using equivalent material, this paper studies effects on control of the support load by adopting certain measures, for instance reinforcing the surrounding rock and placing the extendable layer between the support and a rock mass. Furthermore, the influence of the dynamic load induced by the movement of heavy vehicles on the stability of the buried roadway is also investigated.

Jan 1, 1995

Last September, when I was asked to prepare this paper, I was told the subject was "mining," a broad subject indeed! Rather than choose one of the many important technical and economic details which characterize mining today, I turned to a subject which fas- cinates me: mining's image. If we are to survive and prosper into the twenty-first century, and if industry and society are to continue enjoying the material benefits which flow from mining, we must address the melancholy fact that the general public at best does not understand mining, and at worst does not believe it is needed or deserves to continue. While my point of view is largely that of an American mining executive, I would hasten to point out that Homestake has participated in Australian mining for over three decades, and our subsidiary, Homestake Gold of Australia Limited, is now a major producer in this "lucky country." Does society need a viable minerals and metals industry? The answer is obviously "yes," so the challenge is to change some minds: not just those of the amorphous "public," but on a focussed basis targeting journalists, educators, TV commentators, politicians and opinion makers of all stripes (I thought of using "rifle shot" instead of focussed but thought that might be misconstrued). Along the way we miners must also look deeply into ourselves, our attitudes towards the society in which we function, and our willing- ness to change as well as to seek change in others. How did we become such bad guys? More than a century ago mining was not just accepted, it was even romanticised. In America, we had altered the time-honored concept of "Crown" lands into public lands made easily available to settlers pushing back the frontier. Miners even preceded the farmers and stockmen in what was perceived as nation-building, although by the 1890s there was a growing interest in conservation, especially the protection and management of forests and national parks. Even though emphasis was shifting toward government stewardship and away from trans- fer of public lands to private ownership, homesteading and mining were clearly recognised as valid uses requiring not just access, but security of tenure. Indeed, conservation as it was then understood implied management of the public domain as well as its protection. Initially this was no great problem to the U.S. mining industry, but as the nation grew and competing land uses became more important, conflicts began to appear, first over water rights and later over air quality and destructive mining practices. But these were local disputes rather than national issues, and two World Wars, the Great Depression and post-war reconstruction lulled our industry into thinking that nothing had really changed. After the storm began to break in the 1960s, the mining industry found itself confronted by a growing maze of complex and costly laws and regulations. It took us longer than it should have to realise that, in facing this challenge, we seemed to have lost the understanding and support of many of our legislators and a majority of the general public. For over 20 years now, since the first Earth Day in 1970, the U.S. Mining

Jan 1, 1991

By C Yeung, N Swa, D Gribble, R Reupana

BlastLiteÖ is a low density explosive developed by Dyno Nobel and has been in use at BHP Billiton Iron OreÆs Mt Whaleback Operation since March 2004. The Mt Whaleback Operation utilises BlastLite because it offers an attractive alternative to ANFO in soft to medium strength rock types. Its use also reduces the amount of liquid fuel oil consumed and is well aligned with BHP BillitonÆs corporate Energy Excellence initiatives to reduce greenhouse gas emissions. This paper presents the:results of characterisation work completed on-site as a fourth year mining engineering thesis, and application and benefits of the product at Mt Whaleback. One of the key features of low density products is that the detonation is non-ideal. That is, the explosive does not react fully in the detonation driving zone. This manifests itself in that the product is highly dependent on charge diameter and confinement conditions. Dyno Nobel has access to the Vixen suite of detonation codes for characterising the ideal and non-ideal behaviour of explosives. The objectives of this work were to use the Vixen_i code to characterise the detonation performance of BlastLite, in order to understand the role of the bulking agent and to allow modelling of the explosive. The detonation performance was established by detonating a series of unconfined charges at various diameters and measuring the velocity of detonation (VoD). The work program consisted of sourcing and preparing cardboard tubes of various diameters (80 mm to 305 mm). The tubes were loaded with explosive at the BHP Billiton Iron Ore Mt Whaleback test range and detonated one at a time. Over the past three years BlastLite has been used in various applications across the site. Initial findings illustrate that shovel productivity from BlastLite shots was comparable to the baseline ANFO blasts. The study results were also backed with visual inspection and feedback from shovel operators. A work program is currently in place to develop different blends of BlastLite and TITAN« BlastLite to tailor the explosives to various blasting applications. The trials at Mt Whaleback are leading to future opportunities of BHP BillitonÆs satellite orebodies.

Jan 1, 2007

By D W. Airey

Frictional rock bolts are widely used because of their low cost. However, they have a thin wall section that makes them prone to corrosion, and they cannot be relied on to provide long-term ground support. It is difficult to assess the capacity after the bolts have been installed as they can only be pulled out if this has been allowed for during insertion. The questions of how long can the rock bolts function effectively and the effectiveness of various surface coatings, which can have significant cost implications are, investigated in this study.A series of accelerated corrosion tests have been performed on frictional rock bolts. The rock bolts, typically 900 mm long, have been inserted into concrete cylinders produced using a styrofoam insert to create the hole for the bolt insertion. Strata rock bolts with four surface coatings have been tested: uncoated black steel, galvanised, enduro (plastic coated) and coated with a proprietary aluminium/zinc alloy. Tests have been performed on two diameters of bolts. Following insertion of the bolts, the concrete cylinders were placed in a large drum filled with saltwater and current was applied to accelerate the corrosion process. The rock bolts were then extracted at various times after the commencement of corrosion. Comparison of the insertion and extraction resistances shows that corrosion initially increases the bolt resistance and that substantial section loss is required for the bolt resistance to drop significantly.CITATION:Airey, D W, 2014. Laboratory corrosion tests of frictional rock bolts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014