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By J. M. Schaekers

In the first part of the article, the authors give a broad overview of the chemistry and some engineering aspects of bioleach processes, eventually leading to the important and critical issue of the stability of arsenic-containing residues, especially those derived from bioleaching of sulphidic gold ores. In the section ?Factors affecting arsenic stability? they give an excellent summary of the factors normally affecting the stability of such residues. This is followed by some valid comments on the suitability of a single leach test to evaluate the long-term stability of solid waste streams. However, they fail to mention that, up till now, no tests procedure has been accepted by either environmentalists or the mining/processing industry as a valid method to test the long-term stability of solid wastes. Their own method is no exception, although, like many others, it is useful to identify potential problems with solid wastes considered for disposal.

Jan 1, 2001

By Parviz F. Rad

This Bureau of Mines report reviews laboratory and in-mine techniques for determining mechanical properties of coals, with special emphasis on the relationship between these properties and the minability of coal. An extensive bibliography is included.

Jan 1, 1973

By Bernard H. Hertlein

Transportation system structures have come under very close scrutiny in the last couple of years, largely due to the damaging effects of disasters, both natural and man-made. In the Pacific northwest and California, earthquake risk is a major concern. In the central and eastern states barge impacts on bridge piers and docks are a big worry. In all cases of bridges over water and waterside structures, scour is a primary concern. Some of the results of this scrutiny have been changes in design and construction methods, and the introduction of more testing to supplement field inspection during construction, and throughout the service life of the structure. Future construction of bridges and docks will almost certainly see a continuing growth in these practices. Where foundations are concerned, particularly for bridges and waterside structures, many state and local authorities have started specifying drilled shafts rather than driven piles. Where the shafts must be constructed under water or slurry, visual inspection of most of the work is impossible, and one of several different Nondestructive Tests (NDT) is often specified. Contractors' experiences with these methods have varied considerably, and there is a great deal of controversy in the deep foundation industry over the reliability of NDT methods for assessing the integrity of foundation shafts or piles. The author has had more than 15 years of practice with the various NDT methods for deep foundations, on projects all over the US, particularly foundations for bridges and dock structures, and has developed an understanding of the "NDT controversy" as it has become known. In particular, experiences in the Pacific Northwest, California, and Alabama have illustrated the reasons for the controversy. This paper reviews these experiences, and suggests some steps that owners and contractors can take to reduce the risk of inconclusive or downright inaccurate test results.

Jan 1, 1998

By Yingxin Zhou

Virtually every coal seam in Appalachia will at some time be subject to multi-seam interaction (Wu et al, 1987). Many such problems result from seams which lie in close proximity or have split and lie within thirty feet vertically of one another. Existing techniques for multi- seam design have concentrated on conditions where the entire inner burden is not the failing member and are unsuitable for ultra-close multi-seam design. Structural integrity of the inner burden must be maintained if two superimposed seams are to be mined separately and under- standing possible failure mechanisms of the inner burden is an essential first step in the design process.

Jan 1, 1989

By N. Kornelius

In recent years there has been an increased focus on corporate governance matters worldwide. The duties and responsibilities of directors of companies have come under close scrutiny, with shareholders increasing their demands for greater responsibility and accountability. Media attention and pressure groups have also had their effect. Governmental actions have supported these demands and directors have witnessed sweeping legislative changes imposing more onerous duties and liabilities than formerly imposed upon them at common law and in terms of the Companies Act. At the same time, the power of regulatory bodies has been increased to enforce this legislation and make someone pay to remedy an alleged infringement. Breach of such duties may incur personal or criminal liability, or both. Environmental protection legislation has become a particularly prevalent feature in this regard, and the number and complexity of statutes concerning the environment have increased over the past few years. Directors of South African companies will be familiar with relevant acts such as the National Environmental Management Act 107 of 1998; Conservation of Agricultural Resources Act 43 of 1983;Hazardous Substances Act 15 of 1973, as well as the National Water Act 36 of 1998. Now the directors of mining companies are faced with the Mineral and Petroleum Resources Development Act 28 of 2002.

Jan 1, 2003

By V. D. del Valle, T. G. Joseph, J. J. Berezan

Aggressive driving patterns, rough and poorly maintained roads and pit floors, along with the occasional bump and poorly placed load from a shovel can create intense and sometimes serious vibration levels on a heavy hauler. The effects of high vibration have been shown to be of concern for the health of the operator as well as the reliability of the equipment. It is proposed that an onboard vibration warning system based on the ISO 2631-1 standard could be used to help operators reduce the vibration levels experienced in a heavy hauler. The onboard system would consist of a screen that displays the instantaneous vibration in the form of three lights: green (safe zone), yellow (cautious zone), and red (danger zone), as well as an overall vibration exposure or dose for the entire shift. With the utilization of the warning system, it is anticipated that the overall vibration levels will be decreased resulting in improved operator health, a reduction of vibration-induced maintenance, and improved haul roads through reduced impact loading and repair for localized trouble areas.

Jan 1, 2004

By Shemek Oginski

The 5 km (16,194 lf) of 6.1m (20 ft) diameter TBM driven tunnel built by the J.F.Shea Co. will serve as sewage overflow storage. The TBM tunnel and four connecting tunnels excavated by drill and blast methods in hard granite will remain unlined. Based on the Geotechnical Baseline Report (GBR), the Contract documents provided a design with no required pattern of rock bolts, no probing, no pre-excavation or consolidation grouting, and lastly, no final lining of the tunnels was deemed necessary. This paper will provide a general overview of these topics with the emphasis on the actual ground conditions encountered versus the projected conditions provided in the GBR and how the GBR reflected the design of the project. Proposed modifications to the temporary and permanent ground support will be presented and the necessity of probing and pre-excavation grouting will be evaluated.

Jan 1, 2005

By J. Shawn Peterson, David S. Yantek, Adam K. Smith

Occupational noise-induced hearing loss continues to be one of the most pervasive health problems in the mining industry, despite over 25 years of regulation. One of the loudest pieces of equipment used in underground mining is the continuous mining machine. Noise sample data collected by the Mine Safety and Health Administration indicate that 42% of noise overexposures between 2000 and 2005 involved continuous mining machine operators. Previously conducted field and laboratory tests have determined that the continuous mining machine conveyor system is a dominant noise source. Loud impacts occur as the conveyor chain flight bars, used to move the mined aggregate, traverse their path from the top to the underside of the conveyor deck. Various noise control treatments have been applied to abate noise caused by the conveyor system. A durable polyurethane coating has been developed for the conveyor flight bars, resulting in a time-weighted average reduction of 3 dB(A) for an eight-hour work shift. In an attempt to further reduce continuous mining machine operator overexposures, a similar urethane coating has been applied to the tail roller component of the conveyor system. Laboratory results showed a 2 dB(A) reduction in sound power levels, but the component failed during underground durability testing. An outer steel sleeve has been added to the urethane coating of the tail roller to enhance wear resistance during mining. The urethane jacketed tail roller is the latest effort, combined with previous noise treatments, to bring the continuous mining machine into compliance with federal noise regulations.

By H. Wagner

During the last few years a large number of pillars in different mines were investigated. Pillar conditions were evaluated using subjective, empirical, geophysical and numerical methods. A critical comparison of the different methods showed some interesting coherence. This paper concentrates on experiences using the p-wave velocities as an indicator of pillar conditions. Während den letzten Jahren wurde eine große Anzahl von Bergfesten in verschiedenen Bergwerken auf ihren Zustand hin untersucht. Hierzu wurden subjektive, empirische, geophysikalische sowie numerische Methoden angewandt. Dieser Vortrag beschäftigt sich mit den Erfahrungen beim Einsatz der p-Wellengeschwindigkeit zur Beschreibung des Festenzustandes. Le condition géotechnique d’une grand nombre des piliers des mines souterraines différentes sont examinées ces dernières années. On a appliqué des méthodes subjectives, empiriques, géophysiques et numériques. Ce rapport occupe aux expériences avec l’application de la vélocité des ondes de compression pour tracer le condition des piliers.

Jan 1, 2003

To provide a faster means to open and close permissible electrical enclosures. Approach: An inspection and repair port with a multiple start thread which provides a permissible joint has been developed and tested. How It Works: The inspection port screw thread has a large pitch, which allows the port cover to be rotated from fully closed 10 fully open, in less than one revolution. See Figure 1. When the cover is screwed back in. it be-gins engagement within one eighth turn because the screw design has eight separate threads. To prevent Its unauthorized opening, the port cover has a bolt guarded by ears which accept a padlock. The threads are designed to tolerate a reasonable amount of grit without binding, although wipe-off cleanness is necessary during reassembly. Enclosures of two different sizes each fitted with the quick-access port, were

Jan 1, 1976

By A D. Stewart Gillies

Resource rent taxes are taxes which only become effective at such a time as a pre-determined rate of return has been achieved by an operation. Resource Rent Taxes have from time to time been considered for implementation in bothAustralia and New Zealand. The offshore petroleum industry in Australia is already subject to RRT as is the Roxby Downs (Olympic Dam) Mine in South Australia. Both the mining and petroleum taxation regimes in Papua New Guinea include a resource rent tax component called Additional Profits Tax.   The implications of the current form of additional profits tax for shareholder cash returns are that the tax burden on the operation may suddenly increase at some stage in the life of the mine if and when the threshold level of profitability for the tax to be triggered is exceeded. From that point in time onwards the cash return to the shareholders on the capital invested is greatly diminished. For mining companies in Papua New Guinea, the effective tax rate increases from 35% to 57.75% as a result of the onset of additional profits tax. This tax rate penalty is so severe that there appears to be merit in considering the concept of managing profitability through time rather than purely maximising annual pre-tax profits as is currently the case in most mining operations. This would have the benefit of deferring or perhaps preventing altogether the onset of the tax. One possible method for the effective management of profitability is through the control of average mining grade by cutoff grade manipulation.   Traditional cutoff grade theory has usually considered taxation as a direct cost at a fixed or variable percentage of annual profits. As a result of this most analyses are conducted on a pre-tax basis. If tax is included in analyses it is usually present as a time independent function of gross profit. Additional profits tax is both time, and rate of return dependent and therefore not adequately accommodated by currently accepted cutoff grade theory.   A review has been made of the effects of resource rent taxes on both the investment decision-making process as well as possible development and mining strategies which may be employed by mining companies faced with resource rent taxes. The review includes examples based on the structure of additional profits tax which is levied in Papua New Guinea.

Jan 1, 1995

This report is the 25th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations, and the 7th of these reports to be issued on a calendar-year basis.3 It reviews briefly work in progress during 1960, and furnishes references to publications by Bureau personnel during 1960 and also to a few older papers that were not cited in prior reports of this series. Details about some of the researches mentioned can be found by referring to the publications cited in the footnotes or in the further list in the Miscellaneous section; other phases of work are reported here for the first time and will be covered in more detail by later publications, Coal programs of the Bureau of Mines extend over the wide range of theoretical and applied studies indicated by the table of contents. Fundamental research on coal structure and on the properties of coal will, over a period of time, increase the general knowledge about coal Which scientists and engineers may use in answering practical questions and in solving problems in the mining and utilization of coal. More applied studies are conducted in connection with the developement and evaluation of new mining techniques and the effective processing and utilization of coal and of coal products. Health and safety activities, analyses of coal being mined, and technical advice and assistance to Federal agencies in connection with fuel and boiler-water problems are among the practical services handled by the Bureau.4 5

Jan 1, 1962

Remote sensing, in general, is the recording of light and heat from a planet's surface within a certain range of the electromagnetic spectrum. For the Earth, systems capable of this recording are the MultiSpectral Scanner (MSS) and SLAR. The former is the recording system used in satellite and will be discussed in the next section. SLAR stands for Side Looking Airborne Radar. This device sends invisible radar waves which illuminate the Earth's surface. The reflected waves are subsequently recorded as images. The system can operate through darkness and dense cloud cover, and is particularly suited for the study of geological structures at both large and small scale (Wayland 1976). Remote sensing techniques are now widely being made use of in mineral exploration, especially for those last remote 'sanctuaries' where geological data are meagre or non-existent. For places like Borneo, West Irian, the Amazon Basin etc. remote sensing, in the form of both satellite imagery and SLAR, is of considerable help, in fact more often than not the only help, to delineate geological provinces, geotectonic domains and meaningful lineaments. In the case of New Zealand, well made geological maps at scale 1:250 000 by the Geological Survey are available to the public and these provide useful preliminary grounds for the selection of target areas. However, even in this case LANDSAT imagery can be of aid as will be shown later.

Jan 1, 1977

By H. Pei

PZH (Pan Zhi Hua) Iron and Steel (Group) Corporation, the biggest steel company in southwest China, has been using titanium-vanadium-magnetite as the main raw materials for blast furnace iron making processing for over 30 years. One of the problems that has a negative affect on the blast furnace operation is slag foaming. Based on the chemical components of the blast furnace slag-bearing higher TiO2, the foaming properties were studied. The TiO2content, which is calculated according to the total titanium content in all the forms of titanium compound in the slag, in this research is 30% weight per cent. Different forms of titanium compounds have different actions on the slag foaming behaviour that depends on the reduction condition in the blast furnace. The relationships among slag foaming performance and the binary alkalinity of the slag, the content of CaF2, MnO in slag, and the amount of gas injected in slag are investigated. The results show CaF2 and MnO have a stronger anti-foaming affect on the slag, even in the lower percentage. The way to measure high TiO2slag foaming performance and how to eliminate foamy slag are also discussed. Keywords: blast furnace slag bearing TiO2, foamy slag, foaming performance

Jan 1, 2004

By V Cullinan, D Buchanan

The Brunswick plant is located in Costerfield, approximately 40km east of Bendigo in central Victoria. Crushing, grinding, gravity gold concentration and flotation methods are used to produce a saleable gold concentrate and an antimony-gold flotation concentrate. This paper discusses the improvements made within the processing plant which have resulted in a 99% increase in throughput over nameplate capacity of 6 250 average tonnes per month to 12 445 average tonnes per month and increases of 12% gold (from 2007 average of 78% to 2014 average of 90%) and 16% antimony recovery (from 2007 average of 79% to 2015 average of 95%). This combined effort has resulted in an increase of equivalent gold ounces (AuEq oz) produced from 2010-2014 of 15 872 to 82 574 – a 66 702 increase.AuEq oz= Au oz +Sb t × Sb (US$/t)Au (US$/oz)CITATION:Buchanan, D and Cullinan, V, 2015. Improvements in bi-metal production at the Brunswick Plant, Costerfield, in Proceedings MetPlant 2015, pp 267–272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Syd S. Peng

Mountaintop removal (MTR) mining started in West Virginia nearly 30 years ago. This surface mining method can extract multiple coal seams as thin as a few inches in whole and minimum rock dilution in very steep mountainous terrain. MTR is highly efficient, even if coal seams are in close proximity and small in a real extent. Consequently, MTR has been widely used in the Central Appalachian coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impact on the surrounding area. During the past two years, however, the debate over MTR mining has grown quickly and has become very intense. This article describes chronologically issues raised by various parties, legal actions, impacts on mining permit applications and research projects developed to address the issues.

Jan 1, 2000

By Geraldine Woods

I work for the State of Washington as an Explosives inspector. My paper will describe the mission of the Wa. State Dept. of Labor pertaining to explosives and the regulation of explosives in the State.Blasting safety is high on the public safety list and the regulation of explosive use and storage has been mandated through legislature. The Dept. considers pro-active partnering forexplosive safety preferable to after-the-fact citations for non-compliance.In some cases, the Dept. will issue civil citations with monetary penalties, meant to be a deterrant, of course, to blasters who choose not to comply with the explosive regulations of the State.The Dept. has also revoked and suspended blasting licenses. In some instances, the Dept. has allowed recipients of citations with monetary penalties to reduce the amount paid by attending technical training classes. The idea here, is to reduce the chance of reoccurence of unsafe blasting practices. The State of Washington partners with MSHA in the regulation of explosives use and storage in mines, pits and quarries in the Stateas well as working closely with law enforcement, State and local fire marshals, ATF,and is active in ISEE in part of it’s ongoing effort to promote explosive safety and establish communications in a nonadversarial way with explosives users. My paper will include some statistics on licensing in the State, pounds of explosives used, inspection numbers, numbers and types of complaints with information from the inspections resulting of these complaints. My paper will include examples of storage, both good and bad, examples and pictures of fly rock incidents, accidents, near-miss close calls, break-ins, thefts, and abandoned explosives. This paper may also include a brief summary of my opinion of explosive regulation and my job as a regulator, including examples of high and low points of the job, joys and frustrations.

Jan 1, 2002

By J. Kretschmann, N. Nguyen

"The Vietnamese economic growth of more than 5% per year leads this country to an enormous demand for raw materials. In the duration of ongoing expansion, the big challenge in the coming decades will be to make this process as sustainable as possible when it comes to economic, environmental and social objectives. Risk management especially in occupational safety and health (OSH) in enterprises is one of the most important tools to achieve this aim. But until now, this has not been taken into priority by Vietnamese coal mining enterprises. Main reasons for this situation can be found in deficient legislative conditions and in non-synchronized risk management systems. In contrast, Germany has implemented an adequate legal system and the German mining industry has gained lots of experiences in risk management, especially in occupational safety and health. This paper seeks to point out specific challenges how to improve occupational safety and health in Vietnam by transferring and applying German methods and standards."

Jan 1, 2011

By Tetsuo Yamazaki

Metal market prices rose drastically in 2006, and most broke historical records as shown in Figs. 1-4. This increase has been basically driven by economic growth in Asian countries, especially China. The growth trend is expected to continue for several years. Then, India will follow the same growth trend. Their metal demands keep the price levels high for 20 years or more. One more additional important factor on the metal market prices is hedge funds come into the market. Japan imports all metals for domestic use from overseas. The amounts imported were 1.27 million tons in copper, 0.32 million tons in lead, 0.59 million tons in zinc, 0.20 million tons in nickel, and 1.18 million tons in manganese, respectively in 2006 (Source: http://www.jogmec.go.jp/j_resourse/index.html#03). Though mainly we import the concentrates and our domestic customer smelters take the part of metallurgical leaching, the payment necessary for purchasing the concentrates is estimated about US$ 10 billions in 2006. The payments in 2005 and in 2003 were about a half and a quarter of the 2006, respectively. Japan must have effective counter measures to reduce the future payments.

Sep 24, 2006

By Wolfgang Van Hooff

Encouraged by a strongly growing and evolving market for granulated products, Paul Wurth continuously improves its granulation and dewatering technologies to provide customers with state of the art installations. Continuously developed know-how about the granulation process of iron blast furnace slag enabled application to non-ferrous materials such as Ni-Slag, Pb-Slag, Blister Copper, Cu-Matte and even TiO2-Slag, which rank among the most difficult materials to granulate. This paper identifies how critical objectives in granulation and dewatering technologies applied to different molten materials with respect to various product quality objectives can be addressed. The differences between hot and cold water granulation systems are explained, including the step from cold runner to granulation water tank. Development of a flow and pressure controlled blowing box is the latest step to optimize the granulation process in order to meet the latest standards in terms of quality, power consumption and environmental protection.

Jan 1, 2006