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By J F. Colinet, G, J A. Zimmer, R J. Timko

It has long been known that ventilation is a cost-effective method to lower respirable dust concentrations in all types of mining applications. The National Institute for Occupational Safety and Health has been working on a number of different research techniques that use ventilation as a critical component to lower respirable dust levels at surface and metal/non-metal operations in the United States. This article presents five such research efforts. The first research area discusses how improving the ventilation flow patterns in an iron ore mill facility lowered respirable dust concentrations by 31 per cent throughout the primary grinding area. The second research area examines how respirable dust levels were lowered at a dimensional stone shop by using air cleaning units suspended from the ceiling. A third area discusses how improvements in ventilation at underground limestone mines lowered respirable dust concentrations. The fourth area examines how improvements in dust filtration and pressurisation systems significantly impacted the air quality in enclosed cabs of surface mining equipment. The last area presents a newly developed clothes cleaning technique. This technique uses an air spray manifold to blow dust from a workerÆs clothing in an enclosed booth, which confines the dust for capture and removal by a baghouse dust collector. These research areas represent an array of different control technologies to lower respirable dust concentrations. Ventilation is an integral part of these control technologies.

Jan 1, 2005

By Grader F. E

A linear motor properly wound can serve as a mechanism for separating paramagnetic sulphide minerals, like pyrrhotite, from other sulphides and associated gangue minerals. The effective- ness of separation depends on the energising current of the separator, the frequency of the a.c. cycle, and the particle size of the minerals. The speed of travel of the minerals over the surface of the separator is also a function of particle size, and appears to be constant. The movement of pyrrhotite, magnetite and iron filings of comparable size fraction (150um +74pm) on the linear motor surface has been observed using a cine camera. An attempt has been made to give a theoretical basis for the movement of the particles by calculating the minimum electrical energy required to move them. Further, the rate of decay of magnetic moment of the particles has been estimated for magnetite and it has been found that sufficient residual magnetism existed in the particles after they had been exposed to the first half of an a.c. cycle for them to have like polarity with the second half of the cycle. The particles are therefore repelled from the motor surface every second half of the cycle. This repulsion due to remanent magnetism is the probable cause of particle movement over the linear meter surf, e.

Jan 1, 1980

By B Harvey

Achieving community and stakeholder endorsement during life-of-mine planning and implementation requires a business-connected approach, as opposed to charitable giving, disconnected offsets and environmental adventurism.CITATION:Harvey, B, 2014. Extractive companies, development and environmental agendas, in Proceedings Life-of-Mine 2014 , pp 19–22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Winrove G. S, Herdie G. J, McCarthy C. A

Production of hot metal from the Hlsmelt Research and Development Facility at Kwinana, Western Australia commenced in October 1993. The stand-alone facility is a unique, coal-based, integrated ironworks equipped to process iron ore fines to pig iron and simultaneously undertake a wide range of research tasks. The data generated will be used to verify the commercial potential of the technology and to set the design and operating parameters for a full-scale production plant. The design, construction, commissioning and initial operation of the HRDF has required many innovative and practical solutions to be developed and implemented by the international group of organisations contributing to the Hlsmelt Project. Initial operation has produced results which demonstrate the potential of the unique process technology associated with the core plant smelting unit. The recent achievement of post-combustion levels of 60 per cent with heat transfer efficiencies greater than 85 per cent demonstrates that the performance obtained with the Small Scale Pilot Plant in Maxhutte, Germany can be reproduced at a larger scale. The results presented in this paper support the thrust for further intensification and future commercialisation of the process.

Jan 1, 1995

By S Phinn, V Glenn, P McKenna, P D. Erskine, D Doley

The key goals for mine site rehabilitation require mine managers to demonstrate that rehabilitation is safe, stable, self-sustainable and non-polluting. Within this context, it is reasonable for stakeholders to expect that mine site rehabilitation is resilient to disturbance impacts such as fire and drought. However, mine managers actively avoid fire on rehabilitation; and as a result have limited understanding of fire behaviour on revegetated landforms, the long term implications for site stability and the potential risk to site relinquishment. An experimental fire that was conducted at the Curragh Mine site in May 2015, burnt 117 ha of 19- to 21-year old mine site rehabilitation, mimicking wildfire conditions and creating a mosaic of fire impacts across the landform. Using a combination of ground surveys and remote sensing assessments, we demonstrate that over a two year period, ecological metrics such as species richness, woody density and understorey biomass all recover to pre-fire levels for both grassland and open woodland areas. This is supported by WorldView-3 satellite imagery and the remote sensing assessment using the differenced Normalised Differenced Vegetation Index (dNDVI) which shows high regrowth within the burn area in 12- and 24-month image captures. The results suggest that within the recorded conditions, this site is resilient to fire impacts, and has the capacity to recover to pre-fire levels within the first two years following the fire.CITATION:McKenna, P, Erskine, P D, Phinn, S, Glenn, V and Doley, D, 2018. Measuring the recovery of coal mine rehabilitation following fire in Queensland using remote sensing and ground surveys, in Proceedings Life-of-Mine 2018, pp 141–146 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By H Cifuentes, D J. Williams

Despite the recognised importance of tailings management, there remain little data on the potential benefits of biological treatments compared with physical and chemical treatments. The operation of the majority of tailings storage facilities (TSFs) continues to employ mainly physical solutions, such as sub-aerial tailings slurry deposition, with increasing adoption of thickening, paste and filtration to dewater the tailings involving the addition of chemicals such as flocculants and coagulants. However, with tailings production continuing to escalate rapidly due to the increasing demand for commodities and reducing ore grades, available technologies have not demonstrated cost-effective performance at high tailings production rates. This paper examines the emerging role of bacteria to better manage tailings, reducing risks and optimising storage capacity. Bacteria have the potential to enhance tailings dewatering, maintain their permeability, delay the onset of desiccation cracking, and improve their shear strength. Bacteria-treated tailings may be suitable for use as construction materials. Bacteria also have potential in limiting the dusting of tailings and facilitating rehabilitation on closure. The paper describes a series of laboratory involving the addition of harmless bacteria to a range of tailings. The bacteria form a compact material called calcite (a common and stable form of calcium carbonate), which immobilises the tailings particles, releases water, and cements the tailings in a stable and natural matrix. The water released can be recovered or evaporated, depending on site objectives. The bacterial reactions are linked to physical and chemical processes, providing the potential for an optimal mix of technologies for particular tailings and site conditions.CITATION:Cifuentes, H and Williams, D J, 2018. Potential improvement of tailings geotechnical behaviour using bacteria, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 228–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By A B. Richards

Time window analysis that limits the explosive mass fired within a specified time window (commonly eight milliseconds) has been used for many years in blast design by explosives engineers. Despite several warnings in the past that this technique has limited practical or scientific basis and, in many cases, does not effectively control vibration, almost every textbook and blasting manual refers to time window charge mass limits as a primary vibration control technique. It has become entrenched in some blast vibration management plans, despite being inappropriate for the particular situation. With the flexible initiation timing available with electronic detonation almost a practical reality, and the 8 ms constraints in-built into the signal tube initiation system thereby lifted, it is timely to review the significance of the 8 ms time window in controlling blast vibration. This paper re-visits the original research that led to the development of the 8 ms criteria and the non-supportive conclusion of the original researcher. Because airblast was not measured, the 8 ms time window was never intended to be applicable for airblast control. Examples of blast designs are given in this paper that comply with the 8 ms time window limit that result in substantially increased air and ground vibration, together with examples of blast design that does not satisfy time window considerations, which results in reduced air and ground vibration. Techniques that identify wavefront reinforcement, due to the combined effect of drilling pattern and delay sequence, can assist explosives engineers to avoid high blast vibration situations that result from the inappropriate application of time window techniques and other adverse delay combinations.

Jan 1, 2003

By F D. I Hodgson

Twenty-seven observation test pits were excavated at four different spoils dumps at three collieries in the Witbank Coalfield. The holes were dug into the upper three metres of the spoils to ascertain if any weathering profiles, variation with age or influence of topsoil covering could be gauged. Samples from these holes were also subjected to laboratory testing (ABA, humidity cells and mineralogy on several selected samples). The test pits showed that there was a good correlation between in situ paste pH-values and ABA results for samples taken from the pits. At all the collieries, no correlation between age of spoils and in situ acidity could conclusively be drawn. The depth of soil cover also appears to be a minor consideration in determining the eventual acidity of the spoil. In the pits where acidity was found, the weathering was evident when contrasted to areas still buffered. It is unclear if the weathering leads to the acidity or vice versa, as the soil covering appeared to be similar. The spoils proved to be extremely variable with regard to particle size and material on a micro and macro scale. Evidence from most of the holes suggested that there was enough water contained in the fine material in the spoils to support the initiation of acid generation. Conclusions from this investigation are that the mineralogy of the spoils is the most important factor in determining the eventual occurrence of acidic hotspots, and that prior characterisation and selective handling will provide the best management practice for these spoils.

Jan 1, 2003

The economic viability of many Southern African massive mining operations is threatened by excessive dilution. In many operations currently in progress, some stopes are experiencing as much as 115 per cent waste ingress reporting to drawpoints. This paper examines the magnitude, causes and types of dilution and presents a set of general principles for the control of dilution in massive stoping operations.

Jan 1, 2000

By James D

Fletcher Challenge Limited through its subsidiary Grampian Mining Co Ltd has carried out an ore evaluation of one of New Zealand's largest known deposits of ilmenite located at Barrytown on the west coast of the -South Island, New Zealand.The ilmenite is located in a beach sand environment which has previously been mined for gold. Two analytical techniques were developed to quantify the resource. Considerable difficulty was experienced in this phase of the evaluation due to the presence of major inclusions within the ilmenite grains. Wet and dry concentration circuits, utilizing spiral, wet magnet, high tension and plate electrostatic separators have been G47designed to produce ilmenite from the ore. Studies to utilize the titanium content of the Barrytown ilmenite have been made. Recent work has been directed towards a titanium dioxide pigment process.

Jan 1, 1986

By D R Quick

The Goodall gold mine is located 30 km east of Adelaide River, within the Pine Creek 1:250 000 map sheet, at 8 525 000 mN: 750 000 mE, on the AMG grid. The first gold was poured in April 1988 and the mine closed in September 1993, having produced 228 400 ounces of gold from 4.095 million tons of ore, at a head grade of 1.99 g/t. Oxide and primary ore was mined from one large open cut and low grade oxide ore from three smaller pits. The gold mineralisation was discovered in 1981 by means of a helicopter borne rock chip sampling survey, which delineated 13 discrete anomalies. Systematic grid sampling of rock chips outlined an area of 1300 m by 300 m within the 2.0 g/t contour. Over 7500 m of costeaning was used to delineate the A and B-Pod mineralised areas. Geochemical soil sampling played only a minor role in the discovery and geophysics none at all. By the end of 1984, 40 diamond drill holes had been completed and a resource of 3.63 million tonnes at 3.0 g/t calculated. In January 1985, Western Mining Corporation Ltd became a joint venture partner and funded exploration to cam a 60 per cent interest. Additional drilling led to a feasibility study in 1987, based on a Measured and Indicated resource of 4.25 million tonnes at a grade of 2.35 g/t. The host rocks are quartzo-feldspathic wacke and interbedded phyllitic siltstone, of the Proterozoic Burrell Creek formation. The main zone of gold mineralisation, A-Pod, occurs in a sub-vertical vein array, up to 50 m wide and 800 m in length, of quartz and sulphide veins (5-20 mm wide), It is parallel to and on the east limb of an upright, north plunging anticline. Five types of veining have been recognised, with the bulk of the gold mineralisation associated with quartz-pyrite-arsenopyrite and chlorite-quartz-pyrite veins. The gold occurs as particles, from 1-20 micron, as inclusions and along fractures in pyrite and arsenopyrite and to a limited extent in chlorite. The mineralisation is epigenetic and structurally controlled by fractures developed during an earlier folding event. The gold is assumed to have been derived from the underlying sediments of the Koolpin Formation by hydrothermal fluids emanating from the deep seated northern margin of the Cullen Batholith. Precipitation of gold may have been controlled by variations in temperature and pressure.

Jan 1, 1994

THE question of dealing with the small quantities of copper found in a great many of the purchased ores became a factor of importance when the Sulphide Corporation decided to refine its own lead bullion, as the presence of this impurity has a marked effect on the efficiency of the de-silverizing operations of the Parkes process. Removal of the copper from the base bullion.The copper is removed from the base bullion by drossing, which collects the copper, and at the same time has considerable gold, silver, and lead values. The drassing of the bullion is done in two stages-firstly, at the smelters; and secondly, in thecopper kettles at the refinery. In both cases a "wet" dross is produced, which is subsequently "sweated" in a suitable type of furnace. When "dry" the dross is raked out and stored until enough accumulates to warrant a nUl on dross in the small blastfurnace kept for that purpose. A typical assay of the "dry" dross is as follows...WORKING THE DROSS UP TO LOW-GRADE CU-PB MATTEThe accumulated dross is treated in a small blast furnace with the necessary fiuxes, producing a low-grade Cu-Pb matte and base lead bullion.

Jan 1, 1920

By J MacDiarmid

Atlas Copco is a leading provider of industrial productivity solutions (Atlas Copco, 2007) and one of the worldÆs largest suppliers of rock drilling equipment. The business division of Atlas Copco Construction and Mining Technique is based in +rebro, Sweden with the majority of their equipment produced in a number of facilities within the area. As part of the 2006 AusIMM/Atlas Copco Scholarship I was fortunate enough to visit these facilities to experience first hand this truly unique global company. Through numerous presentations on the various divisions and products manufactured by the company, I saw the broad range of products and services offered by the company and came to realise it is much more than just selling drills. Other highlights included a brief love affair, a tour of EuropeÆs largest underground mine (or factory depending who you ask), a drink at the ice bar at the ice hotel in JukkasjSrvi, and a number of dinners of reindeer. Overall this it was a truly amazing experience with all involved with the program going out of their way to ensure I got the most out of the trip. More importantly, through no effort at all, everyone naturally conveyed their passion for the industry and the company which is a great credit to the æAtlas Copco WayÆ thereby creating a company æcommitted to your superior productivity through interaction and innovationÆ.

Jan 1, 2007

A summary of the more important work by previous workers is followed by brief descriptions of the rock formations and regional structure. Type examples of the various forms of mineralization are described and the conclusion is drawn that there has been one main period of ore formation, namely, during the "Viti Revolution" in the mid or late Miocene.INTRODUCTIONThe Crown Colony of Fiji is comprised of a group of some 250 islands situated between latitude 160 sand 21 0 S and longitudes 1770 E and 1780 w: By far the greater, part of the total area, 7,083 sq. miles, is contained within the two main islands, Viti Levu 4,053 sq. miles, and Vanua Levu 2,128 sq. miles, and it is to these that most geologists have directed their studies. The most detailed work has been in the Tavua Basin, north coast of Viti Levu, centering about the mining town of Vatukoula and the geology of this area forms the subject of a separate paper by Blatchford (this volume p. 13).The present contribution summarizes geological knowledge of Fiji, at the time of writing (Feb. 1952), with particular reference to the known mineralIzation, but excluding the Tavua Basin. For general descriptions of Fiji's topography reference should be made to the recent works of Derrick and Dunkin.PREVIOUS WORKERSPeriod 1840-1930Prior to the gold rush of the early 1930s the visiting geologists concerned themselves in the main with the struc...

Jan 1, 1953

The paper re-visits an old and proven concept of winzing, a method widely used in the past to gather exploration data for accurate definition of the orebody. It is proposed to use a mobile Supersucker (a giant vacuum cleaner also known as vacuum lift), to carry out winzing activities underground. A brief description of conventional underground winzing used in the past is provided, together with a discussion on other underground bulk exploration methods used in Australia to date. Historical background, principles of the proposed system, Supersucker construction details and productivities, and benefits and advantages of the proposed system in comparison with other exploration methods, are outlined. Other relevant applications of the mobile Supersucker, including surface winzing, are also briefly discussed in the paper. With a view of using the mobile Supersucker to recover all broken ore stocks underground, included are also results of floor sampling conducted recently in the in-stope decline excavated in a coarse gold type, high-grade orebody.

Jan 1, 2002

The radiolarian biostratigraphy of the western part of the Gympie Province, north of Brisbane, has been examined. This part of the province comprises mainly the Amamoor beds and the Gympie Group, which have been assigned Permian ages on the basis of localised marine macrofossils. This study has shown that the Amamoor beds and the Gympie Group include older strata than previously supposed.The Amamoor beds consist of at least two tectonic units, namely a melange unit (unit A) and a well stratified sequence of sedimentary rocks (unit B). The former unit, regarded as an accretionary subduction complex, contains chert blocks ranging from Late Devonian to Earliest Carboniferous, while the latter unit yields Permian radiolarians. Latest Devonian to Earliest Carboniferous bedded cherts occur in sequence previously mapped as Amamoor beds and Gympie Group.

Jan 1, 1990

By G J. Lyman

Sampling of grain for mycotoxins is challenging in that some mycotoxins, such as Ochratoxin A (OTA), have very low permitted levels and the kernels carrying the mycotoxin may be highly localised within the bulk of the grain as ‘hot spots’. Sampling for genetically modified organisms (GMOs) can be fraught with similar problems, especially if the contamination is adventitious and random. Incremental sampling under these circumstances can be shown to lead to a high variance in the sampling result.A new design of sampler for grain and other free-flowing particulates has been developed that is effective in practically eliminating the sampling variance due to distributional heterogeneity (DH).This paper introduces the design and argues that the sampler should be free of sampling variance due to DH.CITATION:Lyman, G J, 2017. A new sampler for grain and other free-flowing particulates, in Proceedings Eighth World Conference on Sampling and Blending , pp 277–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The amount of land subjected to coal surface mining in the United States has been reported at 1, 302, 000 acres (1). Latest National Coal Association estimates (1968) show that about 65, 000 acres are affected annually in the production of 186, 000, 000 tons of coal. Peabody Coal Company affects approximately 9500 acres annually in the ten States in which we are presently operating. Surface mining at Moura, Australia was begun in February 1961. In Marcy 1963, the Marion 7900 dragline with 35 cubic yard bucket went into operation and in 1967 the Marion 8900 dragline with a bucket capacity of 130 cubic yards was put into operation. In addition a third dragline, a 480W was added in 1969. It carries a 15 cubic yard bucket and is used to work areas that are too small to justify movement of the larger machines, In 1969 the Moura surface mine produced 3, 002, 774 short tons, and in 1970 3, 418, 933 short tons.

Jan 1, 1971

By Thompson M

The humble gabion basket is to mine development what the light bulb and safety pin are to eir-ryday life. Gabions provide a flexible, easy to assemble and cost efficient solution for "101" mine and civil engineering development applications.In some instances gabion baskets are still efficiently in use after many years of faithful, maintenance-free service. In other situations, the baskets have been demolished or made redundant within days, either having served their temporary usefulness or negligently destroyed by the operator of heavy equipment. Either way, the gabion basket must surely rate among the top 10 cost efficient engineering construction materials.

Jan 1, 1994

THE exceptional rainfall characteristic of the West Coast of Tasmania, in conjunction with the rugged topography of the district, has always suggested the utilization of water-power, and from the earliest days of the Mount Lyell Company theeventual installation of a hydro-electric power scheme, making use of some near-lying lake, has constantly been kept in view. At the period of the inception of the company, however, the time was not ripe for such an undertaking, and it is only oflate that the various important considerations involved have sanctioned incun;ing the heavy expenditure necessary, with the positive assurance of permanently reaping the benefits expected. The West Coast of Tasmania contains many lakes of varioussites; situated at high levels, and, although the catchments of these lakes are not very extensive, still, the excessive rainfall is so constant over long periods that its regularity may be relied on as offsetting the limited catchments. The explanation of the abnormal rainfall is simply the circumstance that the West Coast Range forms the first high land barrier which is met by the moisture-laden westerly and north-westerly winds blowing off the Southern Ocean. By the time the clouds strike the mountains they ride very low, consequently the elevation of the range, the peaks of which do not exceed 3000 to 4000 ft. above the sea, is sufficient to cause a copious precipitation. Lake Margaret, which is situated five miles north of the reduction works, was first recognized as a possible source of waterpower by Mr. Hugh Ohrisp, a surveyor, who visited it about 1893-4. Earlyl in 1895, while the preliminary work on the erection of the first furnaces of the Mount Lyell Co.'s reduction...

Jan 1, 1915