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By Peter N. Holtham, Geoffrey J. Lyman, Matthew S. Brennan, Vijay Subramanian, Rui X. Rong, Tim Napier-Munn

Studies of the dense medium and classifying cyclone have been conducted using the Fluent computational fluid dynamics code. Experimental measurements of the segregation of medium in a DM cyclone by gamma-ray tomography and the performance of a novel classifying cyclone design have been used to test and interpret the 3D CFD predictions. The predictions of the CFD models were generally plausible, though more work is required to incorporate turbulent mixing of the slurry in the cyclone. The benefits of the novel cyclone design were explained by the model in terms of conditions favouring reduction of short-circuiting at the vortex finder, and the removal of the air core from the wall at the apex. Work is continuing.

Jan 1, 2003

By W. A. Lang

Introduction In this review, which is the fifth of the series on the Progress in Coal Technology, an attempt has been made to outline some of the more important developments that have taken place in coal carbonization during the last decade. Research into both high-and low-temperature carbonization has been active for three principal reasons: (1) the growing shortages in most countries of high-quality coking coals; (2) the demand for smokeless fuels for domestic purposes; (3) the need for metallurgical coke for the increased output of steel in the post-war years. The growing importance of coal tars as a source of chemicals for the preparation of synthetic products and of coal gases for the recovery of sulphur is evident. Many of the researches initiated because of wartime necessity have been continued .and even expanded in the post-war years. High-temperature carbonization with a suitable coal yields a strong coke which is used primarily for metallurgical purposes, a tar with good marketable value, and a large yield of gas of medium calorific value. Low-temperature carbonization gives a more free-burning solid product suitable for a domestic fuel, a high yield of a tar which is generally regarded as superior to high-temperature tar for chemical purposes, and a smaller yield of a higher-heat-value gas.

Jan 1, 1951

Well designed and maintained haul roads are the key to minimizing truck haulage on-road hazards and costs, as well as increasing productivity. However, practically designing and managing a haul road for optimal performance is often difficult to achieve. Poorly designed and built roads exhibit high rolling resistance - a 1% increase in road rolling resistance can typically reduce speed on ramp by as much as 10% - and on the flat by up to 26%. In the current economic climate, investment and operating decisions come under scrutiny. In the long run, this scrutiny returns improved efficiencies and leaner, healthier operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations ? simply by virtue of their contribution to overall cost of operations ? often in excess of 50% of total costs for deep open-pit mines. Whilst the end result - improved efficiency and reduced cost per ton hauled ? is not in itself problematic, it is the route, or process followed to achieve these savings that needs to be carefully managed. We can be guided on this journey by our understanding of how a road design is developed, and, critically, the interplay between a good design and safe, cost efficient haulage. This paper briefly summarizes the evolution of mine haul road design, from the seminal USBM work of Kaufman and Ault in 1977, through to current geometric, structural, functional and maintenance management design components. These augmented design and management guidelines have been developed over the past decade, both in response to the requirements of mine operators for more safe and efficient haulage systems, and the truck manufacturers? requirements for a more predictable and controlled operating environment. These developments have been paralleled by the need to minimize haulage hazards, both from a health and safety perspective. Whilst improved mine haul road design does indeed reduce haulage accidents, recognition also needs to be given to human factors which are a significant contributor to haulage accidents. The human factor is the most problematic to address in a road design. It is often easier break the link between the interactive effects which may lead to accidents than trying to predict and reduce human error. These human factor interactive effects include the geometric, structural and functional design components and to prevent an accident or reduce the severity of its consequences, a road should be more accommodating to human error. The more that is known about human error, the better a road can be designed to accommodate those actions or non-standard practices that would, on a poorly designed road, invariably escalate an error into an accident.

Jan 1, 2010

By Charles Will Wright

This paper has been written to aid the owner of a small gold mine or prospect in preparing a report on his property for the purpose of interesting capital. If an owner can afford to do so, he should employ a mining engineer of recognized standing and experience to examine and report on his property, but many owners of small -mines and particularly of prospects cannot make the expenditure required for this. Further, many of them do not know how to prepare a description which will cover those features of a deposit on which a potential investor promises his opinion as to its worth. If such an owner is convinced that he possesses an orebody of sufficient grade and size to warrant the required expenditure for a thorough investigation and wishes to present his property to prospective investors, then the following suggestions concerning the proper way to sample his deposit, estimate the tonnage of developed and probable ore, and prepare a report may be of assistance.

Jan 1, 1933

By R. I. Cavanagh, A J. Last

THE USE of higher grade charges in blast furnaces in the form of sintered or pelletized concentrates has been increasing rapidly. The question of beneficiation of iron ores for this purpose is therefore receiving much attention as more deposits are developed. Many iron ores may respond well to magnetic roasting procedures followed by magnetic concentration, however, in most cases other more standard ore dressing methods are competitive and cheaper. For magnetic roasting as applied to iron ore beneficiation, the present question is "Can it be economically justified in situations where it appears to produce good results?" The following collection of information on the general status and operations of magnetic roasting methods may be helpful in considering this question. Magnetic Roasting Magnetic roasting involves the transformation of non-magnetic iron oxides, hydrated oxides and carbonates by means of heat and suitable

Jan 1, 1961

By P. N. Anyalebechi

The effects of a cross-hatched grooved mold surface topography, casting speed, and superheat on the morphology of solidifying shells of aluminum alloy 3003 have been characterized by a series of immersion tests. The cross-hatched grooves were 0.232 mm deep with wavelength or spacing between 1 mm and 15 mm. The shells solidified at casting speed of less than 10 mm/s on the 1 mm spaced cross-hatched grooved mold surface were fairly uniform with little or no localized variations in thickness. However, the propensity for non-uniform shell growth morphology was exacerbated by an increase in casting speed, melt superheat, and the wavelength of the cross-hatched grooves. This is provisionally attributed to their effects on interfacial heat transfer and wetting of the mold surface by the molten metal.

Jan 1, 2008

By W. A. Grosh

The Piquette Mining and Milling Co, operates a zinc mine and concentrating mill in the Upper Mississippi Valley zinc-lead district near Tennyson, Wis. The principal ore mineral is zinc sulfide, which occurs in limestones and dolomites of the Decorah formation. Exploration in the district is by churn drilling from the surface. An adit at the base of the ore zone provides access to the mine. A room-and- pillar mining method with irregular pillars is used. Drilling is done with Jumbo-mounted drills. The broken ore is loaded by crawler-mounted front-end loaders into diesel-powered trucks for haulage direct to the mill.

Jan 1, 1959

By A. Gupta, F. Hrach, L. R. Mendoza, K. Flynn

ST Equipment & Technology LLC (STET) has developed a novel processing system based on tribo-electrostatic belt separation that provides the mineral processing industry a means to beneficiate fine materials with an energy-efficient and entirely dry technology. In contrast to other electrostatic separation processes that are typically limited to particles >75μm in size, the STET triboelectric belt separator is suited for separation of very fine (<1μm) to moderately coarse (500μm) particles, with very high throughput. The STET tribo-electrostatic technology has been used to process and commercially separate a wide range of industrial minerals and other dry granular powders. Here, bench-scale results are presented on the beneficiation of low-grade Fe ore fines using STET belt separation process. Bench-scale testing demonstrated the capability of the STET technology to simultaneously recover Fe and reject 2 from itabirite ore with a D50 of 60μm and ultrafine Fe ore tailings with a D50 of 20μm.The STET technology is presented as an alternative to beneficiate Fe ore fines that could not be successfully treated via traditional flowsheet circuits due to their granulometry and mineralogy. INTRODUCTION Iron ore is the fourth most common element in earth’s crust [1]. Iron is essential to steel manufacturing and therefore an essential material for global economic development [1-2]. Iron is also widely used in construction and the manufacturing of vehicles [3]. Most of iron ore resources are composed of metamorphosed banded iron formations (BIF) in which iron is commonly found in the form of oxides, hydroxides and to a lesser extent carbonates [4-5]. A particular type of iron formations with higher carbonate contents are dolomitic itabirites which are a product of the dolomitization and metamorphism of BIF deposits [6]. The largest iron ore deposits in the world can be found in Australia, China, Canada, Ukraine, India and Brazil [5]. The chemical composition of iron ores has an apparent wide range in chemical composition especially for Fe content and associated gangue minerals [1]. Major iron minerals associated with most of the iron ores are hematite, goethite, limonite and magnetite [1,5]. The main contaminants in iron ores are 2 and Al2O3 [1,5,7]. The typical silica and alumina bearing minerals present in iron ores are quartz, kaolinite, gibbsite, diaspore and corundum. Of these it is often observed that quartz is the mean silica bearing mineral and kaolinite and gibbsite are the two-main alumina bearing minerals [7]. Iron ore extraction is mainly performed through open pit mining operations, resulting in significant tailings generation [2]. The iron ore production system usually involves three stages: mining, processing and pelletizing activities. Of these, processing ensures that an adequate iron grade and chemistry is achieved prior to the pelletizing stage. Processing includes crushing, classification, milling and concentration aiming at increasing the iron content while reducing the amount of gangue minerals [1-2]. Each mineral deposit has its own unique characteristics with respect to iron and gangue bearing minerals, and therefore it requires a different concentration technique [7].

Jan 1, 2019

By G. P. Contractor

Medium and low carbon steels, modified with uranium, were studied in order to evaluate the influence of uranium on forge ability, mechanical 11roperties, response to heat treatment and microstructure. Uranium contents ranged up to 0.70 per cent. The medium carbon steels are hot short if the uranium content exceeds about 0.35 per cent. More uranium can be tolerated in low carbon steels. The hot shortness is caused by the formation of intergranular phase UFe2. Critical transformation temperatures, Jominy hardenability, and resistance to tempering are not significantly affected by the 11resence of uranium. Similarly, uranium has little or no effect on the tensile properties of carbon steels. The addition of uranium has a favourable effect 11n the stress-rupture characteristics and some beneficial effect on fatigue properties. However, more results are required for verification. In the steels investigated, it seems that most of the uranium carbide combines to form complex inclusions of U (0, C, N) or (C, N), rich in oxygen or nitrogen or both.

Jan 1, 1963

By Rob Thomas

"In Australia, a wide roadway is commonly defined as any roadway that is driven to a width greater than 5.5 m (18 ft). These roadways are typically required to enable the installation of longwall equipment (termed installation roads); however, other applications include the need to house conveyor driveheads and pre-driven recovery roads.As a result of the increasing size of longwall equipment and mine infrastructure, in some mines, roadway widths of between 9 and 12 m (30 and 39 ft) and are being developed.Accepting that these almost always constitute strategically important and often long-term roadways, this paper considers the use of: (i) an empirical roof support design model, which is based on over one hundred case histories, (ii) various roof support design principles, and (iii) commonly accepted strata management techniques.The paper demonstrates that wide roadways can be driven and supported to an acceptable standard providing due consideration is given to the prevailing ground conditions (including the quality of the immediate and upper roof strata, the Depth of Cover and the horizontal stressfield), the final width of the roadway and the required use of the roadway.INTRODUCTIONRoof behaviour and the associated roof support requirements in wide roadways, which are roadways typically driven to a width that is greater than 5.5 m (18 ft), are controlled by a number of key geotechnical and operational factors. The recognition of these factors is an important first step in the design process and it is imperative that each is considered in conjunction with local mine site information.The main points of note in this regard can be summarised as follows:• The greater the final width of the roadway, the greater the resulting surge in roof displacement on widening - note: a) see Figure 1 for a schematic illustration of the roof displacement trends typically measured during the development of the first pass and roadway widening, b) since displacement increases with roadway width, it is always recommended that the roadway width is kept to the minimum required and c) general buckling beam theory indicates that the capacity of any beams present in the roof will reduce in inverse proportion to any increase in roadway width squared (i.e., [final width2 -first pass width2] I final width2)."

Jan 1, 2010

By E. G. Erspamer

Laboratory investigations were made by the Bureau of Mines on ore containing the sulfides of both mercury and antimony to develop a method or methods for the economic recovery of mercury metal and the concurrent recovery of antimony as metal or salts,. If standard mercury-recovery techniques are applied to such ores, the antimony content interferes with the effective production of mercury metal; further-more, the antimony is lost. This report presents the results of tests on a sample of cinnabar-stibnite ore from the Red Devil mine near Sleitmute, Alaska. Red Devil ore was chosen for the investigation because it is purported to be typical of ores of the Kuskokwim River area, which, in their aggregate, constitute large potential reserves of mercury and antimony. Studies included petrographic, spectrographic, and chemical analyses, gravity-separation tests, bulk flotation of mercury and antimony sulfides, differential flotation, leaching, and furnacing of crude ore and of flotation concentrate.

Jan 1, 1956

By J. F. Smith

A series of studies of emissions from large coal-fired steam generators have included measurements of the concentrations of oxides of sulfur and oxides of notrogen. The sampling equipment, method of sampling, and analytical techniques used for processing of these samples are detailed. A method based on the precipitation of benzidine sulfate was developed for determining both SO3 and total oxides of sulfur in the presence of interfering acidic components in the stack gases. In addition, difficulties encountered with sampling and analytical techniques are also described.

Jan 1, 1968

By Brian Raymond

This paper will outline the problems and solutions of the new generation washeries, as well as the recent technological advances which are being considered for future coal preparation plants. The subjects to be covered will include: - reasons for considering coal preparation plants; - raw coal crushing and handling systems; - types of coal cleaning equipment being used versus new equipment being considered; - fine coal circuit sizing; - clean coal centrifuging and dewatering; - thermal dryer problems and changes; - fine refuse dewatering systems; - clean coal storage problems and changes; - materials handling within the plants; and - control systems for preparation plants. The design and integration of the various circuits that form a modern coal preparation plant have led to the creation of an exciting new field of industrial research. As the need for energy sources increases, efficient methods of preparing coals for specific markets will become more important.

Jan 1, 1979

By A. M. Esteves

This paper offers an overview of local content policies and practice in the mining sector. Specifically, the paper aims to answer the question of how national and regional governments, industry and civil society can work together to seek an optimal outcome while pursuing their diverse objectives. The paper begins by defining local content and its scope at the subnational level. Specific recommendations for the design of local content policies to mitigate social, economic and governance risks are developed. The document then offers some recommendations regarding the role of partners in design, implementation, monitoring, and enforcement of local content policies.

Aug 1, 2013

By P Gehrke, S O’Gorman

The precise measurement of NO2 was historically difficult in road tunnels, hence criteria and design analysis was based on converting from NOx concentrations via a set NO2:NOx ratio. The reliable direct measurement of NO2 is now possible, however design analysis is still dominated by emissions tables and formulas specified in terms of NOx. For converting from NOx to NO2 in a road tunnel environment in Australia, the ratio has typically been assumed to be ten?per?cent. This has generally been based on the recommendation in PIARC (2000) and on the ‘average’ value cited in PIARC (1995).Determining this ratio is important as changes in engine technology and in-tunnel pollution criteria along with improvements in CO and particulate emissions control, may mean that NO2 will become the driving factor for future ventilation requirements. Correct selection of this ratio can directly impact the ventilation capacity and system design.Recent research has indicated that choosing a constant ratio of ten?per?cent for all tunnels may not be appropriate. The in-tunnel ratio has been estimated to be as much as 20?per?cent to 30?per?cent and depends on the location in the tunnel, the type of ventilation system and the traffic/fleet characteristics. This paper discusses the effect of some of these parameters on the NO2:NOx ratio in road tunnels.The findings indicate that the ten?per?cent upper limit on the NO2:NOx ratio in PIARC (2000) may be a conservative value for design purposes for longitudinally ventilated road tunnels of typical length in Australia. A value of seven?per?cent to eight?per?cent may be more appropriate in some circumstances. However, the value chosen will depend on the specific tunnel in question and the confidence in traffic conditions expected. Values above ten?per?cent may be encountered for short periods but usually when the NO2 levels are low.CITATION:O’Gorman, S and Gehrke, P, 2014. NO2:NOx ratios in Australian road tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 95–102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K Edwards, A J. J Mouton

Hematite represents the vast majority of iron ore exported from Australia as the development and processing cost of magnetite is generally seen as a barrier to the development of vast magnetite resources. However, a number of magnetite projects have attracted a significant amount of interest and investment from large Chinese steelmakers.This paper compares the relative merits of the development of Australian magnetite and hematite ore from the point of view of the steelmaker, taking into account the factors that influence the capital costs of the development of the ore types and the relative costs of operating the process plants to treat these ores. By modelling the relative operating cost for the production of hot rolled coil in China for the two ore categories, the paper demonstrates the economic drivers behind the Chinese steelmakers’ large investments in the magnetite resources of Western Australia. It does this by estimating the potential value of magnetite concentrate to the steelmaker in the event that the maximum potential is realised by operating the blast furnace with a 100 per cent pellet burden.Under the conditions described, it was found that direct reduction (DR)-grade magnetite concentrate could command a price premium over 62 per cent Fe fines of up to 46 per cent (December 2014 on a cost and freight (CFR) basis). The corresponding premium for blast furnace (BF)-grade magnetite concentrate is 17 per cent, which demonstrates the dependency on grade.The capital expenses for a 14 Mt/a concentrate plant is estimated at US$3.1 B for BF-grade magnetite and US$3.35 B for DR-grade, with operating expenses at US$45 and US$50 respectively. The corresponding free on board price for a break-even net present value is calculated at US$82/t for BF-grade magnetite and US$90/t for DR-grade. The minimum long-term iron ore price (62 per cent Fe) that would be required to underpin such a project is estimated at US$78/t CFR for BF-grade magnetite and US$68/t CFR for DR-grade concentrate.Apart from the financial benefits, it is demonstrated that the use of magnetite concentrate in ironmaking has the potential to reduce CO2 emissions by approximately 400 kg per tonne of hot rolled coil.CITATION:Mouton, A J J and Edwards, K, 2015. Magnetite – a higher-grade blast furnace feed and its potential benefits for the ironmaker, in Proceedings Iron Ore 2015, pp 613–620 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By D. R. Nagaraj, Raymond Farinato

Water constitutes one of the most valuable resources employed in mineral recovery and processing. Identifying potential problems encountered in mineral processing in waters unusable for drinking or agriculture (including seawater and even hypersaline waters), understanding chemical factor interactions, and optimization of flotation reagents will greatly expand our ability to create more sustainable beneficiation technologies. The current paucity of our knowledgebase regarding high salinity effects on flotation clearly signals a need for a significant research effort. We report here results of a study designed to probe effects of pulp chemistry on metallurgical performance in the flotation of Cu and Cu-Mo ores in saline waters. The results clearly demonstrate that pH (more correctly dosage of pH modifier to target a pH set point) has the most significant effect on Mo recovery when using seawater. This is linked to the formation/precipitation of Mg(OH)2 when pH = 10.3 (in seawater). The type of pH modifier used, NaOH or Ca(OH)2, had no impact on Cu or Mo recovery, indicating that Ca2+ ions were not involved in any reduction in Mo recovery in the pH range of 9-11. Our results in tap water spiked with either Ca2+ or Mg2+ ions in the same pH range (controlled by NaOH), confirmed that Ca2+ ions had no effect on Cu or Mo recovery, but that addition of Mg2+ ions had a severe adverse effect on Mo recovery at pH = 9.5, and to a lesser extent on Cu recovery. The onset of Mg(OH)2 precipitation occurred at a higher pH, and the adverse impact of Mg(OH)2 on Cu recovery (and perhaps Mo recovery as well) was less, in sea water than in tap water spiked with Mg2+. These effects are attributed to the mitigating role of the high electrolyte concentration, notably NaCl.

Jan 1, 2014

By H. R. Shell

Of three known compounds in the ternary system K20 - PbO - SiO2, one having the composition K2Pb4Si8021 crystallizes into a structure with asbestiform properties. This compound, whose silicon-oxygen ratio is between that of the layer silicates (for example, mica) and the double-chain amphiboles, crystallizes in the tetragonal system. It malts, apparently congruently, at 779° C. The fiberized product prepared from crystals is fluffy and closely resembles natural asbestos in appearance, but is more brittle and has less strength. However, potassium-lead silicate may be separated into fibers with a uniform diameter of 200-300 A.U., and the fibers show with the electron microscope the s criteria that have been interpreted as indicating a hollow tube structure in chrysotile asbestos. Since very few inorganic crystalline compounds have such a structure, the material has unusual scientific interest. Microcrystalline potassium-lead silicate was rapidly and completely formed when powdered glass of the same composition was heated to 650° - 700° C, but macrocrystals grew only slowly from the viscous massive glass. Maximum growth rate was 0.12mm. per hour at 700° C.

Jan 1, 1957

By G. M. Carr-Harris

"THE SUBJECT of permanent molding has received a great deal of attention in the technical press as illustrated by the many excellent articles in the bibliography which follows. In general, this covers the period 1940-1958 and is merely representative of what is available. Numbers in •brackets refer to items in the bibliography.It may be desirable at the outset to give a few definitions covering those terms directly related to this subject. The following is a definition of permanent-mold casting as given by J. W. Meier in a paper, ""The Non-Ferrous Metals and Alloys"", read before the Ottawa Valley Chapt.er of the American Society for Metals:""Permanent Mold Casting is used where a large number of castings of the same part are required and higher mechanical properties, greater density and closer tolerances are essential. Since metallic mold s are very expensive, the number of castings must be sufficient to, defray, at least partially, the added expense. Molds are usually made from a good quality cast iron, 1but other mold materials, such as the aluminum and copper alloys, graphite, ceramics, etc., are being used in certain cases. Important factors in permanent mold casting are the mold temperature; the proper mold dressing; and, as in all other casting methods, the mold geometry, that is to say, the design of spruces, gates, risers and vents""."

Jan 1, 1960

The use of coal as a fuel causes air, pollution in; a number of different forms, and in nearly all stages of its, handling, preparation, storage, use and-disposal of its residue. First let us consider the handling of coal. As shipped, particularly to large utilities, it is run-of-mine bituminous made up of large chunks as well as pulverized particles. Because it &apos;is in an open car or barge, it is subject to the action o winds and the small particles may be blown around adding to the-particulate load in the atmosphere. Mien un¬loaded from the barge or car, there is again an opportunity for the wind to blow the fine particles around. All of us I am sure have seen a barge at the dock of a utility plant being unloaded by a clamshell bucket. This, after grabbing its load from the barge, lifts it some 60 or 70 feet and, then drops it on a conveyor, which carries the coal to a storage area.

Jan 1, 1964