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The paper describes developments since 1959 in major excavators to meet the demand for higher outputs of overburden and coal under less favourable batter conditions than used hitherto in the coal deposits of the Latrobe Valley. Particular reference is made to investigations of designs of bucket wheel head configurations for the digging of these flat batters on high faces, and examples are given of the wide use of models inthese studies. An explanation is given of how solution of these problems and surface conditions unfavourable for wheeled transport confirmed selection of the long boom rather than the compact type of bucket wheel excavator for the Latrobe Valley applications.The past decade has seen advances in the manufacture in Australia of components for excavators and similar machines. The history of Australian manufacture of components for major brown coal excavators is traced;and reference is made to study and application of Australian and overseas (mainly German) codes and practices in the design and construction of machines made partly here and partly in Germany.A section of the paper deals with advances in electrical engineering for large excavators in Australia and its interdependence with mechanical design and construction.Finally, as an example of the versatility of the bucket wheel excavator, a description is given of a recent application for the mining of mineral sands in northern N.S.W.

Jan 1, 1971

By David T. Hobbs

Large quantities of highly alkaline, radioactive, liquid wastes are stored in underground tanks throughout the Department of Energy complex. These wastes will be pretreated to separate radionuclides and the remaining decontaminated liquid wastes incorporated into solid waste forms for permanent disposal. Significant savings in disposal costs could result by recovering .the sodium as sodium hydroxide for reuse or disposal as nonradioactive waste. Recent testing demonstrated an electrochemical separation process for the recovery of sodium hydroxide from alkaline waste solutions; The separation process uses ion-selective membranes to separate sodium from the bulk of the waste constituents under an applied electrical field. The sodium is recovered as a 10-15 wt % solution of sodium hydroxide. Results of bench-sc3Ie and pilot-scale tests with simulated and radioactive waste solutions are presented.

Jan 1, 1999

By W. Guiye, L. Chongjun, L. Huinan, Z. Yangge, H. Long

The current application of copper-molybdenum (Cu-Mo) separation inhibitors is often associated with large dosage, high toxicity, environmental pollution problems. In order to solve these problems, a light sensitive Cu-Mo separation inhibitor LS（light sensitive inhibitor，abbreviated to LS） was developed. In this paper, inhibitory performance, photodegradation rule, and acting mechanism of LS were studied. The subsequent test results showed that, compared with traditional inhibitors, LS has shown comparative advantages, with lower dosage and good inhibiting effect. A series of flotation tests with LS as inhibitor were conducted on a Cu-Mo concentrate. A locked-cycle test showed that a molybdenum concentrate containing Mo 49.88% and Cu 0.6%, with 93.23% molybdenum recovery and a copper concentrate containing Cu 29.92%, with 99.99% copper recovery can be obtained. The photodegradation performance of the reagent was investigated under 365 nm, 254 nm and sunlight irradiation. The degradation of the reagents could be completely achieved by irradiation of three wavelengths of light. However, with the different wavelength of irradiation light, the degradation rate is different, the time required to reach 50% degradation rate being 3 h (254nm), 4 h (solar light) and 6 h (365nm) respectively. The inhibition mechanism on chalcopyrite was studied. FTIR study showed that LS could be adsorbed on the surface of chalcopyrite by chemical adsorption, which could enhance the hydrophilicity of chalcopyrite. Ultraviolet adsorption tests indicated that the adsorption capacity of LS on chalcopyrite surface was greatly affected by pulp pH value, and the proper pH value was 5-9. Keywords: Copper-molybdenum separation, Inhibitor, Light-sensitive, Photodegradation, Mechanism.

Jan 1, 2020

By B. J. Coetzee, P. W. Sonnendecker

The quality control of a two-stage coal washing process involves several complex components that need to be modelled accurately, to enable autonomous control of the process. The first objective is to develop a method to track the material through the washing process, while ensuring accurate washing prediction models are used. This was achieved through a digital twin model of the Grootegeluk 1 coal processing plant. The model is the amalgamation of manipulating and combining of data-sets from the plant historian, geological wash tables, and mining dispatch servers. This information is then used to control and set the processing medium densities of all 15 modules on the plant, 10 modules in the primary wash and 5 modules in the secondary wash. This controller has been successfully implemented and controlled the plant for 10 days.

Aug 2, 2022

By K. M. Wild, C. D. Martin, F. Amann

"Argillaceous rock formations, in particular clay shales, are notorious for creating challenges in rock engineering. Due to their generally low hydraulic conductivity and their complete saturation in their natural state at depth, the behavior of clay shales is usually characterized by a strong hydro-mechanical coupling.This paper presents typical pore pressure responses monitored in different underground rock laboratories and explores alternative ways for their interpretation. The underpinning processes and their relevance are identified based on analytical and conceptual numerical models. Pore pressure monitoring data from Opalinus clay at the Mont Terri Underground laboratory, the Boom Clay at the Mol facility and the Callovo-Oxfordian clay in the Meuse/Haute–Marne URL show a similar pore-pressure response associated with stress changes accompanying tunnel construction although the tunnels were built in different rock types, at different locations, and under different in-situ conditions.The numerical analyses in this study shows that the pore pressure response around an excavation in low permeable clay shales may have different explanations. Pore pressure drops observed in the tunnel near field can theoretically be explained by both, a pure elastic response in an isotropic or anisotropic rock mass with an anisotropic stress state, or a inelastic response and related dilatancy. However, a comparison between the numerical models and the in-situ measurements revealed that the latter is more likely. This conclusion is justified by the observation that pore pressure drops occur significantly ahead of the tunnel face which is not the case in elastic numerical simulations. Pore pressure measurements in the far field, where failure processes are unlikely to occur, can only partly be explained by a linear poroelastic models. The introduction of an anisotropic material plays a key role in reproducing the responses, conceptually."

Jan 1, 2015

By Lloyd C. J

The uranium markets are at present well covered by available producers. However the predicted increase in demand, recently reinforc- ed by the Arab oil crisis, will by, the early 1980s'outdistance supply. Current trends are towards light water reactors with-fast breeder reactors not expected to make any significant impact to the mid 1980s. The proposed lifting of the US embargo on the use of foreign uranium in US reactors will expand the market available to non US producers. A balancing in supply and demand worldwide will probably occur in the early 1980s. Australia's potential producers at present hold about 20 percent of the worlds U308 resources. Three companies, have contracts to supply nearly 10 900 tonnes of U308 between now and 1986 which represents about 1 percent of the predicted demand to 1986. Australian producers need to establish themselves more firmly in the market place in order that other countries will not replace us. Contracts can be written now which will allow for world market prices to be paid in the future, thus protecting the Australian producer.

Jan 1, 1974

By Qiong Wu, Qinghua Gu, Yichuan Lv, Jin Yuan, Caiwu Lu

"The cut-off grade is one of the important parameters of mining production. Different material cut-off grade is directed to different destinations. Based on reasonable and optimal cut-off grade, long term mining plan and investment decision analysis can be made for mining managers. In view of multiple-metals open-pit, the paper has proposed that multiple-metals cut-off grade optimization model is set using the objective function to maximize net present value (NPV). The method of equivalent coefficient calculation is proposed to convert multi-metals cut-off grade optimization to a single metal cut-off grade optimization. Then the optimization model is applied in a molybdenum and tungsten large open-pit mine in china. The parameters of concentrate price are calculated by PRT in the model and the curve of grade-recovery rate is analyzed and studied according to actual production data. Based on 3D metal deposit model, the distribution of grade-tonnage is analyzed. At final step, an optimal cut-off grade is proposed to guarantee to maximize NPV. The example shows that the model of multiple-metals cut-off grade optimization can provide reasonable analysis for optimal multi-metals cut-off grade and develop optimal production strategies. Introduction Cut-off grade is one of the most important parameters in metal ore mining because of its influence on the overall economic profit of mining production. Along with the development of the mining production, dynamic optimization of cut-off grade is necessary through the analysis of technical economy. It is better to manage the mining production according to the variation of market. The cut-off grade plays an important role in mining production."

Jan 1, 2017

By C. F. Starr

This paper deals with the various types of cable in use in mines, with special attention paid to their construction. There will be a few comments regarding the different insulants, jacketing materials and armouring used, depending on their application. Governing standards and the differences therein will also be discussed.

Jan 1, 1969

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By G. R. Fitterer

In the manufacture of steel by any process the refining period involves the partial elimination of the metalloids carbon, manganese, phosphorus, and silicon, by virtue of their reactions with ferrous oxide. At the end of this refining stage the metal consists chiefly of iron in which small amounts of these materials are dissolved. Unless some deoxidizer is added to the steel at this time, the reaction between carbon and ferrous oxide will continue with such force that it is impossible to form sound steel in the ingot molds. Instead, the product will exhibit a marked porosity due to the formation and trapping of carbon monoxide-the product of the reaction mentioned. However, if deoxidizers are added, steel may be obtained which is dense and free from gas bubbles. At the same time the deoxidation products will remain in the steel as impurities. For example, silicon additions form SiO2 or combinations of SiO2 and FeO. Additions of manganese form deoxidation products consisting of various proportions of MnO and FeO. It is also quite obvious that simultaneous additions of manganese and silicon will form oxide combinations either in the binary system MnO-SiO2 or in the ternary system FeO-MnO-SiO2. Work at the Pittsburgh Experiment Station of the United States Bureau of Mines, in cooperation with the Carnegie Institute of Technology and the Metallurgical Advisory Board, involved the study of such deoxidizing reactions and their products. In this connection considerable information is necessary concerning FeO, MnO, SiO2, and Al2O3, and their various combinations. Some of the most needed data are the melting points of all of these materials. At the outset of this work ordinary methods of melting point determinations were found to be inadequate for various reasons, and the procedure finally selected involved the use of the micropyrometer with occasional corroboration by quenching methods. The reasons for this selection, together with a description of the apparatus, are given in the following pages.

Jan 1, 1932

By Debra A. Griffith

The U.S. Bureau of Mines currently is researching the relationship between the level of back strength and the probability of low-back injury. This report is a review of the literature and statistics on over-exertion injuries. Overexertion continues to be a significant source of injury in metal and nonmetal mining, accounting for approximately 24 pct of all injuries yearly. These injuries, particularly to the lower back, can be very expensive in human and monetary terms. An examination of the accident data on overexertion injuries is necessary to provide a background for research into prevention and/or amelioration of those in-juries. The job categories outlined in the Accident Data Analysis data base most affected are "Mechanic/Electrician" and "Mill/Plant Worker." The age group most affected is "30-39" years, and the experience group most affected is "0-.99" years. The most prevalent type of overexertion injury is "Strain/Sprain," and the trunk is the body part most often involved in an overexertion injury.

Jan 1, 1994

By Feebrey CA, Duncan RA

The Ebor Volcano in northeastern New South Wales is an eroded example of a central-type intraplate volcanic-intrusive complex. It is of Miocene age (19-20 Ma) and has similarities to other central-type volcanoes in eastern Australia which may represent manifestations of sub-lithospheric hotspot activity. Thick lava flows are exposed around the Great Escarpment and are dominated by a tholeiitic basaltic suite, ranging from ol-tholeiite to qz-tholeiite to icelandite with ages of 19.2-19.6 Ma. On its western edge, the tholeiitic lava suite probably overlies remnants of basanite flows belonging to the Eocene (-48 Ma) Doughboy province, but elsewhere, minor alkaline basaltic lavas may be coeval with the tholeiitic suite. Several felsic bodies were emplaced into the volcano at -19.0-19.2 Ma and include subalkaline and peralkaline types. The Crescent Complex is a Miocene-age, strongly differentiated mafic to felsic intrusion in basement rocks and centrally located in pre-erosion reconstructions of the Ebor Volcano. It is interpreted to be a major feeder for the tholeiitic lavas based on age and composition. Evolution of the dominant tholeiitic suite proceeded from a parental ol-tholeiite magma, through qz-tholeiite, icelandite and small volumes of felsic rocks by fractionation of plagioclase, olivine, clinopyroxene and titanomagnetite, accompanied by enrichment of SiO2, F,FeO/MgO, alkalies and HFSE.

Jan 1, 1995

The Anglovaal Group has released details concerning its new processes for recovering platinum group metals, stating that the Group's system, which involves batch processing and precipitation methods for these metals (PGM's), leads to faster recovery times, increased recoveries, and higher purities than the conventional process. Insofar as South Africa's Merensky Reef is concerned, the Anglovaal method of recovering palladium first (as opposed to platinum in the conventional process) enables it to use a much simpler process in the subsequent recovery of platinum and other metals. Because the processes give cleaner separations, the volume of material to be recirculated -and therefore the total volume of material in the recovery circuits- is reduced substantially.

Jan 3, 1976

By C. Peter Hayes

The world continues to change and with it the supply of minerals and metals, the location of centres of production of primary metal and the increasing levels of metals and materials recycling. New technologies are being developed to meet the ongoing search by industry for lower costs, cleaner production and new markets. To keep abreast with these changes, and to utilise fully, the potential benefits of these technical advances, the industry will need a professional workforce having different knowledge, skills and professional attributes than in the previous millennium. What are these skills and attributes? How to best attract and develop the metallurgists of the future, and provide for the ongoing educational and research needs of the industry?

By Schwartz M.

Madagascar's democratic election has led to a return to its position as a preferred trade partner with the USA and a priority market with Canada. Michael Schwartz takes a look at two key mining projects in this recently reinvigorated country

Feb 1, 2015

By M. F. Hawkes

Austenite grain size has long been recognized by metallurgists as an important property of steels because of its influence on toughness, hardenability, ma-chinability and creep strength. Much research has been carried out on wrought steels to develop methods for disclosing austenite grain size, and to, provide knowledge of the grain-size characteristics of steels produced and heat-treated in various ways. Much less work in these fields has been done on steel castings; partly because, owing to the variable and complex microstruc-tures of cast steels, it is frequently very difficult to obtain results that are not questionable. The object of this investigation, therefore, was to establish, for a wide variety of carbon and alloy cast steels, suitable methods for disclosing austenite grain size and some knowledge of the grain-size variations to be expected. The steel foundryman is interested in austenite grain size at two different stages in the manufacture of his products; one is just after the steel is cast, and the other is after any reheating operation carried out above the critical temperature range. In both, it must always be kept in mind that the grain size being sought is actually a previous austenite grain size, and that the austenite no longer exists once the steel has cooled to room temperature. The prob-lem of the investigator is always to use evidence obtained from the structure at room temperature to deduce this previous austenite grain size, which was established the last time the steel existed at a temperature above the critical range. Since most steel castings today are at least annealed or normalized, the measurement of austenite grain size established by heat-treatment will he considered first. More than 50 commercially produced cast steels rcpresenting a wide variety of compositions and melting practices were used in the study. For each steel, grain-size determinations were made after each of three widely varying heat-treating schedules namely, one hour at I550'F, one hour at I700°F, and six hours at 1700 F. The list of steels and results obtained on them will be found in the appendix. (See page 530.) A discussion of the knowledge gained on the applicability of various test methods and on grain-size characteristics of cast steels in general follows. MEASUREMENT OF AUSTENITE GRAIN SIZE ESTABLISHED BY HEAT TREATMENT Methods Suitable foR Determining Austenite Grain Size after Heat-treatment at Ordinary Temperatures and Times It was desired, as one of the results of this investigation, to be able to recommend to steel foundries a method, or methods, of disclosing grain size best suited to accurate

Jan 1, 1948

By M. F. Hawkes

Austenite grain size has long been recognized by metallurgists as an important property of steels because of its influence on toughness, hardenability, ma-chinability and creep strength. Much research has been carried out on wrought steels to develop methods for disclosing austenite grain size, and to, provide knowledge of the grain-size characteristics of steels produced and heat-treated in various ways. Much less work in these fields has been done on steel castings; partly because, owing to the variable and complex microstruc-tures of cast steels, it is frequently very difficult to obtain results that are not questionable. The object of this investigation, therefore, was to establish, for a wide variety of carbon and alloy cast steels, suitable methods for disclosing austenite grain size and some knowledge of the grain-size variations to be expected. The steel foundryman is interested in austenite grain size at two different stages in the manufacture of his products; one is just after the steel is cast, and the other is after any reheating operation carried out above the critical temperature range. In both, it must always be kept in mind that the grain size being sought is actually a previous austenite grain size, and that the austenite no longer exists once the steel has cooled to room temperature. The prob-lem of the investigator is always to use evidence obtained from the structure at room temperature to deduce this previous austenite grain size, which was established the last time the steel existed at a temperature above the critical range. Since most steel castings today are at least annealed or normalized, the measurement of austenite grain size established by heat-treatment will he considered first. More than 50 commercially produced cast steels rcpresenting a wide variety of compositions and melting practices were used in the study. For each steel, grain-size determinations were made after each of three widely varying heat-treating schedules namely, one hour at I550'F, one hour at I700°F, and six hours at 1700 F. The list of steels and results obtained on them will be found in the appendix. (See page 530.) A discussion of the knowledge gained on the applicability of various test methods and on grain-size characteristics of cast steels in general follows. MEASUREMENT OF AUSTENITE GRAIN SIZE ESTABLISHED BY HEAT TREATMENT Methods Suitable foR Determining Austenite Grain Size after Heat-treatment at Ordinary Temperatures and Times It was desired, as one of the results of this investigation, to be able to recommend to steel foundries a method, or methods, of disclosing grain size best suited to accurate

Jan 1, 1948

By Joseph Githiria, Khadija Omar Said

Mineable material is defined using cut-off grade either as geological or economic cut-off grade. Both geological and economic cut-off grade affects the output generated in an open-pit mining operation. It distinguishes the amount of ore sent to the mill for processing and waste to the dump. This consequently affects the overall profits generated from the operation hence the need for cut-off grade optimization. There are several mining parameters that are considered in a typical cut-off grade model. They include economic, geological, and operational parameters. They have a significant effect to influence the cut-off grade selected in mining operations at any given period. Some of the parameters are stochastic in nature by having a random probability distribution that may not be predicted precisely. When selecting cut-off grades in a mine operation, the mining engineers must consider the dynamic nature of the operational parameters in order to maximize the net present value of the project. Modifying Lane’s cut-off grade model which was developed in 1964 to incorporate the stochastic parameters in the approach helps improve the net present value as shown in the paper. The modified Lane’s approach is developed into a stochastic computer-aided application code-named NPVMining. Using NPVMining, selected stochastic parameters are considered in this exercise to show the effect on the output (net present value). The selected parameters (price and grade-tonnage) are varied by ± 10%. NPVMining has a graphical user interface that makes it easy to use and displays results in a user-friendly way. It gives the user the choice to manipulate the data depending on the study being undertaken or any other factor affecting the specific mine. This paper analyses the effect of each of the selected mining parameters on cut-off grade using NPVMining to show the significance of monitoring their variance.

Jun 25, 2023

By K T. Broekman, R L. Koenig

"The Braemar Iron Formation is atypical ore when compared to the current magnetite ores being processed. In attempting to process and economically recover the vast quantities of iron ore stored within the Braemar Iron Formation, æshifting the paradigmÆ is required. The formation has a low Davis tube recovery (DTR) grade of 15 - 20 per cent, which is much lower than magnetite ores processed in Australia. Despite this, by thoroughly testing and understanding the ore characteristics, it is found that the Braemar ores have significant advantages to processing than the harder banded iron formation (BIF) and taconite resources.The Hawsons magnetite iron ore resource has been known from the early 1960s when CRA explored the area. The grade was low and the Pilbara region discovery lead to the development of high-grade direct shipping hematite ores. Carpentaria Exploration (CAP) rediscovered the magnetite whilst undertaking multi-commodity exploration in the Broken Hill district during 2009. Shifting the paradigm away from grade the advantages of processing this ore are achieved by having an extremely low waste to ore ratio, lower Bond work index, lower abrasion levels and high-grade magnetite concentrates with little impurities other than silica. While developing the Hawsons Iron Project (HIP) it became more apparent that a positive business case is achievable when the following factors are exploited: very large resource - the resource is contained within one pit the rock fractures easily along grain boundaries - ideal for cheap impact crushing of the ore the ore is extremely soft, with a Bond work index of 6.3 - 8.0 kWh/t all major infrastructure required is readily available - rail, power, access and port the mine is in close proximity to Broken Hill - rich mining history and skill set available the resource contains many billions of tonnes of magnetite mineralisation.Shifting the paradigm by selecting equipment suitable for processing soft ores and not hard BIF or taconite ores and taking locality and available infrastructure into account may change the way people approach new low-grade resources in future.CITATION:Koenig, R L and Broekman, K T, 2013. Understanding ore characteristics and equipment selection, in Proceedings Iron Ore 2013, pp 403-410 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By J. S. Stewart

THE Mackenzie River Valley proper extends from Great Slave lake to the Arctic ocean (see map, Figure 1). From Fort Providence, near Great Slave lake, to Aklavik, near the Arctic coast, the distance by river is 1,000 miles. This will give some idea of the extent of the region. Throughout the length of the river valley, the Precambrian complex rocks are overlain by unaltered sedimentary rocks several thousand feet in thickness. These sediments are dominantly marine and Palaeozoic in age. In places, the Palaeozoic strata are overlain unconformable by Cretaceous an Tertiary sediments. The strata have been folded and, in general, the inclination of the beds to the horizontal is comparatively gentle. Here, then, we have the essentials for potential oil fields covering an area over 1,000 miles in length. This is probably the largest comparatively unexplored potential petroleum region in North America, and surface evidences of oil in the form of seepages occur in several places. Many of these seeps were known to the early explorers, and the first Geological Survey report on the Mackenzie River region, containing the results of field work carried out by R. G. McConnell in 1887-88, noted the petroliferous character of the Devonian strata and the indications of petroleum(l). This region is, however, handicapped by distance from markets and sources of supply of materials; by lack of modern transport facilities; by short season for river transport, and mountainous country separating the valley from the Pacific seaboard; and by the long winter season with weather that makes outdoor work difficult. These factors have tended to discourage the enthusiasm of would-be promoters, and so development in this region has been slow In 1920, a test well drilled about fifty miles northwest of Fort Norman discovered oil in commercial quantity, and three additional wells proved a small area to be productive.

Jan 1, 1944