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By J. A. Kinnaird, B. J. Youlton, K. L. Youlton

Methods for treating and processing refractory gold ores are well established. However, what is less well understood is how the formation of the gold-bearing deposits affects gold processing and extraction. In order to evaluate the effect of ore genesis on gold extraction a number of South African gold deposits were studied. These included complex Pilgrim’s Rest samples as well as refractory Fairview, Barbrook, and Consolidated Murchison samples. We found the refractory nature of gold ores is controlled by a limited number of well-understood mineralogical factors. Solid solution gold is linked to low temperature and pressure conditions in fine-grained sedimentary lithologies, while reactive pyrrhotite can form from hydrothermal fluids associated with mafic magmatic rocks. These formational controls can be used to identify and avoid complex deposits at a desktop study phase, or address and reduce complications further along the pipeline using early mineralogical studies.

Jun 1, 2021

By Q Qu

Reliable prediction of longwall gas emission sources and rate plays a critical role in mine ventilation and methane drainage capacity planning. Over the years, Australian longwall mines have been using the historic Winter method and the Flugge method in modelling specific gas emissions (SGE). The predicted results often experience high discrepancies from the operational reality. To improve gas emission prediction, post-mining gas contents were measured in several mines in Qld and NSW by safely drilling core holes into the longwall goaf. The results revealed many new insights into gas emission characteristics from different coal seams and the drawbacks of the European methods in their use in high-production gassy Australian longwall mines. Based on measurement data, a new, time-dependent gas emission prediction model has been developed. Considering several factors such as caving, desorption and production rate, the new model can predict more accurate and meaningful gas emissions to meet today’s needs in mine gas emission management. A case study is provided to demonstrate the application of the new SGE model.

Oct 12, 2022

By John Dixon

This paper is one of a series on milling methods and costs being published by the Bureau of Mines. Acknowledgment is made to J. B. Tyrrell, managing director, and Wm. Sixt, manager of the Kirkland Lake Gold Mines, for permission to publish this article. The Kirkland Lake Geld Mining Co.'s mill is located on Government Road at the west end of the productive part of the Kirkland Lake mining area, 1 mile west of the village of Kirkland Lake. The crushing plant is connected to the shaft house of No. 2 shaft, which is now the only operating shaft.

Jan 1, 1931

By K. Galos

The paper presents increasing importance of mineral secondary and waste raw materials in the minerals management in Poland. Definition of mineral secondary and waste raw materials is proposed, according to current Polish law. On this basis, sources of various types of mineral waste raw materials are analysed. The special attention is paid to the wastes from mining and processing, wastes from power plants, and wastes from steelworks and other smelters. Other types of waste and secondary materials, such as metallic containers, glass containers, batteries, metallic wastes and scraps, are also taken into account. Analysis of sources of such materials is shown together with the main directions of their economic use. Available sources of information on manufacture and use of the mentioned secondary and waste raw materials are also analysed. Finally, for a wide range of waste materials, their current and expected significance as substitutes for some industrial and construction minerals in Poland is given.

Jan 1, 2011

By G. W. Birge

The Bureau of Mines investigated the effect of temperature on the mechanical strength of cokes of the type normally used in blast furnace operations. Eight samples of industrially produced cokes were subjected to ASTM tumbler tests at temperatures as high as 1,100° C (2,012° F); these temperatures had no significant effect on tumbler results for cokes with stability indexes of 40.6 to 59.9. Two foundry cokes which were tested at only one elevated temperature (900° C) decreased slightly in tumbler stability. Iron are pellets made from a variety of ores and by various industrial methods were not significantly affected by temperature when tested in an oxidizing atmosphere at 1,000° C (1,832° F) by the tentative standard ASTM method.

Jan 1, 1966

By ALEC CROWELL

Mississippi has had oil production for only the past six years and natural gas production of minor magnitude since' 1926. The search for oil and gas commenced in 1903 and 1496 wells had been drilled in search of oil and gas up to Jan. 1, 1946. As the year 1945 ended, 659 wells were producing oil and gas from 23 separate reservoirs. The production for the year was 8,353,719,000 standard cubic feet of natural gas measured on a pressure base of 15.025 lb. per sq. in. abs., 15.316,009 bbl. of oil¬field water and 19,093,766 bbl. of crude oil and condensate. Production for the year 1944 was 2,636,067,000 standard cubic feet of gas, 14,979,793 bbl. of salt water and 16,420,346 bbl. of crude oil and condensate.

Jan 1, 1946

By James H. Harmon

As the trend to deeper mines, producing from marginal ore bodies, continues, mine hoists and their associated equipment will become more sophisticated, complex, large and expensive. Over the past two decades, mine hoisting equipment and systems have moved from steam engines to static rectification of ac to dc, and electronic controls are the standard. It is the intent of this section to present what is currently available in the field of mine hoisting equipment and systems. Because the present engineer has been exposed longer and more intensively to such things as computers, electronic devices, and machine design, no attempt has been made to make this a layman's article. Contributions from the electrical design and application engineer, gearing and hearing design engineers and other specialists have been incorporated. Some material will be devoted to electrical drive systems, rectifiers and gearing design among others. These items are inherent in the design of a mine hoisting system and the subsequent selection of the correct, most reliable and most economic system. The mine hoist can be a bottleneck between the underground mine and the surface mill. Correct selection of the right type of hoist is imperative. In this vital link between mine and mill, crude estimates of hoist capacity are not good enough, and the mining engineer must design and select the right hoisting system to meet the design specifications. 15.1-MINE HOIST TYPES There are two basic types of mine hoists available anywhere in the world today: the drum hoist on which the hoist rope is actually stored during the hoisting cycle, and the friction (Koepe), which merely passes the rope over the wheel during the hoisting process. Drum and friction hoists are "generic" terms which describe the two basic categories. Within each category are variations, as below. 15.1.1-DRUM HOISTS Drum hoists, as noted, actually store the hoist rope on the drum much the same as line on a fishing reel. To accomplish this task, the drums are so designed to store, in one or more layers, the footage of wire rope equal to the total maximum hoisting distance plus sufficient rope for cutting and inspection at regular intervals and for holding to the drum (see Fig. 15-1). Usual practice in hoist drum design is to allow three turns of hoist rope for holding on the drum and three turns for inspection cuttings. 1. Single-Drum Hoists-Fig. 15-2 shows a typical single-drum hoist as manufactured by most U.S. heavy-mining-equipment companies. With the exception of some very minor features, this design configuration is standard throughout the U.S.A. Fig. 15-3 is a plan view of a typical single-drum mine hoist. This particular hoist has a single-motor drive and a double-reduction set of gearing.

Jan 1, 1973

By M. T. Ityokumbul

The effect of reaction conditions on the desulphurization of oil sand coke residues has been studied. The variables investigated were temperature, reaction time, heat transfer resistance, and mode of caustic soda addition. The results obtained show that oil sand coke desulphurization increases with temperature, reaction time, and heat transfer rate. In an oxidative environment, coke combustion during molten caustic leaching (MCL) commences at temperatures above 500°C. The mode of caustic addition has no effect on coke desulphurization.

Jan 1, 1995

By Xiang-ning Meng, Miao-yong Zhu

"A three-dimensional finite-element heat-transfer model is conducted to predict temperature of hot copper plate in a slab continuous casting mold and the effect of casting speed on temperature difference between copper plate and solidifying shell is simulated in combination with process data. The results show that centre temperature of hot copper surface at casting speed 1.8 m·min-1 and 2.0 m·min-1 are higher than that of 1.6 m·min-1 casting speed 4.7-5.2 °C and 11.2-12.2 °C respectively and temperature is not increased linearly with casting speed. Temperature difference in meniscus between mold and shell is influenced obviously by casting speed and increased 4.0- 6.0 °C with increment of casting speed 0.2 m·min-1• Fluctuation of temperature difference in meniscus is a main reason to deteriorate casting quality as increasing casting speed.IntroductionIn conventional continuous casting of steel, a large amount of sensible and latent heat of molten steel dissipates in primary cooling zone and mold becomes a critical component of caster to govern steel quality, meanwhile, thermal load on mold is increased constantly and environment is also more abominable since high productivity and quality are required and high-effective technologies are applied. So, an in-depth understanding of thermal behavior of mold at high casting speed is essential to design cooling structure and maintain casting stability. Many studies have been carried out to shed light on thermal behavior in mold. Chow et al. [l] applied a mathematical model to heat transfer in billet mold at a high casting speed to give a new taper in order to minimize mold-strand interaction. Thomas et al. [2] researched relation between mold geometry and temperature distribution based on a finite-element heat-transfer model. Lu et al. [3] indicated that slab mold temperature are mainly affected by thickness of copper plate and nickel layer by a heat transfer model. Samarasekera et al. [4, 5] researched temperature of copper plates for both billet and slab molds and effect of a large number of factors ranging from water quality to casting speed. Park and Thomas et al. [6, 7] developed a finite-element thermal-stress model to determine temperature and thermal distortion and stress in both thin and slab molds and O'Connor et al. [8] applied an elastic-plastic-creep finite-element model in a funnel shaped mold to achieve same goals. Cicutti et al. [9] evaluated heat transfer and temperature fluctuation in a slab mold and proposed an expression to predict global heat flux as a function of process parameters and an index to quantify thermal instability. All mentioned above shown that thermal behavior is not only important to casting stability, it is also premise to further understand mechanical behavior in mold."

Jan 1, 2011

By Zach Agioutantis, Christopher Mark

"Thirty years ago, the Analysis of Longwall Pillar Stability (ALPS) inaugurated a new era in coal pillar design. ALPS was the first empirical pillar design technique to consider the abutment loads that arise from full extraction, and the first to be calibrated using an extensive database of mining case histories. ALPS was followed by the Analysis of Retreat Mining Stability (ARMPS) and the Analysis of Multiple Seam Stability (AMSS). These methods incorporated other innovations, including the Coal Mine Roof Rating (CMRR), the Mark-Bieniawski pillar strength formula, and the pressure arch loading model. They also built upon ever larger case history databases and employed more sophisticated statistical methods.Today, these empirical methods are used in nearly every underground coal mine in the US. However, the piecemeal manner in which these methods have evolved resulted in some weaknesses. For example, in certain situations, it may not be obvious which program is the best to use. Other times the results from the different programs are not entirely consistent with each other. The programs have also not been updated for several years, and some changes were necessary to keep pace with new developments in mining practice.The Analysis of Coal Pillar Stability (ACPS) now integrates all three of the older software packages into a single pillar design framework. ACPS also incorporates the latest research findings in the field of pillar design, including an expanded multiple seam case history data base and a new method to evaluate room and pillar panels containing multiple rows of pillars left in place during pillar recovery. ACPS also includes updated guidance and warnings for users and features upgraded help files and graphics.INTRODUCTIONPillar design is one of the fundamental elements of mining engineering. Pillars are necessary to control the great weight of the overburden during all phases of underground mining. Without stable pillars, ground control is impossible."

Jan 1, 2018

By G McKay, M Erskine, S Macklin

The City of Sydney is currently investing in a number of infrastructure projects that require tunnel excavations within the Triassic Hawkesbury Sandstone. It is generally accepted that this formation has high residual stresses of ‘tectonic’ origin, so much so that these stresses have been implicated in a number of well-known failures and problems for tunnelling. These include failure of ‘roof beams’ comprising discrete beds in the crown of tunnel excavations; stress-induced spalling and ‘slabbing’ of tunnel walls; shear displacement between beds causing the failure of rock bolts; strain in adjacent infrastructure and, the necessity for re-grouting of high conductivity fractures due to stress relief dilation after excavation. Whilst there is an extensive published database of in situ stress measurements comprising ‘hydrofrac’, ‘over-coring’ and ‘slotter’ stress measurements, these data indicate a considerable spread of results. The traditional approach to interpreting this data has been to attempt to fit linear correlations to stress versus depth data, based on personal experience and ‘back-analysis’ of monitoring data during construction. However, there are a number of such correlations in the literature and there is divergence of opinion regarding the assessment of ‘background’ in situ stress and appropriate upper and lower bound values for design. This paper provides a brief review of the published data; suggestions on an alternative ‘risk-based approach’ to assigning in situ stresses for design; and, proposals on how in situ stress tests may be conducted in future to improve the quality of the database available to designers.CITATION:Macklin, S, McKay, G and Erskine, M, 2014. A review of the in situ stress database for tunnel design in the Hawkesbury Sandstone, Sydney, New South Wales, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 171–178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K Timtner

As shown in former publications there are problems in load sharing of backstops in multiple drives of conveyors. Therefore, detailed calculation methods and design recommendations are required. In this paper various designs of load sharing methods are described and a dynamic torque calculation method will be presented. With this method the loadsharing properties for low and high speed backstops are calculated and compared. These properties depend on the spring characteristic of the drive train between backstop and load. Furthermore, the properties depend on the method of torquearm support and shock absorber configuration. Remarkable differences for external and internal backstops are shown

Jan 1, 1998

By M. E. Rossi

Reconciliation of production information is critical to evaluating the effectiveness of the predictive models, and to allow for optimization of mining operations. Whether mining open pit or underground, mine-to-mill reconciliations can be one of management's better tools to perform proper accounting, and a very useful evaluation and optimization tool. This paper proposes a set of criteria and objectives for a typical reconciliation program; also presents a stepwise, logic approach to performing reconciliations, and discusses the benefits and costs associated with the up-keeping of the information. It also highlights some of the potential pitfalls involved, and methods used to avoid collecting misleading information. These issues are illustrated with an example of a model-to-mine-to-mill reconciliation program being implemented at an operating mine; the program involves multiple predictive models (Long-term and Short-term block models), different open pit and underground mines, stockpiling, and at least 23 different mill streams. This paper presents the initial results of the program implemented at Minera Michilla S.A.

Jan 1, 1999

By David Hill

"End of panel longwall face recovery is almost certainly the most involved recurring geotechnical problem faced by operators, with major loss potential should problems occur. The paper presents Australian experiences and updates the outcomes of an industry sponsored research project on the geotechnical issues associated with conventional longwall recoveries.A number of critical features of the geotechnical environment, support design and mining geometry have a pronounced impact on ground control during face recovery. A model of roof behaviour at the take-off point has been developed and validated. Key geotechnical issues include low roof competency, an adverse weighting environment, geological structure, horizontal stress concentrations at the gate ends and the capacity and. integrity of the shields. All of these are identifiable either at the support design stage or, at worst, prior to the start of powered support removal, which is the critical stage of the recovery process.Key aspects of the geometry and process are the ability to maintain powered support resistance during bolt-up and recovery, the direction of shield removal, the impact of chutes and the speed of the shield removal process.The author presents case studies that illustrate these issues and the associated ground behavior.INTRODUCTIONEnd of panel face recovery is almost certainly the most involved recurring geotechnical problem faced by operators, with major loss potential should problems occur. However, unlike most geotechnical aspects of coal mining, very little research has historically been undertaken on the issue of conventional longwall recoveries. This is in marked contrast to the design of pre-driven recovery rooms, an issue which has attracted considerable research interest (Thomas, 2008). In 2006, Strata Engineering completed an Australian industry (ACARP) sponsored research project aimed at defining and minimising the geotechnical threats during longwall face recovery (Strata Engineering, 2006). The research project had the overall objective of developing guidelines for the specification of ground control strategies, so as to minimise the likely geotechnical threats relating to the safety, operational costs and production delays associated with the recovery of a longwall face."

Jan 1, 2010

By Kush Patel

This paper presents methods currently available for the evaluation of bulk explosives and discusses the results of the evaluation of bulk explosives using each of the methods. Through the preliminary experimental analysis, wet chemistry and the Bulk Explosive Analyser were found as methods most suitable for the evaluation of bulk explosives. This paper also presents data obtained from the experimental comparison of the wet chemistry method and the Bulk Explosive Analyser.

Feb 1, 2020

By Syamujulu. M

Subsequent to the unbundling of the Zambia Consolidated Copper Mines (ZCCM) and the privatization of its constituent parts, the Konkola Copper Mines (KCM) represents a third of the original conglomerate. Now run by private hands as a sub group of Vedanta Resources Plc of India, KCM is strategizing on how best to deal with the operational issues of the organisation to resolve some of the difficult, logistical, environmental, mineralogical and metallurgical problems being encountered to tum them into opportunities as the company turns around. This paper reviews the options being put in place to provide appropriate solutions and strategies including the treatment of the highly siliceous low energy copper belt concentrates in its mining operations in Zambia.

Jan 1, 2007

By A Karrech, G M. Hassan, A Varghese, E Lessing, S Martins

Pumps play a critical role in mining operations, and their energy consumption and environmental impact are significant. This paper addresses the need for a holistic approach to sustainable pump deployment by expanding on previous work presented at IMPC Asia Pacific 2022 and World Mining Congress 2023. The research takes a significant step forward by outlining a structured approach to estimate and demonstrate sustainability tailored for operational slurry pumps. It details the calculation methodologies used to quantify the carbon dioxide emissions from electricity, wear materials and transport, as well as sealing water usage. To enhance practicality and usability, a simplified visual representation—called sustainability metrics—has been developed to monitor overall efficiency. The sustainability metrics consist of the availability, pump efficiency, and water utilisation efficiency. The proposed methodology is integrated with Pumps Condition Monitoring Service to maximise benefits. Three case studies, from iron ore, copper, and nickel operations globally, were employed to evaluate the proposed methodology. The findings demonstrate the critical role of sustainability calculations in understanding pumps operation. These calculations improve awareness of the pump’s role in the sustainability journey and enable effective monitoring. The studies highlight that continuous monitoring paired with effective prescriptive maintenance strategy can significantly reduce power and water consumption while maximising pump availability. The case studies also reveal significant shortcomings in current operational practices and non-optimal maintenance regimes, emphasising the need for practical recommendations to maximise savings and optimise pump performance. In the context of increasing climate change awareness and the imperative for global decarbonisation, this research highlights the necessity of critically assessing methods and operations to drive sustainability in the mining industry. By adopting a holistic approach to sustainable pump deployment, mining operations can effectively reduce their environmental impact while enhancing operational efficiency and economic viability. The proposed methodology and case studies provide valuable insights and practical recommendations for mining companies seeking to achieve sustainable practices and contribute to a decarbonised future.

Sep 1, 2024

By E. G. Bazeley

The paper reviews the scope, timing and financial impact of this significant project, which involves the supply and transportation of nearly 4 million tons per year of bituminous coal and lignite from sources in British Columbia. Alberta and Saskatchewan to Ontario Hydro's generating stations. The critical factors involved in the selection and utilization of these coals are discussed in relation to the three types of coal to be utilized initially. The paper then deals with each of the significant project elements to be undertaken by the various companies involved in the mining and movement of the coal, beginning with production at the mine through rail shipment to Thunder Bay, train-to-ship terminalling, shipment by lake vessel from there to the generating station, and finally blending the bituminous coal with United States coal prior to combustion. The review discusses the key features of the facilities involved in each case and the status and timing of the project elements , which are phased for the start of coal shipment by mid-1978. The paper concludes with some observations on the capability of the project to handle increased tonnage s and the challenges facing the movement in terms of quality , quantity and cost.

Jan 1, 1978

By Yoichi Takeda

The CaO-FeOx-Cu20 slag has been practically applied to continuous converting of copper, and also has potential for refining of copper. Liquidus lines of the slag system and phase stability diagram for the liquid slag and the existing solid compounds under copper saturation are presented. Liquidus composition was determined by chemical analysis of slag sample saturated primary solid. The temperatures of invariant equilibria were investigated by thermal analyses. Oxygen potentials on the liquidus lines, the univariant and invariant equilibria were estimated from the relation slag composition and oxygen potential that relation was confirmed in separate experiments.

Jan 1, 2003

By Michael Zurowski

This paper traces the history of International Mogul's assessment program on the Lake Ainslie barite-fluorite deposits of Cape Breton Island. The geology of the area is outlined, and the main vein systems described. The geophysical and geochemical exploration techniques employed are explained, the metallurgy of the ore is covered, and the market prices and economics of operation are described.

Jan 1, 1972