Search Documents

By J. C. Hawkins

Determining moisture content and rate of flow of a solid product make measurement and control of dryers unusually difficult. This paper de-scribes a method of accomplishing this with readily made air-temperature measurements. The system can cope with changes in feed moisture and feed rate. It does not measure solids temperature. The system's application to several typical rotary dryers is described, and control schemes using feedforward techniques are explained.

Jan 1, 1971

By Terry J. Kreidler

In recent years, west-central Arizona and adjacent California have become the focus of geologic and exploration attention because of its excellent exposure of detachment-fault terrane. Detachment faults, normal faults with nearly horizontal fault planes, are the result of regional extension. Rocks on the lower plate consist of mylonitized intrusive, metasedimentary and crystalline rocks highly altered to chlorite; upper plate rocks comprise sedimentary, volcanic, metasedimentary, and metavolcanic rocks. The movement of the detachment fault causes the rocks on the upper plate to be severely fractured and brecciated thus making them Ideal conduits for mineralizing fluids. Mineralization favored the more reactive sedimentary and volcanic rocks of the upper plate. Three gold deposits, located in upper plate rocks, are currently being mined along the Colorado River corridor: the Picacho Mine near Yuma, Arizona, 70 mi south of the study area; the American Girl Mine In southeastern California, 60 mi southwest; and the Copperstone Mine near the southern end of this study area. Samples from the above three mines were used to create a geochemical model of detachment-related gold deposits. Antimony, arsenic, barium, copper, mercury, molybdenum, manganese, tungsten, and zinc all occur In the mine samples in concentrations at least three times greater than found elsewhere in similar rock types. Samples taken by the Bureau from the wilderness study areas contain similar anomalous concentrations of the same elements as well as elevated concentrations of several other elements Including: lead, fluorine, cerium, uranium, and samarium.

Jan 1, 1992

By S. J. van Wyk, A. S. H. Haagner

Land rehabilitation transcends the mere establishment of vegetation across disturbed landscapes; it should be conceptualised as a specialised ecological reconstruction process. This process necessitates a long-term perspective on the success of land repurposing. It requires a continuum of inputs specified and managed by a dedicated and qualified custodian to ensure the sustained economic viability and ecological sustainability of the land. Based on the authors’ combined experience and field observations over more than five decades, they advocate for an urgent shift away from traditional land rehabilitation practices toward a paradigm centred on land capability reconstruction and active stewardship. The prevailing rehabilitation culture has overly simplified the process to a mere revegetation exercise, which is fundamentally incompatible with the comprehensive requirements for sustainable land capability. While the regulatory framework provides valuable guidance for obtaining a mine’s social license to operate, a paradigm reset is essential. Mining companies must prioritise rehabilitation quality, set achievable sustainability goals, and establish clear pathways and milestones to meet relinquishment criteria. Currently, the status quo view—a model reliant on outsourced contracting and agricultural approaches—is that mine rehabilitation is a one-time intervention rather than a complex, systemic, and long-term process. This perspective presents significant challenges, as the success of ecological interventions can only be accurately assessed over extended timeframes, often spanning decades. Shortsighted rehabilitation specifications, coupled with practitioners operating within agricultural decision frameworks, frequently overlook the necessity for integrated rehabilitation expertise and the scientific foundation essential for designing and implementing effective ecological outcomes. A lack of long-term monitoring information impedes the required adaptive management of rehabilitated systems and, therefore, delays the transition towards final land use. This short approach costs the mining industry millions annually, often without recognising the inadequacies in long-term liability mitigation and the substandard ecological success achieved. The disconnect between procurement processes, the qualifications of service providers, and the unclear pathways to relinquishment can impede successful rehabilitation outcomes, frequently undermining progress toward sustainability milestones. Unless there is a fundamental reset of the land rehabilitation culture, pursuing sustainability will remain an elusive and perhaps impossible objective. Consequently, mining companies may hesitate to fully commit to sustainable land rehabilitation practices, as the prospects for relinquishment and final closure remain uncertain at best.

Apr 25, 2025

By Tim Deans

This paper will address methods to manage hydraulic hose and coupling inventory so that parts will be available to build assemblies for the vast majority of equipment with as little inventory as possible. Topics also to be covered will include some basic hose assembly tagging techniques that will help keep equipment running by tracking problem hoses and building ?band aid? kits, having problem hoses premade in stock, and inventory usage tracking (one of the biggest problems for any inventory manager is knowing which couplings have been used so they can re-order). Cradle to grave tracking of hydraulic and industrial hoses insures reliable service of vehicles and ethical disposal of old hoses and couplings. With accountability for disposal of hose products that may contain chlorine (neoprene tube material in some hydraulic hoses) and carbon black that will be scrutinized more closely in the future, a proactive approach should be adopted in order to minimize maintenance facility problems.

Aug 1, 2013

By Marcelo Rebellato, Leonardo Silvestre, Zhang Yongqing, Felipe Bastos, Zhang Weiqiang

This work reviews the new version of GB1499.2-2018 Chinese national standard and specification, which governs the production of high-strength reinforcing hot rolled ribbed bars in China. In addition, it discusses the main concerns from Chinese rebar makers that might affect production and application of Nb-bearing rebars, like reheating temperature required to dissolve given niobium additions, the promotion of bainite microstructure and continuous yielding, as well as Nb strengthening effects. Through extensive investigation involving both thermomechanical laboratory simulations and industrial trial, the existing state and effects of Niobium along the reheating, rolling and cooling are illustrated. At the end, optimum processing conditions have been established to produce high strength rebars for the specified requirements. The adoption of new process conditions reflected in an amount of about 20.0 million tons of Nb-bearing rebar being produced in China in 2018 with required tensile properties and microstructure, and helped rebar makers to reduce production costs considerably. Based on production data, Niobium demonstrated positive strengthening effect for high strength rebars, in particular for small diameter rebars with earthquake resistant performance. What is more, the results of the research enrich the knowledge of the application of Niobium in steels when TMCP rolling is not used.

Oct 1, 2019

By J J. L du Plessis

Escalating energy and electricity costs have become one of the biggest expenditure drivers in mining operations. During the last eight years, energy costs have trebled when expressed as a percentage of total running cost in South African mines. Power consumption on mines is controlled by three main strategies, namely load clipping where energy use is reduced for parts of the day, load shifting where energy use is shifted to other parts of the day, and energy efficiency where energy use is reduced permanently.To reduce the operating costs of ventilating and cooling underground mines continuously, system optimisation studies must be completed. A part of this paper describes methods that can be used to reduce energy usage by optimising cooling and ventilation systems during planning and in existing operations using network simulation models that accurately reflect the current and planned ventilation conditions. These models are used to examine various options for improving the overall ventilation and cooling efficiency. Furthermore, an overview of refrigeration and cooling practices, and ventilation strategies is presented.Ventilation-on-demand and cooling-on-demand strategies have the potential to reduce both the capital and operating costs associated with mine ventilation and cooling systems. In addition, it has been proven that modern strategies and energy-efficient tactics are technically feasible.It is also important that the correct equipment selection is made. This must be based on the best technology with the highest energy efficiency. Where equipment replacement is being considered, energy efficiency must be one of the key decision drivers.In this paper a number of studies were presented and from the experience and the data presented it is clear that a large financial benefit is possible through optimising ventilation and cooling during the planning of mines or within an existing operating mine.CITATION:du Plessis, J J L, 2015. Strategy and tactics implemented to achieve energy-efficient ventilation and cooling of mines, in Proceedings The Australian Mine Ventilation Conference, pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By R. F. Favreau, L. C. Lang

"In modern blasting technology blasts are designed and analysed on an energy-mass-time relationship. The energy of the explosive is derived by computer analysis and the work potential of the available energy is expressed in numerical values. The mass involved in the blast is determined by the geometry of the blast and by the rock density. Time is also a relevant parameter, because time is required to complete the three basic stages of the breakage process.For successful application of the blasting parameters the basic mechanism of the breakage process must be understood.The physical-mechanical properties of the rock, local structural geology and the thermodynamic properties of the explosives can be brought together to create a computer model of a blast with which it is possible to predict separately the results of each parameter and to express the predicted degree of change in any parameter by actual numbers.A long-range project has started to create a ""bank"" of rock properties for as many Canadian and foreign mines as possible. A computer model has been successfully applied to predicting the effect of varying the ratio of spacing to burden at constant rock volume and significantly improved results are achieved, as the S/B ratio is increased up to about 2 to 2.5.High-speed photography has been applied to determine the time that has elapsed between zero time and the beginning of movement of the mass. The results assist in determining minimum and optimum delay time required for multiple-row blasting.The approach as described in the paper is now well proven and is clearly superior to previous methods based on powder factors and human assessment."

Jan 1, 1972

By D. A. Elkins

This report is the second of a series of three that will evaluate, in order, the metallothermic, carbothermic, and electrolytic methods of magnesium production. The historical development of the carbothermic process is outlined. Production costs varying from 38.9 to 21.8 cents per pound of magnesium are estimated for different versions of the process. Additional suggested process modifications are listed. The technical and economic potential of the different versions are compared. Areas deemed most promising for future research on the process are delineated.

Jan 1, 1967

Olympic Dam Operation is located in the Stuart Shelf Geological Province approximately 520 km north-north-west of Adelaide in South Australia. It is estimated to be one of the worldÆs top five copper orebodies by size and the biggest single occurrence of uranium. The deposit was discovered by Western Mining Corporation in 1975. Exploration was based on a conceptual model for the formation of sediment hosted copper deposits together with gravity and magnetic anomalies.The capital cost of the current expansion is estimated to be A$ 1.64 billion. The underground expansion includes a total of 36 km of lateral development, a railway haulage system delivering ore from a series of ore passes to a new crusher station and a significant increase in ventilation capacity and mine services.In the current underground expansion the mining method will essentially remain unchanged. The ore handling system will incorporate some recent advances in technology, improving efficiency and safety standards.Major infrastructure excavations are designed by a team of engineers attached to the Olympic Dam Expansion Project and a number of consulting groups. Once the expansion is fully completed it is expected to increase the current annual underground production level from 3.4 Mt to 9.0 Mt of ore by the year 2000. Mine design engineers working for the Olympic Dam Operation have recently completed a three year final design plan to achieve this target.Access to the existing mine is through the decline and Whenan shaft. The Whenan shaft was originally sunk as an exploration access and later upgraded for hoisting. The 4 km long service decline connecting to the Whenan shaft was later constructed to accommodate the increase in service demand. The Robinson and Sir Lindsay Clark shafts were developed at later stages to cater for the hoisting during and following the expansion lead up.

Jan 1, 1999

By Yuan Le, Dominic Reda, Vojtech Ernst Gall, Kurt Zeidler, Tomasz Kecerski

High Speed 2 (HS2) mandated that Building Information Modelling (BIM) processes be implemented during design and construction. Gall Zeidler Consultants (GZ) was responsible for developing the BIM Models for the portals, tunnels, and cross passages of the of the 16 km-long Chiltern twin-bore Tunnel. In addition, GZ developed the GBR for the Chiltern Tunnels and incorporated the relevant information into the Project’s BIM framework. This paper presents the implemented BIM framework, describes the modelling approach, and discusses the advantages and challenges of implementing BIM, particularly how BIM improved interface coordination and how BIM was used in feasibility assessments of different construction options.

Jun 13, 2023

Norton Co., the world's largest producer of abrasives, is enlarging its proppant operation. Proppants are strong chemical particles used to wedge open rock formations in deep oil wells, thereby increasing the well flow rate, sometimes as much as tenfold. Norton" aluminum oxide-based proppant is rapidly displacing less durable materials. The company is building the world's largest proppant plant in Fort Smith, AR. ALUMINUM--See also REFRACTORIES The price of primary aluminum ingot was increased by several producers in July. Kaiser Aluminum & Chemical Corp., and Revere Copper & Brass Inc. increased the price of primary aluminum to 63.0 cents per pound, effective July I. Reynolds Metal s Co., Anaconda Aluminum Co., Howmet Aluminum Corp., and Marti n Marietta Aluminum Inc. increased the price of 99.5% primary aluminum ingot to 63.0 cents per pound, effective July 5, The Aluminum Company of America increased the price of aluminum ingot to 62.5 cents per pound, effective July 9. The range of prices at the end of the month was 58.5 to 63.0 cents per pound.

Jan 1, 1979

By E. T. Bowers

Pneumatic conveying of coal underground is not widely used in the United States, although it is becoming increasingly popular in Great Britain, the Federal Republic of Germany, and South Africa. The question of safety has been raised repeatedly: Will the system be prone to dust or gas explosions, and, if so, can it withstand such occurrences safely? The work reported here was done under a Bureau of Mines contract and deals with the safety aspects of pneumatic transport of underground coal, as well as the hazards inherent in more conventional haulage systems. Included are three designs for different applications of pneumatic haulage: off-loading a continuous-mining machine on a room- and-pillar section, vertical hoisting through a 1,200-ft shaft, and off-loading a tunnel-boring machine driving a 2,000-ft tunnel.

Jan 1, 1985

By Smortchevskyk N. J.

THIS paper describes the electrical features of the locomotive now (August, 1962) under construction for Craigmont Mines. Intended for non-specialists, it avoids details of design and calculations interesting to electricians only. The paper is divided into three sections. The first deals very briefly with the mine layout and with operating conditions -existing and expected. Reference is made to economic considerations leading to the selection of the type and size of locomotive, as well as to traction diagrams and the calculations. This material is not included in the paper because of its length and because it does not represent anything new. The second section deals with engineering and economic considerations and shows, in some detail, why the A.C. system was chosen. The third section describes the basic components of the locomotive, including the voltage regulator, the rectifiers, the control arrangement and the filter, and deals with considerations affecting the selection of their rating and design. A concluding sub-section describes, very briefly, the track and trolley details and the power distribution switchgear.

Jan 1, 1963

By J-F. Béland, N. Parson

Aluminum extrusions are widely used for automotive crash management systems due to their superior specific energy absorption capabilities, as compared to steel. The Al-Mg-Si alloy series can be readily extruded into complex multi-hollow profiles, as required in crash systems, and can be used to target a range of desired strength levels. This paper focuses on the development of an axial crush test protocol and evaluation of the crush performance of common 6XXX series alloys for a variety of tempers. The observed crush behaviour is then compared to tensile test results.

Jan 1, 2015

By A. McEachern

At the Annual Meeting of this society, held in Halifax last year, a paper entitled "Closed System Breathing Apparatus" was read by I. C. Mackie, metallurgist, British Empire Steel Corporation. Coming from such an authority it was most instructive and illuminating. The purpose of the paper was to emphasize the necessity of a full supply of oxygen and the danger of oxygen shortage in the use of rescue breathing apparatus. In connection with this he pointed out: "In times of emergency, when life is at stake, rescue men cannot be restrained from using their utmost endeavor, and unless the apparatus is adequate to meet the heaviest load, the result may be fatal to the wearer. The body's demand for its oxygen requirement is absolutely imperative and must be granted at once. We can do without food for many days and without water for many hours, but we cannot do without full requirements of oxygen even for a few minutes. Furthermore, the victim of oxygen shortage gets practically no warning. He may fall helpless or unconscious before realizing that he is in a serious condition." Hence the necessity for expelling all the nitrogen from the breathing-bag and filling it with pure oxygen; also filling the lungs of the wearer with oxygen before he begins to use the breathing apparatus. This practice is general at all the collieries under the British Empire Steel Corporation.

Jan 1, 1924

By O. J. Tassicker

The Electric Power Research Institute (EPRI) initiated a program in 1976 to develop and demonstrate an instrument system for on-line continuous measurement of coal properties. The program has focused on the use of Prompt Neutron Activation Analysis (PNAA) for elemental determinations and microwave absorption for moisture determination. One of the major results of the EPRI program is the development of the CONAC (Continuous On-Line Analysis of Coal) instrument, with Science Applications, Inc. (SAI) as the prime contractor and Kennedy Van Saun Corporation as a subcontractor.

Jan 1, 1983

The Broken Hill Proprietary Company Limited (BHP) started as a silver-lead-zinc mining company in Broken Hill, New South Wales, Australia in the 1880s. Since then it has diversified into the resource industries of steel, iron ore, coal, petroleum and copper. BHP World Minerals is a Business Group of BHP which is one of the worldÆs largest and most diverse mineral resource enterprises. BHP supplies raw materials for steelmaking, copper concentrate and other mineral commodities to customers in more than 45 countries. BHP World Minerals has operations spread throughout the world û in Australia, the United States, Brazil, Zimbabwe and Canada. Commodities produced by BHP World Minerals currently include silver, lead, zinc, titanium minerals, platinum group metals and coal. The BHP World Minerals Cannington silver-lead-zinc mine in Queensland, Australia is a return to the cradle of BHPÆs early silver-lead-zinc years. This paper compares the success factors and challenges at Broken Hill and Cannington.

Jan 1, 1998

By Fabio Mielli

In these times of increasing costs and diminished returns, energy consumption is one source of savings that remains relatively untapped in the mining sector. Typically, 15% to 40% of operational costs can be attributed to energy in mining operations. This ?process variable? is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. A mining company able to successfully embrace an energy efficiency program is more often than not a successful mining company. Production optimization programs, relatively common today, provide increased production, increased availability of assets and, in many cases, improved quality. They generally ignore the energy question altogether. Production Energy Optimization combines reductions in energy consumption with production improvements to reduce the cost per unit of production while improving emissions reporting. An energy strategy in mining and mineral processing operations is a critical component of Production Energy Optimization. This strategy must support the financial and operational integrity of the business. Developing a successful energy strategy requires a well structured approach such as following: ??Understanding where energy is being used and why, ??Recommending and implementing energy conservation measures, ??Driving visibility to targets and results, ??Re-evaluating continuously. The objective of this paper is to help you better understand the process, tools and technologies that enable mining organizations today to address energy and sustainability issues more tactically and proactively.

Aug 1, 2013

By Chris Twigge

The paper point out development and successful commercial introduction of new technologies into a metalurgicall. The discussion that follows examines the overall issues of implementation from a management perspectiva and will highlight areas where key success factors are often overlooked. The framework presented is structured around the following key themes: The prime incentive for introducing new technologies is broadly one of economics, the implementation of new technologies is, to a large degree, a process of risk management and although the implementation of new technologies revolves around technical and economic issues, in the end the decisiva factor is people. Proper recognition of the human factors is critical to success. In this sense, the above principles are discussed in the sections that follow and include a number of examples to illustrate how technology can be successfully implementad and how it can fail.

Oct 6, 1999

In the past decade, the increased engagement of business in debates around sustainable development has prompted recognition of the importance of biological diversity at the local, national and global scales. Driven by increasing populations that demand rising real incomes, a range of human induced pressures are modifying natural habitats and diminishing their ability to support life. Public policy changes have struggled to arrest the loss of habitats such as wetlands or tropical forests, and the related extinction of plant and animal species. Although conservation legislation and regulation were once the exclusive responsibility of government, new partnerships are now being forged that increase the role of the private sector and non-government organisations (NGOs) in developing and delivering conservation initiatives. Since the mid 1990s Rio Tinto has had to adapt to meet the demands of a rapidly changing conservation landscape. When Rio Tinto adopted its statement of business practice in 1998 The way we work, it explicitly recognised the need to take account of relevant environmental factors in obtaining access to lands, particularly in designated areas of high conservation value. With the revision of The way we work in April 2003, the policy on land access was strengthened through removal of the word ?designated?, thereby signalling recognition of the importance of biodiversity outside of protected areas. In addition, Rio Tinto?s revised land access policy explicitly refers to the use of land that is surplus to operational requirements for habitat protection and biodiversity conservation, subject to social considerations. In late 2003 Rio Tinto further strengthened its commitment to biodiversity with the promulgation of its biodiversity strategy and related position statement, biodiversity principles? (See Appendix 1.1) and technical guidance documents. This commitment is also embodied in a variety of initiatives at the corporate and operational levels, which are reported on annually in Rio Tinto?s Social and environment review. This guide has been prepared to support the practical implementation of Rio Tinto?s biodiversity strategy. The purpose is to provide guidance on how to effectively integrate biodiversity into Rio Tinto?s operations. It is applicable to all Rio Tinto exploration, new development projects and operations, irrespective of whether they have been operational for some years or are at the beginning or end of their operational life cycles. This guidance has been developed to support the Rio Tinto Environment Standards and the Rio Tinto Community Standard and any additional supporting documents as they are developed.

Apr 1, 2005