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By Guilherme Guidugli

The hot blast stoves are a regenerative heat exchange system, accounting for 10 to 20% of the total energy requirement in an integrated steel plant, responsible for the supply of about one-third of the blast furnace heat input and responsible for a constant flow of hot air to the blast furnace, according to the required production. Because of their important role in the hot metal production, a stable operation and an appropriate combustion control is necessary. This paper aims to present the results of an investigation and modifications performed as an operating multi-furnace plant, as well as the parameters considered to ensure thermal equilibrium, improving in the stoves heating cycle.

Aug 16, 2017

By R. R. Sayers

Although the attention of those interested in diseases peculiar to mining as teen focused recently on one duct disease - silicosis - other respiratory diseases may cause more suffering and economic loss. The increased incidence of these diseases usually is attributed to exposure to abnormal air conditions underground, such as sudden changes from high to low temperatures, excessive dust, and noxious gases. The principal respiratory diseases to which the mine is subject axe bronchitis, influenza and pneumonia, pulmonary tuberculosis, anthracosilicosis, and. silicosis. Although the mortality statistics in some of the tables included in this paper are old they have been corroborated by later, lees complete data Bronchitis Bronchitis is en inflammation of the bronchial tubes due, among other causes, to the inhalation of irritants such as dusts (organic and inorganic). Occupations that entail exposure to atmospheres polluted, by irritating gases carry with them the risk of bronchitis. According to Collie (1), it cannot be distinguished clinically from bronchitis occurring among the general population, and its association with tae inhalation of dust or gases usually is unrecognized.

Jan 1, 1941

By S Bhandari

A model for predicting dust plume dispersion from blasting operations using the Eulerian mathematical algorithm has been developed. This model considers atmospheric stability, and wind velocity and direction for computing dust concentrations at different distances from the blast. Software has been developed which simulates the movement of a dust plume at a given horizontal distance from the blast location and time elapsed after the blast. The concentration of dust is also given in vertical planes. It takes into account ground profile and atmospheric conditions such as temperature, pressure, humidity, wind velocity, wind direction and shear. Experiments were carried out in two limestone mines to calibrate the accuracy of the predictions made by such model. High volume dust samplers were used to collect dust samples. Difficulties encountered in satisfactory dust sampling and quantification of results have been described.

Nov 8, 2011

Rosebery Mine is situated on the west coast of Tasmania and is AustraliaÆs largest volcanic-hosted base and precious metals deposit (zinc, lead, copper, gold and silver). The milling operation has been producing zinc, lead and copper concentrates continuously for over 100 years. RoseberyÆs long life demonstrates the operation to be high grade, and high margin, capable of operating through several commodity price cycles. Paradoxically, throughout this long history the ælife-of-mineÆ as defined by proven and probable reserves has been short. Zinifex has demonstrated its commitment to discover the future of Rosebery with the growth project æProject HorizonsÆ. The aim of the project is to extend the life of mine beyond 2020, with an additional exploration expenditure of $19 million over three years. Despite the maturity of the deposit, early success has confirmed the potential with the discovery of new resources. Mine planning strategic studies are challenging established paradigms of mine production, throughput rates and metal cut-off grades. Discovering the optimal process rate for Rosebery, by examining the æHill of ValueÆ and underground mine optimisation is proving critical to the best exploitation of RoseberyÆs rich resources. The promise of finding a mine within a mine is being realised, with new lenses being delivered by exploration success and real grade/tonnage options optimised through dynamic mine planning. The future of Rosebery is co-dependent on these two areas of discovery. This ensures capital expenditure decisions are informed, to secure the next 20 years of wealth creation and beyond.

Jan 1, 2008

By J. R. Patts, L. D. Patts, S. J. Janisko, T. Barone

"Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more efficient and effective use of rock dust. A prototype, flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed in line between the ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over a period of three days at set distances from the fan exhaust to assess the changes in float coal dust levels in the return due to the operation of the scrubber. Mass-based measurements were collected on a per-cut basis and were normalized per foot of advance by the continuous miner. Results show that average float coal dust levels measured under baseline conditions were reduced by over 91% when operating the scrubber. INTRODUCTION In 2012, underground mining in the United States produced over 342 million tons of coal [EIA 2013]. During the cutting, crushing, and transport of this coal, dust is generated and can be entrained in the air ventilating the mine. Title 30 Code of Federal Regulations Part 75.400-1 (30 CFR§ 75.400-1) defines float coal dust as particles of coal that can pass a No. 200 sieve. These coal particles can be carried by the ventilating air into return entries before settling onto mine surfaces [NIOSH 2006]. If this float coal dust becomes re-entrained into the airstream, it can propagate an explosion throughout mine workings [Harris et al. 2010]. Application of rock dust in underground coal mines is required by Federal regulation as a means of preventing the propagation of explosions by float coal dust. In order to meet Title 30 Code of Federal Regulations Part 75.403 (30 CFR § 75.403), 80% incombustible content must be maintained in the composition of dust deposited in mine entries [76 Fed. Reg. 35968 (2011)]. This fraction of incombustible content is increased if elevated levels of methane are present. In order to maintain the required incombustible content, frequent or constant application of rock dust is undertaken by mine operators. Title 30 Code of Federal Regulations Part 75.2 (30 CFR § 75.2) defines the properties of the rock dust that must be used by mine operators."

Jan 1, 2015

By Leon Lorenzen, Victor E. Ross, Anton W. Kleingeld

Key to successful innovation, whether at organization, industry or national level, is the alignment and utilization of resources in the most appropriate and efficient way. Innovation needs to be directed strategically, and it needs to be auditable in a systematic and integrated fashion. In the light of these considerations, this paper describes the construction and use of a topographical map of the innovation landscape. The purpose of the map is to provide a holistic view of the key factors that enable innovation (the so-called ’landmarks’), how well they are aligned to support a particular type/nature of innovation in the organization, and to identify possible gaps. The significance (importance) and height (performance) of the landmarks in supporting and enabling innovation within the organization is determined by means of a selfappraisal audit. The topography of the landscape derived thus is subsequently interpreted in terms of the organization’s particular innovation strategy and environmental context. The application of the Innovation Landscape Methodology is illustrated in a number of organizations within the Mining and Minerals Industry of South Africa. Important observations and conclusions regarding the strategic alignment of enabler strengths within these organizations are made.

Jan 1, 2003

By R. Adsero

The volume of data produced by operating mines has increased substantially over the last 10 years. However, the volume of data and analytical capability has been negatively correlated to equipment productivity for at least the last seven years. In simple terms, as the volume of data has increased equipment performance has declined. Table (2010) tells us that ?The calamity of the information age is that the toxicity of data increases much faster than its benefits?. More data does not guarantee improving productivity; but more data is also not the cause of declining productivity. Similarly, when equipment performance does start to improve, (it must ? there really is no option if mines want to remain competitive), it will not be the data nor analytics which causes it; it will be the people using the resources at their disposal; including the data. Data and analytics can help if the toxicity of the data can be managed. The simplest form of business improvement using data is benchmarking. The objective of benchmarking is to understand and evaluate the current position of a process in relation to ?best practice? and to identify areas and means of performance improvement. The application of benchmarking involves four key steps: (1) Analyze and understand in detail existing processes; (2) Analyze and understand the processes of others; (3) Compare your own performance with that of the others analyzed; and (4) Design and implement the changes necessary to close the performance gap(s). There are however, many in the mining industries who have shunned equipment benchmarking because they believe that, ?every mine is a pilot?. In other words, the differences between mine operations make comparisons between them of little value. This paper will present a valid approach to benchmarking equipment performance and reliability, accounting for the differences and similarities between operations, producing a result which can be used to add value to mines around the world.

Feb 23, 2014

By M Wagner, H Assimi, F Neumann, C Garcia, B Koch

Run-of-Mine (ROM) stockpiles are the inventory of valuable materials extracted from the mine. Depending on the customer requests, a selective addition of ore from stockyards should be selected at the required tonnage. In the stockyard, stackers and reclaimers are the machines which load and unload ore, respectively. Currently, humans determine the reclaiming/stacking planning sequence in the stockyard by rules of thumb. However, this is a complex task subject to multiple operational constraints, such as where undesirable mineral properties should not exceed certain limits in a request. Human planning can lead to limited decision support and lower ability to consider the upcoming blends and requests. This kind of decision making can cause perturbations in the assumed profit and unexpected loss in practice. Therefore, an intelligent decision-maker and sequence planner would be highly valuable to automate stacking and reclaiming operations in practice. The benefits are reducing variability in decision-making and operation costs. This paper considers a stockyard with available mineral information in the stockpiles using load and dump locations from GPS data feeds. We present an optimisation problem to find a solution which results in reclaiming more ore in a shorter time. To solve the problem, we develop an automatic search strategy based on the greedy search algorithm independent of the type of machine used in reclaiming. The proposed method plans a sequence for stockyard recovery blend optimisation to meet multiple customer demands in a timeframe. Blend optimisation is subject to various constraints such as the elemental composition of the valuable materials and penalty elements. We present three case studies using EKA’s simulator, to fulfil two to four requests from four stockpiles. We compare the obtained results with a pilgrim step reclaiming heuristic and we show how our proposed search strategy outperforms the current strategy used in practice.

Nov 10, 2020

By H. B. Gillis

THE following pages c9ntain a brief description of the processes involved in the manufacture of silica brick at the Sydney plant of the Dominion Steel & Coal Corporation. Silica brick manufacture was commenced at Sydney in 1918, for the purpose of supplying the requirements of the steel plant, where about three million silica bricks were used annually. Previous to that date, all silica refractories were brought to Sydney from American sources and were subject to a freight cost of nine dollars per ton, or about twenty-seven dollars per thousand. As a preliminary step to manufacture, a thorough investigation of all possible sources of silica in the vicinity of Sydney was carried on during 1916 and 1917. ?Eighteen separate deposits were examined. Of this number, only four were found suitable for brick making, and the Leitches Creek silica, being the nearest of these four deposits to Sydney, was selected as the raw material for the proposed plant. CRYSTAL MODIFICATIONS OF SILICA A brief review of the silica minerals may serve to indicate why careful investigation of sources of supply is necessary before actual brick-making is attempted. The crystal modifications of silica, i.e., quartz, tridymite, and cristobalite, all possessing alpha and beta phases, play a most important part in determining the suitability or otherwise of the resulting brick. By heat treatment, any one of these forms of silica may be converted to either of the others. The inversion temperatures (after Fenner) in degrees Centigrade are shown on rage 160.

Jan 1, 1938

By Lorenzo Reyes-Bozo, Ronaldo Herrera-Urbina, Pablo Higueras, Alex Godoy-Faúndez

"The copper mining industry in Chile and perhaps in other countries as well is faced with the challenge to implement the best practices in order to achieve a sustainable and more environment-friendly growth. Relationships between mining industry and society have been historically complex due to its environmental impacts. Whereas the ore grade has declined continuously, this has involved an intensive energy and water consumption thus increasing operational costs at different stages of the concentration process. In the case of copper sulphide ore concentration, froth flotation is the main technology used worldwide. The amount of the different chemical reagents used in flotation plants (i.e., collectors, depressants, frothers and modifiers) affects significantly production costs and has a negative effect on the environment as well. The objective of this research work was to evaluate the use of biosolids and their main components (i.e., glucose, proteins and humic substances) as more environment-friendly flotation collectors for chalcopyrite and molybdenite. For this purpose, microflotation tests were conducted in a modified Hallimond tube. In addition, FTIR and zeta potential experiments were performed to investigate the interaction of biosolids with these sulphide minerals. Biosolids and their main components may interact through physical and chemical ways due to different affinities with such sulphide minerals as chalcopyrite, pyrite and molybdenite, which are present in copper sulphide ores. In alkaline pHs, biosolids and their main components make the zeta potential of the sulphide minerals investigated more negative. These results may provide important information concerning the behavior of the main sulphide minerals in the concentration of copper sulphide ores at industrial scale, wherein mill processes could affect their surfaces properties. Therefore, biosolids and their main components may open an opportunity to be used in copper sulphide flotation plants to partially replace conventional reagents, which are more hazardous and less environment-friendly."

Jan 1, 2014

By J. A. Kost

A dust-control manual was prepared for use by mine operations personnel. The manual documents state-of-the-art control techniques, dust sampling, and use of personal protective devices. Content addresses advantages/disadvantages of control techniques, design and operating specifications, and implementation and maintenance guidelines. An indexed list of selected references is also included. In addition to the completed manual, this report documents work performed in the course of its preparation.

Jan 1, 1981

By V. R. Shea-Albin

This U.S. Bureau of Mines report discusses elastic wave velocity and attenuation behavior as an indicator for changes in load and structural integrity of coal samples. Measuring changes in compressional (P)-wave and shear (S)-wave attenuation and velocity under uniaxial and triaxial compression tests revealed their effectiveness for distinguishing changes in applied load and structural failure of samples. The velocity and attenuation values were used in further calculations such as ratios of P-wave to S-wave values, dynamic elastic constants, normalized velocities, and attenuation coefficients to reveal trends for loading and failure. The behavior of both P-wave and S-wave attenuation and velocity together define distinct and consistent phases of load change and failure for uniaxial and triaxial tests. The S-wave velocity and attenuation illustrate changing axial load and initial development of microfractures within the sample preceding structural failure more clearly than those of the P-wave. The attenuation and velocity ratios and dynamic elastic constants (except the bulk modulus) respond to closure of small preexisting fractures within the coal sample with initial loading to failure of coal samples. The attenuation coefficients and normalized velocities reveal trends similar to those shown by velocity and attenuation.

Jan 1, 2010

By Sydney H. Ball

It is a peculiar anomaly that while the world uses the term "rich as a gold mine" as the superlative figure of speech descriptive of wealth, the shares of gold mines are not as popular investments in America as certain of them should be. One of the most able of Manhattan's bankers is a director in an investment trust with a portfolio the value of which has gone the way of other such portfolios. Luckily a couple of years ago a few hundred shares of Homestake were purchased, and since then the trust has not only received therefrom satisfactory dividends but has benefitted from a large appreciation in their value. At each directors' meeting, however, the banker in question, Cato-like, suggests the sale of these shares, gold shares being, in his opinion, too speculative to be included in the portfolio of any trust. A short time ago the financial pages of one of our great metropolitan papers featured an article listing the corporations still paying dividends at the 1929 rate. Gold-mining shares were, the article stated, excluded, although in reality every gold mine on the New York Stock Exchange paid higher dividends in 1932 than in 1929. This 'Alice in Wonderland' treatment of the gold-mining shares is admittedly a bit confusing to those of us who believe that the shares of certain gold-mining companies have a rightful place in any well diversified portfolio. It should, however, here be recorded that whereas, fifty years ago, in America, gold-mining shares were considered by the public as instruments of nefarious gambling, now shares of the better gold mines are sought by astute investors. In England for well over a generation their value as sound investments has been widely recognized.

Jan 1, 1933

The National Mining Hall of Fame and Museum (NMHF&M) will induct its the 2014 National Mining Hall of Fame Class on Sept. 13, 2014 during its 27th Annual Induction Banquet and Ceremony at the Westin Hotel in Denver, CO. Representing the domestic and worldwide metal production, education, and health and safety sectors of the industry, this year?s four inductees cover a diverse cross-section of the mining industry. Harry M. Conger III, Günther Franz (Frank) Joklik, Ellen Swallow Richards and Dr. Alfred Weiss will join 223 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame. They were selected for being visionaries, leaders and ambassadors, both within their own sectors and across the industry at large. Conger was a great role model and strong advocate within Homestake Mining Co. and among his industry peers on behalf of environmentally responsible, safe, profitable and high-performance operations. As chairman and chief executive officer, Conger was instrumental in revitalizing and rebuilding Homestake into an industry leader in technological advances and environmental protection. Through his contributions in exploration, project development and operations management as Kennecott president and chief executive, Joklik did much to strengthen Kennecott as a company and assisted in restoring the competitiveness of the U.S. mining industry. Richards is generally recognized as the founder of ecology. She was the very definition of a pioneer in such diverse fields as chemistry, geology and mineralogy, mining and metallurgy, environmental science, public health, home economics and education. Weiss was a true visionary in using quantitative methods and digital computers to aid mineral exploration, plan and design mines, operate mineral production facilities and integrate the disparate information resources throughout a mining company into a modern management information system. NMHF&M Board of Directors Chairman, Paul C. Jones, said, ?Again this year we are honored to be able to induct an outstanding group of deserving individuals who have made exceptional contributions to the mining industry in the United States. Included are two living inductees who have made significant contributions to management in the industry. One inductee was the first female graduate from the Massachusetts Institute of Technology, its first female faculty member and the first female member of AIME who had an outstanding career as a mineral investigator in the United States. Another inductee was a lifetime innovator in bringing digital technology into common use in our industry. Each of our 2014 inductees made significant and lasting contributions to our industry and are well deserving of becoming a member of the National Mining Hall of Fame.? The Hall of Fame Induction Banquet and Ceremony is a marquee event for the National Mining Hall of Fame and Museum each year. The 27th Annual Induction Ceremony and Banquet will be held at the Westin Hotel in Denver, CO on Saturday, Sept. 13, 2014. For banquet reservations, contact the NMHF&M office at 719-486-1229. More information is available on the NMHF&M website at www.mininghalloffame.org.

By J Rostami, T Afshar, M Sharifzadeh

Accurate estimation of rock load and selection of types of ground reinforcement to match post-failure behaviour of rock mass are important issues to assure tunnel stability. This paper focuses on the main factors affecting rock load to evaluate the capabilities of the existing models for prediction of rock load. Rock mass properties, project features and excavation method, as well as ground conditions and stress condition were found to be the key factors affecting the magnitude of rock load. Field data from tunnels of about 37.5?km driven in several geological structures in non-squeezing ground was used in this study. An in depth statistical analysis was performed on data to find correlations between the input parameters and measured/observed rock load. A weighting system was proposed to obtain the proper contribution of each factor for estimation of rock load in tunnelling through various ground conditions. The new classification system offered predicted values for rock load that were in a good agreement with the actual field measurements. The high disturbance factor (D>0.4) was the prime factor which controlled the rock load. Rock mass quality was the second key factor influencing rock load, which could be estimated by GSI, GSIresidual , especially when combined with tunnel depth.CITATION:Afshar, T, Sharifzadeh, M and Rostami, J, 2014. Estimation of rock load for tunnels with different disturbance factors, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Congling Shi, Marek Borowski, Yue Wang, Jianwei Cheng, Xixi Zhang, Xuan Xu

As the first barrier to prevent accidents caused by explosions in underground coal mines, the integrity and stability of mine seals have great effects on mine workers’ lives and underground production safety. In this paper, the mechanical responding performance of typical mine seals under the impact load are studied by using numerical simulation method. By such simulation studies, the safety of different seals subjected to the explosion load is evaluated. Seals’stability are also investigated under effects caused by various influence factors including thickness of mine seal, cutting depth into surrounding rocks, rock type, and the roof-tofloor convergence under given the explosion load. The research results can provide theoretical basis and reasonable improvements for mine seal’s construction practices for improving its anti-explosion performance.

By Stephen W. Denton

Planning a mining operation in Alaska will involve the investigation of many parameters common to mine planning anywhere. However, there are some unique circumstances that must be recognized when one considers development of mining operations in Alaska. This paper will not attempt to provide a blueprint for mine planning in Alaska, but hopefully will provide a better understanding of the truly unique nature of the northern latitudes. Given this understanding, the mine planner can better assess the potential hurdles along the road to a successful mining operation. The regulatory trend towards uniform standards for mining throughout the United States exemplifies the necessity for Alaska to prove its unique position in the natural resources picture. The factors which make Alaska truly different from the "Lower 48" can be summarized by four points 1) Remoteness and Size 2) Seasonable Extremes 3) Geologic Immaturity 4) Vegetation and Wildlife

Jan 1, 1984

By S. Stoyanov, M. Cross

"Silicon components containing transistor circuitry are at the heart of electronic products such as computers, mobile phones, etc. These components are connected to printed circuit boards (PCB's) using solder material that acts as the conductor for both electricity and heat. During the lifetime of a product it will undergo many thermal cycles where the chip becomes hot during product operation and then cools when the product is switched off. At the product design stage engineers undertake thermo-mechanical simulations to predict the thermal stress in the solder joints due to this thermal cycle and to ensure that the stress magnitude will not result in early fatigue-type failure. The design engineer's aim is to identify component parameters which ensure that the solder will survive beyond a certain number of thermal cycles.The aim of integrating computational mechanics and optimization tools together is to speed up dramatically the design process. From viewpoint of a design engineer in the electronics manufacturing sector, these tools can be used to quickly estimate key design parameters (i.e. material properties, product dimensions, etc) that will guarantee the required product performance. In this paper a modeling approach coupling computational mechanics techniques with numerical optimization is presented and demonstrated. The integrated modeling framework is obtained by coupling the multi-physics framework - PHYSICA - with the design optimisation tool- VisuaLDOC. Thermo-mechanical simulations are presented that predict the creep strains in solder material. Different numerical optimization procedures: Direct and Response Surface based optimization plus Design of Experiments, are tested as a part of this modeling framework."

Jan 1, 2001

By T. G. Carter

"Tremendous progress has been made in recent years towards developing computational tools that allow ready solution of most common rock engineering problems, with amongst the most advanced of the tools focusing on evaluating engineered openings within Synthetic Rock Masses. These new codes have the potential to allow much more realistic design, but they must not be used without careful calibration – prior to – during and – post completion of any modelling. This paper explores some of the pitfalls of inadequate data collection and suggests more emphasis be given to calibration. Guidelines for minimum levels of parameter data are suggested for improving application of basic to sophisticated modelling codes.INTRODUCTION & BACKGROUNDTremendous progress has been made in recent years towards developing computational tools that allow ready solution of most common rock engineering problems. The degree of sophistication now possible with some of the available codes allows one to tackle extremely complex problems that were not thought tractable even a decade ago. Indeed, generation of synthetic numerical rock masses, based on discrete fracture network representations that closely mimic actual rock mass conditions, such as are shown in Figure 1, is today relatively straightforward, and not as user-challenging as employing state-of-the-art codes of even a few decades ago. This is largely because major improvements in computer graphics and in availability of ready-made user-friendly input-output interfaces have paralleled development of these new codes, now in some cases outpacing actual new analytical/procedure developments. This is something of a reversal from the first few decades of DOS-based rock engineering computational experience, when only rudimentary graphics were available and user-friendly input-output interfaces were virtually non-existent."

Jan 1, 2015

By Stephen G. Mlot

The evaluation of mineral projects involves the identification, mitigation and management of significant uncertainty. Benchmarking is an essential and effective way of increasing confidence and reducing uncertainty associated with input parameters and assumptions. Comprehensive and detailed benchmarking will ensure ?best practice? technologies, methods and systems have been considered and that the appropriate practices can be identified and incorporated into the project. In conjunction with the involvement of experienced industry practitioners, benchmarking is best employed throughout project evaluation to enable early identification of ?errors?, producing more accurate and predictable outcomes. Considerable time and effort is required to gather data and information, which should be benchmarked by the project evaluation team. There is a history of mining projects underperforming, on production, on costs and on return to the investors. The quality of mine plans and feasibility studies, and the quality of the input data is being questioned in many ways. Benchmarking assists sound project evaluation practices, by providing a database of actual results, to validate project inputs and outcomes, ensuring they are realistic and achievable. Benchmarking also provides unbiased, statistical support as the basis for sound investment decision making and ensures well considered decisions are made resulting in a more efficient study process. The evaluation of the quality of projects which are the subject of transactions also benefits from the use of real data obtained from a benchmarking database. Vendors are quick to highlight the benefits of their projects, and conceal the flaws, inflating the value. Buyers will want to quantify the potential of a project through the due diligence process relying on actual results from benchmarking. For the reasons broadly outlined above, benchmarking should be considered as an essential component of effective Project Evaluation.

Aug 1, 2013