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By Claudio Fabbro

The increasing demand of wire rod high carbon grades for both small and large sizes are challenging the wire rod producers to enhance new technologies by combining high plant productivity and efficiency of superior quality finished products with extreme process flexibility. The possibility to change process route according to the final application of the rolled steel grade and to simplify production planning is one of the most important keys to success that distinguishes the mill plants developed by Danieli. This paper will focus on the most important metallurgical and process targets and on the in-line heat treatment technologies representing the core of Danieli know-how on high carbon grades production.

Jul 30, 2018

By Michael J. Rosko

Methods have been developed for processing and analyzing reflected solar radiation data obtained by Landsat 5 Thematic Mapper multispectral scanner. Spatial resolution for the Landsat series satellites is 30 meters per side per pixel. Materials on the Earth?s surface absorb or reflect different parts of the electromagnetic spectrum depending on their physical and chemical properties and, therefore, typically have characteristic spectral ?signatures?. Using these signatures, environmental parameters such as surface water and vegetation may be identified and analyzed. Principal advantages of the satellite image method for environmental monitoring include: a relatively long historic period beginning in 1985 for which information is available, the reliable numerical basis for the results, and the ability to assemble a historic environmental baseline and provide on-going monitoring for large or remote areas where standard monitoring methods may not be practical. However, because the long-term continued operation of Landsat 5 is problematic due to the age of the equipment, QuickBird and IKONOS satellite images were processed to determine if the two systems are sufficiently similar in their results to allow continuing monitoring using QuickBird data. The QuickBird satellite was launched in 2001 and collects the same visible and near infrared spectral bandwidths as Landsat 5, allowing for equivalent process algorithms for QuickBird, IKONOS, and Landsat 5 data. Spatial resolution for the QuickBird images is 2.4 meter per side, allowing for more detailed characterization of the land surface; spatial resolution for the IKONOS images is 4 meter per side. Because of several differences between the satellite systems, including degradation of the Landsat 5 sensor, it is necessary to calibrate QuickBird and IKONOS results to the Landsat results to verify similarity. Recent images from the satellite systems have been processed and results have been compared to determine the validity of comparing Landsat 5 and QuickBird/IKONOS images so that these newer data can be used reliably in the future instead of Landsat 5 data. Results from this comparison are presented in this paper and suggest that analyses for vegetation using the two satellite systems are comparable, and that little calibration is required. Results from comparison of surface water results from the two systems are less comparable and is currently being investigated by the authors.

Oct 1, 2009

By Brian E. Perrine

Underground mining requires a variety of specialized equipment. With ever-changing mining conditions and methods, some mines have had to resort to purchasing existing industrial equipment and adapting it for underground use. Since this equipment is not made for underground mining or their specific task, the result is often lost time, money, and sometimes an unsafe working condition. One such application is the setting of a CAN. A CAN is a type of cylindrical secondary roof support made from a cement composite and encased in steel. The CAN has become popular because of its simple one-piece design that can handle heaving and sagging better than other available designs. ?Because of this exceptional ability to sustain load through extended convergence and displacement, the CAN is one of the most robust and stable standing supports in use today.?It also promotes better air flow due to the size and shape of the CAN. CAN size and weight have increased over time to handle more difficult mining conditions. Significant down time and inefficiencies with existing CAN setting machines at Twentymile Coal were directly due to the item in use not being designed to be task-specific. They were undersized with very limited movement. The miners had to take extra steps and precautions when setting CANs. Maintenance delays were significant. Twentymile Coal Company realized that they required a safer, more reliable and more efficient machine to handle and set CANs, and looked for a partner to develop a new design-specific machine. They worked jointly with J.H. Fletcher® engineering and sales to design and manufacture a machine specifically made for setting CANs. The objective was to produce a machine that would handle the conditions and methods that the mine required for setting CANs during longwall retreat. The resulting design had to be safe, stable, have a wide range of motion, be ergonomic, simple to use, and easy to maintain. The machine also had to improve efficiency. The resulting machine has been operating for approximately one year at Twentymile Coal and has been proven to improve safety, reliability, and efficiency. In conclusion, with the task-specific CAN Manipulator, the mine is able to better plan daily tasks with the knowledge that the machine will be available throughout a shift, and the employees will be safer because of the machine?s ergonomics, stability and safety. This has resulted in better productivity and a safer environment.

Jan 1, 2013

By T. BoBo

"In the 1990’s metal prices were trending in a long term decline and the usual cost cutting exercises were adopted. Cuts to research and development made innovation difficult and the outlook was grim. But necessity is a strong motivator, and these conditions spurred the Mine-to-Mill movement which optimised across organisational “silos” and utilising new technology tools, innovative software and increased computing power. Many applications of Mine-to-Mill exploited the fact that comminution is usually the site processing bottleneck, and that blasting is more efficient at breaking rock than grinding. This approach sought to: • Understand and characterise rock breakage from mining to the mill • Develop models and simulators for blast design, fragmentation, crusher and mill circuits • Develop tools to measure in real time the particle size distribution of rocks on conveyors and Run of Mine (ROM) muckpiles • Ensure effective communication across the silos between geologists, blast design engineers, mining engineers and metallurgists These methods and the technology tools available in the 1990s were widely adopted at numerous sites around the world with significant benefits. SAG mill throughput increases of 10-20% were common. This was the advance the industry desperately needed. It was low capital cost; it was obvious. It was here to stay. Except, in too many cases, it didn’t. In the minerals price boom of the 2000’s Mine-to-Mill was no longer necessary to “survive”, even though it was still good business. Some operations, including some of the early success stories, slipped back to old habits of optimising within organisation silos instead of across them. Fortunately, other operators still embraced Mine-to-Mill and developed new techniques. Mine to Mill was still successful, but it not as widely adopted as we had expected it to be.Now the boom has ended and operations are again under cost pressure. Since these are the same circumstances that created Mine-to-Mill, it seems time to achieve the wider adoption. Since the 1990s many new or advanced technology tools are available for Mine-to-Mill projects: blast-hole sensors, new explosives formulations, new blasting techniques and modelling, ore tracking devices, improved image analysis to determine size, texture and colour of coarse ore, grade sensors, whole-stream simulation tools, even more powerful computing hardware and data analysis software. If we could achieve so much in the 1990’s, how much more can we achieve today when we have the same imperative, the same potential and a larger number of high technology tools?"

Jan 1, 2017

By J Pease, P Cameron, D Drinkwater

"In the 1990s metal prices were trending in a long-term decline and the usual cost-cutting exercises were adopted. Cuts to research and development made innovation difficult and the outlook was grim. But necessity is a strong motivator, and these conditions spurred the Mine to Mill movement that optimised across organisational ‘silos’ and utilised new technology tools, innovative software and increased computing power. Many applications of Mine to Mill exploited the fact that comminution is usually the site processing bottleneck and blasting is more efficient at breaking rock than grinding. This approach sought to: understand and characterise rock breakage from mining to the milldevelop models and simulators for blast design, fragmentation, crusher and mill circuitsdevelop tools to measure in real time the particle size distribution of rocks on run-of-mine (ROM) muck piles, at the primary crusher truck dump pocket and on conveyorsensure effective communication across the silos between geologists, blast design engineers, mining engineers and metallurgists.These methods and the technology tools available in the 1990s were widely adopted at numerous sites around the world with significant benefits. Semi-autogenous grinding (SAG) mill throughput increases of 10–20 per cent were common. This was the advance the industry desperately needed. It was low capital cost; it was obvious. It was here to stay.Except, in too many cases, it didn’t. In the minerals price boom of the 2000s Mine to Mill was no longer necessary to ‘survive’, even though it was still good business. Some operations, including some of the early success stories, slipped back to old habits of optimising within organisation silos instead of across them. Fortunately, other operators still embraced Mine to Mill and developed new techniques. Mine to Mill was still successful, but not as widely adopted as we had expected it to be. Now the boom has ended and operations are again under cost pressure. Since these are the same circumstances that created Mine to Mill, it seems time to achieve the wider adoption. Since the 1990s many new or advanced technology tools are now available for Mine to Mill projects: blasthole sensors, new explosives formulations, new blasting techniques and modelling, ore tracking devices, improved image analysis to determine size, texture and colour of coarse ore, grade sensors, whole-stream simulation tools, and even more powerful computing hardware and data analysis software. If we could achieve so much in the 1990s, how much more can we achieve today when we have the same imperative, the same potential and a larger number of high technology tools?Citation:Cameron, P, Drinkwater, D and Pease, J, 2016. The ABC of Mine to Mill and Metal Price Cycles, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 349–358 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By C. Jack Powell

TVA's involvement in air quality programs is perhaps a bit unique. The Tennessee Valley Authority was established in 1933 as a regional resource development agency and therefore must view clean air and clean water as essential resources for the overall development of the Tennessee Valley region. TVA operates certain resource development and production facilities, including power-generating facilities, which are potential air pollution sources. The remarks in this paper will be restricted to air pollution control technology at power-generating stations. Perspectives of Air Pollution Control The art of pollution control must be viewed from several perspectives: 1. It must be viewed in a time perspective--what is available now for air pollution control, what might be available in the near future, what are the likely technologies for the more distant future, and what the future trends in availability of resources might be. 2. Each air pollution abatement scheme must be viewed in the perspective of its total environmental consequences--not just its ability to clean up the air. The generation of electricity from coal produces waste gases, waste particulates, and waste heat. These wastes must be disposed of either in water, in air, or on land. If the polluting wastes are removed from the gas streams going into the air, then they must be disposed of either on land or in water or, hopefully, converted into a product which has some beneficial use. As an example, removal of S02 from stack gases could be more readily accomplished if one could dump waste sulfur products in water. He would solve an air pollution problem by creating a water pollution problem. 3. Techniques for air pollution control must be viewed in the perspective of regional, national, and world resources with their national security and economic implications. The power industry might reduce air pollution by switching generating plants to burning desulfurized fuel oil or natural gas.

Jan 1, 1972

This publication summarizes the research (in-house and contract projects) programmed by the Bureau of Mines for fiscal year 1984 (October 1, 1983-September 30, 1984) under its Health and Safety Technology Program. The objective of these projects is to provide an ordered and sequenced advance toward the Bureau's overall goal of providing the systems technology required to create a more healthful and safer working environment for the Nation's mining and minerals processing workers.

Jan 1, 1983

Pilot plants for pressure hydrometallurgy represent special design and project execution challenges unique to the industry and to the pilot- and demonstration-scale. Pilot plant projects have different objectives and shorter timescales than commercial plant projects. Design considerations and strategies, and project execution methods that meet the special needs of pilot plant projects, are discussed. Specific guidance is given for the selection of appropriate pressure and temperature design points for pressure hydrometallurgical process equipment, and for the selection of materials of construction for pilot-scale equipment. The balance between the need for process similarity with future commercial operations and the realities of pilot-scale equipment is also discussed.

Jan 1, 2004

By W. L. Cooley

Electrical accidents occurring in coal mines from 1975 through 1979 were categorized and analyzed. The data was searched for common electrical hazards, common activities on the part of those injured, and common negligent or careless behavior. The most common electrical hazard was abnormal arcs or sparks, the most common injured activity was handling energized trailing cables, and the most common careless behavior was failure to de-energize circuits before working on them. The accident data was combined with mine production statistics to form a normalized electrical accident rate. It was found that some mines have consistently more lost workdays per man-hour worked than do other mines. Bureau of Mines electrical safety research contract expenditures were reviewed to judge whether the research effort was directed to those areas which are related to the most accidents. In some cases it was not. A method was devised and utilized to estimate the relative cost to the mining industry to implement certain safety measures developed through Bureau research, and also to estimate the potential safety benefits. Some safety changes are recommended, others are not. MSHA regulations were reviewed for effectiveness in preventing electrical accidents, and suggestions were made for discontinuing, clarifying, or otherwise modifying the regulations.

Jan 1, 1981

By S. D. Graham

"The extractive metallurgy of gold is largely controlled by mineralogical factors such as the presence of refractory gold, particle size, gangue mineral associations, presence of preg-robbers, oxygen and cyanide consumers, and locking characteristics in base metal sulphides. Light microscopy and automated mineralogy techniques are regularly used to characterise the effect of these variables on gold recovery. However, despite their widespread application there are a range of limitations when grades are low. Typically, the analysis of low-grade samples requires the preparation and analysis of numerous polished blocks. This is often costly and time consuming, with complexities regarding analysing statistically representative particle quantities and problems overcoming stereological bias. This is compounded by the “nugget” effect and high tenor nature of gold mineralisation. X-ray Microscopy techniques have the potential to overcome many of these problems, in particular the statistical representivity of analysis, removing stereological bias and effectively locating phases that are present in ultra-trace proportions. In this paper we outline the potential benefits of employing X-ray Microscopy (XRM) in characterising gold losses from a typical Cu-Au porphyry project, which were illusive in 2D based analysis. The talk will also outline additional application areas of XRM within the extractive value chain."

Jan 1, 2017

By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022

By Breno Carvalho de Oliveira

A prática da manutenção evita a ocorrência de falhas e reduz significativamente os ganhos na produtividade e qualidade do produto. Devido a sua importância, empresas de logística e operações ferroviárias tem buscado através da adoção de novas tecnologias, tornar esse processo mais dinâmico, confiável e eficiente. O presente estudo de caso aborda a implantação do sistema de gestão da confiabilidade Failure Box (FBOX), que utiliza metodologias e técnicas embasadas no tratamento de perdas pontuais e sistêmicas. O resultado deste processo é a padronização, disponibilidade e confiabilidade dos ativos, contribuindo assim para crescimento e otimização do sistema de gestão da manutenção.

Oct 30, 2017

This Bureau of Mines report describes research on methods of assuring the continued safety of mine electrical power distribution circuits through reliability and quality assessment of the protective devices, innovative inspection techniques for these devices and the circuits themselves, novel applications of trolley line circuit breakers, and computer modeling of distribution systems to determine the proper ratings for cables, power sources, and circuit protective elements. Battery charger safety is included.

Jan 1, 1979

By J. M. Figueiredo, A. R. Silva, M. C. Coelho, R. M. Guedes

"With the continuous depletion of conventional sources of non ferrous metals, low grade complex sulphide deposits have been regarded as an alternative source of supply of zinc, copper, lead and also silver and gold. In spite of very important efforts in research in this domain it is still a long way to go in order to achieve reliable technological solutions both in ore dressing and metallurgical treatments which enable these complex materials to be regarded as commodities. The RLE process to treat bulk concentrates such as those obtained from portuguese ores, under development at LNETI and QUIMIGAL premises, combines experienced unit operations and innovative configurations and is an effective contribution for the future use of these materials. The results of three years of experimental work and main conclusions on the overall feasibility of the process are presented.IntroductionIn spite of the very well-known problems associated to the development of complex sulphide deposits, the economical importance of the enormous reserves of these materials, widespread all over the world, is so evident that its future use as source of supply of basic and precious metals and other minor elements is almost unavoidable.Critical steps in that direction are mainly concerned with favourable economical conditions and sound metallurgical practice for the treatment of nonferrous metals concentrates, which are nowadays still considered as non-conventional raw materials.Since Portugal is one of the countries where these orebodies occur more extensively, Portuguese authorities have dedicated since the beginning of the seventies, a big effort on finding economical and reliable processes for the recovery of copper, lead, zinc and also gold and silver, and for this purpose, several alternatives on ore dressing and metallurgical processing were studied, however without full sucess.Five years ago LNETI, a research laboratory, and QUIMIGAL, a chemical company, both state owned, decided to launch a research programme for the development of a metallurgical process for the treatment of NFM concentrates, which received financial support from NATO under its programme ""Science for Stability""."

Jan 1, 1988

By L J. de Lange

As a material asset for mining entities, the resources and reserves (RR) estimation processes are surprisingly underrepresented in the assurance landscape. When press reports expose them being inaccurately reported, or in merger and acquisitions processes, their importance becomes clear. The impact of erroneous RR numbers (both positive and negative) could have a material impact on an entity’s reputation and value.The technical nature and ‘black magic’ connotations of the RR estimation processes are possibly reasons why audit committees are not actively involved with it. Internal auditors avoid the RR processes for similar reasons. Also the traditional approach to obtain assurance on RR is expensive and is therefore only performed when it is absolutely required.However, stakeholders’ expectations of good governance are growing. Part of this increased focus is based on attaining a higher degree of certainty about the current and forecasted position of the entity. Stakeholders are also increasingly more interested in non-financial areas of entities, as the future success of an entity is more than a set of financial metrics.Consequently, the RR estimation processes should be visible on the agendas of audit committees. Monitoring of key controls is required as part of the governance obligations for senior management and the audit committee. So once it is on the audit committee’s agenda, the question then becomes, how will that agenda be supported by an assurance process that is cost-effective?The main objective of the paper is to describe a model of RR assurance that has been effectively applied in some mining companies. The paper discusses one particular approach that provides an audit committee with the required assurance regarding RR processes. The approach ties the assurance needs of the audit committee to the needs of the technical experts in the entity, therefore involving two important figures. It also offers assurance providers with a model to audit ‘through’ the RR processes rather than ‘around’ them. The paper then discusses top-down and bottom-up approaches that provide assurance at different levels of an entity.A governance audit that focuses on the RR processes is suggested as a top-down approach. A bottom-up approach assesses the design adequacy of internal control processes. A hybrid model is described which meets the needs of diverse stakeholders including the audit committee and the RR community.The hybrid model combines the expertise of professionals in both internal audit and RR. The right balance of these skills directed by a singular approach ensures that a credible result is achieved.This approach is not as expensive as some verification approaches used in the industry and can, as a result, be performed on a more regular basis.The last element of the paper looks at implementation of the reporting mechanism. An assurance process aimed at continuous improvement further enhances the robustness and reliability of RR reported by an entity.CITATION:de Lange, L J, 2016. Resources and reserve assurance processes – a framework for improved governance, in Proceedings International Mine Management Conference, pp 21-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By F. Charette

Instrumentation has been developed that can monitor the strain applied to a D-Bolt up to 7.5% elongation. The technology far exceeds the limit for foil resistance strain gauges. In the laboratory the instrumentation has provided insight into the fundamental behaviour of the D-Bolt following yield. Currently the instrumentation is undergoing field trials at a number of Canadian Mines. Discussion on field results is provided with regards to significance, reliability and temperature effects.

Aug 1, 2013

By John F. Papp

The objective of this U.S. Bureau of Mines study is to calculate an accurate, reliable estimate of chromium and nickel content of stainless and heat-resisting steel produced in the United States. The columbium, manganese, molybdenum, titanium, tungsten, and vanadium contents of this steel are also calculated. Such contents are required for estimating the quantity of alloying element recovered from recycled stainless steel and consumed by market sectors. In this investigation, the elemental fraction of stainless and heat-resisting steel was calculated as the ratio of the weight of element contained in stainless steel to the weight of stainless steel produced. The elemental fraction has been calculated as a time-averaged, grade-averaged value. The elemental fraction was averaged from 1962 through 1983, and averaged over the grades for which production was reported by the American Iron and Steel Institute during that time period. The 1962-83 average elemental fraction of U.S.-produced stainless and heat-resisting steel was calculated for chromium to be about 0.17 ± 0.01; columbium, 0.00014 ± 0.00003; manganese, 0.015 ± 0.005; molybdenum, 0.004 ± 0.001; nickel, 0.07 ± 0.01; silicon, 0.009 ± 0.001; titanium, 0.0004 ± 0.0001; tungsten, 0.0001±0.00003; and vanadium, 0.00003±0.0000l.

Jan 1, 1991

Greater mining productivity requires a more efficient cutting process. The cutting force available from today?s mining machines has been optimized with respect to machine size and weight. Researchers have shown that when employing water-jet-assisted cutting, bit forces and drum torques can be reduced significantly, which may allow mining machines to become lighter and more efficient. The Bureau of Mines has initiated a program to develop a water- jet-assisted rotary cutting system using the conventional bit assisted by a directed water jet operating at moderate pressures (3,000 to 10,000 psi). This water-jet-assisted cutting system has the potential to improve cutting efficiency without increasing machine horsepower or water usage (beyond what is presently used for dust control) or requiring fundamental changes in mining practice. IR addition to improvements in productivity, other anticipated benefits of water-jet cutting include reduced generation of respirable dust, elimination of frictional ignitions, increased bit life, reduced fines, and fewer machine vibrations. The papers presented at this open industry meeting discuss the development of water-jet-assisted cutting technology and future application of this technology to a variety of mining techniques including roof drilling and longwall mining.

Jan 1, 1985

By Harry R. Nicholls

As part of the pre- and post - shot mine examination at Project GNOME , acceleration data were recorded underground from a series of chemical explosive shots . The cube root of the charge weight was used to scale acceleration and distance because charge weight was not constant . Regression analysis of particle acceleration - distance data gave the following propagation equation : A W1 /3 = 5.10 x 105 ( R / W¹ / 3 ) −2 .43 The quantity A W1 /3 is scaled particle acceleration expressed in g's - lbs¹ / 3 , and R/W1 /3 is scaled distance expressed in ft / lbs¹ /3 Data obtained from the nuclear explosion were scaled and fall within one standard deviation of the calculated propagation law for the smaller shots . Cube root scaling laws were adequate to group acceleration data from explosive charges varying by a factor of more than 1 x 10 in charge weight and over shot - to - gage distances varying from 100 to 46,000 feet . Data obtained from a series of small tests provided sufficient data from which reliable predictions of acceleration could be made for the large nuclear explosion .

Jan 1, 1964

By Raphael Trousselle, William Reisz

The blasting industry is now well into its second decade of commercial use of electronic detonators. As an increasing number of blasters are introduced to the technology, the benefits are becoming more widely monitored and accepted in many surface blasting operations. However, their use in underground applications is not yet as widely established. This is primarily due to the distinct cost dynamics and processes associated with underground lasting.

Jan 1, 2012