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By Sushant Upadhyaya, Deniz Karadeniz

As part of the widening of I-64 in Williamsburg, Virginia, an extensive subsurface exploration program consisting of Standard Penetration Tests (SPT), Cone Penetration Tests (CPT), Dilatometer Tests (DMT), and Vane Shear Test was performed. In addition to these in-situ tests, an extensive laboratory testing program was completed including Consolidated-Undrained Triaxial, Unconsolidated-Undrained Triaxial, Direct Shear, and consolidation tests. The strength and the compressibility properties are deemed conservative for Yorktown and St. Mary’s Formations when evaluated based on the current topography, the existing overburden pressure and SPT values. SPT exhibited low blow counts especially within Yorktown Formation due to the increased excess pore water pressures resulting in a localized liquefaction at the tip of the split spoon sampler corresponding to remolded or fully softened strength of the soil. Therefore, the applicability of the SPT correlated soil parameters somewhat leads to conservative designs with deeper piles to achieve a desired structural load demand. Generally, the in-situ estimated soil design parameters are found to be comparable with the laboratory test results corresponding to long-term resistance gain with time. It is of practical importance to employ realistic soil design parameters for design applications such as pile foundations to provide cost and schedule savings. This paper presents a discussion on the soil strength estimates and variability from in-situ and laboratory tests for realistic strength characterization of Coastal Plain deposits.

By N. Mutemeri, T. -L. Field, M. Chuma

The categorization of artisanal and small-scale mining has a significant impact on perception and understanding of the sector, particularly from a livelihood perspective. Several developing countries classify different types of artisanal and small-scale mining based on legal status. Given the nature such activities, the tragedy of the commons theory has been applied to understand the inevitable environmental, economic, sociocultural, safety, and health negative externalities – which are products of informality and illegality. Consequently, formalization is a panacea to sustainability. This article aims to offer a conceptual organization and foundational knowledge for characterization of artisanal and small-scale mining. It seeks to identify existing literature on the subject to avoid replication and acknowledge other scholars. Moreover, the article aims to place the study within the context of existing literature, establishing relationships with other studies and why the research is necessary. This paper pinpoints gaps left from other studies in so far as the characterization of artisanal and small-scale mining is concerned. Thus, reviewing literature abetted in finding similarities and differences on how artisanal and small-scale mining is defined from a scholarly and legal basis. The paper ascertains major claims made by earlier research on this topic, such as environmental impacts, the lack of adequate regulatory framework, and presents querying and probing questions lacking from other studies.

Jul 10, 2024

By P Hatherly, A Melkumyan, D Wyman

Chemical species distributions in rock sequences can be modelled using Gaussian processes (GPs) to predict the weight percentage between known data points. This method can be improved by dividing the modelled area into regions of different mineralogy. In the context of many iron ore deposits, marker shales give the initial guidance of where these regions may lie. These shales give rise to distinctive peaks in the natural gamma downhole logs, which are conventionally identified by hand. A GP method has been developed to automate this task.Once the appropriate boundary has been located on the basis of shale occurrences, chemical assays from exploration drill holes are used to find the exact boundaries of interest. These boundaries divide the drill hole stratigraphy into regions of different mineralogy, each of which display their own distinct correlations between the main elements and oxides (Fe, SiO2 and Al2O3). Iron ore shows a negative correlation between Fe and Al2O3, but in banded iron formation (BIF) there is a positive correlation between these species. Similarly, SiO2 and Al2O3 have a positive correlation in the shales and ore but a negative correlation in the BIF. Correlations obtained within ore-, BIF- and shale-dominated regions are therefore better than those obtained using the entire log and can be used to improve the results obtained when modelling.

Sep 26, 2011

By Y Peng, C Burns, Y Mu, R A. Lauten

In both laboratory flotation experiments and from analysing the composition of the lead concentrate at the Boliden Tara lead-zinc mine in Ireland, it has been found that F-250 may replace cyanide as a pyrite depressant. Replacement or reduction of the cyanide consumption is highly desirable from a safety perspective given the toxicity of cyanide. Scrutiny of results from the plant trial indicate that F-250 is less efficient as a cyanide depressant when the flotation feed contains high levels of pyrite. Statistical analysis of the results does not capture this trend, illustrating a need to collect more data at higher pyrite ore levels. A recent model proposed for biopolymer-induced pyrite depression is reviewed and discussed next to the suggested mechanism for pyrite depression via cyanide. Review of the interactions causing pyrite depression point to different manners in achieving depression. In light of the less efficient F-250 pyrite depression at high pyrite levels, it is speculated if the two depressants may act synergistically at high levels of pyrite in the feed. CITATION:Lauten, R A, Burns, C, Mu, Y and Peng, Y, 2018. Pyrite depression at Boliden Tara using F-250 – a biopolymer, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By R M. Smart, A T. Harrison

Backfill systems using unconventional cementitious binders have been successfully used in relatively deep and hard rock tabular mines for longwall, scattered stoping and shaft pillar removals. Two unconventional cementitious systems are discussed: A ground granulated blast furnace slag (GGBS) with an activator containing lime. This has been used with a total tailings æstableÆ slurry at a relatively low dosage of less than seven per cent, by mass, based on dry solids. The room and pillar stopes supported with this fill were up to 20 m high and the tailings were relatively high in pyrite. A GGBS binder plus a silicate based activator and gelling agent that virtually eliminated all water drainage (and hence post filling shrinkage). The system used a slurry, but the addition of the activator created a final placed product that had the behaviour of a paste. The system has been successfully used for almost ten years in the following applications: stoping widths (mining heights) above 1.6 m; and shaft pillar removals in seismically active areas at the end of the life of the shafts. This paper discusses the technical merits and costs of the systems and compares them to other fill systems (including true paste systems). the acceleration (normally g, 9.81m/sec2) is increased to a significantly larger (but generally unmeasured and unknown) value, as shown in Figure 1.

Jan 1, 1998

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By Jamal Rostami, Mark Board, Clayr Alexander, Muthu Vinayak Thyagarajan

In the past several decades, many major equipment manufacturers have ventured into developing new technology for underground hard rock excavation. This includes variety of configurations for full and partial face mobile excavation units. Mining industry prefers machines that can excavate noncircular, flat invert profiles and be able to make tight turns in hard rock. The need to use disc cutters for cutting hard rock has impeded the development of such machines due to the need for gripper system or large mass of a machine to support the force requirements of the disc cutters. Most of the prior attempts have been partially successful and the operations have faced some practical limits and challenges. Among the units that have been successfully used, one can name mobile miner, which was used for rock excavation in some projects. A redesigned mobile miner, called the “Remote Vein Miner,” or RVM, has been developed by Epiroc for underground hard rock mining in Hecla’s Lucky Friday Mine. This equipment potentially opens numerous opportunities for innovation in civil tunneling projects, where the operational flexibility and accessibility of a TBM’s limited tunnel path, design of the profile, and cost are limiting factors. This paper explores the application of the RVM in tunneling projects, its advantages and possible areas of innovation in tunnel planning and design.

Jun 13, 2021

By Ananda Moreira Vaz Ourique de Avila

High and intermediate temperature fuel cells (FC) are power generators characterized by high efficiency and their use in cogeneration systems. The single fuel cells are connected in series by the use of interconnects to form a fuel cell stack. Ferritic stainless steels have been used in the making of high and intermediate temperature operation solid oxide fuel cells interconnects. However, at high temperatures, on the order of 700-8500C, these steels can present significant oxidation and degradation processes, promoting increased electrical resistivity and corrosion losses that result in contamination of the electrodes and reducing the performance and the useful life of the FC. Intensive R&D activities have been made to minimize these problems and the use of composite coatings on metallic substrate has been considered. This paper evaluates the use of coatings of copper and nickel, with particles of La2O3, Y2O3, CeO2, LaCrO3 and doped chromites applied on ferritic stainless steels AISI 430, AISI 441 and Crofer22APU produced by electrodeposition. The produced samples were evaluated by microscopy techniques, gravimetric analysis and by electrothermal characterization. The most significant results were obtained with chromites coatings (LaCrO3 pure, mono- and multiple-doped) showing the combination of the best features of metal coatings, substrates and ceramic particles with semiconductor properties.

Aug 7, 2018

By B Dold

Western Europe is a dynamic region, with an emerging co-operation between the individual nations both politically, economically, technically and scientifically. The European Union, today with 15 member States and with a range of central European States applying for membership, is a catalyst for this Cupertino, using a combination of EU funds, for financing research initiatives, and legislation to enhance development of technology and environmental performance. Europe is a major net importer of metals but with a large potential for own production, in particular in the accession countries. The metals and mining sector is furthermore identified as having a large potential to generate wealth both in todayÆs EU and in the future, widened Union. This paper provides a chart of examples on the many research initiatives presently underway in Europe, addressing environmental issues related to mining. The list of programmes and projects does not claim to be complete; it is rather an illustration on the wideness of the approach, describing various ways for transboundary Cupertino. The approach taken by many of the programmes goes beyond the strict ARD scientific area and therefore only a limited number of the many programmes can be identified as ARD research programmes. Also national programmes, without EU funding, are operating, eg in Sweden, Germany, and UK. The picture is continuously changing with new programmes being commissioned and old ones being completed.

Jan 1, 2003

By R. R. Rogers

ABSTRACT The experiments described demonstrate that crude commercial lithium containing in the order of 0.5 per cent sodium can be refined, the resulting metal containing as low as 0.001 per cent sodium. During the process, the metal is vaporized and condensed at a gauge pressure of less than 0.04 micron. Considerable operating data and a detailed description of the experimental equipment are included. INTRODUCTION DUE TO THE unusual properties of lithium metal, its use is likely to increase considerably during the next few years (1, 2). This is of particular interest to Canadians because there are important deposits of lithium-containing minerals, especially spodumene, in Canada and it is hoped that lithium compounds and lithium metal will be produced from these deposits in the fairly near future. In order to assist in the development of this industry, the Mines Branch of the Department of Mines and Technical Surveys has initiated a programme of research in lithium metallurgy. In 1948, a paper (4) was published on methods of producing lithium metal and its alloys. Data on the corrosion resistance of some lithium alloys were included. In 1949, a paper (3) was published which showed that the addition of a small percentage of lithium to zinc anodes used for cathodic protection will improve their usefulness under certain circumstances.

Jan 1, 1951

By J. K. Pothal, S. Basu, R. Barik, P. K. Senapati, A. Dubey

The aim of this paper is to study the characteristics of limestone particles (size varies from 4 mm to 20 mm) during its transportation from open cast mines through pipes. The influence of four different size fractions of limestone samples (4–6 mm, 6–10 mm, 10–15 mm, and 15–20 mm) on pipe flow characteristics during vertical transport in a 100 mm NB hose pipe was investigated. The flow velocities in the vertically lifting pipe was varied from 0.95 m/s to 2.78 m/s and a rotary feeder of 2 to 4 tonne/hr. capacity was employed to feed the limestone samples to the lifting pipe. The pressure drop data for the different size fractions of limestone samples at different mixture velocities were analysed. The effect of input volume fraction and superficial velocity of limestone samples on hold-up ratio were discussed. It was indicated that there was no substantial increase in pressure drop of slurry samples in the studied range of concentrations (CW = 4.22% - 12.54%), particle size, and low to medium range mixture velocities with respect to water run head loss data. The hold-up for the larger size fractions (15–20 mm) of limestone samples was found to be significant as compared to smaller size fractions, which may be due to terminal settling velocities of individual fractions of the studied samples.

Mar 4, 2025

By G. F. Friel, J. C. Edwards

A series of seven underground-coal-mine fire experiments was conducted in the Safety Re-search Coal Mine at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory. Coal and styrene-butadiene-rubber conveyor belting were burned upwind of two sensor stations, 18 m and 148 m from the fire source. Exhaust from a diesel locomotive flowed over the fire sources in six of the tests. Metal-oxide-semiconductor (MOS), CO, and optical-path-smoke sensors were positioned at both stations and found to be an optimum set of sensors for the fire discriminations. A representative set of 7,679 samples of CO data and data from the smoke and diesel-exhaust MOS sensors were used as inputs to train a neural network (NN). By testing 42,538 data samples from the seven experiments, all fires were detected by the NN within 9.67 min from the onset of significant changes in the MOS voltages without any false alarms.

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

By U. S. Geological Survey

In 2025, the estimated total value of nonfuel mineral production in the United States was $112 billion compared with $106 billion in 2024. The estimated value of metal production in 2025 increased by 13 percent to $38.1 billion from a revised total of $33.6 billion in 2024. The total estimated value of industrial minerals production was $73.7 billion, 2 percent more than the revised total of $72.2 billion in 2024 (Table 1). Increases in production of certain nonfuel mineral commodities, along with increases in prices of some industrial minerals contributed to the overall increase in the total value of domestic nonfuel mineral production in 2025. For the industrial minerals sector, the production value of natural aggregates, which comprised approximately 60 percent of the total production value of all industrial minerals, increased by 4 percent even though production volumes decreased by 1 percent in 2025 compared with production in 2024. The largest percentage increases in production value in 2025, in descending order, were for dimension stone, wollastonite, potash, mica and portland cement. The largest percentage decreases, in ascending order, were for high-purity quartz, industrial sand and gravel, lithium carbonate, bromine and boron. For the metal sector, production decreased for several mineral commodities and prices decreased for several metals due to oversupply. Lithium, manganese and nickel had some of the largest percentage decreases in production value.

May 1, 2026

By Stephen Se

Geological assessment of active mine faces enables ore grade control, geological modelling and exploration planning. Monitoring of the mine advancement at every drill-blast-muck cycle allows for effective production management. However, geological assessments are performed infrequently due to the need to travel to active mine faces, and detailed surveys to map the mine progress are performed at the end of the month. Instant Mine Modeller (iMM) is a portable ruggedized stereo-vision system that creates photo-realistic three-dimensional models of underground mine faces on-site. The 3D models are generated automatically within minutes and can be viewed underground and annotated with geological information. The overall ore percentages of the face are calculated automatically for grade control. Annotated 3D models are located in the mine coordinate system and can be imported into mine management systems. iMM allows for daily monitoring of the mine progress and geology, and for re-visiting the mine virtually as it existed. iMM has been deployed in an underground hard rock mine for 18 months, and it effectively brings the underground work face into mine management offices enabling the right decisions at the right time. iMM has demonstrated benefits to various mine processes including grade control, geological mapping, 3D photo-realistic as-built and production volume.

Oct 1, 2009

By K. E. Harrison

The acid rain legislation has passed into law. This new law has caused the power generation community to investigate alternative methods to obtain compliance with the new legislation. One thing all of the power companies have concluded is the answer is not easy. Do we switch fuels to burn all low sulfur compliance coal? Maybe possibly only partial desulfurization by means of a dry sorbent system? Or, finally, maybe a wet scrubber system? Whatever the choice, the power community needs to investigate all of the alternatives. In 1988, ICF Kaiser Engineers, Inc. (ICF KE) responded to a request by the U.S. Department of Energy for the engineering development of advanced physical fine coal cleaning. ICF KE responded and was awarded a contract to conduct a multi-task program to develop an advanced flotation system to eliminate pyritic sulfur and retain as much energy as possible. ICF KE assembled a team that included members of industry, academia, and industry research organizations to conduct this multi-task program. The program includes sixteen (16) tasks. This team had personnel to help solve some of the anticipated problems and to provide industry prospective on the viability and commercial potential for any concepts proposed. The primary team consists of a major coal producer, Babcock and Wilcox, Eimco Process Equipment Company, and Virginia Polytechnic Institute and State University.

Jan 1, 1992

By Amri Priambodo, Ian Leslie, Valérie Laflèche, Agustina Ratnaningrum, Robin Paine, Andrianus Sinaga, Willem de Beer

Freeport Indonesia consists of surface, civil and underground mining areas exposed to numerous geotechnical risks and hazards. PTFI uses various monitoring systems (Micro-Seismic, Firefly Light System, Mira Geoscience machine learning, etc.) to effectively manage these risks. The significant volumes of data from these sensors must be integrated into actionable information to provide the expected risk management. This occurs at the GeoEngineering Integrated Monitoring Centre (GIMC), a centralized department within the GeoEngineering Division, tasked with the responsibility to manage all geotechnical monitoring systems. The main hazard the GIMC is responsible for managing in real time is mine seismicity within the underground mining areas and the potential impacts on safe operations. Seismic system engineers achieve this objective through 24 hours a day and seven days a week operations of the GIMC, providing a centralized point of communication, alerts, evacuations and control during seismic events and emergencies. This paper will describe how the GIMC achieves its goal using reliable procedures and strategies based on detailed Triggered Action Response Plan (TARP), concise communications, novel technologies (FireFly Lighting System), and proven seismic re-entry programs to manage risk within the underground mining operations. The integration of geotechnical monitoring and reporting into a centralized group has improved the effectiveness and management of seismic risks and hazards at PT Freeport Indonesia (PTFI) mining operations.

Apr 26, 2022

By Frank T. Sisco

SHORTAGES of metals and minerals and substitution of less critical materials for those in which a virtual famine exists received detailed and frank discussion at a recent conference in Washington called by Robert E. McConnell, director of the Conservation Section, Office of Production Management. Representatives of the large engineering societies in the United States and O.P.M. department heads participated in the discussion. To open the session Mr. McConnell called upon Zay Jeffries, chairman of the O.P.M. Advisory Committee on Metal Conservation and Substitution, to summarize the present situation. Dr. Jeffries touched briefly on the status of metal shortages, which has already received considerable attention in the popular press, and said that much of the present difficulty was caused by the too-hasty substitution-without sufficient con¬sideration of the immediate conse¬quences-of metals having ordinarily a small yearly consumption, for those having a much larger annual consumption. As a result, all the alloying metals used in alloy-steel manufacture have become scarce, with the exception of molybdenum; further¬more, despite a reserve of 11,000 tons of molybdenum in this country and despite a normal consumption of only about 3500 tons and a prospective annual production rate of 21,000 tons by October, a shortage of molybdenum is possible before this war is over.

Jan 1, 1941

By E. O. Jacobs

A coupled solid and rock fracture mechanics model is used to analyze the blast driven fracture propagation phase, predict propagation rates, and directly measure shockwave and particle velocity. The study incorporates quasi-static pre-stress conditions for different depths below the surface. The scaled experiments include dynamic material properties and quasi-dynamic fracture mechanics which are shown to significantly affect the fracture propagation. The study was performed using three-dimensional cube-type laboratory models fabricated from Polymethylmethacrylate (PMMA). The test cubes are loaded with explosives and resulting fracture networks are studied. The dynamic evaluation of the spatial crack system is monitored using a high speed image camera. An experimental model set-up is designed to indicate the pre-stress effect on deep borehole blasting and is shown that the pre-stress conditions have a decisive influence on fracture profiles and orientation. It is found that shockwaves rapidly exceed the slower dynamic fractures and a majority of cracks occur due to detonation pressure. Experimental testing using different parameters validate that explosive fracturing can predict the outcome of fracture and crack propagation in any rock type with known material properties. This can be accomplished under great stress conditions deep below ground surface. The experimental study results can be applied to a variety of industries such as mining and quarrying, tunneling, oil and gas, and construction.

Feb 23, 2014

By Terzis D. PhD, Katterbach M.

While awareness around the environmental impact of existing grout materials and chemical binders is increasing rapidly, biotechnologies are growing traction as sustainable alternatives in groundwork operations. Herein we present the principles and application methods of bio-grouting. The term is used to describe a system which is based on soil, groundwater or marine enzymes which are able to catalyze the production of calcite replicating a natural phenomenon. The system’s end result are mineral crystalline bridges which act as binders to improve the geotechnical properties of soils. This paper presents a comprehensive description of bio-grouts, their underlaying mechanisms contributing to mineralization as well as environmental considerations. With their water-like rheology, bio-grouts have a wide application range and are minimally invasive, requiring only very limited injection pressures. The equipment is the same as that used in conventional cement grouting, and the reactant components are worldwide available or easily suppliable, which explains why bio-grouting has nowadays become a valuable and sustainable alternative towards efficient soil treatment. Recent developments in the last years have allowed to further increase the applicability and efficiency of bio-grouts to ultimately bridge the gap between research and practice. A case study is illustrated in this paper showing the successful implementation of bio-grout for the stabilization of weakly cemented sandstone to safeguard an adjacent road segment in Switzerland

May 1, 2022