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The last twenty years of development in Process Mineralogy are reviewed. Since the milestone review by Henley in 1983, which projected the concept and suggested closer working relations between mineral processing and mineral science, the second generation (1983-2003) has made significant progress. Examples are to be found in improved sampling and high-confidence flotation testing, and in automated quantitative mineral measurement. The recent addition of end-member studies has provided a clearer view of the overall ore mixture milled from its constituent geological components. In all, better predictive abilities have resulted from these improvements to Process Mineralogy. These improvements have led to more significant business impacts in mineral resource characterization, and in optimization of existing concentrator operations.

Jan 1, 2004

By Cheng Ang, Yun Bai, Zhi Liu

"This paper presents a conceptual design of an innovative tunnelling method named the Ring Pipe Jacking Method (RPJ) which is conducted by the Ring Pipe Jacking Machine (RPJM). The RPJM consists of a double ring shell which forms a ring section where small interlaced cutter heads or several micro tunnelling machines are assembled to cut soil. Similar to the conventional pipe jacking method, the RPJM also needs a thrust system, a slurry transport system, and a control system. To satisfy the need for large/super large or special section tunnels in future, the RPJM is designed to reduce sharply the excavation face to the annular section, thus enhancing the face stability. Part of the innovation is that the RPJM uses modular cutter heads or micro-TBMs which can be reused. The typical double shield shape can be easily changed by reinstalling the modular cutter heads. Modularity allows the tunnel to be cut in any cross-section shapes, ranging from a circular tunnel to a rectangular one. INTRODUCTION The demand and requirement to utilize urban underground space is rising with the rapid social development in recent years. It is necessary to reduce excavations of the urban ground surface to ensure smooth traffic in cities. Therefore the conventional open cut construction method for underground tunnels can no longer satisfy the need of practical engineering, and it is taken over by trenchless technologies .The Pipe jacking method is an important trenchless technology and is used more and more frequently to install underground pipelines, but the present pipe jacking method still has many problems. For example, it is not suitable for installing large-diameter tunnels and it also has difficulty in construction of short radius curved tunnels. This paper presents a conceptual design of an innovative pipe jacking machine named the Ring Pipe Jacking machine (RPJM) and introduces the correspondent Ring Pipe Jacking Method (RPJ) which can be applied to construct large-diameter tunnels. Furthermore, technical characteristics and superiority of the ring pipe jacking method are analyzed in this paper."

Jan 1, 2016

By J. Loredo

In some rural regions of Peru, artisanal gold mining is currently an essential activity as it provides an important source of income. In the Huanca region (Ayacucho Department) gold deposits are not attractive for mining companies due to their reduced size, but they have enough interest for artisanal mining because of the ease and low cost of mining operations. Artisanal gold mining represents an important damage for the environment, because operations related to amalgamation processes using Hg result in special environmental problems besides the typical ones commonly associated to all mining activities. A preliminary sampling has been made in soils, materials from tailing ponds and surface water of the Acarí River, at the site of the Huanca village, according to networks specially designed for the particular conditions of the area. Studies accomplished revealed high mercury concentrations in soils and tailings. Chemical analyses of soils directly collected in the area of the active or abandoned ?quimbaletes? show mercury concentrations ranging from 15.3 mg?kg-1 to 44.2 mg.kg-1. Mercury concentrations in soils decrease as a function of distance from the before mentioned sources. Water quality of the Acarí River that flows through the area does not present important changes as a consequence of the mining and processing operations.

Jan 1, 2006

By E. Lovera

Social attention to environmental aspects, steadily increasing in European Countries, has been leading to a stricter regulation of many productive activities. Among them, mining and quarrying sectors have been often censured for their potential and real impacts on land and environment. Referring to dimension stone exploitation (also the terms ornamental stone or natural stone are here used as synonymous), quarries are often concentrated in extractive basins, where the resource is localized with suitable quality and quantity: this fact has sometimes raised critical environmental situations. Nevertheless, dimension stone quarrying represents in Europe a traditional and important economical activity, source of wealth and employment. Moreover, many natural stones take on a ?cultural? value and may be considered as ?classic?, as they have been exploited since antiquity and are element of the architectural heritage of many Countries. The sector relevance demands the research of a sustainable balance between social-economical needs and environmental protection. Actually, very restrictive environmental protection policies have led to severe limitations to quarrying activity, but the results do not seem to be completely positive in terms of sustainability: on the one hand, closing-down stone quarrying activities imposes a shrinkage in local, social and economical development; on the other, quarrying activity is pushed towards developing Countries, environmentally un-protected, simply moving and putting off to next future the problem. The challenge of the sustainable development of quarrying sector ? recently explored in the European Commission?s communication ?Promoting sustainable development in the EU non energy extractive industry? (COM-2000-265) ? should be achieved through a positive link between theoretical statements and practical effects: sustainability indicators may be an effective instrument to assess and monitor the environmental performance of the industry. The paper refers to the development of specific ecological criteria and indicators, which can be useful to measure and predict the eco-efficiency of a dimension stone quarry, finally pointing out where improvement efforts have to be focused.

Jan 1, 2003

By K. Zhang

Real option value (ROV) method is considered to be more practical and advanced compared to net present value (NPV) method in evaluating a mining project, in particularly when there is substantial uncertainty in the commodity market as well as possible operational flexibility embedded in the project. Usually, it may take months or even years for the commodity product to be available in the market after the mining activation decision is made. The impacts of postponing the delivery of commodity product on the mine?s ROV and NPV are assessed based on the proposed real option method. Postponing the delivery of the products leads to declined NPV and ROV compared to the non-postponing scenario and extended postpone results in higher lost values in NPV and ROV. For a mine with lower mining cost, by postponing the delivery, the exercising threshold of commodity price is lower because the mine owner anticipates that commodity price may rise during the time of postponing. A mine with higher mining cost requires a higher exercising price threshold to ?lock up? the profit when there is ambiguity of market situation due to the postponing of the delivery.

Feb 23, 2014

By I. E. Zevgolis

A comprehensive critical review on the subject of sulfates-induced swelling behavior of lime-treated soils is presented in this study. Starting with the description of a well documented case study, the mechanisms behind the swelling behavior and the factors that affect this behavior are discussed. Then, the major experimental methods of sulfates content determination are briefly presented. Finally, an attempt is made to categorize sulfates level and equivalent risk for civil infrastructure. The paper indicates that limited work has been done, not only on identifying safe conditions for use of chemical stabilizers in presence of sulfate rich soils, but also on developing materials and methods to avoid, or at least mitigate, the problem.

Jan 1, 2008

By Ramon S. Pizarro, W. Joseph Schlitt

Introduction Trying to synthesize innovations occurring in gold processing is not simple. At present, this technology is exploding, brought about by the high price of gold. This price has compelled the mining industry, as a matter of survival, to produce gold. The frantic search for gold deposits continues, from glacial areas to tropical jungles. The search has been fruitful. New exploration techniques have helped to locate deposits. Some are amenable to conventional processing techniques. Others are in unusual settings that challenge the ingenuity of extractive metallurgists. Ore deposits containing traces of invisible gold, refractory mineralization, and impurities and deleterious materials that previously defied treatment are now being profitably processed. Metallurgists have developed various processing methods and equipment for gold ore treatment that reflect differences in ore characteristics, grade, mineralogy, reserves, topography, climate, and location. These processes can be categorized as: • For nonrefractory or readily leachable gold ores - vat leaching, heap leaching, and agitation leaching. • For ores containing free gold - gravity concentration methods, followed by mercury amalgamation, and • For refractory gold ores - flotation, roasting, pressure oxidation, followed by cyanidation leaching. In actual practice, a combination of these processes may be required. This is because gold mineralization, although usually simple, may be associated with other mineral species or with clays that make the ore difficult to treat. Furthermore, after the gold has been solubilized to form a cyanide complex, one of two important processes must be applied to recover the gold. These ore zinc cementation (Merrill-Crow process) and Carbon adsorption, desorption, and electrowinning. New techniques for leaching and recovery are also advancing. These will become the bases for the next generation of gold processing plants. Nonrefractory Gold Ores Nonrefractory ores with readily leachable gold are among the .easiest to treat. Even so, non-refractory ores from epithermal deposits are likely to contain too much clay. When these ores are damp, they may clog the screens and cone crushers. Depending on the type of process, scrubbing the crushed ore is very effective in overcoming clay problems. After dewatering, the slimes enter the cyanidation process and the thickener overflow is stripped of gold values and recycled. Semiautogenous (SAG) mills are also gaining popularity due to lower capital costs and ability to treat wet, sticky ores. If properly sized, the secondary crushing and screening plants, together with a secondary ball mill, can be eliminated. When the ore is of such a low grade that it can not support fine grinding, vat or heap 'teaching may be applicable. These systems are being actively applied in the US and elsewhere. Rapid construction and low capital costs are important features of these plants. Vat leaching is ideally suited for fast leaching ores and small tonnage deposits located in areas with harsh winters or wet tropical climates. For effective vat leaching, the ore is crushed to less than 25 mm (1 in.), agglomerated with lime or cement to control fines, and leached with sodium cyanide solution (upflow or downflow). The degree of size reduction is a tradeoff between increased costs of comminution and improved gold recovery from smaller particles. However, the size of material

Jan 11, 1984

By Lucy England

The following is a summary of the Robert E. Murray Innovation Lecture on “Sustainable Copper Mining Flowsheets and the MissionZero Mine” presented as part of the keynote session on Feb. 23, 2026 during the MINEXCHANGE 2026 SME Annual Conference & Expo in Salt Lake City, UT. As the world accelerates its transition to renewable energy, the appetite for critical minerals such as copper, lithium, nickel, rare earths and graphite has never been greater. Forecasts suggest that global mineral demand will double by 2050, driven by the proliferation of electric vehicles, renewable power infrastructure and digital technologies. This surge presents not only an immense opportunity but also an unprecedented challenge. In a world where every ton of ore processed and every liter of water used is scrutinized, how can mining deliver more with less, while meeting tightening environmental and social expectations? Traditional mining methods, developed for an era of abundant, high-grade ore and looser regulations, are struggling to meet today’s demands. Declining ore grades, volatile markets and the imperative to shrink environmental footprints have rendered traditional mineral processing practices unsustainable. The sector thus finds itself at a decisive juncture, caught between the need to fuel the green economy, defense and artificial intelligence (AI) infrastructure, without compromising the planet’s future. Balancing these competing demands requires a paradigm shift in technologies and processes. FLS has responded to this challenge with MissionZero: an ambitious, holistic initiative to develop flowsheets for the future of mineral processing. This systemic approach aligns operational excellence with environmental responsibility. Integrating innovative technologies, digital intelligence and commodityspecific process designs, it offers mining professionals a roadmap to meet both production targets and sustainability goals. At the center of this approach is the belief that a more sustainable mining requires more than incremental improvement; it demands a fundamental shift in how we extract, process and manage resources. By developing tailored flowsheets for copper, gold, lithium and tailings reprocessing, FLS aims to set a new standard for efficiency, circularity and environmental stewardship. The message is clear. We must achieve more with less: less energy, less water, less waste.

Mar 1, 2026

Exploration for SX-EW copper deposits and plant operation depend largely on the copper and gangue mineralogy inasmuch as? they govern the feasibility of leaching. Mineralogical parameters are pivotal in identifying if an ore is suitable to dump, heap, thin layer, vat or agitated leaching and/or if the ore requires curing, bioleaching or alternate lixiviants. Problems in metallurgical testing, production leaching and recovery forecasting are very often related to lack of mineralogical data. This presentation will illustrate the use of quantitative mineralogical analysis for exploration, acquisition assessment and optimization of copper leach operations.

Jan 1, 1996

By D. H. Garcia

The mining industry responded to public concerns about use of cyanide by developing a voluntary certification to allow companies to demonstrate their commitment. The International Cyanide Code (Code) establishes standards for the manufacture, transportation and use of cyanide. Key concepts in closure planning to comply with the Code are to decommission all facilities related to cyanide operations and to provide a financial assurance mechanism for those activities. Code requirements may differ from state-specific regulations, but requirements are based on closure goals for protection of the human health and the environment. Only issues related to cyanide operations are required to be included in decommissioning demonstrations. For example, the disposal method of cyanide solution holding tanks and the cost must be included in the closure plan, but information regarding closure of roads is not required. Closure costs must be based on a third-party contractor as opposed to internal budgets. Compliance with the closure requirements of the Code allows companies to show their stockholders, lending institutions, and the public that their operations are environmentally responsible.

Jan 1, 2010

By Louis W. Riggs

The primary concern in dealing with contractual arrangements for construction is getting the work completed satisfactorily, in the shortest time, and for the least expense for the owner--while assuring that all other parties associated with the contract make a reasonable profit for their effort. In our complex construction climate of today, achieving all of these is usually not possible. Somewhere between the beginning of design and the completion of the work, disagreements and delays arise which can destroy the best of intentions. Assuming that all parties associated with the contract are acting honorably and professionally, the disagreements generally arise through inappropriate contract types or through flawed contract documents. These flaws can be either sins of omission or commission, but we must find a way to lessen, if not completely eliminate, their impact. Disagreements and delays are directly related to the extra cost which the owner and the other involved parties must suffer. Usually the attorneys are the only ones who come out on the positive side. Inappropriate or defective contract documents can be the result of inadequate time for preparation and review, laziness in not searching out the proper terms and language, insufficient recognition of the proper assignment of risks, or just ignorance as to what is right and what is wrong for the particular project. They can also result from a client, particularly a public agency, providing rigid general conditions and format requirements with which the engineer is not allowed to tamper. Arguments

Jan 1, 1979

By Zoë Dugdale, Gerald Poplin, Tim Bauerle

"Fatigue presents several challenges for the mining industry. Depending on the specific occupation, daily work or operational setup on any given mine site, mining jobs can have a fair amount of labor-intensive tasks mixed with monotonous and repetitive duties. Combined with the long working hours and shift-work schedules of mining work, the prevalence of fatigue in mine workers may seem rather unsurprising.Mining is certainly not alone in facing the challenge of addressing worker fatigue. Indeed, many of the characteristics above mirror the similarities of fatigue in other industries, such as health care, aviation and security. To the extent that fatigue in mining acts like fatigue in any other industry, then any fatigue management applications, trainings, or interventions in existence can be borrowed from other industries and applied to mining in a cookie-cutter approach. However, some have argued that mining in particular is especially susceptible to increases in the prevalence of fatigue beyond the characteristics listed above due to the multifaceted combination of factors in mining environments associated with fatigue: dim lighting; limited visual acuity; hot temperatures; loud noise; highly repetitive, sustained, and monotonous tasks; shiftwork; long work hours; long commute times due to mine site remoteness; early morning awakenings; and generally poor sleep habits (Canadian Centre for Occupational Health and Safety, 2012; Legault, 2011). Legault (2011) in particular argues that it is the combination of these factors simultaneously that can make mineworkers particularly susceptible to sleep deprivation and fatigue in comparison to other industries where these factors are often not present all together. If fatigue looks and acts different in mining, as others have argued, more research is needed to determine if, how, and why worker fatigue might need to be managed differently in mining.While the burden of fatigue on the mining population has not yet been evaluated thoroughly, methods and measures of fatigue management remain a popular point of discussion. Many commercial suppliers and consultancy groups have begun to develop technologically based fatigue monitoring systems (McMillian, 2013). Some technologies can monitor vehicle operators for indicators of wakefulness, such as percent eyelid"

Jan 3, 2018

It doesn't take any special acumen to note that US engineering and construction firms are busier than ever with mining projects in this mineral conscious world. This special issue of Mining Engineering takes a look at E&C companies-their expanding role, their special capabilities, and their challenges and problems. ME sent a questionnaire to a representative sample of E&C firms. Information was sought about officers, ownership, and amount of business. ME also asked about types of projects and commodities dealt in as well as market distribution and forms of payment. The accomnanying charts show how the 17 responding E&C firms answered these and other questions. Other ME survey questions, and a review of company literature, yielded information about financing techniques and special challenges for E&C firms. Insights were gained concerning government impacts, customer-generated problems, and promising areas for development-including synfuels-in the minerals industry. These areas are discussed later in this article. Accompanying articles in the special issue discuss the E&C company's role in mining projects, research and development in E&C firms, one approach to contract work used by an E&C firm, and an E&C project case study.

Jan 10, 1980

And a new generation of safety culture experts are telling mining companies how to use it: It is a situation that is still too common in the mining industry: the latest personal protective gear is in place. The safety rules are known and followed. And then, in a moment of inattention or carelessness, a mistake is made and someone gets hurt or killed. Common wisdom claims that such accidents are impossible to eliminate entirely. Mining is dangerous, and some miners will always be hurt and killed. An increasing number of mine safety experts, however, reject the common wisdom. A year with zero mining deaths is possible, they say; with the use of one of the newest weapons to the mining industry in the safety war: the concept of safety culture. Safety culture refers to the set of attitudes, beliefs, perceptions and values that influence safety in the work environment. It is also sometimes called the way an organization behaves when no one is watching. Robert Peters, of the Office of Mine Safety and Health Research (OMSHR) at the National Institute for Occupational Safety and Health (NIOSH), describes safety culture this way: ?It?s what?s believed on a day-to-day basis. For example, if a miner sees a workplace hazard and he truly believes that his boss wants him to identify the hazard and bring it to the company?s attention, that would be an example of a positive safety culture.?

Jun 1, 2010

By T. Zoltai

Asbestos is a generic term for industrially useful fibers recovered from exploitable deposits of the asbestiform varieties of five silicate minerals: chrysotile, anthophyl-lite, actinolite-tremolite, cummingtorute-grunerite, and rie-beekite. Asbestos and asbestiform fibers of some other minerals are known to be carcinogenic. Minerals crystallized in the asbestiform habit-are characterized by unique properties (morphology, strength and flexibility, physical and chemical durability, and defect-free surface structures). The key to the unusual properties, and health effects, of asbestiform fibers appears to be in their unusual surface structure. In contrast, non-asbestiform crystals of the same minerals, including the five so called asbestos minerals, do not have these properties and are not carcinogenic.

Jan 1, 1989

By M. S. Seehra, V. Suresh Babu, R. S. Pandurangi

Different mixtures of the three polymorphs of silica viz. quartz, cristobalite and tridymite are analyzed by x-ray diffraction (XRD) and their IR spectra are investigated by photoacoustic spectroscopy. It is observed that XRD provides a higher resolution to distinguish between the three polymorphs in a sample than IR spectroscopy. In the latter, a sharp band near 617 cm-1 is characteristic of both cristobalite and tridymite. A mine dust sample is quantitatively analyzed by XRD and it is shown to contain illite, quartz, kaolinite and calcite.

Jan 1, 1991

By Dan Brunner, Scott Thomson, Ben Lyddall, Duncan Thomson

Geosensing is used in oilfield drilling in conjunction with geophysical tools to support characterization of rock properties, geology, and reservoir conditions. This technology is now available to the mining industry and has been successfully applied to underground in-seam directional drilling in Australian coal mines for geologic exploration and methane drainage. The system utilizes a range of drill rig and wellhead mounted sensors which, combined with analytical software, produce real-time data from which 3D spatial features can be accurately modelled significantly in advance of mining. This innovation greatly expands on the information obtained from current in-seam directional drilling practices and provides for improved characterization of coal seams, including soft and weak zones, locations of geologic discontinuities, and analysis of formation flow. This paper provides a description of the geosensing system and the interpretation of actual data from long in-seam directionally drilled methane drainage boreholes at mines in Australia, and discusses how this system increases the value of directional drilling as an exploration tool for the coal mining sector, and the evaporite and hard-rock mining sectors where directional drilling is also applied.

Feb 1, 2024

By J. Duncan Wilkins

Introduction In difficult times such as these, there is a strong reaction to the current way of doing things. Typical reactions that we have all heard are "There has to be a better way," "We're pricing ourselves out of business," "We have to improve our productivity," and "We have to have more cooperation," between union and management and employees and management. All of these comments have at their roots one common factor - getting the maximum amount for your dollar. The other factor inherent in these statements is productivity. I have not yet met a person in our industry who has not expressed the opinion that we should, and that we can, improve our productivity. Reducing Labor Costs In light of these factors I suspect we have all spent a fair amount of time examining our labor costs. For some of us, labor costs are a high proportion of our total cost of doing business. To alleviate the impact of these costs, we have generally done four things. We have reduced our number of employees, shut down operations for appropriate periods, sought concessions from union employees, and placed freezes on wages, salaries, and other benefits on nonunion employees. These approaches have been made to improve current shortfalls in our cash positions - to tide us over, as it were - or to provide us with a chance for survival. These are short-term measures that help to bring immediate relief, but can pose significant problems (or challenges), for the longer term. For instance, what do we do when times improve? How much do things have to improve before we do anything? By seeking concessions from unions in bad times, what do we do when unions come to us in good times? It is a rather sad and critical fact that we have grown too fat during the good times and too thin during the bad. In the first case, we have failed to optimize our earnings. In the second, we have cut ourselves too far. Consequently, when good or better times have arrived, we have had to bulk up our requirements to meet production commitments. In mining, for example, when times become tough, we tend to reduce our development plans so that when times improve we have to really "sock it to 'em," so that we can maintain productive capacities. We should plan ahead a little more to reduce the amplitude of our cyclical wavelength, so that in good times profits are optimized and in bad time we are better able to take the strain. Of course, forecasting cycles is not a refined art, but if we properly control our work force levels and costs at all times, and therefore optimize our productivity, we would be more able to withstand the problems we face today. Unfortunately, it appears that it takes bad times to bring us to a realistic appraisal of our way of managing our businesses. Labor Practices Not all of the problems now faced are due to low metal prices. Inflation has played a major role in bringing costs to a frightening level. Trade unions alone can not be blamed for high inflation levels over the past several years, popular though that notion is. Contract negotiations, after all, require two parties. Indeed, our current levels of labor cost are due to two factors: • We have felt obliged to keep our employees whole, relative to the cost of living. • We have felt obliged to maintain our competitive position relative to our peers, in order to maintain our ability to attract and retain a skilled, efficient work force. In the first case, our felt obligation has been applied without due recognition of the factor of performance, either in individuals or groups. Average, even mediocre performers, have been amply rewarded for their average work and mediocrity, while the good performers, no doubt receiving more for their good work and effort, have not perhaps appreciated the slight premium for their effectiveness. The rather predictable result of this practice has been that the average and mediocre stay that way (why change?), while some (certainly not all) of the good performers have said "It's not worth it," and slipped into the warm, cosy pool of the average and mediocre. In the second case, that of maintaining competitiveness with other companies' employees, we have compounded an already serious problem of lack of skilled tradesmen by paying higher and higher prices for the existing pool to maintain comparability without improving the flow of more skilled people through sound and sufficient training programs. We have the rather dubious pleasure of paying more and more for the same problems. Compensation is either mutually agreed, as with unions, or it is unilaterally applied, as with nonunion employees. Generally, there is more flexibility available to the employer when dealing with nonunionized groups than there is with unionized groups. Sometimes that flexibility has not been used well, most often be-

Jan 11, 1983

By Ryan Ward

The Missouri River Intake Screen Structure and Tunnel (MRISST) is one phase of the Red River Valley Water Supply Project (RRVWSP), a vital piece of infrastructure in the state of North Dakota to transport water to drought-laden communities in the eastern half of the state. The scope of work consists of constructing a cofferdam in the Missouri River, mining a 1,600-foot by 74-inch tunnel from a secant pile shaft near the riverbank into a cofferdam, and erecting a 40-foot Y-shaped vertical pipe structure in the cofferdam to support the intake screens. Construction personnel worked in the river through the North Dakota winter to construct the cofferdam and contended with high hydrostatic pressures and raveling sands, gravels, cobbles and boulders while mining the tunnel. Diligent planning and meticulous execution were essential to overcoming the challenges encountered below the Missouri River.

Jun 13, 2023

In order to analyze and quantify distinct environmental properties in the vicinity of sites, the Site-Specific Natural Resources Information System (SARIS) has been developed based on a Geographic Information System (GIS). SARIS is one of the fundamental databases of a collaborative research program aiming at the resource orientated analysis of metallic raw material flows with aluminum and copper serving as exemplary case studies. The spatial database incorporates all present production sites of ore extraction, refining and smelting. Environmental data for each location were derived from global digital survey data covering land cover, soils, morphology, climate, topography and population density. The main application of this database is the characterization of environmental safeguard objects, which may be affected by the activity of concern. This site-specific environmental impact assessment is used to determine the relevance of environmental issues based on the distribution pattern of sites in a global framework. The derived results are used to suggest a tailored indicator approach to measure progress and performance of industrial developments relative to the predetermined site-specific conditions.

Jan 1, 2003