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By Simon D. Strauss

The recession that began in late 1980 has proved to be not only prolonged and severe, but in certain ways unique in its effect on the mineral industries among the periods of economic slowdown experienced in the Western world since the end of World War II. This time almost all minerals have been affected. In previous business turndowns, by contrast, some mineral sectors have with-stood economic adversity well. They experienced little or no adverse effect-thanks either to a strong secular expansion in the markets for their particular product or to specific factors that caused demand to be well maintained. For example, aluminum, molybdenum, and nickel are three metals that enjoyed extraordinary growth in applications during the years 1946-1973. These metals were little affected during the recessions that occurred in that era. Similarly, coal did not suffer a pronounced drop in sales in the 1974-75 turndown because, with the price of oil rising sharply, a switch away from oil and back to coal was clearly indicated for some energy-intensive applications. Oil itself was largely impervious to the ups and downs of the business cycle until very recently. And the precious metals, gold and silver, have often been regarded as benefiting from reduced economic activity because labor becomes more available, productivity rises, and operating costs diminish. In the current recession, however, no major mineral has escaped the broad trend. The secular growth factors that were previously so evident for aluminum, molybdenum, and nickel have disappeared, at least temporarily. The stable pricing behavior that previously characterized all three of these commodities has been replaced by extreme price weakness and apparent inability of the major producers to continue their roles as market leaders. Coal and oil both have suffered from a sharp drop in energy requirements. There are those who now anticipate a collapse of the market control over oil prices so clearly exercised by OPEC since 1973. If oil prices are no longer effectively controlled by the governments of the exporting countries, then coal prices are also certain to be affected. And the combination of high interest rates, tight money, and a change in public perceptions of precious metals put the skid under gold and silver quotations in 1981 and early 1982. Although inflation has been viewed as the scourge of most Western countries ever since the oil crises of 1973-74, prices-in constant dollars-of most minerals have not risen. On the contrary, with the exception of the precious metals and oil, for most minerals the prices that prevailed at the end of 1982 were close to the levels of the Great Depression of the 1930s in constant dollar terms. Table 1 compares prices for copper, lead, zinc, and aluminum at the end of 1982 with the average prices in 1934, stated in constant 1967 dollars. This emphasis on prices for mineral commodities reflects the fact that profits of mining enterprises vary directly with the level of prices. Manufacturing and retailing enterprises march to a different tune. They establish sales prices based on costs. Their profits tend to vary with volume. Commodities are for all practical purposes fungible, that is the advantages of known brands in marketing manufactured goods have little application in a commodity market. Thus the individual seller of minerals is unable to establish his sales prices. Except where a monopoly is present, he must sell at the going market. His option is to abstain from selling if he finds the price unremunerative. In past recessions, some mineral producers chose to do precisely that-either accumulating a substantial share of their output in inventory or, in prolonged downturns, abstaining from production. During the current recession, however, private-sector mining companies did not have the option of accumulating inventories to any great extent. Capital costs for new mineral projects or for expansion of existing facilities have escalated at an alarming rate since the early 1970s. Added to this has been the heavy cost of installing pollution control or safety equipment to comply with the regulations adopted in most industrialized countries (and particularly the United States) since 1968. The consequence has been that the financial position of most major mineral enterprises in mid-1980 was already strained. To finance increased inventories meant incurring additional funded debt at high interest costs, thus impairing the concern's credit rating. Management Choices Private-sector managements have had to face up to the alternative of either continuing to produce at an unchanged rate and marketing output at unremunerative prices or reducing output. The latter has meant either operating at a curtailed rate, with con-

Jan 3, 1983

By Terrence Chatwin, Michael Sweeney, Steve Accardo

Sutter Gold Venture excavated an exploration decline into a mineralized zone in the Sutter Creek gold mining district. Delays in obtaining the conditional-use permit resulted in 7 to 10 million gallons of water accumulation in the decline containing elevated dissolved arsenic. Sutter received a permit to land apply the water after reducing the arsenic concentration to 0.05 mg/L. Initially the water was treated by co- precipitation arsenic with ferric hydroxide. Operational difficulties of this treatment system resulted in Sutter pursuing alternative treatment methods. The activated alumina adsorpting was selected due to its flexibility and ease of operation. Operating and maintenance data and costs will be presented.

Jan 1, 1995

By Samuel W. Woods

The Tacoma, Washington plant is one of six plants in the United States Gypsum Company's Acoustical and Mineral Fiber Division. The Tacoma facility was acquired in 1959 along with six other mineral wool plants from the American Rock Wool Company. Originally, the Tacoma plant was built as a carbide plant during the Second World War and after that was converted and operated as a mineral wool plant by several insulation companies. Through these early years, the use of raw materials at Tacoma consisted primarily of slags along with small percentages and various combinations of silica (in various forms such as gravel), limestone and basalt. These raw materials were melted in cupolas using coke as the heat source. Raw material usage and types as well as mineral wool production methods and equipment remained without major changes for many years.

Jan 1, 1983

By Jeff Easton, J Johnson, D. Foot

The Mina Santa Rosa mine in Panama was the victim of a mine closure 24 years ago that left the community in dire straits. The mine showed the potential resources of greater than 1M ounces of gold and 4.5M ounces of silver. Veragold Mining Company decided to reopen the mine and address all the issues that were involved in the startup of an historic mine. This paper provides methods to restore the community trust, provide a transparent process, and develop an environmentally sound flowsheet. Immense scrutiny surrounded the Tailings Storage Facility, and the company developed a plan focused on paste thickening and surface stacking to eliminate the need for a conventional tailings’ facility. Paste thickener principles and benefits are also provided.

Feb 1, 2024

By Chee S. Theng

As the 2015 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2015 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 338. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of AIME. Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2015 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH) and special-focus articles on gold processing, iron ore processing and coal processing. The 2015 Transactions consists of a total of 67 technical papers, encompassing all 22 papers published in 2015 in the Technical Papers Section of Mining Engineering (Vol. 67) and all 29 papers published in 2015 in Minerals & Metallurgical Processing (Vol. 32). Additionally, this volume contains 15 papers and one discussion that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2015 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2015

By Peter Zhang, Daniel Su

Following the first longwall excavation at a deep-cover gas well site, the pre-mining modeling prediction of longwallinduced casing deformations in the fully cemented production casing were in excellent agreement with post-mining Caliper survey results. However, after second panel mining, the post-mining Caliper survey revealed a large plastic deformation near the top of the Pittsburgh Seam. The focus of this paper is to identify the possible cause of such an anomalous deformation. Very high longwall-induced casing stress near a thick claystone layer at 23 feet above the Pittsburgh seam horizon was identified as the primary cause. Leaving the production casing uncemented or using softer cementing material between intermediate and production casings is identified as the best practice.

Feb 1, 2024

By Alvaro Veizaga, Samuel Cuellar

In recent years, Industry 4.0 has generated a change in the way companies in various industrial sectors design, produce and deliver products and services, and is focused on the interconnection of systems, the advanced access and management of large amounts of data in real time, and the implementation of emerging technologies such as the Internet of Things (IoT). Artificial intelligence (AI), machine learning (ML), digital twins (DT), robotics, virtual and augmented reality (VR/AR), among others [1]. DTs are accurate and dynamic virtual models that replicate physical systems, where it is possible to simulate and optimize operations before implementing real-world changes [3]. These features make it possible to reduce investment costs, minimize risks and improve strategic decision-making. These benefits are of utmost importance for tailings storage facilities (TSF), since they are facilities aimed at the safe storage of tailings and with the constant need for growth [4]. This paper evaluates the applicability of a DT in a TSF from a conceptual perspective, providing the advantages of its implementation, but also the barriers identified in the industry based on the authors’ experience.

Feb 1, 2025

By F. Segobia, M. Portal, F. Ysla, L. Goicochea

It is our responsibility to promote responsible and sustainable mining with new generations, promoting a culture of equality and respect. To fulfill this commitment, we are working with the SME UNC Student Chapter team, Newmont Yanacocha, BRG Women and Allies and the Museo de Agua y Tierra (MAT) to carry out the “Building our future” project. It is our responsibility to promote responsible and sustainable mining with new generations, promoting a culture of equality and respect. To fulfill this commitment, we are working with the UNC SME Student Chapter team, Newmont Yanacocha, BRG Women and Allies and the Museo de Agua y Tierra (MAT) to carry out the “Building our future” project. This project seeks to instill in new generations the importance of mining, integrating sustainable development objectives. We have the participation of Newmont Yanacocha and external professionals, who share their life stories and inspire participants from rural and urban educational institutions to pursue their dreams and aspirations. We believe that this project is important because it will help new generations understand the importance of mining and its role in the development of the country, covering the economic, environmental and social spheres. Since its inception in 2022, the project has positively impacted more than 500 participants.

Feb 1, 2024

By BERND SCHÖNHERR, JÖRG DEHNERT, PETER WINDISCH, JENS STOPP

The Quick-Erect Stopping System (QESS) offers a new way of reducing the radon exposure of miners in Germany, especially during remediation work in old mines. The QESS is a lightweight, modular and reusable construction kit of interlocking telescopic aluminum tubes, radon-proof foil and expanding foam. It is designed to seal off radon-rich parts of galleries within minutes. Originally, the QESS was developed to protect miners against radon exposure. Then, the QESS found the attention of several mine rescue teams at a German mining conference. Some mine rescue drills by The Student Mine Rescue of the Technical University Bergakademie Freiberg, Wismut Mine Rescue and Front Range Mine Rescue helped to improve the system and highlighted its potential for mine rescue operations. Now, the QESS is well-suited for small-scale mining. The QESS can be used to both protect miners from radon exposure and to support mine rescue operations. Moreover, the QESS was also successfully used in ventilation experiments.

By I. B. Tulu, M. M. Sears

In 2015, 40 longwall mines provided nearly 60 percent of U.S. underground coal production. During this time, about 80 percent of ground-fall-related fatalities occurred in areas where the mine roof was supported. In an attempt to better understand the status quo of current longwall support practices in the United States, during a period between 2010 and 2017, researchers from the U.S. National Institute for Occupational Safety and Health (NIOSH) visited a sample of 25 longwall mines representing nearly 50 percent of the currently active longwall mines operating in all of the major U.S. longwall producing regions. The data presented here indicate that the types and amount of roof support being installed in modern U.S. longwall mines have reduced ground-fall accident and injury rates to levels never seen before. However, the complete elimination of unintended roof falls in U.S. longwall mines has remained elusive. The data in this paper can be used by mine operators and engineers to determine where their chosen type and density of roof support occur on the spectrum of observations contained in this database. Additionally, this data can be used to enhance, supplement and support additional research on longwall gateroad support systems. 

By Stryker Magnuson

While probe drills are not strictly necessary for all projects, the incorporation and use of probe drills and pre-grouting adds capability and insurance to boring operations. Water ingress and unstable ground can be resolved before becoming a problem and resulting in costly delays through the use of enhanced, 360-degree probe drilling setups. To do this, proper design of the array of drill ports in the shield, matched to the possible ground conditions, is critical. For ground with exceptional water and instabilities expected, additional probing locations are low-cost additions that can lower risk and increase efficiency. In this paper we will look at recent and ongoing projects including the Lower Meramec Tunnel and Jefferson Barracks Phase 2. We will detail the design of those probe drill arrangements, and our overall recommendations for probing/grouting systems that best suit challenging ground conditions and keep projects running smoothly.

Jun 13, 2023

By C. N. Logan

The Southern Company is one of the nation's largest electric utilities and is the parent firm of five operating companies: Alabama Power, Georgia Power, Gulf Power, Mississippi Power and Savannah Electric and Power. Another subsidiary is Southern Company Services (SCS) which provides engineering and technical sup-port to the five operating companies. This technical support includes the procurement and supply of over 40.9 Mt (45 million st) of coal annually for the 22 coal fired plants in the system. Approximately 80 percent of this tonnage is purchased under long term contracts and the remaining 20 percent is purchased on the spot market. The coal is principally supplied from Alabama, Illinois Basin and the eastern Appalachian coal fields. Most of the coal is delivered by unit train and barge but one plant in Alabama receives all its coal by truck and conveyor belt.

Jan 1, 1990

By K. Oraee

A comprehensive, harmonic and sustainable development has always been a real concern of state policy makers. To reach such development, regional planning is an approach which is widely applied. This paper deals with policies adopted by a given country with rich mineral deposits, in order to accomplish a mining growth as well as economic development in relatively poor regions. In this regards, first, some worldwide experiences belonging to China, with large scale mining operations and Nigeria with a small scale mining industry, are studied. The mining industry in Iran is then considered as a case study. The study continues by categorizing and prioritizing Iranian regions based on their mining potential and the degree of development, using statistical analysis and Taxonomy and AHP techniques. Results obtained serve to provide recommendations as to where capital investments in the mining industry would produce highest returns. The approach used, together with the practical policies suggested in this paper, can be used to adapt appropriate strategies for mining development in a way that contributes to regional development and a more effective income distribution.

Jan 1, 2012

By G. J. Hartman

The Fort Cady in situ borate mining project involves recovery of boron from a mineral deposit located over 1400 feet below the surface. The resource recovery method is being developed using in situ mining technology employing weak acid solution injected directly into the ore body. As the acid contacts the calcium based ore (primarily natural colemanite), the contained borate values are digested as boric acid. This boric acid solution is then pumped to the surface by use of submersible pumps. At the surface the borate values are recovered as a finely divided solid white powder after a series of chemical reactions and precipitations resulting in the production of calcium borate. The refined product is then sold under the trade name CADYCAL 100.TM All environmental permits for up to a production rate of 90,000 tons per year have been obtained. These permits required an Environmental Impact study (EIS) for federal lands and an Environmental Impact Report (EIR) for the private portion of the property. Regulatory permitting required over 5 years to obtain all the various authorizations for this project. The ore body has an average thickness of 118 feet extending over 273 acres. At a production rate of 90,000 tons per year with only a 70 percent resource recovery allowance, in place reserves are sufficient to sustain production for over one hundred years.

Jan 1, 1997

The Global Mining Standards and Guidelines Group (GMSG) is building an international, multi-stakeholder community to advance the availability and use of standards and industry guidelines for the global mining community. Standards and guidelines are key strategic tools for operational excellence, enabling companies to move forward with efficient, innovative operations with reduced risk. Launched in May 2012, the GMSG is the first international center to bring together information, resources and collaborative projects for mining standards and guidelines, in an open, knowledge-sharing forum. The GMSG is supported by five partner organizations providing outreach and helping to guide GMSG activities: the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy and Exploration (SME), the Australasian Institute of Mining and Metallurgy (AusIMM), the Southern African Institute of Mining and Metallurgy (SAIMM) and the Surface Mining Association for Research and Technology (SMART). GMSG was formed under the CIM Surface Mining Society, though its mandate extends to include underground mining as well. ?SME is supporting the GMSG as a key international activity to advance the implementation of standards and guidelines in our industry, and to provide a forum for our members to access, and contribute to, projects and information to assist their operations,? said SME Executive Director David Kanagy. ?We see the GMSG as a good example of ways the major mining associations can work together for the benefit of all our members.? The GMSG charter encompasses all standards and guidelines that apply to mining; however, a number of subject areas are now being spearheaded by six working groups, namely: ? Access and usage of data from mobile mining equipment onboard systems. ? Operational safety. ? Situational awareness (namely, a unified equipment operator interface). ? Underground operations. ? Asset management and operations data definitions and KPIs. ? Energy in communition.

Oct 1, 2013

By W. Burr Bennett

The prestressed concrete industry in particular, and the precast concrete industry to some extent, are rank newcomers to the concrete construction field compared to the cement, ready-mixed or concrete masonry industries. This young industry reflects its youth and vigor in its enthusiasm, optimism and the belief that it can reach any goal it chooses to set -- and it is setting its sights high. The prestressed and precast concrete industry fully expects to become the major structural and architectural material by the 1980's. Before exploring how the industry expects to reach this goal, a brief look at the origins and the growth of the industry may be useful in an evaluation of the feasibility of this goal. It was always recognized that concrete, strong and efficient for supporting loads which cause compression, was weak and inefficient when used to carry loads which induce tension. Thus the reason for reinforced concrete in which the concrete efficiently carries the compression in a flexural member while low grade steel bars reinforce the concrete in the areas 'of tensile stress. (Fig. 1). The steel being relatively inexpensive, can passively, but quite effectively carry tensile force while the concrete carries compression. The concrete in contact with the reinforcing also protects the steel from corrosion and acts as insulation to provide a superior "built-in" fire resistance. The major disadvantage of reinforced concrete relative to its main competitor, steel, is its weight in relation to its load-carrying capacity. Reinforced concrete systems, such as waffle slabs, I-beams, thin shells, etc. ,

Jan 1, 1971

By Joaquin Ruiz

Naica consists of at least 10 mantos and 40 chimneys that have produced over 15 million tens of ore with 10% Zn, 13% Pb and 13 oz/ton Ag. The ore occurs in thick-bedded, folded Cretaceous limestone. Fractures and 26 Ma old felsite dikes with an initial strontium isotopic ratio of 0.708 localize the mineralization. The mantos follow the dikes and have abundant early skarn with manganohedenbergite, calcic garnet, idocrase, quartz, calcite, wollastonite, schellite and later sulfides. The chimneys arise from the mantos and change from silicate-rich to silicate-free sulfide limestone replacements. Carbon, oxygen and sulfur isotope data on carbonates, silicates, sulfides and sulfates are compatible with a single evolving (magmatic?) fluid.

Jan 1, 1985

By Robert A. Bauer

Introduction A longwall mining demonstration currently in progress in the Herrin (No.6) Coal Member near Benton, Illinois, involves the extraction of three adjacent panels by the longwall method. The first panel was completed in May, 1977. The Illinois State Geological Survey is involved in this project for two reasons: (1) to detail the geology of the roof and relate the geologic features to the behavior of the roof during mining operations, and (2) to study the nature and occurrence of coal balls (carbonate petrifactions of peat) encountered during this demonstration. General Geology of Area The stratigraphic sequence of beds immediately above the No. 6 Coal in this area, ranging from oldest to youngest, is: gray shale (Energy Shale Member), black carbonaceous shale (Anna Shale Member), and argillaceous limestone (Brereton Limestone Member) (figure 1). In some areas of the mine, where one of these units may rest directly on the coal, one or more of the members is absent from the stratigraphic sequence. The nature of roof for the area is shown in figure 2. It is greatly exaggerated in the vertical direction. The Walshville Channel, 11.3 km west of this mine, was a river at least in part deposited at the same time as the coal. The gray shale wedge on top of the coal, which thins away from the channel, is thought to represent an overbank deposit of mud from the channel. The next layer deposited on top of the gray shale, and on the coal not covered by gray shale, is the black carbonaceous shale, believed to represent a mud deposited in a brackish environment. The area where the roof lithologies change rapidly from one shale to

Jan 1, 1977

By C. Pace, D. Darlington, A. Montera, C. Lingren

"A phosphate beneficiation plant in Utah is using isotope-based Prompt Gamma Neutron Activation Analysis (PGNAA) technology to analyze the entire slurry streams of the incoming feed and final product in order to adjust the flotation circuits in near real time and optimize the plant output. The plant has gained greatly improved visibility/control and has reduced product variability for improved profitability and product quality. This paper takes a look at the economics as well as application details and the difference this technology provides in a phosphate application. SIMPLOT PHOSPHATES INTRODUCTION Simplot’s Vernal, Utah Phosphate Mine and Mill are located in the northeast corner of the state in the Uinta Mountains along US Highway 191, eleven miles north of the town of Vernal. The phosphoric acid and fertilizer plant fed by the Vernal mine is located 94 miles Northeast of Simplot Phosphates in Rock Springs, WY.At the Vernal plant, loader and shovel mining to 85 Ton capacity trucks is done at an annual rate of 3.8 Million tons of ore. Run of mine ore is crushed in a mineral sizer to minus 14 inch diameter at the rate 11,500 tons a day and transported to the SAG Mill’s 130,000 ton surge stockpile by overland belt. ORE RESERVES The ore is a Phosphoria Formation of sedimentary rock type dating to the Permian Age. The ore body rests over a 25 mile area on Weber Sandstone from the Pennsylvania and Permian geologic period. Layers of Phosphate Rock can vary in thickness from 0.3 up to 2.1 feet, alternating with layers of Mudstone. The eastern edge of the ore’s body Panel “G” runs 16 feet deep with a feed grade of 21.5% P205 with lower MgO diluents of less than 2.79%."

Jan 1, 2016

By J. Reyher, R. Bratton, G. Luttrell, B. Li

"Flotation is regarded as the best available method of upgrading minerals and coal fines. However, its efficiency deteriorates rapidly with decreasing particle size. Further, ultrafine concentrates are difficult to be dewatered economically, forcing companies to discard part of the ultrafine materials to impoundments. To overcome these problems, a new method of separating and simultaneously dewatering ultrafine particles has been developed. Following extensive laboratory-scale test work, the process, known as hydrophobic-hydrophilic separation (HHS), has been tested successfully in continuous operations at proof-of-concept (POC)- and pilot-scale tests. The results show that the HHS process is capable of producing high quality clean coal with high recoveries and low moistures. INTRODUCTION Coal preparation plants are designed with up to four parallel processing circuits for treating coarse (> 12 mm), intermediate (12x1 mm) small (1x0.15 mm), and fine (<0.15 mm) particles. The plus 0.15 mm fractions can be effectively cleaned efficiently with gravity separation methods (Wills, 2006). At present, the only commercially viable option for cleaning the finest fraction is froth flotation (Yoon et al., 1999). In flotation, air is dispersed in the form of small air bubbles in a tank in which coal fines are suspended. The small air bubbles selectively collect the hydrophobic coal particles and float to the surface, forming a froth phase which overflows into a launder. As is well known, ultrafine coal particles of less than 30-50 µm are difficult to be collected by the air bubbles, resulting in low recoveries. Furthermore, fine particle flotation suffers from low carrying capacities and poor selectivity due to entrainment problems. (Bethell et al., 2005; Luttrell et al., 2014). In addition, the froth products containing ultrafine coal are difficult to dewater. Mechanical dewatering in general becomes inefficient with decreasing particle size due to small cake porosity and high surface area, resulting in high moistures (Hucko et al., 1988). The cost often becomes prohibitive with particles of smaller than ~45 µm (Bethell et al., 2005). Moreover, the high-moisture products are difficult to handle and incur high shipping costs and lower thermal efficiencies (Honaker et al., 2013)"

Jan 1, 2016