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By W. K. Connor, O&apos

The Bureau of Mines is investigating the Co and Mn resource of the West-Central Arkansas District, including field investigations, mineralogical characterization, beneficiation, and hydrometallurgical tests. The deposits occur within the Ouachita Mountains and are con-trolled structurally, occurring along the axes of anticlines making up the mountain ridges. Brecciated novaculite is cemented with a mixture of Mn oxides, primarily cryptomelane and psilome-lane. Cobalt is concentrated within a particular Mn oxide phase, lithiophorite. Chemical analyses on head samples reported up to 25 pct Mn and 0.17 pct Co. Magnetic separation yielded products with up to 41 pct Mn and 0.22 pct Co at recoveries of 95 pct Mn and 93 pct Co.

Jan 1, 1991

By Marcelo de Oliveira, Antoine Allanore, Dennis P. Chen, Davide Ciceri

Potassium fertilizers (potash) are mined in a handful of countries in the Northern Hemisphere. Potash is either expensive or unavailable to the farmers of the Southern Hemisphere. Alkaline alteration of K-feldspar rock (ultrapotassic syenite) in autoclave in the presence of Ca2+ generates a mixture of K-bearing calcium-aluminum-silicate-hydrate (C-A-S-H) minerals that potentially can be used as an alternative local fertilizer. This work investigates the effect of processing temperature (200 °C, 220 °C, and 230 °C) and time (from 0.5 to 3.0 h) on pH, mineralogy, and elemental availability of the C-A-S-H mineral mixture. Increasing temperature results in an increased conversion of K-feldspar and increased content of both the mineral tobermorite (Ca5Si6O16(OH)2·4H2O) and amorphous phase in the resulting C-A-S-H mixture; increasing time results in an increased conversion of α-dicalcium silicate hydrate into tobermorite. The amount of K leached from the mixture is relatively constant across all processing conditions. Hydrothermal alteration in autoclave of K-feldspar-bearing rocks such as ultrapotassic syenite permits the synthesis of a potential potassium fertilizer which alkalinity and mineralogy can be tailored according to soil requirements.

May 22, 2020

Dravo Corporation was founded in 1891 and has long been recognized as a major domestic engineering and construction firm headquartered in Pittsburgh. In 1977, Dravo had revenue of $852.2 million with international business activities contributing $248 million; quite a different picture than envisioned at the turn of the century. Engineering and construction activities still dominate Dravo's most recent history and will do so for the immediate future. However, fluctuations in capital spending by large industrial sectors of our economy during the late sixties were affecting Dravo's planning for continued growth along its traditional lines of business. Diversification was a possible solution to smooth out the upward trend in corporate earnings. One large result of these continuing efforts was the formation of Dravo Lime Company, a vertically integrated, proprietary chemical supplier for the air pollution control market. Briefly retracing the seventies, the passage of the Federal "Clean Air Act" in 1970 supplied the impetus for Dravo Lime Company. This law promulgated limits on the emissions of sulfur dioxide (SO2) from large stationary sources that would affect local air quality. The major industry that felt the brunt of this regulation was the electric utility industry, especially those generating electricity with coal-fired boilers. The law hastened the development of a new industry, flue gas desulfurization (FGD), and is composed of three major segments: (1) the electric utility, (2) the FGD equipment suppliers (the scrubbing modules), and (3) the scrubbing chemical suppliers. Dravo's experience suggested the equipment end of the business but market analysis indicated that our long range corporate goals could be better attained by investigating the chemical processes involved in the removal of the SO, gas. The result being Dravo Lime Company. This paper will briefly describe the Thiosorbic lime scrubbing process and review our innovative mine and calcining facility.

Jan 1, 1978

By M. L. Leming

The mechanisms of Alkali-Silica Reactivity (ASR) are briefly reviewed, test methods are examined, and typical specifications are discussed. In addition, views on responsibility of the aggregate supplier regarding specifications are presented.

Jan 1, 1995

By R. Froidevaux

Geostatistical estimation techniques were customized to enable forecast of production figures at the Silver Bell uranium mine (Uravan District). Surface drill hole data were used to provide a block model of kriged estimators of average uranium grades. The recoverable figures, such as ore-waste ratio and ore grade, are then deduced from regressive curves previously obtained from underground information and production data. Cross-validations of the entire model were performed and were found positive.

Jan 1, 1981

By Rodrigo Jerez

This paper describes a Mixed Integer Linear Programming model that was developed for planning the coal operations at Mountain Coals, Inc., in Kentucky. The model incorporates the use of stockpiles as practiced and allows the operator to find the least cost combination of raw coal feeds, washing densities and blending to produce the different quality coals as required by the coal contracts.

Jan 1, 1984

By R. Benito

The publication of the Lerchs Grossmann paper in 1965 outlining a threedimensional graph algorithm for ultimate pit definition set the standard for the mining industry regarding pit optimization. Although the algorithm provides a solution from a static standpoint (i.e., assumes instantaneous mining), it is widely used for commercial packages to generate ultimate pit limits and intermediate phases. However, the solutions delivered are presented in canned reports lacking connection to the original data, which prevents further data analysis and extended reporting. The approach presented in this paper attempts to overcome such barriers by performing openpit optimization through databases. An adaptation of the Lerchs Grossmann graph algorithm is used to generate nodes, arcs and tree structures in customized tables to determine the maximum closure of a graph.

Nov 1, 2013

By Frank Agyemang, Zainab Nasrullah, Richard LaDouceur, Mehran Saddat

To sustain the circular economy, defence applications, and other renewable technologies, recycling rare earth elements (REEs) and other critical elements from their secondary resources is important. This cause has resulted in rigorous research and development for viable extraction and separation of REEs. Previously, Sm-Co recycling has been done with technologies, which fall under the categories of pyrometallurgy, physical separation, and hydrometallurgy. All these methods have limitations associated with energy, cost, and environment. Reportedly, the chemical leaching technology has successfully recovered and separated Sm-Co. Still, it has limitations associated with slow mass transfer and leaching kinetics, and there is a need to intensify the process to make it time efficient. This approach has also adversely impacted the environment by an extensive use of toxic, corrosive, non-selective, and expensive reagents. In this research study, chemical leaching of Sm-Co was performed using this new class of solvents, Deep Eutectic Solvents (DESs), which fall under the category of ion metallurgy. Four different DESs were used, proven to be green, non-toxic, biodegradable, cheap, and selective for cobalt over samarium by 82% leaching conversion. To improve the slow mass transfer and leaching time, this new technology of resonant vibratory mixing (RVM) was also tested. RVM intensifies mixing by establishing near instantaneous, low energy mixing conditions through resonance. It has been shown to improve the adsorption kinetics and was tested for the leaching kinetics. Four combinations of DESs were prepared, which are made up of two quaternary salts: Choline Chloride and Tetra Butyl Ammonium Chloride, and three organic compounds: Oxalic Acid, Urea, and Ethylene Glycol. These combinations were used for chemical leaching of Sm-Co with leaching factors of time, temperature, and type of DESs. After leaching, the samples were tested with and without resonant vibratory mixing with conditions of time, intensity (%), and type of DESs. Samples were analysed with Induced Coupled Plasma - Optical Spectroscopy (ICP - OES). Future work will involve a life-cycle assessment to assess the RVM technology with other conventional mixers, and an extensive study of DES properties to improve selective leaching.

Feb 1, 2025

By Christopher J. Bise

It is somewhat reassuring to note that the United States has an abundance of coal reserves which can be used to bridge the widening gap between the nation's energy production and consumption. The U. S. Bureau of Mines has recently established a demonstrated coal reserve base of 434 billion tons. (31)(Figure 1) As can be observed, the major percentage of the reserves is in the West. Although surface coal mining in the West has been gaining increased attention in recent years, western reserves that must be deep mined are significantly greater. Though deep mining activity in the west is very limited and accounts for less than 2% of the annual production, the primary reason, quite probably, is the greater thickness of the seams as compared to those found in the East. Forty-five billion tons of the western demonstrated coal reserve base for underground mining are in seams greater than 10 ft. in thickness. (37) Thick coal seams do not lend themselves readily to extraction with the underground mining methods practiced in the United States today. Experiences from the practices in other countries can serve only as guidelines. Consequently, a concerted effort is necessary to overcome the technical difficulties.

Jan 1, 1975

By S. E. Knalafalla

The availability of a fluid whose gross behavior sharply changes in a magnetic field without affecting its rheologic characteristics has been recently demonstrated. A colloidal solution of a ferrimagnetic material, such as magnetite, in a liquid that is immiscible with and lighter than water is projected for use in selective separation of particles according to their density spectrum in a continuous fashion. Magnetic levitation forces were created as an antigravity field when the fluid was properly placed in an inhomogeneous magnetic field. Five spherical non¬magnetic objects with densities ranging from 2.70 to 11.35 gram cm ' were made to float or submerge at will in a 0.96-gram cm-3 density fluid placed at vertical magnetic field gradients ranging from 0.2 to I kilooersted cm-1. The magnetic levitation farce in dyne cm-3 was found to vary linearly as a function of the object-fluid density mismatch with a slope equal to one g, the acceleration due to gravity.

Jan 1, 1972

By Kenneth A. Grace

Each and every mining operation from a simple sand-and-gravel pit to the largest integrated mine-mill-concentrator-smelter-refining complex has, as its foundation, a quantity of extractable natural resource the reserves. Without reserves, there is no mine, and any concentrating or extracting plant, no matter how sophisticated, is simply so much scrap metal. And, of course, without resources there are no reserves. It is remarkable, therefore, especially in this age of careful planning, high quality engineering, and state-of-the-art financial analysis, that such a fundamental and vital item is so little understood and the subject- of so much confusion. Time and time again it has been the experience of the author, when called in to a mining operation that has run into trouble in reaching projected production targets, to find that the designed-for tons were not reaching the concentrator/extraction plant, and/or the grade of such tonnage was substantially below the forecast and design grade of the plant. The mill blames the mine for delivering below standard tons and/or grade and the mining engineer blames the geologist for overly-optimistic assessment or incorrect interpretation of the deposit. The geologist blames the mining and metallurgy division for wrongly interpreting his data and conclusions, or simply fouling-up a fine orebody.

Jan 1, 1983

By J. Sidhom, W. Fourie

"As the mining industry continues to face difficult challenges the need to persistently focus on productivity and utilization of labor and equipment costs will intensify. With these challenges in mind, Joy Global is helping to bring mining performance and analytics to the next level. By evaluating underground haulage, a significant component of the Room and Pillar mining value stream, variables have been identified and sensitivities have been performed to show opportunities to balance and streamline throughput. As a result of applying operational excellence tools to the mining environment, Joy Global is seeking to optimize mining performances by limiting waste, simplifying the process, increasing productivity and machine utilization, as well as removing workers from harm’s way. These days it’s not enough to work harder; mines have to work smarter. Improving efficiency, reducing costs, increasing safety: these are no longer ‘nice to haves’, they are ‘must haves’. Starting with the best products and the right people is a first step, but then what? How do mines take their operations from just OK to being a top performer? By using operational excellence principles aimed at eliminating waste, simplifying processes, automating where possible and removing people from harm’s way. The fundamentals of operational excellence (OpEx) are based upon the DMAIC process, which stands for define, measure, analyze, improve and control. DMAIC is an improvement cycle that helps with, for example, haulage optimization by: defining the issues and problems in the process as well as the areas of improvement; measuring and collecting mining operational data by time study and equipment monitoring system; analyzing through sensitivities and production modelling to determine root causes; then improving the performance and controlling the operation. Joy Global uses Joy OpEx or ‘lean’ principles inside its organization to drive efficiency, but it also helps its customers employ them to achieve new levels of productivity and safety. These same principles can be applied in most situations to streamline processes, improve operations and deliver value. As applied to mining, OpEx is seen as moving the needle on value creation by first identifying the value stream, then analyzing the areas that are not optimized. Once defined, these areas are ‘designed out’ of operational processes to create an automated operational flow. At a US coal mine, Joy Global was brought in to apply Joy OpEx principles to optimize mining and haulage to improve productivity and reduce costs. This multi-phase process started by defining the existing systems challenges to start finding areas for improvement."

Jan 1, 2017

By Ali Ahmadi, Andreas Rausch, Angela Binder, Stefan von der Mark, Dhananjeyan Jeyaraj, Jana Thomas, Nils Nöther, Stefan Wittek, Thomas Ulrich, Eleni Gerolymatou, Mario Kolling, Helmut Mischo, Michael D. Martin, Tugba Sen, Jens-André Paffenholz, Erik Farys, Oliver Langefeld, Wilfried Ließmann

This paper outlines the MOVIE project, which is dedicated to the development of a digital twin for an underground laboratory at the research and education mine “Forschungs- und Lehrbergwerk Reiche Zeche” in Freiberg (Germany). Data from induced rock deformations and temperature fluctuations is collected using fiber-optic sensors. The objective of the project is to establish a virtual laboratory for real-time analysis of the interactions between geology, geomechanics, geometry and ventilation. This will be achieved by integrating models from these disciplines with artificial intelligence, creating a sophisticated hybrid model. The insights gained will enhance safety and efficiency in mining through improved digital planning options, ultimately contributing to more effective resource management and operational decision-making in different mining environments.

Feb 1, 2025

By Muhammad Hashim Rasa, Ali Aras

Recovering valuable metals from tailings not only provides a source of income but also helps conserve natural resources, thus reducing the environmental impact of mining activities. This study aimed to recover cobalt using tailings of the Küre flotation plant, which were determined to contain 0.17% Co. Flotation tests were conducted on samples taken from the tailings to investigate the effects of pH and pH conditioning time, as well as types and amounts of depressant, collector, and frother on the grade and recovery of Co in rougher flotation tests. Optimal flotation conditions were determined to be pH 6, a pH conditioning time of 7 min, and dosages of 50 g/t, 100 g/t, and 20 g/t of sodium hexametaphosphate, X-231, and DF250, respectively. According to the rougher flotation test results, a concentrate with a Co grade of 0.46% and a Co recovery of 84.15% was obtained. In the concentrate obtained using cleaner flotation tests, the Co grade increased to 0.49% and Co recovery increased to 90.56%. These results show that froth flotation, carried out with the appropriate reagents, is a successful method for recovering Co by enriching the flotation plant tailings.

May 17, 2023

By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

By J. Drelick

Among the wide variety of modern surface chemistry analytical techniques, contact angle measurements still remain attractive for wetting characterization of solid surfaces. The captive-bubble and sessile-drop techniques are the most popular methods for the examination of flotation systems. Systematic measurements of advancing and receding contact angles for several three-phase systems using the captive-bubble and sessile-drop techniques show that the contact angle measurements depend on the technique used and may differ significantly for some heterogeneous and rough solid surfaces. Importantly, it was found that these discrepancies in contact angle measurements depend on the bubble (drop) size. Contact angles as measured with the static captive-bubble technique are compared with those measured with the dynamic captive-bubble technique, in which the capture of a bubble at the solid surface results after buoyant transport and attachment The dynamic captive-bubble technique allows for the formation of much smaller bubbles than is possible with the static placement technique in which a bubble is placed at the solid surface with a microsyringe. Although this dynamic technique cannot be recommended for the systematic wetting characterization of solid surfaces, its significant advantage is the ability to examine the contact angle/bubble size relationship over a wide range of bubble sizes, from several micrometers to several millimeters in diameter.

Jan 1, 1995

By Peter Schmäh

Pipe-jacked tunnels are considered for a large variety of applications from water and sewage, cable ducts to challenging pipeline crossings or landfall construction. In most cases, Slurry MTBMs are used to carry out these projects. Continuous further development of technological features for pipe jacking plays a key role to overcome feasibility limits and to meet increased project requirements. As tightened safety regulations in terms of accessibility and escape routes increasingly limit the options of small segment lining tunnels in the diameter range below 4 m, 13 feet, pipe jacking has partially taken over. During the last decades, a growing number of large-diameter and long-distance pipe jacking projects have been completed. Experienced contractors successfully use the technological capacity of the MTBM equipment. The machine and cutting wheel have to be designed according to the ground conditions. Bentonite lubrication and interjacking stations are key factors to keep push forces moderate. For long pipe jacking drives, a so-called push module can be installed in the machine can, to be able to switch from pipe jacking to segment lining in case the machine gets stuck. The overall aim is to provide clients and the tunnel construction industry with safe and economical solu- tions for successful project execution. This presentation will present international milestone projects and will also discuss the latest developments in automation, related opportunities and limitations, and the future of digitization and artificial intelligence in pipe jacking.

Jun 23, 2024

By J. J. Whittaker

Zaldivar is an open pit copper mine operation located in the Atacama Desert, in northern Chile. The plant produces Cu cathodes using 4 solvent extraction trains. The plant was started up May 1995. Since 1996 the plant has been using on-stream analyzers based on X-ray fluorescence and titration for process monitoring and control. Elemental analyzer alone is not able to provide the critical information for plant operation, it has to be complemented by on-stream titrators integrated to one sampling system. The analyzers are located in a prefabricated shelter. The analyzer system project, operation and performance issues are the main topic of this paper.

Jan 1, 1999

By T. McWaters

Miami Copper Company began a block-caving operation in 1911 using a gravity mill to separate copper minerals from the Pinal Schist host rock. The tailing was deposited by the upstream method using perimeter launders and spigot valves in six canyons adjacent to the mill until 1932. In 1928 the larger and more distant Solitude tailing pile was developed which by 1932 was receiving all tailing except for upsets. In 1925 Miami Copper converted its gravity mill to flotation which began to produce higher sulfide copper recoveries.

Jan 1, 1990

By Georgene Renner, Chee Theng, William Gleason

"In February 2018, drawn in part by the states’ proud mining heritage, SME took its Annual Conference & Expo to Minneapolis, MN for the first time. More than 5,000 people and 554 exhibitors converged on the Minneapolis Convention Center for three days of networking, exhibiting and technical sessions.The state’s mining legacy, one that continues today, is fueled in large part by its vast iron ore resources in the northern part of the state. The historical significance of the mines in the Mesabi Range, otherwise known as the Iron Range north of Lake Superior, cannot be understated. “Mining is a way of life here,” said U.S. Congressman Rick Nolan of Minnesota’s 8th Congressional District. A native of the Iron Range, the three-term U.S. congressman was one of the featured speakers of the opening keynote session. “We like to think we contribute enormously to the well-being of this country and the world. We were the source of the iron ore and steel that helped win two world wars. And we like to think that we are part of the progress that has taken place in the United States ever since.” Nolan kicked off the keynote sessionthat focused on innovation and its part in the mining industry. The session included Rene Aquilar, vice president of corporate affairs and sustainability, Antofagasta Minerals Group; Bob Anderson, vice president for research and development, 3M; Rolf Weberg, executive director, Natural Resources Research Institute, University of Minnesota-Duluth and Christopher Beck, executive vice president and president, Nalco Water. The panel session looked at U.S. and global minerals production, and the importance of the United States to maintain a major role in the minerals industry, both as a producer and as a technology leader. The panel also touched on the global mining industry and the issues that impact mining around the world. Sustainability, the use of water in mining and earning a social license to operate were among the topics discussed by the panel.Speaking of the importance of mining, Nolan conceded that talking about the benefits of mining to the crowded auditorium at the SME conference might be akin to a preacher speaking to the choir, but, following the adage that all politics are local, he continued to illustrate his point by emphasizing the importance of mining to the Great Lakes.“A study by Homeland Security concluded that 13 percent of the nation’s GDP comes out of Lake Superior through the locks at Sault Ste. Marie and most of that is iron ore,” said Nolan. “That study found that, if those locks fail, it would create a national depression. It would put millions of people out of work. That ore and those minerals supply the steel mills, the auto industry, the heavy industrials. They are the heart of our economy. The study concluded that if the states that make up the Great Lakes were a nation, it would be the fourth largest economy in the world.”"

Jan 5, 2018