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By Katerina Adam

During wet grinding the electrochemical interactions between grinding media and pyrrhotite not only accelerate the media wear but also adversely affect the flotation response of the sulfide mineral. A possibility of remedying the adverse effect on its floatability by applying electric potentials to grinding media was examined. Flotation tests, Auger electron spectroscopy and x-ray photoelectron spectroscopy were used to study the surface properties of pyrrhotite. Although anodic polarization of the steels increased the metal loss by corrosion, the flotation recovery of pyrrhotite was increased. In the case of cathodic polarization, the flotation recovery improved in a narrow range of overpotentials. At higher cathodic overpotentials, however, the floatability of the mineral was progressively lowered although the corrosive wear of grinding media might be reduced.

Jan 1, 1984

By A. D. Hammond

Vanadium is a transition metal, ductile, silver-gray metal. It is harder than most metals and steels and it has a good resistance to corrosion, it is stable against alkalis, sulfuric and hydrochloric acids. Vanadium is oxidized in air about 660 °C, although an oxide layer forms even at room temperature. The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states 2-5. In aqueous solution the colors are lilac V2+, green V3+, blue VO2+ and, at high pH, yellow VO42-. Considered to be as abundant as zinc, metallic vanadium is not found in nature, but it is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4), vanadinite (Pb5(VO4)3Cl), associated to the uranium mineral carnotite (K2(UO2)2(VO4)2?3H2O) and in a vanadium mica called, roscoelite K(V3+,Al,Mg)[(Si,Al)4O10](OH)2. Other important vanadium ore oxides are montroseite (V,Fe)O(OH) and corvusite (Na,Ca,K)V8O2.4H2O. Much of the world's vanadium mine production comes from magnetite-hosted deposit and to a lesser extent, in sedimentary-hosted sandstone. Vanadium is also present in bauxite and in fossil fuel deposits such as crude oil, coal, oil shale and tar sands. In crude oil, concentrations up to 1,200 ppm have been reported. A significant vanadium production comes from the processing of petroleum residues, fly ash and recycling spent catalysts. In 2011, metallurgical applications accounted for 93% of the use of vanadium. Here, an alloy called ferrovanadium is utilized to strengthen steel to be used as rebar in the construction industry, in the manufacturing of axles, crankshafts, gears and chassis in the automotive and transportation industries and in the manufacturing of high-speed tools. In the aerospace industry, vanadium is utilized as a titanium alloy in the manufacturing of airframes and jet engines. The reason for the wide use of vanadium as alloy is its high strength-to-weight ratio, the highest of any engineered material on earth. The major non-metallurgical use of vanadium is in the production of catalysts for the chemical industry. The most commercially important compound is vanadium pentoxide (V2O5), which is used as catalyst in the production of sulfuric acid.

Feb 23, 2014

By Keith Whitworth

The USSR, over the last 20 years, has continued to increase its out-put year by year and it is now almost four times what it was at the end of the Second World War. In 1975, it exceeded 700 million tons of run-oi-mine coal (all ranks) which amounts to over 20 percent of world output. This rapid progress has been due to modernization of the industry, by means of increased mechanization and automation and the development of new machines and systems for underground workings and by the expansion of open-pit workings and the development and implementation of larger earthmoving machines.

Jan 1, 1977

By A. J. Guse

The primary limiting factor for hoisting capacity from great depths is the self-weight of steel wire ropes. Steel wire ropes are very suitable for mine hoisting due to their high strength and durability, but have the negative characteristic of a low strength/weight ratio. Also, as hoisting depths increase, the service life of steel wire ropes decreases due to the higher stresses and physical effects on the ropes. The significantly higher strength/weight ratio of synthetic ropes offers the primary advantage of hoisting a larger payload with a similar size rope and hoisting plant. The beneficial properties of synthetic ropes could be used to improve the overall economics of deep underground mining both for new deep shaft projects and for existing mining operations expanding to deeper orebodies. A research and development program has been initiated to evaluate the suitability of a fully synthetic rope for the mine hoisting application.

Feb 23, 2014

By Thomas A. Mekelburg

Due to a tight ash constraint on the clean coal product and difficult middlings washability characteristics, a considerable amount of coal was being lost in the jig middlings at the Monterey No. 2 Mine. An investigation was conducted into circuitry to recover this lost coal with minimal effect on the total clean coal ash. A reverse two-stage hydrocyclone system cleaning at low specific gravities was selected. This system is currently recovering approximately 5.8 kg/s (23 tph) of 11.5% to 12.5% ash coal. The specific gravity of separation for the system is about 1.5 and the probable error is 0.13.

Jan 1, 1984

By Samuel Polinsky, Lawrence W. Bierman, Wayne Perkins

[A column float beneficiation plant using 9, 8.5 foot diameter, cells was constructed by the Simplot Company and the Smoky Canyon Facility in the fall of 1986 and has been in operation since May of 1987. The float beneficiation process was developed jointly by the Simplot Company and the Bureau of Mines (Salt Lake City, Utah) which incorporates the Bureau's bubble generator design and chemistry system based around the reverse float technology, (Albany Bureau of Mines, Application of Carbonate-Silica Flotation Techniques to Western Phosphate Materials, Rule, Dallenbach , Larsen, RI8728, 1982) . This chemistry has been modified by Simplot in both patented and unpatented improvements. The objective of the beneficiation process was to reducethe A1203 content in the overall pipeline concentrate by 0.2 wt z. Therefore, a process stream was identified in the mill circuit which provided an opportunity to isolate and treat 1100 tons per day of poor quality phosphate concentrates The process allows recovery of approximately 15% of the mill concentrates, otherwise unsuitable for fertilizer production. The alternative would have been to waste this ore. Wasting would have resulted in considerable ore loss, increased mining costs and required additional products grinding. ]

Jan 1, 1989

By Richard M. Winar

In September of 1988, the United States Environmental Protection Agency (US EPA) published final regulations that effect owners and operators of underground storage tanks (USTs). These regulation include stringent technical requirements for owners and operators of USTs containing petroleum and certain hazardous substances. The technical requirements effect both new (those installed after December 1988) and existing USTs and include notification; performance and operating standards; release detection, reporting, investigation; release response and corrective action; and closure requirements for out-of-service USTs. The USEPA also published final regulations regarding financial responsibility requirements for owners or operators of petroleum USTs in October of 1988. These regulations require owners or operators of petroleum USTs to demonstrate financial responsibility for the costs of corrective action and compensating third parties for bodily injury or property damage caused by releases from petroleum USTs. Like thousands of other industries, the mining industry must become thoroughly familiar with these new regulations in order to properly manage their UST systems, ensure compliance, and understand other ramifications imposed by these regulations.

Jan 1, 1990

By V. F. Hollister

Although it is apparent that porphyry copper deposits may have formed in the Andean orogen from Permian time onward, commercial deposits thus far developed appear to have Cenozoic ages only. Following Chilean useage, the porphyry deposits are divided into either: (a) a stockwork, or (b) a tourmaline breccia model. Stockwork type deposits tend to occur on major strike-slip structures which may be either transcurrent or transverse faults related to plate movements, while the tourmaline breccia type may more frequently form independently of regional faults. Stockwork types may be conjugate fractures that intersect and ramify as a network of veins and veinlets, cutting altered rock, and genetically related to a major regional fault, or in other cases they may reflect the intersection of two large fault structures. Circular fracture patterns may more rarely occur in stockwork deposits in response to a specific intrusive. Tourmaline breccia types are characterized by circular and radial fractures genetically connected in some way with tourmaline breccia pipe development or an intrusive piercement that preceded it. Each structural model contains mineralized intrusive8 which have a close time-space relationship to ore and in each model, mineral paragenesis is similar, regardless of age or location in the plate. Also, each model contains the same type of alterntion halos (phyllic, argillic, prophllitic) as are developed in intru- sive centers in porphyry copper deposits found in North America. The potassic zone is exposed best in the older deposits. Examples of each type of deposit are illustrated, demonstrating the feature evolved.

Jan 1, 1973

By P. A. C. De Ruiter

The Lower Cretaceous salt deposits of the Gabon Basin and Congo Basin were said down on ton of an Burly Cretaceous Lato Jurassic, continental graben fill that represent!) the rifting phase of the Afro-American continent. The salt 13 characterized by high percentages of potash and magnesium salts and the scarcity of sulphates and carbonates. The salt probably originated from a brine that was already enriched in high-soluble salts before entering the Gabon Congo basins. Their low-solubility equivalents are found in the Cuanza Basin of Angola. Commercial mining of the potash salt is only possible in those onshore areas where it is essentially undisturbed, shallow and of the right chemical composition. These conditions are net in Congo where the Holle mine produces from rich sylvinite deposits.

Jan 1, 1978

By Enrique Levy

Central America is graduating this year into large scale mining with the start up of Inco's multi-million dollar nickel laterite processing plant in Guatemala. In the other extreme of the Isthmus in Panama Texas Gulf Sulphur is doing check diamond drilling and foundation test drilling at the Cerro Colorado copper porphyry. The higher price of gold and silver has spurred development and exploration of several small precious metal mines. The purpose of this presentation is to make a brief resumé of the most important mines operating in the area and a list of significant exploration projects. Also, tables will be shown to compare mining codes and taxes. Unfortunately these tables lack information on Panama. Before starting I like to express my appreciation to Kennecott Copper who permitted the use of some of the data compiled by the author on their behalf during the year 1975. Other persons which did not want to be named also have my gratitude.

Jan 1, 1977

By William P. Lorenz

Overlying the sulfide mineralization at Anamax Mining Company's Twin Buttes Mine is an oxidized zone up to one hundred meters in thickness. The principal copper minerals in this zone are chryso-colla, tenorite, cuprite, native copper and copper-manganese-iron wad. This ox¬idized zone also contains minor amounts of uranium ranging in concentration from 0.002 to 0.010 percent. Since pit development through 1980, some 38 million tonnes of oxide ore with copper contents greater than 0.6 percent have been brought to the surface. Copper in the oxide ore is extracted at Twin Buttes in, an agitated sulfuric acid leach plant followed by solvent extraction and electrowinning producing 90 tonnes per day of copper cathode. During leaching of the oxide ores small amounts of uranium are solubilized along with the copper values. This is not limited to Twin Buttes as most acidic copper bearing leach solutions throughout the southwestern United States contain small amounts of uranium.1

Jan 1, 1982

By V. K. Srivastava, T. Gupta, T. Ghosh

"In recent years, the demand for rare earth elements (REEs) has grown due to increasing demand and global supply shortage. The supply deficit of these critical elements has encouraged the search for new sources, with coal and coal byproducts as possibilities. Coals from certain parts of the world can be rich in REEs and can approach a total concentration of 1,000 ppm. Two Alaskan coal samples, from Healy and Wishbone Hill, were investigated for the effects of density and particle size on REE concentrations for three selected size fractions, and flotation tests were conducted on finer fractions. Additionally, bottom ash and fly ash samples from a power plant were examined for their REE concentrations. The results show that the upgrade potential for REEs on an ash basis from a whole-coal basis ranges from 2:1 for the Wishbone Hill samples to 4:1 for the Healy coal samples. Flotations of the finer fractions of the two coal samples, conducted under similar conditions, revealed higher concentrations of REEs in the tailings. Both coal samples had comparatively higher contents of light-group rare earth elements (LREEs) than heavy-group rare earth elements (HREEs). REE content trends for the power-plant products on an ash basis indicate that fly ash has slightly higher concentrations of both LREEs and HREEs than bottom ash. IntroductionRare earth elements (REEs), also known as rare earth metals, and their compounds are vital components in industrial, automotive, petrochemical, defense and medical applications. Dysprosium in combination with other elements is used in laser materials and nuclear control applications. Neodymium is present in magnets that are used in the manufacture of wind turbines and hybrid cars. Europium, terbium and yttrium are used in devices that have visual displays such as computer screens and laptops (Haxel, Hedrick and Greta, 2002; Bunzli, 2013). REEs pose fewer environmental problems of disposal and recycling than their conventional heavy metal counterparts (Haxel, Hedrick and Greta, 2002). They are key materials for radar systems, avionics, modern national defense and satellites (Cammarata and Sieradzki, 1994; Hedrick, 2010; Martin, 2010; Szumigala and Werdon, 2011; Cordier, 2011; Bunzli, 2013). REEs are often classified into light-group rare earth elements (LREEs) and heavy-group rare earth elements (HREEs). This classification is primarily based on the electronic configuration in the outermost shell. LREEs, ranging from lanthanum to gadolinium, have a single or no spinning electron in the outermost 4f shell while HREEs, ranging from terbium to lutetium, have paired electrons in the 4f shell. This difference in electronic configuration is responsible for the differences in physical and chemical properties of REEs."

Jan 1, 2017

Conventional wisdom in the mineral processing industry leads one to believe that pressure oxidation of refractory carbonaceous (preg-robbing) ores is not a practical approach to process development. Initial acid pressure oxidation testing on carbonaceous sulfide ores at the Twin Creeks Mine supported this conventional wisdom. After testing other refractory process options, including air and oxygen enriched roasting, Santa Fe Pacific Gold decided to take a second look at pressure oxidation, using conditions outside the normal range of conventional practice. A combination of very fine grinding and high operating temperature and pressure resulted in significant increases in gold extraction. This paper details the effect of operating parameters developed for Twin Creeks on gold recovery, sulfur oxidation, carbon oxidation/passivation and preg-robb through the laboratory and pilot plant investigations.

Jan 1, 1995

By Jodi Banta

Thanks to strong industry support and longstanding partnerships, the University of Arizona has provided extensive pre-college mining education and outreach for more than a decade. These efforts to promote mining-related degree programs and the wide variety of indemand career opportunities reach thousands of middle and high school students and hundreds of teachers every year. The School of Mining Engineering & Mineral Resources is constantly looking at ways to help students overcome barriers into degree programs. But competition among degree programs for talent is fierce, and outreach has not made a big enough difference in the number of students pursuing mining engineering degrees. With workforce shortages threatening to undermine the industry, more is needed. The Bureau of Labor Statistics estimates 500 new mining engineering jobs each year, and according to a study by Deloitte (2023) nearly 50 percent of skilled engineers will reach retirement age in the next decade. At the same time, the 14 accredited mining or mineral engineering degree programs in the United States are producing fewer than 200 graduates annually (Society of Mining Professors and Society for Mining, Metallurgy & Exploration, 2021). To better understand mining’s competitive position, the School of Mining Engineering & Mineral Resources conducted a comprehensive study to determine (1) how prospective college students, parents and educators perceive the industry, related careers and the mining engineering degree, (2) factors affecting students’ choices of degrees and career plans and (3) the roles parents and educators play and how they influence students. This article is the first of two installments to discuss the results. This installment focuses on what students, parents and educators think about mining and where they get those impressions, as well as the role parents and educators play in influencing students’ choices of careers and degrees. The second installment, scheduled for publication in a later issue of Mining Engineering, looks at what students are seeking in their degrees and careers, and how mining compares with other degrees and industries.

Sep 1, 2025

By A. Noble

For the past 30 years, process flowsheet design has been accomplished largely through modeling and simulation. This approach provides circuit designers the freedom to test various separation approaches while minimizing physical and human resource requirements. The Limn® software provides a unique approach to process simulation, through a Microsoft Excel interface. While the software comes with standard process models for numerous unit operations, the Excel calculation environment and the accompanying VBA platform provide a convenient interface for custom model integration, even for non-experienced programmers. This feature is especially useful for university students in introductory process modeling and simulation-assisted flowsheet design courses as well as experienced practitioners with proprietary process models. This paper shows how the Limn® software may be used to solve basic process engineering problems as well as more comprehensive circuit design challenges. Industrial examples as well as opportunities for training and education are presented.

Feb 23, 2014

By L. G. Hagenbuch

Several factors need to come together in creating an integrate mining equipment dispatching system. At the hub of these factors ace the central dispatching formulas. This paper details the development of these central dispatching formulas and explores the combining of these formulas with other elements to create an integrated dispatching decision. WHY DISPATCHING? Truck dispatching implies and in reality should equate to mine equipment efficiency. Good truck dispatching will yield good mine equipment efficiency while poor truck dispatching will yield the alternative. Truck dispatching can either be automated through a computerized, process or it can be manual. Every mine with haul trucks has a truck dispatching system whether it is recognized or not. Even a system wherein the hauler operators determine where they are going for their next load is a truck dispatching system.

Jan 1, 1987

By Andrew J. Petruska, Rik Banerjee

This study explores implementing a machine learningbased system to generate a 3D surface repre- sentation of the roof and support straps in the mine. Event cameras have been chosen for their performance in high-dynamic-range lighting conditions and for their low latency. To enable automated drilling and bolting, 3D vision using eventbased cameras has been developed. A ground-truth set is created using two, time-synced event cameras and a LiDAR camera. These sensors are used to construct a ground-truth dataset of corresponding event- camera images and surface maps from the LiDAR. The network is tested with stereopairs of event images and produces a depth image with ±5 mm RMS error on average across 1000 test images.

Feb 1, 2024

By Steve Kral

"Repairing and replacing the nation’s aging and crumbling infrastructure has become a major issue with the American public. It is no secret that the upkeep of roads, tunnels, bridges, and water and waste water facilities has been neglected for decades. Cities, states and towns across the United States are now grappling with these issues, ones that will take decades and billions of dollars to fix.Because of this infrastructure issue, the North American tunneling industry is flourishing. Cities across the country are looking to go underground to alleviate traffic issues, transporting water and waste water to more people in more efficient ways.In October, the seventh annual Cutting Edge conference was held in Atlanta, GA. Put on by the Underground Construction Association of SME and Britain’s Tunnelling Journal, about 175 tunneling and underground construction professionals from around the world attended. Attendees included owners, designers and contractors. An accompanying exhibit included 28 companies.The theme of the two-day conference was Advances in Tunneling Technology. Speakers examined the latest advances in tunneling technology, its methodology and how these advances can be harnessed to assist upcoming major tunneling projects. The conference featured a tailored, high-end, single-track program of subject-specific presentations that focused on innovation and practical experience. Two in-depth panel discussions at the end of each day were also included.Patricia Mulroy was a keynote speaker on Monday. She is senior fellow for climate adaptation and environmental policy at The Brookings Institution. Like many others, Mulroy believes the U.S. infrastructure in in a state of disrepair. But, she said, no one wants to talk about it. “We need to have a conversation about infrastructure. We cannot be afraid to talk about building it and the cost.” For this to happen, though, the nation needs leadership."

Dec 1, 2018

By Shinzaburo Kato

In 1977 Kawasaki Steel Corporation (KSC) built No. 6 BF (Blast Furnace) with an inner volume of 4 500m3 as part of our program to produce 8.5 million tons of crude steel a year at Chiba Works. As the primary raw material to be used in No. 6 BF, we decided to use sintered ore, because we were confident in the obvious advantages of our technology developed by that time on sintering and BF operation using sintered ore. At Chiba Works, however, we had no space for the construction of a sinter plant, so we decided to build it abroad. Sintered ore is easily crushed and degradated. Producing sintered ore at a point far away from the blast furnace and transporting it across the ocean was the world's first attempt. To successfully realize it, we conducted a series of fundamental surveys and studies with special stress on the real aspects of degradation of sintered ore caused by long-distance transportation and handling and the ways and means to prevent the degradation. As a result, we decided to build a plant on the Mindanao of the Philippines.

Jan 1, 1982

Lignite is a kind of easy-to-slime and low rank coal. It is hard to be separated by the conventional wet coal beneficiation technologies. Meanwhile, in recent decades, a large amount of fine coal (-6 mm) is generated as the mechanized mining technology has been progressively deployed in coal sector, which causes a great difficult for lignite beneficiation and upgrading due to lack of efficient technology available. In this paper, a vibrated gas-fluidized bed was used to separate the -6 mm fine lignite particles. Separation experiments of -6+3 mm and -3+1 mm lignite were carried out in a laboratory-scale vibrated gas-fluidized bed. The effects of several parameters including the superficial air velocity, vibration intensity, bed height and exterior moisture content on the separation performance were experimentally studied. The results show that the optimal separation performance was achieved when the superficial air velocity is 0.3, the vibration intensity is 1.4, the bed height is 50 mm, the exterior moisture content is below 4% (-6+3 mm) and 2% (-3+1 mm). And the probably error E values of -6+3 mm and -3+1 mm size fraction of lignite are 0.202 and 0.225 respectively. The results indicate that a vibrated gas-fluidized bed can provide an effective solution for -6 mm lignite separation.

Feb 23, 2014