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By Richard Kojo Gabah

Western mining companies are entering an African critical minerals market where access is harder to secure, risk is being priced more sharply, and execution advantages are increasingly decisive. The continent holds significant reserves and production potential of cobalt, lithium, copper, graphite, manganese and rare earths critical to the energy transition, yet Chinese-aligned capital has built a structural edge in access and execution speed. Simply signing narrow offtake agreements to buy output is no longer sufficient. Western firms win when they convert quality orebodies into bankable projects by reducing aboveground risk faster than competitors through integrated infrastructure access, durable fiscal alignment, and credible local value creation. Western mining companies will break into Africa by pairing capital with partnership, building corridors enabling infrastructure and power, designing credible value addition pathways and operating in a way that is politically durable through transparency, community benefit and fiscal terms that share upside in commodity upcycles. This feature article offers a practical playbook for mining executives and investors. The core argument is straightforward. Winning in Africa requires competing on the full system around the mine. Corridors and power, processing pathways, contract durability, community benefit and regulatory execution are now decisive variables in project valuation and capital access.

Mar 1, 2026

By D. L. Watson

In spite of the deflationary state of the minerals business today, there will be opportunities for those who can fulfill future needs. Since there are abundant supplies of ores and fuels to keep prices down, at least in peacetime scenarios, future needs may be as much political and social as technical and economic. Engineers and economists will develop new and innovative ways to find, mine, process and pay for mineral deposits. Pressure from governments and non-governmental organizations and the public will combine with market forces to provide opportunities for highly competitive, risk-taking enterprises who can leverage the qualities of their orebodies and employees by being good neighbors and partners.

Jan 1, 2000

By Tim O’Neil

Until about three years ago, Asarco's copper business consisted predomi¬nantly of custom smelting of ores and concentrates produced by other mining companies. Since then, the company has been transforming itself into a fully integrated producer in copper mining, smelting, and refining. In doing this, Asarco has lowered its costs and restructured its operations and finances. Now, Asarco hopes to complete this process by spending $260 million over the next three years, to expand and modernize its copper facilities and boost production by some 40%. The capital spending program includes: • $130 million at the Ray mine about 113 km (70 miles) north of Tucson, AZ, to expand mining capacity and install an in-pit ore crusher, mill, and concentrator; • $100 million, to expand the mining capacity at the Mission Complex located south of Tucson, AZ, and refurbish the adjacent, idle Pima mill and concentrator. (Asarco had earlier exercised an option to purchase the Pima mill for about $6 million); and • $30 million, to modernize the copper smelter in El Paso, TX, with a new flash smelting process. The new program is in addition to a recently completed first-phase expansion of the Mission mine, mill, and concentrator. This $13 million debottlenecking of existing operations in¬creased production capacity by 46% or 24.5 kt/a (27,000 stpy), to 79 kt/a (87,000 stpy) of copper in concentrates. In addition, a previously an¬nounced $12 million expansion program at the Ray mine is scheduled for completion in early 1990. It will expand mill capacity, to offset the anticipated effects of increasing ore hardness as the pit deepens. Ray produces 68 kt/a (75,000 stpy) of copper in concen¬trates and an additional 36 kt/a (40,000 stpy) of electrowon copper. By 1992, when Asarco's expanded and modernized copper facilities are operating at capacity, the company's mine output will have increased by 67 kt/a (74,000 stpy), to 263 kt/a (290,000 stpy) of contained copper. That will be enough to provide all of the feed required for Asarco's two copper smelters - by then, both of them modern, state-of-the-art facilities. Asarco's expansion and modernization program will further reduce costs and provide added assurance that the company's copper business will be profitable at the bottom of the cycle, according to Chairman Richard de J. Osborne The Ray mine portion of the new program will include construction at the mine of a new mill and concentrator, with a capacity of 18 kt/d (20,000 stpd) of ore. These new semiautogenous grinding mills and large capacity flotation cells will augment the present 27.2 kt/d (30,000 stpd) concentrator located 29 km (18 miles) away, in Hayden, AZ. A 29 km (18 mile) pipeline will be built to carry tailings in slurry form from the new Ray mill to the present tailings pond. Concentrates from the new facility will be shipped by rail to Asarco's Hayden copper smelter. Ray's present 27.2 kt/d (30,000 stpd) crusher, adjacent to the open-pit, will be replaced by a 54.4 kt/d (60,000 stpd), portable in-pit crusher and conveying system. This will reduce the more expensive ore haulage by truck. The Ray project is scheduled for completion by 1992. It will increase the mine's annual output of copper in concentrates by an additional 33.5 kt/a (37,000 st), to 102 kt (112,000 st). And the project could mean an additional 400 jobs at the 730 employee Ray operation. Work at the Mission Complex involves reactivation of the Pima mill and concentrator and expansion of mine output sufficient to provide ore to both the Pima mill and the present Mission mill. In 1985, Asarco purchased the Pima mine, which occupies one end of the Mission pit. The work at Mission will increase its annual capacity by 33.5 kt (37,000 st), to 112 kt/a (124,000 st) of contained

Jan 1, 1989

By A. Pavlidis

This paper investigates variations of lignite quality attributes with geostatistical methods. The study focuses on lignite from the Southern Field in the Greek province of West Macedonia. The targeted quality variable is the ash water-free content (AWF). A geostatistical model is constructed based on data from 480 drillholes (approximate drill hole spacing of 250m). For each drillhole, the vertical average of the AWF is calculated. The coarse-grained AWF is then modeled as the superposition of a trend surface and fluctuations. The spatial dependence of the fluctuations is modeled by means of the experimental variogram. Kriging estimators are used to determine the AWF values on a rectangular grid, and the uncertainty of the estimates is calculated. Implications of the analysis for the variability of the produced lignite are discussed, and recommendations for additional drilling are proposed.

Jan 1, 2006

"The 35th Annual American Mining Hall of Fame Awards Banquet and Fundraiser, sponsored by the Mining Foundation of the Southwest (MFSW), will be held at the JW Marriott Tucson Starr Pass Resort & Spa on Saturday, Dec. 2, 2017. This year, the Foundation will honor one living Hall of Fame inductee, two Medal of Merit recipients, four honorees from Mining’s Past and an Industry Partner for their respective contributions to the mining industry.Gary J. Goldberg will be the 2017 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Goldberg was appointed president and chief executive officer and joined the board of directors of Newmont Mining Corp. in March 2013. Prior to this appointment, he served numerous companies in key positions including Rio Tinto Minerals, US Borax and Coal & Allied Industries. At every appointment, he was able to improve safety concerns and reduce injury rates. While serving as chairman of the National Mining Association, Goldberg launched the CORESafety initiative and US Borax was the first mining company to receive the California Governor’s Environmental and Economic Award.The Medal of Merit will be awarded to John C. Lacy, a shareholder of DeConcini McDonald Yetwin & Lacy, P.C. and a director of the Global Law Center at the University of Arizona’s Law School. Lacy’s law practice concentrates on mining and public land law and encompasses transactional and title consideration involving acquisition of mineral rights. He played a crucial role in the revisions to the mining law of the Republic of Bolivia and the English translation of the mining laws and regulations of Mexico. Lacy’s expertise in mining law impelled the University of Arizona James E. Rogers College of Law to approach him to head the new Global Mining Law Center in 2015. The program now partners with the Lowell Institute for Mineral Resources and offers cross-listing of courses"

Jan 10, 2017

By N. B. Prenn

Many recent projects have been developed and mined based upon imaginary reserves. Imaginary or "geo-fantasy" reserves have cost many companies millions of dollars. The significant and varied technological advances in the mining arena have done little to curb reserve calculation problems. These advances may have served to increase the prevalence of reserve problems by putting more tools in the hands of personnel not properly trained or experienced in reserve estimation. This paper will discuss potential problems related to calculating reserves, which include: SAMPLING ERRORS -obtaining a representative sample. -Decay analysis of wet RC drilling -Bias introduced by sample preparation. -Assay bias; Coarse gold. -Specific gravity samples. GEOLOGICAL ERRORS -structural boundary definition. -Separation of high grade and low grade zones. -Incorrect continuity assumptions MODELING ERRORS -Too much influence of high grade samples. -Improper method of calculation. -Assumed range of influence. -Errors in the data. ENGINEERING ERRORS -Inaccurate assumptions. -Inadequate metallurgical testing. -Designed bottlenecks.

Jan 1, 1992

By L. Xia, B. Hart, V. Sidorkiewicz

Sodium silicate(s), also known as “water glass”, are one of the oldest and most widely used industrial chemicals. Its first use in North American mining operations can be traced back to around 1925, which coincided with early use of xanthates in mineral flotation. Silicate functions as a sulphide and non-sulphide gangue mineral dispersant, depressant and modifying reagent in grinding and flotation operations. It is believed that soluble sodium silicate promotes selectivity of value added sulphides against gangue minerals, resulting in both grade and recovery improvement. This paper seeks to link improved grade/recovery to the interaction characteristics of minerals and the sodium silicate. A systematic study was performed with individual mineral species, an artificially designed model ore and the feed ore from a copper metallurgical operation. The function of sodium silicate was evaluated in the context of colloidal chemistry and linked to mineral surface chemistry. Measurement of pulp rheology and mineral zeta potential identified that sodium silicate works as a dispersant. The dispersion is accomplished by increasing a mineral’s net surface charge, resulting in a mineral variable change in viscosity. Bench scale laboratory flotation tests suggest that better dispersion leads to a diminished interaction of chalcopyrite with gangue. The improved Cu grade and recovery then are likely in response to an increased accessibility to collector along with a linked increase in particle bubble attachment resulting in better separation efficiency. ToF-SIMS surface chemical analysis of the flotation samples found a higher proportion of sodium silicate on minerals from the flotation tailings relative to the concentrates. Moreover, attachment of sodium silicate appears to be mineral specific; the data indicates that sodium silicate favours the surface of gangue phases over the value sulphides. INTRODUCTION Mineral processing involves enrichment of valuable minerals from an ore, where the separation process utilizes differences between the properties of the value-added and gangue minerals. The properties of minerals, for example composition, specific gravity, particle size, magnetic properties etc., in any flotation feed ore, can vary significantly between the various minerals present. In flotation seperation surface chemistry and wettability is a significant component promoting selective separation of the various mineral phases [1,2] Mineral surface wettability can be changed, advantageously or deleteriously, by many factors including: surface layer alteration through oxidation; galvanic interactions; attachment of secondary precipitates; the adsorption of various reagents [3] In the flotation context the wettability of a minerals surface can be manipulated by various reagents. Collector reagents may selectively attach to specific minerals in the mineral/water slurry enhancing their surface hydrophobicity, increasing bubble-attachment efficiency and improve flotation kinetics and mineral recovery [4]. In contrast, depressant reagents may selectively reduce a minerals surface hydrophobicity resulting in poor particle-bubble attachment and non flotation. In essence, a mineral flotation flow sheet is designed to induce/promote a hydrophobic surface to the value mineral and a hydrophilic surface to all others. Therefore, the versatility of the froth flotation process lies in the selection of different flotation reagents.

Jan 1, 2019

By VIVEK KASHYAP, PATRICK TAYLOR

The presence of iron in sphalerite induces the formation of zinc ferrite (ZF) during roasting. Zinc refinery residues (ZRR) and electric arc furnace dust (EAFD) contain a significant amount of zinc ferrite and are difficult to treat. According to the literature, up to 71% ZF has been found to be present in ZRR. The dissolution of zinc ferrite is inefficient even in aqua regia. The Waelz process is an existing process to recover zinc from electric arc furnace dust by reduction using carbon monoxide followed by the volatilization of zinc. In this study, zinc was selectively extracted from zinc ferrite by partial reduction of zinc ferrite at relatively low temperature followed by leaching in dilute sulfuric acid (20 g/L). Pure zinc ferrite samples were partially reduced to zinc oxide and magnetite by using H2 gas as a reductant. The presence of magnetite and zinc oxide was confirmed by X-ray diffraction (XRD) technique. A maximum of 95%zinc extraction was achieved after leaching with sulfuric acid on the reacted samples. The paper also discusses the effect of time, temperature, and concentration of H2 in the reducing gas on the extraction of zinc and iron from ZF.

Sep 16, 2020

By CAIJUN CHEN, MING ZHANG, ZHENWEI WU, FENG ZHOU, BOQUAN LI, XILIANG ZHANG, ZHOU PU

Traveling grate is a widely used process for iron ore pellet production; however, the thermal state of pellets in drying section is still unclear. In this study, the temperature distribution of drying section was investigated using computational fluid dynamics (CFD). Based on the calculated results of airflow velocity, space temperature distribution, and the temperature change of pellets, it concluded that there is a coupling effect in drying section in traveling grate. The gas with higher temperature in DDD transfers heat to UDD through the gap of the insulation board, and the temperature gradient of the pellet bed changed before reaching the insulation board. The characteristics of pellet bed expected to appear in DDD was displayed in UDD in advance. Moreover, a contrast experiment was conducted to verify the model.

Feb 1, 2021

By CHENGLONG XU, HAORAN LI, YALI FENG, JINRONG JU, Shunliang Liu

With the depletion of mineral resources and the growing demand for metal resources from industrial development, the recovery of metal resources from secondary resources has attracted increased attention. Among all secondary resources, spent catalyst is one of the most important as it contains valuable metals such as vanadium, nickel, molybdenum, cobalt, and aluminum. Compared with the extraction of metals from minerals, the recovery of valuable metals from spent catalysts has the advantages of a simple process, a short production cycle, lower investment cost, and less environmental impact.

Apr 1, 2023

A group of geologists is located in a remote area of North America, without telephone lines, electricity or even running water. They have spent days accumulating data for a mining company that is eager to receive any information about the dig. But the team does not have access to a wired communications infrastructure. So the geologists must wait until they get to the nearest town to transmit their data. TMI Communications has a mobile satellite communication system that allows geologists in the field to transmit their data from remote locations. The company's satellite is the heart of its North American mobile communications network. This satellite turns all of North America, including Canada, Mexico and the Caribbean into a single digital communications cell. Traditional terrestrial communications systems, such as dedicated phone lines or cellular systems, cannot handle a remote geological exploration camp's extensive communications needs. Cellular technology, where available, has high costs and limited applications. For geologists in the isolated areas of North America, accessible and reliable phone service is vital to success. For those who have established temporary camps, TMI Communications' satellite phone service has improved the speed and accuracy of their communications with home base. This wireless network is suited to meet the needs of existing data applications and the challenges of new ones. It can support any one- or two-way, fixed or mobile data transfer. TMI's network enables geologists to transmit exploration results, spreadsheet information and location co- ordinates to anywhere in the world, at any time. This is important if a team needs to relay vital data back to its headquarters to support immediate decision making on a prospect site or a find.

Jan 1, 1999

By Thomas P. Meloy

The understanding, quantification and use of locked particles. Specifically discussed is the use of Textural Transforms (Meloy, 1991) for the implementation of the Interfacial Area Conservation hypothesis (Meloy, 1984); the quantification of the locked particles as a function of fragment to inclusion size ratio; and the selection of set points.

Jan 1, 1991

By Douglas N. Kendall

There are three definite steps in the making of a mining industry in any country. These are as follows: Step A - Geological Mapping This step covers the basic geological mapping of the country at scales of 1/250, 000 up to l/50, 000. This step eliminates territory and directs the exploration teams to the areas of potential interest. Step B Prospecting This step includes all phases from detailed geology through geophysics and drilling up to the point of proving that an economic ore body exists. Step C - Mine Development This is the expensive step, involving the creation of the mine, including shaft-sinking, ore treatment plant, etc.

Jan 1, 1963

By A. Gungor

Thermal treatment can significantly improve industrial comminution operations by reducing energy requirements and increasing mineral liberation. The assistance of thermal pretreatment prior to grinding by microwave heating is scrutinized in this study. For this purpose three copper ore samples with different chemical composition were used. To see the effect of microwave heating on ore; work index, breakage rate and breakage distribution functions of original and heat treated samples were examined. The results obtained in this study did not show significant improvement in the grindability characteristics of the studied ores with microwave heat treatment. The inadequate amount of microwave transparent matrix was the main reason for the absence of cracks and micro-fractures in the microwave heated copper samples.

Jan 1, 1999

By J. W. Mausteller

Chemical oxygen supplies have been used for nearly 60 years, with their greatest application during the last 25 years. They are of two types, the superoxides and chlorate "candles", The superoxides are demand chemicals, responding to the needs of the user and to supply oxygen and remove carbon dioxide. Chlorate candles are formed solid element which furnish oxygen only and do not remove carbon dioxide. Properties of these materials will be described, with comments on the respiratory requirements of a man under various workloads, types of equipment which use chemical oxygen, comparison with other systems and potential application to an underground mine survival system.

Jan 1, 1971

By STEVEN J. SCHATZEL, Zoheir Khademian, KAYODE M. AJAYI

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine, creating safety concerns. To provide recommendations for developing guidelines that ensure a safe coexistence of longwall mining and unconventional shale gas production, this study uses a discrete fracture network (DFN) model to evaluate the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations are within values validated with field measurements.

Mar 1, 2023

By Jacob L. Mathis, Todd Tharpe, Jonathan Steflik, R. M. True

In June 2022, Louisville MSD completed a 6.5 km (4-mile), 6.1 m (20-foot) finisheddiameter CSO conveyance and storage tunnel system located along the Ohio River in downtown Louisville, Kentucky. During construction, the Ohio River Tunnel alignment was expanded 2.4 km (1.5 miles) into areas where natural gas was detected. Without delaying construction, the project team developed and implemented a natural gas risk mitigation strategy to safely excavate the tunnel via TBM and install concrete lining. The risk mitigation strategy included the installation of gas-vent borings, increased tunnel ventilation, retrofitting tunneling equipment for “gassy” operations, and modifying the project specific HASP.

Jun 13, 2023

By A. K. Bakshi

An on-line rheometer, suitable for use with slurries, has been developed at Michigan Technological University. This rheometer can be used with both Newtonian and non-Newtonian slurries, and produces complete shear-rate/shear stress curves which characterize the time-independent rheology of the slurry. The sensor utilizes the Hagen-Poiseuille equation and Boyle's Law to calculate the shear rate, slurry flowrate, and shear stress from a series of pressure measurements. The design of the unit allows the measurement sample to be continuously collected from operating process streams in the often-hostile on-line environment. The shear rate/shear stress curves can be used to conveniently calculate the apparent viscosity at any given shear rate, and also to measure any yield stress or other deviations from Newtonian behavior.

Jan 1, 1999

By Suresh K. Bhatt

Appalachian coalfields have been the predominant source of quality coals since the inception of commercial mining in the United States. In a broad sense, Appalachian coalfields can be considered those east of the Mississippi River, representing about 55% of total US coal production. In this special feature on Appalachia in MINING ENGINEERING, emphasis is given to the four coal-producing states of Pennsylvania, West Virginia, Virginia and (eastern) Kentucky. These four states produce more than 90% of the coal from the total Appalachian region, or about 40% of the total US coal production. Historically, Appalachia has been the principal source of coal for domestic industries and for export. There have been numerous fluctuations in the Appalachian coal industry during the past 20 years. Appalachia was affected by cyclical and structural changes in various industries, particularly the US steel industry, and changing world coal markets. It was also the region of more mine worker labor stoppages than other parts of the country. In general, the factors that affected Appalachian coal production over time are identical to those that determined changes in coal production nationally.

Jan 1, 1995

By I. A. Kunasz

This paper is not intended to review and re-state general information on lithium, but rather to analyze the paradigm that has caused such a rapid rise in lithium production and the development of new lithium producing centers. Details on pegmatites, brines, concentrate and chemicals are amply covered in a number of publications ? SME?s Industrial Minerals and Rocks, Industrial Minerals, Roskill and a host of other publications. There is no question that the latest interest in lithium has been driven by the potential development of the electric car. This stimulus prompts one to recall two symposia: 1. ?Lithium Resources and Requirements be the year 2000?, organized in 1976 by the U.S.G.S. in Denver (1) and the sequel 2. ?Lithium ? Needs and Resources? at Corning, N.Y. (2).

Jan 1, 2011