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By Andrew C. Katen

The mining industry faces increasing geopolitical risk in the coming decades. Constraints such as resource nationalism, corruption and social license could grow to outweigh fundamental limitations like geology or supply and demand (Ernst & Young, 2013; Verrastro et al. 2010). Lurking beneath these more immediate and palpable concerns, however, may be more significant risks entrenched in geography and history. Deep-rooted cultural and strategic forces that emerge slowly ? or erupt suddenly and unexpectedly ? can generate momentous and far-reaching political, social and economic changes. While multinational enterprises routinely assess for political risk, the nature of minerals extraction means long-term and systemic geopolitical conditions are especially important for mining companies to identify and understand. Mine development is a decades-long process that binds companies to the land and makes changing course to avert emerging threats a difficult and costly option. Consequently, geopolitical assessment is a pertinent and valuable tool that mining companies can use to more comprehensively evaluate strategic threats and opportunities. Geopolitics is the study of society, politics and strategy through the lens of geography (Gray, 1996). Its emphasis on relatively permanent physical features of the earth makes geopolitics a uniquely valuable tool for assessing political risk. Topography, climate and natural resources have shaped, constrained and motivated peoples and governments throughout history. These influences transcend regimes, policies and borders ? and even states themselves ? which, by contrast, change often and dramatically. Framing politics against mountains, deserts and rivers supports identification of historical patterns and forecasts of emerging trends. In other words, the physical map provides an objective and consistent model for studying a subjective and dynamic subject such as politics (Sloan and Gray, 1999). Consequently, geopolitical assessment can highlight threats and opportunities that go unaddressed by other risk methodologies that emphasize current conditions (Glancy, 2012). Taken together, the permanence of geography, hindsight afforded by centuries of political history, and interconnectedness of world events makes geopolitical assessment a valuable approach for conceptualizing strategic risk.

Mar 1, 2014

By A. W. Hamilton

If you don't know a gauss from a grasshopper, you may be better off than you, think, particularly if you're an ore dressing engineer charged with the responsibility of selecting magnetic equipment for minerals separation and beneficiation. Gauss is a unit of measure for a magnetic field. It indicates the number of imaginary lines of force per square centimeter or per square inch radiating from a magnet. In discussing the strength characteristics of a magnet, we have come to speak of a magnetic field of 800 gauss, for example, meaning 800 lines of force per square centimeter. Gauss became the standard for selecting drum type separators many years ago under an arbitrary set of circumstances. The standard has continued to this day even though magnetics applications engineers have long considered it inadequate. The configurations of the older gauss meter were such that the most accurate and convenient readings on a drum type separator could be made at distances greater than one inch. So, an arbitrary distance of two inches was established and that two inches became the standard. Since then, it has become commonplace to specify magnetic strengths for drum separators according to average gauss readings at two inches; for example 500 gauss average at two inches, 750 gauss average at two inches and so on, even though gauss readings at two inches have much less to do with the separating and beneficiating function of a given application than was formerly believed. The standard was adopted as a means of gauging the strengths of electromagnetic drum type separators, for they were the only ones around at the time. These machines were usually designed with no magnetic considerations other than that the material to be separated should be agitated vigorously and the magnetic fields should be deep and strong. Drums built this way performed well enough, so it seemed logical to measure their magnetic strengths. Hence, gauss at two inches. Now, new improvements in magnetic techniques have made average gauss measurements at 2 inches positively obsolete.

Jan 1, 1971

By D. R. McMullin

The purpose of this paper is to provide a method for mine planners and engineers to evaluate on a conceptual basis if a shaft or a ramp is most suited for their particular underground access requirements. Mine planners and engineers are often raced with the decision of choosing which method of underground access is best suited for their particular requirement. Underground access can be provided by a shaft, ramp, adit, or slope for either exploration and/or actual production operations. This paper will focus on the construction cost and schedule differences between sinking a shaft and excavating a ramp which are currently the most typical access alternatives used in the western United States. It would be wrong to state that one method is superior to the other in every case. There are many variables to be addressed, and the degree of sensitivity of each of them will eventually dictate which method is the most suited to the particular circumstances. This paper compares the construction cost and schedule or sinking a shaft to excavating a ramp at different depths given different ground and hydrological conditions. This comparison provides mine planners with "rules or thumb" that may be applied to the access selection process.

Jan 1, 1994

By E. Craig Simmons

Uranium is an element incompatible with respect to the major rock-forming minerals crystallizing from granitic magma, entering in- stead trace minerals such as zircon. The relationship between the saturation limit (SL) for such a mineral and the bulk distribution coefficient (Do) for U is central to understanding the distribution of U and its availability to late- stage fluids which can form ore deposits directly, or labile U which can be remobilized later. Low SL values imply early crystallization of zircon, but in very small proportions, minimizing Do and maximizing the degree of enrichment of U in late-stage fluids. Thus, granitic rocks with low Zr contents (due to a low saturation limit for zircon) are most likely to evolve U- enriched differentiates; this will be reflected in a high U content of the zircons (but not necessarily high U abundances in whole-rocks). Thus, the ratio of the U content of zircon to the Zr content of the corresponding whole-rock is potentially a very useful parameter in identifying granitic rocks which are most likely to have U-enriched solutions associated with them. The granitic rocks associated with the U deposits of the Midnite Mine area, Washington, have geochemical characteristics which fit very well the model presented here. The rocks are very low in Zr (100 ppm) and contain zircons with extremely high U contents (3,000-4,000 ppm).

Jan 1, 1981

By Kermit Allen

Storing natural gas in solution mined salt cavities appears to be one of the more promising methods being considered by some major gas transmission companies for meeting peak demands. Historically, these companies have been faced with the problem of meeting peak demands when the source of natural gas is located hundreds of miles from the marketing area. Transcontinental Gas Pipe Line Corporation's position was further complicated because some of its offshore Gulf Coast gas supply wells may have to be shut in during hurricane alerts. Transco's solution was to construct. solution mined salt storage caverns adjacent to its pipeline near Eminence, Mississippi. (See Figure 1.) In 1965, Fenix & Scisson, Inc., was engaged by Transco to evaluate the feasibility of storing natural gas in caverns dissolved from salt at selected locations along Transco's pipeline to the East Coast. In June of that year a report was submitted to Transco concluding that this proposal was feasible and recommending several potential sites for storage development. Additional engineering and geological studies followed and in March 1968 the Eminence Salt Dome site was selected and storage construction began that year.

Jan 1, 1971

By Aliakbar Golshani, Behnam Eslami

"Surface settlement adjacent to sensitive structures is a challenging issue in the tunnel engineering. In this study, 3D simulation of TBM excavation has been performed with the FLAC3D code and then the results compared with real monitoring data. Sensitivity analysis was carried out for all parameters affecting the surface settlement, such as the tail void grouting pressure (Pt), the face pressure (Pf), the tunnel diameter (D), overburden (q), shield thickness (t) and the length of the shield (L). The results show that the face pressure, tail void grouting and tunnel diameter have a considerable effect on the maximum ground displacement.In this paper, the monitoring data from Mashhad Metro was used to verify the numerical simulation. Data monitoring for about 47 sections between A2 and D2 stations was selected and a multiple regression analysis was performed. Based on this analysis, an empirical relationship was obtained for the coefficient of regression relationship which confirmed the sensitivity analysis.INTRODUCTIONThe surface settlement due to tunnel excavation is a complex issue, since the surface displacement is a function of several parameters that they are related to the excavation method, soil characteristics and TBM elements. Prediction of deformation is a very important issue, especially in urban areas, since these displacements may be affected the superficial structures. In recent studies, one of the most popular empirical relationships that is used to predict the surface displacement has gussian curve that it was suggested by Peck [1, 2]. An analytical relationship was proposed by Chow that its base assume was isotropic of soil, that surface settlement can be estimated based on the tunnel geometry and the shear modulus(G) [3]. Besides these methods numerical approaches such as the Finite Element Method (FEM) and the Finite Difference Method (FDM) have been used over the last twenty years, since numerical modeling has a high capability to simulation a complex soil conditions and irregular geometry [4]. In this study, all aspects of the EPB-TBM on Mashad Metro Line 2 were modeled and the most important influences on surface displacement in urban areas were determined [1, 3]."

Jan 1, 2016

By Son Hoang Nguyen, Thanh‑Hai Pham, Duoc Van Tran, Dung Thi Kim Nhu

Apatite ore plays a critical and irreplaceable role in fertilizer production and is being upgraded in quality in northern Vietnam. The old tailing of the Bac Nhac Son beneficiation plant (Vietnam) has a significant apatite amount in the form of coarse unliberated particles. These millions of tons of tailing ore have 6–8% of P2O5 content, which can be retreated to provide fertilizer factories. This work presents the results obtained in recovering apatite from this tailing in the laboratory. By the combination of the processes of classification, preliminary flotation, re-grinding and cleaning in the flotation column, an apatite concentrate of 30.68% P2O5 can be obtained with the total recovery of 37.76% from the initial tailing of 7.56% P2O5. The study results not only provide an appropriate technical solution for recovering the apatite ore from tailing ore but also have outstanding meaningness in the recovery of mineral resources under the context of a circular economy.

May 24, 2023

By A. Duerksen

"Surface coal mining in West Virginia has supplied energy to the eastern coast of the United States for over a century. Over the years, the coal mining industry has been forced to adapt as societal demands regarding health, safety, and environmental impacts have changed. More recent pressure has called for another iteration of change: long-term post-mining sustainability. The research discussed in this paper investigates one potential solution - or component of a solution - to improve the sustainability of surface coal mining in West Virginia: post-mining wind power. The paper begins with an introduction to the Appalachian region of the U.S. and the role that mining has played in its history, followed by a discussion of the need for sustainable mining and how post-mining wind power may help fulfill it. Data processing methodology of field data from monitoring locations is then explained. The results are then used to estimate the electrical output of a wind turbine. This data is then utilized in a case study discussion of one of the monitored sites. The paper concludes with an analysis of the broader implications of the research and a discussion of future work."

Jan 1, 2011

By J. MCGUIRE, E. J. Haas, B. Demich

Near misses can enhance awareness of the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, the value of these reports and how they influence subsequent actions or controls to reduce on-the-job risks are unclear. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. The analysis provides insight into ways that risk-communication and management programs can be improved to reengage workers and their situational awareness on the job.

By M. A. Rabah

This paper focuses on the separation and extraction of lead and zinc from Egyptian ore at the Eastern Desert close to Red Sea. The ore sample contains cerussite, galena, hemimorphite and other impurities. Experimental program includes flotationof galena using xanthate collector and cerussite using oleic acid as collector and sodium silicate to depress hemimorphite tailing. Galena, and hemi-morphite are converted to carbonate with sodium carbonate prior to metal extraction. Lead and zinc are extracted pyrometallurgically at 1050°C and750°C or electrochemically respectively. The overall performance of the applied method amounts to 99.2%. Extraction efficiency of lead and zinc amounts to 98% and 94.5 % respectively. A model assumed that galena and cerussite in the ore are partially oxidized and can be liberated by grinding. Oleic acid selectively reacts with cerussite in a multistep sequence. Preliminary cost estimate shows that the price of the products is competitive to their local market prices.

Jan 1, 2000

Pillars with width to height ratios of less than 1.0 are frequently created in underground hard rock mines. The strength of slender pillars can be estimated using empirically developed equations. However, the equations can provide variable results when the width-to-height ratios approach 0.5. This paper investigates some of the issues affecting pillar strength at low width-to-height ratios in hard brittle rock. The investigation includes an evaluation of empirical pillar strength data presented in the literature and observations of pillar performance in underground limestone mines in the eastern United States, supplemented by numerical modeling in which failure processes and sensitivity of slender pillars to variations in rock mass properties are evaluated. The results showed that the strength of slender pillars is more variable than that of wider pillars. The numerical model results demonstrated the increasing role of brittle rock failure in slender pillar strength. The absence of confinement in slender pillars can result in a fully brittle failure process, while wider pillars fail in a combined brittle and shearing mode. The onset of spalling in slender pillars occurs at or near the ultimate strength, while this is not the case for wider pillars. Slender pillars are shown to be more sensitive to the presence of discontinuities than wider pillars, which can partly explain the increased variability of slender pillar strength. Two examples are presented, which illustrate failure initiation by brittle spalling and the sensitivity of slender pillars to the presence of discontinuities.

Jan 1, 2006

By A. Nieto

A dump edge and vehicle proximity warning system is being developed at the Colorado School of Mines using GPS and wireless local area networks to improve the safety of off-highway trucks in open pit mines. After two years of research, software development, and testing in the laboratory, field tests are currently being carried out at operating limestone quarries and open pit mining operations to evaluate the effectiveness of the system under rugged operating conditions. This paper describes the progress made on this NIOSH-funded project and discuss, tests carried out recently, at the Morenci open pit copper mine in Arizona.

Jan 1, 2002

By Randal J. Barnes

A system, such as a mine production system or a mine ventilation system which includes the movement of commodities or some material between decision points may, in many instances, be effectively modelled as a network. Mining has often been characterized as primarily a materials handling function. To a great extent this is true, even though it is an over simplification of all the activities involved in a mining operation. Accepting the materials handling characterization of a mining operation permits the extension of the characterization to a flow process. That is, the ore flows from the mining face through the mining phase (excavation & loading, hauling, dumping) through the milling phase (crushing, grinding, recovery) through the smelter phase and finally to marketing. With this concept it is possible to depict a mining operation as a simple network. For example consider an operation consisting of two mines (A and B) with mills at each mine (MA and MB) with the possibility open to treat ore from mine b at mill NB, but it is not feasible to treat mine B ore at MA. The product of both mills is sold.

Jan 1, 1983

By William L. Young

I think I should let you in on one of Canada's best-kept secrets, if you will promise not to tell it all over the place. Believe it or not, good, honest, enterprising capitalism is still alive and flourishing north of our common border, and I am living proof that capitalism is still working for the little guy. My personal story of mining development in Canada isn't all that rare -- you've probably heard something like it from other areas and other days several times -- but my case brings it up-to-date. I would like to Tell you briefly the history of Northumberland Mines Limited, a contemporary case of individual enterprise getting a mining operation underway. And if I can do it you probably can too.

Jan 1, 1981

By R. S. Kramer

A bulk compositional chemical analysis often provides incomplete information to help the mineral processor when faced with the problem of removing troublesome contaminants in low concentrations. Michigan Tech has developed a unique approach for addressing this problem. A combination of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and image analysis was successfully used to characterize the species responsible for phosphorus contamination of less than . 05 weight percent in iron ore. An automated routine acquired the chemical signature of each particle on a back scattered electron image. The few particles containing phosphorus were identified from the hundreds of particles examined, and the phosphate phases present were easily characterized.

Jan 1, 1993

The 2003 SME Annual Meeting and Exhibit will take place Feb. 24-26 in Cincinnati, OH. The meeting will feature a host of special symposia and programming geared toward the industrial minerals and aggregate industry sectors. This programming focus is particularly relevant for this annual meeting, as it will be hosted in the center of America’s transportation hub and industrial mineral center. Cincinnati, located on the Ohio River, is key to the movement of America’s supplies and construction material needs.

Jan 1, 2003

By L. Watters, R. Terry, D. Placha

Dense medium cyclones are the preferred means for cleaning 1/2 in. x 14Mesh to 28Mesh (12.7 mm x 1.0 mm to 0.6 mm) raw coal and are becoming a common choice for cleaning raw coal from a nominal top size of 2-1/2 in. to 3 in. (63.5 mm to 76.2mm) down to 14 Mesh to 28Mesh (1.0 mm to 0.6 mm). During the last ten years, dense medium cyclone circuitry design has undergone changes which have combined to improve process efficiency. This paper describes these improvements and compares present day design with the design used prior to the mid 1980's. Improvements in the following areas are described: Raw coal desliming, cyclone configuration, drain and rinse applications, dilute medium circuitry, and instrumentation and control.

Feb 24, 1997

By William A. Macaitis, Frank E. Dalton, Leo R. DiVita

The Metropolitan Water Reclamation District of Greater Chicago's Tunnel and Reservoir Plan (TARP) is a multi-purpose urban public works project with a total cost of $3.7 billion. Currently 51 miles of TARP tunnels are completed and operational and 34 miles are under construction. The excavated TARP tunnels have been constructed in rock utilizing 29 tunnel boring machines, ranging in size from 6.5 to 35.3 feet in diameter.

Jan 1, 1993

By D. R. Buist

The Taharoa plant of New Zealand Steel Mining Limited extracts a 57% Fe titano-magnetite concentrate from a large mineral sand deposit 90 miles south of Auckland on the west coast of New Zealand's North Island. The plant consists of an 18-inch suction cutter dredge which feeds a 750 TPH floating separation plant. An initial gravity/ size separation is obtained using cone concentrators. Finished concentrate is produced by a combination of conventional drum magnetic separators and top fed wet Mortsell magnetic separators. Concentrate is stockpiled by cyclone, and reclaimed by a bull- dozer and tunnel system. Repulped concentrate is pumped by sub- marine pipeline to slurry tankers anchored at a single buoy one mile offshore. Current concentrate production rate is in excess of one million metric tons per year.

Jan 1, 1973

By K. Huttu, A. van Wageningen

"The Kittilä underground mine in northern Finland is extracting one of the largest known gold deposits in Europe. Kittilä achieved commercial production on May 1, 2009, becoming Agnico Eagle’s first mine to open outside of Canada. The Kittilä orebodies were initially mined from two openpits – Suuri and Roura – and underground operations were added in October 2010. The pits were mined out in November 2012, so mining is now entirely underground in the Suuri and Roura deposits. Additional, small openpits will mine any remaining near-surface reserves in the future.The Kittilä Mine is located in the Lapland region of northern Finland, approximately 900 km (560 miles) north of Helsinki and 150 km (93 miles) north of the Arctic Circle. With a mine life estimated through 2034, Kittilä is Agnico’s longest-life mine.The mine’s proven and probable reserves contain 32 Mt (4.7 million oz) at 4.6 g/t (0.13 oz/ st) gold. Ore has been mined from underground since 2010. The original 3 kt/d (3,300 stpd) operation underwent an expansion project to increase the throughput capacity of the mill by 1 kt/d (1,100 stpd), starting by the end of 2014.The region around the Kittilä Mine is underlain by mafic volcanic and sedimentary rocks of the Kittilä Greenstone Belt oriented nearly vertical. This greenstone belt is similar to those hosting Agnico Eagle’s Canadian deposits in Quebec’s Abitibi region and Nunavut. At the contact point between ironrich and magnesium-rich rocks lies a 100- to 200- m (330- to 660-ft) thick structural zone known as the Suurikuusikko Trend. This trend hosts the Kittilä deposit, where multiple mineralized zones have been traced over a strike length of more than 25 km (15 miles).Most of Agnico Eagle’s work has focused on a 4.5-km (2-mile) segment of the Suurikuusikko Trend that hosts the five main zones of the known gold reserves and resources. From south to north they are: Ketola, Etela, Suuri, Roura and Rimpi.The ore at the Kittilä Mine is refractory, making gold extraction relatively difficult because the gold is generally locked inside the two main sulfide minerals – arsenopyrite and arsenic-rich pyrite. Only about 4 percent is very fine-grained “free gold” (not locked in sulfide grains) and easier to extract. Most of this free gold is found in the outer, oxidized or eroded sections of the ore."

Jan 1, 2015