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By Reno H. Sales

The syngenetic, metamorphic water, and source bed concept theories of ore deposition proposed by Anton Gray, C, Lo Knight and others, to explain ores in sedimentary rocks, are challenged on the basis of a survey of the literature and personal observation, A hydrothermal origin for the Northern Rhodesian Copperbelt deposits is indicated by the presence of post-Roan age igneous rocks and post-gabbro mineralization, the wide distribution of ore in the various Lower Roan lithologic types, and the zoning of the copper-iron sulphlde minerals and minor elements The proposal by Gray and Knight that igneous rocks are not favorable as guides to nonferrous metal deposits, and Gray's hypothesis that the redistribution of connate waters and their dissolved metals by metamorphic processes was responsible for the emplacement of ores, are rejected as contrary to field evidence, The absence of exposed potential igneous source rocks is shown to be an invalid argument for the proponents of any syngenetic hypothesis, The common association of ore deposits with calc-alkaline intrusive rocks and their derivatives is, however, demonstrated to be convincing evidence that an exploration program based upon a magmatic theory of origin, would have found most of the important known non-ferrous metal deposits of the world, It is urged that prospecting be continued on the sound basis of accumulated knowledge of the lithologic and structural facts surrounding known ore deposits.

Jan 1, 1960

By W. Z. Choi

A combined size reduction- liberation model of grinding has been developed to predict the product size distribution for both free and locked particles. The model is an extension of the population balance model for size reduction. Locked (or composite) particles have been subdivided into discrete classes of different compositions to obtain more detailed information. The model has been tested on a sphalerite ore from Tennessee. Liberation data have been obtained using an areal scanning technique on microscope images of polished particle mounts.

Jan 1, 1985

By J. Bickson, C. DeGennaro, J. Homer, M. Girman

Powered haulage and haul truck-related fatal accidents are among the most frequent at surface mines. Industry organizations developed guidance on accident scenarios to address haul truck and mobile equipment collision-related accidents. However, there is a need to investigate accident data to prioritize these scenarios and identify factors relevant to developing validation methods for collision warning/avoidance technologies and determining their capabilities and limitations. Standards and effective validation methods are necessary for improving system efficacy within mining operations and promoting industry adoption. To address these needs, researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated available powered-haulage and machinery-related fatal accident reports documented by the Mine Safety and Health Administration (MSHA). Their objective was to gain a perspective for informing the development of test protocols and validation methods through determining the most prevalent accident scenarios and related factors. Our findings afford insight for addressing the most prevalent haul truck scenarios and relevant factors within U.S. surface mining environments.

Mar 2, 2022

By D. Pearson

About 15,000 tonnes of zinc per year is present in the dusts and fumes produced in electric arc and BOS steelmaking, secondary copper refining and brass ingot making. Apart from the use of some copper-smelter fumes for zinc chemicals manufacture, zinc is not recovered and their disposal by landfill entails some risk of pollution by leach-out. The paper describes processes for recovering the zinc based on leaching and electrowinning. It was shown that the procedures normally employed for purifying zinc-electrolytes derived from primary sources are sometimes ineffective for secondary materials. Alternative process routes are proposed. Source materials were leached with acidic or alkaline reagents and solvent extraction was employed for electrolyte purification in addition to the usual techniques involving precipitation. Examples of integrated flow sheets for specific source materials are presented.

Jan 1, 1980

By Jenny Alsén, Hans Hogard

"Construction of large facilities underground in urban areas has many advantages. In order to show the advantages, a case study of the Norsborg metro depot in Stockholm Sweden has been made. The Norsborg metro depot will be the largest and most modern underground metro depot in northern Europe. The depot has been built in hard rock in an urban area with small impact on the environment and local residents. The paper describes how it is possible to build underground facilities in a cost efficient way and take care of the challenges regarding working environment that comes with locating a permanent working place underground. INTRODUCTION The Stockholm area is one of the five fastest growing regions in Europe and home to more than a fifth of Sweden's population on just two percent of Sweden's surface. The population is growing rapidly, with about 35,000 people per year and is expected to reach 2.6 million in 2030. In order to meet the development and enable continued growth, housing projects and expansion of infrastructure need to keep the same pace; this is an easy conclusion to make but much more difficult to realize in practice. The main challenge is to accomplish development in a sustainable and efficient manner, minimizing the use of resources and land. By constructing facilities underground more urban space will be made available for development and/or for greening of city centers. Considering sustainability factors such as land value in decision making for placing of structures or facilities, underground locations could become a first choice alternative. During 2015 and 2016, several major underground infrastructure projects in the city of Stockholm will start, including a 14 km sewage tunnel and an 18 km by-pass highway tunnel. Furthermore the Stockholm metro system is currently undergoing the largest expansion since the 1970’s, a 19 kilometers extension of the metro system including new trains and new stations is planned. During 2013 - 2015 Skanska Sweden took part in the construction of a new metro depot placed underground in the southern part of Stockholm; the Norsborg metro depot. This is a top modern urban underground facility that in 2017 will serve as depot for 17 new metro trains. The project was selected for “Outstanding Project of The Year” at the ITA Tunneling Awards 2015."

Jan 1, 2016

By Carl Rampacek

Laboratory and small-scale continuous pilot-plant investigations made at the Tucson Metallurgy Research Laboratory of the Bureau of Mines have demonstrated that the copper segregation process is applicable to the treatment of oxidized and mixed oxide-sulfide copper ores regardless of the gangue constituents. The process comprises heating the ore to a temperature of 750° C. with small quantities- of sodim chloride and coke to produce metallic copper, which then is recovered by flotation. Tests were made on' 23 copper ores of different types containing 0.8 to 5 percent Cu, .The copper recoveries ranged from 73 to 96 percent in concentrates assaying 10 to 62 percent Cu, depending on the grade and type of ore, The direct operating cost for a 1,000-ton-per-day furnace and flotation plant is estimated at about- $3 per ton of ore.

Jan 1, 1960

By Jim Britton

Sustained elevated metal and coal prices in 2011 continued to drive mining projects across British Columbia. The province is the top producer of copper, exporter of coal and the only producer of molybdenum in Canada. The province also produces significant amounts of gold, silver, lead and zinc and more than 30 industrial minerals. The total 2011 value of solid metal production is an estimated $8.6 billion and the outlook for 2012 is positive. British Columbia is poised to bring several new mines onstream in the next few years. Construction continues at the New Afton and Mt Milligan copper-gold projects that are anticipated to be open in 2012 and 2013, respectively. The provincial Environmental Assessment Office indicates there are 26 mine proposals in process with three currently under review and 23 in the preapplication stage. The following text briefly describes 2011 metal and coal mining activities in the five regions reported on by the provinces? regional geologists (Fig. 1).

Jan 1, 2012

By G. Folmo

Allis Mineral Systems' GRATE-CAR agglomeration/induration/reduction process is currently being operated to process ilmenite at Tinfos Titan & Iron KS in Tyssedal, Norway. In this process, balled ilmenite concentrate is fed to a traveling grate where pellets are dried and preheated, using fully oxidized kiln exhaust gas. Hot preheated, semi-indurated pellets are fed directly to a ported kiln where reduction of the ilmenite's iron oxide fraction occurs in the presence of lump coal. The reduced pellet sand coal char are discharged from the kiln to an indirect rotary drum cooler. Cooled pellets and char are screened and magnetically separated prior to their further processing in a downstream smelting operation. The pellets are melted and the titanium dioxide and iron are separated. Operation commenced in late 1986.

Jan 1, 1992

By J. A. Botín

Mining investment decisions are difficult since decision analysis is often based on scarce information. The sources of uncertainty in large mining investment projects are particularly numerous and are present in all evaluation stages. Hence the feasibility decision for projects of this nature will largely depend on how well these sources of uncertainty are managed to achieve bankable risk levels. The risk associated to the construction stages of a mining project is particularly difficult to quantify, mainly because the large number of variables affecting constructive yields, and the complex interactions among constructive resources. This investigation focuses on developing quantitative simulation models and tools to increase the value of a mining project by means of an optimization of the preproduction equipment fleet. The models were validated through their application in the Chuquicamata Underground Mining Project.

Feb 23, 2014

By George Joseph Malina

Contractor chose and Owner allowed concrete to be placed using the arch first principle while excavating the 35'-3" O.D. rock tunnel. The contract included excavating and lining 26,000 L.F. of rock tunnel to 33'-I.D. Concrete was placed at a rate of 90LF per working day using a movable bridge to allow batching, mixing and pumping of concrete adjacent to the tunnel form.

Jan 1, 1981

By J. Kretschmann, H. Mischo, O. Drusche, S. Krause

Mining is and will be inevitable in spite of the increasing implementation of circular strategies. The energy transition and population growth will boost the demand for critical raw materials. It is the opportunity for miners to reinvent their business models. Generating attractive new business cases with sustainability-oriented innovations meets investor and stakeholder expectations from the beginning. This contribution guides managers on their pathway towards sustainable success. Contextual sustainable business model patterns will be presented that can be adjusted individually, regardless of actor’s size. It will also point out, how sustainable value creation can be measured on business model level.

Feb 1, 2023

By K. Dagdelen

The definition and shortcomings of traditional cutoff grades are discussed. The concept of optimum cutoff grade policy which maximizes the Net Present Value (NPV) of annual cash flows coming from a mining project is introduced within the basic framework outlined by K. F. Lane. Several examples are used to demonstrate the shortfalls of cutoff grade policies obtained by various heuristic optimization techniques. An algorithm to obtain an optimum cutoff grade policy which maximizes the NPV of a project is given and described in detail.

Jan 1, 1993

By W. J. Schitt

Section 15 covers a loose collection of topics that involve water in some way. The chapters in this section include Dredge and Placer Mining (Chapter 15.1), Solution Mining: Surface Techniques (Chapter 15.2), and Solution Mining: In Situ Techniques (Chapter 15.3). The dredge and placer systems involve water in several forms. The segment on hydraulicking or hydrosluicing discusses the use of monitors to direct high-pressure water jets to move material. As such, this represents an alternative to mechanical breakage, loading, and hauling. This chapter also covers placer mining (except dry placering) where the water provides the medium that promotes the separation of minerals based on their density and other settling characteristics. Thus placer mining is generally limited to concentration of gold, tin ore, diamonds, and other heavy minerals that are already liberated and are contained in a less dense matrix. The third topic, straight forward dredging, as in sand and gravel operations, involves water only in an incidental way. Here water simply covers the minerals of interest. Thus the dredging system need only lift a payload from the submerged location to the surface for further processing or handling

Jan 1, 2008

By Richard Cole

The Energy Act of 1992 has many users of ac-induction motors eyeing premium-efficiency motors with mixed feelings and perhaps some confusion. When the October 1997deadline arrives for compliance with the1992 standards, the winners will be the environment due to reduced need for more power generating plants and the petroleum economy because of reduced dependency on foreign oil. But what will it mean for industrial users? The most obvious benefit is the potential for smaller electricity bills. Motors account for about 64% of the electricity consumed in the United States, at a yearly cost of $112 billion. Every 1% reduction in motor demand cuts 0.64%, or $716 million, off the industry wide bill. Higher efficiency motors also run cooler. This lightens the load on air-conditioning systems and further reduces plant demand. Lower total demand can lead to lower rates by helping to minimize peak-demand surcharges. As rates increase over time, these savings get bigger.

Jan 1, 1996

By R. L. Summers

The tremendous engineering advances occurring during this past century are very evident within the boundaries of the Anthracite Section of AIME. The Steelton plant of Bethlehem Steel Corporation, located along the Susquehanna River just east of the Commonwealth's capital at Harrisburg, for more than 105 years has experienced a most dynamic life which has paralleled America's industrial growth. (Figure 1) In June 1865, just after the Civil War, a group of men met to organize the Pennsylvania Steel Company. The war had brought into sharp focus the vital importance of the railroads to the country's expansion. Until that time wrought iron rails were used, and the replacing of track after only several months wear had become an almost unbearable cost. The spirit of free, competitive enterprise and the prospects of a lucrative market compelled these men to form that first Pennsylvania Steel Company and to develop better rail products. They issued the following statement: "...our desire to free ourselves from dependence upon a foreign market (has) led to the organization of the Pennsylvania Steel Company, and the parties who have connected themselves with it are determined to produce upon American soil all the principal manufactures of steel that are now, at such a serious cost for freight, commission, insurance, exchange, duty, etc., and often, with so much delay and uncertainty, imported from abroad. (We) are preparing to establish near the consumer, works at which articles of accustomed pattern will be promptly produced, and from the

Jan 1, 1971

By Kim Lapakko

Increasing public concern over the welfare of the environment has placed demands on the mining industry to evaluate the environmental impact of mining development. This is a difficult task and involves considering the influence of a multitude of variables on complex processes over a long time period. Few studies which focus on the evaluation of the environmental impact of mining have been conducted and, therefore, there is little past experience to rely upon. This article describes some of the work done to evaluate the potential environmental impact of mining development in Minnesota. Interest in developing the major copper and nickel sulfide deposits near the wilderness areas of northeastern Minnesota aroused concern regarding the environmental impact of mining development in the region. As a result laboratory and field studies were initiated to investigate the potential for trace metal leaching and acid generation due to dissolution of Duluth gabbro. Chemical equilibrium computer modeling was conducted to aid in data interpretation. The goals of the study included the investigation of leaching mechanisms and rates of release (1, 2).

Jan 1, 1980

By M. J. Hrebar

In the summer of 1990, a study was conducted to document large tractor (i.e., Caterpillar Dl1N) utilization in surface coal mining. The tractors were found to be utilized as primary production machines and in combination systems with blast casting and draglines and blast casting and excavator/truck systems. In addition, dozers were used to prebench ahead of a primary dragline system. The study also established ranges and averages for Dl1N operating costs and mechanical availability. Based on simulated production of various tractor dozing applications, the potential for low cost coal stripping was suggested (Hrebar, 1991). A follow-up study, also funded by Caterpillar Inc., was conducted in the summer of 1991 to determine actual production rates in two dozer stripping applications. These actual production rates would then serve as a foundation for estimates of stripping costs. This paper presents the results of the studies in a contour and a cast application.

Jan 1, 1992

By R. R. Kallu

The current 120 psi seal design and evaluation practices are mostly based on simple analytical solutions. Considering the simplistic assumptions and limitations involved in simple analytical solutions and practical difficulties involved in conducting conventional full-scale explosion tests for evaluating 120 psi seal designs, there is a need for developing new scientific methods and engineering practices for design, analysis and evaluation of mine seals.

Jan 1, 2010

By Nick Karl, David Wilburn

"The mission of the U.S. Geological Survey (USGS) National Minerals Information Center (NMIC) is to collect, analyze and disseminate information on the domestic and international supply of and demand for minerals and mineral materials essential to the U.S. economy and national security. Understanding mineral exploration activities and trends assists government policy makers, minerals industry decision makers and research entities in identifying where future sources of mineral supply are likely to be discovered, the amount and type of these resources and factors that may affect exploration and development.This review summarizes significant exploration trends related to active sites and budgets, mineral commodities and regional factors for the years 2001-2015. Data were compiled by specialists in the USGS-NMIC, and reported annually in the USGS-NMIC Minerals Yearbook series and in the May issue of Mining Engineering magazine. External data for these analyses were derived from industry sources, published literature, and SNL Metals & Mining, an offering of S&P Global Market Intelligence (New York, NY).The USGS-NMIC compiled exploration site data for more than 80 mineral commodities, focusing on base metals, diamond and precious metals. More than $138 billion constant U.S. dollars were budgeted by the minerals industry from 2001 through 2015 to explore more than 16,000 mineral deposits globally (SNL Metals & Mining, 2016a). Annual analyses identified where mineral exploration took place by principal commodity target, ranked the magnitude of activity in each region, identified the factors that most affected changes in exploration activity and highlighted developments that led to changes in global supply or increased diversity of supply to the United States. Geographic classifications noted in this report were Africa, Australia, Canada, China, Latin America, Pacific, Russia, United States and Rest of the World."

Apr 1, 2017

By W. F. McDermott

The transportation of solids by pipeline is not new. In 1891 a United States patent broadly covering a method of pumping coal with water was granted to W. C. Andrews. His pilot plant was constructed on what is now the site of the New York Public Library in Manhattan. His process was applied to pumping coal mine waste back into the worked out portion of coal mines. On October 26, 1967, the world's first long distance iron ore slurry line was put into service by Savage River Mines. The commissioning of this 5.0 million dollar installation climaxed three years of development, testing, and construction and proved the Company's faith in pioneering this unique transportation method for iron ore. This paper will discuss some of the more pertinent items in connection with that three- year period. Also to be discussed will be the operation of this line during the past eleven months.

Jan 1, 1968