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By J. L. Hendrix, M. Ahmadiantehrani, G. Ramadorai

The concept of hypochlorite treatment prior to cyanidation in the heap leaching of low grade carbonaceous gold ores is discussed. Laboratory column leach tests using a low grade carbonaceous ore were performed to investigate the effects of pH, hypochlorite consumption and concentration, and bed height on total gold extraction. At high pH, hypochlorite stability increases and thus, hypochlorite consumption decreases. At room temperature, total gold extraction is proportional to hypochlorite consumption. However, at some point additional hypochlorite consumption does not increase gold extraction. Gold recoveries of 10% and 80% are achieved at 12 and 167 lb/ton hypochlorite consumption, respectively. Increasing hypochlorite concentration increases the rate of extraction. For a given hypochlorite consumption, gold extraction increased with decreasing ore bed height. Finally, using calcium hypochlorite results in higher gold extraction than using sodium hypochlorite at a fixed hypochlorite consumption.

Jan 1, 1992

By John A. Shuster, Joseph A. Sopko

Construction of two shafts, as well as associated deep concrete structures, for a major storm sewer project in Milwaukee, Wisconsin required ground water control and temporary ground support to depths ranging from 19.2m to 55.0m. Lowering of the site ground water table eras not possible because of potential consequences for existing nearby structures. Construction entailed completion of two shaft collars into bedrock. In addition to the shafts, several adjacent connected. structures were completed. Ground freezing was selected to provide temporary ground support and ground water control for all excavations. The first application of using reinforced frozen earth was successfully incorporated on the project. The procedure enabled the contractor to create openings in excess of 9.1m in height, without bracing, through highly stressed frozen earth walls. Design features and construction procedures for completion of ground freezing and related excavation are reported.

Jan 1, 1989

By Paul D. Tomlingson

Editor's note: This is the second of two articles on maintenance. Part one: "Downsizing maintenance to improve performance: Defining the downsizing task," appeared in the September issue of MINING ENGINEERING, pp. 1065-1066. Part one explained that downsizing must he an organizational change in which the mine moves to a more efficient, smaller maintenance organization. But the new, smaller organization must operate more productively. Determine initial reduction targets Reduce the workload - The initial reduction target can be determined by projecting manpower reduction as a result of discontinuing or deferring work. Start these reductions by not replacing personnel who retire or are disabled. Observe the right craft mix during this initial reduction. Improve productivity - Further reductions can come from better productivity. But achieving the higher productivity level will require a year or more. During this transition, the efficiencies of a well-defined program and a team organization must take hold.

Jan 1, 1994

By J. A. Cole

Santa Fe Pacific Gold's Lone Tree mine is located in Humboldt County, NV, 45 km (28 miles) east of Winnemucca. The mine currently operates a 1.74-Mt/a (1.92-million stpy) run-of-mine heap-leach operation and a 2.27-kt/d (2500 stpd) refractory gold¬ore-processing plant. Most of the mill-grade ore reserves are refractory, mainly due to pyrite and arsenopyrite encapsulation of the gold. The autoclave pressure-oxidation circuit was commissioned in February 1994 to process the refractory ore. Mineralogy unique to the Lone Tree deposit allowed for the design of a partial-oxidation process. It takes advantage of the heterogeneous nature of the pyrite morphology. Partial oxidation has resulted in an autoclave plant that is able to achieve low operating-unit costs (Figs. 1 and 2).

Jan 1, 1995

By M. Kyzeridi

The paper presents a study on the reclamation of two mined-out bauxite open pits in the area of Kefali, Itea, Greece. The mining area has been reclaimed partially in the past, but its proximity to the town of Itea and a national road with tourist traffic, rose the interest to examine various scenarios for improving the landscape and the aesthetics of the site and introducing alternative land-use for recreational activities. Geospatial data were modelled using a Geographical Information System (GIS) that made it possible to study alternative proposals in terms of final landscape profiles, volumes required to be moved and the associated costs.

Jan 1, 2002

By John Durkin, Steven Wirch, Fred N. Kissell, Steven Ruggieri

The Bureau of Mines has developed two expert systems to give advice on coal mine dust control, one for continuous miner sections, and another for longwalls. Prototype versions have been evaluated by coal operators and MSHA. Both systems query the user as to the nature and extent of the dust control problem. Typical questions asked deal with matters such as cutting sequence, current dust standards and characteristics of current dust control techniques. Advice given by the system generally does not focus on a single issue, but may suggest a variety of approaches consistent with the ability of the operator to practically implement what is suggested. Both were written using expert system development software called Insight 2+. The advantages of Insight 2+ for the user are: low cost, IBM-PC compatibility, and the fact that little prior experience with computers is required. For the developer, Insight offers an easy to use production rule language and goal driven structure as well as a wide variety of capabilities.

Jan 1, 1987

By K. H. Al-Rawahy

Mineral resources comprise of metallic, non-metallic, and fossil fuels. Our civilization, and the associated economic and industrial developments are inherently dependent on the availability and use of minerals. This is evident from historical development and identification of civilization eras throughout human history: the stone age, the iron age, the bronze age, and the current computer age. This paper deals with the depletable fossil fuel sector of minerals; this is represented by crude oil, natural gas, and coal. Fossil fuels provide approximately 80% of total global primary energy supply; the rest being provided by renewables (wind, hydrothermal, solar), nuclear, and biomass. Economic, industrial, and population growth will, inevitably, lead to an increase in demand for energy. In general, per capita energy consumption is correlated with per capita income, with the US showing the highest energy use per capita, and South Asia having the lowest. This paper examines the underlying interrelated issues (factors) of energy reserves, production, scarcity, depletion, economic, and technological factors and impact on long term availability and thus sustainability. Is it possible to extend the time to economic depletion of these resources? This will have an impact, direct or otherwise on total energy availability, and the inter-temporal allocation of the resource. Specific economic and physical parameters relevant to mineral supply and their respective impact on depletion, and inter-temporal welfare are investigated. These variables include own price, substitute price, population, income, technical innovation-both on supply as well demand, and resource substitution.

Jan 1, 2007

By John C. Cook

In reasonably dry rock, long-wave radar can theoretically explore to distances approaching 75 meters (250 ft). High-resolution radar reflections have already been demonstrated through 13 m of hard limestone, through 9 to 18 m of coal in place and through 225 m of rock salt, using only low-power experimental radar equipment. Radar reflections have been received through the rock from rough pillar walls, from faults, and from a slim, uncased, vertical drill hole. In three years of intermittent experimentation, the feasibility of rapid radar exploration of large volumes of rock, with portable equipment, in deep, wet workings has been demonstrated. With future, improved equipment the theoretical working range, of the order of 75m, is expected to be attained in most hard rocks. THE TECHNIQUE Fig. 1 illustrates an early "monocycle" radar system (1) set up in a coal mine. This radar equipment is entirely different from that employed for detecting distant objects through the atmosphere. However, the basic principle is the same: a pulse of electromagnetic energy is radiated by the transmitter, a portion is reflected by some "target" object embedded in the surrounding medium and some of this energy is collected by the receiving antenna. In the receiver, the pulse is amplified, is "stretched out in time" by a sampling process, and is displayed on the screen of a cathode-ray oscilloscope. It may also be recorded on paper or magnetic tape. Fig. 2 illustrates a

Jan 1, 1997

By G. Barrasso, E. Nordheim

"The European aluminium industry, through its member organisation the European Aluminium Association (EAA), initiated a program on sustainable development for the aluminium industry in 2001. The first step involved the development of a set of sustainable development (SD) indicators for the industry, taking into account of the different interests involved and also the different existing conventions. The indicator set was developed during 2001 and 2002 with the assistance of recognised partners, including Wuppertal Institute from Germany and Versailles University from France. As well, both internal and external stakeholder groups were involved in order to validate the indicators. This has resulted in a set of thirty-four indicators used in the first survey exercise. In the survey the EAA, together with the national aluminium associations, attempted to cover all European plants producing alumina, primary aluminium, rolling ingots, extrusion ingots, foil and recycled aluminium -covering approximately 800 plants. The survey used two points in time, 1997 and 2002, in order to start developing a trend for the individual indicators and to measure progress over time. The industry response to the survey was very positive, with a total industry coverage based on tonnage reported of over 80% for 2002 data and 70% for 1997 data. The results also show a solid progress for most indicators and particularly for social indicators such as training performance, community involvement and employees health programmes. The EAA is committed to conducting this as a regular exercise and is engaged in a number of stakeholder workshops in order to present the survey results, to review the indicators used and to also consider adjustments of these based on feedback from stakeholders and experiences from the first data collection."

Jan 1, 2005

The Newmont Boddington Orebody (NBO) is a large, diffuse Au/Cu orebody in Western Australias South-West corner with approximately 20Moz Au in current Reserves. The current sulphide Resource is reported after calculation with the non-linear estimation technique Uniform Conditioning to account for the mining selectivity being smaller than the average drillhole spacing. Simulation of Au grade is also run over the entire orebody reviewing risk and uncertainty. There are differences in results from the two methods. These have been investigated and the lessons learned of the influencing parameters and effect of technique alone, are helpful for applications to other orebodies.

Jan 1, 2010

By Richard P. Killmeyer, Carl P. Maronde, W. W. Wen, Peter J. Suardini

Under a cost-shared Department of Energy contract, awarded as part of the Coal Preparation Program&apos;s High Efficiency Preparation subprogram, Custom Coals International will be installing and testing a 227 kglhr micronized-magnetite cycloning circuit in PETC&apos;s Coal Preparation Process Research Facility. The project includes the design, construction, testing, and decommissioning of a fully integrated circuit complete with feed coal classification to remove the minus-30-micron material, dense-medium cycloning of the 300 by 30 micron feed coal using micronized magnetite (<10 microns), and medium recovery via drain & rinse screening and various stages and types of magnetic separation. This paper will describe the micronized-magnetite beneficiation technology and the scope of work for this project including an update on the status of the project, the circuit, and the proposed test plan.

Jan 1, 1995

By J. Kretschmann

Southeast Asian countries cannot maintain their economic growth rate without the development of their mining industries. To make this development as sustainable as possible requires sound fundamentals securing not only economic progress and environment protection but also improvements in occupational safety and health (OSH) for the miners. Mining in South East Asia is still very labor intense and dangerous. Tremendous achievements from world class mining operations in advanced mining countries can be used as role models to improve the status quo of the Southeast Asian countries in OSH management. Know-how transfer, therefore, is a key factor for major improvements. Effects of this transfer based on a multi-level approach will be discussed based on a case study. It describes the transfer from German to Vietnamese hard coal mining industry. Crucial requisites for excellent achievements in OSH in Southeast Asian mining countries are also mentioned.

Feb 23, 2014

"Foreword by Lisa SchlinkSuperintendent, operations, Freeport-McMoRan Inc.,Green Valley, AZ, USAThe sixth annual Student Poster Contest hosted by the Mineral & Metallurgical Processing Division of the Society for Mining, Metallurgy & Exploration was held during the 2015 SME Annual Conference and Expo in Denver, CO. The contest had another record-breaking attendance of 31 entries: 27 graduate and four undergraduate. The universities represented were: Colorado School of Mines, South Dakota School of Mines and Technology, University of Kentucky, University of Utah, Southern Illinois University Carbondale, University of Wyoming and West Virginia University.The competition began with an extended abstract review by a panel of judges selected from MPD members. At the SME Annual Conference, all students displayed their posters, highlighting their research. The students with the top abstracts from the graduate and undergraduate divisions presented their research at the MPD Student Poster Session Wednesday morning. The panel of judges then provided tallied scores for the abstract, poster and presentation to determine the winners of the 2015 Student Poster Contest. The first- and second-place winners of both the graduate and undergraduate divisions received $1,000 and $500 scholarships, respectively. The third through seventh places received $200 each, and all other entrants received $100 each and were invited to join the MPD Luncheon.In the undergraduate division, Annette Hein of the University of Wyoming received first place for her research on “Solvent Extraction of Europium from a Nitric Acid Solution.” Second place went to Jennifer Galvin of South Dakota School of Mines and Technology for her research titled “Solvent Extraction of Neodymium Using PC88A.”In the graduate division, Caelen Anderson of the Colorado School of Mines received first place for his research titled “Fundamentals of Rare-earth Flotation Surface Chemistry: Hydroxamate Adsorption on Bastnasite”. This is Caelen’s fourth year placing in the top finisher. Second place in the graduate division went to Seyed Hassan Amini of West Virginia University for his research on “Ultra Clean Coal Production for the Solar-cell Industry.”The 2015 Student Poster Contest was chaired by Lisa Schlink (Freeport- McMoRan Inc.) and Emily Sarver (Virginia Polytechnic Institute and State University). The panel of judges included Aaron Noble (West Virginia University), Nick Gow (FLSmidth), Ren Bryce (Freeport-McMoRan Inc.), David Perkins (Derrick Corp.), Jim Metsa (Weir Minerals) and Scott Shuey (Newmont).A special thank you is extended to the sponsors of the MPD Student Poster Contest, to all the students who participated and to the panel of judges. Watch for more information on the 2016 MPD Student Poster Contest to be published later this year on http://www.smenet.org/mpd/ and in the November issue of Minerals & Metallurgical Processing."

Jan 1, 2015

By Allan E. Koski

Michigan is the second largest iron ore producing state in the United States. The Empire Mine, celebrating its 30th anniversary in 1994, is the largest iron ore mine in the state. The Empire Iron Mining Partnership is an iron ore mining, concentrating and pelletizing facility managed by The Cleveland-Cliffs Iron Co., a subsidiary of Cleveland-Cliffs Inc. The Empire Mine is located near Palmer, MI on the Marquette Iron Range in Michigan&apos;s Upper Peninsula. The partnership includes Inland Steel Co., LTV Steel Co., Wheeling-Pittsburgh Steel Corp. and Cleveland-Cliffs. Mine construction began in 1960. The first pellets were produced in late 1963. Successive expansions in 1967, 1974 and 1979 resulted in Empire reaching a present annual capacity of 8.1 Mt (8 million long tons) of pellets. In late 1993, a milestone was reached with the production of Empire&apos;s 152-Mt (150-millionth long ton) of iron ore pellets.

Jan 1, 1994

By R. E. Cook

"Mineral deposits require substantial amounts of energy to transport and be processed into useable form, and as such present a real processing challenge in that the deposits are never homogeneous and ore body compositional characteristics are all over the map! Extracting the desired mineral(s) from the deposit at sufficient profit margin, despite severe fluctuations in market price, requires process automation architecture capable of supporting an integrated enterprise solution. Such an architecture will encompasses the activities of individuals, process units, process areas, plant level activities, mine management and business planning and accounting systems. Key to the automation process is the aspect of value generation. This paper brings together the various requirements for the automation of a mining enterprise and presents the different aspects of how to obtain value across the entire mining operation.INTRODUCTIONMinerals’ processing sites are historically long lived, 20 year life of mine is not uncommon and 75 years is not unheard of. Considering that hardware technology advancements are introduced every six months, or less, it is prudent to select process automation systems that adhere to “open” industrial standards versus proprietary based systems. In the minerals processing industry, the key to survival is driving the cost of production per unit volume to the lowest possible level and provide enough profit to sustain operations. Control system architecture and Business information technology are rapidly becoming important tools in the quest for productivity. Getting key dynamic business performance information at the right time to the right person or process unit is crucial to successfully achieving corporate goals. The process automation architecture selected must therefore be able to integrate to the various networking enterprises and business systems.The mining industry is generally known as an “extractive” industry that is very physically-oriented with respect to operations and the activities in which workers engage. Large numbers of people performing manual tasks in difficult surroundings, produce very variable outputs. But, times are changing – and so are industry best practices. While the nature of work still consists of activities such as ore extraction, ore movement, ore concentration, refinement and logistics, automation innovations are starting to change the nature of many of the production steps. The industry has transitioned from requiring more physical activities by workers, to more information management, automated control and collaboration within the operation. Humans are good at situational intervention and non-linear reasoning and do best when empowered with an overall production perspective. Machines and automation are good at repetitive functions, steady state operation, and managing transitions. Thus, a combination of advanced technology solutions, reliable and useful information and full human contribution are necessary to mining operations for value generation."

Jan 1, 2015

By Elena Chiriotti, Federico Valdemarin, Jan Cenek

"SUMMARY The “28 May Station” is the only transfer station between the existing Green and Red metro lines in Baku. As part of the huge development strategy of the metro network, the complete separation of the existing underground lines has been planned at this location, in order to simplify the operation of the future metro system. The extreme challenge of the project is represented by the need of achieve the separation of such lines over a breakdown of the operation of just five weeks. The lack of direct access from the surface, a complex geology with artesian water layers, a congested underground space and sensible buildings represent additional constraints. The chosen design solution consists in creating a complex steel pipe jacking frame around the operating tunnels and then excavating under such frame two large caverns where the separation of the existing lines and the construction of the new metro tunnels will be achieved. Soil treatments have been conceived to mitigate the geotechnical risks and to reduce possible impacts on the existing structures. The paper illustrate the challenges of this extraordinary project, one of the most complex underground structures under study, the design solutions and the risk management approach used to manage the complexity and to design the mitigations measures. INTRODUCTION The metro network in the capital of Azerbaijan is rapidly growing together with its metropolitan area. The beginnings of the existing metro system started in Baku in 1967 in Soviet times. To date, only two lines (Green and Red) are in operation with a total length of 34 km, including 23 stations. The future network will be much wider: besides the construction of three completely new lines and the extension of two existing lines, the whole metro project includes the development and modernization of the existing metro sections. A consortium formed by Systra (leader), Mott MacDonald (Praha) and Saman (Korea) awarded the contract for the preliminary and detailed design of infrastructures for the extension of Baku Metro Network. This extension consists in 83 km of new lines and extension of existing lines. As part of this modernization project, the connection of the Green Line at the 28 May / Cefer Cabbarli Stations, focus of this paper, represent also it’s ""Achilles' heel"" given that the already very congested system have only one transfer station."

Jan 1, 2016

By P. Conrad, S. Rosenthal

"Engineers remain in demand. Job opportunities in the United States still exceed the number of students graduating from college with degrees in Mining Engineering. Although enrollment is up for freshman studying Mining Engineering, many of those students will either change majors or not complete their degree, maintaining that deficit of available Mining Engineers. What can be done to ensure that enough Mining Engineers will graduate to fill the needs of the mining industry over the next ten to 20 years? The authors believe that this need can be met by recruiting students to Mining Engineering programs who are genuinely interested in working in the mining industry. With this in mind, Montana Tech conducted its first Mining Engineering camp in July 2014 to get junior and senior high school students interested in careers in the mining industry by showing them that Mining Engineering is both an exciting and rewarding career. This paper discusses What a Blast! The 2014 Montana Tech Mining Camp. INTRODUCTION The concept of summer camps for high school students is not new. For example, Missouri University of Science and Technology has offered their “Explosives Camp” for several years. A large percentage of attendees to these camps discover or confirm an interest in Mining Engineering and enroll in the school’s program. The Dean of the Montana Tech School of Mines and Engineering challenged department heads to develop and offer summer camps for prospective high school students to get a taste of engineering with the goal being to improve recruitment for each discipline. Mining Engineering embarked on the concept of a summer camp in 2013 with a concept to provide a week’s experience in Mining Engineering during the summer of 2014. What it takes to progress from concept to reality, with some of the learnings to be shared, follows."

Jan 1, 2015

By Peter Zhang, Daniel Su

Following the first longwall excavation at a deep-cover gas well site, the pre-mining modeling prediction of longwallinduced casing deformations in the fully cemented production casing were in excellent agreement with post-mining Caliper survey results. However, after second panel mining, the post-mining Caliper survey revealed a large plastic deformation near the top of the Pittsburgh Seam. The focus of this paper is to identify the possible cause of such an anomalous deformation. Very high longwall-induced casing stress near a thick claystone layer at 23 feet above the Pittsburgh seam horizon was identified as the primary cause. Leaving the production casing uncemented or using softer cementing material between intermediate and production casings is identified as the best practice.

Feb 1, 2024

By John P. Fillion

This paper will present an overview of conveyor haulage systems. Technical and economic feasibility will be examined as conveyor haulage is applied to large western surface coal mines. Theoretical analysis and actual cases will be presented from NERCO Coal Corp. experiences in bringing this application to their Western mines.

Jan 1, 1989

By Rafael C. Castro, Paul V. Savard, Kathleen M. Murtagh

Preliminary design is underway for the Massachusetts Water Resources Authority’s (MWRA) next major tunnel program, the Metropolitan Water Tunnel Program (MWTP). The MWTP is the latest part of MWRA’s ongoing efforts to achieve redundancy for its metropolitan water transmission system including its historic deep rock City Tunnel, City Tunnel Extension and Dorchester Tunnels. The MWTP comprises several deep rock tunnels that will be approximately 10-foot to 12-foot finished diameter totaling just over fourteen miles long and ten connections to existing large diameter surface piping and pumping stations. This paper will present an update on current engineering and permitting efforts, packaging schemes, and the schedule to complete the MWTP.

Jun 13, 2023