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By Daniel Brutto

"Environmental considerations are a key driver within marine mining consenting processes across different national and international legislative regimes and are critical in shaping the global public perception of the industry. As a result, it is vital that mining companies seeking to operate within marine environments establish a robust understanding of the sensitivities of the seabed environments in which they are active, the impacts of their activities and the ability of the environment to recover from these impacts. The significant risks of failing to do so include an inability to either obtain or maintain operating permits. At the individual project level, the environmental effects of any given development project are typically defined within the scope of an Environmental Impact Assessment (EIA). For well-established industries operating in well-studied environments this approach typically works well. However, where emerging industries or existing industries that are operating within new environments are concerned, there may be significant knowledge gaps pertaining to our understanding of how specific anthropogenic practices or activities interact with the marine environment. These knowledge gaps can cause significant uncertainties pertaining to the likely significant effects of a project. Such uncertainties may result in barriers to industry and economic progress, increased consenting risks, increased project costs to be borne by individual project developers through the acquisition of additional environmental data during the pre-consent or post-consent project phases, project delays and/or significant increases in environmental monitoring burdens with corresponding increases in project costs."

Sep 1, 2014

By Z. H. Zhou

It is difficult to remove cadmium from raw indium using only electrolytic refining because their standard potentials are similar. In this paper, physical and chemical methods were used to remove Cd from raw indium. Indium metal is vacuum refined for two hours at 400°C with a vacuum pressure of 20 Pa. In this process, 99.70% of the Cd can be removed. The removal rate of Cd reaches 90% to 95% when indium is further smelted for 10 minutes in a 20% glycerin solution of KI and I2 at 180°C. When pre-indium is electrolytic refined in an In2(SO4)3-H2SO4 system, in which the indium content is 80 to 100 g/L, the pH is 2.0-3.0 and the current density is 80 to 100 A/m2, the contents of the impurities decrease and the purity of the indium product reaches 99.99%.

Jan 1, 2007

By Michael E. Stickney

"Soft technology" computers and computer programs-brings to mind a room full of machines, tape drives, disks, plotters, and printers spitting out financial reports. Computers now have a much broader scope of applications because of reductions in equipment size and cost. For example, people now interact directly with computers to control events. Such computers and associated equipment-called interactive control systems-are often small, relatively inexpensive, and can be designed to increase productivity at mining operations. This is accomplished by improving communications between individuals; giving employees the information needed to make decisions in real time, as events are happening; and giving individuals the background needed to perform more effectively. This paper will describe a procedure for determining the return on investment for interactive control systems, and describe four such systems. The analysis process is general in nature and can be applied to any type of mining operation or production process.

Jan 4, 1981

By Charles L. Allie

Since Reserve Mining Co. began commercial operations at Silver Bay, MN, some 25 years ago, major improvements in taconite processing technology have become available. In addition, significant new government standards have been imposed on industrial operations. By implementing a $370-million modernization program, Reserve was able to accomplish two major company objectives: the quality of concentrates produced from the Peter Mitchell mine has improved, and the operation meets both present and foreseeable environmental standards. Process modifications at Reserve were designed to: •Reduce the pellet silica content from 9% to 5%; •Increase the pellet iron content from 62.5% to 65.8%; •Implement a tailings disposal system utilizing "best available technology" water quality controls; and •Reduce air emissions by installing "best available technology" air emission controls. By adding dry cobbing, fine screening, and flotation to the concentrating process, pellet silica content has been reduced; the process reclaims and reuses all process waters; all tailings are stored in a zero discharge tailings basin; and all air emission standards are being met. Initial Beneficiation at Silver Bay Reserve's Peter Mitchell mine at Babbitt, MN, is on the eastern end of the Biwabik iron formation. The open-pit mine is approximately 16 km long, 0.8 km wide, and presently has a maximum depth of about 50 m. Principal constituents of the ore body are magnetite, quartz, and iron-magnesium silicates. The company's large commercial plant began operating at Silver Bay, 75 rail km from the mine, in 1955. Facilities have historically had the capacity to process 31.5 Mt/a of taconite, containing an average 24% magnetic iron, into 11 Mt/a of iron ore pellets. Reserve's initial beneficiation process-which existed up to early 1979-consisted of two crushing stages at the Babbitt mine site, two additional crushing and screening stages at Silver Bay, grinding in a conventional rod-ball¬regrind mill circuit, size classification with cyclones, and concentration with magnetic and hydraulic separators. Concentrate produced by that circuit assayed 65% iron and 8.5% silica, with a screen analysis of 94% -44 µm, and a surface area of 9300 cm2/cm3. Pellets produced from this concentrate assayed 62.5% iron and 9% silica (dry basis). Construction began in 1977 to modify Reserve's operation. Process modifications were designed from pilot scale operations that had been operated and researched by Reserve for more than 10 years. There were two design restraints imposed on the process: economic constraints that Reserve continue to use much of the existing processes and structures in the new operation; and a substantial number of government-imposed permit constraints. In effect, the tailings process was designed first and then a concentrating process was developed that would "fit" the tailings disposal system. Operation of the modified process began in June 1980. Crushing Remains Unchanged No changes in process flow were made at either the Babbitt mine and crushing plant or at the Silver Bay fine crusher. Gyratory crushers reduce run-of-mine taconite to -90 mm-diam at the mine. Taconite is then transported to Silver Bay by intra-plant railroad. There are 10 fine crushing lines. Each consists of a double deck screen, followed by a heavy duty short head crusher, a second double deck screen, and second short head crusher. All screen undersize material bypasses the crushing lines, resulting in an open circuit crushing process. Fine crusher product is approximately 98% - 20 mm, 80% -12 mm, and 50% -10 mm in diameter. Each fine crusher line processes about 400 t/h of crude taconite. Cobbing Provides Aggregate for Tailings Dams The first major process change was the addition of dry cobbing, a dry magnetic separation step between the fine crusher and concentrator. Dry cobbing serves two major purposes in the new process. Its principal function is to provide large volumes of dry coarse aggregate for use in construction of tailings dams. This process rejects about 20% of the fine crusher product as tailings with a size analysis of 98% -20 mm and 50% - 10 mm. These tailings are free draining and have high frictional shear strengths-two key requirements for dam building aggregates. Fine crusher product is conveyed to a new dry cobbing building. Here crushed ore is discharged into one of two 30-minute capacity surge bins. Crushed ore is withdrawn by 12 constant speed conveyor belts; each discharges 500 t of crushed taconite into a dry cobbing machine. Each machine consists of a 3-m-long riffle splitter and two vari-

Jan 12, 1980

By R. W. Fedors, S. T. Green, R. A. Hart, D. B. Walter

Computational fluid dynamic (CFD) modeling of a potential nuclear waste repository drift may be an important tool to estimate moisture redistribution caused by natural convection within the drift. To refine and support CFD techniques, a small laboratory cold-trap experiment was developed. Results from numerical modeling of the laboratory experiment show the sensitivity of the bulk air flow rate and average air temperature within the drift to several key parameters, including various boundary condition assumptions and surrounding porous media properties.

Jan 1, 2004

Flawed mining studies have been major contributors to poor investment decisions in mining for many years, contributing to the long period of poor industry profitability. Most of the major mining houses have now adopted quite formal processes and quality standards for mining studies to reduce the potential for poor investment decisions in the future. Other organisations such as the World Bank also have specific requirements for particular types of studies, such as bankable studies. This increasing requirement for rigour and discipline means a highly structured and phased sequence of studies is now required along with the development and adoption of industry-wide standards in mine ventilation studies. New terms in the study process such as ?independent peer review? and ?hold and review? are assisting in this process. More traditional terms such as ?feasibility study? and ?pre-feasibility study? now have much more precise technical definitions. Specific standards for the ventilation components of the various phases of a mining study are proposed in this paper.

Jan 1, 2009

By J. M. Wempen

Booster fans, large underground fans, can increase the volumetric efficiency of ventilation systems by helping to balance the pressure and quantity distribution throughout a mine, reducing leakage and reducing the total power requirement. However, in ventilation systems that use booster fans there is a potential for system recirculation, the leakage of return air to intake air, and also for localized recirculation near the fan through the bulkhead and airlock doors. Air that is recirculated locally decreases the system efficiency because the quantity of air flow through the fan increases without increasing the airflow throughout the system. To understand the detailed flow characteristics of a ventilation system with a booster fan, two-dimensional computational fluid dynamics (CFD) models were developed using the software Ansys-FLUENT. Though two-dimensional models do not represent the full complexity of the flow dynamics, they do provide a good representation of the flow characteristics and they allow for a qualitative analysis of how the flow dynamics are affected by the system characteristics. The CFD models were used to evaluate how the number of booster fans, the booster fan placement, the location and geometry of the fan installation and the construction of the airlock system affect the flow characteristics and the localized efficiency of the ventilation system.

Feb 27, 2013

By James L. Weeks

Introduction This paper attempts to summarize some of the major criticisms of drug testing. Eight problems with drug testing are discussed. These are: • It does not measure something employers have a reasonable need to know, • It is a distortion of priorities, • Drug use is not known to be associated with increased risk of occupational injuries, • Drug testing is proposed as a dangerously simplistic solution to poorly conceived problems, • In the absence of safeguards, it is unacceptably inaccurate, • In the absence of treatment commitments and confidentiality protection for persons dependent on drugs, it is an unethical practice of medicine, • Drug testing is an invasion of privacy, and • It will have a negative effect on treatment of persons with drug or alcohol dependencies. Employers' need to know It does not measure something employers have a reasonable need to know. It is reasonable for employers and fellow workers to want to know if workers are functionally impaired (intoxicated) while on the job. Drug testing does not measure impairment. It measures the concentration of drug metabolities in urine or blood. Unlike measurements of blood alcohol concentration (BAC), drug metabolites are not correlated with impairment or intoxication. They indicate only drug use in the one to two weeks before a urine sample. And, in some instances, they indicate chronic use. Impairment caused by drug use, on the other hand, occurs immediately and declines rapidly within hours. Drug metabolites may linger for days afterwards. Drug metabolite concentrations in urine are a function of (Morgan, 1984; Schartz and Hawks, 1985; MMWR, 1983): • the amount and purity of drug consumed before taking the test, • when the drug was consumed, • whether the person was a chronic user, in which case a certain amount of drug metabolites would be stored in body fat and slowly released, • the person's metabolic rate, and • for metabolites in urine, any dilution effects of urine. Only the first two factors has

Jan 11, 1987

The Pogo Mine, near Delta Junction, Alaska is a new 2500 STPD gold operation. The control system of the mine and milling operations are a hybrid of DCS (Distributed Control System) control and PLC (Programming Logic Controller) control. A DeltaV DCS system serves as the main control and operation platform while the PLCs operate a multitude of vendor specific packages. The communication backbone of the DCS system is a hybrid of star and ring fiber optic topology, which provides reliability and flexibility. The communication between the DCS and PLCs is typically facilitated by serial communication. This communication insures the integrity of the whole control system.

Jan 1, 2008

By D. Brosnahan, J. Gathje

Newmont Metallurgical Services (NMS) recently acquired a Scanning Electron Microscope (SEM) with a JKMRC/FEI Mineral Liberation Analyzer (MLA). With the MLA software package, raw particle image and X-ray data can be converted into particle mineral maps and bulk and liberation data can then be calculated for minerals of interest. This type of quantitative mineralogical data can then be used for a wide variety of applications. Ore characterization with MLA can be carried out for existing or processing plants in development. MLA characterization of laboratory test products provides valuable liberation information that assists the research metallurgist in better planning and developing process treatment options for various ore types. This paper describes the use of MLA characterization in a copper flotation test program where the use of various testing options for arsenic depression was being evaluated.

Jan 1, 2007

By M. Sagheer

An 8.5-km (5-mile) conveyor has gone into operation in western Turkey to eco¬nomically transport crushed lignite from the mine area to a power plant. This conveyor has replaced trucks as the principal mode of transporting the lignite. One principal element of Turkish govern¬ment policy is the country's commitment to increase electricity supplies for mining and other industries. Lignite is an important source of electric power supply in Turkey. Production was about 48 Mt (53 million st) in 1987, amounting to more than 20% of the total power supply in Turkey. In the western Anatolia supply network, it plays a major role for power generation. Deposits are located in the Soma region of western Turkey. The lignite is of low quality, deposits are scattered, and the terrain is dif¬ficult and hilly. These conditions demand an economical and technically feasible method of transporting the raw material from mining areas to the central thermal power plant. The Soma power plant is located about 120 km (75 miles) northeast of Izmir, near the coast of Aegean Sea. An overland conveyor of a unique design has gone into commercial operation at the Soma power plant facilities of the Turkish state electricity organization, Türkiye El¬ektrik Kurumu (TEK). The conveyor re¬places truck transport to ensure economical use of the lignite deposits. Computer-aided design (CAD) added more precision, qual¬ity, and flexibility of engineering in design activities. It also helped quick realization of the project that was executed in cooperation with the German company Krupp Industri¬etechnik and the Turkish firm Gama Endüstri AS. Unique features The conveyor includes several major features rarely combined in a single flight: Overland long distance conveyor. • Horizontal curves. -Steep vertical concave and convex curves to match the difficult terrain. Down-hill conveying. Frequency converter drives with vari¬ able belt speed. Generating operation mode to backfeed the energy to the network. Layout The 8.5 km (5 mile) long conveyor takes the -200 mm (-8 in.) lignite from the primary crushing plant located near the mine to the central, final crushing plant located in the stockyard area near the power station. The drive and belt tensioning assemblies are situated near the tail end of the flight. The high voltage switchgear is housed in a room in the primary crushing plant build¬ing upstream from the conveyor flight. The frequency converters are installed in the low voltage switchgear room located below the control room within the primary crushing plant building. Conveyor design The conveyor includes two 4 km (13,120 ft) radius horizontal curves, one left-hand and the other right-hand. The minimum radii

Jan 1, 1989

Adverse ground behavior events, such as convergence and falls of ground, are some of the most significant challenges and hazards in underground mines. Our goal is to work toward mine-wide, digital, and real-time three-dimensional geotechnical situational awareness and predictive capabilities in complex underground mining operations. This will benefit operators, engineers, and management by enabling them to develop a more proactive approach to ground control. To this end, and inspired by research in the field of remote sensing and autonomous robotics, this paper assesses the potential of mobile light detection and ranging (LiDAR) data acquisition for high-frequency, high-accuracy monitoring tasks in Global Navigation Satellite Systems (GNSS) deprived underground mines. Limitations of current monitoring practices are reviewed. Relevant academic and commercial developments in the fields of indoor mobile mapping systems (MMSs) and simultaneous localization and mapping (SLAM), robust autonomous robotic platforms, and automated remote sensing data processing are highlighted, and their current shortfalls are evaluated. To conclude, the ramifications of this work for the development of future autonomous underground mine monitoring solutions are discussed.

Jul 28, 2020

By T. J. Lynch

A new class of polymeric dispersants for industrial minerals has been synthesized and evaluated. Currently available dispersants give initial low viscosities at high mineral loadings, however slurry viscosities can rapidly double or triple on standing over the first several days. The new dispersants give low initial viscosities that are more stable and maintain a lower viscosity for at least one month. The new dispersants are made possible by controlling the polymer molecular weight distributions during their manufacture such that essentially all of the dispersant is adsorbed onto the mineral surface, preventing depletion flocculation.

Jan 1, 2012

By Andrew Howard

As the mining industry moves further into developing countries in search of new resources, its role in international development is coming under increasing scrutiny. This is a trend that is likely to accelerate, along with the potential for headaches among managers in the industry. Public interest in development and environmental issues is rising as faith in “big business” falls. This has strengthened nongovernmental organizations (NGOs) campaigning for sustainable development. And it has put more pressure on banks, governments and development agencies to curb corporate misdemeanors. Developing world governments are also becoming emboldened to reject previously agreed terms they do not consider equitable. The mining industry has begun to formulate a response to these pressures but must go much further. Societal and environmental issues must move from public relations to core strategic thinking. Abiding by rules or codes is not a relevant response. Instead, genuine support for sustainable development is required. This will involve delegating the responsibility for engaging with local communities to on-the-ground staff and developing a dialogue with local stakeholders rather than conducting an initial assessment and disengaging.

Jan 1, 2006

By A. Bascetin

Waste materials caused by mining activities are an important environmental problem. Paste technology is a good alternative for waste management because it has many benefits in the aspects of environment, cost and safety. Disposal of process wastes in paste form is an attractive option for waste management, as it eliminates or reduces the risks associated with conventional methods. Due to the geotechnical characteristics of the paste, it is very similar to soil materials. So determining the geotechnical properties of the paste material is essential to durability of the paste. The some important geotechnical properties are compressive strength, porosity, shear strength, hydraulic conductivity, water content, consolidation, etc. In this study, the important parameters and the relation between them were investigated and obtained some results which will affect for optimum design of waste management.

Jan 1, 2012

By Marianne Snedeker

In January we published a questionnaire asking about the content of MINING ENGINEERING and about your interests. At the same time we hired an outside firm, READEX Inc., of St. Paul, MN, to send the same questionnaire to a sampling of about 1000 US members, selected on an nth name basis, so that we could have some preliminary numbers for the Annual Meeting in February. READEX sent us the final results of its survey in March. At that time, 525 responses of the 992 surveys sent out had been returned, for a 52.9% response, an extraordinarily high return for a low-key (no incentive for return) random sampling. On May 7, we cut off on tabulating returns from the magazine so that we could report the results to you in this issue. At that time, we had 594 questionnaires returned. Our 594 and READEX's 525 (we have assumed that relatively few people returned both), represent a 1119 return, about 3.5% of the approximately 32,000 who received the January issue of ME. About ME Through responses to the questionnaire, we were hoping to learn more about you, your interests, and how the magazine could better serve you. Those of you who responded, told us something positive-you look at or read the magazine. Of the 1119 respondents, 1068 or 95.4% indicated that they had read or looked through the November and/or December issues. Those of you who refer to the magazine once are 466 or 42.6%. Those of you who refer to the magazine two or three times are 559 or 51.1%. Those of you who refer to the magazine four or more times are 68 or 6.2%. How much time do you spend reading the magazine? Of those responding to this question: 186 spent up to 1/2 hr 16.6% 590 spent up to 1 hr 52.7% 292 spent 1-2 hr 26.1% 51 spent more than 2 hr 4.6% In an informal survey among our staff, we determined that most people spend 1/2 to 1 hr reading magazines to which they subscribe at home. Does that match your experience? Many of you, 764 or 69.4%, clip your magazine for further reference. Also, many of you, 513 or 64.2%, do not pass your copy on to another reader, indicating perhaps that you are clipping it or receiving the magazine at home. Those magazines that are passed on reach: 2 people - 159 - 20.0% 3-5 people - 95 - 11.9% 5 or more - 31 - 3.9% Answers to what portions of the magazine you find useful indicated that the top three were Industry News, feature articles, and Technical Papers; see Table 1. The "other" category included advertising-display, classified, and employment-Coming Events, product information, Washington Survey, new books, the reader service card, and Engineering Fundamentals. Of those responding, 797 or 75.3% indicated a preference for dual notation of SI (metric) with English units; 228 or 21.5% preferred all SI units; while 34 or 3.2% preferred SI with dual notation of other metric units. Based on the preliminary numbers reported by READEX for this question, the MINING ENGINEERING Committee in February voted to return to a policy of dual notation. This decision has been implemented. We asked for your appraisal of the technical level of the magazine. Of those responding, 78 or 7.4% indicated it is too technical, 147 or 13.8% indicated it is not technical enough, and 836 or 78.8% judged it to have the correct tech¬nical level. In response to the question about whether you like to read an occasional feature that is not technically oriented, 32 said no, but an overwhelming 97% (1024) said yes. Of the specific topics, 785 like history, 558 political or socioeconomic articles, 440 career development, and 373 human interest. Other topics suggested included new disciplines, mineral resources of the world by

Jan 6, 1982

By Valois R. Shea-Albin

Increasing pressure from State and Federal agencies to mitigate mining-induced subsidence damage to overlying structures has presented a unique problem to the coal industry in the western United States. Because sandstone escarpments are an environmental issue, millions of tons of coal reserves that underlie these escarpments risk being classified as unminable by regulatory agencies. At this time, the effect of subsidence on escarpments has not been well documented or characterized. The Bureau of Mines is using numerical modeling techniques to analyze escarpment response to longwall mining. Two- and three-dimensional finite element models have been constructed for a study area near Price, Utah, where longwall panels were mined near an escarpment. This status report includes preliminary results showing that the pattern of subsidence surrounding the escarpment can be simulated through numerical modeling. Models that include such structural details as joint and fracture patterns will better simulate subsidence patterns .and magnitude. By locating longwall panels strategically in relation to the escarpment, stability may be preserved throughout the mining process. Numerical modeling provides a method to analyze relatively quickly the effects of longwall panel location and resulting subsidence on escarpment stability. The goal is to provide a relatively accurate predictive tool for mine planning to determine if escarpment stability can be maintained while maximizing extraction of the coal reserves.

Jan 1, 1986

By H. Lyn Bourne

This is the fourth annual tabulation that gives mineral royalty information. The table presents previous information plus about two dozen new entries. In addition to the royalty information, some entries show the cost of purchased reserves. Last year's tabulation appeared in two issues, to accommodate all of the information. This year the format has been changed slightly so the table can be printed in one issue. This year's table presents the commodities in the same sequence as last year. Sand and gravel information appears first, followed by: crushed stone for aggregate; other stone; industrial sand; other industrial minerals; energy minerals (coal, oil shale, uranium); and finally metals. As always, a caveat relates to factors that influence the reserve values. The data should serve only as a general reference. The table is not intended to present an absolute scale of reserve costs. Several factors influence the value of mineral commodities. These factors include: • location and transportation costs (especially significant for most industrial minerals); • market conditions for both the commodity and the company acquiring the right to mine it; • quality or grade of the deposit as it reflects the amount of processing and beneficiation necessary to produce the finished product; • and legislative restrictions and conditions for mining a given material at a given site. These and other factors will influence reserve costs of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity; the location (either by state, US geographic area, or Canadian province); the cost (R for royalty and P for purchased cost); and the year in which the lease or purchase agreement occurred. The last column offers either comments or gives a footnote number for more information. The cost column requires more explanation. The units may refer to cubic yards (/yd), cubic feet (/cuft), tons (/T) (2000 lbs) or acres (/A). 1 cu yd = 0.76m3 1 cu ft =0.28m3 1st = 0.9 t7 1 acre = 0.40 ha or m2 In several cases the royalty is a percentage of the finished products, sale price and is levied against either the amount produced or the amount sold. We thank those who contributed information for the table: J. Dunn, T. Eyde, K. Loda, L. Morgan, F. Nix, H. Sorenson, and L. Williams. Several people have said they would like this to be an annual tabulation. That can happen if new information comes to the writer. What appears in the table is only a very small fraction of the cost information relative to the various commodities and the geographic areas for which there is royalty information. If you find this column of interest and possess information write or call: H. L. Bourne, c/o Neyer, Tiseo & Hindo, Ltd., 38955 Hills Tech Dr., Farmington Hills, MI 48018, (313) 553-6300. Only with new information can this become an annual and current source of reserves costs.

Jan 8, 1986

By P. R. Clifford

Phosphogypsum is a byproduct of the manufacture phosphoric acid. There are approximately one billion tons of phosphogypsum stored in stacks in northern and central Florida. The Florida Institute of Phosphate Research (FIPR) is investigating potential uses of phosphogypsum. These include using phosphogypsum as a road base material, as a soil amendment in agriculture, as a daily cover in landfills, and as a construction material. The results of this research will be presented and will be discussed in light of regulatory barriers to the use of phosphogypsum.

Jan 1, 2002

By Jacek B. Stypulkowski

This paper discusses the challenges faced by the design team of the under-river crossings of electric transmission feeders in New York City, a densely populated urban area. The under-river crossing of a 345 kV feeder was initially designed as Horizontal Directional Drilling (HDD), but was redesigned as a utility tunnel because of site con¬straints on both sides of the river. Multiple studies addressed location, available tech-nologies and costs. Multiple soil investigation phases addressed design aspects of HDD, as well as tunneling. Contractual issues varied from a design build alternative with Geotechnical Data Report (GDR) to design tender approach with GDR & Geotechnical Baseline Report (GBR).