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By M. Javier

Defining the concept of sustainability is an important step for industry and society. It is necessary in order to clarify what it means when debunking the many misinterpretations pervasive in different levels of anthropogenic activities. Essentially, the extractive industry has a harvest of differences. Mining involves the extraction of natural resources which are finite, exhaustible, non-renewable, unsustainable, and pay only once. It is remarkable that the definition of sustainability that we will shortly arrive at has totally different characteristics from the definition accepted throughout society. We categorize nature as having its own destiny which is controlled by its own rules and principles and its own society, and is part of nature; therefore, society depends on nature and not vice versa as the initial focus. To society there are no conditions to humanize nature but only respect nature?s rules. It was a challenge to find simplicity for this task not only for the definition but also for the explanation of this concept specifically, to answer the question, ?what is the true meaning of sustainability?? Finally, we are also able through this definition to provide fuel for wide discussions and stimulate critical thinking to improve such a concept. As a result, we present this definition as the tool for society today and for future generations.

Jan 1, 2012

By H. Walqui

The Empire concentrator was built in four stages, with the latest stage accounting for 50% of the overall plant capacity. Over the past 5 years, the average throughput of the three grinding lines has decreased by 50 LTPH (15%) without significant changes in ore characteristics and despite the addition of secondary grinding capacity to supplement the existing pebble mills that are the constraint of the grinding circuit. This paper discusses the different areas under study that are aimed at optimizing grinding circuit utilization which includes improving system logic, pebble crushing operation and pebble mills operation.

Jan 1, 2009

By J. J. K. Daemen

Mining Engineering education is in trouble, if not in crisis. The most visible signs are the decrease in the number of programs that offer the degree, and the continued difficulties in attracting students to the discipline. Unless these trends are reversed, the future of the profession is uncertain, at best. Remedies have been proposed, and some are drastic. They range from consolidating mining engineering education into one or two national schools, to cooperative regional programs, to distance education programs, and to proposals to limit mining engineering to a graduate degree or specialization only. These alternatives deserve serious attention and merit discussion. I hope that one alternative that will remain on the table is the classical and traditional “School of Mines”. A reasonable number of such schools are needed to provide the educational diversity and the critical mass to maintain accreditation and professional registration for their graduates. Most importantly, such an approach is most likely to assure the continued existence of mining engineering as a profession. It also provides the best educational framework to teach mining engineers. However, such Schools are vulnerable, highly susceptible to university budget pressures, and probably can survive only with strong external support.

Jan 1, 2004

By Karen Mikkola, Gerald Luttrell, Jaisen Kohmuench, Glen Oswald, Michael Mankosa, Tracy Westerfield

Hydraulic separators are commonly used for particle size classification and gravity concentration of minerals and coal. Unfortunately, the efficiency of these processes can be quite low due to poor equipment design and variations in feed consistency. To help alleviate these problems, an industry-driven R&D program has been undertaken to develop a new generation of hydraulic separators that are more efficient and less costly to operate and maintain. Two of the most promising technologies, the CrossFlow and HydroFloat separators, have now been tested at industrial sites. The data obtained from these sites have been used to illustrate the potential performance improvements that can be realized through the application of these high-efficiency separators.

Jan 1, 2005

By Eric Eisold

The Wachovia Headquarters and Arts and Cultural Campus project in Charlotte, NC includes a 1.5 million square foot, 48-story office tower, two museums, an Afro-American cultural center and a 1,200 seat theater for the performing arts. Public access to the Cultural Campus is through two pedestrian tunnels constructed under city streets connecting to parking garages. The 5.7 m wide by 4.7 m high mined tunnels were procured through a design-build contract. The tunnels were designed as initial/final shotcrete linings with a sprayed water barrier sandwiched between layers of shotcrete. In addition, the mix design was supplemented with a cementitious admixture to develop internal water resistant properties in the shotcrete.

By S. Ersayin, I. Iwasaki

Application of a magnetic field was shown to be effective in controlling iron losses in pilot-scale cationic silica flotation in the processing of magnetic taconite concentrates. The design of a magnetic field distribution device and batch flotation test results using a 1.42m3 (50 cu. ft.) WEMCO cell are reported. Major losses of iron units in froth products were in the -25µm (500 mesh) fraction, and the application of a magnetic field decreased the flotation of fine magnetite, thereby improving the selectivity of separation. The “as received” sample was sufficiently magnetized and no further benefit was gained by magnetizing treatment. Selectivity was somewhat adversely affected by demagnetizing the sample, though its effect was minimal due to the magnetic field. The device is simple in construction, low cost and may be installed readily in existing equipment.

Jan 1, 2002

Many of the world?s largest existing mines are considering substantial step changes in production volumes, compensating for declining ore grades while trying to address increases in world demand for resources. The natural configuration of coal deposits allows for many mine development openings along the strike to access the ore body and thus increase volume. Similarly, with iron ore the nature of the deposits means that additional capacity can easily be added by opening up new mesas and providing extensions to infrastructure. On the other hand most of the non-ferrous metaliferous deposits form vertically and additional extraction volume comes from increasing depth. Underground mining from the base of the strata allows for large extraction rates, but block or panel caving operations develop at rates dictated by the geophysics of the overlying strata and the need for massive tunnelling developments to establish sufficient extraction points for high volumes. For really big mine production capacity, open cast mining still allows the easiest development of more massive mining techniques. But there remains the question of whether there are limits to how large an open cut mine can become in terms of throughput?

Feb 27, 2013

By Cory Dippold, Michael Mett, Jérôme Steinkühler, Kristi Latimer

For decades, tunnels of all types have been a significant part of our infrastructure. In particular, water tunnels carry millions of gallons of fresh water every day to major metropolitan areas and surrounding communities. As a critical piece of public health infrastructure, it is important to inspect the condition of these tunnels regularly to ensure reliable and continuous operation. A specific challenge with water infrastructure is that it’s often difficult or impossible to shut down the system for long periods of time to perform the needed inspections. The latest method of tunnel condition assessment is the use of hybrid reality 3-D scan data. Photogrammetric and LiDAR based 3-D data ensure a reliable and objective view of tunnel conditions. The data can be used to support a detailed digital inspection including the compilation of databases that consist of a wide variety of deficiencies such as cracks and spalls within the structure. Mott MacDonald, a design engineer company worked closely with Dibit, used a 360-degree scanning system to collect high-resolution photogrammetric and LiDAR data on a recent project involving a water tunnel. The allows for full 360-degree coverage of the tunnel surface including a water covered invert. It operates at walking speed and ensures a fast and reliable data acquisition which can reduce the time of tunnel shutdowns. Several allocated inspection weeks can reduce to few days, with the final work product being a higher quality and more complete deliverable than traditional inspection methods would have provided. The true-color 3D-model has a photo resolution of 1 × 1 mm (0.039 × 0.039 inches) which makes cracks visible with a width of down to 0.3 mm (0.011 inches). The assessment of water tunnels, its technical challenges and the results of the 3D-tunnel inspection case study are illustrated and described in this publication.

Dec 1, 2022

By R. L. Grayson, J. R. Warneke

The mining industry has searched for a message that will resonate with the public while focusing on the industry’s positive contributions to society. Thus far environmental groups remain unconvinced, and the public is still largely uninformed. In the authors’ opinion, a number of recent events and experiences have converged to help shape a more effective public communication on mining’s important role. This paper presents a fresh and cogent perspective on coal’s role in sustaining society by anchoring the message in a transparent material flow analysis that links coal’s impacts across a broad range of social and environmental aspects.

Jan 1, 2006

By D. W. Rich

An environmental management system (EMS) is a key part of a company?s environmental stewardship. Procedures and practices to continually improve environmental performance can provide great benefits in operating the company. Managing site environmental quality data is a key component of this. An environmental data management system (EDMS) is an important element of the EMS for mining and other projects, providing project staff with the information that they need to make decisions that can have a significant impact on public health. Improvements in computers, data communications, and transfer formats have made it much easier to implement an integrated EDMS program for gathering, managing, selecting, and displaying data from the field and the lab. Software now lets users define sampling plans, create files for field data entry, and print Chains of Custody. Laptop and handheld computers facilitate field data entry and may provide automated communication back to the office. Most labs can now create usable electronic data deliverables. QC checks and limit comparisons can be largely automated. The result is organized data that can be efficiently used for reporting, graphing, and mapping, to better understand project issues.

Jan 1, 2009

By Tim O’Neil

“America’s mining industry brings good jobs to communities across America and provides the energy, minerals and equipment that are vital to our economic security and our way of life.” That was the surprise videotaped greeting from President George Bush at the official opening ceremony of MINExpo 2004in the Las Vegas, NV Convention Center. Jack Gerard reinforced the upbeat mood at MIN-Expo. He praised Nevada Gov. Kenny Guinn for his support of the mining industry, the state’s largest manufacturing sector. Gerard is the president and chief executive officer of the National Mining Association, the sponsor of MINExpo 2004.

Jan 1, 2004

By W. Burger

Mechanical excavation methods can significantly improve excavation performance and labor safety compared to drill and blast operations. Herrenknecht has developed a mechanized shaft sinking method for soft and medium strength rock. This system combines innovative technologies which allow simultaneous excavation, removal of cut material and the installation of rock support. This Shaft Boring Roadheader ?SBR? is flexible in diameter and can be used in shafts with changing diameters and different shaft support requirements for depth up to 2,000 m. During regular excavation personnel are not required to access or work on the shaft bench. The boom used to cut the shaft profile is based on roadheader technology.

Jan 1, 2012

By William R. Yernberg

The combined 78th Annual Minnesota Section of SME Meeting and 66th Annual University of Minnesota Mining Symposium was held April 19 and 20, 2005, in Duluth, MN. More than 300 mining professionals, including engineers, executives, mining managers and suppliers, from throughout the United States and eastern Canada attended the meeting. This year’s theme was “Global Demand: A Window of Opportunity.” The meeting included a keynote address, technical presentations and a trade show. The atmosphere at this year’s meeting was upbeat. The iron ore mining industry in Minnesota is experiencing one of its biggest turnarounds in history. Because of greater demand, iron ore prices increased 20 percent during 2004 and 71.5 percent so far in 2005.

Jan 1, 2005

By R. Steele

In addition to compliance with government emissions and reporting requirements, mining and mineral processing companies are increasing energy efficiency to reduce costs and become more competitive in the global marketplace. One of the major obstacles to identifying opportunities for increased energy efficiency is the lack of readily available data on energy use, and more importantly the energy use linked to production data, that identify energy reduction opportunities. As well as energy reduction, mining and mineral processing companies often struggle with the prediction of energy use, and are often penalized for under or over forecasting. Once again, it is the lack of timely information that makes this prediction difficult. This paper looks at expanding the use of a Manufacturing Execution Systems by integrating with Energy Solutions. This will provide automatic, timely information, at a granularity that makes it easier to identify energy reduction opportunities, reduce energy costs, and better predict energy use in a mining and mineral processing operation.

Jan 1, 2011

By Steve Kral

Not too many years ago, mining was in one of its cyclic down-sides. This forced mining companies into some innovative thinking to bring down the costs of production. And they have. Mining equipment and processing plants have become more efficient, mostly due to technological advances. The mining industry is now in a boom period, one that some analysts believe can sustain itself. But even with higher commodity prices, sky-rocketing energy costs and the costs associated with environmental and reclamation regulations have not allowed all mines to reach their full profitability potential.

Jan 1, 2006

By A. D. Nicholson

This paper presents an approach to quantitatively calculate the neutralization of acid by silicate minerals, based on the chemical kinetics of acid reacting with silicates. This approach incorporates incongruent dissolution mechanisms and the effects of silicate iron content on net acid consumption, and offers guidelines for considering the extent to which specific silicate minerals will react. This approach differs from previous methods of estimating silicate buffering: it is based more on the fundamental chemistry of acid generation, and less on potentially misleading empirical measurements of acid neutralization.

Jan 1, 2002

By C. C. Hamilton, G. R. Lane

Traditionally, mineral sands are evaluated by preparing several mineral products using a combination of heavy liquid-, magnetic-, and electrostatic methods. Whole-rock assays (WRA) are then conducted on ilmenite, rutile and zircon products in order to determine trace element contents, which may affect project feasibility. Combined methods can be time consuming, expensive and even outdated due to the use of banned and toxic chemicals such as clerici solution. Coupled with large field-sample quantities, these procedures can potentially introduce unacceptable sampling and related errors. Modern mineralogical analysis techniques can provide complete mineralogical inventories on a single THM product, reducing the amount of processing involved in satisfactory characterization of early exploration samples. A small exploration sample can be processed to produce a small THM concentrate using readily available gravity/density methods. In turn, the THM product is submitted for Whole Rock Analysis (WRA) and mineralogical inspection by X-ray diffraction (XRD), and microscopic evaluation. Modal mineralogy and textural data can be determined using optical methods, automated image analysis, and scanning electron microscope (SEM) based systems. Benefits of automation are reproducibility and the capability of rapidly analysing thousands of particles as opposed to manual optical methods. Automated systems include the use of Automated Digital Image Analysis (ADIS), and SEM-based systems such as the Mineral Liberation Analyser (MLA) and QemSCAN. For detailed mineral chemistry, microanalysis techniques ranging from electron microprobe (EMPA) to Secondary Ion Mass Spectrometry and Laser Ablation Mass-Induced Coupled Plasma-Mass Spectrometry (LAM-ICP-MS) are used. Examples of these automated and analytical methods are presented. ADIS at SGS-Lakefield Research uses optical characteristics to identify and measure mineral species in THM samples; rutile, pseudorutile, ilmenite and leucoxene can be distinguished. Analysis of a single THM product provides bulk modal mineralogy and grain size distribution of particles and the individual mineral grains. Textural information is also obtained detailing mineral associations as well as degree of alteration. Where textural and chemical resolution renders mineral identification ambiguous, SEM-based methods offer better resolution. Examples of this ambiguity are shown in this paper, which leads to QemSCAN as the preferred method where within-grain variability is concerned. Sampling and measurement strategies are followed to meet study objectives, providing a value-added framework for a sequential, cost-effective strategy, which will meet due diligence and bankable accreditation criteria. Studying a THM product by electron microprobe and LAMICP-MS may reveal potential fatal flaws related to mineral chemistry. Low detection limits in the range of 200 to 500ppm are possible using electron microprobe analysis for suitable matrixes (U, Th in zircon). For the detection of ultra low level elemental contaminants, LAM ICPMS is the most accurate method of evaluation. Elements including U, Th, La, Ce, Nb, and V in Ti-minerals can be determined down to 50 ppm.

Jan 1, 2005

By S. Assemi

Interaction forces between a hydrophilic silica particle and an air bubble were measured by atomic force microscopy using simplified model systems with deionized water and dilute KCl solutions. Contributions from the hydrodynamic force were minimized by using a low piezo speed. Particle-bubble separation distance and the bubble spring constant were calculated from linear regression of the piezo extension versus cantilever deflection. The bubble surface potential was then estimated from fitting the AFM-measured forces to the Hogg-Healy-Fuerstenau (HHF) model, using the surface element integration (SEI) method. Surface potentials obtained for the bubble at a low applied force were comparable with the literature data, suggesting that the simplified model used here can give a reasonable estimation of the bubble surface potential under moderate applied forces. Interaction forces between a silica particle and an air bubble were also measured at different locations on the air bubble surface. The force curves obtained at the edges of the bubble fitted very well to the theoretical force curves regardless of the applied force, while curves obtained at the center and halfway to the center, were more difficult to fit, in particular at higher applied forces (> 13 nN), suggesting that force curves obtained at the edges of the air bubble might be less prone to deformation effects.

Jan 1, 2008

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

The SFR system utilizes a skimmer or extractor placed at or near the slurry-froth interface where there is a higher concentration of valuable mineral particles. With assistance of hydrocyclones, it is possible to classify the extracted particles into coarse and fine particle streams, that can be handled separately. It also allows the coarser solids to be separated from entrained low-value fines. The first test results with the SFR system significantly improved both coarse and fine particle recovery in a flotation cell. The SFR system was tested in the flotation circuit at a copper-moly concentrator, and the results show that the use of the skimmer has huge potential to increase the froth recovery (Rf) of both molybdenum and copper.

Jan 1, 2012