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The 26th international APCOM symposium, hosted by The Pennsylvania State University, was held Sept. 16 to 20, 1996 in University Park, PA. Conducted about every 18 months throughout the world, APCOM symposia focus on the Application of Computers and Operations Research in the Mineral Industry. The APCOM International Council is the governing body of the symposia and determines the symposium’s locations and sponsorships. This group is composed of the nine permanent (voting) members. They include the University of Arizona, Colorado School of Mines, Pennsylvania State University, Society for Mining, Metallurgy and Exploration, Inc., Canadian Institute of Mining, Metallurgy and Petroleum, South African Institute of Mining and Metallurgy, Technical University of Berlin, Institution of Mining and Metallurgy and Australasian Institute of Mining and Metallurgy. The three nonvoting members are Moscow Mining Institute, China Institute of Mining and Rudarski Mining Institute of Slovenia.

Jan 1, 1996

By J. H. Schuenemeyer

Uncertainty estimates on coal resources were computed as part of the U.S. Geological Survey’s National Coal Resource Assessment study of more than 60 coal beds and zones in the Appalachian Basin, the Colorado Plateau, the Gulf Coast, the Illinois Basin, and the Northern Rocky Mountains and Great Plains. The estimates were made to provide zone specific measures of uncertainty on the historical categories of geological assurance, namely measured, indicated, inferred and hypothetical. Previous estimates were based solely upon distance from a drill hole. These new estimates incorporate site-specific variability and spatial correlation and indicate that there is considerable difference in variability within and between regions. Uncertainty estimates for the measured category are discussed in this paper.

Jan 1, 2001

By J. L. Huiatt

Kerosine, fuel oil No. 2, vapor oil, and fuel oil No. 6 were separated into general hydrocarbon fractions by ion exchange chromatography and adsorption chromatography. The collecting properties of these fractions were evaluated by flotation of molybdenum and copper minerals from a natural chalcopyrite ore. Paraffin fractions and aromatic fractions of low polarity produced the best molybdenum recoveries. Selective flotation of molybdenite from copper sulfide minerals was not possible with any of the chromatographic fractions.

Jan 1, 1972

By J. Hindman, E. Moeller

Vermiculite is currently mined from shallow (less than 25 m or 80 ft) surface deposits throughout the world. The largest producers are Palabora Mining of Phalabowra, South Africa (ore stock is a phlogopitemica), Xinjiang Yuli Xinlong Vermiculite of Korla, China, and W.R. Grace of Enoree, SC (ore stock is a biotite mica). Smaller operations are in Australia, Brazil, Russia and Zimbabwe. They also produce vermiculite on a continuous basis but do not export any significant amounts of product to North America. Intermittent and poorly documented production on a minor scale is reported from Argentina, Egypt, India and Uganda. Worldwide vermiculite production in 2004 increased1.7 percent to 432.8 kt (477,000 st). North American production declined, while African and Chinese production continued to increase.

Jan 1, 2005

By P. S. Baker

CRU estimates that the global supply of metallurgical grade alumina (MGA) grew by 5 percent during 2005 to a little more than 61 Mt (67 million st). About 30.7 Mt (33.8 million st), or 50.3 percent, of that originated from Oceania (principally due to the commissioning of the CAR refinery in Australia) and Latin America. In this context, Chinese production surged by 20.5 percent year-on-year to 7.7 Mt (8.5 million st) on the crest of a 17-percent rise in that country’s primary aluminium production. Meanwhile, on the demand side, there was a 6.7 percent climb year-on-year in global consumption to 62.3 Mt (68.6 million st). This reflected a healthy demand for primary metal from aerospace, construction, packaging and passenger transportation (to a lesser degree) in the United States, China, Brazil, South Korea and India. So there was an overall supply deficit of more than 1.2 Mt (1.3 million st). This, combined with an 18.3-percent diminution in closing stocks (down to 35 days of requirement), lifted the average spot price of MGA by 17.6 percent year-on-year to US$448/t (US$406/st).

Jan 1, 2006

By G. A. Campbell

This paper considers the international market trends of the rare earths and how they are strongly influenced by the by-product/co-product nature of their mining and processing. The two main economic minerals for the rare earths are bastnasite and monazite. Monazite is primarily a by-product of mining ilmenite and rutile and is affected by changes in these markets as well as the presence of thorium. Bastnasite is a by-product of mining iron ore in China and a stand-alone product in the USA. The paper will use conceptional relationships and empirical data to delineate the various by-products/co-products relationships and how they determine observed international market behavior.

Jan 1, 1996

By J. F. Brune

"Re-occurring face ignitions in U.S. coal mines are concerning and require a closer look at air quality monitoring systems and practices employed in these mines. The explosion disaster at the Upper Big Branch mine in West Virginia in 2010 caused 29 fatal injuries and was largely caused by inadequate water sprays and inadequate ventilation monitoring. In this comparison, the author compares ventilation system monitoring in Australian, German and U.S. underground coal mines and makes recommendations for improvements and best practices. Mines in Germany and Australia are adhering to more stringent requirements for monitoring air quality and quantity and for monitoring water spray systems on cutters to prevent frictional ignitions. Air quality should to be monitored for sufficient oxygen, toxic gases, explosibility and for fire gases indicating a potential fire. Ventilation monitors must also confirm that sufficient quantities of air are available. Fully automated, continuously recording atmospheric monitoring and alarm systems are established practices in Germany and Australia and should be mandated for U.S. mines as well, in addition to the current, regular spot inspections of the ventilation system by certified mine examiners. BACKGROUND: METHANE EXPLOSIONS, FACE IGNITIONS AND NEED FOR AIR QUALITY MONITORING Accumulations of methane in face areas of underground coal mines frequently lead to ignitions that can cause burns, traumatic injuries and, in the case of the 2010 Upper Big Branch disaster, cause major explosions with multiple fatalities. Table 1 shows the number of reported face ignitions in U.S. coal mines between 2010 and 2014, based on statistical data published by MSHA (MSHA 2010 – 2014). Although there appears to be a downward trend in such ignition incidents over time, ignitions continue to occur with some regularity; and each ignition may cause a potentially catastrophic mine explosion.Per regulation, all U.S. coal mining machinery, continuous miners and longwall equipment, is outfitted with continuously monitoring methane sensors wired to cut power to the equipment as the methane level exceeds 1%. Face ignitions keep occurring because these sensors are usually not positioned in sufficiently close proximity to the coal cutting drums or to the freshly exposed coal face where the methane is most likely released. Therefore, methane may accumulate in explosive concentrations near the coal face and the cutting drums long before the gas concentration reaches the 1% level near the monitor and creates an alarm."

Jan 1, 2016

By P. Mills

More than 95 percent of all the barite mined and produced is used in the petroleum industry as “drillers mud.” The remaining barite is used in the industrial and medical markets. Therefore, the amount of drilling activity is a good indicator of the health and growth of the barite industry. The four major barite-producing countries in the world are China, the United States, India and Morocco. In 2005, the average number of drilling rigs exploring for oil and gas increased by about 15 percent over the average number in 2004. This increase in oil and gas exploration has resulted in a higher demand for barite and an increase in barite production.

Jan 1, 2006

By D. Gignac, P. A. Studemeister, H. Koza

Two epiclastic horizons in an Archean volcanic sequence host the gold occurrences on the Dunraine property near Wawa, Ontario, Canada. The Grace horizon of cherty and pelitic tuff strikes north-northwest and dips east. Native gold occurs with arsenopyrite in bedlike and podlike bodies of quartz lenses and stringers set in a pelitic matrix. The Parkhill horizon of lithic graywacke with associated flow-breccia strikes southwest and dips south. Native gold occurs with minor sulfides in similar bodies of quartz erratic within the Parkhill horizon. The auriferous bodies occupy paleotopographic channels and troughs within the two horizons. The former producers are the Parkhill mine with 1689 kg (54,300 oz) Au, Darwin mine with 473 kg (15,200 oz) Au, and Van Sickle mine with 48 kg (1536 oz) Au between 1902 and 1944. The gold occurrences are syndepositional with the host volcanic sediments laid during a pause in explosive volcanism. Fumaroles along steep gullies on the flank of a subaqueous volcanic center precipitated aprons of auriferous silica-sulfide mud. Downslope slumping resulted in exhalative debris flows; gold concentrated in flexures and depressions along stumpage channels. Renewed explosive volcanism covered the auriferous sediments with pyroclastic tuffs, arresting the slumping of in situ fumarolic deposits.

Jan 9, 1985

By J. Brooks

The use and application of shotcrete for ground support in the Asia Pacific Region is as diverse as the countries that make up this region. This paper will attempt to describe the many methods used on selected projects within that region. The project description(s) will include project logistics, equipment, mix design, products and application methods utilized along with specifications and performance results (where available). The author will attempt to reach a conclusive opinion on the success, or nonsuccess, of the various shotcrete methods employed and the development of shotcrete within the Asia Pacific Region.

Jan 1, 1999

By B. Swarbrick

Today’s mining occurs in a dynamic world of conflicting objectives. Mining companies have to look further than a traditional cash flow analysis to determine the potential value of developing a mine. In particular, proposals for new mine developments undergo rigorous scrutiny by a variety of stakeholders including regulators, NGO’s, and the local communities. From a business risk perspective, how mining companies address stakeholder concerns can have a dramatic impact on the success of the project. In today’s mining environment mining companies must continue to ‘walk the talk’ to stay in business, particularly during downturns in the business cycle. Falconbridge’s Raglan Mine is an example of a project that was successfully developed in a region that is sensitive from many perspectives, including environmental, socio economic, and regulatory. Close working relationships with local stakeholders along with strong environmental management systems are necessary elements of continued success for the project.

Jan 1, 2000

By M. SIDDARAJU, Rameshwar Sah, Satendra Kumar, Arvind Jaiswal

The study explores a novel process to sinter porous iron ore with improved productivity and quality. The iron ore is pre-processed with calcined lime to temporarily close pores, preventing water absorption during granulation. This enhances reaction kinetics and early slag formation during sintering, resulting in significant improvements in sinter productivity, product yield, and cold strength property.

Feb 28, 2022

By J. L. Huiatt

The U.S. Bureau of Mines and Great Salt Lake Minerals and Chemical Corp. developed a froth flotation process for concentrating potassium salts from Great Salt Lake solar evaporites containing about 5 percent K. The crude evaporites, which were predominately halite (NaCl) with smaller amounts of kainite (KCl.MgSO4.2.7H20) and schoenite (K2SO4MgSO4.6H20), were conditioned in a saturated brine solution, thus converting nonfloatable kainite to the floatable mineral schoenite. Schoenite was then selectively floated with a medium-molecular weight fatty acid. Continuous small-scale pilot plant testing indicated that 80 percent of the potassium could be recovered from the crude evaporites in flotation concentrates assaying about 11 percent K.

Jan 1, 1975

By John Reilly

The author?s paper at RETC 2007, ?Alternative Contracting Methods? addressed strengths and weaknesses of DBB+DB and introduced Construction Manager/General Contractor (Portland model) and Alliancing (Australian model). Considerable interest in these was expressed by several public agencies at that Conference and at the presentation. The author is assisting the Washington State Department of Transportation (WSDOT) and the Toronto Waterfront Revitalization Corporation (TWRC) with possible implementation of Alliancing. WSDOT is evaluating ways to do this and is considering a delivery methodology, under existing Legislation, based on the CMGC Portland model with incentives and disincentives, moving towards Alliancing. This paper will build on the 2007 paper and update implementation considerations.

Jan 1, 2008

By R. P. Proulx

The Meikle Mine is a high grade, underground goldmine utilizing primary-secondary longhole open stoping with delayed backfill to produce 2700 tpd(3000 stpd) of ore. Hot and reactive ground conditions were encountered early on in the mine life. Ground temperatures up to 166°C (330°F) were measured. In the early stages of mining, the mine experienced premature detonations using different explosive products. The learning curve to safely mine this high-grade gold deposit in hot and severely reactive ground was indeed very steep. Currently, the Meikle Mine uses a special buffered bulk emulsion in all blasts to address hot and reactive ground concerns. In addition, exacting procedures are also followed to ensure safe work with explosives. The combination of new explosives technology and strict loading procedures permits high mine productivity with the highest degree of safety.

Jan 1, 2000

By G. C. Adams, J. H. Fowler

Canada's gypsum industry began more than 200 years ago in the Maritime provinces when farmers attempted to supplement their incomes by selling "land plaster" to traders bound for the United States. Rising from such humble beginnings, gypsum now contributes significantly to the economies of nine of Canada's 10 provinces. Thirteen open-pit and three underground mines produced a total of 8.4 Mt (9.3 million st) of crude gypsum, and 17 processing plants manufactured 2.5 Mt (2.8 million st) of finished products in 1985. Recent economic growth in North America has resulted in steady increases in gypsum production. However, competition from foreign producers and by-product gypsum pose a growing threat to Canada's gypsum mining industry.

Jan 1, 1987

By A. Anani

The goal of hot mix asphalt (HMA) design is optimal material blending to meet Superpave specifications. HMA cost minimization has being modeled as linear programing (LP) (Awuah-Offei et al 2011) and mixed integer LP problems (Brown et al, 2012) and solved with commercial software such as LINDO and CPLEX. Often these software, which are designed to solve general optimization problems, have licenses that cost thousands of dollars. The objective of this study is to develop a novel solution algorithm to the HMA optimization problem presented by Brown et al. (2012), which will negate the need for expensive commercial packages and is specific to this problem. This novel algorithm is based on the branch and bound algorithm for solving mixed integer problems. The algorithm is incorporated into a software package with an easy-to-use graphical user interface. The developed algorithm is validated using a real-life HMA problem. Using this solution algorithm will save companies thousands of dollars, otherwise used to purchase software licenses.

Feb 23, 2014

By M. Li, J. D. Miller

During the past decade, considerable effort has been made to develop improved flotation strategies for the sedimentary phosphate resources from Florida, particularly the dolomitic phosphate resources. New flotation equipment and alternate flotation strategies have been evaluated. These developments are reviewed for both traditional siliceous resources and future dolomitic resources. Most process strategies involve variation in the reagent sequence and/or the use of depressants/dispersants. Further research and development efforts in flotation technology are needed to increase flotation plant capacity by elimination of the conventional double float process, to improve the recovery of coarse phosphate, and to achieve the desired selectivity with respect to carbonate minerals, particularly dolomite.

Jan 1, 2000

By T. S. Bomar, C. J. Wood

Heavy media cyclones (HMCs) are efficient, high-tonnage devices suitable for upgrading run-of-mine coal in the 50 to 0.5 mm size range. Unfortunately, industrial HMC circuits are often not optimized due to problems such as incorrect operating pressures, poor feed distribution, excessive media contamination, mismatched components, and improper density control. To avoid these problems, operating guidelines have been provided in this article that are useful for optimizing the performance of HMC circuits. The validity of these guidelines has been assessed by means of density tracer tests carried out at several coal preparation plants.

Jan 1, 2002

Like the Summer Olympics and U.S. presidental elections, MINExpo comes along once every four years. More than 35,000 people attended the last MINExpo and there is talk that there will be more this time. Just about every company that has anything to do with mining, 1,822 to be exact, will exhibit their wares at the show, but it is the ones rolling in the massive equipment that make MINExpo the show that it is. The following is a glimpse at some of the companies and equipment that you can expect to see at this year?s MINExpo.

Jan 1, 2012