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By William Gleason

"Sluggish prices for commodities and a glut of oversupply of many commodities did not stop the world’s largest mining equipment makers from showing off their latest and greatest machines and technology starting with the world’s largest equipment trade show, bauma 2016 in Munich, Germany.From April 8-14, an estimated 580,000 visitors from 200 countries visited the show that featured 3,423 exhibitors from 58 countries. While primarily a show for construction equipment, the mining footprint has grown over the years. Among the largest exhibits was that of Liebherr, which brought more than 100 products, had an outdoor exhibition stand, a stand for the components division and a career stand under the motto “Be Part of Something Bigger.” One of the biggest aspects of the exhibit was its mining products where the company staged the first-ever professional table tennis match in the 130 m3 (170 cu yd) dump body of the T 264 mining truck. The top German players Timo Boll and Patrick Franziska with their trainer Jörg Robkopf faced Austria’s singles world champion from 2003, Werner Schlager, and the reigning Team Europe champions Chen Weixing and Stefan Fegerl.“Bauma 2016 was an absolute success for Liebherr. With this year’s appearance we were once again able to show our innovative strength, performance and technological diversity to a very large and international audience from the industry. We conducted interesting discussions with numerous customers and partners from various countries and discussed new projects,” said Stefan Heissler, Member of the board of directors of the Liebherr Group.Likewise, Caterpillar, the world’s largest maker of construction and mining equipment had a large presence at the show with more than 60 products and 12,000 m2 (129,000 sq ft)of exhibit space. Among the iconic yellow mining equipment that was on display was the 6015B hydraulic mining shovel."

Jun 1, 2016

By R. Hedin, M. Dunn

The Pennsylvania Department of Environmental Protection (US EPA 319 program) provided funding to aid a public-private effort in the installation of an environmentally-friendly system to treat abandoned mine drainage at Jennings Environmental Education Center (Pennsylvania Department of Conservation and Natural Resources). Through this cooperative effort among state and federal agencies, mining, excavation, and environmental companies, college and home school students, Girl Scouts, and volunteers, a successful multi-component passive system, readily accessible for upgrades and public education/research activities, was built. 90 people were directly involved in construction of this award-winning system and about 1000 people annually benefit from the educational opportunities.

Jan 1, 2002

By Don Stevens

The Denali Prospect (147° 08' 20" W, 63° 08' 50" N) is located on the south flank of the Alaska Range in the Clearwater Mountains in south central Alaska. (See Figure 1). The mineralization was discovered in 1963 and surface explora¬tion began the following summer. Surface trenching and diamond drilling were used to locate and sample the mineralized zones. In 1969, an adit totalling approximately 1400 feet was completed. In 1970, a -15% grade decline approximately 1800 feet long was completed. Further diamond drilling was done along with both underground programs. Although much work remains to be done to properly evaluate the prospect, results from all the work to date are quite encouraging. This paper will consider the geology of the prospect and the surrounding area, some- aspects of the geochemistry of the sulfides, and the origin of the sulfide deposits. This paper includes data from this writer's Ph. D. dissertation, "Geology and Geochemistry of the Denali Prospect, Clearwater Mountains Alaska" from the University of Alaska and subsequent work.

Jan 1, 1972

By S. Mukusha

Electronic spreadsheets are the most common and readily available software applications for analyzing and modeling quantitative problems. Spreadsheets can offer a vast array of opportunities for the analysis and modeling exercises encountered in the field of geomechanics. This study explores the potential for using spreadsheets of in the practice geomechanical engineering. The study also examines some of the barriers to widespread use of spreadsheets. Best practices and guidelines for overcoming potential pitfalls are discussed and highlighted through a case study.

Jan 1, 2000

By Louis Schaarschmidt, Helmut Mischo, Ibrahim Alsalamin

In order to store high-level radioactive waste underground, the German repository concept considers clay, crystalline and salt formations as suitable host rock materials (National Citizens’ Oversight Committee, 2024). The current research projects of the Chair Underground Mining Methods at TUBAF (Technical University Bergakademie Freiberg) in nuclear waste repositories mainly focus on storage within salt formations. In this scenario, the high-level radioactive waste is supposed to be packed into specifically designed containers and then transported underground and emplaced in horizontal storage drifts. The residual temperature of the radioactive waste leads to the question if there are optimization possibilities for waste handling, the storage and the long-term emplacement of such high temperature level waste. A deeper understanding of the heat transmission from the container into the host rock might lead both towards possibly shorter surface interim storage times as well as size optimization possibilities of the repository itself. TUBAF has conducted research that successfully proved that an optimized container positioning yields more favorable thermal patterns and can be achieved with conventional mining equipment.

Feb 1, 2025

By G. Deschenes, W. Yen

Ammonium thiosulphate is a non-cyanide lixiviant for gold leaching. The major problem is the high reagent consumption. A combination of 0.3M (NH4)2S2O3, 0.03M CuSO4, 3M NH3 was used to leach a copper-bearing gold ore at pH 10.2 for 24 hours. 30 kg/t of thiosulphate was consumed. Oxygen and copper species were found to be responsible for thiosulphate decomposition. The thiosulphate consumption could be reduced to around 17 kg/t by adding chelating agent, reducing copper sulphate concentration to 0.001 M and replacing CuSO4 by NiSO4. The increase of pulp density might reduce the thiosulphate consumption to around 17 kg/t. By regulating the oxygen supply, the thiosulphate consumption could be reduced to 10 kg/t.

Jan 1, 2002

By H. Do

In flotation, hydrophobic particles are selectively collected by air bubbles, and the bubble-particle aggregates enter the froth phase. However, less hydrophobic particles drop off from the froth phase, while more hydrophobic particles are recovered. Thus, the froth phase provides an important cleaning mechanism. In the present communication, the froth-phase recovery process has been modeled by considering particle retention times and the carrying capacities of bubbles. The model predictions are compared with the experimental data reported by Seaman et al. (2006). The results show that the froth-phase recovery varies with particle size, particle hydrophobicity, and bubble coarsening.

Jan 1, 2008

By Steve Kral

San Francisco, CA will host about 1,500 tunneling and underground construction professionals from around the world during the biannual Rapid Excavation and Tunneling Conference (RETC), June 19-22. These professionals are gathering in a city that has seen much under-ground work throughout its history. And, today, the San Francisco region has more than $4.6-billion in tunneling projects under way. The RETC will include three-and-a-half days of technical programming, complete with proceedings, two short courses, two field trips and a host of social activities. In addition, the accompanying exhibit has attracted 127 exhibitors in 152 booths, an RETC record. The following is a brief list of activities that will take place during the conference. A more complete program is provided in the official showguide that is bound into this issue of Tunneling & Underground Construction.

Jan 1, 2011

By Arthur W. T. Grimley

Hydraulic coal mining is being successfully practiced in China, U.S.S.R., Japan and Canada and in each country, excepting Japan where suitable sites are not available, the system is being expanded to either existing conventional mines or new mines. Productivity levels and economics at these mines are in all cases better than the productivities achieved in conventional mines in the same general localities. In the U.S.S.R. face productivities approaching 50 tons per man shift have been reported while in Canada the latest statistics show average face area productivity levels are in the region of 200 tons per man shift production monitor. In the United States hydraulic mining has not been actively pursued to the same degree and consequently there are no full scale hydraulic coal mines in operation or construction. Because many of the coal measures in the Western U.S.A. are generally somewhat similar to those being successfully hydraulic mined in Western Canada and parts of Siberia it is realistic to believe that successful hydraulic mines can be designed and developed in the Western U.S.A. Particularly if the vast technological base that already exists is used to improve on other people's ideas, systems, methods and equipment.

Jan 1, 1983

By Ken Mathers, Tom Conley, Jim Rozek

The Melbourne City Link Tunnels have been constructed through a BOOT process, the largest undertaking in Australia to date. Tolling commenced on the 1.6 kilometer Domain tunnel in April 2000, and the 3.4 kilometer Burnley tunnel December 2000. The project was delivered by design construct contracting and under ISO 9000. There were a number of major challenges in completing the tunnels, including much higher than expected groundwater infiltration, hydrostatic pressures greater than 6 bar, and unique design and construction applications required to prepare the tunnels for service. This paper covers the end play and final delivery of the tunnels.

Jan 1, 2001

By W. Pawlos, A. Bakalarz, M. Duchnowska

This paper presents the results of an investigation into the influence of hydrodynamics on a preflotation process for the copper sulfide ore from the Fore-Sudetic Monocline deposits in Poland in a flotation machine. The main aim of the preflotation stage for Polish copper ore is to remove the easy-to-float organic matter — organic carbon — that causes serious problems in metallurgical processes. The organic matter is connected with the presence of shale ore. This paper describes the preflotation experiments conducted to investigate the effect of various stirrer speeds. The upgrading selectivity of copper and organic carbon were analyzed and compared. The results show that the effectiveness of separation between organic carbon and copper decreases with increased stirrer speed in the laboratory flotation machine. The more intensive the mixing of the flotation suspension, the lower the selectivity of the preflotation experiment. Lower stirrer speed probably provides lower mechanical entrainment and flotation of copper minerals.

By William J. Miles

The markets and applications of Wyoming bentonite deposits are primarily determined by the functional properties of a bentonite ore which results from the unique mineralogy and chemistry of each deposit. Commercial bentonite products contain sodium montmorillonite as the major mineral component, with minor concentrations of accessory minerals such as quartz, opal (silica hydrate), mica, feldspar, gypsum and zeolites. The chemical composition of the sodium montmorillonite influences the functional properties of the bentonite in significant ways. The type and concentration of various accessory minerals also influence the acceptability of the bentonite in each market.

Jan 1, 1995

By J. J. Snodgrass

Faults, sandstone channels, and abandoned mine workings present severe safety hazards, disrupt mining, and necessitate costly precautions or discontinuance of operations. In addition to fault detection, mining companies have a need to map discontinuities such as seam thinning and previously mined areas in both longwall and room-and-pillar operations. Initial field tests demonstrated successful generation and propagation of higher order guided wave modes. Theoretical studies indicate potential for improved resolution by sensing small details in the coal seam and roof structure. Controlled-waveform source transducers and specialized detectors are particularly useful to preferentially excite and detect the Love (SH) and Rayleigh-type (P-SV) waves, including the higher frequency modes. The distinct observation of reflections using the transducers in the shear wave mode makes feasible the detection of the water-filled voids.

Jan 4, 1985

By SHANTAE LEE, ELAHEH TALEBI, Frank A. Drews, W. Pratt Rogers

Fatigue in mining operations is a serious issue and a significant contributor to incidents and accidents. While mine operators are using or introducing new technology to monitor operator fatigue, there is little work that focuses on the subjective experience of fatigue and the use of fatigue monitoring technology. To investigate this issue, eight focus groups with a total of 44 operators of heavy haulage equipment working for two mining companies in the Mountain West of the USA participated in 1-h focus groups. The topic of the focus groups was the experience of operator fatigue and issues surrounding fatigue at the workplace. The results of the content analyses suggest that operators are well aware of the signs of fatigue, and that they understand the severity of these signs as well. In addition, they are aware of the effect of fatigue on driving performance and are using a wide range of methods to manage fatigue. Finally, based on participants’ assessment, current fatigue monitoring systems lack face validity and reliability and are perceived as not being effective. The results of this study emphasize the importance of a socio-technical systems perspective in the context of miner health and safety management. Only such a comprehensive perspective can result in improvements that are sustainable.

Jun 17, 2020

By P. D. Rao

The combination of high moisture and low heating value has restricted most low-rank coal (LRC) usage worldwide to mine-mouth power generation. Coals from Usibelli Coal Mine and the Beluga coal field have a heating value of approximately 8,000 Btu/lb and 28% moisture. Hydrothermal treatment (at 275 to 352'C) of lump coal from Usibelli Coal Mine and Beluga coal field enhanced the heating value of the coal, on an equilibrium moisture basis, from 8,000 Btu/lb to nearly 12,000 Btu/lb. The product coal with high heating value and 0.2 % S is an environmentally acceptable premium fuel. The Hardgrove grindability index of the coal is greatly improved, further enhancing its value. Increase in hydrothermal drying temperature promotes vesiculation of resinite. Vitrinite reflectance increased to 0.72 and vitrinite was subjected to widespread visiculation resulting in a coke like structure indicative that the material went through the fluid stage.

Jan 1, 1991

By I. Douni

The aim of this study is to synthesize hydrated compounds of calcium silicate (tobermorite) using as siliceous source perlite milling process wastes, containing more than 70% of SiO2. Calcium silicate hydrates are mainly used for construction of lightweight building materials, plasters, tiles and filters. The effect of temperature, time and particle size of perlite on the quality and composition of the solid product was studied. The solid products were characterized by X-ray Diffractometry, Differential Thermal Analysis and the amount of Acid Insoluble Residue. The synthesis of tobermorite was per-formed by the hydrothermal treatment of perlite waste with a saturated calcium hydroxide solution at a molar ratio CaO/SiO2 of 1, liquid to solid ratio 10 mL/g and 1% w.t. NaOH addition. Three experimental sets were performed. In the first series of experiments the synthesis temperature was kept constant at 205°C while the synthesis time varied from 0.5 h to 24 h. In the second experimental series the synthesis time was kept constant at 2 h while the temperature varied between 150°C and 245°C. In the third experimental set the temperature was 205°C and the reaction time was 2 hours and two perlite waste size fractions were used, a coarse (d50=18 µm) and a fine grained one (d50=8 µm). Reaction products consisted of semicrystalline calcium silicate hydrate (I) and crystalline Al-substituted tobermorite or a mixture of both. An isomorphic Si4+ ions substitution with Al3+ ions in the hydrated calcium silicate lattice was detected by thermal analysis. The experimental results show that good quality crystalline Al-tobermorite can be produced after 6 hours of autoclaving at 205°C or after 2 hours of hydro-thermal treatment at 225°C. Generally, the in-crease of synthesis temperature or time favors the crystallization of calcium silicate phases and enriches them in aluminum. The use of fine grain size perlite is more efficient for the hydrothermal synthesis of calcium silicate hydrates.

Jan 1, 2006

By W. J. Schitt

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

Jan 1, 2008

Spirals have become one of the most popular methods for treating fine coal. Unfortunately, spirals tend to produce an undesirably high specific gravity cut-point and often misplace significant amounts of coal and/or rock. In the present study, a process-engineering tool known as linear circuit analysis was used to identify problems with traditional spiral circuits and to suggest alternative configurations. These analyses indicate that a modified rougher-cleaner circuit incorporating a middlings recycle stream offers the best option for improving performance while maintaining a reasonable circulating load. In light of this finding, a full-scale test circuit was installed and evaluated at an existing preparation plant. Data obtained from the plant tests indicate that the new spiral circuit can simultaneously reduce cut-point and improve separation efficiency. Preliminary economic analyses show that the new circuit provides an attractive payback on the capital investment.

Jan 1, 1998

More than 1,200 professionals from the global tunneling and underground space industries are expected to be on hand for the 2009 Rapid Excavation and Tunneling Conference to be held at Caesars Palace in Las Vegas, NV. The conference, set for June 14-17, is sponsored by the Society for Mining, Metallurgy, & Exploration, Inc. (SME) and the Construction Institute of the American Society of Civil Engineers. The four-day conference will feature more than 100 technical papers in 19 sessions. Two one-day short courses are also planned, as are a pair of field trips. And the show?s exhibit will feature more than 120 of the industry?s leading equipment and service suppliers.

Jan 1, 2009

By R. Heiser, J. Vendetti, B. P. Connor, E. J. Haas

Health and safety indicators help mine sites predict the likelihood of an event, advance initiatives to control risks, and track progress. Although useful to encourage individuals within the mining companies to work together to identify such indicators, executing risk assessments comes with challenges. Specifically, varying or inaccurate perceptions of risk, in addition to trust and buy-in of a risk management system, contribute to inconsistent levels of participation in risk programs. This paper focuses on one trona mine’s experience in the development and implementation of a field-level risk assessment program to help its organization understand and manage risk to an acceptable level. Through a transformational process of ongoing leadership development, support and communication, Solvay Green River fostered a culture grounded in risk assessment, safety interactions and hazard correction. The application of consistent risk assessment tools was critical to create a participatory workforce that not only talks about safety but actively identifies factors that contribute to hazards and potential incidents. In this paper, reflecting on the mine’s previous process of risk-assessment implementation provides examples of likely barriers that sites may encounter when trying to document and manage risks, as well as a variety of mini case examples that showcase how the organization worked through these barriers to facilitate the identification of leading indicators to ultimately reduce incidents.

Jan 1, 2018