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By K. J. Shoop, S. J. Ripke, T. C. Rao, T. C. Eisele

This study investigated the use of a 7.6-cm inside diameter, 344.2-cm-tall horizontally baffled column to reduce the ash content of a low-sulfur bituminous coal. Tests were carried out to determine how the baffled column responded to changes in feed rate, reagent dosage and feed quality. The tests were also carried out to compare the columns performance to a conventional column installation in an operating plant. In this paper, the results of this investigation are reviewed and discussed.

Jan 1, 1999

By D. Duvris

Health and safety issues are a very important aspect of mining activities. Although the application of scientific research and current technology shields workers from many dangerous aspects of mining, accidents do happen. Many companies and institutions worldwide have committed to a continuous effort to minimize such occurrences. In this study, the health and safety data pertaining to the Greek mining and quarrying industry for the last 3 decades are presented and critically evaluated with respect to number of workers, annual production, etc. Appropriate indices are also calculated regarding the incidence and frequency of accidents. Health and safety issues specific to mining in Greek are also discussed.

Jan 1, 2000

By Diómedes Sarmiento

Centromin is a Mining Company owned by the peruvian government. It's considered as one of the major mining and metallurgical center in Latin America. The main operations of the Company are: Mining, Concentration, Smelting and Refining of several metals (Figure 1). At present, dentromin operates with six mining units: Cerro de Pasco, Morococha, Casapalca, San Cristobal, Yauricocha and Cobriza; which are located in the Central part of the country between 2 100 m and up to 4 800 m above sea level. The installed capacity of concentration all together ranges about 14 000 tons per day. There's also a metallurgical plant in La Oroya with a production capacity of 220 000 tons per year of refined metal. The production of the Company is diversified in twenty two (22) final pro- ducts, whose major productions are : copper, lead, zinc, silver, gold, tungg ten and bismuth. The minor products are: arsenic, antimony, cadmiun, teluriun, sulphuric acid, indium, selenium, etc.

Jan 1, 1979

By David A. Smith

A new generation of reliable, stable, and easy to use bulk emulsions allowing application in tunneling and drift rounds has been developed. This new product group of bulk emulsions has been especially formulated for use in small-diameter holes and is a significant advancement in bulk emulsion technology. Reliable and easy-to-use bulk delivery equipment has been designed and developed to allow bulk emulsions to be used in a wide variety of shaft and tunneling applications.

Jan 1, 1987

By A. K. Bakshi

An on-line rheometer, suitable for use with slurries, has been developed at Michigan Technological University. This rheometer can be used with both Newtonian and non-Newtonian slurries, and produces complete shear-rate/shear stress curves which characterize the time-independent rheology of the slurry. The sensor utilizes the Hagen-Poiseuille equation and Boyle's Law to calculate the shear rate, slurry flowrate, and shear stress from a series of pressure measurements. The design of the unit allows the measurement sample to be continuously collected from operating process streams in the often-hostile on-line environment. The shear rate/shear stress curves can be used to conveniently calculate the apparent viscosity at any given shear rate, and also to measure any yield stress or other deviations from Newtonian behavior.

Jan 1, 1999

By F. B. Henderson

1.0 PROLOG Since the "end" of the Cold War, revolutionary new research and commercial remote sensing capabilities are being developed that will dramatically change the way we map the earth and address its environmental problems. The technology challenge is not the growth of new environmental remote sensing technologies themselves. It is, rather, how these new innovative observing systems can be accepted and used to the benefit of both the regulatory and the mining communities in the light of present concerns about unknown risks of discovery and liability. The basis for this paper is an unpublished technology primer prepared for the industry-government Workshop on Advanced Measurement and Site Characterization for Mining Impacts held at Colorado School of Mines, Golden, Colorado, July 14-17, 1997

Jan 1, 1999

By R. W. Smith, D. L. Taylor, K. A. Altman

Recent research has shown that traditional sensitivity, what if and best case/worst case analysis of metallurgical data has the potential to over estimate the value of mining projects. Use of simulations, which rely on the input of statistical information, may provide more realistic predictions of the value of future projects. Actual metallurgical data is used to demonstrate that analyzing the data from a statistical perspective can give insight into completing an optimum amount of metallurgical testing and a mechanism to determine that samples used for the testing are truly representative of the ore that will be processed.

Jan 1, 2000

By Charles K. Presley

This paper deals with drilling large diameter shafts for the mining and construction industry with diameters in excess of 3 feet to more than 20 feet in diameter. It discusses appropriate applications of the rotary drill method, linings for large diameter shafts, circulation systems,, and the limitations of the method. Each specific rotary drill method is determined by the geology of the area, the depth to be drilled and the formation fluids encountered. Shaft lining or casing must be improved to result in lighter weight, higher strength and lower cost. All phases of rotary drilling equipment must be improved to drill shafts in excess of 10 feet in diameter. As these goals are reached, more shafts of large diameter will be drilled by the rotary method for the mining and construction industry.

Jan 1, 1967

By S. K. Kawatra

Under normal conditions, a significant amount of pyrite is recovered in the froth during flotation of high-sulfur coal. In order to reduce this pyrite recovery, it is first necessary to determine the primary recovery mechanism, as different measures are required for reducing entrainment, locked-particle flotation, or true hydrophobic flotation. In this paper, evidence is presented which suggests that hydrophobic flotation is not the major mechanism for recovery of liberated pyrite, and that the bulk of the recovered pyrite is there either as a result of simple entrainment or by being physically locked with floatable coal particles.

Jan 1, 1991

By G. Barelli, C. Giusti, W. H. Langer

Natural aggregate – sand, gravel, and crushed stone – is the number one non-energy mineral resource in the world in terms of both volume and value. A plan for the sustainable development of aggregate resources can include: 1) policies and economic incentives to encourage identification and protection of potential resources, 2)efficient quarrying and processing of aggregate, 3) efficient use of primary aggregates, 4) greater use of recycled, waste, or substitute material, 5) inclusion of costs of all environmental impacts in price of material, 6) reclamation to beneficial secondary uses, and 7)identification of objectives, targets, actions, and sustainability indicators. Quarrying can also contribute to sustainable ecosystems through natural habitat reclamation.

Jan 1, 2003

By F. N. Siddiquie, Mohd Shaif, Rajiullah Khan, Juned Alam

Manganese ore bodies of Banswara Mn belt were classified into stratiform and stratabound types, based on their mode of occurrence, distribution, and their chemical characters. These ore bodies generally composed of braunite, pyrolusite, cryptomelane/ psilomelane, wad, etc. The stratiform-type Mn ore bodies are conformable with the associated host rocks (Mn phyllite, etc.) and occurred in the form of layers, bands, etc., which are variable in their shape and size. These ore bodies are also strongly folded with the enclosing host rocks. The others, which are stratabound-type Mn ore bodies, also showed an intimate association with the associated host rocks. These types of ore bodies occurred in thin layers, pockets, lenses, stringers, etc. The classified ore bodies are confined with Kalinjara formation of Aravalli Supergroup of Paleoproterozoic age. The ore bodies are structurally controlled and well associated with phyllite, schist, limestone, quartzite, etc. The stratiform-type ore bodies constitute a marginal to low Mn grade and are also characterized by lower Mn content (26.19–39.24%) along with the Mn/Fe ratio of 7.16–12.23, while the stratabound-type Mn ore bodies are rich in Mn (35.92–49.64%) along with the higher Mn/Fe ratio of 14.15–23.97. However, the poor Mn grade along with high siliceous impurities of Banswara Mn deposits is subjected to them for intermittent mining activities in the past and, consequently, did not attract the scientific and industrial community for the evaluation of these resources. Therefore, the authors attempted this study in a scientific and systematic manner (mode of occurrence/distribution and possible methods for evaluation/exploration) to evaluate the potential of existed and newer Mn deposit resources in the Banswara Mn belt. The whole findings would be very much helpful for exploration/ mining geologist along with other concerned, to completely evaluate these Mn deposits in the future.

Aug 16, 2021

By John B. Mitchell

Approximately 90% of all potash produced is employed as a fertilizer, either directly or with nitrogen and phosphorus. The remaining 10% is utilized in the manufacture of other chemical products, The original source of potassium was wood ash (hence the name potash), However, today the term potash refers to all commercially important salts of potassium. Sylvite, usually found associated with halite, is the predominant economic potash mineral; carnallite a lesser important source of potassium chloride, while langbeinite is important as a source of potassium sulphate. The world's first potash mining operation commenced in Strassfurt, Germany about 1860, Since that time the industry has grown steadily to its present annual volume of about 30, 000, 000 tons of potassium chloride products or 18, 000, 000 tons of K2O equivalent, potassium chloride or "muriate of potash" being equivalent to 63. 1% pure K2O, WORLD POTASH RESERVES ARE NOT EVENLY DISTRIBUTED The earth's crust contains 2 to 3 per cent potassium, mostly in the form of insoluble silicate minerals. The economically important deposits, however, are formed from brines concentrated by evaporation. The world's most important commercial deposits are of Devonian and Permian age, however soluble potassium bearing salts are presently being concentrated by evaporation in several drainage basins, notably Searles Lake, California, Great Salt Lake, Utah' and in the Dead Sea. At least twenty-four countries are known to have reserves of potash: Canada and the USSR have over 80% of the presently known world reserves, (Figure 1)

Jan 1, 1972

By Keith Whitworth

The USSR, over the last 20 years, has continued to increase its out-put year by year and it is now almost four times what it was at the end of the Second World War. In 1975, it exceeded 700 million tons of run-oi-mine coal (all ranks) which amounts to over 20 percent of world output. This rapid progress has been due to modernization of the industry, by means of increased mechanization and automation and the development of new machines and systems for underground workings and by the expansion of open-pit workings and the development and implementation of larger earthmoving machines.

Jan 1, 1977

By Trevor R. Ellis

The extractive industries addition to the International Valuation Standards (IVS) is scheduled for publication in the next edition of the IVS book in January 2005. This will provide guidance for valuation of minerals and petroleum industry assets of all types for all appraisal uses. It will provide asset valuation support to the International Financial Reporting Standards for the stock markets of the world, and a global umbrella standard which can be supplemented for local needs by institutes and regulators. This paper discusses implementation of the IVS within the minerals industry and important issues that the industry should confront.

Jan 1, 2005

By G. Delagrammatikas, M. Karmis, J. Mastoris

The evaluation of raw materials in terms of quality profile, mineralogical character and mechanical properties is of great importance to the cement industry. The variability of their chemistry and structure is among the decisive design parameters in the choice of any mining, handling and preblending systems. Furthermore, clinker and cement production require sound estimates of the above parameters, to help produce some appropriate and realistic raw mix configurations and achieve minimum standard deviation of the major components. This paper addresses this subject from the perspective of a cement producer and presents the principles of a methodology aimed at optimizing mine planning and process design. Finally, results from case studies on actual sedimentary deposits currently in operation are discussed.

Jan 1, 2002

By Ian Farmer, Nigel Glossop, Philip Garritty

Performance of tunnel boring machines - usually expressed in terms of penetration per revolution - is determined by relations between machine thrust and torque, head diameter and rock strength. It can be shown that for a given machine power and head diameter there is only one rock strength at which the machine performs optimally. In weaker rocks the available torque limits performance and in stronger rocks, the available thrust. Performance data shows that, historically, machines have been designed to cut weaker rocks. Optimization of thrust is required to improve performance in stronger rocks.

Jan 1, 1987

By A. Suarez, M. Menendez, M. R. Gent, P. Riesgo

"Recent requirements to reduce thermal coal plant emissions, and ultrafine coal's tendency to produce these emissions due to its typically high ash and moisture contents have limited the use of ultrafine coal. Ultrafine coal in beneficiation plants are usually either disposed of in tailing ponds at a loss in combustible material or disposed of by blending with coarser higher-grade products, resulting in a reduction in marketed product quality. A study of the options for processing ultrafine coal, consisting of < 200 µm hydrocyclone overflow, with 38.8 percent ash content is presented here. Ultrafine coal was processed based on 200-µm sieve bend and 10-µm hydrocyclone classifications, enhanced gravity separation (EGS) and froth flotation concentration as well as combinations of these. Yield, combustible material recovery (CMR) and product humidity were evaluated as test results.Depending on the processing applied, product ash content could be reduced up to 49.7 percent, and up to 95.8 percent CMR of the actual run of mill feed could be attained. All of the processing options analyzed could reduce produced thermal electric plant emissions due to ash and moisture from 22 to 38 percent of the actual unprocessed ultrafine coal product.Froth flotation was found to be the optimal process, yielding a product with the lowest ash content attained of 19.5 percent and CMR of 92.3 percent. Being the most versatile of the processes evaluated, it is capable of producing coal with varied ash contents but is subject to potential variations in coal flotability. The most complicated of the processing options, a combined sieve bend recovery of the > 200 µm fraction and EGS processing of the 10 to 200 µm fraction was found to be the next best option, attaining a combined 90.1 percent CMR and 25.0 percent ash content. IntroductionMunicipal, regional and national objectives to reduce fossil fuel combustion emissions and their effects on air quality and global weather changes are affecting thermal electric plant operations. Plans and regulations such as President Obama's Clean Power Plan (U.S. Environmental Protection Agency, 2015), the European Directive 2010/75/EU (European Commission, 2010) and China’s proposed Enhanced Actions on Climate Change (Wei, 2015) are of major significance to thermal electric plant operations. Although thermal plant efficiencies depend in large part on the losses of heat by plant components, the ash and humidity contents of thermal coal invariably reduce plant efficiencies and increase emissions of carbon dioxide (CO2), nitrogen oxides (NOx) and dust.Any noncombustible material present in thermal coal will result in higher CO2 emissions per unit of energy produced. Since no particle emission control can be totally effective, it is to be anticipated that any reduction in coal ash content will also result in reduced particle emissions. Kurose, Ikeda and Makino (2001) reported that NOx emissions also increase with coal ash content. The effect of coal moisture content during combustion is complex. Kurose, Ikeda and Makino (2001) showed that an increase in coal moisture content significantly reduces thermal NOx to total NOx production, and Bosoaga et al. (2006) showed that it tends to reduce NOx emissions. Since the humidity, pyrite and ash content of thermal coals directly affect thermal electric plant efficiencies and emissions, minimizing these factors should facilitate, at least in part, compliance with thermal electric plant emission limits. This, in turn, would affect the specifications and prices of the coal preparation plant products."

Jan 1, 2016

By S. K. Singh, J. Shepherd

"Feather edging"- a major source of injury and fatal accidents in Australia, South Africa and USA, refers to a phenomenon where the roof, at the goaf edge, falls as a thin wafer of rock often suddenly, over-riding conventional timber breakerlines. It may run down and affect adversely a working bord at distances of 15 metres or more from the goaf edge. Feather edging typically occurs in relatively massive, strong roof strata such as sandstone or conglomerate. This paper presents the results of a mine trial where a concentrated row of fully grouted bolts were able to resist the feather edging in the first comprehensive, monitored trial in an Australian pillar (&apos;total&apos;) extraction coal mine.

Jan 1, 1999

By Lei Fu

In the wake of the collapse of the ceiling panels in the I-90 section of the Central Artery/Tunnel (CA/T) Project in 2006, the long term performance of tunnels became the focus of the tunneling industry. At the time of the accident, the tunnel had been open to traffic for about 10 years. This paper will discuss design methods and considerations to improve the long term performance and durability of a tunnel. The major problems found during the inspection of several tunnels will also be presented and the causes for these problems will be discussed.

Jan 1, 2008

By Jerry Williams

GEORGE WEINMAN: At this time, our co-chair, Jamie Davis from Phelps Dodge, will come to the podium. JAMIE DAVIS: Our next speaker is Jerry Williams from Phelps Dodge, Morenci. Jerry is the maintenance planning supervisor and is in charge of preventative maintenance and maintenance scheduling. Jerry&apos;s group uses predictive tools to monitor and predict the equipment failure throughout the mine, from pumps to shovels to motors, you name it. The title of Jerry&apos;s talk is "If You&apos;re Not Using Predictive Tools, You&apos;re Behind the Curve." I’ll turn it over to Jerry.

Jan 1, 1998