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By Tony Peglas, Harry Asche, Eva Wood

The North-South Bypass Tunnel is a new $AUD1.5 billion underground traffic route in Queensland, Australia, a project of the Brisbane City Council. The tunnel is approximately 5.2 km long, bypassing the Central Business District, and is adjacent to and below major buildings and services. Road tunnel alignment issues include the complex southern connections to the Pacific Motorway and the design of ramps to the east and the north. A review of road tunnel alignment criteria and accident data for Australian and overseas tunnels, similar to the proposed NSBT, are discussed. The key findings of this review lead to a rationalization of the traditional tunnel cross sectional width allocation. The road alignment design elements adopted for the NSBT are also discussed. The NSBT route crosses beneath the Brisbane River. Geotechnical investigations and hydrogeological modelling are described. The crossing has a fundamental impact on the alignment and the tunnelling methods. The tunnelling methods to be adopted and the tunnel support are described. The geotechnical investigations and hydrogeology analysis culminate in the selection of a single shielded TBM for the reference design. These outcomes are related to complex issues of hydrogeology and contaminated groundwater. These are discussed in detail.

Jan 1, 2005

By Takashi Sakaguchi, Akira Nakajima

Some attempts were made to recover and remove heavy metal elements, such as uranium, copper and chromium, from aqueous systems by using several phosphate compounds. The phosphorylated derivatives of polysaccharides, chitin phosphate, chitosan phosphate and cellulose phosphate, have high abilities to accumulate heavy metals, such as uranium, copper, manganese, cobalt, cadmium, zinc, nickel and chromium, compared with non-phosphorylated polysaccharides. In order to obtain basic information on the recovery and removal of uranium that may be present in industrial effluents, mine waste water and seawater, the adsorption of uranium by chitin phosphate and chitosan phosphate was investigated in details. The adsorption of uranium by chitin phosphate and chitosan phosphate was much greater than copper, cadmium, manganese, zinc, cobalt, nickel, magnesium and calcium. The adsorption of uranium was very rapid and was affected by pH of the solution, temperature. granule radius and co-existence of carbonate ion. The amounts of uranium adsorbed on the adsorbents increased linearly as the external uranium concentration increased. Uranium adsorbed on chitin phosphate easily desorbed with diluted sodium carbonate solution. On the other hand, uranyl and cobalt ions were separated from each other by using chitin phosphate. Along with these fundamental research, some attempts were made to recover uranium from seawater.

Jan 1, 1993

By Tad S. Golosinski, R. Larry Grayson

Online education is not new. During the last decade, it has reached the stage where many universities offer a variety of courses, degrees and programs without any associated residency requirements. The most successful of the online universities, University of Phoenix, offers hundreds of accredited programs for close to 100,000 students throughout the world (www.phoenix.edu). Online education is considered to be a valid equivalent to traditional, classroom-based education. It is best suited to the needs of mature students with full-time jobs and a desire to deepen their knowledge. While most of the e-business has experienced severe setbacks during the last two years, e-education shows no signs of slowing down. On the contrary, the number of students and institutions offering online education keeps growing. The value of e-education associated expenditures was expected to reach $300 billion in 2001 (Sanoff,2001), making it a serious and mature industry.

Jan 1, 2002

During development mining, ventilation capacity may decrease and the ventilation requirements may depart from initially planned values depending on the mining rate, increases in the methane emission rate, and changes in ventilation airway leakages. Insufficient ventilation air quantities and the occurrences of high methane liberation rates can overwhelm the existing quantity of ventilation air and result in elevated levels of methane gas during development mining. This condition can both limit the development of that section and increase the risk for an ignition that may lead to an explosion. Thus, the prediction of ventilation air requirements prior to mining can enhance worker safety by reducing the likelihood that explosive methane-air mixtures form. This study presents an approach for prediction of methane inflow rates using coalbed methane reservoir modeling. For this purpose, a two-phase coalbed reservoir model of a three-entry type roadway is developed. In the model, grids are dynamically controlled to simulate development of entries. Examples are given for methane inflow and ventilation air requirements as a function of mining rate, development section length, mining height, and the existence of degasification boreholes. This technology can be used to limit the methane concentrations occurring as a result of the influences of various coalbed and operational parameters.

Jan 1, 2008

By C. K. Lee

The influence of passageway fires on ventilation flows was investigated in three horizontal fire tunnel s: 1. a laboratory-scale fire tunnel network, 2. a small-scale fire-plume tunnel, and 3. a large- scale simulated mine gallery. Wood was used in the first and third tunnel and gas-burners were used in the second one to generate passageway fires. Experimental measurements included gas mass flow rate, velocity, temperature and pressure in the passageways and exhaust fans. The overall and local effects of the fires were investigated by comparing these measurements obtained before and during the fires. Results show that a passageway fire essentially increases the flow resistances of the passageways of a tunnel flow network by virtue of volatile fuel mass injection and high combustion temperatures. The ventilation air flow rate is consequently throttled to lower values than that before the fire. At severe throttling, reverse flow occurs. Conditions for reverse flow are characterized by two Froude numbers based on gas velocity and density upstream of the fire, and height of the passageway. The Froude numbers and the characteristics of the passageway fire are necessary to analyze mine ventilation/fire interaction and to predict mine ventilation patterns during fires.

Jan 1, 1980

By M. Abdelkhalek, M. Hepworth, D. Tao, B. K. Parekh

Pre-combustion coal cleaning and post-combustion flue gas desulfurization (FGD) using lime or limestone are the primary methods employed to reduce sulfur dioxide (SO2) emission from coal combustion. These processes generate voluminous pyrite and gypsum solid wastes that are usually landfilled, occupying thousands of acres of land and creating serious land and water pollution problems due to the release of acids and toxic substances. An integrated process has been developed for the combined utilization of gypsum and pyrite wastes by converting them into useful products including lime, sulfur, and direct reduced iron (DRI). The process includes four major steps. The first step is to concentrate pyrite from coal preparation tailings using flotation or gravity separation. The second is the thermal decomposition of pyrite into pyrrhotite and sulfur. This is followed by the reduction of pyrrhotite with carbon in the presence of lime to produce iron and calcium sulfide. The fourth step involves the reaction of calcium sulfide with gypsum to produce lime. The chemical reactions involved in the process were studied using thermogravimetric analysis (TGA) and X-ray diffraction (XRD)techniques. Process variables studied included reaction temperature, time, reactant composition, and purity of reactants.

Jan 1, 2000

By William R. Yernberg

The combined 75th Annual Minnesota Section of SME meeting and 63rd Annual University of Minnesota Mining Symposium was held April 9 and 10, 2002, in Duluth, MN. This year’s theme was “Keys to the Future: Imagination, Innovation and Technology.” The meeting consisted of plenary and technical sessions and a special General Manager’s Session. The technical paper presentations included concurrent mining and mineral processing sessions. In the General Manager’s Session, representatives from the region’s taconite operations presented the current status, concerns and future plans for each of their operations.

Jan 1, 2002

By T. W. Beck

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dusts escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dust hog-type bit to improve dust extraction during the critical initial phase of drilling. A twisted-body drill bit is also evaluated to determine the quantity of dust liberated by comparison to the dust hog-type bit. Based on these laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emissions can also be substantially reduced. The use of a twisted-body bit has minimal improvement on dust capture compared to the commonly used dust hog-type bit.

Feb 27, 2013

By Lothar Baumann, Wilhelm Knickmeyer

In mechanized roadheading predominantly two methods of rock breakage are applied at present: the cutting method by means of picks and the cutting/crushing method by means of roller cutters. Both systems meanwhile reached a high degree of technical development and consequently show very few possibilities of further improvement. While application of hard-metal picks is limited by rock hardness, the roller cutters require a high specific thrust, and, accordingly, heavy carrier systems. Roller-cutter equipped tunneling machines are therefore only cost-effective in hard-coal mining if the high investments for transport and assembly are justified by a corresponding length of road to be headed. The limit for acceptable cost-effectiveness is at present a minimum heading length of approximately 3 km. In order to improve the specific cutting performance of roller cutters by activation, Bergbau-Forschung carried out a research project sponsored by the Commission of the European Communities and the provincial government of

Jan 1, 1981

By H. Sis, S. Chander

The beneficial effect of a series nonylphenol polyethylene glycol ether surfactants were tested in the flotation of phosphate ores in which the mixture of sodium oleate and dodecane was used as collector. The performance of nonionic surfactants was first tested in the microflotation of pure apatite mineral. Microflotation experiments showed that the recovery of apatite depends on the number of ethoxylation of the nonylphenol surfactants and decreased with higher ethoxylation. The nonionic surfactant with the smallest ethoxylation group used in this research (NP-4) was then tested in batch flotation of phosphate ores. The flotation of three different size phosphate ores was carried out in the absence and presence of NP-4 surfactant. The beneficial effect of nonionic surfactant was obtained for fine size (-35+150 mesh) and very fine size (-150+400 mesh) phosphate ores at different collector dosages studied. But, in the flotation of coarse size (-16+ 35 mesh) phosphate ore the beneficial effect of nonionic surfactant was obtained only at high collector dosages.

Jan 1, 2002

By Victor Bush

Most governments recognize that energy efficiency represents a partial solution to reducing global capital shortages and environmental crises that threaten to seriously impede economic growth. Much of the United States and many foreign countries are embracing the concept of Strategic and Tactical Energy Planning (STEP) which incorporates Supply Side Management (SSM) and Demand Side Management (DSM). Since SSM comes at twice to three times the cost of DSM, it makes economic sense to employ the energy conservation techniques of DSM. This paper will explain these concepts, the effects of the energy industry restructuring, and risk management for the development of an overall strategic and tactical energy plan.

Jan 1, 1999

By Leonard Harris

Mining is a business and, therefore, is expected to make profit for its investors, like any other business. It is a risky business which requires the expertise of professionals from several disciplines to make it successful in the finding, evaluation and development of a new mining venture. Many of the same disciplines, as well as experts in some other fields are required to operate the facilities once they are built. To manage all this, wide-ranging, versatile and sharp managerial skills are required. On the U.S. domestic front, the most important management issues requiring attention today and tomorrow are the increasing unwarranted attacks by anti-mining groups and legislators on the industry and aided by an unchallenged, but widespread, public view that mining is not necessary and damages the environment. Higher costs to mine and process deeper and more refractory ores are also of great concern. More and more attention is being focused, therefore, on overseas projects under the belief that undeveloped countries will recognize the economic value of mineral production and that lower costs can be achieved.

Jan 1, 1993

By G. A. Kosick, L. Kuehn

The design of an information management system (IMS) for a mineral processing plant requires prior consideration of many factors, which can be broadly categorized into two domains, process plant considerations and IMS considerations. The process plant considerations include: plant characteristics, management and personnel issues, existing organizational standards and policies, and the level of existing hardware and software systems. The IMS considerations include: system functionality, system sizing and desired performance, hardware components, software components, and system support issues. All of these aspects must be addressed in order to achieve a functionally successful and cost effective system. The purpose of this paper is to lay out these design issues and, in doing so, to provide process engineers with a guideline with which to tailor a system that is best suited to their specific application. The paper is completed by presenting an approach that has been used in two Canadian concentrators. Both of these plants have incorporated MillEX, a software system designed specifically as the central component of a mineral processing IMS.

Jan 1, 1993

By Elif Emil-Kaya, Bernd Friedrich, Merve Papakci

Samarium (Sm), one of the rare earth elements (REEs), and cobalt (Co) are used in the production of SmCo permanent magnets, which have excellent temperature stability, corrosion resistance and oxidation resistance. Of the two types of SmCo magnets, one contains a high amount of iron, approximately 15.2 percent. This paper focuses on the recycling of iron (Fe)-bearing SmCo. In this study, an oxidative leaching process with nitric acid was developed to eliminate iron through in situ hydrolysis and to dissolve REEs and Co. The influence of experimental conditions on the formation of an amorphous iron compound through the hydrolysis of Fe3+ in a nitric acid environment was thoroughly examined based on a Taguchi orthogonal array. The optimal parameters for oxidative leaching were determined to be an acid concentration of 3 mol/L, a solid-to-liquid ratio of 1/10, and a process temperature of 60 °C.

Jul 1, 2024

By J de Cuyper, E. J. Parkins, H. L. Shergold, W. Freyberger

The paper is divided into two parts. The first part describes an investigation of the effect of temperature on the conditioning and flotation of an ilmenite ore with a 1:l oleic acid-fuel oil mixture as collector. During conditioning the pulp underwent characteristic changes of flocculation, deflocculation and dispersion which were monitored by measuring the power consumption of the conditioner motor. Optimum flotation results were obtained at the end of the deflocculation period. High ilmenite recoveries were obtained at high temperatures and high concentrate grades at low temperatures. The second part of the paper describes a study of the effect of temperature on the adsorption of oleic acid at the ilmenite/water interface. At high adsorption densities it was chemical and exothermic. Contact angles showed that the hydrophobicity of the collector-coated minerals increased with an increase in temperature.

Jan 1, 1976

By A. Venkatachalam

Spinel ferrites, like NiFe2-2x Znx Ti4 O4 Fe CO1.5 Ge0.5 Tix O4, Ga1-x Fex Ni CO O4, Nil-x Fex Mn2 O4 have been prepared using the respective metal oxides in Stoichiometric quantities, by the ceramic method. The oxides were homogenized in acetone medium, pelletifed by using poly vinyl acetate as the binder. They were fired at 1000°C for 100 hours for compound formation. Chalcogenide spinels such as Zn1-x Cux Cr2 Se4 where 0=x=l and Cu1-x Fex Cr2 Se4 where 0=x=0.3 have been prepared by using 99.99% pure elements and then fired at 1000°C in quartz ampoules under vacuum conditions. X-ray diffraction studies of these compounds indicated a single cubic spinel phase. DC resistivity studies of the compounds were taken between 300-700K using LCR bridge by two probe technique. Thermo-electric power measurements were taken between 300-500K for all the compounds. Initial susceptibility studies have been carried out using a low field (0.506) and from which the nature of magnetic dimains and Curie temperatures were determined. Magnetic hysteresis measurements were carried out at 300K and at 80K, using alternating current hysteresis loop tracer, at 2K02 field. Mossbauer spectral measurements were carried out using Co57 source embedded in a copper matrix and an absorber containing 0.3 mg/cm2 of the sample. The spectra has been fitted by Mossfit Program. The catalytic effect of the spinel ferrites NiFe2-2x Znx Tix O4 where 0=x=1 has been studied by using the model reaction of decomposition of H2O2 at temperatures from 40°C to 70°C. It was found that the spinel oxides were found to possess poor catalytic activity.

Jan 1, 1990

By Nikhil C. Trivedi, Robert W. Hagemeyer

Despite the apparently unflattering term filler, this group of industrial materials has become an essential component of many industrial products with varying degrees of sophistication. Mineral fillers are, by definition, inert materials included in a composition for some useful purpose. Included in this broad category are asbestos, barite, bentonite, natural calcium carbonates (limestone), clays, diatomite, feldspar, micas, silica, talc, and other industrial minerals. Also included in this category are synthetic mineral- derived materials such as aluminum hydrate, precipitated calcium carbonate, and pyrogenic and precipitated silicas and silicates. Mineral fillers are included in compounds to accomplish a variety of final results. Inclusion of fillers modifies physical characteristics such as hardness, brittleness, impact strength, compressive strength, surface texture, fire resistance, softening point, and electrical conductivity. Depending upon the performance characteristics of the particular filler used and the quantity of the usage (i.e., percentage added), these materials can enhance the physical and optical properties, price-performance, and appearance of the finished products. These enhancements in properties of the finished compounds are the result of properties of the fillers including chemical activity, purity, hardness, particle size, particle shape, particle size distribution, surface structure, color, density, and refractive index. This chapter will review the general usage of fillers, the rationale for their use, trends, and economic factors influencing those trends. Major using industries will be examined in detail with extensive discussion of major fillers used in those industries. The reader is referred to the appropriate commodity chapter for specific information on deposits and processing for industrial minerals. All of these same filler materials have additional significant uses based on their chemical composition or other characteristics. Cross-references for these will be found in other use chapters and summarized in commodity chapters. The chart in Table 1, updated from the 5th edition of Industrial Minerals and Rocks, illustrates the major mineral fillers (both natural and synthetic) and their more important end uses.

Jan 1, 1994

By Eric M. Hill, Daniel E. Walsh, Hsing K. Lin, John T. Hollow

The Fort Knox Mine is located in Alaska’s interior where the average ambient air temperatures range from -24°C in January to 16°C in July. The mill processes a free milling gold ore utilizing both a gravity recovery circuit and conventional cyanide leach/carbon-in-pulp circuits. Plant slurry temperature cycles seasonally and allows for a unique opportunity to measure the impact temperature has on gold leach kinetics, carbon adsorption efficiency and cyanide destruction reactions. Mathematical models have been developed to accurately predict actual mill performance. This paper describes the development of the models and presents data that allow for a better understanding of the impact of circuit operating temperature on process efficiencies.

Jan 1, 2005

By S. C. Westerfeld

The original patent for the gyratory crusher was granted to Philetus W. Gates in 1881. This first crusher was used by the Buffalo Cement Co. At the time these early gyratory crushers were developed all mining and quarrying, either underground or open pit, was done by hand; tonnages generally were small and product specifications simple and liberal. Likewise plants were small and demands for small product sizes practically nonexistent. In addition to substantial amounts of hand labor, the available material handling equipment was small, simple, and not suited to handling large run of mine ore. Mine can, cable ways, or belt conveyon transporting crushed material to the mill had limited capacity per hour. At the turn of the century the largest Gates crusher, the No. 9, had a receiving opening of 21 x 48 in. with a three-arm spider and a 21 x 80-in. opening with a two-arm spider. The steam shovel began to change the entire picture of open pit quarrying. As a result of the use of steam shovels around 1910 crushers with 48-in. receiving openings were built; thus it can be seen that the basic gyratory crusher was developed prior to World War I. The improvement of the internal combustion engine and the use of pneumatic tires created a new set of operating conditions. Early mines were small, using shrinkage stoping and small mine can. The capacity of material handling was small, limiting the size of the largest piece and the feed rate. Improved material handling resulted in more and more large open pit mines with large shovels and a tremendous increase in the size of off road or mine haul trucks or rail can. Primary gyratory crushers also increased with receiving openings as large as 60 in. and connected hp of 1,000.

Jan 1, 1985

By Robert L. Cheek, Sid McIlveen

Sodium sulfate is an important industrial chemical. As recently as ten years ago it was produced and consumed in the United States in quantities exceeding 1 Mtpy. Since then, both its production and use have declined; however, approximately half the production still comes from natural sources. [Fig. 1] illustrates the history of production of natural sodium sulfate in the United States. Production of natural sodium sulfate from various types of deposits is the main source of this chemical in Canada and Mexico, and probably in Argentina, Chile, Iran, Spain, and the Russian Republics. MINERALOGY AND PHYSICAL PROPERTIES Sodium sulfate is widespread in occurrence and is a common constituent of many mineral waters, as well as seawater. Atmospheric precipitation contains sulfate; it is one of the major dissolved constituents of rain and snow (Davis and Dewiest, 1966). Many of the saline lakes throughout the world contain varying amounts of sodium sulfate. Because sodium is usually the dominant cation, some workers make an anionic distinction, referring to lakes containing predominantly sulfate as bitter lakes and those containing predominantly carbonate as alkali or soda lakes (Bateman, 1950). Sodium sulfate in its natural form is found in two principal minerals, mirabilite and thenardite. Mirabilite, the hydrous form, is commonly called Glauber's salt. It was discovered by the German chemist, J.R. Glauber (1603-1668), who derived its name from the Latin, sal mirabile, meaning wonderful salt. Thenardite, the anhydrous variety, was named for the French chemist, Louis Jacques Thenard (1777-1857) of the University of Paris (Mitchell, 1979). The largest quantities occur in the form of mirabilite. Sodium sulfate is found in varying degrees of purity, from theoretically pure efflorescent crystals of mirabilite to combinations and admixtures of other salts and impurities. It is a common constituent of some brines; from this source much is extracted commercially. Sodium sulfate also is found in compounds, such as the minerals glauberite, the double salt of anhydrous sodium and calcium sulfate, bloedite, the hydrous double-salt of sodium sulfate and magnesium sulfate, and burkeite, the anhydrous double-salt of sodium carbonate and sodium sulfate. Over 40 minerals contain sodium sulfate in varying proportions; many are of special interest because of their frequent occurrence. Table 1 lists some sodium-sulfate bearing minerals. The reader is referred to other publications (Cole, 1926, Dana, 1932, Grabau, 1920, and Dietrich, 1969) for descriptions of these minerals. Only mirabilite and thenardite will be described herein. Mirabilite Na$04.10H20, contains 55.9% water of crystallization. It is noted for its efflorescence or spontaneous loss of water. On dehydration it changes to the anhydrous form, Na2S0,. Mirabilite is an opaque to colorless, water-soluble mineral that tastes first cool, then slightly bitter. It has a specific gravity of 1.48. It frequently forms as efflorescent, needlelike monoclinic crystals, but generally is found in the massive form. Thenardite, the anhydrous mineral, Na2S04, contains 43.68% Na20 and 56.32% SO3. It ranges from colorless to white and may be tinted shades of gray or brown. It is a water soluble mineral with a slightly salty taste. Its specific gravity (2.67) and hardness (2.5 to 3) exceed those of mirabilite. It commonly occurs in the massive form without visible crystals. Its crystals are frequently tabular pyramids of the orthorhombic system. Sodium sulfate also occurs as a heptahydrate, containing seven molecules of water, but this is unstable and has not been found in the natural environment. The solubility of sodium sulfate has an important effect on the crystallization of the salt in nature, as well as in its production. Its solubility in water generally increases as a nonlinear function of temperature. Below 1.2°C, ice and mirabilite form. As the temperature is increased above O°C, increasing amounts of sodium sulfate become soluble. At 32.4°C, a transition point on the solubility curve is reached, as the decahydrate melts in its own water of crystallization and the anhydrous form crystallizes. With in- creasing temperatures, solubility decreases somewhat. The presence of other dissolved salts changes the transition temperature and solubility characteristics of sodium sulfate.

Jan 1, 1994