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By K. Hajmrle

The production of nickel coated mica composite powder by hydrogen reduction of a nickel ammine sulphate solution, followed by the production of molded plastic samples containing Ni/Mica is described. Sample preparation by injection or compression molding is outlined and the better results in compression molding are explained by the combination of better particle-to-particle contact, less particle breakage during processing, and more random particle distribution in the plastic. Three volume resistivity measurement techniques are described and compared. Two of them (conductive paint and silver-rubber electrodes) are found reliable and are used throughout the work. The influence of nickel content and particle size of Ni/Mica on volume resistivity is evaluated and the optimum product defined. One of the most important assets of Ni/Mica, its ease of injection molding, is demonstrated by the good electrical properties obtained with little optimization of the injection molding process. Surface roughness of molded plastics with and without Ni/Mica is briefly discussed. Shielding effectiveness of Ni/Mica in four plastics (PP, ABS, PBT and PC) is presented and correlated to volume resistivity data for the same materials. The addition of 15 to 50 weight % Ni/Mica (3 to 16 volume %) to plastics and subsequent injection or compression molding produces composite materials having low volume resistivities (0.03 to 1 ohm.cm) and high shielding effectiveness (40 to 70 dB).

Jan 1, 1988

By Adrian J. Mathias

For many years excavations were made in rock exclusively by conventional blasting methods, and without concern for damage to the rock surfaces which remained after the excavation was completed. Recently, however, there is an increasing awareness for the importance of making rock excavations with as little damage as possible to the remaining rock surfaces; consequently, several revolutionary new precision blasting techniques have been developed during the past few years. These techniques, variously known as cushion, smooth- wall, perimeter, pre-shear, and pre-split blasting, basically involve the creation of a fracture plane in the rock between a series of blasted holes. The variations in each of these techniques are largely due to the differences in hole diameters, hole spacings, methods of charging, and sequence of blasting used to achieve certain specific results. The development of these precision blasting techniques was initiated by Canadian Industries Limited in 1953 at the time the Sir Adam Beck No. 2 Hydro-electric Project was under construction by the Hydro-Electric Power Commission of Ontario. Since then, these techniques have been somewhat advanced, and they have been applied with varying degrees of success to a number of projects. These projects include railroad and high- way cuts, dam spillway channel excavations, canal excavations, tunnel driving, shaft sinking, and other underground applications.

Jan 1, 1965

By Joe Rigney, Conrad Stacey, David Nowak, Chris Blanchard, Michael Beyer, John Czach

Originally constructed in the 1930s, the 1-mile-long Sumner Tunnel is 31 feet in diameter and carries traffic deep below Boston Harbor, connecting Boston and East Boston. This project includes both design and construction for the rehabilitation of the nearly 100-year-old tunnel. The primary work includes repairing advanced deterioration at the tunnel crown with new precast arches that will add protection and strengthening. The restoration also consists of upgrading the tunnel systems, including permanently removing 75% of the existing exhaust duct suspended over the roadway to improve the overall ventilation system capacity and performance.

Jun 23, 2024

By Albert J. Kritscher

The Similkameen Copper Project located near Princeton, British Columbia, is operated by the Similkameen Mining Company Limited, a wholly-owned subsidiary of Newmont Mining Company. The orebodies for this project are located on both sides of the Similkameen River for which the project is named. The project involves the processing of an average of 15,000 STPD of andesitic ore, mineralized largely with Chalcopyrite, at an overall plant availability rating of 90 percent. Project life is nominally 15 years. Design for the plant and its ancillary facilities was undertaken by Bechtel Corporation with procurement and construction management by Canadian Bechtel Limited. Construction began in June 1970 and first ore was introduced into process in March 1972. This paper concerns itself only with the project tailing system. The processing plant is located on a bench of glacial stream gravels which overlooks the river canyon. This site represented the only relatively flat area of sufficient size to accomodate processing facilities near to the ore- bodies. Reference is made to Figs. 1 and 2 showing the relationship of project features in plan and profile.

Jan 1, 1973

By Gill Montgomery

Although fluorspar is considered an industrial mineral by usage and value, its geological occurrence and the mining and milling methods employed make it more akin to the non-ferrous metal ores. Likewise methods of exploration for it are more like those used in the search for lead and zinc, with which fluorspar is often mixed. In fact, it often takes the mixture of fluorspar, lead, zinc, plus maybe barite to add up to enough recoverable values to make the mineral an ore by definition. This is so true where the fluorspar portion is low grade, perhaps less than 25 percent. Until the development of modern steel milling in World War I times, the invention of aluminum smelting, and development of the fluorine chemical industry and air conditioning, there were few uses for fluorspar aside from ceramic fluxes in the flint glass industry and for uses as glazes for pottery and china. Pure fluorite crystals have long been admired as semi-precious and ornamental minerals of many delicate colors.

Jan 1, 1983

By Ray E. Harris

New developments have occurred in Wyoming's industrial minerals industry since the 32nd Forum on the Geology of Industrial Minerals in Laramie, Wyoming in 1996. The soda ash trona and bentonite industries have experienced overall growth. Gypsum and limestone production have remained constant, but have the potential for dramatic growth. The mining of zeolite ceased in 1997. The struggling dimension stone industry has increased production, but development has lagged behind the schedule predicted in 1996. The construction of a container glass plant and associated production of glass raw materials, as predicted in 1996 and imminent in 1998, is now on hold due to unforeseen market factors. Increases in railroad and highway construction have, and will, greatly increase the production of construction aggregate for local uses. An iron carbide industry, not foreseen in 1996, is in the planning stages.

Jan 1, 2001

By Robert L. Major

The expanded role which coal has been assigned in the energy future of the United States has raised numerous policy questions. The very complexity of these questions makes them suitable to analysis by econometric models. However, as the Wall Street Journal indicated in its recent article, business' success with such models have been mixed. I have been asked to present my views as to how coal producers can use such models and in what ways the industry is likely to be impacted by such models. I do not presume to speak for the whole coal industry, but only to share with you the personal observations of one who has worked "both sides of the street", having been employed' both by government and a consulting firm prior to joining the coal industry. In my opinion, the use of econometric models to analyze the coal industry will impact the coal producers in two main ways. First, their use by government will have a profound impact on future government policies related to the mining, transportation and utilization of coal. Second, such models, when properly calibrated and refined, may become useful tools for the coal producers in doing market research and long-range planning. While the former has already begun to impact on the operating environment or the coal industry, the latter is still in the embryo stage.

Jan 1, 1977

By John Relser

The production processes that are developed in the mining and minerals industry are manufactured to be exposed to very aggressive environments. Chemical, abrasion, and impact expose structures and equipment, steel or concrete, to a significant deterioration. This causes damage and adds high costs to operations that can be reflected in the destruction of equipment and structures in the arrest of the production process, which becomes very costly. Also, there is the potential for personnel accidents, which would require large sums of compensation for an employee, thus directly harming the image of the mining operation and company. Manufacturers of paints and coatings that have major centers for research and development (R&D Labs) distributed globally have developed high-tech products for durable protection from the elements for structures and equipment used in the mining industry. The difference between these paintings and coatings and what is normally known as conventional paints (e.g., those called domestic or decorative), is its chemical composition, structured around polymeric components that have highly resistant, chemical and physical properties to cope with extreme conditions to which they are exposed. With this, and only this, longer life of components can be achieved for equipment and structures used in the production processes of the mining industry. Today, in addition to the important features mentioned, some manufacturers of the paints and coatings dedicated to this highly modernized process have invested large sums of money in developing new products that add operational elements to the painting process. These coatings provide added value and significant performance to companies mining operations and that we can describe in three fundamental concepts:

Feb 1, 2014

By Joaquin Ruiz

Although Mexico is known for its important base-and precious-metal deposits, and lately oil, some industrial minerals play an important role in the Mexican economy. Sulfur, the most important industrial mineral produced, accounts for approximately 7.5 percent of the total value of mineral production. This commodity is followed by fluorspar, which accounts for 6.4 percent. Predominantly, the fluorspar deposits are very high grade (75 percent CaF) and are contained in lower Cretaceous limestone in the states of Coahuila and San Luis Potosi. Base-metal deposits in the area of Parral (notably San Francisco del Oro), however, have become important fluorite producers in their own right. (San Francisco del Oro has 12 percent fluorite gangue.) Salt from the Guerrero Negro solar-evaporation ponds in Baja California account for 6 percent of the total shares; phosphate from Baja California also accounts for 6 percent. Barite from man to deposits in Lower Cretaceous limestone in Coahuila and exhalative deposits in the Paleozoic section of Sonora account for 1.0 percent. In addition, Mexico is an important producer of gypsum, graphite, and celestite. Although graphite and celestite are not large-scale operations and thus do not contribute much to the Mexican economy, the Mexican graphite and celestite deposits are among the most important in the world; Mexico is one of the world's few sources of celestite. The celestite is in the form of large, high-grade mantos in Cretaceous limestones in northern Mexico.

Jan 1, 1987

"A commercially available Through-the-Earth (TTE) communications system was evaluated at an active underground longwall mine in West Virginia. This TTE system uses electric field (E-field) sensing to send text based communications using two separate antenna arrays connected in parallel. Each antenna array is composed of interconnected, grounded metallic rods or other such structures. Two-way communication between subsurface locations was investigated in this study using various antenna configurations. This field study was conducted as a part of a larger multi-site evaluation of available TTE systems in an effort to determine their operational sensitivity. INTRODUCTION Wireless, Through-the-Earth (TTE) communication technology is designed to achieve point to point communication through solid strata using very low frequency (VLF) and ultra-low frequency (ULF) electromagnetic waves. This ability allows TTE communication to function without the need for intermediary communications infrastructure, such as repeaters. As a result, such communication systems have the potential to provide reliable, robust communications between surface and underground personnel. Exploration into the use of TTE technology for this purpose dates back to the 1920s (Jakosky and Zellers 1924; Pittman, Church and McLendon 1985), but U.S. permissibility requirements slowed the development of TTE equipment for widespread implementation (Durkin 1980; Pittman, Church and McLendon 1985). One of the primary challenges in producing wireless TTE communications is the counteraction of signal attenuation when propagating through solid strata (Barkand, Damiano and Shumaker 2006; Wadley 1949). The long wavelengths of TTE transmissions make them well-suited for reducing the rate of attenuation. However, even when operating within the VLF to ULF range, the performance of TTE systems is still affected by geologic and anthropogenic factors (Geyer 1973; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Jakosky and Zellers 1924; Large, Ball and Farstad 1973). Although commercially developed TTE systems have demonstrated the ability to communicate through a variety of conditions, their range and performance have been highly varied (Barkand, Damiano and Shumaker 2006; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Ilsley, Freeman and Zellers 1928; Jakosky and Zellers 1924; Yenchek et al. 2012)."

Jan 1, 2016

By Joseph H. Herz

Recently, the President of the Portland Cement Association, Robert D. Maclean, gave the keynote address at the Rock Products Eighth International Cement Industry Seminar. He said, after listing the seven plagues our industry is suffering, "none of these items I have listed is a sales or marketing problem. Further, none is a problem that can be relegated to long-term study by public or private research agencies. They are here-and-now problems to be faced daily by producers, researchers, equipment manufacturers and consultants. THE DAY OF THE PRODUCTION MAN IS HERE." (1)

Jan 1, 1973

By Yerkezhan Madenova, Kairat Kalmurzayev

This study intends to demonstrate the engineering application of ground penetrating radar (GPR) that would enable site engineers to prevent the high cost of blind drilling. At the tailing dump located in Zhairem Mining and Processing Plant, the challenge of sheet pile driving is encountered due to the indefinite watertight clay layer deposition depth that serves as a protective layer against groundwater contamination. A numerical model of the soil underlying the tailing dump is built using the existing hole data to compare and confirm the existing geological cross sections for three profile lines along the south and southeast parts of the tailing dump. GPR is employed to investigate the subsoil geological structure and detect the watertight clay layer deposition. On the basis of radargrams tied to the existing borehole data in the numerical model, 21 drill hole locations are suggested to assess and confirm the clay layer depth along profile lines at the tailing dump. The drilling results of the suggested holes confirmed the expected depth of the clay layer. It is concluded that GPR is a practical and economic subsurface mapping method that can prevent the high cost of blind digging of the ground and orient the drilling operations effectively.

Jan 12, 2023

By Victor J. Scaravilli

This report is based on experience developed on the construction of one contract for the Buffalo, New York subway. The Buffalo subway is under construction for the Niagara Frontier Transportation Authority and is called the LRRT-Light Rail Rapid Transit or more commonly the Metro. The Initial Route of the Buffalo subway construction started early in 1979 and is scheduled for completion in May, 1984. The initial system includes 5.2 miles of underground construction, 1.3 miles at grade for a total of 6.5 miles of subway system. A total of fourteen stations, eight underground and six at grade are included on the system. The Initial Route has a planned expansion to 17.3 miles in the future. On January 15, 1979, a Joint Venture of S & M Constructors, Inc., Solon, Ohio, James McHugh Construction Co., Chicago, Illinois, and Kenny Construction Company, Wheeling, Illinois, was awarded contract 100031, the Line Tunnels from Amherst Street to South Campus in northcentral Buffalo between Delaware Park and the State University, (see Fig. 1, Location Plan) This $35,000,000.00 contract was designed by Hatch Associates Consultants, Inc., Buffalo, N.Y. The Notice to Proceed was issued January 15, 1979 and the scheduled completion date is August 18, 1981. The project consists of two parallel rock tunnels with a minimum excavated diam of 18 ft 0 in. and a final concrete lining of 16 ft 0 in. diam. The tunnels total 14,630 linear ft. In addition to the tunnels, contract C-31 includes four shafts, an underground pump station, three cross passage connections, and other minor work items. (see Fig. 2, C-31 Project Plan and Profile) The tunnels were constructed primarily within the Bertie Formation, an approximately 50 foot thick moderately fractured to massive, dolo-

Jan 1, 1981

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 J. J. Antony

The Cactus Gold Mine is a joint venture comprised of Middle Buttes Partners Ltd. (CoCa Mines, Inc.--operator, T. Congdon and W. Carey) and Compass Mining, Inc. The project includes 2.4 sq. miles of contiguous mining claims and leases in the Mojave Mining District, Kern County, California, approximately B5 miles northeast of Los Angeles. The property is readily accessible year round by all-weather roads and is within 6 miles of the main line of the Southern Pacific Railway.

Jan 1, 1988

By Anand Kumar, Debasis Deb, A. K. Mishra, M V. N. S. PRASAD.

In the Adriyala project, shield-leg pressure data from all shields and shearer location with time stamp from a mechanized longwall face are monitored and recorded in a surface computer. The data contain random noise due to power failure, leakage of legs, bad sensor readings, and other maintenance or geomechanical problems. An algorithm has been developed to detect mining cycle parameters such as setting and final pressures and duration of the cycle from these data for the analysis of periodic roof weighting phenomena. The intensities and persistence of periodic roof weighting are vital information for mine management to make judicious decisions on longwall operation.

By C. Heckman, M. S. Moats, A. Luyima, W. Cui

"Chloride ions and their interactions with two organic smoothing additives – Cyquest® N-900 and HydroStar® 4208 – during copper electrodeposition were explored using cyclic voltammetry and electrochemical impedance spectroscopy. The results revealed that chloride ions, up to a concentration of 40 mg/L, depolarized the copper deposition reaction. A combination of chloride ions and Cyquest N-900 inhibited the depolarization reaction during copper electrodeposition. It is proposed that the chloride ions acted as bridging ligands between copper and Cyquest N-900. Addition of HydroStar at a concentration of 2.5 mg/L depolarized the copper deposition reaction when no chloride ions were present. This behavior did not change with the addition of chloride ions at the concentrations tested, indicating that chloride ions and the polysaccharide do not interact.IntroductionElectrowinning is a major production method used to obtain high-purity copper. In modern tankhouses, copper is electrodeposited onto stainless steel blanks and then stripped, washed and bundled for delivery. Significant improvements in the quality of electrowon copper have been made over the last few decades. Additives, temperature, current density, electrolyte concentrations and agitation are known to influence the quality of copper electrodeposits (Jenkins and Eamon, 1990).The influence of chloride and organic additives on copper electrodeposition has been the subject of considerable research. The addition of small quantities of chloride and organic additives has been recognized to significantly improve the properties of copper electrodeposits. These additives are critical in the prevention of dendrite growth and the production of smooth, dense cathode deposits.Chloride ions have been reported to catalyze the copper reduction reaction and assist in the production of uniform deposits (Lakshmanan et al., 1977; Sun and O’Keefe, 1992). Moreover, it is generally agreed that chloride ions depolarize the copper deposition process at low (several millimolar) chloride concentrations. This is because chloride ions catalyze the reduction of copper (II) ions to copper (I) ions (Cu2+ ? Cu+ + e-) in the rate-limiting step of this process (O’Keefe and Hurst, 1978; Ilgar and O’Keefe, 1997; Hebert, 2005; Shao, Pattanaik and Zangari, 2007)."

Jan 1, 2016

By Brett P. Spigarelli

"To meet the growing need for CO2 capture and storage technology, Michigan Technological University is studying CO2 capture using alkali-based solvents. The objective of the present study was to find a way to increase the absorption rate of CO2 into an alkali solution without reducing the absorption capacity of the solution. One approach to increasing absorption rate is to use a surfactant to chemically alter the gas bubble size. The surfactant chosen for the study was a neutral-charge polypropylene glycol methyl ether (PPGME) with a molecular weight of 200. Experiments were conducted to study the absorption rate of CO2 at varying surfactant concentrations. Results showed that as the concentration of PPGME increased in solution, the absorption rate also increased. The CO2 absorption rate increased from 3.45 x 10-3 mol/min CO2 at 0g/L PPGME to 3.92 x 10-3 mol/min CO2 at 0.48 g/L PPGME. This amounted to a 14% increase in the CO2 absorption rate with no decrease in the absorption capacity of the solution. IntroductionChemical absorption using an amine solvent is currently the most mature carbon capture and storage technology available. Amines are advantageous in that they have a fast CO2 absorption rate, which leads to a high CO2 removal efficiency. However, amine absorption has some considerable drawbacks, such as high energy requirements, high equipment corrosion rates, amine degradation in the presence of oxygen, high waste generation and a large increase in plant footprint if new equipment is constructed (Herzog and Golomb, 2004; D’Alessandro et al., 2010). Due to these drawbacks, Michigan Technological University (MTU) is studying CO2 absorption using alkali-based solvents, which address the above disadvantages of amine solvents."

Jan 1, 2015

By William Gleason

During the past five years, mining operations have had access to press technology for piping and joint fittings that can save owners a significant amount of time when installing or replacing pipes by eliminating the need for welding or threading. Viega, with North American headquarters in Wichita, KA, entered the mining sector in 2009, adding to its already expanding industrial sector. Since then, the company?s global engineering department has paid considerable attention to its industrial division, bringing its expertise in plumbing solutions for residential and commercial buildings to the mining and mineral extraction industry. ?We have a lot of applications in the mining industry.?We have a lot of applications in the mining industry throughout the United States, Canada and Mexico and continue to expand in the mining industry,? Tom Shields, Viega?s director for industrial accounts explained. ?Since we made the decision to increase our presence in the industrial markets, we have been aggressive and more than 240 applications have been approved by our engineering department in Germany.? Getting approval from Viega?s engineering department is no small feat. During a tour of the manufacturing facilities in Ennest and Großheringen, Germany, Mining Engineering, as well as a select few other publications and clients, were shown Viega?s manufacturing process. At the Ennest facility, hundreds of millions of fittings are produced, and each one is inspected mechanically and with a laser at the end of the production line. With four production facilities in Germany and one in the United States, Viega is able to ship to anywhere in the world. The company distributes everything from fittings to stainless steel pipe.

By Faruk Oksuz, Dave Schiemann, Miguel Sanchez, Patrick Jensen

"The McCook Main Tunnel connects Chicago’s Tunnel and Reservoir Plan (TARP) Mainstream Tunnel to the McCook Reservoir. The tunnel system consists of a 10 m (33 ft) finished diameter and 490-m (1,600-ft) long hard-rock tunnel constructed from a 27.5-m (90-ft) diameter and 92 m (300 ft) deep main gate shaft. The gate shaft houses six high-head 4.4 x 9 m (14.5 x 29.5 ft) wheel gates installed in the bifurcated and steel-lined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir. Construction of the McCook Main Tunnel in live flow conditions was a challenging task for the McCook Main Tunnel Project participants, the project owner U.S. Army Corps of Engineers (USACE), local sponsor Metropolitan Water Reclamation District (MWRD) of Greater Chicago, designer Black & Veatch and contractor Kiewit Infrastructure Co. (Kiewit). Once completed in two stages in 2017 and 2029, the McCook Reservoir will hold 38 billion L (10 billion gal) of combined sewer overflows (CSO) and flood waters from the city of Chicago and 36 surrounding communities in Cook County, IL The construction of the tunnel system was divided into two contracts. The first contract for the gate and construction access shaft was completed in August 2011. The second contract included tunnel excavation and concrete and steel lining that was completed in September 2014; installation of gates and hydraulic cylinders that was completed in June 2017; and the last major construction activity was the removal of a temporary concrete plug (bulkhead) and lining that tunnel section to bring the overall tunnel and gates system online before Dec. 31, 2017.This article focuses on the installation, testing and commissioning of the high head wheel gates. Live tunnel connection details to TARP Mainstream Tunnel were addressed in a previous paper submitted at the World Tunneling Conference in 2016."

Mar 1, 2019