Search Documents

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

A study was conducted to examine the potential of diesel emissions control strategies based on retrofitting existing power packages with exhaust aftertreatment devices and repowering with advanced power packages. The retrofit systems, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), were evaluated individually using a US EPA tier 2 (ter 2) engine operated under four steady-state conditions and one transient cycle. The DOC effectively curtailed emissions of CO, and to some extent organic carbon (OC), elemental carbon (EC), and aerosol number concentration. The DPF system offered substantially higher reductions in OC and EC mass and aerosol number concentrations. Both, the DOC and DPF achieved reductions in the aforementioned emissions without adversely affecting emissions of NO2 and nano-sized aerosols. The strategy of repowering with an advanced system was examined using a US EPA tier 4 final (tier 4f) engine equipped with a cooled exhaust gas recirculation system and diesel exhaust fluid-based selective catalytic reduction system, but not with a DPF system. The tier 4f engine contributed substantially less than the tier 2 engine to the EC and OC mass, aerosol number, and CO, NO, and NO2 concentrations. The tier 4f engine was very effective in reducing aerosol mass, NO, and NO2 concentrations, but it was not equally effective in reducing aerosol number concentrations. The implementation of viable exhaust after treatment systems and advanced diesel power packages could be instrumental to the underground mining industry to secure a clean, economical, and dependable source of power for mobile equipment.

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

A study was conducted to examine the potential of diesel emissions control strategies based on retrofitting existing power packages with exhaust aftertreatment devices and repowering with advanced power packages. The retrofit systems, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), were evaluated individually using a US EPA tier 2 (ter 2) engine operated under four steady-state conditions and one transient cycle. The DOC effectively curtailed emissions of CO, and to some extent organic carbon (OC), elemental carbon (EC), and aerosol number concentration. The DPF system offered substantially higher reductions in OC and EC mass and aerosol number concentrations. Both, the DOC and DPF achieved reductions in the aforementioned emissions without adversely affecting emissions of NO2 and nano-sized aerosols. The strategy of repowering with an advanced system was examined using a US EPA tier 4 final (tier 4f) engine equipped with a cooled exhaust gas recirculation system and diesel exhaust fluid-based selective catalytic reduction system, but not with a DPF system. The tier 4f engine contributed substantially less than the tier 2 engine to the EC and OC mass, aerosol number, and CO, NO, and NO2 concentrations. The tier 4f engine was very effective in reducing aerosol mass, NO, and NO2 concentrations, but it was not equally effective in reducing aerosol number concentrations. The implementation of viable exhaust after treatment systems and advanced diesel power packages could be instrumental to the underground mining industry to secure a clean, economical, and dependable source of power for mobile equipment.

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

Reducing the contribution of heavy- and light-duty diesel-powered equipment to concentrations of aerosols and gases is essential to industry’s efforts to improve air quality in underground mining operations. The results of this study demonstrated a potential of control strategies based on retrofitting existing power packages with diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) systems and repowering existing systems with advanced power packages to reduce contributions of diesel-powered vehicles to concentrations of diesel aerosols and criteria gases in underground mines. The implementation of viable exhaust aftertreatment systems and advanced diesel power packages could be instrumental in the underground mining industry securing a clean, economical and dependable source of power for mobile equipment.

Reduce permanent hearing losses to bulldozer operators. Approach Two types of noise control packages have been developed, that can be readily fabricated and installed into bulldozers by mine personnel. How It Works Both of the noise control packages reduce the noise exposure of the operator by two techniques, blocking the noise paths or absorbing the sound before it reaches the operator. Both airborne noise paths and noise paths through the machine are blocked. One noise control package is designed for bulldozers having ROPS (Roll Over Protection System), but no cab. The other package is designed for bulldozers having ROPS

Jan 1, 1981

By Takefumi Takuma, Masashi Nagano, Christopher DellAringa

Multiple agencies in Southern California are retrofitting and upgrading their levees to catch up with ever-advancing urbanization affecting the requirements for existing channels and levees in this seismically active zone. Pressed-in sheet piles have been specified on some of these projects to minimize noise and vibration problems associated with sheet pile installation. This paper will study three Southern California levee and sewer pipeline retrofit projects that utilized pressed-in sheet piles in hard soil conditions with N-values higher than 50. BACKGROUND Southern California is home to numerous drainage channels fortified with earthen levees. In spite of the region’s semi-arid climate with varying annual precipitation from year to year, winter storms can bring in heavy and continuous rainfall to the area which overwhelms the levees’ capacities at times. Some levees are running through densely populated areas with homes and other sensitive structures such as underground utilities and bridge piers. Conventional sheet pile driving utilizes either percussive or vibratory pile driving methods, both of which generate high levels of noise and vibration, causing nuisance and potential damage to nearby structures. On the other hand, the press-in piling method utilizes a hydraulic force to push piles into the ground, thus practically eliminating the noise and vibration issue. Although there are types of press-in piling systems mounted on tall leaders on large crawler-base machines, they are less frequently used due to its much larger size and more limited drivability than the type discussed hereunder. The other type of press-in machine sits on top of already installed piles and is anchored with its own weight and additional counter weight when starting off as shown in Figure 1. Once the first few piles are pressed in, the equipment grips on top of the installed piles and moves forward on its own as the pile installation progresses. See Figure 2. This method does not use a vibratory or percussive force to install piles.

Jan 1, 2018

By N. Torres, G. Melcher

"An alternative to building new copper smelters, because of either stringent environmental regulations or in order to expand current plant capacity, could be achieved through the retrofitting of old reverberatory furnaces by making use of tonnage oxygen. The CONTOP® technology offers unique advantages over other techniques for this purpose, especially regarding substantial reduction in bath, capital and operating costs. This is possible to achieve since the reverb throughput could be largely increased with no major structural modifications to the furnace.The following options are offered to the smelter operators: dirty concentrates can be treated in an adjacent Contop system, or the cyclones can be mounted on the reverb roof for either dual operation or full Contop operation. ln the tatter case the furnace will be used as a settling chamber and f or slag c1eaning by top blowing with reducing gases.By incorporating Contop technology, the furnace throughput can be increased, higher malle grade, fixation of sulphur from furnace off-gas and substantial savings in energy consumption are possible to attain.IntroductionCopper smelting has been revolutionized during the last quarter century to such an extent that the standard type of plants consisting o f roasters and reverb furnaces seem a thing of the past, or almost. Though the building of new, more energy efficient smelters is a very likely opportunity for a grassroots plant, it would be hardly justifiable to replace an old existing plant unless there are heavy environmental or economic constraints(1,2,3)."

Jan 1, 1984

By William G. Pariseau

Solvay Chemicals Company mines trona in south-central Wyoming and has done so for many years. The mine is one of several in a mid-continent sedimentary basin that hosts the largest trona resource in the world. Trona is an evaporite, a sesquicarbonate that occurs in several seams of varying thicknesses and depths. Trona is processed into soda ash which has a number of industrial uses in the manufacture of glass, detergent, paper and chemicals. Figure 1 shows the location of the Solvay Mine. A ventilation shaft was recently excavated at Solvay Chemical Company’s mine in the trona patch. In fact, a 22 ft (6.7 m) diameter shaft (inside diameter) was bored upwards from the 1500 ft (457 m) level to the surface. The first bored section was 26 ft (7.9 m) in diameter that allowed for a 2 ft (0.6 m) thick concrete liner. This section began at a depth of approximately 1500 ft (457 m). A second bored section was 24 ft, (7.3 m) in diameter that allowed for a 1 ft (0.3 m) thick concrete liner. This section began at a depth of approximately 750 ft (229 m). This shaft is the #5 Shaft. Figure 2 shows the cutter head used to excavate the shaft.

Feb 1, 2025

The purpose of this paper is to present validation studies of the mine-fire simulator using data gathered from an actual mine fire which occurred in November 1991 at the Pattiki Mine. To develop the model of the ventilation system with the fire in this validation study, the following adjustments were made: (1) flow and gas distribution in the entire ventilation network, and (2) fire parameters matching the data recorded by the monitoring system. After close correlations between simulation and real data were achieved, additional analysis of the ventilation system with the mine fire was performed. Presented and discussed in this paper are the following stages of the fire at the Pattiki Mine: (1) early fire (before the fire was detected), (2) preparation for and fire fighting with water, (3) fire sealing, and (4) fire extinguishing. This study evaluates the suitability of the computer software package for modeling underground fires. The paper also discusses the importance of the on-line monitoring system for the validation process.

Jan 1, 1995

By W. G. Pariseau

A study of coal pillar strength was done at the Beehive Mine during a three year period, 1974?1977, in a cooperative effort involving the University of Utah, RE/SPEC, Inc., and the American Coal Company (Pariseau et al, 1977). The Beehive Mine is located in the Wasatch Plateau coal field in central Utah near Orangeville, Utah, where mines are developed from outcrops between steep canyon walls with topographic relief of a kilometer or so (3,600 ft). Coal is found in Cretaceous sediments that dip gently to the west. Detailed geology of the Wasatch Plateau is described by Doelling (1972). Mining was done in the Blind Canyon seam. An earlier Deseret Mine worked the Hiawatha seam that is lower in the stratigraphic column by about 36 m (120 ft). Mining progress and ownership changes occurred in time with mine mergers and name changes eventually to the collective Des-Bee-Dove label. At the Beehive Mine, depth varied with topography but was approximately 360 m (1200 ft) on average; seam thickness varied from 1.5 to 6 m (5 to 20 ft) and usually required two passes of the miner. The mine was eventually closed and finally reclaimed in 2003. Semborski and Oakley (2006) present a brief history of the mine and describe the reclamation work in some detail. Figure 1 shows the surface topography in the vicinity of the mine that is in the center of the figure.

Feb 23, 2014

By W. G. Pariseau

A study of coal pillar strength at the Beehive Mine in central Utah was done in the 1970s. This study was a cooperative effort by the University of Utah, RE/SPEC, Inc., and the American Coal Company and was funded by the U.S. Bureau of Mines. Mine measurements of closure at 117 points and pillar stress using 119 vibrating wire stress gauges were made during retreat mining in this room-and-pillar operation. Laboratory testing for the strength and modulus of 372 coal cylinders up 0.3 m (1 ft) in diameter and 0.6 m (2 ft) in length was also done. Two-dimensional finite element model analyses complemented the study. However, the real world of mining is three-dimensional and in consideration of the significant advances in computing power since the time of the original study, a revisit of the data seemed warranted. In this regard, a novel finite element method was used that allows for the whole-mine analysis of tabular excavations on the kilometer scale and yet enables details to be obtained at pillar walls on the meter scale. The effects of material properties variability in situ and of joints can also be taken into account. Results that compare computed two- and three-dimensional seam-level closures with mine measurements show noticeable differences; three-dimensional results are reasonable, while two-dimensional results overestimate closure by nearly a factor of two.

Jan 1, 2014

By Letz H

An investigation of earthquake hazard in Papua New Guinea (PNG) by a yearly extreme magnitude method using the magnitude 7 earthquake record since 1900 shows that the Bougain-ville Island seismic zone is by far the most active, followed by the New Britain and northern mainland PNG regions. Return period for magnitude 7.0 earthquakes occurring in normalized 10,000km2 areas of the Bougainville Island, New Britain, Huon, West Bismarck, North Sepik and Ramu seismic zones is 37, 60, 81, 88, 125 and 125 years respectively. These areas are much more active than the California Seismic Zone 4 region including the San Andreas Fault, which has a normalized magnitude 7.0 return period of 299 years, calcul-ated here by the same method.Only southern PNG, including the Papuan Fold Belt and most of the Bismarck Sea, are less active than California Zone 4. The Papuan Fold Belt is only marginally less active than California Zone 4, but more active than the State of California taken as a whole.

Jan 1, 1994

By C Dell

Hillgrove, situated on the New England plateau of New South Wales, is an area rich in history and resources. Key resources are predominantly antimony, gold and scheelite and the area surrounding the historical field is environmentally sensitive and topographically challenging. Since acquiring the Hillgrove leases, Straits Hillgrove Gold has undertaken a significant exploration program on these historical mining areas with the goal to return the field to production. This exploration program has enabled Straits to significantly increase the resource base and has subsequently enabled the planned redevelopment of Hillgrove to be realised. In October 2006, installation of mining infrastructure and the initial stripping of existing development had commenced. To successfully redevelop Hillgrove, Straits has had to adopt a highly mechanised, trackless, diesel mining operation which will see the production rate commence at an initial rate of 250 kt/a of ore from a narrow vein environment. This ore will be processed on site to produce antimony metal, gold bullion and a scheelite concentrate.

Jan 1, 2008

Thirty years ago a party of American Engineers, with members of their families, belonging to the four national engineering societies, sailed for Europe and visited England and the Paris Exposition of 1889 and received many courtesies, official, professional, and individual. Plans: have been made for a reunion dinner to be held in New York City, about May 26, at which it is hoped that all survivors, ladies as well as men, of that trip may meet again. It is, therefore, urgently requested that anyone who was of that party communicate immediately with the Secretary of the Committee, Jesse M. Smith, Engineers' Club, 32 West 40th St., New York, N. Y. Announcement of the precise date and place, and full details, will he sent to every individual who can he reached.

Jan 5, 1919

By Wolfgang Baum

Remediation work on thermal process dusts and slags has been primarily based on chemical analyses. These data offer little information for the assessment of treatability and reuse potential. In addition, the lack of mineralogical residue characterization has frequently caused time-consuming and inefficient waste management. This paper will outline the cost-effective, and sucessful use of process-oriented mineralogical analyses for treatment and beneficial reuse of various thermal residues. These include a patented process for detoxification of Pb-contaminated bottom ash, the pyrometallurgical treatment of K 061, the reprocessing of lead smelter slag as well as various power plant residues.

Jan 1, 1992

By Asok Kumar Das

"In steel making ferroalloys occupies a commanding role for production of varied quality of steel. Ferroalloys enable alloying elements such as chromium, silicon, manganese, vanadium etc to be safely and economically introduced into metallurgical processes thus giving certain desirable properties of the alloyed metal. Their importance grew with the progress of the steel metallurgy which implied more diversified alloying elements, in better controlled quantities, in purer steel. The ferroalloy industry became a key supplier to the steel industry. Production of ferroalloys generally involves the use of Electric Arc furnace(EAF) into which raw materials(e.g. various metal ores, quartz, coke, lime etc ) with relatively fluctuating physical compositions are loaded. Due to this, one of the major environmental impacts of producing ferroalloys is the emission of dust and fume from the smelting process. INTRODUCTIONFerro Alloys are essential ingredients used for refining, de-oxidation, desulphurization and alloying addition in the production of different types of steel and hence Ferro Alloy industry forms a back bone of iron and steel in the world. Indian ferro alloy industry is more than 45 years old. It produces most of the bulk ferro alloys and a large number of special ferro alloys. The present installed capacity of the Indian ferro alloy industry is sufficient to meet the requirement of existing level of indigenous steel production of about 46 million tonnes. Revised National Steel Policy – 2008 envisages production of more than 100 million tonnes of steel by the year 2011-12, at proportionate annual growth rate per annum. The focus of the policy is to achieve global competitiveness not only in terms of cost, quality and product-mix but also in terms of global benchmarks of efficiency and productivity. In order to achieve the objectives of National Steel Policy and also to meet the requirement of ferro alloys, the Indian Ferro Alloy Industry has to gear up in terms of enhancement in production capacity, sourcing of raw materials, up gradation of technology, improvement in productivity, automation / mechanization, customer satisfaction etc."

Jan 1, 2008

By C. M. F. Vieira

In the county of Campos dos Goytacazes, north of the State of Rio de Janeiro, Brazil, there is a large production of red ceramic, mainly perforated bricks. A percentage of these bricks are damaged during the firing processing and become a red ceramic waste. This work investigates a possible solution to this environmental problem through the mixture of fired brick wastes, up to 20 wt.%, with clay bodies to produce red ceramics. Cylindrical pressed bodies were fired at temperatures varying from 500 to 1100ºC. After firing, samples were then tested for linear shrinkage, water absorption and mechanical strength. The results showed that brick waste addition did not changed the workability of the clay and that up to 5 wt.% of waste no detrimental effect occurred on the fired properties at all temperatures.

Jan 1, 2010

By Paloma Camargos, Saulo De Rezende

In the pursuit of sustainable development, the mining industry is constantly evolving, recognizing the importance of utilizing all extracted materials. Nexa addresses waste management in the mining industry, with an emphasis on the adoption of waste as innovative and sustainable raw materials. With a focus on exploring the potential of mining waste, the characteristics of materials from the Vazante and Ambrosia units were evaluated to determine their suitability as aggregates in the construction industry, as well as to identify other possible applications.

Sep 29, 2023

By B. Nebreda, I. Vegas, R. Vigil, O. Rodríguez, M. I. Sánchez de Rojas, M. Frías, R. García, J. Urreta

"This paper shows the possibility of reutilize paper sludge waste as supplementary cementing material for the cement manufacture. This industrial waste consists essentially of a mixture of organic matter (30%) and inorganic compound, such as calcite and clay minerals. The raw paper sludge does not present pozzolanic properties, but once calcined at 650ºC during 2 hours, exhibits high pozzolanic activity, similar to silica fume at 28 days, as a consequence of the transformation of kaolinite into metakaolinite. Calcined paper sludge was used as partial Portland cement replacements of 0, 5, 10 and 20%. Enhancement in compressive strength was appreciably obtained for 10 and 20% substitution levels from 7 days on. Furthermore, calcined paper sludge slightly reduces the initial and final setting times of cement paste. Introduction Natural pozzolanic materials have been ordinary used in different aspects of construction, mainly for their influence on the microstructure and durability of blended cement matrixes [1, 2]. Due to the regulations of environmental protection, many researches are focusing on the possibility of obtaining pozzolanic materials from industrial wastes and not from natural materials (ceramic wastes, silica fume (SF), activated clays) [3–5]. One of the most used pozzolanic products is the metakaolin (MK) obtained from the activation of natural clay (kaolinite). The positive effect that MK has on blended cement performances [6,7] and also the influence that curing temperature and matrix nature have on the reaction kinetics and stability of hydrated phases produced during the pozzolanic reaction, according to the studies carried out by Frías et al. [8,9] are well known. However, there is a worldwide trend towards the use of recycled products in cement industry. In this line, some authors have reported an alternative way of obtaining MK from waste paper sludge [10-14]. The raw paper sludge (PS), once calcined under controlled conditions (700-800ºC), produces a MK with pozzolanic properties [15-20]. The present research is part of an experimental study about alternative source for MK from the Spanish paper recycling industry and its use as supplementary cementing material. This contribution pays special attention to the option of reducing activation temperature below 700ºC. This fact has a positive effect in reducing the energy consumption, as well as in reducing environmental impacts associated with decarbonation of calcite. The chemical and mineralogical characteristics of raw paper sludge and derived calcined product are described. In addition, the influence and behavior on blended cement properties (setting times and mechanical properties) are also discussed."

Jan 1, 2008

By Carlos Guillen Morales

Como parte del proyecto de estudio de impacto ambiental presentado por la Compañía Minera Antamina (Ancash), el presente trabajo describe la reutilización de las aguas residuales de los procesos mineros realizado en Huarmey. El estudio plantea el transporte el concentrado de mineral desde la mina hasta el puerto de embarque en Huarmey a través de camiones utilizando una carretera que facilitaría el desplazamiento de los mismos. Una vez llegado el concentrado al puerto de embarque, se separaría el agua del concentrado y el agua sería tratada para luego descargarla en el mar. Sin embargo, por análisis posteriores, se optó por otra propuesta más ecológica, donde se traslade los concentrados de cobre y zinc en suspensión acuosa a través de un minero ducto, y el agua tratada remanente del transporte de mineral, sería disipada mediante una plantación forestal, evitando la descarga al mar, generando empleo y una extensa área verde en el desierto de Huarmey. De forma que se innova en la minería a través de la reutilización de las aguas y se desafia las condiciones extremas del desierto costero para desarrollar una superficie vegetal que consumiera esta agua.

Sep 12, 2005

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010