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Electronic detonators are receiving increasing acceptance in the blasting industry. Electronic detonators offer several distinctive features over electric and non-el (shock tube) detonators including better timing accuracy resulting in excellent fragmentation and vibration control, field programmability and digital safety means. Several electronic detonator systems are available commercially today serving the surface, underground and seismic needs.

Jan 1, 2010

By Michael J. Beus

The National Institute of Occupational Safety and Health-Spokane Research Laboratory (NIOSH-SRL) have developed a Shaft Conveyance Monitoring System (SCMS). Assessment of current hoisting technology has shown that monitoring wire rope tension and conveyance position and load directly from the skip or cage top offers several significant safety, production, and maintenance advantages. The SCMS consists of conveyance position and guide displacement sensors, a battery power supply and charging system, and a new sensor to measure hoist rope tension. This device provides a warning of the occurrence of ?slack rope? a particularly dangerous condition. A 2.4 GHz radio link transmits data to the hoistroom. A reduced scale hoisting test facility has been constructed to test these components prior to field trials. The advantages of monitoring wire rope tension and conveyance position and load directly from a skip or cage top will be discussed. Field tests are underway in full-size shafts to refine the concept and evaluate long-term reliability and maintenance requirements. Application of this technology may result in decreased maintenance costs as well as safer, more productive hoisting operations.

May 1, 2001

By Lyle F. Smith

With the demand for larger diameter raises under all ground conditions and the increasing price of drill rods and operating costs, it was evident that there was a need for a raise borer with a variable-speed drive and fast-response torque limiting control. The raise boring machine described in this paper was developed after several years of market research and discussions with mine operators and construction contractors. This paper discusses the Ingersoll-Rand raise borers with the solid-state controlled DC motor drives. These machines have gained wide acceptance in the five-year period since being placed in operation and are designed to accommodate the range of raise diameters and lengths most required today.

Jan 1, 1978

By Mu Chen, Ye-Shuang Xu, Dong-Wei Hou, Shui-Long Shen, Huai-Na Wu

"This paper presents a laboratory investigation on the mechanical behaviors of the cement-clay admixture improved by polypropylene fiber. Cement can significantly improve the clay admixture. The fiber additive also improves the strength and ductility of the improved clay. The Unconfined Compression Strength (UCS) of the polypropylene fiber-reinforced cement-clay presents an overall trend to grow with the increase of fiber length. The improved clay reached its peak strength at the fiber content of 0.5%. Then the UCS of the improved clay will slowly reverse if the fiber content continues to rise. For study of curing time, improved clay behaves better in its early strength, but an inhibition will be brought about if fibers are excessive.INTRODUCTIONGround improvement technology is essential for construction of structures in soft ground. Some traditional techniques often cost much but result in little. For instance, along the coastal region of China, soft ground is often improved by backfill with high quality sandy soil transported far away, leading to high additional haulage costs and long construction period. Reutilizing the excavated soil as backfill or subgrade after treatment, by contrast, will be more economical and effective (Hufenus et al., 2006). Many researches have been conducted to improve the compression strength of soft soil, among which, the method of mixing the soft soil with cement and fly ash is one of the most common ways (Kolias et al., 2005; Horpibulsuk et al., 2009; Porcino et al., 2012). It is known that soil resists well against compression and shear force but behaves poorly in resistance to tension. Therefore, utilizing tensile elements such as fibers and strips to improve the tensile strength will be effective because of its strength isotropy, better durability and cost effective (Haeri et al., 2000; Kaniraj and Havanagi, 2001; Consoli et al., 2010)."

Jan 1, 2015

Slurry technology developed for the marine transport of mineral commodities has been increasingly applied to on-shore slurry transport systems. Reclaim of mineral concentrates, sand tailings for mine backfill and various industrial minerals from storage tanks or ponds normally require a slurry of high density at constant flow rates to improve process performance and to reduce handling costs. An efficient system must accomplish this at minimum capital costs with maximum reliability. Continuing improvements in equipment design to improve repulping efficiency and their application are discussed.

Jan 1, 1986

By Charles G. Crans, Naresh Gurpersaud

"Toronto’s Union Station, a National Historic Site occupying an entire city block, is the busiest commuter rail transportation hub in Canada. An extensive project is being undertaken to revitalize Union Station while maintaining the historical significance of the building and minimizing disruption to commuters. A significant stage of the revitalization involves excavation indoors, to a depth of up to 5.5 m below the existing floor level to create space for a new transit concourse and a new lower-level pedestrian retail concourse. A hybrid excavation support system utilizing micropiles as soldier piles was constructed over an 18 month period between 2010 and 2011.Development and testing of connections between the micropiles, shotcrete facing, lagging, walers, and tiebacks presented significant challenges. The existing viaduct structure was constructed in the 1920’s on land reclaimed from Toronto Harbour, so there was significant (and ongoing) uncertainty with respect to buried obstructions including relic timber wharfs and abandoned steel and timber piles. Collectively all these conditions precluded the use of conventional methodology; new techniques, installed using modified equipment, and for the first time in the Greater Toronto Area, were required.Details of the existing site conditions, installation challenges, design, construction and performance of the hybrid excavation support system inside this historic structure are presented.INTRODUCTIONUnion Station in Toronto, Ontario is the busiest passenger rail facility in Canada, with 65 million passengers annually and an average of 200,000 passengers each day. Construction of the station was completed in 1920. It has been designated a National Historic Site of Canada and inducted into the North America Railway Hall of Fame in the Facility and Structure category.The Union Station Revitalization Project (USRP) was tendered in 2010 and awarded as a 6-year, $450M construction management / trade contract package. Included was a large scale grade reduction, referred to as “The Dig Down”, to create two basement levels and this required extensive excavation support constructed entirely indoors within the active station setting."

Jan 1, 2017

By Moto Goto

Today, Pierce-Smith converters, coupled together with various types of smelting units, are used in most of the world's smelters, However, due to the "batch" processing nature, and problems associated with fugitive emissions during the transfer of melt and blowing stages, this arrangement will unlikely be adopted in future smelters. Modern day alternative processes include the Mitsubishi Process, Outokumpu Flash Smelting and Flash Converting Process, the Noranda Process, and the Ausmelt Process, but only the Mitsubishi Process is a "truly continuous" smelting and converting operation, producing a constant flow of blister without tapping, and is economically proven by long term commercial operations. This paper reviews recent advances in modern continuous converting technologies, with a special section devoted to operation of the "first standalone Mitsubishi C-furnace" coupled together with a Noranda Reactor, at Port Kembla Copper Pty, Ltd. in Australia.

Jan 1, 2003

By R. M. Reyes, D. Negrete, G. Herrera

First Majestic Silver Corp’s La Encantada Silver Mine is a producing mine with a capacity of 3,000 tonnes per day. The La Encantada team is currently constructing two small-scale caving mines, including the San Javier breccia caving mine. The new mine is constructed within a mineralized breccia body composed of clasts of varying sizes and with very poor rock quality. Due to this poor rock quality, primary and secondary supports are required to support both the development and production stages. Since the proximity of the new mining levels to existing old workings, correct selection of the support system and proper production controls, instrumentation, and monitoring are very critical to maintain the stability of the pillars and fortification elements. An increased ground deformation due to the load transfer during the production stage is expected. This report reviews the primary and secondary support elements used in the different stages of mining, the monitoring of ground deformation, and the steps taken to analyze and visualize the collected data in order to enable the geotechnical team to manage caving stress and maintain pillar stability. INTRODUCTION First Majestic Silver Corp. (“First Majestic”) is a Canadian mining company focused on silver production in Mexico that operates six producing silver mines, including La Encantada Silver Mine (“La Encantada”). First Majestic acquired La Encantada in 2006. La Encantada is located in the northwestern portion of the state of Coahuila, in northern Mexico, in the municipality of Villa de Ocampo. The mine lies in the northern part of the Sierra Madre Oriental physiographic province. The mine location is shown in Figure 1. La Encantada is a producing mine, with a mill processing capacity of 3,000 tpd, and a 4,000 tpd capacity cyanidation leaching circuit equipped to process fresh underground ore and old tailings amenable to be reprocessed. The mine is currently employing several mining methods, including overhand cut and fill for narrow veins, small mantos, and other minor deposits. A subset of caving methods are applied on the larger, but weak, mineral deposits, such as at the San Javier breccia and La Prieta breccia. La Encantada consists of vein, manto, breccia pipe, and chimney deposits with concentrations of silver, lead, iron, and zinc in oxidized mineralization enclosed by calcareous sedimentary formations of Cretaceous age. At deeper levels, there is sulphide mineralization in skarn with zinc and silver concentrations associated with a granodiorite intrusion.

Jan 1, 2019

"What is your assessment of the minerals business?My experience with mining has been primarily in the coal sector until about 10 years ago, when I also became heavily involved in the aggregates and industrial minerals sectors. I have also had peripheral involvement through family and partners in the gold sector, with just enough exposure to gold to become fascinated. In 1994, I visited Ghana and considered the possibility of taking an expat assignment at a surface gold mine that had just been started.It is not news that the coal sector in this country has suffered tremendously in recent years. Especially hard hit is the central Appalachian region, where a number of factors combined have had a devastating effect on production, jobs and the economy. These factors include federal regulations affecting coal production and use, higher production costs and decreasing market share of Appalachian coal by the switch from lower sulfur coal in favor of lowercost, higher sulfur coal from the Illinois Basin, as utilities have installed scrubbers to comply with Phase II of the 1990 Clean Air Act Amendments. Nationally, the lower cost of natural gas has been a huge factor affecting coal use. In Kentucky, for example, which exports to other states around 70 percent of its coal, those markets are disappearing, as utilities close coal units in favor of natural gas. This is a structural change in the electricity market, and one that will become more pronounced as federal greenhouse gas regulations are implemented.We often hear the phrase, "the war on coal." While there are certainly a number of market factors affecting coal production and use, this phrase captures a different element that is all too real. The attacks have come from environmental activist groups for many years; from some in the media and, in the last few years, from a White House administration that believes strongly in alternatives to coal. Then, there really is an alternative to coal in the form of the previously untapped unconventional gas reserves that allowed utilities to move away from coal.Coal mining will continue in this country. In fact, it appears that our production is holding fairly steady at about a billion tons a year. And predictions that I have seen indicate this will continue for the next few years. What impact the Environmental Protection Agency’s Clean Power Plan will have beyond 2020 is another question.What do you feel is the future of the minerals industry - near term and longer term?Our society depends on the future of minerals in this country being strong. Near term, we are going through some of the typical cycles. Having also been involved in aggregates during the last few years, the business follows government infrastructure projects, such as highway construction and public and private sector development. Those sectors are heavily dependent upon government spending and a strong economy. Increased spending in those sectors, which appears to be on the horizon, should provide additional market shares for aggregates."

Jan 1, 2014

By Aner W. Erickson

"Magnetite iron deposits on Tolstoi Mountain were examined as part of the investigations by the Bureau of Mines of iron and copper ores on Prince of Wales Island. The Tolstoi Mountain project was a part of a program for investigating mineral deposits in Alaska, under the general supervision of R. S. Sanford, acting branch chief.A preliminary examination was made by S. P. Holt, mining engineer of the Bureau of Mines, in company with John Reed, L. A. Warner, and W. S. Twenhofel of the Federal Geological Survey, on July 14, l943. Three samples were taken, rough estimates were made, and it was proposed that the area be mapped, topographically and geologically,. Dip-needle work was added to the program, and it was decided that, should results warrant, the deposits would be diamond-drilled.From March 26 to May 28, 1944, the deposits were examined thoroughly by Bureau of Mines personnel under the direction of the author. Thirty-two acres were mapped with contour intervals of 10 feet, grids were established covering the principal outcrops, over 1,500 dip-needle readings were secured, and the magnetite bodies were outlined. Additional information was gathered by trench inch and channel-sampling, 600 linear feet of trench being dug and 32 channel samples being cut. Finally, the mapped area was checked for nonoutcropping deposits by taking dip-needle readings at 10-foot intervals along the traverse lines, creeks, trails, and all outstanding topographical features. This re-connaissance work gave sufficient coverage of the 32 acres to eliminate the possibility of further magnetite bodies of any consequence remaining undiscovered.Acknowledgment is made to Nile Johannsen, assayer, Territorial Department of Mines, Ketchfkan, Alaska, for determination of samples.The deposits are on Prince of Wales Island in Southeastern Alaska near Tolstoi Pay, a deep-water indentation at the northwest and of Kasdan Peninsula. The physical features are shown on figures 1 and 2 and the location of the deposition figure 3. Old workings were found on the west side of Tolstoi Mountain; between elevations of 650 and 1,150 feet, at distances of 3/4 to 1-1/4 miles from the east shore of Tolstoi Bay.Access to the area is over a brushed foot trail built by the Bureau of Mines. Topography would permit construction of either surface or aerial tramways at moderate cost but would make road building expensive. Deep-water navigation, permitting inexpensive water transportation, is possible the year around.Kasaan Peninsula is an area of moderate relief, being considerably less rugged than the mainland to the east. Most of the mountains and ridges are less than 2,500 feet in height and show evidence of having been covered by the ice cap of the Pleistocene age. Rock exposures below elevations of 2,000 feet are limited, as extensive overburden 2 to 20 feet deep covers the greater part of the peninsula."

Dec 1, 1948

By Neale R. Neelameggham

"Most chemical process plants and metallurgical production facilities have some sort of cogeneration to minimize process energy costs. Use of Alternative Energy Production from sun and wind power with storage can become an integral part of a process plant utility. This will facilitate reduced fossil fuel usage and help minimize thermal emissions. This will be similar to Pollution Control equipment, which have become an essential part of process plants in the past four decades. Conceptual flow sheets of such Process Utility schemes are presented.IntroductionPower is supplied to industries, commercial and residential users. Over the past decade, Electric Utility companies have made major inroads, in introducing alternative energy resources in an attempt to somewhat reduce fossil fuel use in power generation. Now, on a much larger scale than in the early 1980s, residential users, motivated by government provided tax credits, have started installing alternative energy generators such as roof top wind mills or roof-top photovoltaic generators. This will minimize future energy costs, help control thermal emissions etc. This alternative power generation is typically connected to the existing power grid with two way power metering. However, the use of alternative energy generation has not been seen at large industrial sites yet.Paul Scherer Institute, Switzerland and the NREL laboratories in Colorado, are two of the several institutes which have been developing how solar thermal power can be used to supply the endothermic input energy in chemical and metallurgical processes. The theme of this present symposium addresses the above as well as the energy storage needs for such events to become continuous. This paper emphasizes the concept of how alternate energy can be used in the production of materials on a generic sense wherever there is a need for input energy – beyond endothermic process energy - while addressing how to reduce the thermal and carbon emissions.The alternative energy generation using wind or solar source is discontinuous due to the nature of the energy source. They are not only discontinuous but also variable. This necessitates storage of generated power for close to continuous use with variable loads. C Smith, et al pointed out in 2006, that 'the electric power industry has taken notice of the expansion of wind and its potential' in a summary article on integrating wind generation into utility systems.1 In 2009, the 1000 MW wind generation project in Texas had to be postponed to 2013 for lack of transmission.2 There are only a few large MW solar generation units in the US; the projects being slow mainly from lack of adequate storage and redistribution."

Jan 1, 2010

By C. A. Rawlins, P. Rostami

"Ventilation systems are not only an integral part of any underground mine design but are a significant contributor to the mine’s capital and operating costs. The ventilation and cooling design systems presented in this paper were part of the prefeasibility evaluation of an underground platinum mine in South Africa. The mine would ultimately operate at the depth of 1,200 m below surface with a proposed 4 Mtpa production rate. The proposed mining operation is a highly mechanized operation using diesel equipment. Significant daily production rate, large amount of equipment and expansive nature of the operation, contributed to a challenging while flexible ventilation design requirements. This paper presents how to safely and efficiently optimize capital expenditure and operating costs associated with the mine air cooling and refrigeration system through practical ventilation design practices. Successful capital and operational savings by modulating installation and commissioning of refrigeration facilities can influence the economic realization of such systems. The adapted planning and design approach provided a cost-effective advantage while complying with design safety and regulations. INTRODUCTION This paper outlines a prefeasibility evaluation of the heat loads and related cooling system to be employed at the proposed platinum mine. The paper also provides appropriate details for a comprehensive understanding of the applied methodology. The proposed mine will be a trackless underground operation using a combination of mining methods. Initially, ore zones with vertical thicknesses greater than or equal to 18 m will be mined using the long-hole stoping (LHS) method, while thinner ore zones will be mined using mechanized drift-and-fill or drift-and-bench methods; hence, a highly mechanized operation with LHDs, trucks, drill rigs, personnel carriers, etc. is envisioned. Broken rock (ore and waste) will be transported by the means of trucks to the main passes (ore and waste) and collection points. Mining zones identified in the project occur at depths ranging between approximately 700 m to 1,600 m below surface. Primary access to the mine will be via a 1,100 m deep, 10 m diameter production shaft (named Shaft No. 2), three additional shafts will be sunk to provide future ventilation and production support. Three main access levels are established as primary haulage levels and include a series of interconnecting ramps. Additional mining sublevels will be developed as necessary. Figure 1 shows the proposed shaft locations and main access levels in a 3-D elevated view. Mining is performed using highly productive mechanized methods. For this reason, an annual ventilation estimate is based on requirements for mobile equipment (i.e., 0.06 m3/s/kW). The air requirements imposed on the underground operation is further influenced by equipment heat loads, auto compression, and virgin rock temperature, as the main sources of in-mine heat."

Jan 1, 2015

By S J. Schafrik, Z Agioutantis, E C. Jong, K Luxbacher

Real-time monitoring of mine operating parameters is available at most mines. However, access to these data for an individual operation is typically underutilised by mine managers and technical personnel. Such monitoring systems are typically designed to provide data streams and alarms to a responsible person, but they are not utilised to extract underlying trends or correlate different data groups. Furthermore, multiple monitoring systems are usually implemented at a given site without interconnection between vendors’ systems or connection to any central management, and mine personnel are only exposed to a minimal subset of such data. Thus, it is not easy to analyse and correlate individual data streams and generate information to enhance day-to-day operational decision-making and improve safety and efficiency.This paper addresses the primary challenges associated with centralising data management and effecting greater utilisation of the vast amount of collected data, while at the same time reducing the time and effort required to manage such large data sets. Furthermore, it presents the conceptual design of a database application that can organise, present and analyse data collected by multiple sensors in different environments. The database is designed to operate in a passive manner so that active mine data management systems are not impacted. An example is given where this database is used for managing atmospheric data collected at an underground coalmine operation in the US. These techniques have a universal application and can be incorporated in a wide range of mining and construction projects.CITATION:Agioutantis, Z, Schafrik, S J, Jong, E C, Luxbacher, K and Karmis, M, 2015. A platform for managing and analysing atmospheric data in underground coalmines, in Proceedings Third International Future Mining Conference, pp 3–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By José Tealdo Guido

Dado que la Cerro de Pasco constituye la empresa minera que ofrece la mejor visión de conjunto para realizar un análisis o estudio de los problemas económico-laborales en la minería subterránea, no solo por el volumen de sus operaciones, sino también por la extensa área geográfica en la que éstas se desarrollan, el presente texto analiza su contribución como segundo empleador en el país después del Estado, constituyendose el primer empleador de la actividad privada del Perú. Asi también se analiza los aspectos renumerativos de los trabajadores, regulación de la vida, la regulación de la vida laboral y producción hombre.

Nov 1, 1972

By Moto Goto

Today, Pierce-Smith converters, coupled together with various types of smelting units, are used in most of the world's smelters. However, due to the "batch" processing nature, and problems associated with fugitive emissions during the transfer of melt and blowing stages, this arrangement will unlikely be adopted in future smelters. Modern day alternative processes include the Mitsubishi Process, Outokumpu Flash Smelting and Flash Converting Process, the Noranda Process, and the Ausmelt Process, but only the Mitsubishi Process is a "truly continuous" smelting and converting operation, producing a constant flow of blister without tapping, and is economically proven by long term commercial operations. This paper reviews recent advances in modern continuous converting technologies, with a special section devoted to operation of the "first standalone Mitsubishi C-furnace" coupled together with a Noranda Reactor, at Port Kembla Copper Pty. Ltd. in Australia.

Jan 1, 2003

The paper describes a practical methodology based on numerical modelling for the prediction of progressive failure of underground mine stopes with cable bolt support. A case study of the 40-761 stope at Kidd Creek Mine, Timmins, Ontario is presented. The stope was mined by blasthole open stoping in 1986 as a lead stope within a mining block between 36-1 and 38-2 levels. Initially designed to peak at 38-2 level, the stope back caved upwards approximately 40m towards 36-1 level. Cable bolts were installed above the stope from 36-1 level after caving had begun. The stope eventually stopped to cave when the falling rock mass encountered a sufficiently high cable density. The paper provides details of the geomechanical data and modelling results of the case study. Numerical modelling is carried out using a finite element package known as e-z tools which has, among other things, a special cable/rockbolt simulation capability.

Jan 1, 1994

By R. J. Craig

Introduction All mining operations produce rock dust. Inhalation of rock dust, particularly if it has a high silica content, causes silicosis. Silicosis is, therefore, recognized as a hazard of the mining industry and has been made compensable throughout most of Canada. Most of the dust in any mining operation is caused by rock drilling and blasting operations and the movement and transportation of broken rock. Dust from blasting cannot be eliminated, but it can be controlled by means of increased ventilation, the use of water sprays, and the control of blasting hours. Dust from ore movement can be reduced by keeping the broken rock in a moist condition at all times. The dust from the rock drilling operation has been found to be the most difficult to control. Concentrations of dust caused by rock drills in stopes can usually be reduced to the safe minimum of 300 particles per cubic centimeter (p.p.c.c.) by diluting the air with increased ventilation. In development headings, where the machines are more confined, this is not always practicable. Therefore, the dust must be eliminated at its source. This paper deals with the reduction of dust from Leyner machines by adopting improved designs.

Jan 1, 1947

By Barton, Donald C.

THE elastic, earthwaves produced naturally by earthquakes -have been used for a long time as evidence from' which to draw conclusions in regard to the constitution of the interior and crust of the earth. The elastic earthwaves produced artificially by occasional explosions and recorded by seismological .observatories were used to draw conclusions regarding the-geology of the intervening area. Intentionally produced elastic earthwaves in the past five years have come to be used extensively in the investigation of very local geologic structure. The seismic method of working geologic structure, which makes use of artificially controlled explosions and the resulting earthwaves, has developed almost `clairvoyant power in handling certain geologic situations, and in the discovery of salt domes in the Gulf Coastal: Plain region of Texas and Louisiana has 'scored the, most brilliant success.

Sep 1, 1928

By G. C. Amstutz

The topic of the industrial applications of mineralogy is a vast field which can be adequately covered only in a large book or by a two or three semester course. This paper recalls experiences of the writer in this field, a task requested by the Process Mineralogy Committee. Therefore, this paper is largely an account of the industrial mineralogy problems I was involved with, since my student years, Although I will treat each application only briefly, it is hoped that they will illustrate to the students in the field how varied are the applications of mineralogical methods. In this respect, I want to emphasize that it is important for mineralogy teachers to point out the usefulness of mineralogical methods much more often in their courses. Not only does that help prepare young individuals for industrial careers, but also it arouses their feeling of consciousness of public responsibility which is an important attribute for the world's scientists. When professors utilize the varied applications in their teaching of mineralogical methods students then understand better the significance of learning those methods and appreciate the many years of necessary university preparation. The first time I was involved in an application of mineralogical methods was about 1944 as a student of Professor Paul Niggli. He was asked to study the problems of ice crystallization on wings of airplanes. The ice formed at high altitudes and during the winter. This was not outside his realm of expertise because he was the main initiator of the Snow Research Institute on the Weissfluhjoch in Switzerland. I believe that the work of this Institute was an important factor in stimulating much of the snow research subsequently carried out at the United States Army Snow Research Center, which was located at that time in Willmette near Chicago. Dr. Bader, one of Paul Niggli's former students, was the Director of Research at Wilmette at that time and for quite a number of years thereafter. A mineralogist-crystallographer can make important contributions to a better understanding of the problems of snow and ice formation, avalanche hazards, and the prevention of hail. The habits of snow crystals are essentially a function of the temperature and the humidity,

Jan 1, 1982

By R. V. Ramani, R. Bhaskar

"The spatial distribution of airborne dusts, deposition of dust in the airway, as well as the effect of airflow velocity and particle density on dust behavior in mine airways were studied in a set of experiments performed in a mine airway under controlled conditions. Considerable deposition of dust near the source was indicated. Pronounced effects due to velocity were observed in ambient dust concentration and deposition along the mine airway, both in the respirable and the total size ranges. Cross-sectional concentration measurements indicate an increase in concentration from the roof to the floor. The average cross-sectional concentration is about 75% of the concentration in the center of the airway.IntroductionA number of studies have been performed since the early 1950s on the behavior of dust in mine air (Bradshaw and Godbert, 1954; Dawes and Slack, 1954; Bradshaw et al., 1954; Hall, 1955-56; Reinhardt, 1971; Ford, 1971; Courtney et al., 1982). While the experimental data available from these studies are indeed useful in understanding dust cloud behavior in a specific situation, no generalized conclusions can be drawn because of the lack of data on parameters such as flow velocity, size distribution of the source dust, and particle density. These change from mine to mine or even within the same mine. The present study is aimed at providing a better understanding of the temporal and spatial behavior of dust particles in underground mine airways (National Academy ofSciences, 1980). The characteristics studied encompassed airborne concentrations and floor depositions over the entire size range as well as the respirable size range. The experimental results in this paper are intended to complement a mathematical model developed to predict ambient concentration and deposition of airborne dust in mine airways (Bhaskar and Ramani, 1986)."

Mar 1, 1989