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By Wojciech Klecan

Cobb County, located on the northwest side of Atlanta, GA, is continually growing and, like many other metropolitan areas, it needs to increase the capacity of its waste water system to meet future demand. The Cobb County Water System (CCWS) is the responsible agency for water distribution, waste water collection and treatment in most areas of the county. CCWS, one of the most progressive agencies in the metro-Atlanta area, is addressing its future waste water capacity needs in the southern part of the county with the construction of the South Cobb Tunnel and Pump Station. This project consists of an 8.8-km- (5.5-mile-) long, 8.2-m- (27-ft-) diameter, tunnel boring machine (TBM) excavated waste water storage and conveyance tunnel; six tangential vortex-flow intakes ranging from 1,533 to 5,700 L/s (35 to 130 mgd) peak flow capacity, two construction shafts, six 1.8-m (6-ft) finished diameter connecting tunnels ranging in length from 6 to 975 m (20 to 3,200 ft) and a 5,700-L/s (130-mgd) wet/dry pit pump station. The pump station will have a semi-circular wet well with a dividing wall that extends almost to the top of the shaft and a spilt dry well for reliable operation. Roller gates will control the flow to the wet well from the tunnel. The pump station will have six 1,420 L/s (32.5 mgd) pumps and two sets of stair wells and elevators. With a finished diameter of 32 m (104 ft) and a depth of 62 m (204 ft), this is the largest pump station shaft constructed so far in Georgia for the dewatering of a waste water tunnel. The pump station shaft was also the highlight of the well attended and successful 2009 Shaft Design and Construction Short Course held in Atlanta, Sept. 10-11. The two-day course was sponsored by the Underground Construction Association of SME and Pennsylvania State University and concluded with a field trip to the pump station shaft. The tunnel starts south of the city of Austell and finishes at the South Cobb Water Reclamation Facility (WRF), located on the banks of the [ ] Chattahoochee River just north of Interstate 20 (Fig. 1). The South Cobb Tunnel will run 30 to 137 m (100 to 450 ft) below the surface, with an average depth of about 91 m (300 ft), through metamorphic rocks (Fig 2). The construction contract was awarded to Shea-Traylor JV with the lowest bid price of $305 million and notice-to-proceed was given on July 14, 2008. Jordan Jones & Goulding, Inc. (JJG) is the project designer and performed the geotechnical investigations. Parsons/Jacobs Associates is the construction manager. The South Cobb Tunnel is CCWS?s second deep hard rock tunnel. The 15.3-km- (9.5-mile-) long, 5.5-m- (18-ft-) diameter TBM excavated the Chattahoochee Tunnel was the first deep tunnel to be construced in Cobb County. Construction began in 2000 and the project was completed four years later. It is located about 16 km (10 miles) northeast of the South Cobb Tunnel in similar geology. It was designed by JJG to meet east Cobb?s long-term waste water capacity needs and provide flow equalization to the R.L. Sutton WRF. The Chattahoochee Tunnel was named ?Outstanding Civil Engineering Project of the Year? by the Georgia Sec-tion of the American Society of Civil Engineers in 2006.

Jan 1, 2009

By H. J. Sutherland

This paper reviews the results of the subsidence research prop ram at Sandia National Laboratories. The manuscript highlights the following: the application of empirical methods (profile functions) to the subsidence above longwall panels in the U.S.; the use of the "rubble model" to describe the behavior of broken strata as it distends when it falls to the Mine floor (or top of the rubble pile) and then is subsequently compacted as it is loaded by overlying elements of strata; and, the application of physical modeling techniques (centrifuge simulations) and numerical techniques to study the failure mechanisms in highly structured stratigraphy. The capabilities of the latter two are illustrated ')y comparing their predictions to the results of a field case that has complicated stratigraphy.

Jan 1, 1982

The ore treatment expansion programme at Mount Isa Mines required the erection of a new lead-zinc concentrator to be known as No. 2 Concentrator. This concentrator was designed by Western-Knapp Engineering Company in conjunction with staff of Mount Isa Mines Limited. Metallurgical design followed conventional wet milling practice, but the size of many plant units is larger than previously used at Mount Isa. The. total capacity of the new plant is 150,000 tons per four weekly period, and the plant is designed to operate in two equal parallel sections.Erection was contracted on a turnkey basis, and the plant was commissioned as a production unit on 23rd June 1966.The existing concentrator, No. I, was converted to treat all copper ore, and the total capacity of the two plants is now 390,000 tons per four weekly period.

Jan 1, 1968

AMONG the multifarious duties which fall to the lot of a mining engineer it is safe to say that there is none of more fundamental importance than the study of the ore-deposits on which it is thefunction of his profession to operate, inasmuch as the whole business of mining in all its complicated ramifications rests first of all on the existence of something to mine. -When the ore supplies in a mine fail, the enterprise comes to- an end, and nothing, therefore, is of more importance than a thorough understanding of the conditions under which the ore occurs, so that everything possible may be done to open up the mines well ahead of their immediate output requirements, and develop new ore reserves to take the place of that which is raised from day to day. The great aim which the mining engineer has to keep before him in his study of his ore-deposits is to obtain such a knowledge of them that he will have sound grounds for prediction as to how they will behave in parts of the mines which are well beyond the point of the pick. It is on his judgment of probabilities in this respect that mining operations are entered upon, and the more thorough his knowledge of all the factors affecting the problem, the more is the judgmentlikely to be a sound one. The test of any theory is experimental confirmation of the truth of predictions based upon it, and our aim should be to try to perfect our knowledge of the rules governing deposition of ores, so that our theories may prove themselves equal to the task of successful prediction.

Jan 1, 1909

By B. Goard

"IntroductionCemented backfill has been placed underground in slurry form in Inco Limited's Ontario Division mines since the early 196Os. The slurry was traditionally mixed on surface at between 65 and 70 wt% solids* and transported underground via gravity through a borehole-pipeline distribution system. This method of placement, while simple and dependable, has proven to be costly because of the large amounts of transport water involved.A significant quantity of the slimes buildup on mine levels is caused by the backfill water carrying cement and other fine material out of the stopes. The level cleanup and eventual pumping or hoisting of the slimes and water back to surface result in substantial indirect backfilling costs.The cement that remains in the stope is always overhydrated because of the high water cement ratios that exist. As a consequence, high concentrations of Portland cement must be added to the backfill to produce the fill strengths required for the different mining methods.Pouring backfill at these densities also demands extensive fill preparatory work in the stopes to withstand the hydraulic heads created by the slurried fill. This, along with the delays in pouring necessary to allow for water drainage, result in significant losses in productivity.These negative aspects of slurry placed fill has led Inco Limited to investigate several methods of transporting backfill underground via pipeline, at higher densities (i.e. 75 to 95 wt.% solids). Three separate transport methods are presently being experimented with by the Company's Mines Research Department. Each utilizes a different technique or form of flow transport, i.e. concrete pumping technology, high density slurry flow, and pneumatic conveying."

Jan 1, 1987

By G. K. Jorgenson, S. H. Chung

"IntroductionThe SABREX Blast Modelling Program was developed jointly by the companies of the ICI Explosives Group, of which C-I-L Inc. is a member. SABREX (Scientific Approach to Breaking Rock with Explosives) is a modular computer program which incorporates new technology with a number of tested programs that have been in use world wide.SABREX predicts the performance of blasts in terms of (I) fragment size and distribution; (2) muckpile profile and face velocity; (3) grade fracture; (4) collar breakage; (5) a rupture envelope which depicts crack penetration behind and beneath blastholes; and (6) a complete cost analysis including explosives, drilling and accessory costs. The predicted blast results are displayed as dynamic colour graphics and in tabular form.SABREX uses data on the detailed geometry of the drilled and loaded pattern, detonation characteristics of the explosives and the dynamic properties of the rock to generate blast predictions. SABREX blasting calculations take into account the effects that shock and quasi-static pressures exert on the rock around the blastholes. While physical effects occur very rapidly in rock blasting, it is possible to view and model the sequence of events as discrete sections.The program can be run on a microcomputer and is currently operated by C-I-L technical service staff in Canada for the use of drilling and blasting operators.Figure I is a diagram representing the modules of the program and associated technology that is used to complement the program.Any, or all, of the modules may be used in a particular study or blast optimization. Because the BOBCAT module of the SABREX program has been described in previous papers(7.8.9), this discussion will concentrate on the newer modules: CRACK, HEAVE, RUPTURE ENVELOPE and to a limited extent, KUZ-RAM, which present a more detailed picture of the blasting process.Each of these modules is discussed in terms of the information they offer the operator in analyzing the blast. Specific examples of recent usage in Canadian mining situations are included to illustrate the ability of the model to produce practical results that can assist in optimizing actual blasting operations or solving problems that do exist."

Jan 1, 1987

By L. F. Elkins

In 1946 Littlefield, Gray and Godbold published a thorough geologic description of the West Edmond Hunton Lime reservoir, located in Central Oklahoma, and discussion of its early performance.l They stressed implications of the nature of the reservoir rock on performance to be expected with production both by natural means and by pressure maintenance with gas injection. The essence of their analysis was that presence of an extensive interconnected system of fractures and solution channels constituting about 10 percent of the total reservoir void space in otherwise very low permeability reservoir rock would result in severe channeling of naturally encroaching water or injected gas through the fractures with little or no benefit to ultimate recovery of oil. Considerations were in progress to unitize the reservoir for pressure maintenance by gas injection. Some other engineers involved in the project had considerably different opinions at the time regarding continuity of fractures and regarding effects of such fractures on performance. The field was unitized Oct. 1, 1947. Subsequently, pilot gas injection tests were conducted in four areas of the field; large scale waterflooding was conducted in two parts of the field in the Bois d'Arc or Upper Hunton; and pilot waterflooding was conducted in the Chimney Hill or Lower Hunton. Full scale water-flooding is now in progress in the Chimney Hill section where it is oil productive. The primary purpose of this paper is to divine some of the secrets of this reservoir through analysis of all aspects of its performance, with the hope that it will be of help to engineers and operators in developing and operating other low permeability fractured reservoirs. In part, this considers variance of actual performance from some widely used conventional reservoir engineering assumptions. For brevity, other aspects of unit operation and its benefits to the owners are not discussed. Oil and Gas in Place For unit participation, net pay in the Bois #Arc defined by the gross SP anomaly on electric logs totalled 2,100,000 acre-ft in the 30,000-acre reservoir. Development of West Edmond predated modem logging techniques that now would be used to determine "net" or "productive" pay. In Fig. 1 this log pick is compared with detailed core analysis and core descripfion by Littlefield et a1.l for one well identified as A on the index map in Fig. 2. Not all of the gross Bois #Arc section had oil staining, but all cores with measureable intergranular permeability were stained. (The committee selection of the Bois d'Arc SP interval also includes the Frisco section as identified from cores by Littlefield.) The Bois d'Arc is oil productive throughout the entire 600-ft monoclinal accumulation from the eastern upstructure erosional pinchout to the west-side oil-water contact. (See Littlefield et al.l and McGee and Jenkins for geologic detail.)

Jan 1, 1970

By N A. Sikwa, L M. van Niekerk, G N. Ndlovu

In June 2012, Lucara Diamond Corporation officially commissioned its Karowe Diamond Mine in Letlhakane, Botswana. The processing plant circuit incorporates variable speed autogeneous milling, a first for African diamond processing - only previously practiced in Russia. The paper discusses the basis for the selection of milling against the more traditional circuits incorporating crushing and scrubbing. It covers early commissioning challenges of operating a mill in an æalien environmentÆ with no immediate reference plant to look up to for bench-marking.The paper describes how these challenges were overcome and learnings quickly incorporated into the mill operating philosophy for maximum diamond liberation and minimum product damage. The plant was commissioned in three months and by August 2012 the production ramp up had reached name-plate capacity. The feed to the mill has varied from highly weathered material to extremely hard kimberlite and the operating philosophy had to be optimised for the full range of ore types. While more work is required to stretch the mill operating envelope coupled with other circuit additions to improve liberation of fine diamonds at minimum capital expenditure, the mill has, to date, performed to its billing.CITATION:van Niekerk, L M, Ndlovu, G N and Sikwa, N A, 2013. Commissioning and operating an autogeneous mill at Karowe Diamond Mine, in Proceedings MetPlant 2013 , pp 215-228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By G. D. Schena, M Zanin

A numerical approach is presented for predicting the liberation of phases during comminution, with direct calculation of a liberation spectrum giving the fraction of the particulate system in each narrow size-composition class. The numerical model uses a Poisson flat process for stochastic generation of the non-convex three-dimensional Poisson polyhedral textures and the system of fractures that give rise to convex fragments. With this numerical approach, there is no need to assume random uniform isotopic fracture (lack of selective liberation); only computational geometry primitives are exploited for the derivation. The agreement with relationships obtained previously under the random uniform isotopic fracture hypothesis demonstrates that the approach is capable of deriving full liberation spectra directly. Both volumetric and superficial composition can be calculated

Jun 21, 1905

By N. Niemuth

Strong demand for copper in developing nations such as China and India, plus the additional demand for industrial minerals to supply the Arizona construction market, brought about a record-setting year for the state?s mining industry. The value of Arizona?s copper production set a new high of $5.5 billion and pushed the total value of mineral production to $7.58 billion. This was also a record. As it has for many years, Arizona ranked first in nonfuel mineral production in the U.S. In addition to leading the nation in copper, Arizona ranked in the top five in molybdenum, sand and gravel, gemstones, perlite, silver, zeolites and pumice. Generally strong and rising prices, especially toward year?s end, fostered a bullish atmosphere that encouraged significant levels of acquisition and exploration. This activity has spread beyond the normal commodities to include some, such as manganese and fluorspar, that have not been mined in Arizona for decades.

Jan 1, 2008

In a gravity separation device, particle shape, size and density all play a role. The combination of these determines where each individual particle reports to in the viscous fluid, where particle crowding (solids to water ratio) also plays a role. To understand the performance of gravity separation devices in the heavy mineral industry, these particle characteristics need to be measured. There are various challenges in analysing particle density and particle size simultaneously for the purpose of quantifying gravity separator performance, not to mention particle shape. These analytical challenges include the high cost of high-density sink-float fractionation, toxicity of high-density sink-float media, inability of sink-float media to fractionate at densities greater than 4.0 g/cm3, and the time-intensive nature of these fractionations. The use of the detailed particle-by-particle output from Qemscan® particle mineral analyses (PMA) as a fast and cost-effective alternative is evaluated. The size and density outputs from the Qemscan® were employed to characterize the performance of a heavy mineral spiral concentrator as an example. Critical analytical requirements are to be addressed before the Qemscan® output data can be utilized. Keywords Gravity separator, performance, heavy minerals, Qemscan® particle mineral analysis

Jan 1, 2011

By H. M. Lawrence

"Florida, the State that supplied 82 per cent of the phosphate rock sold in the United. States in 19284, has two producing areas - the hard-rock and the land pebble districts. Production of the hard-rock field, decreasing importance in recent years, is now confined to mines near Dunnellon, in Marion and. Citrus Counties. The land-pebble district, with a production of almost 80 per coat of the nation's requirements, is located, in Polk and Hillsborough Counties. In the land-pebble area the phosphate deposits - probably Pliocene in age, derived by marine action from underlying, older, phosphate-bearing formations - consist of beds of phosphate matrix, covered by practically barren sands and clays. The overburden, ranging in thickness up to 45 feet, is removed by hydraulic methods or by drag-line excavators. The matrix, ordinarily less than 25 feet in thickness, is mined by hydraulicking and is pumped to adjacent washing plants for beneficiation. The dried product of the washing plants is the Florida pebble rock that is sold in foreign as well as domestic markets.The beneficiation of phosphate ores in the land-pebble district of Florida has been largely limited in the past to the recovery of the coarser pebbles. By washing and screening the crude matrix a separation is effected at about 20 mesh (0.033 inch). The coarser material is the phosphate-rock product of the plant and the finer material is discarded. The amenability of the washer- rejects to treatment by other processes is being investigated. Of methods that may have some application to the treatment of the low-grade phosphatic sands that comprise the greater portion of the washer-rejects, gravity concentration has received some study.Laboratory experiments to determine the amenability of phosphate sands to gravity methods of concentration were first performed in October, 1927. Later, in the winter of 1928-1929, a further series of teats was made,. In these later tests phosphatic sands were concentrated by hydraulic classification, and. also by hydraulic classification followed by tabling. In these experiments concentrates with an analysis above the minimum grade of commercial phosphate rock (66 per cent bone phosphate of lime - B.P.L.) obtained. The recovery of the phosphate varied but was promising enough to warrant further study. A more comprehensive investigation was therefore outlined. This paper presents the results obtained from an investigation, of classification and tabling of phosphatic sands recently completed by the United States Bureau of Mines Su cooperation with certain Florida phosphate companies, the Missouri School of Mines and Metallurgy, and the University of Alabama."

Jul 1, 1930

By P Papanastasiou, J Hadjigeorgiou, E Kyriakou

The south west area of Cyprus has a long history of slope instability problems. The location and extent of these landslides has been influenced by ground morphology, geological structure and the presence of weak rocks and cohesive soils. The main triggering mechanisms have been precipitation and/or seismic events. Landslides have contributed to the decision to relocate villages and considerable efforts have been put into maintaining the integrity of the local transportation network. This paper uses a recent case study of road embankment failure near Pentalia in southwest Cyprus to review the available tools for the analysis of slope instability. It further demonstrates how the shear strength reduction technique can be used in a finite element analysis to better visualise the slope instability mechanism of a road embankment and provide a reliable tool in selecting appropriate remedial measures.

Jan 1, 2006

Tunnelling under squeezing ground conditions poses significant challenges. There are fundamental differences in the choice of support for mining as opposed to civil engineering. This paper reviews ground support strategies that have been used to control large deformations in mining excavations based on field data from five different mines in Australia and Canada. Recommendations are made for improved ground control strategies in squeezing rock conditions.

Jan 1, 2008

By C. M. Davidson, D. J. Drexler

"Sulphuric acid treated with hydrogen peroxide to destroy organic contaminants could conceivably show increased corrosivity toward carbon steel shipping and storage vessels, caused by the persistence of a peroxide residual. This paper describes work performed to determine the effect of 0-200ppm hydrogen peroxide on the corrosion of carbon steel by 93% and 98% sulphuric acid at room temperature (23ºC) and 50ºC.Steel electrodes were exposed to acid containing several peroxide levels (0. 45, iOO and 200 ppm) for up to two weeks. Specimens were removed at intervals and weight loss, open circuit potential, depth of metal loss and residual peroxide concentration recorded.Hydrogen peroxide decomposes considerably over two weeks in iron-contaminated sulphuric acid. initial peroxide concentrations > l00 ppm suppress corrosion, but the effect is lost when concentration decays below about 60 ppm. Sustained peroxide levels in the range below 60 ppm may increase corrosion rates. These phenomena are interpreted by analogy with anodic passivation."

Jan 1, 1987

By W. Barnett

The Limpopo Metamorphic Belt is a complex geological terrane with at least three major deformational events. Tectonically juxtaposed lithology, open to isoclinal folding, crosscutting and re-activated shear zones and metamorphic gneisses and schists make pit slope design and maintenance a risky business. Venetia diamond mine?s Cut 3 is planned to reach 360 m by 2011. The difficult rockmass created problems in the original pit and a new more comprehensive slope design was necessary. Nearly 9 km of geotechnical drilling were undertaken to produce a new geological model and provide geotechnical information near the final Cut 3 face. All existing data from the pit were brought together into a database. SRK Consulting were brought into the project to audit the process and provide most of the manpower for the data analysis. Existing failures were back-analysed and the geotechnical domains identified. Analyses of only the southern domains are discussed in this paper. Geotechnical engineers can design slopes at any angle, but it is up to the managers at the mine to decide what risk they are willing to accept in a slope design. Once the issue of risk was discussed and settled in respect of the consequences of failure, each of the main geotechnical domains were analysed to produce a slope design at5% probability of failure with 15% above the first ramp. A risk assessment of the design was then undertaken to determine what risk the design placed on the equipment, personnel and the profitability of the overall mining operation. The risk assessment indicated minimal risk to the operation. One of the main assumptions of the final design is that the pit slopes will be dewatered. A project was immediately put in place to determine a groundwater model for the mine and to thereby determine the best dewatering procedure. However, it should be obvious that it is practically impossible to prevent benches from getting briefly saturated with water during storm conditions. It was therefore necessary to look specifically at supporting the crests of the ramps in the problematic southern domains to guard against the possibility of crest failure during heavy rains. The data available were re-analysed toward this objective. Spiles were recommended as the most cost-effective support system, and a probabilistic approach was used in the design. The final design has a 5% probability of failure, and the analyses indicate a strong sensitivity of the required spile spacing to the strength of the reinforcement material that will eventually be used. The pit slope parameters derived as per the discussion in this paper have just begun to be implemented at Venetia Mine.

Jan 1, 2001

By Stone. Jon P.

INTRODUCTION Countries that are currently developing their mineral potential have unique information systems requirements to support these activities. The mining laws usually grant the State considerable authority over the process. In many instances, the mining laws give a government agency the responsibility for granting and controlling exploration permits and development concessions. This is the case in Costa Rica. The Direcion of Geologia, Minas, y Hidrocarburos (DGMH) of the Ministerio de Industria, Energia y Minas (MIEM) is responsible for the management and operation of the National Mining Register. This paper describes the results of two studies of the information system requirements to support the National Mining Registry as well as those supporting some of the other function of the DGMH. The first of the studies reviewed the situation before the installation of computer equipment. The second study evaluated the installed systems. BACKGROUND Historical Perspective Mining in Costa Rica is at present a relatively minor part of the economy. It consists primarily of industrial minerals and gold production. Gold production is largely by small-scale miners and may be more substantial than reported. There is considerable interest on the part of the Government in both having a better understanding of the existing mining industry and promoting future development. Mining law was first provided by the Ordinanza de Mineral (of 1830). This was replaced by the first Mining Code of 1953. Apparently, one of the first problems caused by the 1953 law was the granting of concessions which were not worked. A 1968 agreement with ALCOA also resulted in political conflict. The Government worked on a new Mining Code for many years and in 1982 the current Mining Code was enacted. Draft implementing regulations were prepared in April 1984. Mining Code of 1982 The Mining Code of 1982 addresses most aspects of mining in Costa Rica including the declaration that all mineral resources are to be the property of the State. The State may grant exploration permits and exploitation permits. The exploitation of hydrocarbons, radioactive minerals and certain water resources was reserved to the state. The DGMH was given authority to settle placer claim disputes, maintain a registry of exploration permits, and exploitation concessions. and generally supervise mining activity. Towards this, the Mining Code of 1982 includes rather detailed requirements for the processing of application for permits and concessions. Mining Code Application Requirements The following briefly describes the requirements to give the reader a feeling for the complexity of the process. Currently, over 1,000 active applications, exploration permits and exploitation concessions are being monitored under the process. The number remains relatively consistent in that the number of new applications is usually about the same as the applications that are put aside. The time and date of the filing must be certified by the DGMH. The application must include all the information specified in the Mining Code. If incomplete, DGMH must notify the applicant of the deficiencies or omissions and direct that the applicant correct the deficiencies or omissions within 8 business days (a single 30 business-day extension is allowable). If the applicant does not respond as directed, the application is deemed as not having been filed and the pertinent information is placed in the files. The DGMH must reject the application outright and direct it be placed in the files in the following cases: (a). If the new application covers the area of a previous permit or concession, either being processed or already granted.

Jan 1, 1987

By B. Clermont

Ball mills are usually the largest consumers of energy within a mineral concentrator. Comminution is responsible for 50% of the total mineral processing cost. In today?s global markets, expanding mining groups are trying to optimize mill performances. Since comminution is concerned with liberating valuable minerals for recovery in the separation process, it is crucial to run the mills at the best operating conditions which lead to good liberation at competitive throughputs with minimum costs (energy and wear). The high availability of the equipment is also essential to maximize production and profit. To reach this key objective, continuous and reliable information about the mill operation is vital. An innovative tool which can deliver information about in-mill dynamics has been developed by Magotteaux. It can provide online and accurate measurements of the degree of grinding ball fill and pulp position for timely decision making and actions. This tool could be used on its own or linked to an automatic grinding ball loading system named Magoload. Therefore, ball load could be kept constant by using direct measurement. This article describes the Sensomag and presents some of the major improvements that can be achieved with it. Some other promising avenues are still to be explored. Keywords: Comminution, process control, process optimization, process instrumentation, online analysis.

Jan 1, 2010

By Thomas Novak, Sampurna Arya

Controlling dust generation and keeping it below permissible limits to meet federal dust standards at the working face of a roomand-pillar coal mine is a challenge for a mine operator. With the recent changes in federal dust regulations requiring lower worker exposure, maintaining compliance has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the National Institute for Occupational Safety and Health (NIOSH) indicated that a flooded-bed scrubber could achieve cleaning efficiencies between 58 and 90%. But, the operation of such a system is maintenance intensive. The flooded-bed scrubber screen becomes clogged with dust particles and requires frequent cleaning to maintain performance. However, the dust control issue is not solely a mining industry problem. Other industries face similar issues. The University of Kentucky collaborated with Toyota Motor Manufacturing on the development of a novel wet scrubber, called the vortecone scrubber, for capturing oversprayed paint particles in automotive paint booths. The vortecone scrubber achieved a cleaning efficiency of 99% and required minimal maintenance. This study aims to assess the ability of this vortecone scrubber to capture respirable dust in an underground coal mine. The paper presents the results of computational fluid dynamics (CFD) modeling of this vortecone scrubber. It discusses the effects of air quantity and dust particle size on the performance of the scrubber.

By Maurice Bottiau

It is a quite challenging objective to aim at covering in one paper the most recent evolution in piling and deep foundations technologies. This report has to be understood within the limits of the session 2b. It will therefore concentrate on the technological evolution of deep foundation techniques, addressing design issues only when directly related to execution aspects. For the same reason, it will not address the related codes, as a separate session of this conference is specifically dedicated to this topic. Monitoring and deep excavations being covered in other sessions, they will only be addressed when clearly relevant. We will try to show, from a practical viewpoint what are the main changes and the most exciting or critical issues over the last years, as they appear from the topics addressed in the literature or in the papers published in this session of the conference. As the paper mostly intends to explain trends and critical topics, it cannot be exhaustive, neither can it give the full description of the case studies. The author invites the reader to read the full papers, for a more complete description. We have divided our report in three main topics: Piling, soil improvement and treatment and retaining walls. Anchors and tie-backs will not be treated, neither tunneling.

Jan 1, 2006