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By G. Adachi, K. Machida, T. Ozaki, K. Murase

The chlorination rate with CCl4 was unexpectedly slower than carbochlorination using chlorine under the same reaction conditions. Chlorination with CCl4 was topochemical and the amount of monazite reacted after different periods suggested that the kinetic control step was the reaction between CCl4 and the monazite core at the interface. The kinetic order of the reaction was 0.5. The presence of a complex former, AlCl3, promoted the chemical vapour transport of rare-earth chlorides as complexes

Jun 18, 1905

By M. Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

Jan 1, 2005

By R. Mckinstry, M. Rantapaa, T. Bolles

"Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput.Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore.Barrick Goldstrike’s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs."

Jan 1, 2005

By Christopher Mark

The first International Conference on Ground Control in Mining opened with the topic of pillar design. Two classic papers were presented, one by Bieniwski and the other by Wilson. Unfortunately, the two methods were so radically different from each other that it was nearly impossible to reconcile them. Adding to the confusion were the many other pillar strength formulas (such as the Salamon-Munro, the Holland-Gaddy, and the Obert-Duvall, just to name a few) that were also available. Little wonder that discussions of pillar design in those days often ended with anguished cries of ?but which formula is the right one?? The past 25 years have seen substantial progress in the science of coal pillar design. Indeed, one testament to the improvement is the relative scarcity of papers on the topic at recent Conferences. Two factors have been largely responsible for the progress that has been made. The first has been the collection of large data bases of actual case histories of pillar performance in a variety of settings, from shallow room-and-pillar mines through deep cover longwalls. These have made possible the development of empirical design procedures that are closely linked to real world experience. The second important factor is the development of sophisticated computer models that can accurately simulate pillar behavior and roof/pillar/floor interactions. Together, these two lines of research have led to a new understanding of pillar mechanics that identifies three modes of pillar failure: ? Sudden, massive collapse, accompanied by airblast, for slender pillars (width/height<4) ? Squeezing, or slow, non-violent failure, for most room and pillar applications (4<w/h<10) ? Entry failure or bumps for deep cover and longwall applications (w/h>10) It is particularly satisfying that the insights gained from numerical models broadly support those obtained from the empirical studies. While far less controversial than in the past, pillar design problems continue to arise. One recent example is pillar design for highwall mining. NIOSH has just released a software package, called ARMPS-HWM, which employs a number of modern pillar design concepts. Since highwall mining web pillars are long and slender, the greatest danger is that of a sudden collapse. ARMPS-HWM suggests two possible prevention strategies, one which concentrates on the SF of the webs, and the other which creates a ?pressure arch? using properly sized barrier pillars. The paper will close with a discussion of some current needs in coal pillar design, including: ? Updating older empirical methods, such as ALPS, where changes in technology (new types of roof support, more demanding ventilation requirements, faster retreat rates) may have made some of the original case histories obsolete. ? Methods for determining site-specific coal strengths, focusing on bedding plane strength and other factors that may effect confinement, as input for both empirical and numerical design. ? Improved methods for evaluating coal pillar performance for environmental issues, such as surface subsidence and hydrologic impacts, which consider such factors as depth, w/h ratio, water immersion/drainage, and time dependent seam strength.

Jan 1, 2006

By H. B. Humphrey

[EXPLOSION of gas and dust in coal mines, have caused death t lid injure to mines, and destruction of workings in all countries where coal is mined underground. In the United Stales the first reported explosion wits in Min; explosions have continued to the present. The danger to film ill it mine When an explosion occurs in not always measured by the violence created or by their nevi lies, to the area through which flame and Violence extend. As many, perhaps more, risen have died from gases and lade of oxygen (known as "after-damp") than have been killed by the blast and hart. Me explosions often are caused by it combination of factors, including concentration of methane in air, formation of clouds of dust, and the presence of a flame or spark. These explosion factors have varied with changes ill milting method and practises over the years, but the basis causes have always been the salve. Understanding of the causes and to acceptance of ways to guard against explosions and their effects have been slow to spread from investigates to officials and Own to bosses and miners. To a considerable extent there hats lawn a belief that explosions were a joining risk but might hr, put oil hut could not be presented. Such belief is based on the human failure to maintain and observe necessary precautions. These failures, caused by inertia to change, carelessness, or reliance on continuance, of past explosion-free years, are being reduced in number and effect by education of miners and supervisors and acceptance of higher prevention standards.]

Jan 1, 1959

By B. J. Clauzier

"The Falconbridge Limited approach to employing communication equipment is first, to determine what is required in a given situation, second, to evaluate the possible alternatives, third, to select the most suitable hardware and, fourth, to determine what modifications, if any, are required to ensure not only successful implementation but continued low-cost reliability. Two examples are examined.The first situation required remote video monitoring of an acid loadout station. Several alternatives for linking to theremote site were investigated, including hard-wired, slow-scan and microwave. A comparison of these alternatives is shown and an appraisal of the performance of the selected microwave link is presented.The second situation required direct voice contact between the two members of an underground tram crew. Alternative solutions are described and an evaluation of the selected system- SHF portable radios - is presented.ObjectivesIn general, projects must have four main objectives: (1) to improve the safety of its operations; (2) to reduce its operating and capital costs; (3) to increase the efficiency of its work force; and (4) to increase its productivity. ScopeCommunication, when used wisely, can be a good tool to achieve these objectives. Projects can be kept simple using existing technology and adapting it to a particular task. To ensure the success of the project, it was necessary: to determine the project objectives; to evaluate the possible alternatives; to select the most suitable hardware; to adapt the hardware to the application, if required; and not to provide more than is necessary.Application at FalconbridgeTo illustrate this approach, two examples of actual installations at the Sudbury Operations are presented, sulphuric acid loadout, and the Falconbridge Mine haulage system."

Jan 1, 1987

By R. V. Mrazek

The heat of formation of vanadium trichloride was determined at 298.15° K. Measurements were made in a solution calorimeter in which an aqueous hydrochloric acid-potassium dichromate solvent was employed. Data are presented for the heats of solution of vanadium trichloride and the vanadium trioxide "backup" compound, and for appropriate dilution reactions needed to preserve stoichiometry. The resulting heat of formation of vanadium trichioride (VCI3) at 298.15° K was found to be ?H°298.15° K = -138.89 ±0.37 kcal/g mole.

Jan 1, 1968

By F. G. Miller

[Petroleum tscknologists nnd progressive operatorr. constantly are striving to increase the percentage of oil thnt may be recorered from reservoir rocks through wells. The exhaustive studies that hve boen made of the function of natural gas in the production of oil, for example, havo aided operators greatly in increasing tho quantity of oil recovered from reservoirs. Natural gas dissolv.3d in and otheraiso asnociatod under pressuro with oil in rsservoir rocks, howovor, is not tho only source of energy available for rnovi~~ oil through sands to wells. In becomine Veservoi~enorgy conscious^^ encineera havo lonrned that in nnny petroleum resorroirs the edgewater flanking the oil accurrulation constitutos a potantinl source of enorgy cnpnblo, through pro1,sr control, of increasing oil-recovory officioncies materially. ?To longer is tho oncronchmont of mter into the oil- and gas-fillod uart of tho reservoir conridsred as evil to be combatted by dovious mothods but rnthar a nrtturrtl consequence, incident to the withdraval of oil nna gas from tho rolls, thnt mP.y be used nd~~mtngeoualy in lengthening the flowing life of wells ,md incre~sing the oconornic recovery nf oil and gns. Little is knom a3out tho nac&apos;n-~nisrn by mhich wnter qor-rtos in driving nil through reservoir rocks, nnd thjro is n scnrcity of published informa- tion on rates of rnovzrnant of ~ntcr +,hat will result in naxilnm oil recoveries. Bureau of Xine s er.gir.ess nr r&apos;reciate the ~aucity of scientific knowledge on the best methods of lying the natural rater drive to in- crease oil-recovery efficiencies arid ar9 initiating stildies that rill, they hope, contributo to tho procont small fund of information now available on the subject. This rh~.ort is s syr,o_nsis or brief c03pilation of published dAta and thought nccumulntod 30 far, groliminary to la-uorgtory ox~eriment+ tion NI& further resaarch on the principlgs und~rlying the nnturnl wnter drive RS it nffocts oil rocovory. The vrritors hopo th2t the omosition of available information prosentod in tho rey~ort rill stindate constructive thought and efforts loading torard moro comrlote extraction of oil and gas from resorvoirs.]

Jan 1, 1938

By D R. Peacor, J L. Mauk

Dioctahedral clay minerals in the volcanic-hosted Golden Cross epithermal Au deposit, New Zealand, have been investigated by petrography, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy/analytical electron microscopy (TEM/AEM) to determine the nature of these minerals in a hydrothermal ore deposit. Heterogeneity in the distribution of dioctahedral clays is observed from the hand-specimen scale to the TEM scale, indicating that primary rock textures and fluid pathways (related to rock type, porosity/permeability and fluid/rock ratios), in addition to temperature, are important factors controlling the distribution. As the proportion of illite in mixed-layer illite/smectite (I/S) decreases, TEM observations show decreasing layer stacking order, parallelism of packets, and packet size, and increasing apparent porosity. AEM structural data show a corresponding decrease in AlIV, AlVI, and K+, and an increase in Si, Ca2+, and Fetotal. The observations of this study indicate that local dioctahedral clay mineral reaction progress is controlled mainly by permeability and structure, but that this is superimposed on a predictable, system-wide clay mineral distribution that is controlled by temperature and fluid/rock ratio.

Jan 1, 1999

By P. Sanchez-Mejorada

GEOLOGISTS who are acquainted with the mines of northeastern Mexico realize that the most important lead-silver replacement deposits of the province are confined to a single formation. But since the formation is several hundred meters thick, the author has determined the relative position of the lead mantos in the belief that this information will prove useful in the search for new mines. This article describes the stratigraphic location of lead-silver replacement deposits known in several mines situated in a region comprising part of the states of Coahuila and Nuevo Leon. The area studied extends for 200 km* (125 miles) from east to west and 70 km (45 miles) north to south. Metallogenic Province: The most important metallic deposits of the region have the following common characteristics: 1) The orebodies occur as manto replacements of calcareous sediments. 2) The horizons that have contributed large tonnages of ore are in similar positions in the corresponding stratigraphic columns (as it will be shown later on). 3) Lead is the most important metal in the ores. Silver is commonly present in small amounts. Occurrence of zinc is dependent on the degree of oxidation of the primary sulfides. 4) A large proportion of the total production has been in the form of oxidized ores. 5) The deposits are located on anticlines. Rocks of Cretaceous age crop out over large areas of the states of Nuevo Leon and Coahuila. forming part of a belt that extends to the south along the eastern Sierra Madre. The sediments are cut by a small number of intrusive stocks ranging in characteristics from rhyolite to diorite. The most prominent structural feature of the region is a series of folds trending northwest-southeast. Faulting is not conspicuous in the region, although a major fault zone is found farther East.&apos; The physiography closely reflects structural features, with mountains formed by anticlines and valleys conforming with intermediate synclines. Narrow valleys have also been developed along the axes of many anticlines, where solution of limy sedi- ments and erosion have proceeded along axial tension fractures. Stratigraphy: Rocks of the Upper Cretaceous are exposed in only a small percentage of the total area. Generally they have been eroded away from the mountains and are covered by recent talus and alluvium in the valleys. Humphrey&apos; has published an excellent paper describing the Cretaceous formations of the Sierra de los Muertos, a short distance west of Monterrey. A brief summary of these formations is given below to convey an overall picture of the stratigraphic sequence that prevails just south of the area under consideration. Upper Cretaceous Indidura: Essentially thin shaly sediments. Cuesta del Cura: Limestone in thin wavy beds

Jan 1, 1959

By J. A. Finch

"Gas dispersion in flotation defines the efficiency of the process once the chemistry has been established. There are three measurements, superficial gas velocity, gas holdup, and bubble size, which along with the derived quantity bubble surface area flux, are used to define “gas dispersion.” Sensors for measuring gas dispersion in industrial machines have been developed. This communication describes the working principle of the techniques and illustrates their potential to detect problems and to improve the operation of individual cells, banks and circuits. IntroductionFlotation is the most widely used process to separate minerals and is finding increasing application in other chemical and environmental fields. The process exploits natural and induced hydrophobicity to collect selected particles on the surface of a bubble. Once the process chemistry to control hydrophobicity has been established, the efficiency depends on dispersion of air to generate the necessary bubble surface area. Bubble surface area flux, Sb, the interfacial area generated per unit time and unit area of the machine, is emerging as one of the most useful variables to quantify gas dispersion (Gorain et al., 1997, 1998) although not without its critics (Heiskenan et al., 2001).For a bubble population of mean size db at a superficial gas velocity (or rate) Jg, the bubble surface area flux can be derived from geometric considerations (Finch et al., 1999):"

Jan 1, 2002

By A He, J Li, J Pan, J Clout

The removal of sulfur from SO2 containing flue gas is improved by adsorbing SO2 into solution with manganese ions as catalyser, however, burnt lime slurry has to be added to modify solution pH and the CaSO3 by-product is of low economic value. In this paper a novel one step process for simultaneous manganese leaching-desulfurisation of flue gas is presented. An investigation of the effect of process parameters included flow rate and SO2 concentration in flue gas, adsorbing time, solution to solid mass ratio, leaching time, and their impact on the oxidation and removal of SO2 from flue gas. The catalysing mechanism of manganese ions on the oxidation and SO2 removal was demonstrated by calculation of the species originating from manganese ions and SO2 in the solution according to solution chemistry. SO2 removal in the adsorbing solution took place at pH 5 - 6, where manganese ions dominantly occurred as Mn2+, and the chain reactions for oxidation of SO2 starting from HSO3- were improved by the presence of Mn2+. SO2 bearing flue gas was effectively desulfurised by leaching rhodochrosite (MnCO3), with desulfurisation of the flue gas and modifying the solution pH being achieved simultaneously, and MnSO4 of high economic value recovered from the leachate. 85 per cent manganese leaching and over 70 per cent desulfurisation of the SO2-bearing flue gas were achieved with only one adsorption stage under optimum conditions.

Jan 1, 2004

By G-L. Wu, S-W. Wu

"The hot deformation behaviour of Nb-Ti microalloyed high-strength steel was investigated. Hot compression tests were conducted in the temperature range 900 to 1100°C under strain rates of 0.1, 1, and 5 s-1. Dynamic recrystallization (DRX) occurs as the main flow softening mechanism at high temperature and low strain rate. The hot deformation activation energy was calculated to be about 404 699 J/mol. The constitutive equation was developed to describe the relationship between peak stress, strain rate, and deformation temperature. The characteristics of DRX at different deformation conditions were extracted from the stressstrain curves using the work hardening parameter. The Cingara-McQueen equation was developed to predict the flow curves up to the peak strain. The processing maps were obtained on the basis of a dynamic materials model. The results predict an instability region in the temperature range 1010 to 1100°C when the strain rate exceeds 0.78 s-1. IntroductionThe 700 MPa grade HSLA steel is widely used in engineering machinery, automotive beams, carriages, and axle tubes, etc. (Pan et al., 2017 ). Generally, such grades contain a moderately high amount of Mn (approx. 1.4% and above), and microalloying elements like Nb, Ti, V, and Mo to impart the desired strength and toughness through solid-solution strengthening, precipitation hardening, and grain refinement dislocation strengthening (Chen and Yu, 2012; Opiela, 2014). However, the production costs can be greatly reduced by replacing part of the Nb, V, or Mo with inexpensive Ti and adopting the compact strip production CSP process (Opiela, 2014; Chen et al., 2015). Furthermore, the microalloying technology coupled with new-generation thermomechanical control processing (NG-TMCP) has proved efficient for achieving the proper balance between strength, toughness, ductility, and formability by means of a suitable combination of chemical composition and thermomechanical treatment parameters (Shukla et al., 2012; Wu, Zhou, and Liu, 2017).In hot forming processes, the complex microstructural evolutions are often induced by multiplicative hot deformation mechanisms, such as work hardening (WH), dynamic recovery (DRV), and dynamic recrystallization (DRX) (Zhang et al., 2014; Liang et al., 2015). Dynamic softening behaviour during hot processing has generated considerable interest because component properties are influenced significantly by its corresponding microstructural evolution (Wu et al., 2010). During deformation in the DRX process, deformed grains are replaced with substructures and newly formed fine and uniformly distributed grains. This occurs only when a critical strain for the onset of DRX is reached, and at the same time, the minimum rate of energy dissipating is reached (Ferdowsi et al., 2014). DRV occurs at a high strain rate and low temperature, reducing the stored energy greatly and making DRX difficult (Liang et al., 2015). The microstructural changes during DRX are sensitive to the processing parameters, such as strain rate, deformation temperature, and strain (Zhang et al., 2014; Ferdowsi et al., 2014). Therefore, in order to optimize the hot processing parameters, it is important to understand the behaviour of hot deformation visà- vis control of microstructural evolution."

May 1, 2019

By Dever Ashmead

FROM time to time metal-mine engineers have inquired why anthracite mines and their preparators are rarely operated on the two or three-shift basis. The subject may be approached as affecting: labor, development, the underground workers, the preparator, the outside workers, capital, the supply account, power consumption, the storage of coal over various shifts, railroad car supply, and the market. LABOR From the start, the adoption of a plan of three full-shift operations in a day would cause difficulty with the colliery employees, for they have never worked on that plan and would show their resentment by suspending work. Even if they could be induced to work according to this schedule they would not be as efficient, for they would be working more or less unwillingly at hours at which they are accustomed to rest. Operation on a three-shift basis would necessitate triple manning of each working place, and dissensions would arise between the men, for each shift would claim that the preceding shift had taken undue advantage and had not left as favorable conditions as it had found. To obviate these disputes it might be necessary to let out the work to a contractor, who would hire his helpers to mine out the chamber, or breast. The state mining law requires that a miner be put in charge of each working place. To conform with this provision he would have, to hire three helpers and two miners to mine the breast. The labor unions have been trying to abolish the subcontractor in mine work and any method of working that would cause his return, however innocent in purpose, would result in labor disturbances.

Jan 2, 1922

By James D. Bittner

Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. The environmentally friendly process can eliminate wet processing and required drying of the final material. The process requires little if any pre-treatment of the material other than grinding and operates at high capacity ? up to 45 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonnes of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the ST belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (500 µm) materials with very high throughputs. The triboelectric particle charging is effective for a wide range of materials and only requires particle ? particle contact. The small gap, high electric field, counter current flow, vigorous particle-particle agitation and self-cleaning action of the belt on the electrodes are the critical features of the ST separator. The high efficiency multi-stage separation through charging / recharging and internal recycle results in far superior separations and is effective on fine materials that cannot be separated at all by the conventional electrostatic techniques. Since 1995, this triboelectric process has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 100 machine-years of operation at locations in the US and Europe. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash.

Nov 1, 2011

By D. Gu

Shaft drilling is one of the most useful methods of driving shafts. This paper describes the application and development of the technique in coal mine construction in China.

Jan 1, 1993

By David G. Borg

Emulsions explosives, like slurries or water gels, are water based explosives. Emulsions were first introduced as a packaged blasting agent in the late sixties. Since then, many new variations have been developed, from small diameter detonator sensitive products to bulk loaded anfo/emulsion blends. Explosive detonation characteristics such as velocity of detonation, density/sensitivity relationship, strength, and water resistance along with how they relate to the type of rock and type of application will be presented. Various methods of sensitizing such as glass microspheres and chemical gassing along with product limitations and safety recommendations for bulk loading emulsions will also be presented.

Jan 1, 1994

By J. Jakumelt

The coupled simulation of mold filling and solidification for an investment casting process presents difficult. This is due to the complexity of the carious physical process and the geometry, To achieve this task in a precise way, the CFD program FLUENT and the casting simulation tool CASTS were closely coupled. Any physical quantity, such as velocities or temperatures, can be exchanged via files after each time step of the simulation. The communication and operating sequence of the programs is controlled by PERL-scripts. This enables the expertise of FLU ENT for flow simulation and the strength of CASTS, for casting simulation to be combined. The coupled simulation was successful applied to an aerospace investment casting. Several physical models were tested for correct treatment of the casting filters, the porosity of the mold and the viscosity of the liquid metal. The results demonstrate that even complex investment casting geometries can be investigated using CASTS-FLUENT.

Jan 1, 2003

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 25th August, 1976. Dr R. E. Robinson, (President) was in the chair, and declared the meeting open at 16h00. Obituaries The president: It is my sad duty to announce the death of the following members of the Institute : P. A. Creewell, Life Fellow; A. S. Davis, J. S. Hay, P. O. Large, N. McCaskell, and H. G. M. McKerrow, Life Members; C. L. Bererge, Fellow; T. Bulloch, G. Douglas, R. W. Forrester, and C. G. P. Sack, Members; P. R. Garcia, W. A. Naude, and J. P. Slager, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments&apos; silence. Minutes The President: May we confirm the minutes of the General Meeting held on March 17th, 1976, as published in the June issue of the Journal? Agreed. Welcome The President: It is my pleasant duty to welcome a number of guests and distinguished visitors this evening. First, I would like to welcome Mr R. Plumbridge, the President of the Chamber of Mines, and Mrs Plumbridge. We have had very close co-operation with the Chamber of Mines, and it is particularly gratifying that Mr Plumbridge has had time to be with us this evening in spite of very heavy engagements. Ook &apos;n spesiale woord van verwelkomirg aar mrr. N. Orsmord, die Staatsmyringerieur, en mev. Orsmord. Ors wil hierdie geleertheid gebruik om mrr. Orsmord geluk to wens met sy aarstellirg as die Staatsmyrirgerieur en die hoop uitspreek dat dit baie jare van samewerkirg met hierdie Irstituut sal beteker. We also welcome guests who, in one way or another, have been able to attend most of our Annual General Meetings, the Honourable I. B. Dillon, the Minister of Mines of Rhodesia, and Mrs Dillon. Once again we welcome them most heartily to our Annual Meeting. I would also like to welcome the representatives of many of our sister institutions : the Honorary Treasurer of the AS & TS, Mr D. G. Maxwell; the President of the South African Institution of Mechanical Engineers, Mr A. R. Adams; the Vice-President of the South African Institute of Electrical Engineers, Mr K. A. H. Adams, and Mrs Adams; the President of the Institute of Certificated Mechanical and Electrical Engineer s, Mr Martin and Mrs Martin; a member of the Executive of the South African Institute of Civil Engineers, Professor G. Bright ; the President of the South African Chemical Institute, Mr Vic Shuller, and Mrs Shuller; the President of the Institute of Welding, Professor F. P. A. Robinson, and Mrs Robinson; the President of SACPE, Mr M. R. Gericke ; the President of the Institution of Metallurgists, South African Branch, Mr D. R. Allen; the President of FSPE, Dr P. J. D. Lloyd, and Mrs Lloyd ; Mr A. J. H. Pole of the Association of Mine Managers, and Mrs Pole; and Mr M. D. Hoskin of the South African Institute of Foundrymen. A special word of welcome to Mr G. C. Young of our Orange Free State Branch, and Mrs Young ; and to Mr E. J. Jackson of our Witbank/Middelburg Branch. We have great pleasure in welcoming Dr F. M. Naude, the Scientific Adviser to the Prime Minister, and Dr W. C. J. van Rensburg, Technical Director of the Minerals Bureau. The latter is a new organization, and we hope their attendance here this afternoon forecasts a long period of co-operation between the Minerals Bureau and this Institute. Ook wil ek hartlik hier verwelkom die Rektor van Die Randse Afrikaanse Universiteit, professor G. van N. Viljoen. Ors het baie noue samewerking met die Universiteit gekry, en ek wil ook bier verwelkom die twee verteenwoordigers van die Geologiese-afdeling en die Chemie-afdeling, naamlik, dr C. Roering en professor G. W. Holzapfel. Last, but by no means least, a word of welcome to a very old friend, Mr Eric Boden, the Manager of AS & TS. To all our guests, a very hearty welcome to this our Annual General Meeting. Membership The President: It is required by our Constitution that I announce the names of a number of candidates who have been elected to various grades of membership. The list is a very long one, and I suggest that we simply record that these names will be published in the Journal. Any one who wishes to comment on these members should do so in writing to our Secretary. Agreed. Fellows: G. Paterson, P. H. Adler, F. W. G. Schoning, J. P. de Villiers, F. I. de Waal, J. R. H. Shaw. Members: C. J. Slavin, P. J. Perkins, R. J. I. Butler, A. M. Hattingh, C. E. Alvey, J. A. Engelbrecht, P. L. Gouws, J. P. Martin, J. F. Taylor, K. A. G. Blendulf, A. R. Gibb, W. E. Smith. Associate Members: D. R. Broderick, D. F. Cilliers, D. N. Stuart, P. Kraus, B. G. Pinder. Associates: D. E. Gibbon, D. F. Jacobs, R. F. W. Swanepoel, R. D. H. Bebb, H. H. Vernall, R. D. Gibson, J. P. van Wyk. Graduates : A. N. Morris, D. J. Payne, G. S. Worthington, A. S. Dennison, A. R. Godfrey, N. Holloway, W. J. Rankin, G. S. Lyndon, R. J. van Proctor, J. J. Versluis, G. M. Miller. Students: B. J. Rabie, G. D. Webber, W. L. Blair, I. D. Mathews, K. McVey, S. W. Beer, R. W. J. Bentley,

Jan 10, 1976

By Robert M. Matyas, P. E. Sperry, Robert J. Smith, A. A. Mathews

INTRODUCTION The first Dispute Review Board (DRB) was utilized on a tunnel project 20 years ago. Increasingly utilized on a wide range of construction projects, DRB&apos;s are becoming the norm on tunnel and underground projects. This paper summarizes the growth in this usage, uses observations and experience to establish that barriers to the utilization of DRB&apos;s are more perceived than real and that many arguments against the DRB concept are not valid, and notes some of the salient elements that should be considered in practice to optimize DRB effectiveness. The purpose of the paper is to provide an annotated checklist for current and prospective users. The basic concept, structure, and operation of DRB&apos;s are described elsewhere and will not be repeated here (ASCE, 1991). DISPUTE REVIEW BOARD USAGE A compilation of Dispute Review Board usage for tunnel and underground projects to January 1994 indicated use on 63 contracts with a cumulative construction value of $3.8 billion and a total of 60 disputes settled. As of that same date, DRB&apos;s were planned for another 63 contracts with an estimated construction value of $4.7 billion. (A listing of these 126 projects is available from the authors.) This success and popularity have spread to other civil projects as well as process and building construction. The increase in DRB usage has been exponential. See Figure 1.

Jan 1, 1995