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By C. Legote

"This paper investigates the conditions leading to the indefinite termination of production in four critical primary panels at an underground coal mining operation, the observed shortcomings in the mining approach, and the proposed strategy to mine through the affected panels. Initial assessment of the abandoned panel conditions indicated time-dependent strata failure,(i.e. bolted roof failure overrunning intersections), which occurred from mere minutes to up to four weeks post-production, with and without prior warning of failure. This prompted the constant re-supporting of back areas, which raised safety and productivity concerns. Investigation of the initial mining conditions revealed that the failures were due to a critical combination of factors, the chief of which was isolated horizontal stress. Other factors that were initially overlooked by the mine (i.e. influence of hydraulic stress, misinterpretation of borehole data), resulted in the conditions being described as abnormal. Remedial actions were determined, and in so doing, a new strategic approach was formulated to thoroughly address all failure concerns. The four panels were explicitly planned to serve as the main intake and return airways for the recently commissioned secondary ventilation shaft, as well as providing access to millions of tons in proven coal reserves. It is thus imperative to mine the panels. A feasibility study showed that the proposed strategy set for implementation would be financially viable. Paper written as project work carried out in partial fulfilment for BEng(Mining Engineering) degree"

Jan 1, 2015

By Alfred C. Lane

WE recently received from Professor A. C. Lane, Emeritus Professor of Geology and Mineralogy, Tufts College, Mass., and a Corresponding Member of this Institute, a very interesting account of some recent developments in radioactive methods of determining the age of minerals and, therefore, of the rocks in which they occur. It deals in particular with studies of the minerals of certain pegmatite dykes on the Huron claims and Bear claims in southeastern Manitoba, which, the results indicate, are among the oldest rocks of the earth's crust. The following article presents a non-mathematical summary of Professor Lane's paper . . It will be noted that he is anxious to obtain suitable samples of certain minerals and rocks for further age studies. We hope some o our members may be able to supply him with the material he needs. It may be well to explain briefly how the age determinations are made. Uranium is continually breaking down, or disintegrating in successive steps through radium, etc., to a final product which is lead (uranium-lead), and the rate at which this change takes place is known. Minerals containing uranium will therefore contain lead also, and the lead-uranium ratio mul-tiplied by a certain factor (approximately 7 ,600) will give the age of the mineral in millions of years. Thorium also disintegrates at a known rate to give lead (thorium-lead) as a final product, and the age of a mineral containing thorium can thus be calculated from the lead-thorium ratio. Thorium breaks down more slowly than uranium. In unit time, one gram of thorium produces about as much lead as 0.36 grams of uranium.-ED.

Jan 1, 1938

By Davis Baker

The direct-metal cars or ladles of the Maryland Steel Company have a capacity of 18 tons when filled within 12 inches of the top. On account of this large capacity, the formation of skulls in these ladles is by no means as rapid as in smaller ladles; but a skull once formed is a very unwieldy piece of metal to handle, and especially to remove from the ladle. We have found it cheaper to clean ladles often rather than make very heavy skulls. We aim to keep the ring of chilled metal that forms on the surface of the iron chipped off, so that the skull shall form principally at the bottom until it becomes so thick as to render the ladle unfit for service. Sometimes it happens that a ladle may be held for several hours filled with molten metal. This invariably leaves a large amount of chilled metal in the ladle. Frequently the skull will weigh several tons, and will be of the full size of the ladle inside, with a top crust, having perhaps a hole 12 inches square, through which the molten metal was poured. In order to remove skulls that cannot be easily chipped out with a bar, we use what may be called a skull-extractor, consisting of a hydraulic cylinder mounted in the center of a heavy cast-iron plate, standing vertically on a suitable foundation. Figs. 1 and 2 show the construction and operation of this apparatus, Fig. 1 being a view of the extractor with pistons extended to full stroke, and Fig. 2 a view with ladle in position and pistons about to commence the stroke. in both figures, A is the hydraulic cylinder, B the vertical cast-iron plate, and C the foundation. The water-pressure, admitted through the pipe, P, is 750 pounds per square inch, and the inside diameter of A is 14 inches. There are two pistons: D, fitting the bore of the cylinder, and E, 84 inches in diameter, moving inside of D. Both pistons move together when

Jan 1, 1893

By R. W. Raymond

(Pittsburg Meeting, March,1910.) THE Giroux Consolidated Mines Co. is equipping a five-compartment shaft at Kimberly, Nev., which will serve the Alpha mice. The depth of this shaft, January, 1910, is 963 ft., and of this depth 948 ft. was opened by raising, 15 ft. of sinking was done so that the bearers, collar-set, and three shaft-sets might be installed and concreted, and with this done it was possible to erect the necessary surface-equipment for resuming shaft-timbering on the completion of the raise. The arrangement of the shaft-timbering is shown in Fig. 1. At the 1,000-ft. level of the Alpha, and 750 ft. SW. from the Alpha shaft, a 14- by 18-ft. station was cut, and a 25-h-p. air-hoist *as installed. From here the raising commenced on July 5, 1909. The raise was cut approximately 13 by 21. ft. in area, and supported by timbering with square sets, illustrated in Fig. 2, which shows the division into four compartments. The end compartments, which were used as chutes, had the center girts heavier than in the others on account of the wear from falling rock. The chute-lining was braced by inserting 8- by 8-in. stiffeners parallel to and half way between successive caps. Similarly, the lagging on the wall sides of the cage-way and the compartment for pipes and ladder was stiffened with 4- by 6-in. timbers. In the pipe-and-ladder compartment the chute-stiffeners were reinforced with 8- by 8-in, struts, and as the cage-way was partitioned off by braced lining, there was practically no chance of rock entering the ladder-way in case a chute burst into the cage-way. Over the two center compartments the last two, sets were always bulkheaded with 8- by 12-in. timbers, shown in Fig. 3, and from the lower bulkhead the cage sheave-wheel was suspended. After a round of holes had been blasted and the loose

Jun 1, 1910

By Walter C. Lorenz

Samples of materials containing pyrite from various coal mines and coalbeds were studied to compare their compositions and oxidizing characteristics. Pyrite was the only form of iron sulfide identified, but X-ray diffraction, emission spectrography, and microscopic analyses revealed similar suites of minerals and trace elements. The pyrite occurred usually in spherical clusters of very small crystals. The oxidation of pyrite in solutions of PeSO4 and Fe2(SO4)3 and in the presence of an iron oxidizing bacterium Ferrobacillus ferrooxidans, was studied through a manometric technique. FeS04 or Fe2(SO4)3 solutions had no appreciable influence on pyrite oxidation under the test conditions, The bacterium acted as a catalyst, greatly increasing the oxidation rates; however, in three samples that also contained calcites, bacterial oxidation was greatly reduced. The oxidation rates also increased approximately as the percentage of pyrite in the samples increased. For the series of samples studied, there was no definite correlation of the results with the location of the various mines nor with the acidity of alkalinity of the mine drainage.

Jan 1, 1963

By Daniel E. Sullivan

This Bureau of Mines publication examines the potential impact on minerals of the tariff and nontariff agreements that resulted from the Tokyo Round of the Multilateral Trade Negotiations, which were conducted under the auspices of the General Agreement on Tariffs and Trade. These agreements will affect minerals by reducing tariff levels and by changing rules by which they are traded internationally.

Jan 1, 1981

By Lex L. Udy

Properties of an explosive which itiuence its performance on rock breakage are analyzed in relation to the rock: hardness and a discussion on the interaction of an explosive with the rock during the blasting process is given. Theoretical concepts regarding ideal and non-ideal detonation are reviewed to explain how the physical and chemical factors of an explosive influence the rate of energy release and its consequence on blasting performance. While a lower velocity of detonation indicates a slowed chemical reaction it does not necessarily mean a loss in energy from the explosive. High density ammonium nitrate (HDAN) can be used effectively in the formulation of modern industrial explosives to slow the energy release rate with its attendant decrease in detonation velocity. Examples of blasting performance using custom formulated explosives with HDAN are presented.

Jan 1, 1995

By R Berry

This paper looks at two ways to estimate the bulk mineralogy of the rocks for assay intervals. The aim is to find an efficient indicator of the most common minerals in the rock. Phase (modal) analysis has traditionally been done using visual methods such as point counting and image analysis. A modern version of this process is the X-ray point counting routine using the SEM-EDS based software. These methods are too slow and expensive for routine analysis of bulk sample mineralogy at the normal assay spacing.Two sources of data were considered that provide information that can be used to determine the mineral abundance in assay samples. The most widely applied method is (semi-) quantitative X-ray diffraction (QXRD). The QXRD method is most applicable to major minerals and has limited application to minerals at low abundance. The nominal detection limit is 0.5 per cent. Values below five per cent have large errors. A second, less common, method is calculation of mineralogy from chemical assay data. Conversion of chemical analyses to mineralogical analyses depends on the unique chemical composition of each mineral. Elements only found in one mineral are easily accounted for, but many compositions are ambiguous. Deciding on the actual mineralogy is not simple. Recalculation of mineral mode from chemical analyses is more accurate than QXRD when the correct minerals, and mineral compositions, are known.Where only a few QXRD analyses are available they can be used to setup a protocol for calculation of mineralogy from assay data. Linear programming works well in this environment. The best results are obtained when both H2O and CO2 are directly measured. Loss-on-ignition (LOI) should be included if these are not available.Where both QXRD and chemical analysis are available for all samples, the best results are obtained using the least squared method to merge the data sets assuming QXRD has much higher analytical errors than chemical assays. The combined method provides more robust results because the high abundance minerals are controlled by the QXRD measurements while the chemical assays improve the precision for low abundance minerals

Sep 5, 2011

By T. Majcherczyk

Shaft lining reinforcing analysis of two shafts under construction has been presented in this study. The first shaft was driven from the surface, while the second was deepened. Mining and geological conditions have been studied with respect to the lining capacity. The improvement of shaft stability comprised two elements, i.e. reinforcement of the shaft lining capacity and improvement of the strength properties of the rock mass. In both tested cases, the particular hazard was connected with non uniform loadings of the lining, which could generate shearing stresses within lining structure. Thus such elements as armored concrete with high strength properties, bolting and injection sealing of the rock mass, and the use of special ring reinforcing the shaft lining have been used in order to reinforce the shaft-rock mass system. Practical conclusions related with new technological solutions, allowing the rock mass and shaft lining reinforcement, have been included for the present study. Practical conclusions related with new technological solutions, allowing for rock mass and shaft lining reinforcement, have been also included to the present study.

Aug 1, 2013

By Matthew I. G

A new process for leaching zinc sulphide concentrates with gaseous mixtures of SO2 and O2 in aqueous solution is described.The reaction of SO2/O2 with Rosebery, Mt. Isa, Broken Hill and Elura zinc concentrates yields zinc and iron sulphates, elemental sulphur and some sulphuric acid. Rates of zinc extraction are controlled by a surface chemical reaction without apparent interference from the elemental sulphur layer for SO2 concentrations up to 9 per cent in the gas phase. Pyrite in concentrate exerts an activating effect, possibly through galvanic interaction with the sphalerite. Metal extractions are dependent on SO2 and O2 tenors of the gas, particle size, and the acidity and zinc content of the solution, but are independent of the ferric ion level. Extractions also reach maxima at about 85°C.Generation of acid may be prevented by conducting the reaction in the presence of ferrous iron and at acidities of 40 g/l or greater. Zinc and iron levels in Elura lead concentrate may be reduced by leaching with SO2/O2.

Jan 1, 1981

By S. Chung

Mining in highly stressed ground conditions has been an increasing challenge at the Brunswick mine. Over the past 30 years, two large regional pillars were established on the 1000 m Level to support the ground for safe extraction of the surrounding ore. The South Regional Pillar contains about 5 Mt of ore and the North Regional Pillar has about 3 Mt of ore. In the fall of 2000, mining activities were suspended following a series of ground movements around the South Regional Pillar along weak geological structures. After extensive geotechnical investigations, a decision was made to carry out a mass de-stress blast in the West Ore Zone (WOZ) to cut the principal stress across an area of 135 m along strike and 86 m high. At the end of July 2001, the WOZ mass blast was successfully initiated. Following this success, the mine decided to take a similar approach to de-stressing the North Regional Pillar (NRP). The final mass blast was taken in early February 2003. Advanced blasting technologies, including state-of-the-art electronic detonators and blast simulation, played an important role in achieving the successful blasts. The high precision of delay timing and long delay duration of the electronic detonators ensured accurate and reliable initiations of over 800 blastholes in the WOZ mass blast. Orica’s DMC_Blast (Distinct Motion Code) simulation code was used to study different blasting blocks for the desired timing in the initiation sequence. This paper describes the process of applying electronic detonators in complex blasts, and discusses how blast simulation results were interpreted to guide engineering design of the mass blasts.

Jan 1, 2005

By Robert M. Cox

Surface mining of coal in the South developed into a major industry during the 1960's. The economic significance of the industry is much greater than is readily apparent when one considers only the value of the coal mined. The abun-dant supply of relatively inexpensive steam coal for electric power generation that has been derived from the surface mines has provided the foundation for the industrial expansion that has occurred throughout the South. The region, in gen-eral, has enjoyed the benefits of plentiful low cost electric power. However, re-cent political decisions, at all levels of government, threaten to destroy or severely curtail the surface mining of coal and eliminate the economic advantages once enjoyed by the region. These political decisions are rapidly changing the basic rules of operation and fundamental economics of surface coal mining. Recent changes, resulting from the enactment of environmental and health and safety laws and various bureaucratic rules and regulations, have had a three-fold effect: 1) Greatly increased operating cost, 2) increased lead times for mine development, 3) limited potential reserve base for future mining. Also current legislative proposals are casting a shadow of uncertainty over the future of all coal mining operations that has created serious delays and in-creased cost for the expansion of the coal industry necessary to meet our project independence goals. Technology Surface mining is the safest and most economical way to produce raw materials from the earth's crust. It also affords a more healthier working environment for the individual miner. Surface coal mining now accounts for more than 60 percent of the annual coal production in the South. Surface mining of coal requires the removal of the overburden to expose the

Jan 1, 1977

By A. M. Gaudin, D. W. Fuerstenau

IN concentration of certain ores by soap flotation, prevention of quartz flotation is desired; the contrary is true in treatment of some oxide iron ores. Experimental study of the flotation of quartz goes back at least a quarter of a century.' Clean quartz does not float with fatty acids or soaps but does float when activated by one of many metallic salts. Control of pH is important. Broadly speaking the problem of quartz flotation has been approached from the empirical side, as was the related topic of flocculation or dispersion of quartz suspensions? Empirical studies indicated the existence of critical relationships between the additions of collector and activator. These additions were not stoichiometric for the formation of soaps of the activator cation. For example, Gaudin and Rizo-Patrona found optimum quartz flotation at pH 10.6 using barium activation and oleate collection when the molar ratio of oleate to barium was 1 to 1 instead of 2 to 1, as would be called for formation of Ba(OL),. Cooke and Digre" ' found that if calcium is the activator, a minimum quantity of that agent is required for effective flotation when the pH is 11.5. In other words, if the concentration of Na' exceeds 10 -2.5 mols per liter or if the concentration of H exceeds 10-11 mols per liter, the concentration of Ca++ in solution required for quartz activation is increased. This suggests that H+ is much more effective than Na+ on 10-2.5 quartz, perhaps in the ratio ofp or 108. Schuh- mann and Prakash6 studied anew the activation of quartz by barium, calcium, aluminum, and ferric iron. Salts of these metals are activators provided they are in stoichiometric excess over the collector used with them. Alkaline-earth salts are effective only in alkaline circuits. Important as they are in giving data on the effect of various agents on quartz, all these studies fail to give information on the detailed structure of the quartz-solution interface. A beginning in this direction was made by Gaudin and Chang,? who measured the adsorption of radioactively marked barium and laurate ions at quartz surfaces, and by Gaudin. Spedden, and Laxen,8 ho measured the adsorption of radioactively marked sodium at quartz surfaces. Work has also been done by Bell0 n measurement of the adsorption of sodium ion and chloride ion at quartz-solution interfaces. In all these experimental measurements of adsorption, the solid was centrifuged or filtered from the bulk of the liquor with which it had been associated; and the composition of the solid surface was ascertained by analysis, after allowance was made for the ionic composition of the liquor included with the centrifuged solids on the assumption that it is identical to the bulk liquid. Adsorption measurements give only the total amount of collector adsorbed at the quartz-solution interface; they give no indication of the distribution of these adsorbed ions at the interfacial layer. It is the ionic structure of the solid-solution interface and its importance to flotation that is the subject of this paper. The structure of this interfacial layer can be investigated by means of electrokinetic methods so that by combining electrokinetic studies with adsorption measurements, a more complete picture of the quartz surface may be obtained. The following studies were made to ascertain how electrolytes used in the soap flotation

Jan 1, 1956

By Danforth R. Hale

The pressure of military use of quartz resonators led to efforts to Grow high, grade quartz crystals in Germany and in Great Britain during 19)3-25, and was responsible for a series of U.S.A. Signal Corps contracts beginning in 1946 with the Clevite Corporation (as the former Brush Development Company), Bell Telephone Laboratories, Antich College, and others. The technique of growing crystals from the melt, such as KI, NaBr, was already commercially inuse Quartz could not be so grown, since its utility depends on the form stable below 573°C, and, even if it could be grown from an extraordinarily viscous melt, the higher form passing through this transition becomes twinned. Again, several crystals were being grown commercially from water solutions; quartz, however, is listed in the common literature as being insoluble in water. Fused quartz, or vitreous silica, was chosen as raw mater¬ial by the European experimenters because of its thermodynamically lesser stability than quartz, and various alkaline solutions were tried for the purpose of enhancing the solubility.

Jan 1, 1964

By L. C. IlsLey

So many subjects are covered in State mine-safety regulations that any attempt to compare different State laws in their entirety would be futile. On the other hand, if one selects a single phase or branch of safety work, such a comparison may prove profitable. The subject selected for study in this paper is limited to legislation or regulations dealing specifically with safeguarding (electric) motored equipment used in gassy mines. T When one reads glowing accounts of the safety activities being carried on here and there it is easy to believe that everything which is right and proper is being done to safeguard the mine.workers; but, when one takes time to look into the weakness of many State regulations, it is evident that there is still room for improvement. Undoubtedly it would have been much better for the safety of mines if electrical equipment had been introduced into mines 50 years earlier. If electricity had been in general use when the first mine regulations were pre- pared, those formulating the rules would have covered this hazard along with other hazards, but as electricity came in at a later period, safe mine legisla- tion regarding it has been woefully neglected. Today the United States in general is far behind most other coal-producing nations in the provision of adequate safety rules or laws for the installation and maintenance of electrical equipment and wiring. Returning to the subject of our study, approximately 30 of the 48 States mine coal. More than 20 of these States' produce coal in large quantities. How- ever, of the 30 States only four, 3 Pennsylvania, Utah, Washington, and West Virginia, have laws which specially call for the use of explosion-proof types

Jan 1, 1929

By Günter Huber, Bruno Mattle, Helmut Westermayr, Daniel Spöndlin, Max John, Nejad Ayaydin

PROJECT DESCRIPTION Alignment The Strenger Tunnel forms part of the S16 four-lane expressway between Landeckand Bludenz. The construction of this important East-West connection started in 1973with the Arlberg Road Tunnel as its key constituent. Beginning in 1992, solutions for the section between Pians and Flirsch were investigated. Efforts to conserve nature and to avoid potential avalanche and landslide areas led to a solution detouring the villages in the Stanz valley. The starting points were predetermind by the intersections at Pians in the East and at Flirsch in the West. As a result of the expected traffic load and the comparatively high gradient of 2.9%, both one-way, two-lane tubes were constructed at once. The north tube is 5.851 m long, the south tube 5.775 m, see Figure 1. Layout of Tunnel Cross-Section The tunnel cross-section was determined by 2 × 3.75 m wide, 4.70 m high roadways, two sidewalks and sufficient space for two fans above the clearance

Jan 1, 2005

COUNCIL AND STANDING COMMITTEES, 1974-1975 Office Bearers : Prof. R. P. Plewman (President), Dr R. E. Robinson and Dr M. D. G. Salamon (Vice Presidents), J. K. E. Douglas (Honorary Treasurer), and P. W. J. van Rensburg (Immediate Past President). Elected Members of Council: Dr M. G. Atmore, E. Collier, G. H. Grange, Dr P. R. Jochens, Dr D. I. Legge, D. G. Malan, C. T. Shaw, L. W. P. van den Bosch, D. A. Viljoen, H. M. Wells, P. A. von Wielligh. Branch Chairmen: B. T. Hosking (Witbank-Middelburg Branch), D. A. Smith (Orange Free State Branch). Past Presidents Serving on Council: R. J. Adamson, M. Barcza (until May 1975), H. Britten, H. E. Cross, Prof. J. de V. Lambrechts (until December 1974), R. C. J. Goode, Prof. D. D. Howat, Dr J. P. Hugo, D. M. Jamieson, D. G. Maxwell, Dr J. T. McIntyre, V. C. Robinson. Ten Council meetings were held during the year, with an average attendance of 19, and the standing and sub-committees held 74 meetings. COMMITTEE CHAIRMEN Membership, Dr M. D. G. Salamon; Technical Programme-Metallurgy, D. A. Viljoen; Technical Programme-Mining, G. H. Grange ; Vacation School-Metallurgy, Dr P. R. Jochens; Vacation School-Mining, Dr M. D. G. Salamon; Awards, Prof. R. P. Plewman; Excursions, Dr D. I. Legge; Constitution, Rules and Policy, P. W. J. van Rensburg and Prof. R. P. Plewman; Mines and Works, P. A. von Wielligh; Education, P. W. J. van Rensburg. REPRESENTATIVES ON OTHER BODIES Associated Scientific and Technical Societies Members: V. C. Robinson and Prof. R. P. Plewman. Alternates : Dr R. E. Robinson and Dr M. D. G. Salamon. Federation of Societies of Professional Engineers Members : J. K. E. Douglas and P. W. J. van Rensburg. Alternates : Prof. R. P. Plewman and G. H. Grange. South African Council for Professional Engineers Member : R. C. J. Goode. Alternate : G. H. Grange. Engineers' Liaison Committee (Pretoria) Member: Dr J. P. Hugo. Alternate: P. W. J. van Rensburg. MEMBERSHIP Thirteen Fellows, seventeen Members, eleven Graduates, three Associate Members, eighteen Associ¬ates, twenty-six Students, and one Company Affiliate were elected during the year. Nine Fellows, four Members, and three Associates were admitted to retired membership. Eight Fellows were elected to Honorary Life Membership. Three Members and one Graduate were transferred to Fellows, nine Graduates and two Students to Members, six Students to Graduates, one Student to Associate, and one Associate to Associate Member. Six Fellows, ten Members, three Associates, and one Student resigned. A statement of membership as at June 30th 1975 and the end of the previous year is shown in the following tabulation: 30th - 30th June, - June, 1974 - 1975 Honorary Life Fellows - 9 - 15 Honorary Fellows 8 - 8 Life Fellows 170 - 170 Fellows 544 - 536 Members 512 - 523 Associate Members 10 -15 Graduates 130 - 133 Associates 194 - 210 Students 173 -175 Company Affiliates 70 - 71 1 820 - 1 851 [ ] OBITUARIES Your Council records with deep regret the death during the year of the following members: M. Barcza, Honorary Life Fellow and Past President of the Institute; J. A. Boyd, F. E. Keep and J. H. Taylor, Life Fellows; I. D. B. Corner, C. O'G. Deane, R. E. Gilmour, A. C. Hofmeyr, M. W. Howell, T. J. Robin and F. C. Steinhobel, Fellows; J. J. Frankel, Member; T. J. Higgs, Associate. FINANCE The annual accounts, which follow this report, indicate that income again exceeded expenditure by a margin of R21 410 (last year R28 524). This year's income of R71 184 showed a further increase compared with last year's figure of R55 025. Costs, however, also in¬creased, and it is calculated that, excluding non-recurrent costs, the cost of running the Institute in¬creased by R6 654 from R25 501 to R33 155 for the current year. The main increases were involved in secretarial fees, stationery and print¬ing, and in publication of the Journal. All indications are that costs will continue to rise, and we have been advised that the A.S. & T.S. will be increasing their secretarial fees by 25 per cent in the year ahead to meet their rising costs. This year's surplus was derived entirely from the revenue from sales of publications (R13 644) and a surplus from the 1974 Winter School (RIO 654). There can be no certainty that revenue from these sources can be repeated each year. Our funds are in a satisfactory position because of these worth¬while activities, but the administrat¬ion of the Institute should not de¬pend on them. Council will accord¬ingly have to give consideration in the year ahead to an upward adjust¬ment of subscriptions to meet rising costs.

Jan 10, 1975

Your Council has pleasure in submitting its report for the year ended 30th June, 1969. COUNCIL The following served as Office Bearers during the year under review: Messrs. R. C. J. Goode (President), J. K. E. Douglas and V. C. Robinson (Vice-Presidents), P. Lambooy (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Members of Council: Messrs R. J. Adamson, M. Barcza, F. P. Bath, Or J. M. Bereza, Or W. Bleloch, Messrs H. Britten, H. E. Cross, A. R. C. Fowler, A. E. Gilfillan, G. W. Holl, Prof D. D. Howat, Or J. P. Hugo, Messrs C. J. Irving, D. M. Jamieson, J. G. Kirchner, Prof J. de V. Lambrechts, Mr C. E. Mavrocordatos, Or J. T. McIntyre, Mr J. A. Nixon, Prof R. P. Plewman, Messrs J. F. Reid, H. Simon, C. G. Sowry, W. T. Stobart and P. W. J. van Rensburg. Ten Council meetings were held during the year with an average attendance of eighteen. FINANCE The annual accounts, which are attached to this report, show an excess of expenditure over income of R2,124, compared with an excess of income over expenditure of R4,218 last year. There are a number of reasons for this substantial change. There was a loss on realization of investments compared with a substantial surplus in recent years. The publication of the Journal once again resulted in a large loss in spite of a generous subvention of R2,000 from the Department of Cultural Affairs and other assistance amounting to R750. The revenue from sales of publications was down considerably. This is a figure which fluctuates considerably from year to year. The secretarial fee was considerably higher than previously. Due to pressure of work it was necessary for the Secretary to relinquish his duties with the Institute of Land Surveyors and, therefore, for this Institute to assume the additional staff costs involved. Finally there was unusual expenditure on the 75th Anniversary celebrations. There was a pleasing increase in revenue from subscriptions, due to the steadily increasing membership, but this was quite inadequate to cover the substantial increases in expenditure and losses in revenue mentioned above. The changes that have been effected in the arrangements for the publication of the Journal have been mentioned elsewhere in this report. It is expected that these will bring about substantial financial benefits in the long term. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of Rl00 and the total fund was therefore increased by this amount to R4,206. The balance sheet indicates that the market value of quoted shares and debentures increased during the year from R8,755 to R13,059, while the Accumulated Funds now amount to R22,567 as against R24,691 last year. MEMBERSHIP Fifty-six Members, fifty-five Associate Members, thirteen Graduates, twenty-two Affiliates and twenty- nine Students were elected during the year. Twelve Members were admitted to Life Membership; seven Associate Members were transferred to the grade of Member; four Graduates and two Students were transferred to the grade of Associate Member; five Students were transferred to the grade of Graduate; three Affiliates were transferred to the grade of Member; five Affiliates were transferred to the grade of Associate Member. Three Members, seven Associate Members, two Graduates, two Affiliates and six Students were removed from the Membership Roll in terms of By-Law 7.7.1. Your Council records with deep regret the death during the year of the following members: E. F. J. Bulman (Member), E. F. Chapin (Member), R. A. H. Flugge-de-Smidt (Hon. Life Member), T. S. Haldane (Member), J. M. Massie (Associate Member), S. W. Page (Student), S. R. Rabson (Member), M. Ramsay (Member), F. Wartenweiler (Hon. Life Member). A comparative statement of the membership as at 30th June, 1969, and the end of the previous year is shown in the following tabulation: 30th June 30th June 1968 1968 Honorary Life Members 12 10 Honorary Members 6 6 Life Members 176 189 Members 488 514 Associate Members 409 448 Graduates 60 68 Affiliates153 155 Students152 162 1,456 1,552 PAPERS AND JOURNAL The Institute is changing the format of the Journal from the present size to the standard international A4 size with effect from August, 1969. In making this change it will conform to more general practice today in regard to publications and this should effect certain economies and facilitate selling of advertising space. It has been arranged that in future the publication of the Journal, including advertisement sales, will be handled by Kelvin Publications (Pty.) Ltd. who are already doing this work satisfactorily for the Mechanical and Electrical Engineering Institutes. In making these changes the opportunity was taken of redesigning the outer cover of the Journal to incorporate the new coat of arms. The Presidential Address by Mr R. C. J. Goode and twelve papers which were published in the Journal during the year are listed below: August, 1968: Presidential Address: "The Institute-In retrospect and prospect." September, 1968: "Rotary mill liner practice in the South African gold mining industry," by J. H. French and O. E. Lissner.

By Daniel Hodouin, Claude Bazin, René del Villar

"A traditional linkage has long been established at Laval University's Department of Mining & Metallurgy between the Mineral Process (MP) and the Mining Exploitation (Min) on one hand, and between the Extractive Metallurgy (EM) and the Materials Engineering (Mat) on the other. This academic separation of Mineral Processing from Extractive Metallurgy at the educational level has become increasingly at odds with today's industrial practice in which both disciplines are not only complementary but also often intertwined. For instance, in gold ore processing, comminution, flotation, and gravity separation units are interfaced with atmospheric or pressure leaching modules and with carbon adsorption and electrowinning units. The new copper plants in South America combine comminution and flotation circuits with heap leaching, solvent extraction and electrowinning processes.In order to reflect this new industrial reality and to harmonise the options offered in both its engineering programs, the Department of Mining and Metallurgy of Laval University has introduced major changes in its curriculum in 1996. These changes reflect also the recognition that the somewhat secondary status given so far to Mineral Processing and to Extractive Metallurgy within their ""mother"" programs, Mining/Mineral Engineering and Materials metallurgical Engineering respectively, was in sharp contrast with their actual significance for the Canadian economy. Leading industrial voices have raised similar concerns and the Canadian Engineering Accreditation Board has also addressed this problem in its latest program evaluation.The changes implemented at Laval aimed at a) better representing MP and EM within the two undergraduate programs; b) training top-level versatile and multidisciplinary engineers, fluent in all aspects of MP and EM, irrespectively of which of the two ((mother)) programs they had chosen and capable of meeting today's industrial requirements; c) training students in process analysis, optimisation and automatic control using state-of-the-art software, and d) taking into account the co-operative nature of both undergraduate programs.Results are very encouraging in terms of student enrolment and industrial response. However, some concern is expressed on the sustainability of the renewed curriculum considering the drastic budget restrictions in effect at Laval as in most other Canadian universities."

Jan 1, 1999

By J. A. Kromhout, J. Trouw, A. A. Kamperman, M. Kick

Mould powders play an important role in the stability of the continuous casting process. The main functions of mould powders are to provide sufficient lubrication and to control the horizontal heat transfer. Because process control of thin slab casting is more stringent, it is generally assumed that mould powder properties become more critical as well. In 2000, the Direct Sheet Plant at Corus IJmuiden (DSP) was commissioned, incorporating a thin slab caster designed for casting speeds up to 6 m/min. During commissioning, several operational problems with mould powders were encountered i.e. insufficient liquid pool depth and the formation of rims/lumps. To investigate the operational mould powder problems, some of the mould powders were characterized using physical and mineralogical methods. The results were linked to operational experiences. It was concluded that for thin slab casting, a stable slag formation is obtained with a proper choice of free carbon and an even distribution of the carbon particles within the granules. The physical properties of mould powders are not as critical as expected when the additional mineralogical requirements are taken into account. Keywords: mould powder, characterization methods, thin slab casting.

Jan 1, 2004