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Coal mining in the Illawarra commenced in 1848. By the early twentieth century mining operations were spread over quite a distance along the coast centred on Wollongong. By this time there were already numerous tunnel mines and one shaft mine. Coal was first reported in Illawarra by Lieutenant Flinders on a voyage of exploration, southerly along the coast from Sydney in 1796. Because of the topography, particularly the escarpment and the narrowness of the coastal plain, access from Sydney was not easy by land and the normal access was by sea. It was not until some coastal areas had been developed for agricultural purposes that the mining of the seams on the South Coast commenced for the supp- ly of fuel. The most important mines in the early nineteenth century were Bulli and Osborne Wallsend. In general, coal was won from the tunnel mines and was transported directly, usually by tramway, to the nearest shipping point. Considerable hardship attended the earliest attempts at mining coal in regard to materials for mining and the way of life of the miners in the vicinity of the mines. With the growth of production and the installation of coke ovens at some mines the area, hitherto virgin bush- land, began to take on a more industrialised appearance. The mines were necessarily small,

Jan 1, 1976

NEW YORK LOCAL SECTION Executive Committee L. W. FRANCIS, Chairman WILLARD S. MORSE, Vice-Chairman THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y J P. A. MOSMAN, Treasurer Louis D. HUNTOON Since the annual meeting in February, the New York Section of the Institute has held three meetings. The meeting-on March 10 was held in conjunction with the American Society of Mechanical-Engineers and the American Electrochemical Society, at the Engineering Societies Building. The papers of the evening were devoted to records of progress in the Processes for the Photographic Reproduction of Natural Colors. The speakers of the evening were F. E. Ives, one of the earlier workers in color photography, Westley Allison, C. W. Robinson, George F. Clyfton, John B. Taylor, and Henry Hess. The April meeting was held on April 22 at the Institute headquarters, and the topic for discussion was Sanitation in Mining and Metallurgical Work. The principal paper was by J. W.. Luther, chief surgeon of the New Jersey Zinc Co. This was followed by a similar paper by Charles L. Close, secretary of the Welfare and Sanitation Committee of the United States Steel Corporation, and by an account of the sanitation work done in Cuba by the Spanish-American Iron Co., which was read by the Chairman, in the absence of Charles F. Rand. Following these papers general discussion was indulged in.

Jan 6, 1914

By L. A. Beckett

Load-Haul-Dump machines (LHDs) have contributed significantly to high productivity in hard-rock mining in recent years and are now being introduced into the coal mining industry (Rao, Haycocks and Lucas, 1975; Mining Magazine, 1975). The superiority of the LHD when compared to loader-plus- shuttle-cars has been demonstrated for several operations (Rao et al., 1975), and the number of manufacturers now in the coal mining LHD market (Mining Magazine, 1975) indicates that the concept will be of considerable future importance in the U.S. coal industry. Currently more than 90 percent of U.S. underground coal production is obtained by room-and-pillar methods (Coal Age, 1976). This system presents certain complexities with regard to haulage analysis; among these are constriction of travel routes, variation of haulage distances as different faces are worked, and change in the overall physical layout as mining progresses. Furthermore, current experiments in the use of more than one continuous miner in a section (Mining Magazine, 1975; Coal Age, 1976) suggest the possibility of highly intensive mining operations, with loading proceeding from more than one point simultaneously, in which the overall patterns for machine movements must be carefully arranged to minimize delays.

Jan 1, 1979

By Thomas V. Falkie, R. Venkataramani

The empirical nature of this investigation required measurements of variables under operating conditions in underground coal mines. The variables to be measured were based on the postulated character¬istics of the loading function, as described in the previous chapter. One class of variables presumed to influence the loading function are geological variables. Accordingly, the sites for data collection were selected in different bituminous coal seams at dispersed locations in order that variation in geological conditions would exist. Seven mines in central and western Pennsylvania and one mine in northern West Virginia were selected as data collection sites. Five different coal seams were represented by these mines. The remaining classes of variables - geometric, mechanical, and procedural - were measured as they occurred in the mines. A description of the measurements, and the conversion of these measurements to forms which could be-analyzed for effect on the loading function is given. Mining Dimensions At the underground working face, the following dimensions were measured: a. Thickness of coal excavated. b. Thickness of shale excavated. c. Total height excavated. d. Width excavated. e. Depth of penetration of each machine cut. With the exception of the last of these dimensions, all were measured

Jan 1, 1972

By J. Weertman

High-temperature creep experiments were carried out on indium, lead, and on binary substitutional alloys of In-Pb, In-Sn, In-TI, In-Cd, In-Hg, Pb-Bi, Pb-Sn, Pb-In, and Pb-Cd. The stress at which the power law creep equution breaks down was found to be much smaller for indium and lead than for metals with larger elastic moduli. The exponent over the stress in the power law creep equation was found to decrease upon alloying from values close to 4.5 to values near 3. THIS paper describes a set of high-temperature creep experiments made on high-purity lead and indium and on lead-rich and indium-rich single-phase binary alloys of various metals. These ex- periments were carried out to check two predictions of some creep equations derived by us"2 from a dislocation creep model due essentially to Mott. This model is shown in Fig. 1. Here dislocation loops are emitted from sources, not shown, situated on different slip planes. As the loops expand they come into each others' stress fields and are stopped. However, at high temperatures, as Mott has pointed out.

Jan 1, 1961

By Richard E. Gray, Robert W. Bruhn

INTRODUCTION Underground coal mining has been practiced in the United States for over 200 years. Much early mining was not as efficient as today and unrecovered coal pillars, often of variable size and spacing, remain to support the overlying strata after mining has ceased. These conditions constitute a potential subsidence problem since the pillars will eventually fail. The possibility of subsidence above an abandoned mine must be anticipated except when total extraction has been achieved, permitting subsidence concurrent with mining, or when large coal pillars which have an adequate factor of safety for long-term support remain in the mine. Coal is found in 37 states and is mined under- ground in 22 states (HRB Singer, Inc. 1980). Underground mining produced 40 percent of the 7.5 x 10" kg. (830,000,000 tons) of U. S. coal mined in 1980 (Keystone, 1981). There are approximately 70,000 abandoned or inactive underground coal mines in the United States and approximately 2000 active underground coal mines (NAS/NAE, 1975). Underground coal mining in the United States will eventually extend beneath 162 x 109m2 (40 million acres). Thirty-two billion m2 (8 million acres) are already undermined (HRB Singer, 1977). Subsidence due to mining has affected more than 8 x 109m2 (2 million acres) in 30 states, 7.7 x 10 9m2 (1.9 million acres) from bituminous coal mining and the remainder primarily from anthracite mining (Johnson and Hiller, 1979). Subsidence from all other underground mines has affected only 6.9 x 10 7m2 (17,000 acres) (Johnson and Miller, 1979). Subsidence appears to be particularly widespread in two states, Pennsylvania and Illinois, although serious subsidence is found in localized areas of numerous other states (HRB- Singer, Inc. 1977). Host underground coal mining has occurred in the eastern United States, where the U. S. Bureau of Mines estimates 1.6 x 109m2 (398,600 acres) in urban areas in 18 states (out of a total 1.7 x 109m2 1418,400 acres]) are threatened by subsidence (Table 1) (Johnson and Miller, 1979). Pennsylvania and West Virginia contain 57 percent of the total threatened areas. The U.S. Bureau of Mines estimates the total cost to stabilize the estimated 1.7 x lo9m2 (418,400 acres) of subsidence prone urban land located above abandoned mines is over $12.5 billion (1978 costs).

Jan 1, 1982

H. W. Glen (ed.). Proceedings of Asbestos Symposium, Johannesburg, South, Africa, 3rd-7th, October, 1977. Randburg, National Institute for Metallurgy, 1978. 158 pp. (Copies obtainable from the Department of Mines, P.O. Box 4584, Johannesburg, 2000 South Africa.) This Symposium, which concentrated on the theme of dose-response relationships for asbestos-related diseases, was attended by an internationally representative group of experts in this field. Bulk solids The Powder Advisory Centre announces its third annual International Conference on Bulk Solids Swrage, Handling and Flow, to be held at the Holiday Inn, Liverpool, on 7th to 9th November, 1978. This sequel to the extremely successful November '76 Stratford and November '77 Nottingham Conferences is again to be co-sponsored by a number of internationally acknowledged professional societies, including the Institute of Materials Handling (through its Bulk Solids Panel), the Institution of Production Engineers, and the American Society of Mechanical Engineers (through its Materials Handling Engineering Division). NIM reports Report no. 1943 A review of the literature on the separation and determination of rare-earth elements. (23rd Mar., 1978.) Report no. 1947 The cation- and anion-exchange behaviour of various base-metal chlorides in polar organic solvents. (lOth Mar., 1978.) Report no. 1948 The measurement of trace amounts of gold in solution by atomic-absorption spectrophotometry and carbon-rod atomization. (28th Feb., 1978.) Report no. 1949 The kinetics of the leaching of zinc sulphide concentrates in acidic solutions containing ferric sulphate. (23rd Mar., 1978.) Report no. 1950 Factors affecting the carbon contents of alloys formed during the prereduction of chromite ores. (31st Mar., 1978.) Report no. 1952 The effect of slag composition on copper losses to silicasaturated iron silicate slags. (31st Mar., 1978.) Report no. 1953 A fundamental investigation into the depression of copper-activated sphalerite. (28th Apr., 1978.) Report no. 1956 An improved ion-exchange separation of rare-earth elements for spectrographic analysis. (10th Mar., 1978.) Report no. 1960 The recovery of ferrochromium from furnace slags and related products. (20th Aug., 1976; declassified 31st Mar., 1978.) Process instrumentation The National Institute for Metallurgy and the South African Institute of Measurement and Control are organizing a symposium that will draw the attention of researchers and industrial workers to the importance of metallurgical process instrumentation.

Jan 1, 1978

By C. F. Smart

SINCE their comparatively recent development, the alloys of cadmium with silver and copper or nickel, and of cadmium with nickel alone, have been used somewhat extensively as liners for connecting rod bearings and main bearings of internal-combustion engines. In applications where, owing to high hearing loads and elevated operating temperatures, the life of hearings made from tin-hale or lead-base alloys has been undesirably short, cadmium alloys have demonstrated considerable advantage. In applications where, because of deflection of the crankshaft or bearing supports, copper-lead bearing metals have resulted in scored shafts, cadmium alloys have been operated successfully. The somewhat serious drawback to these alloys in hearing service has been that they, in common with copper-lead and certain lead alloys, are susceptible to corrosion in the presence of lubricants containing organic acids. These acids may be fatty acids (such as oleic acid) derived from animal or vegetable oils that sometimes have been compounded with engine lubricants, or they may be compounds of an acid nature developed by the oxidation of some petroleum oils under operating conditions. The result of such acid attack on hearings is illustrated by the photograph, Fig. 1. The petroleum oils that are most readily oxidized to a corrosive condition, and the operating conditions under which such oxidation most readily occurs, are now rather well known among the technical organizations of both the petroleum and automotive industries. While means have been developed for inhibiting petroleum oils against such acid formation, the knowledge that this condition may be encountered has been a factor in restricting the wider use of cadmium alloys as engine bearings. It has appeared, therefore, that their value and use would be enhanced if they could be made corrosion-resistant to a degree compatible with the most severe operating requirements. Investigation, undertaken with this in view, indicated that the addition of fractional percentages of the metal indium to the cadmium bearing

Jan 1, 1938

By N. Langsford

The Archaean Yilgam craton has been a major gold province since 1888 with production and reserves of about 4700 tonnes. Production in 1994 was about 135 tonnes. The largest deposit, the famous Kalgoorlie Golden Mile, contains about 2000 tonnes of gold. About 40 deposits containing more than 35 tonnes (1Moz) of gold has been discovered so far in the Yilgarn. Most of the craton has deep weathering profiles inherited from previous tropical climatic conditions, modified by subsequent arid conditions. A mantle of transported material covers much of the variably stripped weathering profiles. Resolving the geology of the volcanic-sedimentary units (greenstones) and the structures that host the gold mineralization relies heavily on aeromagnetics and shallow drilling.

Jan 1, 1995

By William H. Kobbé

The word recovery as used in this paper is applied in its broader sense and not limited to wells producing from horizons of unconsolidated sands. Certain problems connected with the winning of petroleum from such horizons present themselves while drilling is in progress and should be considered before drilling is commenced wherever unconsolidated sands are expected. Maximum recovery depends not alone. upon efficient pumping methods but also upon the selection of a proper drilling system and the completion of a well especially adapted to the extraction of these oil-bearing sands. 11. DRILLING Determining Factors in Selection of Method The selection of a drilling method for the development of a region in which the oil reservoir consists of unconsolidated sands is based on the following considerations: (1) Character of the formations overlying the reservoir; (2) thickness of the oil-bearing stratum or strata; (3) thickness and character of water or gas sands; (4) gas pressure to be encountered or expected; (5) total depth of well. 1. Character of the Formations Overlying the Reservoir The strata overlying the reservoir may consist of beds of shales, clays, sands and other soft materials, or they may be slates, limestones and sandstones consolidated to all degrees of hardness. Very often the overlying strata are predominantly of soft materials but interbedded with harder formations. Likewise, soft strata are encountered at different horizons in an overburden consisting almost entirely of the harder sedimentaries. The physical character of this overburden is frequently

Jan 1, 1917

I have chosen this topic for my address with the intention of preserving a rather extraordinary record of recurrent additions of capital in the financing of one of the world's important silver-lead-zinc mines. The recitation of the trials and tribulations which fore-shadowed the rise of Mount Isa Mines to a position of relative prominence in the realm of non-ferrous mineral production may, I hope, be of assistance to some of the younger members of the Institute who may be called upon during their careers to meet similardevelopmental and financial problems.Mount Isa Mines Limited was incorporated in New South Wales in 1924 with an Authorised Capital of 40,000 shares of £20 each.In November 1925 the Company acquired the leases and water rights of the Mount Isa Proprietary Silver-Lead Limited for 6,250 fully paid £20 shares. Shortly thereafter, but in the same year, the £20 shares were split up into £1 shares, thus bringing the Authorised Capital to £800,000.The leases purchased consolidated and brought under one management the principal ore bodies of the Mount Isa area.Transportation facilities were indispensable to the economic future of the field, so the construction of a railway extending the Government line from Duchess, 54 ,miles to Mo.unt Isa, was assured by the passage of a bill in October 1925 by the Queensland Parliament. Under the provisions of the so-called Mount Isa Railway Act the Company was required to idemnify the Government against national loss on this branch line for a period of 10 years.

Jan 1, 1953

1. Book reviews Nonparametric geostatistics, by S. Henley. London, Applied Science Publishers, 1981. xiv + 145 pp. Reviewer: Douglas M. Hawkins Mineral deposits and global tectonic settings, by A. H. G. Mitchell and M. S. Garison. London, Academic Press, Geology Series, 198!. Reviewer: J. Lurie The mining and mineral laws of South Africa, by B. L. S. Franklin and M. Kaplan. Durban, Butterworths, 1982. Cloth, 240 X 150 mm, Lxxcii + 853 pp. R197,50 + GST. Reviewer: M. J. Martinson Aluminium- Volume II, by M. H. Govett and J. Larsen. Sydney, Australian Mineral Economics (Pty) Ltd, 1982. Reviewer: D. G. Maxwell International technology for the nonferrous smelting industry, by Noyes Data Corporation. Reviewer: D. A. Viljoen 2. New publications Coaltransport- an analysis of technical and economic factors, by Dag Pike. London, Financial Times, 1982. £86 (D.K.), D.S. $175 (overseas including first class airmail postage). Small solute concentration differences determined by interferometry, by H.E.L.G. Schweigart. Pretoria, CERG-CSIR (P.O. Box 395, Pretoria), 1982. 3. Mintek reports Report M8A determination, using solid zirconia electrolytes, of the activities of chromium oxide in ferrochromium alloys and slags at 1650°C. Report M31Software for the design of multivariable control systems by use of the Inverse Nyquist Array. Report M37A literature survey of the metallurgical aspects of minerals in Witwatersrand gold ores.This survey reviews the information in the literature Report M 39 The use of masking agents in the determination, by hydride generation and atomicabsorption spectrophotometry, of arsenic, antimony, selenium, tellurium, and bismuth in the presence of noble metals. Report M40 The use of X -ray-fluorescence spectrometry in the determination of uranium, cobalt, and sulphur in materials from mine dumps. Report M44 A n on-line dilution system for spectrometry ustng an inductively coupled plasma source. Report M47 The separation of trace elements from iron, and the analysis of iron-rock ores for use as reference materials. Report M49 A programme in BASIC for the appending of computer files. Australian coal The editors of World Coal and World Mining have announced plans to sponsor the IVth International Coal Exploration Symposium. The symposium will be held in Sydney (Australia) from 15th to 19th May, 1983. Small mine economics The editors of World Mining and World Coal have announced plans to sponsor the Second International Symposium on Small Mine Economics and Expansion in Helsinki, Finland, from 12th to 16th June, 1983. The first symposium was held in Taxco, Mexico, in May 1981.

Jan 1, 1982

By Carl E. Swartz

The Joint Session on Continuous Casting, of the Institute of Metals Division and the Iron and Steel Division of the American Institute of Mining and Metallurgical Engineers, convened in the Jade Room of the Hotel Waldorf-Astoria, New York City, on Feb. 23, 1944, at 9:15 o'clock, Carl E. Swartz presiding. C. E. SWartz.—It is gratifying to see so many out at what may seem an early hour for the beginning of A.I.M.E. sessions, but I think this number-—some fifty or sixty of you —is an adequate expression of the interest in these processes all over the United States, and possibly in foreign countries. I would like to ask those who feel that this type of program is of value to you to write or speak to some one of the Institute of Metals Division officers and suggest other topics for symposiums. We have a feeling that some of these current practices are of interest and we believe that under proper sponsorship many of the companies mill be willing to give publicity to processes such as those that will be discussed today. Also, we would like suggestions and criticisms, so that the next ones can be better. The subject of continuous casting is not new, of course. The two papers on the program this morning will adequately cover the history and some of the earlier processes, some of the theory and some of the practice, some of the reasons why these various methods did not work. I was rather interested in discovering, when thumbing through one of the A.I.M.E. publications tile other night, an article on continuous casting. I was not aware that the A.I.M.E. had published any papers on continuous casting, but there may be a number. The one that I happened to find was published in the 1915 volume, on the Mellen rod-casting process, and so we might say this is not the first session in which these subjects have been under discussion. However, there have been many improvements since then in all fields of metallurgical and mechanical engineering; consequently, I think that the papers today will be a little more involved and a little more complete in their technique. The first paper today will be given by one of our gentlemen of the press, who has done one of the outstanding jobs in this country in calling to our attention some of the newer processes that are being considered and being used in the metallurgical indus-

Jan 1, 1945

By Paul M. Tyler

Mineral raw materials, because they are essential to our industrial prosperity and military strength, must be made available in substantial quantities. regardless of cost. Variations in the cost of procuring minerals, as compared with the cost of obtaining other commodities, and changes in the cost of production of different minerals relative to one another, will naturally influence the quantities of a given mineral item that can be marketed readily. However, in the last analysis, the cost of winning minerals from the ground usually constitutes only a small fraction of the value of the end-use products and services derived from them. The miner's share of the cost of a typewriter, telephone circuit, or even a modem office building, is almost insignificant. Far more important to the ultimate consumer, therefore, than any minor saving in cost is the assurance of ample supplies of the minerals needed to aliment our expanding economy. To create a successful metal mining operation involves ( 1 ) the discovery and systematic development of a mineral deposit, (2) extraction of the ore, (3) the mechanical and metallurgical processing to eliminate worth- less or harmful impurities, and (4) the profitable disposal of the product. The first step of the technological process belongs chiefly in the realm of the geologist, the second is a mining engineer's job, the third is mainly up to the millmen and extractive metallurgists; whereas the fourth and equally important step poses a commercial problem that has aspects in common with the marketing of other products. Ore finding is far from being an exact science. There is no mathematical criterion for evaluating the efficiency of prospecting and exploration. Lady Luck shares the honors or assumes part of the blame along with the prospector and geologist. Marketing like- wise involves factors that seemingly defy engineering analysis. Although the other steps can be measured with some degree of mathematical accuracy, even they tend to vary so widely in basic principle, as well as in

Jan 1, 1959

By Alan Morris

IN a previous paper1 the results of cutting tests on free-cutting brass rod were reported. Investigation was made of the effects of variation in lead content, microstructure and cold drawing. The author's reply to the discussion of that paper includes a study of the directional cutting properties of drawn and annealed rod. The present paper records the results of tests made on series of samples in which the tin, iron and copper contents have been varied. The apparatus, used and method of testing are described in detail in the previous paper. The machine is of the pendulum-operated milling type used and described by Airey and Oxford.2 Angular readings of the height to which the pendulum rises after falling from a fixed position, both when a cut is made and when the pendulum swings freely, give the basis for calculation of the energy consumed in making a cut. Careful weighing of the sample before and after cutting gives a measure of the amount of metal removed. The results are expressed in foot-pounds per cubic inch of metal removed, and have been called "unit cutting energy." In the course of the discussion of the author's earlier paper, W. B. Price reported large-scale tests involving some 50,000 lb. of material. These tests indicated that the addition of as much as 0.6 per cent of iron and 0.25 per cent of tin had apparently no adverse effect on the high-speed cutting characteristics of the rod. The rod also contained a small amount of nickel. The test results reported here tend to confirm his observations.

Jan 1, 1933

By A. A. Burgoyne

"The McDame chrysotile asbestos deposit located near Cassiar in northern British Columbia isfound at depth and on trend to the southeast of the currently mined open-pit Cassiar asbestos deposit. The ultramafic rock hosting the McDame is serpentinized peridotite of the Upper Paleozoic Sylvester Group contained in an ophiolitic sequence preserved within a lower thrust sheet of the Sylvester Allochthon. The Sylvester stratigraphic package is a series of thrust slices composed of argillite, tuff and volcanic flows, diorite and serpentinite. Contacts between units are often fault-controlled.The McDame asbestos-bearing ultramafite is considered to represent a separate interleaved fault-bounded slice of rock distinct from the Cassiar asbestos deposit.Asbestos mineralization of the McDame deposit was discovered in /978. Exploration during /980 and /98/ focused on extensive underground drilling of the deposit and in /983 on geological mapping, airborne and ground magnetic surveys. In /984 a 622.5 m borehole was drilled with a 242 m intersection of McDame ultramafite of which the lower 15/ metres contain potentially economic chrysotile asbestos. The McDame deposit averages 90 m thick, trends north-south, dips easterly and plunges southeasterly. The deposit is estimated to contain geological reserves in the order of 62 million tonnes containing asbestos fibre similar in value to the Cassiar deposit.The McDame is considered a major world-class asbestos deposit. A decision to develop and mine the deposit will require further substantial underground exploration and evaluation. A + 1200 m exploration adit driven to the hanging wall of the deposit was undertaken in 1985 in anticipation of bulk sampling and diamond drilling in 1986."

Jan 1, 1986

By Henry A. Stiff, Lawrence E. Davis

A graphic method was developed which can be used to predict the tendency of oil field waters to precipitate calcium Sulfate under a variety of conditions. Application of this method is made to the prediction of sulfate scale formation in heater treaters. boilers. oil wells. cooling systems and water injection wells. INTRODUCTION A solution may be said to be in equilibrium with respect to a given salt when the concentration of that silt in equal to its solubility. If for any reason the concentration of the salt is increased or its solubility decreased. the equilibrium is upset and precipitation of the salt takes place. Thus, if the concentration of a salt in a particular solution is known and its solubility can be calculated for a given set of conditions, the tendency of this salt to form a precipitate under these conditions can be predicted. Based on these principles a method has been developed for determining the tendency of oil field waters to form calcium Sulfate precipitates under various conditions. THE SOLUBILITY DIAGRAM Calcium sulfate precipitation most frequently occurs when two waters are mixed: one containing calcium ions. and the other sulfate ions. As one of these waters is added to the other a point may be reached where the concentration of calcium Sulfate is greater than its solubility. thus causing the formation of a precipitate. The solubility diagram is a graphic device for determining the location of such points, thereby making possible a prediction of the tendency of such a system to deposit sulfate scale. A similar diagram can be used to solve many other problems involving the precipitation of calcium sulfate. Fig. 1 shows a solubility diagram representing the mixing of two waters. Water "A" contains a high concentration of odium, magnesium, and sulfate ions together with a small amount of calcium. Water "B" contains a high concentration of calcium ions together with sodium, magnesium and a small amount of sulfate ions. The percentage mixture of these waters is plotted along the abscissa of a system of rectangular coordi-

Jan 1, 1952

The Western World's gold reserves now exceed 23,000 mt (750 million oz), 65% of which exist in South Africa. Although several major mines are reducing production or closing because of depletion of reserves, new mines or expansions of existing mines are coming on-stream which will maintain an annual production of 684 mt (22 million oz) of gold well into the 1990s. These new operations by the South African mining industry represent the largest expansion since the opening of the Witwatersrand gold fields in 1886. Included in three new mines being opened is that of Anglo American Corporation's Elandsrand plant, their fir& new gold venture in South Africa in seventeen years. Current average grade of South African mines is 8.2 g Au per mt (0.24 oz per st); and while the cost of the Elandsrand 135,000 mt (149,000 st) operation, including mine development, was about $314 million, it is estimated that the cost of a comparable operation started today and completed in the mid-1980s would be of the order of $480 million. New mines to exploit low-grade ore bodies are, therefore, likely to be few in number, and further expansion will undoubtedly be in the form of extensions to existkg operations where cash flow can be used to finance development. The authors' first monograph, "Gold and Silver Cyanidation Plant Practice," devoted a section to South African cyanide plant operation; and it is believed that this new volume would not be complete without a description of Elandsrand, South Africa's newest gold plant. The Elandsrand mine is adjacent to Anglo American's Western Deep Levels on the Far West Rand. The decision to go ahead with the development was taken in mid-1974 from the results of exploration drilling carried out over a period of .lo years. Results of 17 bore holes and 68 intersections of the Ventersdorp Contact Reef had indicated a gold-.bearing reef less than one meter thick at a depth of 1,800 to 3,000 meters (5,900 to 9,840 ft). Preliminary studies indicated a mine of 900 km (560 miles) of underground workings would yield 725,000 kg (23. 3 million oz) of gold from 60 million mt (66 million st) of ore to be milled over a period of 34 years. Eventually, when the mine is in full production, the total hoisting capacity will be 300,000 mt per month (331,000 st) for a milling capacity of 225,000 mt per month (248,000 st). The Elandsrand surface facilities have been built on a low range of 0 hills to take maximum advantage of the 10 slope in transporting ore

Jan 1, 1981

Alfred E. Hunt, Pittsburgh, Pa. (communication to the Secretary): My experience has been similar to that described by Mr. Sperry, regarding a 50 per cent. alloy of nickel and aluminum. Moreover, the same phenomena occur with a 50 per cent. alloy of iron and aluminum, manganese and aluminum, chromium and aluminum, or tin and aluminum. It seems that there is a narrow limit of composition of these metals, within which, when they are alloyed, they crumble down into a powder after standing for any considerable time. The resulting powder does not seem to be a separation or disintegration into the elements composing the alloy, but simply a powdering down of the alloy itself. The physical properties and utility of any of these alloys in pondered form have not been carefully investigated as yet, and offer a field worthy of further investigation. Samuel Peters, Pittsburgh, Pa. (communication to the Secretary) : In the early seventies, during the early days of the open-hearth process in this country, the writer was engaged as

Jan 1, 1900

By S. J. Broderick

"INTRODUCTION Dark soils are commonly believed to be better for agricultural purposes than light-color soils. Much of this feeling may be purely psychological, as many persons have unconsciously acquired the habit of associating richness of soil with color light soils, however, may be just as rich in humus and plant foods as the best of the dark soils. A dis-cussion of the manifold attributes that play an important role in soil technology is beyond the scope of this paper, but the color factor will be considered, as it has a particular bearing on some field experiments using coal-mine waste as a darkening medium.It has been established that dark soils absorb more of the sun's radiation, consequently are maintained at a higher temperature than light soils. This physical principle is applied in our daily lives in the choice of clothing. White clotnes in summer are cooler than dark ones. Conversely, dark clothes in winter are warmer than light-color clothing. A decided advantage of dark soils over light soils is the higher average temperature of the former, resulting in an earlier maturing crop. This advance of the maturing season may range from a few days to a month, depending on such factors as climate, crop, and degree of color of the soil. It has been reported that in parts of Russia where the growing season is short, perhaps comparable to that in Pennsylvania and. New York, cotton has been grown successfully on soils originally of light color, but darkened with coal, dusts. The growth of cotton is, accordingly, speeded up a full month. 3/"

May 1, 1940