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By Monger N. R

Factors leading to the decision to use Joy Continuous Miners for pillar extraction in the Burwood Colliery are outlined. A detailed description is given of the Joy 1-CM-2 Continuous Miner, including the power supply to the machine, and the method of cutting coalfrom a face. Modifications found necessary in practice are dealt with.The Joy 10 S.C. shuttle car used in conjunction with the Miner, and alterations made to this unit, are then described, together with Ancillary units for the whole installation such as transformers, motor generator set, air compressor,_ cables for power supply and water supply for dust suppression.Special arrangements were necessary to transport the Miner and Shuttle Cars through the tunnel to the Victoria Tunnel seam, and the method of overcoming the transport difficulties is discussed. Manning of the Continuous Miner unit, and final preparation andsubsequent working of the pillars is outlined. Special attention must be given to maintenance of the machines.It is concluded that the combination of Joy Continuous Miner and Shuttle Car is an excellent method for removing pillars in the Burwood Colliery.INTRODUCTIONThis paper deals with the Burwood Colliery in the RH.P. Group in which some units are engaged in the mechanical extraction of pillars with Joy Continuous Miners.In 1941, an amendment to the Coal Mines Regulation Act of N.S.W. forbade the extraction of pillars by mechanical means unless with the express permission of the Minister for Mines. As this permission was not forthcoming, no mechanical extraction of pillars took place in Australia until 1954 As it was doubtful during most of this period whether mechanical extraction would ever come about, coal generally was won with a view to maximum extraction in the first workings, thus giving rise to centre gannon bord panels and 45° angle cut throughs as shown in Fig. 1.

Jan 1, 1957

By Edwin Dudley Martin

DURING the past twelve years the iron and steel industry has made a major advance through the development of the continuous wide strip rolling mill. So far-reaching have been the results that not only has a better product been sold at a lower price but this improvement in quality has permitted manufacturers of products using steel to make important savings in the cost of fabrication. The net result has been a better product at lower cost to the consumer without reduction in either employment or of wages paid within the industry. That is why the iron and steel industry is proud of its attainment. Being a basic industry of strategic importance, such an advance in technology has had its effects on our internal economy, our standard of living, and our industrial power as a nation in both peace and wartime.

Jan 1, 1939

By W. E. Roscoe, H. Agnerian

The contour method can be used to estimate the mineral resources of a mineralized body. It relies on geological interpretation and allows the geologist to determine the plunge of a mineralized ore shoot along the dipping plane of the mineralized body. The technique is best applied to estimate tonnage and average grade of relatively planar bodies, i.e., where the two dimensions of the mineralized body are much greater than the third dimension, such as Archean lode gold vein deposits or mantos of massive sulphide mineralization, based on exploration drilling. For these types of deposits, the contour method can provide a clear view of the “mineralization landscape” with “peaks” and “valleys” along the plane of the mineralized vein. The technique also reduces the “nugget effect” of local high values commonly present in gold deposits. With sufficient drill hole information, the contour method may be used to estimate the tonnage and average grade of individual blocks within a mineral deposit. General procedures for the contour method are described in this paper, along with examples and explanatory notes.

Jan 1, 2002

Tin mineralization in both eastern and western Tasmania shows a spatial correlation with middle Palaeozoic biotite granites and adamellites. The range of composition of these granitic rocks is restricted with respect to Mg, K, and Na content. Because this compositional restriction is shown by granitic rocks from other tin provinces, the concept of a genetic relationship between these granites and the associated tin mineralization is reinforced, and similar concentration mechanisms may be involved.Gold mineralization is largely restricted to eastern Tasmania and in contrast to the tin mineralization is rarely spatially associated with the middle Palaeozoic granitic rocks, although most authors have suggested a genetic correlation with hornblende and/or biotite granodiorites.Although few analyses are available, the granodiorites that are spatially associated with gold deposits exhibit similarities to granitic rocks from gold provinces elsewhere. These features suggest a possible genetic relationship between gold mineralization and the granodiorites.The composition of granitic rocks may be used as an aid to exploration in delineating areas of potential tin and gold mineralization in granite terrains.

Jan 1, 1970

Drilling at Ipswich during the last twelve years by the Queensland Department of Mines has proved large quantities of reserves which have assured the security of the field for many years to come. This is perhaps the greatest contribution to the development of the field since its discovery in 1827.The drilling campaign commenced in 1950 and by the end of 1961 comprised 242 holes totalling 180,220 ft.Intersections of formations and seams, accompanied by detailed surface mapping, led to more precise knowledge of the geology of the field than was previously possible, and clarified many problems of correlation. Productive formations are part of the Middle Triassic Ipswich Coal Measures, a 4,300 ft sequence of fresh-water sediments with some interbedded volcanics. They are overlain by the Upper Triassic Bundamba Group and the Lower Tertiary Booval Group.Reserves disclosed by drilling amount to 171,487,000 tons, comprising 109,407,000 tons "measured" and 62,080,000 tons "indicated". The security of these reserves encouraged many collieries to instal modern efficient mining machinery and washing plants.The climax of recent development of the resources of the field will be the commissioning in 1966 of a £33 million 360 MW power station in the Swanbank district which will consume 14 million tons of coal during its 30 year life and will have a peak demand of some 20,000 tons per week.Drilling is continuing and is expected to prove additional reserves which will justify further development of the field.INTRODUCTIONUntil 1949 there had been no concerted effort to test systematically the resources of the whole Ipswich field. Fifty two known holes totalling 30,500 ft had been drilled, eight of them by the Department of Mines, but because of poor core recovery and inadequate records most of them were of little use in a comprehensive assessment.Development of the field was being retarded by uncertainty regarding reserves and by the general state of the coal mining industry. Numbers of comparatively small independent companies and owner groups were operating coal...

Jan 1, 1963

Detailed mineralogical investigation of a tailing sample from the Juno plant circuit at Tennant Creek was carried out to determine the nature of the unrecovered bismuth and whether any possibility existed for improving bismuth recovery. The investigation showed that the Ibismuth was present in a complex mixture of Bi-Pb-Ou-Se-S minerals (termed "bismuthinite"), of which about 74 per cent was locked (mainly with magnetite) and 26 per cent was liberated (18 per cent in the minus 7 µm slime). The results suggested that attention should be directed to both finer grinding and improved flotation of slime "bismuthinite", and testwork carried out by Peko Mines N.L. on the basis of these recommendations led to a significant improvement in bismuth recovery.Detailed mineralogical investigation of two Juno concentrates was carried out to determine the nature of the selenium present and whether any possibility existed for improving the selenium grade. The investigation indicated that virtqally all the bismuth, selenium, and lead was present in "bismuthinite", which showed a composition range of 32-82 per cent Bi, 0-42 per cent Pb, 0-24 per cent Se, and 5-18 per cent S. Differences in the Bi/Se ratios of the two concentrates could be attributed to different average Bi/Se ratios of the constituent "bismuthinite", and the relatively low selenium grade of the "bismuthinite" precluded the possibility of obtaining a high grade selenium concentrate with high selenium recovery.However, differential flotation and/or low intensity magnetic separation to remove chakopyrite, and magnetite, the main diluents of the concentrate, could be expected to upgrade the selenium content byup to 80 per cent (relative) and .festwork carried out by Peko Mines N.L. on the basis of the recommendations of the mineralogical investigation confirmed that depression of chalcopyrite in the flotation circuit could produce significantly improved selenium grades.These investigations illustrate the application of mineralogy to the practical problems of improving plant performance. Mineralogy has an important role to play in providing quantitative data on which the metallurgist can evaluate plant performance and base a programme of metallurgical testwork, and early mineralogical investigation of feeds, concentrates, middlings, and tailings can lead to the avoidance of much abortive and expensive metallurgical testwork.

Jan 1, 1974

By Gerhardt A. Bennewitz

The mechanism shown here (Fig. 1) may not be all that it appears to be. To many of you it may look like a hopper car, a thing of mobility, in which you would ship coal, ores, limestone, or other bulk materials. It is approximately 50 feet long, 12 feet high, and can be placed on tracks which are on approximate 14 foot centers. But far too often in the past, and all too often today, this mechanism has been made to serve as an immobile storage box, with its primary role -- the transportation of products, seemingly incidental to the storage function. Our engineering training teaches us to conserve resources, despite some of the popular and misconceived philosophies being advanced these days. Those of you who work for companies with traffic departments know that they are always striving to reduce the price which is paid to move your mine products. Today, let's consider and analyze the ways in which the cost of transporting your mine products might be reduced, based on particular reference to coal. Bear in mind that in this context, cost and price are not necessarily synonymous. Until a few years ago, most coal and other bulk materials handled by railroads moved under standard tariff rules. These rules, which still exist today, provided transportation vehicles (railroad cars) for extended periods at no added price to the shipper or receiver. "Normal" free time rules would permit a car to be held for a maximum of 48 hours without charge; however, in the case of coal, there is a rule which, subject to liberal rules as to the

Jan 1, 1972

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

Fines and unnecessarily small rock fragments are created by as many as four identifiable breakage mechanisms which operate close to the charged section or sections of the blasthole. The peak blasthole pressure (Pb) should not exceed that value at which the rock starts to fail in compression. Excessive Pb values can be prevented by carefully selecting:1. the composition, density and/or diameter of the charge, and2. the initiation/priming system.The percentage of fines increases with:1. increases in the charge diameter:blasthole diameter ratio, burden distance, blasthole diameter, effective sub-drilling and size of blast, and2. decreases in blasthole spacing, stemming height and the length:width ratio of the blast block.Decked charges tend to reduce the percentage of fines.Excessive fragmentation is more evident in buffer blasting and sinking cut shots than in blasts fired to a clean free face. Initiation sequences which give effective burdens considerably less than drilled burdens encourage the minimization of fines, as does an inter-row delay time which promotes good progressive relief of burden.The wastage of explosive energy in creating fines is most pronounced where fully-coupled, energetic charges are fired in weak and/or highly porous rocks. This is especially so where forward movement of the strata is impeded by buffer rock, excessive burden distances and/or inadequate inter-row delay times.

Jan 1, 1979

By S. Kitamura

In recent years, the amount of ferritic stainless steel production has increased. However, the rust formation by the salt spray test was pointed out in the past. At the centre of the circular rust zone, pitting corrosion where water-soluble nonmetallic inclusions were embedded was observed. These inclusions originated from the suspended refining slag and consisted of multi-phase oxides and sulphides. By the experiments and thermodynamic consideration of the water-solubility, not only CaO or CaS, but also lime rich calcium-aluminates or calcium-silicates have shown large water-solubility. The composition of oxide phase in the inclusions was almost the same among the samples from molten steel, slab, or cold rolled sheet. On the contrary, CaS was clearly observed around the oxide in the sample of cold rolled sheet, although it was not found in the molten steel or slab samples. The enrichment of sulphur occurred from the desulphurization reaction of the suspended slag particles in the molten steel and also occurred from the diffusion of sulphur to the oxide inclusions during the heating of the slab. The optimization of refining slag composition has lead to produce the ferritic stainless steel without rust formation. Keywords: stainless steel, rust, calcium aluminates, calcium sulphides, water-solubility, refining slag, composition control of inclusions.

By Hindmarsh J. W, McCoy A. E R

Instantaneous outbursts of coal and gas have occurred at various times in several working districts of Metropolitan Colliery, N.S.W.They have occurred in headings only, under both hand and mechanised conditions, and with seam gas ranging from mainly methane to nearly pure carbon dioxide. A modification of inducer shotfiring using a shear cut was introduced in 1955, and in 1961 full face firing both to a machine cut shear and off the solid was introduced. The current series of outbursts -1961 to 1963 - has been induced under these systems with full control of the time of outburst, but without prediction, and with some disappointing production features.Various aspects of current conditions and practices at Metropolitan are considered singular, such as the coarse granulometry of outburst coal, the prevalence of floor heave, the absence of strong structures at outburst sites, the possibility of outburst at any stage in pillar formation up to the last few yards, the effect of rate of advance on outburst occurrence, and the mildness of many outbursts experienced.It is concluded that inducer shotfiring is a reliable control but it suffers by comparison with outburst-free conditions, and that control by preyention would be preferable.INTRODUCTIONThe phenomenon of instantaneous outbursts of coal and gas has been described in detail previously (Hargraves, 1958). Briefly, it is a combined gas and stress hazard of deep coal mining, usually occurring in virgin work and during active face advance, when coal and seam gas burst from the face into the workings.Instantaneous outbursts have occurred sporadically at Metropolitan Colliery, N.S.W., since 1895. Early outbursts were recorded as firedamp and recent outbursts are of blackdamp.Mining methods used have been conventional hand work, with progressive and relatively complete mechanisation over the past 25 years to substantially conventional...

Jan 1, 1964

By Thomas Donnelly

Introduction THE Province of San Cristobal is situated on the south side of the island of Santo Domingo about 25 miles west of Santo Domingo city, the capital of the republic. The copper mineralization is found about 1.-CAMP BUCARO. THE TOP OF THE RIDGE IN THE BACKGROUND MARKS THE CONTACT OF THE LIMESTONE AND TUFFS. S miles north of the town of San Cristobal, in the section known as Bucaro Hill; in San Francisco Hill; on the Nigua River; and on the Jaina (Liver. The district is reached by automobile from Santo Domingo city over an excellent road for 25 miles to San Cristobal, and then, by horse-back 6 or 8 miles up the Nigua River to what is locally known as "Camp

Jan 8, 1915

By H. C. Goodrich

THE earliest record of copper production from the state of Utah comes from "The Resources of Utah," by. Mr. Fabian, in 1872, wherein it is stated that the. Mammoth mine of East Tintic was located in 1870 and that the ores yielded a large percentage of copper, silver and gold. It is also stated that shipments had been made to Swansea, England, which assayed between $200 and $300 per ton. The Mammoth-Copperopolis mine was located in, 1870 and sold the year following to an English syndicate. Some copper was shipped to. England and in 1873 there was constructed a 15-stamp mill and two copper smelting furnaces; these were operated a few months and before the end of the year were closed down and the property sold for debt. . This property -vas reorganized in 1879 and is at the present day a producer, though its principal product now is lead and silver. While a certain amount of copper has always been coming from the various lead-silver camps of Utah, the real history of copper in Utah should start with the discovery of the mines in Bingham Canyon, located about 25 miles to the southwest from Salt Lake City.

Jan 1, 1925

In the course of the last twenty eight years the copper lodes of New Caledonia have been periodically worked or abandoned, until quite recently, probably attracted by the higher price of the metal, British capital has again been induced to embark upon the further development of several copper properties, which at present give reasonable promise of becoming regular producers. Owing to its proximity to Australia (only a three day's journey by mail steamer from Sydney) New Caledonia becomes of additional interest to Australian commerce in general, and it is to be hoped that the French Government may see their way before long to make the best of this natural position, to the mutual benefit of both countries concerned.Op till now all copper ores and concentrates which have been shipped from New Caledonia, were treated in Australian smelting works furthermore, Australian mine managers and miners have from time to time been connected with New Caledonian mining ventures, but, unfortunately, it must be said that nearly everyone of them returned to Australia thoroughly disgusted with his experience over there. Even to the casual observer, it is not so very difficult to find a proper explanation for these shortcomings in the peculiar economic conditions of the 'French colony, as many of the objections which have hitherto existed in connection with mining operations, were the direct consequences of a system of colonisation which could not possibly have been productive of better results.

Jan 1, 1901

By Arthur Notman

Since addressing the Institute a year ago on The Future of the Copper Industry (l), many things have happened, most of them bad. It has been a hard year for profits and prophets. It was, therefore, with consider-able perturbation that I accepted the gracious invitation of your Committee to reappear. On reviewing my remarks of a year ago, I. have wondered whether, under pressure of more important matters, the Committee had neglected to make a note of them, or whether they felt that further explanations from me were in order. In either event, I am glad that I am here and welcome the opportunity to make any contribution I can to a clearer understanding of the problems of copper to those concerned. The English-speaking nations own 80 per cent of the present world-production of the metal. Col. P. E. Barbour, Secretary of the Mining and Metallurgical Society of America, and I recently completed an estimate of the known world resources of copper. We placed the figure, in round numbers, at 100,000,000 tons of metal. Of this amount, about one-third lies in the United States, one-third in the British Empire, and one-third in South America; and all but 4 per cent of this is owned by British Empire and United States capital. Our figures do not include any estimates for Russia, Japan, or Europe, on which there are no available data. It is true, consequently, that the British Empire and the United States are the ones concerned. It seems to me to be a matter of great importance to the world at large, and of even greater importance to those nations themselves, that the known sources of supply of this metal, so essential both in peace and war, rest so strongly in their hands. I cannot believe that in the long run they will neglect their responsibilities in the wise administration of these resources.

Jan 1, 1932

By Sergio Demetrio

Based on the current reality of the copper smelters industry, besides the advances that have been and are expected for the next few years, the authors present a futurist vision of the processing of copper concentrates and copper smelters in the years 2000. Outlined new development strategies and ways of improvement in this business, including research, development and management of the works that today posses characteristics of a profitable operation, as well as the changes expected with respect to the entry of new actors and the creation of new products The authors finally bet for small or tailor-made smelters with ad hoc technology for their raw materials and few units to coordinate -devoted to specific concentrates using high technology and low manpower. Considering the in-situ hydrometallurgical route, as well as the pyrometallurgical route in works or conversion facilities that buy or process white metal and produce copper and other metals associated with this such as gold and silver, besides sulfuric acid, plants which should be strategically located in zones with high sulfuric acid price to make this a product which contributes to the profitability of the business.

Jan 1, 1999

The copper-clay deposits consist largely of goethite and clayey mudstones carrying native copper, cuprite, and chalcocite. The mudstones are of Ordovician age, are interbedded with Fe-Mn carbonates, and probably contained syngenetic iron and copper sulphides. The secondary copper minerals have been derived from post-Devonian weathering in situ and also by deposition from surfaee and underground waters draining the adjacent mineralized volcanic rocks.

Jan 1, 1969

By Jon Y. Kaneshiro, Ed Walton, Stephen J. Navin, Robert M. Sergeant, Storer J. Boone

The Coronado Traffic Tunnel is a proposed two-lane, reversible, road tunnel, which will relieve severe peak hour congestion problems on surface streets. The tunnel will take traffic from the Coronado Bay Bridge to Naval Air Station North Island. The project will include 12.5 m (41 ft) inside diameter by 1,112 m (3,650 ft) of tunnel, 552 m(1,815 ft) of cut and cover box structure, and 400 m (1,315 ft) of open cut structure. The geology consists of predominately clean and silty sand, saturated sand, with some clay layers, requiring Earth Pressure Balance or Slurry Shield tunneling technology.

Jan 1, 2001

By E. V. Lilford

Equity investors and project sponsors have divergent views about expected or minimum returns that should be generated by a mineral project. Irrespective of their views, the fundamental estimation of the corporate cost of capital remains singularly determinable, with additive components of risk and uncertainty often incorporated in the final analysis. This paper discusses and details the fundamental, numerical determination of the corporate cost of capital.

Jan 1, 2006

By Douglas D. Donald

The financial analyst's job is to make an objective appraisal of the investment opportunities which exist within the various industries under his supervision within the context of the economic model provided by his firm and the a climate of investor sentiments. Industry analysis is critical. When a major investment trend develops, usually the stock of all companies within the specific industry react in the same direction. I should emphasize here, however, that an investment trend is influenced by the economic outlook, but economics is not the only determinant - investor psychology and arbitrary political factors may be of equal or greater importance. Part of our job is to recognize trends early and determine whether they are valid. Following industry analysis, the analyst must examine the specific companies within that industry since some companies usually react more violently than others to industry trends, whether they be favorable or adverse. To simplify the process of evaluating an investment opportunity, it is convenient to isolate three types of factors which have a bearing on every sort of business although the degree of influence of each factor may vary from industry to industry. These categories are, 1) independent or external factors insofar as they are beyond the control of corporate management, 2) interdependent factors insofar as influence may be exerted by industry-wide action, and 3) dependent factors covering the area of internal decisions which are basically under the control of the individual corporate managers. Although the title of this paper, "The Corporate Use of Cash Flow," is only one segment of the third category, it may be useful to continent on the first two categories as well. The independent factors may be either economic or governmental. The economic factors include cyclicality which may be very high in the case of the basic commodity industries or relatively low as in the case of utilities. Underlying growth rates, another independent factor, may range from the business equipment industry with an annual growth rate of 14% through the electric utility industry with a growth rate of about 7% per year to the

Jan 1, 1970