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By Johnson T, Huynh D

The State Electricity Commission of Victoria is conducting a program of research and development into alternatives to the use of conventional boilers for the generation of electricity from brown coal. The objectives of the program are to reduce the cost of electricity generation and also to improve the thermal efficiency so as to reduce the emission of greenhouse gases and other pollutants. The program presently includes the following four technologies: Hydro-thermal Drying, Direct Coal Fired Gas Turbine, Integrated Gasification Combined Cycle, and Steam Fluidised Bed Drying. The Hydro-thermal Drying process produces a combustible coal-water-slurry fuel which is suitable for use in a coal fired gas turbine. The coal fired gas turbine has the potential to produce electricity at a lower cost than conventional power stations and when combined with a steam cycle, it will also use significantly less coal. The Integrated Gasification Combined Cycle process gasifies the coal, cleans the gas, and then bums it in a gas turbine/combined cycle. This process is being developed in Europe and the USA in order to meet their stringent emission regulations. It offers Victoria cleaner more efficient and cheaper electricity.

Jan 1, 1992

By Fawad S. Niazi

Ever since the use of the cone penetration test (CPT) in geotechnical practice, attempts have been made to correlate CPT parameters with pile capacity components of unit end bearing (qb) and unit shaft resistance (fp), thus deriving multiple CPT-based pile design methods. These methods focus on "capacity" only without consideration to complete axial pile load-displacement (Q-w) response. Estimated capacities from these methods also exhibit considerable scatter without any consensus on their consistency. In addition, load-displacement curves obtained from axial load tests on highly expensive and extensively instrumented piles can exhibit different shapes. Nevertheless, a single value from the curve so obtained dictates the design capacity. Currently, there are at least 42 different criteria defining capacity with considerable variation in the values obtained thereof. The Randolph elastic solution, which provides a framework for analytical evaluation of pile load-displacement response, requires the profiles of soil stiffness. The fundamental soil stiffness defined by the small-strain shear modulus (Gmax) can be obtained from shear wave velocity (Vs) readings via seismic piezocone tests (SCPTu). The secant stiffness (G), which softens from Gmax corresponding to operational load levels, can be obtained by generating stiffness reduction curves from back analysis of load tests. Then, using appropriate G values, the Q-w curve can be defined for conditions similar to the database from the pseudo strain (w/d). Thus, a complete framework for optimal integration of SCPTu data, Randolph elastic solution and back-analysis of field operational stiffness can be established for complete axial pile foundation analysis.

Jan 1, 2011

By Edmonds G. A

The power station went into operation in 1931, when the installed capacity was 12,500 kVA. with a loading of 4,000 kVA. In 1936 the loading increased to 6,750 kVA. which necessitated the addition of a third set which went into operation in 1937, the installed capacity at that date being 18,750 kvA. with a loading of 7,000 kVA. This remained fairly constant until 1945, when a gradual increase was noticed, the loading in 1952 being 10,598 kVA.With the addition of the copper plant, additional generating capacity was required and it was decided to raise the installed capacity by the addition of a fourth set to 34,375 kVA. with an expected loading, when producing copper, of 20,000 kViA.MAIN POWER PLANTThis consists of three GiE.e. alternators of 6,250 kVA. or 5,000 kW. at 0.8 P.F. rating and one G.E.C. alternator of 15,625 kVA. or 12,500 kW. at 0.8 P.F. rating, making a total generating capacity of 34,375 kVA.Each alternator is driven by Fraser and Chalmers turbines at 3,000 r.p.m.SYSTEMThe main 3 phase 3 wire 3,300 volt distribution system has the neutral point of alternators earthed through by one or two earthing resistors designed to limit earth fault current to 3,000 amp. for 20 seconds, in the case of the large machine, and to 1,100 amp. for 10 seconds, in the case of the smaller machines, or full load of either size machine at rated voltage.

Jan 1, 1953

By Jiuhua Xu, Yuling Xie, Fenglei Bie, Neng Jiang

"Abstract - The Xiaoqingling Mt. area is one of the most productive gold districts in China. The gold-bearing quartz veins are controlled by a series of east-west shear zones within the Archean Taihua Group, and related to the late Yanshanian (Cretaceous) granite. The major metallic minerals are native gold, electrum, pyrite, galena, chalcopyrite and sphalerite, with gangue minerals dominated by quartz, sericite, ankerite, and calcite. The host rocks are mainly amphibolite, plagioclase gneiss, and migmatites. Principal alteration is sericitization, silicification, pyritization, and carbonization.There are four generations of hydrothermal quartz in altered rocks of gold deposits. The earliest generation of quartz, (Q1), occurs in altered amphibolite gneiss and migmatite, and typically contains fluid inclusions with halite crystals (type A) and two phases, (L+V), of fluid inclusions (type B). The salinities of type A inclusions are 32 wt% to 52 wt%, with dissolution temperatures of halite crystals being from 155°C to 465°C. The second generation of quartz, (Q2), occurs as a fine-grained aggregate associated with sericite, and has small (less than 3 µm) type B inclusions. The third generation of quartz, (Q3), occurs in mylonitic, intensively altered rocks and specially beresite (a type of rock composed of quartz, sericite, and pyrite) near the veins, and contains large amounts of CO2-rich fluid inclusions (type C-fluid inclusions with liquid CO2 and type D-fluid inclusion with high density CO2). The CO2 contents of type C range from 72.6 to 87.4 mol% in gas phases, and 35.7 to 68.3 mol% in liquid phases, based on Laser Raman analysis. The homogenization temperatures of fluid inclusion type A and C are from 215°C to 380°C, and from 210°C to 325°C, respectively. The minimum trapping pressure of fluid inclusions is estimated as 80 MPa to 170 MPa for type A, and from 57 MPa to 190 MPa for type C, which approximate to those of fluid inclusions in vein quartz.The ?18O of quartz are from 10.4‰ to 11.0‰ for Q3 of altered rocks, and from 10.7‰ to 12.8‰ for stage I quartz. The calculated ?18O of fluid inclusions varies from -1.3‰ to 6.0‰. The ?D of fluid inclusions ranges from -67‰ to -59‰ and from -81‰ to -48 ‰, respectively. It is concluded that the water in the hydrothermal fluids both reacting with wallrocks and precipitating orebodies could have been mainly of magmatic and/or metamorphic nature. However, local meteoric water might have been important in late mineralization, because of a distinct oxygen-shift toward the meteoric water. The ?34S values for pyrite of the ores range from -7.1‰ to +7.1‰, with an average of +2.9‰. Those of other sulfides (chalcopyrite, galena, and sphalerite, range from -12.5‰ to 8.3‰. The ratios of lead isotopes for galena of the ores are: 17.06 to 17.31 (206Pb/204Pb), 15.43 to 15.74 (207Pb/204Pb) and 37.58 to 38.45 (208Pb/204Pb). In summary, ore-forming fluids in the Wenyu-Dongchuang gold deposits may have originated from a mantle and/or lower crust source, and ore materials were derived from the Precambrian basement, the Taihua Group."

Jan 1, 1998

By A. C. Fieldner

"Decline of the Beehive Coke OvenTwenty years ago a favorite theme of the crusader for fuel conservation was the enormous waste of valuable by-products incurred in the manufacture of blast-furnace coke in beehive ovens. Indeed, there was good reason for arousing the national conscience to this needless' loss of an irreplaceable mineral resource. In 1910, 83 per cent of the coke production was made in beehive ovens, from which surplus gas, tar, light oil, and ammonia, aggregating in value (at 1910 prices) 40 million dollars annually, were discharged into the atmosphere.In 1929, proportions were reversed and 90 per cent of the production was made in by-product ovens. The average value of by-products obtained in the production of 1 ton of coke in 1929 was $3.60, as compared with $1.16 in 1910, although the value of a ton of coke had increased only from $3.47 to $4.80. As shown in Figure 1,1 the production of by-product coke progressed rather slowly until 1915. War needs suddenly expanded the demand for coke and the by-products benzol and toluol for the manufacture of explosives. Except during the depression of 1921, this accelerating rate of production was maintained up to 1929, largely at the expense of beehive plants. The 1929 production of 60 million tons of coke will probably remain a record-breaking figure for several years. The developments which are now in progress in long-distance transmission of rural gas and in the utilization of volatile petroleum products and refinery gases for augmenting, city gas supplies may retard an other- wise accelerating demand for coke and coke-oven gas for domestic and industrial heating, Trends in Value of By-ProductsThe increasing value of by-products in comparison to the value of coke is shown in Figure 2. In 1913, the average value of by-product coke was $3.38, the value of the by-products per ton of coke was $1.41, and the cost of coal per ton of coke was $3,27, In 1929 not shown in figure) the value of the coke had risen to $4.80 per ton, the value of the by-products to $3.60, and the cost of coal per ton of coke to $5.07. The by-product values in were 155 per cent higher than in 1913, although the coke value had increased only 25 per And the cost of the coal 55 per cent. Actually the increase or the total value of coke plus by-products in this period was very little more than the increase in the coat of the coal, being 55per cent for coal and 60 per cent for coke plus by-products."

Mar 1, 1931

By Jr. Sillers

To prove to .the satisfaction of all concerned that electrolytic manganese from our low-grade domestic ores could be substituted satisfactorily for ferro-manganese made from high-grade foreign fires, an extensive series of tests was conducted in cooperation with industry, in which electrolytic manganese pro-duced by, the Bureau of Mines at its Boulder City, Nev., Station was substituted for the ordinary ferro grades in the production of ferrous and nonferrous metals and alloys and welding-rod coatings. Over 1,200,000 pounds of manganese was given out for this purpose. The objectives of the tests were accomplished, and for some purposes electrolytic manganese was shown to be superior to other grades because of its high purity. The only serious objection that can be raised against electrolytic manganese is its price, which puts it out of reach for most purposes. Even if the price were to be lowered to a point where it would be in line with ferro grades, it is questionable whether electrolytic manganese from domestic ores could supply more than a small part of the needs of American industry because of the large volume of domestic ore that would have to be processed to supply a satisfactory feed for the electrolytic process. Thus, although electrolytic manganese is highly desirable from a metallurgical standpoint, it could not be expected to substitute for more than a fraction of our domestic manganese requirements.

Jan 1, 1952

By T Hughes

The Gekko InLine Pressure Jig (IPJ) was unleashed on the World gravity separation market in 1996 and has since sold over 150 units in applications including tin, diamonds, silver, coal, garnet and gold. During the past twelve years the knowledgebase of the best applications and capabilities of the IPJ has greatly increased. Improvements to the original IPJ design have included engineered ceramic ragging in specific gravities from 1.6 to 5.0, full automation and improved designs of feed presentation and tailings and concentrate handling systems. The IPJ has been found to be able to handle a wide feed size range and recover mineral at liberation size without significant addition of water to the mass balance. Test work carried out during full-scale operation of the IPJ has shown the IPJ can recover diamonds down to 0.5 mm, sulfides down to 0.3 mm and gold down to 0.1 mm which greatly expands its application in the mineral processing industry. A significant volume of data now supports the symbiotic benefits of an IPJ and flotation circuit combination to pre-concentrate an ore and minimise downstream processing requirements.

Jan 1, 2008

By Henry P. Wheeler

H ELIUM (chemical symbol: He) is a member of a family of normally gaseous elements, which, because of their zero valence and corresponding lack of chemical activity, are called the "noble" or "inert" gases. It is a monatomic element with an atomic number of 2, and it exists naturally in two stable isotopic forms-He3, with an atomic mass of 3.0170, and He4, with an atomic mass of 4.0039. With the exception of a trace (10-6 percent) of He3, all of the naturally occurring helium is He4. Two unstable isotopes-He5, with atomic mass 5.0137, and He6, with atomic mass 6.0208-are listed by various scientists, but the existence of He5 is questioned by some of them. He6 is radioactive, with a half-life of 0.8 second. Helium was discovered in 1868 in the gaseous atmosphere surrounding the sun. Although several scientists studied the solar chromosphere that year, it is generally agreed that J. Norman Lockyer of England should be credited with the discovery of helium, which he named, deriving the word from "helios," the Greek name for the sun. It was not found on earth until March 1895, when William Ramsay of London produced a small amount from a sample of cleveite, a uranium-bearing mineral. In 1905, H. P. Cady and D. F. McFarland of Kansas found helium in natural gas produced from a well near Dexter, Kans., and for the first time a large source of helium became available.

Jan 1, 1952

By G. R. Robinson

Aggregate resources consist of sand and gravel, and crushed stone. They are large-tonnage, bulk-minable mineral commodities that are used in construction and industrial activities (Tepordei, 1999, 2001).Rates of aggregate production, use and mine permit approval in the mid-Atlantic region differ by population density. These rates are influenced by economic and human factors, such as demand, costs, land availability and community opposition. In some areas, the local availability of aggregate is limited. This is due to the lack of suitable local source materials for aggregate, the loss of potential high-quality aggregate resource production sites by preemptive land development and restrictive zoning (resource sterilization), and the difficulty of developing and permitting production sites for aggregate.

Jan 1, 2004

By Russell Barr, Robert E. Cook

As most mining companies are taking advantage of the high market prices for base metals such as steel, copper and zinc, numerous challenges still face them. While demand is strong from countries like China and the United States, demand is still mixed in Europe. This leads to the question of how long these high prices and overall high global demand will last. The tremendous market prices of most precious and base metals have enabled many companies to pay down a significant amount of debt accrued during acquisition and capital expenditure phases. Additionally, mining companies have been able to internally fund and engage in large projects to address future growth, (Less, 2006), thus maximizing the performance of the existing asset base, driving maintenance costs down, and improving and empowering the work-force (Mining Journal, 2006). Market prices and general efficiency gains have addressed these issues to some extent. However, critical issues still face operating managers in the mineral pro-cessing side of the industry. Energy prices, for example, continue to have a negative impact on cash costs for producing an ounce of gold or ton of a given base metal (Cummins, 2003).

Jan 1, 2007

By Probert D. H, Wright E. A, Taylor B. L

A general description of the geology of the Southern Coalfield is given. The relationship between the Illawarra Coal Measures, the overlying Triassic and the underlying Upper Marine Series, of Permian age as are the Coal Measures, is briefly explained and thestratigraphy of each is described. The eight coal seams are then treated in slightly more detail as to their thickness, quality, areas of distribution and best occurrences.In the last few years each of the authors has been concerned with one phase or other of the stTucture of the field in detail or in mining operations with the result that it is now possible to name a number of monoclines, anticlines, domes and synclines defined in detail. A minor quantitative study has been made of faults and dykes with regard to form, direction intensity and inter-relationship. It seems probable that with the further collection of data a more detailed study in these matters will be of considerable value to the economy of mining in the Southern Coalfield.

Jan 1, 1958

By Madgwick J. C

Leaching column techniques and microbiological methods have been described in detail in Madgwick and Ralph (1980) and Madgwick, Ralph and Sadler (1981).Sixty-nine kilograms of copper porphyry ore (0.4 per cent Cu, 2.7 per cent Fe) (particle size 2.4-11.2 mm; 60 The effect of sodium chloride (O.6M) irrigation on bacterial leaching of Bougainville copper porphyry ore was studied.Viability of suspended Thiobacillus ferrooxidants was reduced to less than 10 cells/ml in NaCI (O.6M) compared with 10' eells/ml in dilute II,SO, (0.01 M, pll 2). Salt irrigation had no significant effect on heterotrophic and sulphur oxidizing bacteria. Increascd short term recovery of copper (145 g/tonne/ 15 days) was followed by a marked decrease in tenors to less than 20 mg/litre/day compared with an acid leach, steady release, of 110 mg/litre/day. Resumption of acid leaching restored average solution copper to 46 mg/litre/day and the viability of suspended T Ierrooxidates to 10 cells/ml.Quantitative removal of sodium ehloride from ore particles was difficult and t races of NaCI remained for more than 200 days.

Jan 1, 1982

By Dean Workman

Located in downtown New York City, this project necessitated an innovative conveyor design for successful muck removal. This paper will discuss the technical challenges and engineering solutions of the muck transport system which consists of every commonly recognized version of a belt conveyor. The elaborate system includes a TBM conveyor integral to the back-up system, a wall-mounted extensible conveyor, a crown-mounted transfer conveyor, a floor-mounted fixed-length conveyor, a pocket-belt vertical conveyor, three cascading overland conveyors, and one radial stacker. The most challenging design element was an over-land conveyor featuring a box truss for muck transportation over Northern Boulevard while simultaneously going under the Queens Plaza railroad viaduct. An overview of the project is provided along with the following topics: developing final plans from the proposal concept, interfacing with existing works, communication with the joint venture, and complying with local regulations.

Jan 1, 2008

Coking coals are very much in demand on a world wide basis, particularly the higher rank coking coals, which form an important part of many coking blends and which represent the smallest portion of the world'scoking coal reserves. Conventional coke oven plants, using these coals, will predominate at least until the next century.Blending schemes for conventional coking require definition of the basic properties of coals so that the factors influencing the carbonization behaviour may be assessed. Several concepts, which are relatively simple, ate available to help promote a better understanding of the bask factors controlling -coke strength and are also useful in suggesting possible lines to follow in the blending of coals for coking.The interpretation of carbonization behaviour and coke structure in terms of petrographically defined coal rank and type provide a basis for planning and exploitation of coal Teserves. The optimum parameters for coking are suggested as follows.1. Type- Vitrinite content (% m.m.f. by volume) 55 ± 5%2. Rank- Mean maximum reflectance of vitrinite 1.30 ± O.10% Carbon content of vitrinite (% d.m.m.f.) 87·5 ± 1·0%The value of a coal should be assessed in relation to all its possible uses in blends. This is a more realistic and productive approach, as compared with considering coals only in relation to the results of blending with"good" coking coals. Blending schemes have been outlined to assist in the assessment of the blend potential of coals of all ranks and types.Reserves of higher rank coking coals in N.S.W. are very limited and should be conserved by blending with the low rank coking coals, of which there are large reserves.Examination of blending theories in relation to N.S.W. coals suggest that blends in the broad categories of minimal downgrading of the higher rank N.S.W. cok...

Jan 1, 1972

By Prince Gelasio Caetani

PRESIDENT DWIGHT'S invitation to be a guest of the American Institute of Mining and Metal-lurgical Engineers was the first of the subsequently very numerous invitations to dinner I have received from my American friends. When I received his telegram I had not yet been even formally appointed Ambassador. I cannot tell you how deeply I appreciated it. It was a hearty welcome in returning to your country which has been for me a second home and it came from the American mining brotherhood which has been my second family.There are two distinct periods of learning in life. The first one are the years spent in school where we learn many things we after-wards forget; the second one are the years of prac-tical apprenticeship which engrave indelible signs in a man's character and shape his life. These latter years I spent in the United States and they have influenced the whole course of my life. I owe very much to my American friends who trained me. The earliest was Prof. Robert Peele, of Columbia University. At the Daly West mine, in Park City, Utah, he curbed my futuristic English spell-ing and had a hard time at it. Prof. James F. Kemp taught me that geology is a guess work just as unre-liable as the prediction of international events; he taught me also that a frank, honest and loyal character will lead a man equally straight through a mining report and through public life.

Jan 3, 1923

There are no large rivers in Western Australia capable of supplying water for processing magnetite ores. If sea water is used there are severe corrosion issues and the requirement to wash the concentrates with potable water. If groundwater is used there is a need to treat the water and sustainability is an issue for large projects because of potential drawdown of the aquifer.If sea water is desalinated the cost of the water is high because of the power requirement. At the same time the necessity to conserve water has lead to flow sheets where all of the tailings have to be filtered to minimise the water requirement.Managing the various water qualities and optimising water recovery and quality has resulted in optimising the water balance and issues meeting environmental obligations. Reverse flotation is a critical final step in reducing the silica level in the final concentrate and requires good quality water.

Jan 1, 2009

By Rex E. Loesby

The marble deposits of Yule Creek were first discovered in the late1870s. Minor quarrying occurred between that discovery and the early 1900s. Major development occurred in 1905, when Channing Meek, with some help from the Rockefellers, raised $3 million to develop the Colorado Yule Marble Quarry. That is $50 million in today’s dollars. Some of the words used to describe the marble deposit were “gigantic, remarkable, flawless and immense.” Boosters proclaimed, “The marble age is here.” Obviously, dreams were big for Marble.

Jan 1, 2003

By David van Cleave, David L. Rome

Whether you buy your minicomputer from a manufacturer or another vendor, the first thing you must do is define your needs. With good planning, the initial cost will be low and your return on investment will be maximized over the long term. Involving all members of your staff who will he using the new computer in the planning phase is also important. Their participation will alleviate any potential concerns they may have about new equipment, and their suggestions will provide valuable input for your specifications. After you define your proposed system, survey available hardware and software. The survey will help you in the next step, preparation of specifications. The specifications, along with a quote request, are then sent to various manufacturers. Consider the Manufacturer When selecting your minicomputer, one important item to consider is the manufacturer. Remember, when you buy a computer, you're also buying the services of a computer company. A firm that makes a commitment to its customers and provides a product that is field tested before releasing it for sale is preferable. Examine the company's maintenance and support packages, since every machine requires preventive maintenance. Does your manufacturer or original equipment manufacturer (OEM) support service sites in your area? Has their service record been commendable? Will they provide training for your personnel and a supply of circuit boards so you can retain a degree of self-service autonomy? Three methods of buying a computer involve the manufacturer, an OEM, and the systems house. Buying direct from the manufacturer means you go straight to the source, using no middleman. This gives you maximum flexibility; you can consider every alternative and many possible combinations of computers, peripherals, and software until you find exactly the right system for you. The OEM buys computers direct from the manufacturer and builds them into his own computerized, special purpose product. He usually sells a complete package, including software and hardware, and often noncompetitive equipment as well (a scientific or engineering instrument, for example), designed for the mining market. Because he offers a packaged product, the OEM can often charge less for the system than if you put the pieces together yourself. In many ways, the OEM also provides a unique system. And while the OEM sells a packaged solution, he also usually has the special market knowledge necessary to modify the system to meet your unique needs, if necessary.

Jan 11, 1981

By E. P. Hayes

This report supplements the date contained in Bureau of Mines Information Circular 6156, "Special features of core drilling in the salt beds of Western Texas and New Mexico," by J. S. Wroth. That circular dealt with the drilling of the first 12 of the 24 potash tests made by the U. S. Bureau of Mines in cooperation with the U. S. Geological Survey; this report is concerned with the drilling of the last 12 tests. ACKNOWLEDGMENTS The writer is indebted to R. E. Heithecker, the Bureau of Mines engineer who had charge of the drilling of tests 13 to 17, for his well-prepared records on the drilling of these tests.

Jan 1, 1933

The Bulli and Wongawilli Seams, the two principal sources of coking coal for the Port Kembla steelworks of Australian Iron & Steel Pty. Ltd., vary in rank and in type over the Southern and South Western Coalfields.The Bulli Seam, ranging widely in type, produces coke varying from weak to strong. The Wongawilli Seam, more consistent in type, produces coke of more consistent strength, but considerably less strong than that from the best Bulli Seam coal.Plans of seam variation show the regional trends in rank and type for each seam.The strongest coke is derived from coal containing between 45 and 55 per cent vitrinite, m.m.f. This is obtainable from the Bulli Seam in a zone embracing Bulli and Appin collieries.A satisfactory correlation is achieved between vitrinite content and coke stability and hardness, enabling prediction of coke strength for Southern Coalfield coals.The use of vitrinite reflectance, as an indicator of rank, in addition to type to predict coke strengths is at present hampered by lack of data, particularly in the South Western Coalfield. Nevertheless, data available at present allow the use of both variables and give better correlations with coke strengths than type alone.A spread of comprehensive data across both coalfields will enable advance assessment of cokes produced from coals having known rank and type. Blending to a ranktype specification for optimum coke strengths would allow the best use of the coal reserves of the coalfields.

Jan 1, 1969