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By R. A. Pallanch

Sodium sulfite as a zinc retarding agent in the selective Hotation of complex lead-zinc sulfide ores was discovered by the writer in the summer of 1919 in the testing laboratory of the U. S. Smelting, Refining & Mining Co.'s gravity concentrator at Midvalc. Utah. It proved to be the first reagent to give consistently good results in the laboratory on the cornpanj's Bingham ore. In December, 1919, C. A Lemke, concentrator superintendent, recommended that a flotation unit be added to the existing gravity mill to handle the mill slimes, using sodium sulfite as the zinc depressant Owing to the poor lead and zinc markets and the unfavorable royalty schedules offered by the Minerals Separation Co., the project fell through at this time. In 1921, a number of laboratory tests were made at Midvale. on other ores, among them ore from the Sunnyside mine at Eureka, Chlo. Both sodium and calcium sulfites were used with succcss on this ore. Early in 1923, further tests were made at Eureka, shortly after the Sunnyside company had resumed operations after a two-year shutdown. AS a consequence sodium sulfite was given a trial in the mill. The results showcd sufficient improvement over previous work as to warrant continuous use of this reagent in the lead circuit Exeept for a week or so in 1926 and for several weeks in April, 1927, when sodium cyanide and zinc sulfate were given trial runs in this mill. sodium sulfite has been used ever sinee.. Sodium sulfite was chosen rather than the calcim sulfite brcauscl of its gre1ater sollubility, making it possitdr. to introduee the reagent as a solutiun. This Solution is introdueed into the Marry ball mills along with the original feed of ore,. The consumption of sodium sulfite in the Sunnyside mill varies from 1/4 to 12 lb per ton of ore, the smaller amount probably being nearer the average. In February, 1924, laboratory work at Midvale demonstratcd conclusivcly that good results could be obtaincd on the company's Bingham ore and on most of the custom ores tested by using sodiuin sulfite as the zinc depressant, xanthate as the lead enhancer in the lcad circuit, followed by copper sulfate and additional xanthate to float the zinc Sodium sulfide was used to float the iron pyrite after the lead and

Jan 1, 1928

By K. G. F. Janssens

In the process of annealing a deformed metal the microstructure changes due to concurrent recrystallization, grain growth and precipitation. It is common knowledge that all three of these microstructural transformations show a strong dependence on each other, and that an overall model must take the relevant interactions into account. Aiming at the development of an approach which is useful in the more general case, a computational model is being developed which allows the prediction of the three dimensional grain topology and orientation distribution function of any metal submitted to subsequent deformation and annealing, taking into account concurrent recrystallization, grain growth and precipitation and starting from a statistical representation of the deformed microstructure. In this contribution a case study is presented which illustrates the potential and limits of the state of the art in the field. Keywords: Microstructure Evolution Modeling, Irregular Cellular Automata, Deformation, Precipitation, Recrystallization, Grain Growth

Jan 1, 2003

Geophysical anomalies result from the passage of hydrothermal fluids through rocks. Interpretation of these anomalies, when integrated with available geological and geochemical data, assists the construction of a conceptual model of the original hydrology of the system. The original extent of a geothermal system is often indicated by the distribution of low resistivity argillic clay alteration. Quartz-adularia vein deposits, silica sinters or stockwork (often mineralised) cause local increases in resistivity. Appropriately chosen electrical techniques can therefore be used to help target such structures. Airborne magnetic surveys have also proven useful in New Zealand epithermal exploration, because hydrothermal fluids destroy magnetite causing extensive demagnetisation anomalies. Ground magnetic surveys can sometimes be useful for geological interpretation on a local scale. Positive gravity anomalies may occur as a result of mineral precipitation (silica or calcite) in high porosity host rocks, while negative gravity anomalies can result from hydrothermal fracturing and leaching of relatively dense host rocks. The relative merits of these geophysical techniques as used in the exploration of epithermal mineral prospects are discussed, with particular reference to the Hauraki Goldfield. The preferred method for defining zones of quartz veining/silicification is vector or tensor gradient resistivity. Exploration strategies and technique refinements are suggested as a means of improving the resolution of potentially mineralised target structures, in a more efficient and cost effective manner.

Jan 1, 1993

By L. F. Engle, M. A. Hewedi

SUMMARY Initial interest in using solutions of ammonium salts to leach native copper was documented in notes from an AIME meeting in 1871; By 1916-1917, application of the NH3-CO2-H2O system to recover nonferrous metals attained commercial significance, when it was used as a process for copper recovery by Kennecott Copper Corporation and Calumet & Hecla Mining Company. The Caron work in the early 1920s, Freeport Sulphur Company’s achievements leaching Cuban laterites during World War II, out- standing accomplishments in both eastern and western Canada, recovery of manganese related to the work of Dean -- all serve as landmarks as this One Century Review surveys a base for future technology. Current emphasis on compatibility of metals-producing systems with the need to meet environmental protection criteria provides special encouragement to researchers and engineers to find accept- able ways of recovering metals. The ever-present demand of management to design, build and operate facilities on a profitable basis provides additional impetus to apply information from the technical literature to that need. Examination of the general approach to this paper will reveal much that is firm and positive with respect to empirical results -- extractions, recoveries, amenability to familiar proven equipment and materials of construction common to the industry. Although there are many references, there are gaps in the basic scientific data that if filled could lead to even more usefulness; the paper attempts to indicate where further information is needed.

Jan 1, 1973

By Albert J. McIntosh

With petroleum consumption declining temporarily after V-J day, the oil industry is urged to use this period as a kind of stopgap to rebuild its war-depleted inventories and help cushion the effect of this decline on producers and refiners. Higher inventories should be reestablished, since recent experiences have indicated that, by and large, the present inventories of crude oil are too low even with the tremendous current production available. The following analysis indicates that inventory levels could be built up to about 490,000,000 bbl. by the end of 1947, an increase of about 40,000,000 bbl. over the reported stock estimated for the war's end. If at the end of the war the military have some 20,000,000 bbl. on hand, this inventory will either be resold to the industry or certain demands that have been assumed to be met by industry will be supplied out of these military stocks, which would leave about 20,000,000 bbl. (net) to be built up from current production. For stock rebuilding the industry could use 10,000,000 bbl. of crude plus 10,00,000 bbl. of products, totaling 20,000,000 bbl. If this were spread over a year, this would mean 55,000 bbl. a day. By analyzing the average inventories held in a year with the total quantity of goods handled during the year, the following study and tables indicate how far the inventories should increase in the immediate postwar period. Introduction For the period immediately following V-J day, most of the petroleum economists have forecast a considerable decline in the total consumption of petroleum and its products in the United States. This will be caused by the elimination of most of the military demands and the inability of civilians to immediately replace automobiles, burners, etc., and thus increase their requirements to make up for the military decline. When the automobile industry has been back on full production for two or three years, civilians will be able to consume much larger quantities of gasoline. Delay in the manufacture of new oil burners and the time it takes to construct new homes, adds up to the same story for distillate fuels. In reviewing this outlook, the question has arisen whether the petroleum industry should not use this period of lower consumption as a kind of stopgap to rebuild its war-depleted inveritories and help cushion the effect on producers and refiners of this sudden drop in requirements. Some persons have indicated that hundreds of thousands of barrels a day could be used for this purpose extending over a year or more. Refineries will be in existence, which could run over 5,000,000 bbl. of crude oil a day and crude-oil production might be running 600,000 to 700,000 bbl. a day above the demands now forecast for the period after V-J day. Reasons for. Making Inventories In order to plan intelligently for this period, the petroleum industry should determine the needs for the establishment of higher inventories for crude and petroleum products than have been carried during the war. The reasons for trying to make such a determination are as follows:

Jan 1, 1945

The production of metallic titanium and titanium-rich alloys in forms useful to the engineer involves the use of certain techniques not usually necessary in fabricating the commoner metals and alloys. However, not all stages in the handling and shaping of titanium-base materials require the application of unfamiliar methods. It is the purpose of this paper to indicate where the well-known techniques are applicable as well as to outline the unusual operations which are necessitated by certain chemical characteristics of titanium.In brief, the characteristics just mentioned are manifestations of the very great reactivity of titanium, especially at elevated temperatures. Liquid titanium burns vigorously when brought into contact with air. It also reacts with practically all refractories, causing damage to the latter as well as undesirable contamination of the metal. Even solid titanium undergoes serious superficial contamination when heated above 800°C. in air for more than a few minutes. In addition to an oxide skin being formed, oxygen enters into solid solution in the surface of the metal causing the latter to become hardened and eventually embrittled.Up to date, titanium has been made only on a pilot plant scale by methods which produce a spongy or powdered product. Refractory problems have prevented the development of chemical reduction methods for making titanium in the form of a liquid pool from which ingots of useful size could be cast. Therefore the first part of this paper will cover the consolidation of powdered or spongy titanium. The latter portion will provide a brief description of...

Jan 1, 1950

By T. M. Chance

THE first bituminous coal cleaning-plant to use the sand-flotation process1 was placed in operation on Oct. 1, 1925, at the tipple of the East Broad Top Railroad & Coal Co., at Mt. Union, Pa. The general principles governing the design of plants of this type and typical operating results of anthracite sand-flotation units have been previously outlined.2 I will, therefore, confine myself to a description of this particular plant and to some of the elements of design it incorporates. THE ORIGINAL MT. UNION TIPPLE The plant was installed to transfer coal from steel narrow-gage cars of 60,000 and 70,000 lbs. capacity to standard-gage equipment. The coal was hauled some 30 miles from the East Broad Top field. This coal, mined by the Rockhill Coal & Iron Co. and other operators, is a low-volatile slow-coking coal with- ash of high-fusion point. It is normally a high-grade coal that does not contain an excessive amount of free impurities, but it requires careful handling to secure a fair domestic yield, and, naturally, the need for narrow-gage transshipment increases the difficulty of the problem. The narrow-gage cars were discharged into an 8-car track hopper equipped with two feeders passing the coal to two 42-in. apron intake conveyors. Twin units were installed throughout in this original plant, two lump-and-egg shaking screens, two lump picking-tables, two egg picking-tables and two stoker conveyors. The stoker coal was loaded without cleaning. The loading tracks and booms were in duplicate and with the layout as originally installed either unit could be run independently, each unit shipping a different class of coal or both units making the same product.

Jan 2, 1926

By C. E. Baltzer

This paper highlights the position of coal supply in regard to the requirements for electric-utility operations. The text and the appended tables outline the trend of thermal power development and fuel use in the electric-utility industry. Mention is made of several argumentative factors influencing the use of coal in relation to competitive oil and gas, and of the importance attached to developing a realistic understanding of the respective problems faced by the supplier and consumer of coal. * * * TREND OF" THERMAL POWER DEVELOPMENT T HE RATE OF ADVANCE in thermal power has been significant during recent years, particularly in the Atlantic Provinces, the Prairie Provinces, Ontario, and British Columbia. While dependence on thermal power in Quebec and the Northern Territories is less than in the remainder of Canada, these regions also eventually will have need for increased amounts of such power.

Jan 1, 1961

By E. Kusaka, M. EL Salmawy

"The electrokinetic behavior of EL Maghara coal has been investigated in the presence of nonyl and octyl nonionic surfactants containing polyethoxy of different sizes with trade names of Triton-X100 (TX-100), Triton-X 705 (TX-705), Triton WR-1339 (TWR-1339) and Brij 58. The electrokinetic behavior was determined by zeta potential measurements. Zeta potential measurements were conducted by Laser-Doppler electrophoresis technique using zetamaster. The results show that the zeta potential of Egyptian coal varies with pH value, the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. It was found that the polymeric surfactants reduce the negative values of zeta potential of coal. The shift of PZC of coal upon deashing appears to be closely relevant to silicate mineral removal."

Jan 1, 2014

By Robert H. Palmer

Sacuranao Field.—Bacuranao field is about 12 miles east of Havana, along the contact between Cretaceous sediments and a serpentine intrusion. The zone lies within an extensive anticlinorium. The field had no developments during the year 1939. The production of 9½ bbl. per day is distilled and the gasoline and kerosene are extracted. The asphalt residue. is sold for road construction. The gas is compressed and

Jan 1, 1940

By J. H. Brophy, S. J. Michalik

A constitution diagram for the system Mo-Ir has been determined. The maximum solubility of iridium in molybdenum is 16 at. pct at 2110ºC and decreases to less than 5 at. pct at 1500°C. The solubility of molybdenum in iridium is 22 at. pct. Three intermediate phases appear in the system: 8 MoJr, having the p-tungsten structure; a phase, a cornplex tetragonal structure; and the hcp ? phase. Metallography, melting point determinations, X-ray diffraction and fluorescence, and electron micro-probe unalyses were employed in establishing the diagram. PREVIOUS to the present investigation, the intermediate phases in the Mo-Ir system were identified, but no detailed account of the phase diagram has been reported in the literature. Raub1 investigated alloys of Mo-Ir over an extensive range of composition between the temperatures of 800º and 1600°C. The in-termetallic compound MosIr was found to exist with nearly pure molybdenum, as the solubility of iridium in molybdenum was not detectable parametrically in this temperature range. MO3Ir was found to be iso-morphic with a ß-tungsten type structure, having a parameter of 4.959Å. An intermediate hcp phase, designated as the ? phase, ranged in composition from 52 to 78.5 at. pct at 800ºC, and from 41 to 78.5 at. pct Ir at 1200°C. Parameters noted for the ? phase were as follows: at 42.7 at. pct Ir, a = 2.771i0, c = 4.4366, c/a = 1.601; at 78.5 at. pct Ir, a = 2.736A, c = 4.378A, c/a = 1.600. Molybdenum was found to be soluble in iridium up to 16.5 at. pct Mo (83.5 at. pct Irj, with the parameter of iridium increasing to 3.845A at the solubility limit. Knapton,2 who investigated alloys between 15 and 85 at. pct Ir, essentially agreed with Raub's data, but, in addition, found a a phase in as-melted alloys near 25 at. pcto Ir. The oaphase lattice parameters were a = 9.64Å, c = 4.96Å, c/a = 0.515. The a phase was replaced by the 8 -tungsten phase on annealing at 1600°C. Knapton concluded that the a was stable only at elevated temperatures, and placed the composition of the a phase at approximately 30 at. pct Ir. The intermetallic compound Mo3Ir, with a lattice parameter of 4.965A, was included among the 8-tungsten structures reported by ~eller.' Matthias and Corenzwit,4 and Bucke15 studied the superconducting nature of MosIr, and reported a superconducting transition temperature of 8.$K. The present investigation describes the phase relationships in the Mo-Ir alloy system determined by melting point measurements, X-ray diffraction and fluorescence, and metallography. EXPERIMENTAL PROCEDURES Alloys for the determination of the phase diagram were prepared from powders. Commercial 99.9 pct Mo from Fansteel Metallurgical Corp. and 99.9 pct Ir powder from J. Bishop and Co. Platinum Works were used. The powders were weighed to nominal compositions, mixed, and then pressed, without binder, into compacts weighing 4 to 6 g. These were presintered in uacuo between 1200' and 1400°C for 1 hr, to reduce the degree of spattering during subsequent arc-melting. The compacts were arc-melted in a nonconsumable tungsten electrode furnace six times on alternate sides on a water-cooled copper hearth in an atmosphere of zirconium-getter ed argon at 500 mm of mercury pressure. In almost all cases, this procedure yielded buttons of satisfactory homogeneity. The composition of all melted buttons were confirmed by X-ray fluorescent analysis using the experimentally determined ratio of the iridium La1 line intensity to that of the molybdenum Ka1 line as a function of composition. In this determination four alloys analyzed by wet chemical methods were used as standards. An uncertainty range of ±1 at. pct has been attributed to all indicated compositions. All heat treatments and solidus measurements were carried out in tantalum resistance heating elements in vacuum conditions of 10-4 to 10-5 mm of mercury. A detailed account of this procedure has been reported by Schwarzkopf and Brophy.8 In the heat treatment and solidus measurements of iridium-rich alloys (50 at. pct Ir or greater), a tungsten lining was inserted into the tantalum resistance heating element because of a eutectic reaction which occurs between iridium and tantalum at 1948ºc.7 Heat treatments and solidus measurements carried out at compositions less than 40 at. pct Ir both with and without tungsten linings within the resistance

Jan 1, 1963

By Neil B. Young

Carbonate minerals constitute a major fraction of the oil shale in Colorado's Green River Formation. Quantification of carbonate minerals is important for the characterization of oil shale, particularly because of their thermal activity in production of oil from shale. The carbonate minerals found in this oil shale are nahcolite (NaHCO3), dawsonite [NaA1(OH)2CO3], dolomite [(Mg1-xFx)Ca(CO3)2], calcite (CaCO3), and ferroan [(Mg1-xFex)CO3]. Although carbonate minerals can be removed by acid extraction from the balance of the oil shale, direct determination of carbonate minerals is complicated by the occurrence of the same cations in more than one mineral. A method for assigning the acid-soluble cations to the individual carbonate minerals was developed from two assumptions based on oil shale geochemistry: (1) Calcite and ferroan do not occur together, and (2) the ratio of iron and magnesium is the same in dolomite and ferroan. These assumptions were tested by the Bureau of Mines by applying the technique for assigning cations to 219 samples from the saline section of the formation. The reported carbonate mineral amounts were compared statistically with X-ray diffraction peak heights, verifying the cation assignment method.

Jan 1, 1975

Jan 1, 1884

By P. R. Taylor

The ability to process complex precious metal sulfide concentrates containing antimony and arsenic, in an economic and environmentally safe manner, is an important problem facing the mining industry in the united states. Preliminary experiments have been performed to evaluate the possibility of treating a complex sulfide concentrate to recover antimony and precious metals while fixing the arsenic and sulfur as calcium arsenate and calcium sulfate. The process involves the oxidation of the antimony and arsenic minerals in the presence of soda ash (to collect the sulfur dioxide and to keep the antimony and arsenic from forming volatile compounds), the selective leaching of the arsenic from the roast calcine with a heated caustic solution, the precipitation of the arsenic and sulfate with calcium hydroxide and/or calcium chloride, the reduction of the residual antimony (collecting the precious metals), fuming of the metal to form a marketable antimony oxide, and crucible reduction of the residue to obtain a gold and silver dore. Experiments have been performed to evaluate the first stage of this process. Batch experiments were performed using synthetic concentrates of stibnite and arsenopyrite. Variables that were studied included: mixture weight fractions, temperature, gas flow rate, oxygen partial pressure and time. All of the off gas dust and sulfur containing gases were collected and analyzed. The roast solid residue was subjected to arsenic leach tests and the leach solutions were subjected to arsenic and sulfate precipitation tests.

Jan 1, 1993

By G. Vibert Douglas

It has long been recognized that there are considerable difficulties connected with the physical and chemical explanation of shoots of ore. The literature of Mining Geology has frequent references to this subject; but the reasons given for the actual location of primary ore-shoots have been very tentative. In practice, the geologist or miner depends to a great extent on sampling and assaying to determine the boundaries of profitable ore within the mineralized zone. An ore-shoot is a portion of a mineralized zone which has a sufficient concentration of valuable minerals to make it ore. Ore deposits have been classified according to many schemes. There are classifications based on morphology and on genesis. However, it is also possible to classify hypo-gene hydrothermal ore-bodies in terms of ore-shoots or vice versa. A.-Ore-deposits in which the whole of the mineralized zone is ore, which is the same as saying that the ore-shoot extends throughout the mineralized zone. An example of this type of deposit would be the pyritic mineralization of Rio Tinto. B.-The second type would comprise those deposits in which the ore-shoots bear some relation to the geological structure of the area: all deposits in which 'bonanzas' occur in folds in the zone, at the intersection of veins along certain fault (or joint) features and other such controls. There are a great many examples of this type: (a) The Rhodesian copper lodes, where Bancroft and Gray have pointed out the association of the shoots of ore with drag folds. (b) A similar association has been pointed out by Faribault for some of the gold veins of Nova Scotia, e.g., Mount Uniacke. (c) The great bonanza of the Comstock lode in Nevada. C.-Deposits in which the localization of ore has been effected by the chemical character of the wall-rock. Examples of this type are the Fahlbands of Scandinavia, and the 'indicator' deposits of Ballarat, Australia. D.-Lastly, deposits in which there is apparently no structural and no chemical control.

Jan 1, 1934

By Jean-Jacques Prompsy, J. S. Rinehart

The purpose of the present study was to arrive at a better understanding of the stress fields developed within drill bits under dynamic loading and the influence that these stress fields could have on the failure of the drill bits. Particular emphasis has been given to the influence that bit shape has on the establishment of highly localized, potentially destructive stress inhomogeneities within the bit. This paper covers one phase of a broad study involving three velocity regimes: impacts at very low velocities, 0 to 20 ft/sec, a velocity range in which dynamic effects are just beginning to be found; impacts at velocities ranging from 20 to several hundred ft/sec, arange commonly encountered in practical drilling operations; and impulsive loading through the detonation of explosives, a velocity range in which the dynamic effects are greatly exaggerated and made more identifiable. Specifically, fracturing which develops at the end of a cylindrical bar undergoing a shock produced by impact was experimentally investigated, the impacted area being the face of a truncated cone terminating the cylindrical bar. Fracture characteristics were looked at as a function of impact velocity, area of impacted face and cone angle — parameters of considerable importance in the design of drill bit. EXPERIMENTS The specimens were made of Plexiglas, which enabled the fracture pattern to be easily observed. In Plexiglas, the velocity of a longitudinal wave is about 8,700 ft/sec, and the velocity of the transverse wave about 4,200 ft/sec. The specimens were impacted by a steel cylinder whose lower face was parallel to the terminal face of the experimental bit, as shown in Fig. 1. The impacting mass was shifted up and down on two steel rods, dropping from a maximum height of 11 ft, with the velocity varied between 0 and 6.5 m/sec. The initial mass of the cylinder was 4.1 kg, which could be increased by steps up to 8.8 kg by addition of steel plates. The velocity of the steel cylinder was determined by using an electric circuit; as the cylinder dropped, it contacted two steel wires, the first one starting and the second one stopping an electronic counter. Two similar counters connected in parallel were used to corroborate each other. The velocity was checked at each drop as it had been observed to vary somewhat from drop to drop. The two contact wires were located just above the top of the specimen so as to give a value of the instantaneous velocity of the steel cylinder at impact. The distance between the wires was 40 ± 0.5 mm and the discrepancy between the counters was never more than 0.1 m/sec. Thus the velocity was known to within 3.25 per cent. This precision was sufficient with respect to the precision of the machining of the specimens. A very small lack of parallelism between the face of a specimen and that of the impacting hammer resulted in an oblique impact which required a much lower velocity to break the specimen. The experiments had a twofold purpose — (1) to observe the fracture pattern, and (2) to find relationships between the minimum velocity required to generate a fracture within a specimen and the

By Wayne F. Crockett, Martin H. Col

Gold, as a precious metal, has been sought for several thousand years. During this time economics have generally determined whether or not a deposit is minable. Today, few would spend $500.00 or $1,000.00 to produce one ounce of gold, yet most gold deposits currently being mined would have such costs if they were mined using the methods of the 18th century. Innovation has been the key to success in the world of mining. We are constantly having to look for new ways to mine deposits of lower grade, at greater depths, or with higher stripping ratios. The mining of placer gold deposits has always been subject to the volatile swings of the world price and the constant rise in production costs. The rise in costs is compounded by the drop in overall ore grades. Occasionally, a major technological innovation will dramatically reduce the costs of placer mining to allow previously marginal or unminable deposits to be mined at a profit. The continuous bucketline dredge was the last such major innovation in the gold placer mining. The continuous bucketline dredge has allowed large volumes of placer deposits to be picked up and processed on a continuous basis. Unfortunately, as the overall grade of the deposit declines, it becomes impossible to process enough ore to pay for the operating costs. There are many gold deposits around the world waiting for the next technological innovation that will allow them to be mined. One such deposit has been the Grey River deposit near Greymouth in New Zealand. The deposit contains gold reserves of 8992 kg, yet the deposit has been sitting idle for many years because the average value

Jan 1, 1988

By N. Brown, J. Washburn, E. R. Parker

MOST previous quantitative work on creep of single crystals has been concerned primarily with developing empirical equations for the creep curve. Although the equations used by Cottrell and Aytekin¹ and Tyndall² represented the data quite well, it was often necessary to use different values of the constants for different specimens even though they were apparently tested under identical conditions. In the course of previous work on the effect of surface coatings on creep of zinc single crystals," it was found that equal resolved shear stress frequently did not produce equal creep rates in different specimens. The work of Chalmers' in the very

Jan 1, 1954

By F. S. Karn

Measurements were made of the flow of helium, methane, ethane, butane, and toluene through thin disks of coal. All measurements were made on a dense layer in the Pittsburgh seam identified as attritus. Flow increased with pressure differential and temperature. At room temperature and a pressure differential of 1 atmosphere flow rates along the bedding plane of Pittsburgh seam coal were helium 881 X 10-10 cm2 sec-1, methane 1.2 X 10 -10 cm2 sec-1, ethane 0.54 X 10-10 cm 2 sec-1, n-butane 0.35 X 10-10 cm2sec-1, and toluene 3.8 X 10-10 cm2sec-1. Flow rates were 50 percent lower across the bedding plane of the coal than along the bedding plane. Activation energies were 3.9 kcal mole-1 for helium and 13.6 kcal mole-1 for methane, with diffusion measured either along or across the bedding plane.

Jan 1, 1970

By S. K. Mishra

Introduction The history of the Australian coal industry is almost as old as the history of Australia after new settlement. The first cargo of coal was exported from Newcastle to India in 1799. Coal has been mined in Australia for almost two centuries. But there are indications that the first coal was processed in 1877 in the Newcastle area. This is nearly 50 years after the first coal processing in Europe. Processing on any significant scale began in 1944 at the Newcastle Steel Works. In Queensland, however, coal processing did not begin until the second quarter of this century. The dramatic growth of mining and processing of Australian coal since the mid-60s is primarily due to the expansion of the export market in Japan, Asia, and Europe. Australian coals Black coal occurs in most of the major sedimentary basins of Australia. The better known deposits of commercial importance are in the Sydney, Bowen, Oakland, and Gailiee Basins. Apart from the Collie Basin in western Australia, other coal deposits of the Arckinga Basin in South Australia, the Bonaparte Basin in Northern Territory, and the Tasmania Basin are basically unexploited. The Sydney Basin of New South Wales and Bowen Basin of Queensland remain the major producers of black coal in Australia. Currently exploited or potentially commercial deposits of black coal in Australia occur in strata ranging in age from Permian to Tertiary. Estimated black coal reserves are summarized in Table 1. Coals from different ages have significant differences in their petrographic characteristics. Many of the Permian coals are usually rich in inertinite. Jurassic and Tertiary coals are typically rich in vitrinite content. Typical petrographic and chemical characteristics of some important Australian coking coals are summarized in Tables 2 and 3. The reserves of coking coals are restricted in the main to the Permian coals of the Sydney and Bowen Basins. Coal deposits in the latter are at shallow depth. A high percentage of these are being strip-mined. On the other hand, in the Sydney Basin, the majority of the reserves of good quality coking coals are at significant depth. The mining cost of these deposits is substantially higher than those in the Bowen Basin. It is usually possible to make strong coke with Australian Permian coals of vitrinite content much lower than the other international coals. But there are many major Permian deposits in Australia where low vitrinite content presents problems. As they are classified as marginal coking coals, optimization of their pro¬cessing plays an important role in meeting the market specifications of coking coal. The major reason for processing Australian coal is to reduce the ash content. Compared with British and some American coals, Australian coals are of relatively high ash content. Unlike American coals, more than 99% of the Australian coal deposits have sulfur content less than 1%. Consequently, sulfur control has never been a major problem. The coking quality of coal is improved simply through the ash reduction in the marketable product. However, with the increase in intensive mechanization and multi-stage handling of coal be-

Jan 9, 1985