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By F. W. Gray

A GEOLOGICAL study seeking to determine, for economic purposes, the value of the Sydney coalfield as a source of coal supply. Limitations of the coalfield come under two main heads: (a) Areal extent of the undersea coalfield. (b) The distance from shore at which coal can be mined at a cost of production permitting its profitable sale. Conclusions reached are that the areal extent of seams below the Phalen seam is of. small economic importance, and that non-persistence of these seams in full thickness and quality in the undersea extension of the coalfield will put an end to profitable mining before any limitations connected with distance from the shore-line become operative. With respect to the Phalen seam, non-persistence or deterioration of the seam will become effective in the western part of the coalfield, and less certainly in the eastern part of the coalfield, before operation of limitations by distance from shore. In the central portion of the coalfield, the seam probably persists in commercially workable thickness and quality to beyond the limit of mining set by distance from the shore-line. With respect to the seams above the Phalen seam between the Mountain fault on the extreme western boundary of the coalfield and the assumed termination of the deposition area on the eastern extremity of the field near South Head of Morien, there appear to be only such limitations as arise from engineering approach, distance from shore, sufficiency of strata cover between the sea-floor and the upper coal seams, and quality of the coal (with certain reservations as to the continuity of the upper seams under Sydney harbour and in the Sydney Mines-Little Bras d'Or district). Some of these seams have fragmentary land outcroppings from which their persistence seaward is assumed, and there may be other and still higher seams in the strata column which are entirely submarine.

Jan 1, 1941

By G. W. Mannard

The large massive sulphide deposits present a formidable challenge to the economic geologist. They represent such huge concentrations of iron, sulphur, base metals and precious metals that it is difficult to conceive how they were derived from the crust or mantle of the Earth. The problem of the origin of massive sulphide deposits has generated a geological controversy which has lasted two hundred years and shows no sign of abating. The economic incentive to solve this problem is great, as the massive sulphide bodies are the moat important source of the world's zinc, lead, and silver, as well as yielding large amounts of copper and gold. Using the criteria of abundance, size, age distribution and gross value of contained metals, the predominant sub-group of the massive sulphide deposits is that which comprises the crudely conformable pyritic (or pyrrhotitic) deposits which occur in stratified volcanic and sedimentary rocks or their metamorphosed equivalents. Examples of this sub-group are: the Buchans, Bathurst, Noranda, Kidd Creek, Flin Plon and Sullivan deposits of Canada; the Mt. Isa and Broken Hill orebodies of Australia; the Cyprus, Rio Tinto, Meggen and Rammelsberg deposits of Europe; Ducktown and the United Verde in United States; and the Kuroko deposits of Japan.

Jan 1, 1973

By J, J M. Young, P T. Nielsen, R Zhu

Improved understanding of the variables that influence hydrocyclone performance is of increasing interest to the iron ore industry, where hydorcyclones are widely used to deslime fine ore. In many cases, the impact of particular variables is not quantified sufficiently well experimentally to ensure that industrial performance will match expectations. The current work focused on developing and implementing a systematic methodology to evaluate and compare the performance of four different hydrocyclones in a desliming application. A critical component of the project was the design and construction of a pilot-scale hydrocyclone rig using state of the art monitoring and sampling methods. A wide ranging test programme was conducted to quantify the effect on metallurgical performance of the key hydrocyclone variables such as pressure, feed density, vortex finder size, spigot size and hydrocyclone make/overall design. Details of the experimental approach are presented, along with a discussion of the sizing analysis methods used. Performance criteria were established to assess the four hydrocyclones. The effects of each major variable were quantified over a wide range of conditions. The results show that clear performance differentiation was achieved, enabling the selection of the optimum configuration. The results from this work demonstrate the benefit of objectively assessing the performance of nominally equivalent units in selecting an optimum configuration that best satisfies the performance criteria.

Jan 1, 2002

By R. A. Crouse

The Tanco pegmatite at Bernie Lake, in the Lac du Bonnet mining district of southeastern Manitoba, is a unique deposit of Li, Rb, Cs and Ta, with substantial reserves of Be and several industrial minerals. This paper summarizes the present state of understanding the regional geology, structural setting, zoning, mineralogy and geochemistry of the pegmatite, and the mining and ore-processing methods used in its exploitation.

Jan 1, 1979

By R. J. Hundermark, L. R. Nelson

"The critical importance of tap-hole design and management for furnace performance and longevity is explored through examining some of the specific matte, metal, and slag tapping requirements of non-ferrous copper blister and matte converting and smelting, ferroalloy smelting, and ironmaking systems. Process conditions and productivity requirements and their influence on tapping are reviewed for these different pyrometallurgical systems. Some critical aspects of the evolution of tap-hole design to meet the diverging process and tapping duties are examined. Differences and similarities in tapping practices and tap-hole management are reviewed. Finally, core aspects of tap-hole equipment and maintenance are identified – aspects that are considered important for securing improved tap-hole performance and life, so pivotal to superior furnace smelting performance. IntroductionThe sheer diversity of tapping configurations used on industrial pyrometallurgical operations is at first bewildering. They range from historical tilting furnaces without tapholes to modern eccentric bottom tapping (EBT) tilting and/or bottom slide-gate electric arc furnaces; to classical single tap-hole multiphase tapping (e.g. metal/matte and slag); to dedicated phase tap-holes (e.g. dedicated metal/matte-only and slag-only); to dedicated phase multiple tap-hole configurations (up to eight metal/matte-only tap-holes and six slag-only tap-holes); to more esoteric metal/matte-only siphons and slag overflow skimming, e.g. Mitsubishi Continuous Process (Matsutani, n.d.). This can be further complicated by periodic batch tapping; consecutive tapping on a given taphole; alternating tap-hole tapping practice; near-continuous slag-only tapping, with discrete batch matte/metal tapping on higher productivity, but low metal/matte fall (<20% by mass feed) Co and Ni ferroalloy and platinum group metal (PGM) matte furnaces; near-continuous tapping through batch tapping of individual tap-holes that are opened consecutively (Tanzil et al., 2001; Post et al., 2003); to fully continuous tapping on coupled multi-furnace cascades (Matsutani, n.d.)."

Jan 1, 2016

By Robert Bell

THE " Tar-Sands." is the name which has been given to the extensive horizontal deposit of fine Cretaceous sand, blackened by tarry petroleum, which forms the banks of the last or lowest 130 miles of the Athabasca river before it terminates in Athabasca lake. The Cretaceous strata, to which these sands belong, extend northwesterly from Dakota all the way to this lake and for 500 miles beyond it. The Athabasca river forms the uppermost section of the Athabasca-Mackenzie, one of the great rivers of the world. It rises on the Pacific side of the Rocky mountains, westward of Edmonton, and flows north of east to a point called Athabasca. Landing, 100 miles north of Edmonton, where it turns northward and runs about 280 miles before it falls into the west end of Athabasca lake. The section of this river-system which discharges the lake just named into Great Slave lake, is called Slave river, and below the latter lake it becomes the Mackenzie river. Along the section of 280 miles of the Athabasca river above mentioned, the Cretaceous strata consist of bluish-gray and drab-gray marls, on top, from Athabasca Landing to Drowned rapid, 110 miles down stream; then heavily bedded gray sandstones, 225 ft. in greatest thickness, underlying these, form the banks for about 40 miles further. The strata appear to be horizontal, but they really clip very slightly to the southward. At Drowned rapid, we see the first of the tar-sands resting on almost horizontal beds of bluish-gray limestone of Devonian age. In some places the limestone is associated with shaly or marly bands. Notwithstanding the great hiatus between the two series, the horizontal tar-sands lie conformably upon the almost level upper beds of the limestone wherever the two formations are seen together, all along the river, throughout a

Mar 1, 1908

By Louis, Jordan

THIS paper presents in an abbreviated form the chief points of interest in an investigation of the tarnish-resistant qualities of silver alloys, an investigation which has been carried out as a joint research by the Bureau of Mines and the Bureau of Standards and will later be reported in detail in an official publication from these bureaus. In 1923 a Commission of Gold and Silver Inquiry was created by a Resolution of the U. S. Senate to study the causes of the depressed condition of the gold and silver industry. In cooperation with this commission the Bureau of Mines made a preliminary survey to determine in what ways, if any, it might be possible to increase the uses of silver. One of the possibilities indicated by this survey was the development of silver alloys which should be non-tarnishing, or at least less-tarnishing, than the usual sterling silver (copper-silver). The preparation of a rather wide variety of silver alloys and the determination of their behavior under accelerated tarnish tests in the laboratory was therefore undertaken by the Bureau of Mines and Bureau of Standards as a joint investigation.

Jan 1, 1927

By Thompson IR

This paper describes a Client Consultant Relationship and shows how an engineering team created an environ- ment which fosters the development of good, economical and sometimes unique solutions. A major factor in establish- ing this environment was the Client&apos;s instruction to the Consultant to "propose solutions which, in the Consultant&apos;s considered opinion, best satisfy the needs of the project - not necessarily solutions which reproduce methods adopted elsewhere in the past." The Consultant&apos;s experience in other projects and disciplines outside mining has contributed by providing a cross- fertilisation of ideas. The team approach also allows the Client&apos;s expertise to be applied positively throughout the design process. These factors and the Client&apos;s foresight in providing adequate time for planning, allow the Client-Consultant Team to apply sound fundamental engineering in developing effective solutions.

Jan 1, 1975

By Robert C. Meaders

In this paper, autogenous grinding is defined as the combined crushing and grinder of a run-of-mine ore or the product from a primary crusher, in a single stage grinding mill. This is in contrast to pebble milling where pebbles are substituted for steel balls to grind a ball mill size feed. The autogenous mill to compete in efficiency with normal methods of crushing and grinding must not use greater power, must use less labor and steel, and must produce an equivalent product.

Jan 1, 1963

By Charles Hardy

?POWDER METALLURGY? is the production of semiformed or fully formed metal products by compressing metal powders. It had its beginnings in the fabrication of tungsten and molybdenum bars and wire by compression, sintering, and swaging. Powder metallurgy, although still in its infancy with other metals, has shown remarkable progress in recent years. Production of Metal Powders-The first step in any powder-metallurgy process is the production of metal particles of suitable shape and size. Mechanical processes for producing metal powders, as by crushing, stamping, or grinding, are usually not suitable, as the resulting particles may cause laminations and decreased strength in the finished articles. The principal metal powders now in use on a large scale are produced by electrolysis or by reduction of metal oxides by gases.

Jan 1, 1936

By N. E. Idenyi

The effects of compositions and firing temperatures on the physico-mechanical properties of blended Nsu fireclay and Nkalaha redbrick clay have been investigated. The clay samples were compounded according to the following ratios: 10:90, 20:80, 30:70, 40:60 50:50, 60:40, 70:30, 80:20 and 90:10 in the order Nsu: Nkalaha respectively, and test samples made and fired at 9000C, 10000C 11000C and 12000C. The properties tested for were the modulus of rupture, porosity, shrinkage, apparent density, water absorption and bulk density. From the results obtained, it is inferred that the blends have a maximum service temperature of 11000C, with the 30: 70 blend presenting the best characteristics. A conclusion is drawn to the effect that the blend could be adapted for the production of ceramic earthenware, electrical porcelain pin insulators, cement manufacture and for refractory linings where temperature requirements are less severe.

Jan 1, 2006

By C. Haycocks

The evolution of longwall mining is briefly traced from its inception in England in the 1620&apos;s. In the beginning this method recovered 90% of coal with roof closure controlled by packs and walls. Mechanization began with kerf cutting, crude face conveyors, and improved face support. Full face mining was accompanied by the introduction of self-advancing hydraulic supports. U.S. longwalls evolved a retreating system to recover blocks of coal outlined by room and pillar panels. Computer control combined with the most modern technology has greatly increased productivity. Past trends are used to predict future technological directions.

Jan 1, 1997

By M. E. Grimes

"The future of the uranium industry in Canada during the next twenty years will be very dependent on political and social issues on a world scale. Technology, as such, will tend to be of lesser importance. Nonetheless, some technical changes can be anticipated.This paper deals with milling of uranium ore, leaving further processing and nuclear power production to specialists in these fields. An attempt has been made to look at uranium production technology in Canada in relation to that in other countries, and to draw interference regarding future changes that seem probable in the Canadian context. In particular, recent advances in mill equipment are considered.The chemistry of uranium and its relatively low concentration in most ores has been responsible for a completely hydrometallurgical approach to mill processing, and this should continue. In spite of little commercial success to date, pre-concentration of lower grade ores will be researched further in order that these ores can compete with higher grade deposits in Canada.The discovery of the relatively high-grade ores of the Athabasksa region will undoubtedly influence choice of mill processes and equipment. The potential effect on innovations is discussed"

Jan 1, 1986

By Y. C. Liu

Ningxiang-type iron deposit is a most important sedimentary oolitic hematite deposit in China. Its? detected ore reserves are 3.72 billion tons, which is 73.5% of all detected reserves, and there are about 10 billion tons of prognostic resources. It is considered as the ?poor mine? for a long time be-cause of its difficult prooerty. But based on the ore characteristics of different deposits, the technological characteristics of ore are different with great diversity in ore baring horizon, distribution range, deposit scale, ore petrology, ore mineral assemblage and iron content. Through the study of deposit features and technological mineralogy of different Ningxiang-type of iron deposits in China, and based on industrial types and natural types of ore deposits, we divide different technological types according the technological features of the ore such as mineral composition, particle size, dissemination, occurrence of useful elements and harmful elements, the main physical and chemical properties of mineral and geological conditions of deposits, etc, moreover, propose the different utilization, mineral processing technologies and product schemes for the different types of ore.

Jan 1, 2014

By R. C. Emmett

The industrial practice of concentration of solids and production of clear solution by gravity sedimentation is an old technology. Through the years, many devices have been designed and built to aid this process. One of the more significant developments was a revolving rake mechanism to convey settled material to a central discharge point of a circular tank, patented in 1907(1). In recent years, clarification systems employing parallel inclined plates have appeared on the market; the original device utilizing this principle was patented in 1886(2). Numerous other methods have been invented, tested, discarded and sometimes re-invented, all with the specific intention of improving the capacity of a particular settling area. Sedimentation theory, as expressed in Stokes&apos; Law, shows that the rate of settling of a particle is directly proportional to the difference in density between the particle and the surrounding liquid and, more significantly, proportional to the square of the particle diameter. Anything that can increase the latter will greatly assist sedimentation and, as a result, flocculation always has been an integral part of sedimentation. Most materials suspended in aqueous media are naturally flocculent to some degree and, hence, are readily concentrated by sedimentation, although sometimes very slowly.

Jan 1, 1978

The major technological advances of the last 30 years have profoundly reshaped mining practices. Machines keep getting bigger while productivity continues to increase and manning levels drop. These trends will continue and the introduction of breakthrough technologies will continue to accelerate, driven by a continued focus on lowering the cost of production, improving the productivity of workers and machines, and ensuring safer working environments. At the same time, global consolidation of mining companies has impacted on technology development in a range of ways. There are many potential technologies being proposed, some already operating in Australian mines. The automation of underground load-haul-dump (LHD) trucks for example, continues the process of removing workers from the most dangerous operating environments. Global positioning systems fitted to draglines, fibre optic communication channels, and 400 tonne trucks are only some examples of what lies ahead. However, where we need to return focus is to the technology of management û which is also one of the two key interrelated themes of this keynote address. Have we, as an industry, adequately been able to keep up with technological advances? Are our management systems as competent as the machinery we employ? The other key theme is the processes of globalisation and consolidation. What are the impacts on our industry? What are the implications of these processes, particularly for the ways in which we manage our people? My paper is divided into several components:some comments on the coal industry and the dramatic restructuring we have seen in recent years; in the context of this restructuring, an overview of my company and its evolution; my views on the role of contractors; some comments on the consolidation also occurring in the mining machinery and equipment, technology and services sectors; some observations on two major areas of technology û drill and blast; and trucks, shovels and excavators; the implications of consolidation and new technology for our employees and management; and finally some comments on research programs.

Jan 1, 2001

The rush for alternate iron-units in the last few years spurred a true outbreak of new alternate iron units projects many of them incorporating new process in what can be classified as the.most fruitful and innovative technology outburst, in the steel industry, in decades In a recent paper we focused on what would be, in our opinion, the ultimate targets of the use of alternate iron-units by mini-mills: 1. to improve quality, 2. to reduce cost, 3. to increase plant productivity, and 4. to improve `supplyability&apos;. With these objectives in mind liquid hot-metal, among all possible scrap substitutes, has been proven to be by far the best. This conclusion stems from many different authors who have reviewed the `value in use&apos; of hot-metal against other alternate iron units and measured its impact on steel-shop productivity and cost (Figure 1).

Jan 1, 1999

By E. W. Williams

THE Ontario Research Foundation has developed a process for producing low-density steel shapes by direct reduction of iron oxide powders. The process is a combination of reduction, sintering (without compaction), and carburizing, and has been described by Cavanagh (1). Iron oxide powder, in the form of mill scale or highly concentrated iron ore, carefully sized, is poured into a porous mould. A reducing agent, generally coke breeze, is placed around this mould in a heat resistant sagger which is sealed off and heated to 2,000°F. for a number of hours. The coke/ ore ratio, the particle size distribution, the temperature and time of soaking, and the size and shape of the reduced product, determine the densities and carbon contents attained. The Defence Research Board sponsored a programme of research into some of the mechanical properties of the material (which was named Controlled Density Steel) and this paper is an account of various factors which govern the tensile strength of the steel. The ?practically attainable range of density is from 1.5 to 5.5 gm./ cc. but higher densities are obtained on hot working. This paper, however, is restricted to discussion of results for moulded products.

Jan 1, 1957

By S. K. Kawatra

Outokumpu Electronics has designed a new on-line coal slurry ash analyzer, based on an instrument developed at Michigan Technological University. The primary goal was to build an accurate instrument at the lowest possible cost. The instrument determines ash content from measurements of x-ray backscatter, iron Ka fluorescence, and low-energy y-ray absorption. It is capable of measuring the ash content with a standard error of 1.1% ash over an analysis range of 9-21% ash and 7-22% solids. The analyzer was tested on coals from United States, Poland, Great Britain and the USSR.

Jan 1, 1992

The process of electrostatic separation was developed in the late 19th century, but did not make much headway for about 25 years. High dc voltages, of the order of 20 kilovolts, are involved, and the only means of obtaining such voltages at that time were by the use of frictional machines, such as the Wimshurst. These were not reliable, for two reasons:-a. If a spark discharge occurred it took an appreciable time before a steady voltage was again attained.b. In damp weather the machines were almost useless.In the first 20 years of the 20th century the advent of mechanical and vacuum-tube rectifiers led to promising developments of &apos;the process. In the early 1920&apos;s flotation became widely used commercially, and proved to be more reliable, and capable of wider application, than electrostatic separation. During the last 15 years or so, with a better knowledge of the fundamentals forming the basis of the process, electrostatic separation is beginning to compete with flotation, especially in the treatment of smallsizedgranular material, such as beach sands. Electrostatic separation can be, and is, widely used in many cases where flotation is impossible, such as in the cleaning of food products which must be kept dry.

Jan 1, 1950