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By Benoit Clermont, Jan Lux

"Magotteaux and Anglo Platinum started a co-operation program with the main aim of establishing the optimum milling configuration measured in terms of throughput, fineness and energy consumption.For this purpose, a fully instrumented pilot milling plant, supplied by Magotteaux (Pty) Ltd, and equipped with a 0.9 x 1.0 m ball mill, was erected at Frank concentrator (Merensky Pt ore). The primary ball mills at Frank concentrator were surveyed in order to set the conditions for the base case. This data was then replicated in the pilot mill under the same configuration. Thereafter, a series of different parameters were varied in order to attempt to optimize the milling system.Some of the grinding parameters that have been studied are:•,Gate versus overflow discharge•,Open versus closed circuit•,Different filling degrees•,Different shell liner profilesOnly grate versus overflow discharge and open versus closed circuit will be discussed in this paper.It should be noted that this paper does not attempt to give a universal solution as to what milling configuration is optimum in all cases. The conclusions apply for this particular case and probably most others, but it would be advisable to consider each case on its own."

Jan 1, 2003

By M. J. Hadianfard

The effect of holding at temperature on fatigue life of a 10 vol% particulate SiC reinforced Titanium alloy has been investigated. The influence of holding time at 600°C on fatigue of this material has been studied by using tension-compression tests, scanning electron microscope and image analysis. The specimens were heated to 600°C by using a controlled atmosphere furnace; hold at this temperature for time ranging from 0 to 100 hours, and then fatigue tested at room temperature under controlled constant plastic strain. The number of cycle to failure found to decrease with increasing of the holding time. In addition the fracture mechanism and number of debonded particles has been significantly influenced by holding time at 600°C.

Jan 1, 2004

By Zhiqing Zhang, Changyun Chen, Qing Liu, Lin Lin, Zhihong Jia, Guangjie Huang, Lipeng Ding

The effect of interrupted quenching (IQ) treatments on natural aging and bake hardening response of Al-Mg-Si alloy was investigated by hardness measurements, tensile test, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that interrupted quenching at 100oC could effectively suppress natural aging and improve bake hardening response. The optimized interrupted quenching treatment is 100oC for 45min, which gives the alloy a relatively low T4 temper strength and higher bake hardening response. The formation of highly dense cluster(2) during the interrupted quenching could be the reason for suppressing the natural aging and accelerating the precipitation of ß? phase during the paint bake treatment. In addition, interrupted quenching at higher temperature (170oC) results in unfavorable properties in both T4 temper and paint bake treatment. The formation of large precipitates is responsible for these undesired effects.

Jan 1, 2015

By M. J. Reasor, J. M. Antonini, L. Wu, K. Van Dyke, Z. Ye

The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and· laboratory animals. Currently, no effective treatment exists for workers who may have been exposed to the inhalation of silica. The objective of this study was to develop an animal model in which we could evaluate the effect that anti-inflammatory steroids have on the acute silica-induced pulmonary inflammatory response. Male Fischer 344 rats were pretreated with either dexamethasone (2 mg/kg) or saline vehicle (i.p.) on days 1, 3, and 5. On day 6, the animals from the two groups were then intratracheally instilled with either silica (20 mg/0.5 ml saline vehicle) or saline vehicle (0.5 ml). Twenty-four hours after the instillations in the non-steroid group, significant increases occurred in total protein, total number of cells, neutrophils, and lymphocytes recovered from the lungs of animals treated with silica compared to saline controls. Silica also caused dramatic increases in the luminol-dependent chemiluminescence (LDCL) of lung tissue and bronchoalveolar lavage (BAL) cells. The LDCL reaction was markedly decreased by either superoxide dismutase (SOD) or N-nitro-L-arginine methyl ester hydrochloride (L-NAME). SOD is involved in the enzymatic breakdown of superoxide anion, while L-NAME, a nitric oxide (NO) synthase inhibitor, prevents the formation of NO. When the superoxide anion and NO react, they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent which may be involved in the silica-induced oxidant lung injury. When the animals were pretreated with the steroid dexamethasone, there was a complete protection against the biochemical, cellular, and chemiluminescent indices of damage caused by silica. The mechanism in which the steroid protects the lung from damage may be due to the ability of dexamethasone to block the induction of NO synthase. With further study in animals, the anti-inflammatory steroids may be useful in the treatment of silicainduced lung injury.

Dec 1, 1995

By Mark Tsirlin

Kinetics of the initial oxidation stages of diffusive silicide coatings on 8 molybdenum and niobium at 1100 - 1700 and under the pressure of 400 and 1330 Pa has been studied using methods of gravimetry and gas phase analysis of oxygen, as well as by SEK, XRD and EDMA methods. The first oxidation stage described by asymptotic equation in case of NbSi coating changed over to the stage described by parabolic equation. The asymptotic law was shown to depend on non - stationary conditions on the oxide layer boundaries. Interconnection between silicides and quartz structures, on the one hand, and peculiarities of oxidation kinetics, on the other, is [discussed. The possibility of estimation oxygen atom jump frequency in quartz and fractions of oxygen reacting with metal and with silicon proceeding from the analysis of the kinetic data was ascertained. Conditions of oxidation kine- tics transfer from asymptotic (or parabolic) stage to a non - protective "linear" stage, associated with volatile ~roduct formation, are also discussed.

Jan 1, 1995

By G. V. R. Landman

In order to obtain a better understanding of the explosion risk at the coal face, anomalies in the ignition sensitivity for different modes of ignition of hybrid mixtures of dust, methane and air were studied. Results indicated that the explosible behaviour of the working environment is highly dependent upon the ignition source and the fuel composition. For example, depending on the ignition source, the same hybrid mixture can be inert or extremely explosible. In conclusion, it is stressed how the explosion risk can be expressed in terms of a safety factor which takes into account the influence of both the fuel and the ignition source.

Jan 1, 1994

By Nick Katsikaros, A H. Gray

Gold concentrates are produced at many mines by a variety of centrifugal and gravity machines, such as Knelson and Falcon concentrators, however the subsequent recovery of gold is relatively inefficient and subject to security problems. The InLine Leach Reactor (ILR) offers a new method to recover over 95% of gold in concentrates using a simple, secure leaching process. The InLine Leach Reactor is of particular benefit in treating slow or difficult leaching sulphide concentrates and its performance can be reliably predicted from simple laboratory tests. The InLine Leach Reactor is now successfully operating in two gold mines providing benefits of high gold recovery, low operating costs, high security and ease of operation.

Jan 1, 1999

By C. Tompouloglou

The innovation in a technological field is reflected by the Research and Development (R & D) activity in it. It is explained why patent literature is a more reliable indicator than non-patent literature for the assessment of the R & D activity in the technological fields considered. Consequently the R & D activity is measured in this article through the patent applications filed in the fields considered. The pattern of patent application filings in Drilling, Mining, Tunneling and accessory technologies is analyzed at an international scale over the period 1990-2000. A statistical analysis of the fluctuation of the number of patent applications per year, per country and per technological field is performed. The technological fields are defined on the basis of the internal patent classification used in the European Patent Office. The article attempts to detect the high activity and ?cutting edge? technologies over said period, to relate them to political or financial events and possibly to foresee the ?cutting edge? technologies of the future in which potential investors could be successful. Strong patents are revealed on the basis of the frequency of their citations by the applicants in patent applications or by the patent examiners in the search report. International as well as specific national trends in the innovation are spotted and analyzed.

Jan 1, 2003

By Erwin Stötzer, Renato Fiorotto, Wolfgang G. Brunner, Manfred Schöpf

"Deep mixing methods can be used economically for the construction of cut-off or excavation support walls where other systems such as traditional soldier beams and lagging walls would yie ld unsatisfactory performance, where the installation of vibrated or driven sheet piles could cause vibration induced settlements and where concrete diaphragm walls would be time consuming and expensive. The new CSM method can largely replace the more conventional single or multiple auger methods of soil mixing or jet grouting. The cutter tool is similar to a cutter used in diaphragm walls or cut-off walls and is operated with a Kelly mounted on a drill rig. With this system much deeper walls can be installed and even hard soil layers can be penetrated. CONVENTIONAL SOIL MIXINGIn 1962 Norman Liver patented an auger-based soil mixing technique that has become the basis for the world's current technology.The deep mixing method (DMM), as it is known today, is an in situ soil treatment and improvement technology where the soil is blended with binders and/or other materials that are introduced in a slurry or dry form.Typically one or more hollow, rotating mixing shafts tipped with some type of cutting tool are mounted vertically to the mast of a base carrier and are driven into the ground by hydraulic or electrically powered rotary heads. The shafts above the cutting tool may be further equipped with discontinuous auger flights and/or mixing paddles. The binder is injected through the hollow shafts to nozzles located near the cutting tool where it is mixed with the ground to form columns of treated soil.Individual column diameters range from 0,6m to 1,5m and may extend to 40 m in depth. They can be arranged individually or in contiguous or secant patterns to produce a wide range of treated soil structures on both land and marine projects. Typical configurations are: Single elements, rows of overlapping (secant) elements, grids, lattices and blocks (Fig. 1 )."

Jan 1, 2005

By Cheng Xiangzhou

The China Ocean Mineral Resources Research and Development Association (COMRA) conducted a topographic survey in its deep seabed claim area with the SeaBeam system in 19475. After analyzing the data, it was determined that there is a group of living things several hundreds of meters in depth that significantly affect the sound waves in the frequency range of interest. We will attempt to investigate more about such influences. Physical model testing is an important means for studying the theory, and for development of the technology for geophysical prospecting. Because the manganese nodules are distributed over the sea floor in irregular patterns, it is hoped that study of the acoustic properties of manganese nodules by means of physical model testing can improve interpretation of the data of the multi-beam system and the SeaBeam system. This will provide a more reliable basis for delimiting the mineral site and evaluating the reserves in the Pioneer area of China.

Jan 1, 1996

By Robert A. Westman

The INRED process has been developed step by step by Boliden since 1972 at MEFOS, the Foundation for Metallurgical Research, at Lulea in Sweden. The demonstration - plant is number five in this series. The purpose of this plant, which has a nominal capacity of 60,000 tonnes per year of hot metal is to: 1) prove the process on a sufficiently large scale to provide the basis for construction of production plants, 2) test various kinds of raw materials on behalf of licensees, 3) train operators of the first production plant, 4) develop the process further for special applications.

Jan 1, 1983

By Francis M. Walters, Irvin R. Kramer

THE substitution of cobalt for part of the nickel in Invar was found by P. H. Brace1 to lower the coefficient of expansion. Scott1 extended the use of cobalt to alloys of higher inflection temperatures. Such alloys have a larger temperature range of low expansion than those without cobalt, and [ ] their use up to 400° or 500°C. offers decided advantages in certain applications. However, it has been found that the iron-nickel-cobalt alloys are not stable in this temperature range. EXPERIMENTAL METHODS Two methods were used in studying the stability of the low-expansion iron-nickel-cobalt alloys. Dilatometer specimens were held at 480°C, for 9 months and the change in expansion characteristics was determined. Filings were held for about 2 months at various temperatures and the change in structure was determined by X-ray diffraction. As shown by Table I, the alloys studied covered a wide range in nickel plus cobalt content (which determines the inflection [ ] temperature) as well as some variation in the ratio of nickel to iron (which controls the temperature of the gamma to alpha transformation). Included also are alloys containing carbon and vanadium, carbon and titanium and three with various amounts of copper. The alloys were melted in a high-frequency induction furnace with a magnesia crucible, using ingot iron, electrolytic nickel and commercial cobalt. Fifteen-pound heats were cast into iron molds after deoxidizing with silicon, or

Jan 1, 1941

By G. M. Behrend

"AbstractMeasurement and control systems in minerals processing plants are usually well thought out and designed. The criteria and design parameters have been interpreted correctly.However, these systems often fail to perform satisfactorily or break down altogether as a result of in-plant conditions which are unpredictable and over which the instrument systems designer has no direct control. The foresight necessary to anticipate the problems and allow for them in the systems design can only be generated by experience.This paper lists the most common of these problems and offers practical methods for their solution. It then follows with an analysis of instrument installation practices and comments on special points that need watching.Finally, instrument maintenance is discussed with a view to achieving good maintenance at the best possible economy.Good MeasurementGeneralTHE MINES and mineral processing plants of the nineteen seventies, after decades of sensible caution, have now committed themselves to extensive automatic control. X-ray analyzers are freely specified. Sample acquisition systems are efficient and automated, computers are reliable and relatively cheap, and computer control systems in conjunction with the new analyzers are operating in a good many plants and are proving to be profitable.The sight of shift foremen and floor operators assembled in front of a TV-tube and taking a computer data display as gospel truth is quite common now, and yet was quite unthinkable only ten years ago."

Jan 1, 1977

While this paper is directed towards the ?Bellambie? type of rope attachment, the principles can be applied to any brand of rope fitting however, it is a only a broad outline and the specific installation and maintenance procedures can be obtained from the attachment supplier. The types of attachment to be discussed are:- ?Thimble Type rope cappel ?Wedge Type cappel ?WRC Rope Clamp ? (Rope Glands) ??Hoist and Balance Rope Sockets In each case, the assembly and stripping (disassembly) plus the basic maintenance procedures is briefly described. A guide for Risk Assessment is also included but because of his familiarity with the installation, the end-user is in the best position to draft the final version.

May 1, 2003

By Fred V. Seibert

The Functions and the Responsibilities of the Institute The Canadian Institute of Mining and Metallurgy is unique. ln addition to the welfare of its members, it has a real interest in the welfare and promotion of one of Canada's largest and most important basic industries. It is because of this that the membership is composed of both individual and corporate members. The individual members are both technical and non-technical (Members and Associates). Both Members and Associates have the same status in the Institute and all are interested in the welfare of the mineral industry. The aims and objects of the Institute 11re twofold. The education and welfare of its individual members and the sound promotion and welfare of the mineral industry. Perhaps it might be well if we reviewed these aims and objects as stated in our Constitution: "First - To promote the arts and sciences connected with the economical production of valuable minerals and metals, by means of meetings for the reading and discu11ion of technical papers, and the subsequent distribution of such information as may be gained throo.gh the medium of publications". It cannot be denied that we have do ne a good job in this particular phase of our work. Nevertheless, there is still room for improvement. It has been suggested that we might have more discussion and, on occasions, more criticism of our papers and programmes. This can best be done if the authors will have their papers prepared in sufficient time to permit of preprints being made availa1ble before the meeting at which they are to be presented.

Jan 1, 1950

By AIME AIME

THE official opening at the 134th general meeting of the Institute was held on Oct. 6, but it was prefaced by two round table conferences on Oct. 5. The open-hearth group held the fourth of their semi-annual conferences at the William Penn Hotel, devoting the morning session to discussing a paper by R. L. Cain on the "Manufacture of Forging Steel by the Open-hearth Process," and the afternoon to discussing P. H. Shaeffer's paper on the open-hearth charge. At the Bureau of Mines, a round table conference on the combustibility of coke was held on Tuesday morning, and the afternoon was devoted to a similar conference on the testing of coke. The formal opening session of the meeting assembled in the Music Hall of Carnegie Institute at 10.30 a. m. Graham Bright, chairman of the Pittsburgh Section; called the meeting to order and presided. President Taylor welcomed the visiting members and guests to his home city and reviewed briefly the advancement of mining in the past half century during which, for ex- ample, the coal output had increased from 53,280,000 tons to 523,357,000 tons per year. He emphasized the important part Pennsylvania played in mining and brought out the principal changes that had taken place in methods. In part, his remarks were as follows: The centennial year, 1876, found the coal business of. this country, as a whole, producing 53,280,000 tons, of which amount the bituminous mines of this State yielded 24 per cent. In 1925, this country produced 523,357,000 tons of coal, of which Pennsylvania produced 24 per cent.

Jan 1, 1926

By Thomas T. Read

ONE of the major purposes of the Institute is to "maintain ... a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy." In conformance with this purpose the Institute maintained its own library for a number of years until 1912 when it was merged with the libraries of the other Founder Societies. At that time the A.I.M.E.'s share of operating expenses was wholly covered by the income from a $100,000 gift from James Douglas. But interest on the Douglas Library Fund has declined from 51/2 per cent to 31/4 per cent; the library has grown from some 50,000 volumes in 1913 to more than 170,000 in 1945, with consequently increased costs; and its costs nave otherwise risen. The Institute today contributes to the library annually about 65c per member, of which about 25c is income from the Douglas Fund, or a net charge, from regular income, of 40c per member. The annual library budget runs about

Jan 1, 1946

By AIME AIME

IN ORDER to carry on its work most effectively, the Committee on Industrial Organization (now known as the Committee on Industrial Relations) consists, of .a number of sub-committees, each composed of a chairman and members who are especially fitted to carry out the work designated by its title. With only one or two exceptions, all of these committees made reports at the New York meeting of the Institute, in February of this year, abstracts of which follow.

Jan 1, 1920

By Garforth W.

The chairman announced the new government duties of the out-going President, Sir Thomas Holland, and the formation of a new standing committee on mining to advise the Advisory Council for Scientific and Industrial Research on suitable projects for grants. Some of the potential lines for investigation into the best methods of winning and presenting coal in the best commercial condition include wasteful practices in operating steam boilers, national loss due to neglecting recovery of coal by-products, and the leaving of large areas of coal for fear of spontaneous combustion or as boundary pillars and support

Dec 1, 1916

By N J. Welham

The Intec Copper Process is an environmentally advantageous hydrometallurgical process for the production of high purity copper and associated precious metals from copper sulphide concentrates. The process uses a mixed chloride-bromide lixiviant in an elegant cyclic circuit to leach the copper into solution, rejecting the iron as stable hematite rather than as unstable jarosite. After purification of the pregnant liquor, copper is electrowon at London Metal Exchange Grade A purity, while the anodic energy of the cell is stored as the soluble species, HalexTM, for recycle as the regenerated lixiviant to the leach circuit. Both gold and silver are leached and recovered directly from this cyclic process without resorting to cyanide leaching of the residue. No liquid emissions result from the Intec Copper Process, whilst spent air and water vapour from the leach are released to the atmosphere. The sulphur in the minerals reports to the solids residue in elemental form, without the need for expensive handling of voluminous gaseous sulphur dioxide streams found in smelters. A significant difference to competing smelting and hydrometallurgical processes is that any mercury entering the process from the sulphide concentrate feed is recovered rather than reporting directly to waste or polluting the environment. Outside the process circuit itself, the Intec Copper Process has several notable environmental advantages over competing technologies: Flexibility of scale with low capital and operating costs allow operation directly at the mill head at production rates as low as 15 000 tpa, significantly reducing environmental impacts from concentrates transport. The ability to handle low-grade and dirty concentrates often allows greater recoveries in the mill, improving both the economics and environmental acceptability of a mine by reducing metal losses to tailings. A comparison of the total energy requirements of the Intec Copper Process with those of competing technologies shows that the Intec Copper Process has the lowest energy consumption of any of the known hydrometallurgical processes, as well as improving upon pyrometallurgy under appropriate conditions.

Jan 1, 2002