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By William P. Blake

The attention of travellers, upon the desert bordering the Great Colorado of the West, is often arrested by broad stretches of pebble-covered plains, or mesas, glittering in the sunlight from the myriads of polished surfaces, giving, at a distance, the appearance of a sheet of water. It is not alone the well-rounded, polished surface of these pebbles which commands attention, but, in addition, their nearly black or darkbrown color; and, above all, their uniform distribution in a level sheet, covering the plain in a continuous layer or pavement like a vast mosaic without sand or soil. Hundreds of square miles along the lower Colorado, especially in Yuma county, Arizona, and on the borders of the Colorado Desert in California, are thus covered. It is evident that the former cxtent of such pebbly plains was much greater than now, for the continuity of the mesa is broken into by the numerous dry arroyos or " washes " formed during exceptional showers or deluging rains. In some places there is an underlying bed of pebbly conglomerate, a mixture of pebbles and sand; in others the pebbles rest on a sandy, earthy foundation. The rounded pebbles are distinctly alluvial in origin, and pertain to the ancient Colorado drainage system; but it is not comprehensible that such regular layers of polished pebbles could have been left by subsiding floods or river action. Attention was early directed by me to these remarkable plains, first examined in 1853, when exploring for the United States and seeking a practicable route for a railway to the Pacific coast.* The cut and polished surface of the pebbles

Jan 1, 1904

By J. R. CAIN

SAMUEL L. HOYT, ? Nela Park, Cleveland, Ohio (written discussion?). The work that Dr. Cain is doing on gases in steel should have a highly important bearing on investigational work in connection with steel-making practice. We found, for example, in our work in connection with the use of manganese in open-hearth practice that we needed expressions for the manganese efficiency and the "condition" of the steel. To get these figures we assumed that we would need to know the amount of FeO at different stages of the heat and the amounts of the gases present. This required simultaneous analyses of our samples for FeO and the gases and Dr. Cain seems to be the only investigator who has considered the analytical work from this point of view. That he has done so is very encouraging and it is to be hoped that his work will solve the mys-teries now surrounding this neglected phase of steel metallurgy. Those interested in the Ledebur method for use in connection with the efficiency of manganese as a "deoxidizing " agent will he disappointed to learn that more recent work at the Bureau indicates that Ledebur determinations are not reliable. The principal source of error seems to be due to the partial reduction of the ferrous oxide by the carbon present in the steel. However, it seems like an unnecessary criticism of the Ledebur method to state (p. 1319) that it proved of little value because it showed little differences in oxygen for a series of steels treated with ,various reagents and showing variations in physical properties and free-

Jan 12, 1919

By W. D. Judge, Z. W. Xiao, G. J. Kipouros

Rare earths have taken a prominent position in the Hi-Tech field after the discovery of the NdFeB permanent magnets. Their use in the magnets sparked miniaturization of the communication devices such as computers and mobile phones and are being considered in many more applications. Potential applications of rare earth elements in energy conversion technologies including wind turbines, photovoltaics, and other renewable energy systems are reviewed, along with sustainability considerations and production processes.

Mar 1, 2017

By M. E. de Morton

Low frequency-internal friction measurements on annealed chromium have shown a marked increase in damping below - 40°C which is strongly strain amplitude dependent. An interpretation of these results is given in terms of the motion of antiferromagnetic domains assumed to exist below - 40°C. A time effect on internal friction was measured after slight overstraining. After heavy deformation a pemzanent, five-fold increase in internal friction was observed at -45°C and the character of the internal friction us temperature curve markedly changed. Full recovery of damping was not attained until after heating to 800°C. A qualitative interpretation of some of these effects is given. THE aim of this preliminary investigation was to study the internal-friction characteristics of chromium containing comparatively small quantities of interstitial solutes in the fully annealed and heavily worked condition. Marked anomalies in a number of physical properties of chromium at temperatures near 40°C have been observed1 and an investigation by neutron diffraction' has shown that chromium at room teyperature is weakly antiferromagnetic with a Nee1 temperature at approximately 200oC. No irregularities in the degree of antiferromagnetic ordering have been observed at -40°C, the transition temperature, and a complete explanation of this transition in chromium is still awaited. Recently weiss3 has suggested that an ordering effect of nitrogen in the face-centered interstices of the bcc lattice of chromium could be responsible for the superlattice detected below 200 °C in the neutron diffraction experiments. EXPERIMENTAL MATERIAL AND METHOD Specimens 10 by 0.030 in. diam were prepared from ingots of arc-melted electro-deposited chro-

Jan 1, 1961

By C. H. Mathewson

ABOUT fifty pages of Henry M. Howe's profound treatise, "The Metallography of Steel and Cast Iron," are devoted to twinning with special reference to the origin, nature and general significance of the Neumann bands in ferrite. Howe believed with Osmond and Cartaud1 that the Neumanns are mechanical twins and his careful observations leave no doubt that these straight-sided narrow bands habitually occur parallel to trapezohedral planes of form {211}. Attempt's to develop the structure of the bands by various methods so that their identity could be established beyond question have not been conspicuously successful. Howe thought that they deflected slip bands. Some of the etching figures which have been developed within and adjacent to Neumann bands support the contention that they are twins. A good example of this effect in ferrite containing 0.6 per cent. of nickel and 1.3 per cent. of phosphorus, originally due to Harnecker and Rassow,2 was reproduced in. the 1928 lecture before the Institute of Metals Division on twinning in metals.3 In this case, the sides of the figures might represent the traces of cubic planes laid bare by etching a properly oriented grain of ferrite, twinned along a plane of form {211}. Our own observations in this direction may be represented by Fig. 1 which shows in a deeply etched cavity in the boundary region between a Neumann band and the original crystal two small crystal surfaces which resemble the faces meeting at a reentrant angle in the simple cube twinned along a bisecting plane of form {211} as sketched in Fig. 2.

Jan 1, 1928

By Peter Swanson, John Rettkowski

As part of a research program to reduce injuries and fatalities in the U.S. mining workforce, NIOSH is investigating the potential use of noncontact vibration measurements to identify hazardous ground fall conditions. In the present study, the effectiveness of remote vibration sources in exciting resonant responses in damaged structures is examined. Initial experiments were performed on a damaged concrete slab in a controlled environment. Vibration response was measured with a laser Doppler vibrometer using both single-point and two-dimensional array recordings. Excitation sources included direct mechanical impacts to remote portions of the slab and a remotely located industrial demolition hammer. Surficial damage was effectively delineated with both sources through visualization of vibration response in spectral bands selected to discriminate wave propagation from large-scale slab resonance effects.

By H. B. Fuqua, B. E. Thompson

The area discussed in this paper, commonly known as the West Texas district, is easily divisible into three geologic provinces, the Midland Basin to the east, the Delaware Basin to the west and the West Texas structural platform separating these two. Production in Garza, Scurry, Mitchell, Howard, Glasscock, Irion, Reagan and central Crockett counties is associated with the east flank of the Midland Basin. That in Loving and Reeves counties is associated with the Delaware Basin. All other production and developments discussed in this paper belong to the province of the West Texas structural platform. Because of certain developments that have occurred during the past year, it has been found necessary to slightly revise one of the fields as grouped by Mr. Reith in last year's paper1. The Scarborough-Leck field has been broken down as follows (Table 1): The Leck field is shown separately because it is producing from dolomite; while the Scarborough area, producing from sand, is regrouped and designated as " Scarborough-Kermit-Halley," which includes the producing sand belt across Winkler County from Ward County to New Mexico. It is believed that this is a more logical division of Winkler County and that considerable future work will be avoided by making this change before further production figures have accumulated under the present set-up. A number of new fields are listed in Table 1, some of which may represent extensions of other produeing arras. The authors, however, are inclined to believe that they represent new fields. In either event, less work is involved ill adding two areas together, if they later prove to be one, than in attempting to separate a maze of production data into two fields after they have been erroneously carried as one for a number of years. The Howard-Glasscock field is designated in this review as the Chalk-Roberts field and the Denman production on the Howard-Mitchell County line is included in the Iatan field. Development during 1934 Development in West Texas during the year 1934 showed a marked increase over the previous year both in exploration and ill exploitation

Jan 1, 1935

By Daniel Johansson, Markus Danielsson, Håkan Schunnesson

In sublevel caving, blasted material flows gravitationally into the drawpoint from above in a periodical manner. This type of flow behavior entails muck pile conditions that are variable along the course of extraction. The effect of this variability on the LHD (Load-Haul-Dump) operation in terms of loading efficiency and ability to undermine the blasted ring is not fully understood as of today. This paper presents results from a field test in LKABs Malmberget mine in Sweden, where the influence of fragmentation on the loading operation has been studied in detail. Drawpoint filming was conducted for extraction of two rings equivalent of roughly 10000 metric tons (~9842 long tons) of material each. The analysis includes fragmentation measurements, muck pile classification, and general estimations in terms of loadability. Further, an evaluation of LHD machines from two different manufacturers was conducted to identify and highlight differences. The results show that fragmentation, muck pile compactness, and flow characteristics are all interdependent. Flow disturbances and the subsequent loading of compacted fine material in the back of the ring have been identified as the main reason for occurring problems and prolonged digging times. However, the ability to sufficiently undermine the blasted ring has been identified to primarily depend on digging depth which is only observed to be high during flow disturbances. An absence of flow disturbances seem to promote high loading efficiency but simultaneously limit the maximum digging depth. A mid-range particle size distribution with a low amount of fines has proven beneficial for overall loading efficiency. The various LHDs employed showed significant variations in terms of ability to handle difficult loading situations (e.g. compactness, boulders, etc.).

Jan 1, 2018

By R. N. Chakravorty, R. J. Kolada

Explosions of methane in coal silos and coal ships is an ever present hazard. Recent investigations have shown beyond question that considerable accumulations of methane do occur in coal storage silos and numerous recent explosions in coal transport shipping strongly indicates that the same conditions also exist in ship storage holds. Investigations have shown that the main concentrations of methane occur within the actual coal pile. Within this region normal silo and ship ventilation systems are ineffective. The main 1ine of defence is therefore to exclude potential sources of ignition or to place the coal in an inert atmosphere, or both. This paper presents the results of a methane survey of all operating silos in Western Canada. These results demonstrate that a serious and widespread hazard of explosion exists. This paper also discusses various methods by which this hazard may be reduced including methods of venti1ation, inertization, microbiological control and early warning systems.

Jan 1, 1987

By J. A. Herbst, A. E. Oblad, Y. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50% of the operating cost. Improvements in plant operations have resulted in up to a 15% reduction in energy usage (kw-hr/t). These improvements have been made through the optimization of grinding efficiency and the use of expert model-based control systems. Optimization involves the determination of the levels of the critical-operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory test work and through computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding-circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1997

By W. K. Utt, C. C. Woodward, W. L. Howie, G. G. Miller

The process of roof drilling and bolting is one of the most dangerous jobs in underground mining. In the United States, roof drilling and bolting results in about 1,000 accidents with injuries each year. Researchers, from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health are studying the feasibility of using a drill-monitoring system to estimate the strength of successive layers of rock and assess the integrity of a mine roof. Such a system would allow roof drill operators to be warned when a weak layer is being drilled. Using measurements taken during drilling, a neural network can classify mine roof strata in terms of relative strength. The concept has been proven in principle. This research project was undertaken to increase the safety of underground miners, especially those involved in roof bolting. The system should be applicable to the mobile drills now used in underground mines, and the system would likely find wider application as well.

Jan 1, 2003

By B. R. T. Simoneit

The conversion of organic matter to petroleum by hydrothermal activity is an easy process, occurring in nature in many types of environments. Geologically immature organic matter of marine sediments is being altered by this process in Guaymas Basin (Gulf of California), Escanaba Trough and Middle Valley (northeast Pacific), Bransfield Strait (Antarctica), and Atlantis 11 and Kebrit Deeps (Red Sea). Contemporary organic detritus and viable microorganisms are also converted in part to petroleum-like products by the same process when present to become entrained, as for example on the East Pacific Rise at 13o N and 21o N and on the mid-Atlantic Ridge at 26oN. The hydrocarbon products (methane to asphalt) generated in all these areas have been elucidated in terms of composition, organic matter sources, and analogy to reservoir petroleum. This petroleum represents a major input of carbon to the primary chemosynthetic productivity of hydrothermal vent systems and may be important to interactions with metals in hydrothermal ore formation.

Jan 1, 1991

By Lynn B. Hales, Randy A. Ynchausti

Because of the high economic value associated with small improvements in the operating performance of mineral processing plants, innovations in instrumentation, stabilization and expert control systems have been an ever-present part of the landscape in plants throughout the world since the I 960s. Expert control systems are computer programs that continuously monitor plant conditions; contain "expert knowledge" concerning the process, equipment and operational knowledge; and make timely recommendations for new process set points or even directly change the process set points to achieve desired management goals. Early rudimentary expert control systems first appeared in the early 1970s. They have grown from small, experimental but ambitious projects in which single unit operations were controlled to plant-wide systems that include technologies used in the U.S. space shuttle program. Experiences and results of applying these systems throughout the world will be explained discussed and analyzed. Typical results will be outlined and the use of expert control in the future will be projected.

Jan 1, 2000

By A. Alvarez

In this work, mesophilic and thermophilic cultures have been used in the presence of silver as a catalyst. Chalcopyrite and byproducts of bioleaching were characterized in order to: a) obtain information about the kinetics control of the process, and b) explain the different behaviour observed during the mineral attack. With thermophilic microorganisms (68°C and Norris medium as nutrient) the reaction stopped at approximately 65% copper extraction, with and without Ag ion addition as a catalyst. The remaining chalcopyrite appears surrounded by hydronium jarosite (with ammonium ion in substitution in the "alkaline site"), goethite and elemental sulphur. With mesophilic cultures (35°C and 9K medium as nutrient) the reaction stopped at approximately 25% copper extraction (without Ag) and approximately. 85% extraction (with Ag). In both cases, the remaining chalcopyrite was surrounded by agglomerates of ammonium jarosite (with hydronium ion substitution in the "alkaline site") and some iron oxides and/or hydroxides.

Jan 1, 1999

The nickel suppliers are hard at work across the entire spectrum of the industry-from exploration and mining on the one hand to the development of new applications of this unique metal on the other. The reason-a surging demand for nickel by the free world. Evidence of interest and activity in nickel abounds. Companies such as Anaconda, American Metal Climax, Kaiser Aluminum & Chemical, Patino, Newmont-firms that have not been in the nickel industry before-are now involved in various exploration and development ventures around the world. International Nickel, Falconbridge, Le Nickel and Sherritt Gordon-the big names in the industry -have committed vast sums of money and talent in a variety of new developments designed to ensure their status as leading producers of this commodity. As a result, the world is now seeing a rapid build- up in nickel capacity, and in this issue of [ ], the editors have prepared a summary of these fast- moving major developments.

Jan 10, 1968

By A Hewitt

Portland cement is the chief binding ingredient in mine backfill. In the presence of water, the chemical compounds within portland cement hydrate causing hardening and strength gain. During hydration, heat is generated. In certain cases, hydration heat may be produced significantly faster than it can be dissipated, which can create high temperatures in the underground environment. This paper presents the results of a series of investigations aimed at quantifying the heat generated by cemented backfill during hydration. Scaled stope models, instrumented with thermistors, were used in the investigation. Heat transfer to the hanging wall, orebody, footwall and cross-cut and production drifts was assessed during the backfill curing process and relationships between cement content, cure time, and heat generation were developed. The results of this work will assist mine operators in predicting the heat generated by cemented backfill and provide the necessary information to implement effective engineering control of heat in the underground environment.

Jan 1, 2005

By Kurt F. Weitz

"The number of materials that can be classified as fillers covers an extremely wide range: this paper outlines those fillers of the industrial mineral type that find extensive application in the paint and plastics industriesIn the paint industry, mineral fillers are known as extender pigments. Extenders are added to paint and plastic compositions to (1) lower the cost and (2) rein-force or modify the physical properties of a composition.Commonly used extenders are classified according to chemical type and discussed in terms of the change in physical properties that they impart to a paint or plastic film. Available cost reductions and data on the consumption of extenders in the Canadian paint industry are also included."

Jan 1, 1970

By P Mikula, B Darlington, J Graham, P Young

In underground mines experiencing dynamic events, there is an ever-present challenge to design and maintain a capable ground support system. One key component of ground support systems is surface support, which serves the essential roles of retaining failed rock and transferring forces generated by surface displacement to rock bolts or other support elements. Observations underground show that in many instances, standard mesh panels alone do not provide sufficient dynamic support to retain substantial bulking failures imposing displacement onto mesh, and in such cases Mesh straps and W-straps may be employed. Determining the performance of surface support elements proves to be difficult, with a multitude of variables at play in the underground environment. Quite comprehensive work has been completed on laboratory testing of surface support systems; however, very little work has been conducted on in situ dynamic testing of Mesh straps and W-straps. In 2019 in Western Area’s Flying Fox Mine, in situ dynamic testing was conducted on a series of Mesh straps and W-straps using Sandvik’s in situ Dynamic Test Rig (DTR). The testing regime applied impact energies from 5.1 to 15.3 kJ to Mesh straps and W-straps. The performance of the straps that did not fail was a maximum absorbed energy of 9.3 kJ and 14.2 kJ for the Mesh straps and W-straps respectively. The testing successfully demonstrated the ability of Sandvik’s DTR to test not only rock bolts, but also surface support elements, creating new testing and research possibilities. The testing also provided important design guidance data that is not practicable to obtain using laboratory dynamic testing facilities.

Nov 29, 2022

By C. Nesbit, N. Duru

During the cyanide leaching process of gold and silver, ores that come from the transition zones which typically con-tains low levels of sulfide may produce one or more of the following reduced sulfur species: sulfide (HS ), polysulfides (Sn ), thiocyanate (SCN ), thiosulfate (S2O3 ), trithionate (S3O6 ), tetrathionate (S4O6 ), pentathionate (S5O6 ) and hexathionate (S6O6 ). The actual speciation of the reduced sulfur species in the circuits will primarily depend on the re-dox potential, pH, cyanide levels and existing sulfur species in recycled process water, as well as the presence of other reac-tive metal species. Development of an accurate analytical method for sul-fur species in cyanide leaching units of gold ores where sul-fur speciation occurs has an important role in explaining the metal recovery deviations. This study presents the speciation of sulfur species and development of an ion chromatography method to analyze the reduced sulfur species thiocyanate, thio-sulfate, trithionate and tetrathionate in cyanide leaching circuits for gold ores. The method developed has resulted in the precise quantification of target sulfur species in leach solutions.

Jun 1, 2024

By V Cullinan, D Buchanan

The Brunswick plant is located in Costerfield, approximately 40km east of Bendigo in central Victoria. Crushing, grinding, gravity gold concentration and flotation methods are used to produce a saleable gold concentrate and an antimony-gold flotation concentrate. This paper discusses the improvements made within the processing plant which have resulted in a 99% increase in throughput over nameplate capacity of 6 250 average tonnes per month to 12 445 average tonnes per month and increases of 12% gold (from 2007 average of 78% to 2014 average of 90%) and 16% antimony recovery (from 2007 average of 79% to 2015 average of 95%). This combined effort has resulted in an increase of equivalent gold ounces (AuEq oz) produced from 2010-2014 of 15 872 to 82 574 – a 66 702 increase.AuEq oz= Au oz +Sb t × Sb (US$/t)Au (US$/oz)CITATION:Buchanan, D and Cullinan, V, 2015. Improvements in bi-metal production at the Brunswick Plant, Costerfield, in Proceedings MetPlant 2015, pp 267–272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015