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By C. C. Popoff

The growth of the aluminum-smelting industry in the Pacific Northwest, resulting from national defense requirements, emphasized a need for local sources of alumina to supplement the alumina production shipped from the East. Because supplies of foreign bauxite were being interrupted and our domestic bauxite reserves were inadequate, it was necessary to expedite the investigation of other possible sources of alumina during World War II. A program of investigation of high-alumina clay deposits in the Northwest was carried out jointly by the Federal Geological Survey and the Federal Bureau of Mines. As part of this program the Cowlitz clay deposits near Castle Rock, Wash., were explored by the Bureau of Mines in 1942-43. These deposits are near railroads, tide-water, and Bonneville Power Administration lines and within 22 to 100 miles of 4 aluminum-reduction plants.

Jan 1, 1955

Jan 1, 1967

By Zvonimir Ester

The course of motorway tunnel under construction was set only 2 m away from the main motorway. The thickness of the tunnel overburden rock was 9 m. During the tunnel construction the traffic on the motorway was not supposed to be interrupted. The tunneling was carried out by NATM with classical drilling of blastholes and by blasting.

Jan 1, 1998

Over 800 mines have closed in Australia in the past 25 years. This paper summarizes the data obtained from those closures and includes all Australian States and Territories and all commodities, including metalliferous, coal and industrial minerals. Twenty five percent of the mines closed due to resource exhaustion or depletion; 24% due to high costs, price drops, or declining grades; 8% due to open pit resource depletion (but with underground reserves remaining) or underground reserves depleted (but plans to open cut remainder) and 7% due to receivership or voluntary administration. The environmental, social and economic impacts of these closures are also significant and include acid mine drainage and impact on mine employees. An understanding of the causes of premature mine closure will better equip mining companies and governments to better manage future mine closures, wherever in the world the mines are operating.

Jan 1, 2007

By F. Weinberg, L. MacAulay

DAVIS,' in an investigation of solute redistribution along molten rods of dilute silver in tin, concluded that at horizontal temperature gradients below approximately 5°C per cm very little convective mixing takes place. Cole and winegard2 observed temperature oscillations in horizontal melts of tin, with temperature gradients of several deg per cm. They associated the temperature oscillations with the presence of convective flow in the melt. At temperature gradients less than 1°C per cm they did not detect convective flow. In the present work, direct measurements of con-vective flow in liquid tin have been made using a radioactive tracer technique. The results indicate that extensive convective flow occurs at temperature gradients below those previously reported. The apparatus used to determine the extent of con-vective flow is shown in Fig. 1. The graphite boat Fig. l(a), has two rectangular channels both of which contain molten tin. Radioactive Ag110 in the form of Sn-0.2 pct Ag alloy was introduced at the end of one channel, by rotating the cylinder shown. A series of fixed thermocouples were positioned along the center of the second channel to determine the temperature gradient. It was assumed that the two channels had identical temperature distributions. The graphite boat was inserted into a vycor tube which was surrounded by a multiple winding tube furnace as shown in Fig. l(b). The tin was melted in an argon atmosphere. The distribution of Ag110, as a function of position along the boat at a given time after introduction of the ~g"', was determined with the

Jan 1, 1970

By J. B. Hedrick

In 2004, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Major uses for these commodities were in automotive catalytic converters, petroleum fluid-cracking catalysts, permanent magnets, glass-polishing compounds, ceramics, metal-alloying additives, phosphors and rechargeable batteries. Consumption of refined rare-earth products decreased. The United States was a major importer and exporter of rare earths in 2004. Yttrium was not mined or refined in the United States in 2004. Imports from China, France and Japan accounted for most of the U.S. supply of yttrium compounds for refined yttrium products.

Jan 1, 2005

By William W. Adams

Accidents to men employed in the quarrying and related industries of the United States were more numerous, absolutely and relatively, in 1937 than in 1936. Fortunately, the entire increase was in the category of nonfatal injuries, as accidents causing death declined in number and in proportion to the number of man-hours worked. Employment increased. More men were employed, more man-days and man-hours were worked, and the average employee had more hours of work than in 1936. Reports covering all commercial operations showed that 84,094 men were employed an increase of 5.1 percent over 1936. The number of man-hours of work performed by the industry was, 158 millions, an increase of 7.6 percent. Seventy-seven men were killed by accidents, a, reduction of 14 from the year before, and 6,348 men were injured and disabled for more than the remainder of the day on which the accident occurred, 11 percent more than in 1936. The fatality rate of 0.49 per million man-hours of exposure in 1937 compared favorably with the rate of 0.62 for the previous year, whereas the non-fatal-injury rate of 40.10 was 3.2 percent higher than the rate of 38.87 for 1936.

Jan 1, 1940

By D. Prince, G. Nollet

"Since 1994, Aur Ressources has operated Louvicourt mine, a zinc and copper mine close to Val d’Or, at a rate of 4300 t/d. Ever since the start-up of the plant, management has encouraged innovative approaches in reliability. The first of three papers will discuss the vibration monitoring program in place. The program will be described and two examples will be given: detection of a rolling bearing defect on a pinion driving the ball mill and identification of wear on the bearings of the flotation cells. Figures on the return on investment and the costs of a monitoring program will also be given.The second article will discuss the lubrication aspect. Since the establishment of a good monitoring and oil analyses, Louvicourt mine decreased its oil consumption by more than 38 000 L/yr. In addition, the company set up an oil regeneration system that restores the original properties of oil.The third article will cover the management aspect. Work organization as well as the management philosophy enabling the employes to push predictive technology to higher levels will be examined in detail. The key elements which made it possible for Louvicourt mine to position itself among world-class companies in the organization of maintenance will be discussed."

Jan 1, 2002

By M. L. Baharani

Looking for an idyllic paradise that has investment and business potential as spectacular as the stunning views of mountains, the rich Ganesh Himal zinc-lead deposit exposed between 4,050 m and 5,000 m is the answer. Arising from the sea floor in a span of 55 million years, the enchanting Himalayas had remained one of the most potent factors influencing the Asian region. The challenges of the mighty Himalayas notwithstanding, it continues to provide opportunities for the humankind in optimum usage of the natural resources and sustainable development. Optimal management of natural resources in mountain areas through decision support tools offered by remote sensing will go a long way in realization of the Ganesh Himal Zinc-Lead Project. The authors have a real life endeavor spanning over 37 years in developing a mining industry in a mountainous region of Nepal and an attempt to integrate with the development of other natural attributes of the region. With rapid acceleration of science and technology, humankind has acquired power to transform his environment countless ways and on an unprecedented scale. While mineral resources are the pillars on which we have built industry and infrastructure, industrial countries in the North have been in the forefront of technological advancements, the developed countries of the South have been at the receiving end of exploitation of mineral resources worldwide. A relationship with natural environment, re-crafted by the civilizing impulse, to meet human demands are upcoming challenges for management of natural resource in sustainable manner for a livable world.

Jan 1, 2008

By N. A. Gokeen, M. Ohtani

EFFECT of elements on the solubility of carbon in liquid iron is useful in calculating and correlating a number of thermodynamic properties as shown elsewhere in detail.' Kitchener, Bockris, and spratt2, and later Turkdogan and Hancock3 have investigated the effect of sulfur on the solubility of carbon at various temperatures and concentrations. For any chosen sulfur concentration, the solubility of carbon reported by Kitchener et al. is considerably lower than that by Turkdogan and Hancock. It was therefore felt that a reinvestigation of this problem was necessary. EXPERIMENTAL METHOD An alloy of Fe-C-S .was prepared with electrolytic iron and ferrous sulfide melted by induction in a graphite crucible, 4 in. high 1 1/2 in. ID under a CO-atmosphere. The temperature, held at 1500" ± 5°C in all experiments, was measured with a Pt-Pt + 10 pct Rh thermocouple immersed into the melt. In order to assure saturation with carbon, the melt was stirred with a graphite rod. After approximately 1 hr at 1500 °C, a sample was obtained by sucking the melt into a silica tube, 4 mm ID. The sample was then analyzed for carbon and sulfur by usual methods. RESULTS The results are presented in Table I and plotted in Fig. 1 with the individual values of Turkdogan and Hancock.3 Scattering in the data is equivalent to 3 pct or less in carbon analysis. The broken line represents the empirical equation obtained by Kitchener et al. from their data. It is evident that the present data are in good agreement with those of the former investigators but in disagreement with the latter. The cause for this discrepancy cannot be readily offered since the experimental methods in the three investigations were nearly identical. Additional evidence corroborating the author's results may be presented in the following manner. The difference between the solubilities of carbon in the ternary Fe-C-X melt with a small concentration of any element X, and in the binary Fe-C melt is %?C = %CIII-%CII [1] where %?C is the change in solubility, and %CIII and %CII are the solubilities in the ternary and the binary systems respectively. The value of %Cii

Jan 1, 1961

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977

By J Geronimo, P Kumar, Z Yussupova, M Yahyaei, M Powell

This work goes beyond the general perception of how the well-known mine to mill process can be applied, by applying deeper knowledge along the mining chain. Grade deportment and dilution are considered at the mining stage, and modelled with the new SMI blast movement simulator, linking with the block model data. Assessing the shift to a considerably more competent section of the orebody is quantified via substantial milling trials at standard and higher-intensity blasts. These were stockpiled for batch processing through the mill to ensure feed integrity. The trial work included operating the mill at widely different fillings to develop Grindcurve milling responses. Additionally, model informed process control is initiated via a mill prediction tool.It has been found that accounting for blast movement for the higher intensity blasts could generate additional value of around $1.5M per blast. With the high-intensity blast and changing mill control, the plant was easily able to exceed projected mill throughputs with the far more competent Pipeline ore. Strategies to shift the workload and debottleneck the milling circuit were proposed and proven during the milling trials, demonstrating an increase in throughput of 7 per cent despite running at a lower SAG mill speed, and potential of 16 per cent for increasing the SAG mill to standard operating speed. A number of process improvement opportunities have been identified to enhance current productivity and ensure long term capability to process the considerably more competent future ores. All of this is being linked in with the major digitisation program at the Barrick Cortez site, with an objective of linking all the data into a mine-wide process optimisation system, that can embed the processes by providing process-wide data access and production support via the future dynamic models linking ore body knowledge to productivity along the full process chain.CITATION:Powell, M, Yahyaei, M, Geronimo, J, Yussupova, Z and Kumar, P, 2018. The designed approach to mill liner optimisation – experience at Pustynnoye mine, Kazakhstan, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 595–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By P. Amelunxen

This paper presents the authors? personal experiences in the design and operation of moly separation circuits in copper-moly concentrators. Topics discussed include column cells versus mechanical cells; use of nitrogen; use of CO2 and sulfuric acid for pH modification; and general equipment selection and sizing. A benchmarking of main operating parameters for industrial plants is presented. Upgrading curves for commercial column and mechanical cleaning circuits are also presented, showing that with average flotation kinetics and rougher concentrate grades, technical grade concentrates can be easily achieved with five column cells operating in counter-current configuration.

Jan 1, 2009

By H. M. Lewis

The current status of the international zinc market is summarized, and a supply /demand outlook is presented for the next five years. A number of technical problems facing the industry are outlined. Introduction ZINC has sometimes been called the unknown metal. Considering that on a world basis it ranks third among non-ferrous metals in production and consumption, zinc retains a certain modesty. It has no distinctive colour like copper, lacks the low density of aluminum or magnesium and is not always easy to identify as a product. The 'spangle' of galvanized steel is probably zinc's most distinguishing feature. The purpose of this article is to develop an over-all review of zinc. Starting with the current position of the metal, the major factors that will shape its future will be described so that an assessment of the outlook for zinc can be made.

Jan 1, 1978

By R. W. Smith, D. L. Taylor, K. A. Altman

Recent research has shown that traditional sensitivity, what if and best case/worst case analysis of metallurgical data has the potential to over estimate the value of mining projects. Use of simulations, which rely on the input of statistical information, may provide more realistic predictions of the value of future projects. Actual metallurgical data is used to demonstrate that analyzing the data from a statistical perspective can give insight into completing an optimum amount of metallurgical testing and a mechanism to determine that samples used for the testing are truly representative of the ore that will be processed.

Jan 1, 2000

The Bureau of Mines has reviewed those portions of the "Tariff Schedules of the United States Annotated 1963" that are of interest to the minerals industry. This study shows to what extent rates of duty were altered (increased or decreased), and provides a bridge where possible from the old Schedule A classification sys tem to the new TSUS system of statistical reporting of import data. In general the new tariff has corrected previous classification defects and inconsistencies, but the rates of duties have not been materially changed.

Jan 1, 1965

By C. H. Bucknam

Principles of Green Chemistry provide useful guidance for sustainable mineral process development. Laboratory bench scale testing was carried out using pregnant cyanide leach solutions, and a number of commercially available mercury precipitation reagents were compared using jar testing to determine the most efficient and selective reagents for mercury precipitation. The most efficient reagent identified was sodium polymeric thiocarbonate (NaPTC).Coagulation experiments with fine diatomaceous earth resulted in a stable precipitate, with good settling properties. On line monitoring of the mercury in solution is recommended for process implementation to conserve reagent removing approximately 90-95% of the mercury with minimal silver and negligible gold losses.

Jan 1, 2004

By D. Nyembe, B. Mamba, Antoine F. Mulaba-Bafubiandi

Copper and cobalt are generally electro-won from their aqueous sulphate solutions. After optimised leaching of their ores, concentrates or calcine bearing minerals, the leachate is clarified and suitably purified prior to the electrolytic extraction of the metal of pursuit (Pearcy, 2006). Solvent extraction (SX) using appropriate organic solvents and ion exchange (IX) with relevant resins are known purification processes used for copper and cobalt recovery (Stanely, 1970).As zeolites in general and natural zeolites in particular, demonstrate ion exchange properties (Korkuna et al., 2005), an attempt has been made to use Southern African natural clinoptilolite in the recovery of copper and cobalt from their aqueous sulphate solutions. Initially, synthetic Co and Cu solutions were prepared. Preceded by laboratory ore leachate, plant solutions are to be used. AAS, XRF, XRD, Mossbauer spectroscopy and BET were characterization techniques used. Natural clinoptilolite was used as-received as well as acid activated; and cobalt and copper extractions were performed at room temperature.

Jan 1, 2007

By Edward H. Robie

Jan 1, 1971