Search Documents

Almost all of the world?s zirconium is mined in the form of zircon (ZrSiO4), the majority as a coproduct of titanium mining from heavy mineral sands deposits. These are placer type deposits, in which the dominant mineral is silica but which also contain a suite of ?valuable minerals,? often consisting of a mixture of titanium minerals, various alumino-silicates and zircon plus a range of other mineral species. The composition of the valuable minerals in such deposits is known as the mineral assemblage. There is no reasonable consistent geological relationship between zircon and titanium minerals. They can derive from separate igneous rock deposits that rarely occur together. The connection emanates once these separate rocks have been eroded by weather and water, often across a very long geological period. Once this has happened, zircon and titanium minerals often find their way to the same locations because they share two major characteristics:

Jan 1, 2011

By Richard I. Barnhisel

At the Sinclair Study Site it was found that the deeper the soil the greater the yield of corn, soybeans, wheat, alfalfa, and timothy. Yields at this location were generally lower than those at the Alston Surface Mine. At Alston the non-prime land treatments generally produced greater yields for all crops than did the prime farmland treatments, however, the intermediate soil thickness, 20 cm topsoil over 40 cm of subsoil, gave the best yields, provided it's subsoil had been limed. From a chemical point of view, acidic spoils do not need to be buried by 120 cm or 4 feet of soil, provided adequate lime is applied to these spoils as a barrier prior to placement of good quality topsoil and only forage crops are to be grown. The burial depth must be increased to as much as 75 cm when grain crops such as corn or soybeans are to be grown. This response to burial depth appears to be related to water storage needed by the crop and not due to toxic effects of the spoils. A conventional farm tractor-mounted subsoiler increased yields of soybeans and corn the first one or two years, but the effect was diminished with time. Subsoiling did not produce significant increases for alfalfa or wheat. However, ripping with a bulldozer produced significant yield responses, especially for corn and soybeans, that have lasted for at least three years. The ripping effectively reduced the bulk density at least within the zones through which the ripper had passed. Liming the upper 20 cm of subsoil significantly increased yields of alfalfa, corn, and soybeans. There also appeared to be an interaction between this lime treatment and soil depth. Yields of some grain and forage crops may be high enough to meet target levels for bond release for prime farmland. Based on the present study, one should not expect corn yields to be high enough to meet bond release. This statement should not be considered final since the experiment is not complete.

Jan 1, 1983

By J. D. H. Strickland, K. J. Jackson

IN previous papers' ' details were given of the constructlon and use of an apparatus to study the rate of chlorine consumption and the rate of sul- fate and sulfur production when dilute aqueous chlorine solutions were allowed to react with pyrite and galena in acid solutions at or near room temperature. The reaction with pyrite was very rapid, and hence entirely transport-controlled in its kinetics, and produced only ferric and sulfate ions. The behavior of galena was much more complex and was studied in some detail. Sulfur monochloride could be detected as a reaction product and both

Jan 1, 1959

By Zygmunt Wegrzyk

Poland is rich in hard and brown coal reserves, which have become the most important, and steadily developing, primary source of energy. With 192.6 mill. t of hard coal production and 40 mill. t of exports in 1978, Poland is fourth and second in the world respectively. The paper discusses the various mining methods adopted in the country's history of mining. Particular emphasis is placed on longwails, their mechanization and equipment assembled in the form of fully mechanized face complexes suited for varied geological conditions. Measures to improve the recovery ratio of coal resources are dealt with. investment efforts undertaken in the coal industry are outlined. An account is given of the ever improving techno-economic results of coal mining. The country also exports a wide range of mining equipment and transfers its well-founded technical know-how to others. There are strong cooperative links with many foreign partners.

Jan 1, 1979

By G Campbell-Cowan

Much has been written about the fact that most transformation efforts disappoint. This paper addresses factors that should be taken into consideration in planning and implementing transformation programs to ensure success.In 2009, St Barbara commenced a transformation program to address issues of chronic poor quarterly operational performance; financial pressure caused by the unreliable operational performance; and an inability to develop business plans with integrity and to reliably deliver on the plans. As a result of a number of years of disappointing operational performance, St BarbaraÆs culture was not conducive to business success.This paper uses lessons learnt during St BarbaraÆs transformation program to highlight key characteristics of change programs that can generate significant sustainable benefits. While there were many benefits from the transformation program, the most significant impacts of St BarbaraÆs program have been transformation of the companyÆs culture and capability of people as business leaders; the establishment of a business systems framework to guide the design and development of systems; and developing support functions, for example centralised procurement and supply chain, business improvement and technical services.CITATION:Campbell-Cowan, G, 2012. Business transformation - Lessons learnt for successful change, in Proceedings International Mine Management 2012, pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By T. T. Chen

Copper anodes generated from copper scrap are relatively rich in Sn, Zn and Fe. Because of the presence of oxygen, only trace amounts of Sn occur in solid solution in the copper crystals. Thus, Sn occurs mainly as SnO2, Cu-Sn-Ni oxide and Sn-Ni-Zn oxide in the copper anodes, and Zn and Fe occur mainly as minor constituents in the Sn-Ni-Zn oxide and Cu-Sn-Ni oxide. During electrorefining, these oxide species are liberated from the copper anodes and report directly to the anode slimes. The trace amounts of Sn present in solid solution in the copper crystals dissolve but reprecipitate as Sn arsenate or a Sb-As-Sn-O phase. Accordingly, high Sn contents in copper anodes do not lead to elevated Sn concentrations in the electrolyte.

Jan 1, 2010

By J. J. Cai

The status of fossil fuel and secondary resource in metallurgy industry in China were reviewed, and conversion efficiency of fossil fuel, utilization technologies of secondary energy were studied. Fossil fuel, accounting for over 90% of energy structure in metallurgy industry, took in the highest flight in China, and a great deal of which was converted to secondary energy through the equipment of blast furnace and coke oven. These secondary energy which were mostly made of blast furnace gas(BFG), coke oven gas(COG) and Lindz Donawitz gas(LDG) occupied about 30% of total secondary energy. The way enhancing fossil fuel conversion efficiency, secondary resource recovery and the secondary energy such as BFG, COG, LDG utilization promoted to save fossil fuel was discussed in this paper. And efficient use of lower caloric value fuel was studied, such as preheating combustion air and fuel, generating electricity power etc. and regeneration purposes of high-caloric fuel was also researched, for producing hydrogen, methanol or direct reduction iron etc. The using model of secondary energy at iron and steel works was presented as fuel and chemical materials. The results suggest that utilization of these energy efficiently and reasonably could help to energy saving and environment protecting.

Jan 1, 2014

By I. Takahashi

Recently, electronic devices have become smaller for some kinds of electronic devices, thermal dissipation and electrical conductivity of conventional Fe based alloy becomes insufficient. We selected the Cu-Fe based alloy CDA19400 and optimized the wire manufacturing process. Precipitates during aging treatment were observed by TEM. The size and distribution of the precipitates varied according to solution treatment temperature. With solution treatment at 950°C, the precipitates of y-Fe as fine as 10 nm were distributed dense in the copper matrix with coherency. For the solution treatment at 750°C, y-Fe of approximately 200 nm was observed. Comparing heat resistance of drawn wires, the material at 950°C treatment was superior. Electrical conductivity decreased from 63% IACS upon aging to 29% IACS by drawing. It is considered as particular phenomena for wires where materials are drawn with high reduction ratio. By the optimized manufacturing process, we successfully developed a new wire that has superior in strength, thermal conductivity, electrical conductivity, heat resistance and repeated bendability.

Jan 1, 2007

By R. Mensah-Biney, M. T. Hepworth, K. J. Reid

The kinetics of gold-bromide loading onto activated carbon was investigated in a batch stirred reactor. Based on a second-order equation, the amount of gold adsorbed by the carbon was correlated with time. From a 30ºC solution containing 25 ppm Au and 0.8 g/L carbon, the rate constant for gold-bromide species onto activated carbon ranged from 0.27 x 10-3 to 1.2 x 10-3 (kg/t)-1 min-1. The equilibrium saturation capacity (Qe) was 36 ±3.0 kg/t from the same system. The rate of loading increased with increasing temperature and decreasing particle size, pH and solution gold concentration. The calculated activation energy (Ea) was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Qe) increased with increasing concentration of gold in solution but was independent of other variables such as temperature, agitation speed, particle size and pH. These rate constants and equilibrium saturation capacity for the gold-bromide species are higher than those reported for the gold-cyanide systems.

Jan 1, 1998

By C. M. Flynn

The Bureau of Mines prepared and investigated xanthated sawdust adsorbents to determine their effectiveness in removing heavy metal ions from dilute aqueous solutions, mine-drainage waters, and brines. Stripping of the metal values from the metal-laden adsorbent was also investigated. The treated sawdusts had an adsorption capacity of 0.3 to 0.4 meg/g dry adsorbent for Mn, Co, Ni, Cu, Ag, Zn, Cd, Hg, or Pb from feed solutions with pH 5 to 6. The feed solutions tested included mine-drainage waters and geothermal brine. Effluent metal concentrations as low as 0.05 to 0.1 mg/l were obtained at effluent pH values of 6 to 9. The order of affinity of metals for the sawdust adsorbent is Na«Ca~Mg~Mn<Zn<Ni<Cd<Pb~Cu. The presence of Ca, Mg, or Na in concentrations as high as 2 g/l does not seriously impair the heavy-metal adsorption. Metals were desorbed from the metal-laden adsorbent by elution with dilute mineral acids, sodium cyanide, or salts of ethylenediaminetetra-acetic acid.

Jan 1, 1979

By Eupene GS, Cheong GE

Operations at the Mount Bonnie gold/silver project are described. The project is based on the gossan of a stratiform and stratabound polymetallic sulphide deposit. The gossan contains approx- imately 100 000 tonne of ore grading 8g/tonne Au and 230g/tonne Ag. This is mined in an open cut, and transported to a stockpile area lkm away, from which it is fed to the treat- ment plant. The ore is crushed through two stages and fed to a fine ore storage shed, from which it is reclaimed, milled and cyanide leached in draft tube agitators. The pulp is filtered using a horizontal belt filter to recover a pregnant solution. Silver sulphide is precipitated using sodium sulphide solution, and collected as a mixed sulphide/precoat concentrate on a drum filter. The solution is then passed through carbon columns where the gold is adsorbed and is subsequently recovered by methanol desorption using a process developed by Micron Research, and electrowinning. Modifications to the treatment plant circuit based on operational experience are Described.

Jan 1, 1984

By P. L. Drake

This paper comprises a discussion of the role which mineral resources will play in Canada&apos;s future export trade and the growing demand for minerals in Canada.

Jan 1, 1979

By H. Conrad, K. Jung

"The effect of an external electric field E=5(+) kV/cm applied during the solution heat treatment at 500°-550°C of three commercial Al-Mg-Si alloys (AA6061, AA6022 and AA61l1) on the asquenched resistivity Pw and hardness H.,NULL, w was investigated. It was found that the field gave a significant increase in Pw and in Hv,w, for AA6022 and AA6111, but had no clear effect on AA6061. Thermodynamic analysis gave that the effect of the field on AA6022 and AA6111 was to reduce both the enthalpy ?H, and entropy ?H, of solution. Considering the chemical composition of the three alloys it appears that the influence of the field may depend on the amount of Cu plus excess Si present in the alloy.IntroductionKlypin and Soloviev [1, 2] were the first to report that the application of an external electric field during solution heat treatment (SHT) of Al alloys gave an increase in the as-quenched resistivity and hardness. They attributed these effects of the field to an increase in solubility of the alloying constituents during the SHT. More recently Liu and coworkers [3, 4] also reported an increase in the as-quenched resistivity of Al-Li alloys with application of an electric field during SHT. Further, the present authors [5] found that the application of an electric field during the SHT of the commercial Al-Mg-Si alloys AA6022 and AA61i1 increased their as-quenched resistivity and hardness. Their thermodynamic analysis of the results indicated that the field decreased both the enthalpy ?H, and entropy ?S, of solution."

Jan 1, 2004

By R. Bhaskar

The control of respirable dust in mines has been given paramount importance due to the health and safety implications associated with fine dust. The understanding of the temporal and spatial behavior of dust has been recognized as essential for increasing the efficiencies of the existing control techniques and for developing new control strategies. Mining-related studies in this area are, in general, limited. They are also mostly experimental. Some mathematical and computer analyses have been attempted. In this paper, first a review of the mathematical studies performed in the last three decades in this area is presented. Second, a mathematical model for analyzing dust flow in mines is proposed. The model takes into account a number of factors affecting dust transport. It incorporates varying dust generation source strengths and dispersion, deposition, and coagulation of dust in mine airways. Finally, application areas for the model are discussed. A computer program based on the mathematical model has been developed. The program will output the dust concentration in the mine atmosphere as a function of time and distance from the source. The amount of dust deposited on the sides, roof, and floor of the airway is also determined.

Jan 1, 1985

By H. J. Ramey

A general solution is presented for the transient temperature distribution caused by radial movement of a cylindrical heat source through a homogeneous medium of infinite extent. This problem represents a highly simplified model of the movement of a combustion front during the thermal recovery of oil. Numerical solutions are presented for a heat source moving at a constant velocity, and a velocity inversely proportional to the radial location of the heat source. Numerical solutions are presented for both finite and infinite vertical thickness of the heat source, i.e., with and without vertical heat losses. The numerical solutions are used to estimate the fuel concentration needed to maintain a combustion front during the thermal recovery of oil. The sensible heat carried to the combustion front by the injected gas stream is discussed in regard to the fuel concentration. Numerical solutions for a heat source (combustion front) of finite vertical thickness indicate the field conditions that may be necessary to sustain the temperature of a combustion front above the ignition temperature of the fuel over considerable distances from an injection well. The results also have implications in regard to the quantity of heat required during ignition. The results of this computation apply to a highly idealized model of a thermal recovery process. But the results may be used as a guide in engineering consideration of the thermal recovery process. INTRODUCTIO N The thermal recovery of crude oil has received considerable attention since the publication by Kuhn and Kochl of laboratory and field tests of this method of oil recovery. Other publications2,3,4,5,6, since that time have dealt with various features of the thermal recovery of oil and have illustrated the extremely complex nature of this process. Vogel and Krueger7 described an electric analog computer designed to solve a moving heat source problem which was analogous to movement of a combustion front during the thermal recovery of oil. The heat source was maintained at constant temperature and was a cylindrical source of infinite height (no vertical heat loss) moving radially at either constant velocity, or at a velocity inversely proportional to the radial location of the heat source. Jenkins and Ramey2 presented analytical solutions to a similar heat conduction problem and pointed out the possible importance of vertical heat losses. The following presents a general solution to the transient heat conduction problem introduced by Jenkins and Ramey4 as well as numerical solutions for a wide range of conditions possibly similar to those that might exist during field operation of the analogous thermal recovery process. DESCRIPTION OF PROBLEM The problem considered in this paper is determination of transient temperature distribution caused by a cylindrical heat source of infinite or finite vertical height, moving radially through an isotropic medium of infinite extent. It is further assumed that the heat flux generated at the surface of the moving heat source may be a function of time such that the fuel concentration required may be constant, or permitted to vary, and that heat is generated at the surface of the heat source only. In regard to the thermal recovery of oil the assumption that heat is generated at the surface of the front is equivalent to assuming that the thickness of the combustion zone is infinitely small, or that the reaction rate between fuel and oxidant gas is infinite. The last assumption does not appear stringent. See laboratory information published by Martin, et al3 Under these assumptions the temperature distribution throughout an infinite medium caused by a heat source moving radially with an arbitrary velocity may be described by The heat generation function or heat flux at the surface of the source, +(t), is Note that the fuel concentration may be defined as a function of time. Eq. 1 is derived in the Appendix.

By S. D. Dladla, S. Ramsamy

The majority of the tailings dam operations in South Africa will be required to comply with the new Global Industry Standard on Tailings Management (GISTM) within the next one to three years, depending on the dam classification and the requirements of the respective investors and insurers. With up to 72 auditable requirements, the implementation of the Standard needs careful planning and prioritization. This paper focuses on the practical steps to GISTM compliance for tailings facilities in operation in South Africa. The discussions are based on current practices, South African regulations, and industry standards requirements. The possible changes in dam classifications and the associated requirements are presented.

Jun 2, 2022

By J. H. Pee, Y. J. Kim, H. U. Lee, G. H. Kim

The general recycling process of tungsten scrap to produce tungsten raw materials (tungstic acid, ammonium paratungstate (APT) and WO3) have been carried out by the oxidation, milling, sodium-fusion, dissolution, and extraction processes. Many studies on the high temperature oxidation of tungsten scrap have investigated various aspects such as swelling kinetics, fracture resistance, and the effect of alloying composition. However, the accelerating factors on the scrap oxidation rate during oxidation were not considered here. In general, oxidized products were fused with sodium carbonate or sodium hydroxide to produce Na2WO4. Later in the process, solid Na2WO4 was dissolved in water. This process required considerable reaction time and was a costly process. Therefore, the aim of this study was to increase the solubility of solid oxidized products to produce Na2WO4 solution by hydrothermal reflux method. Na2WO4 solution was used to produce CaWO4 and H2WO4 by general chemical reactions with calcium chloride and hydrochloric acid. Ammonia solution was also added to the tungstic acid to produce APT. In this study, the effect of ammonia addition on the APT precipitation process was investigated in detail.

Jan 1, 2015

By Minji Jun

Leaching of the surface-coated metals from waste acrylonitrile butadiene styrene plastics (WABSP) has been investigated in the ammoniacal solution. The ammoniacal leaching of WABSP (typically containing 4.1 wt% Cu, 1.3 wt% Ni, 0.03 wt% Cr) efficiently dissolved copper and nickel, leaving unleached chromium as fine particles. The results indicate that the anions of different buffer media for metals leaching follow the order: CO3 2− > Cl− > SO4 2−. A declined leaching with high NH4OH–(NH4)2CO3 ratio (8:1) and a steep rise in extraction with high pulp in solution revealed the influence of anion (CO3 2−) and cation (Cu2+) present in the system. The leaching performed in carbonate solution by maintaining 5.0 M total NH3 concentration as NH4OH–(NH4)2CO3 ratio, 4:1; pulp density, 200 g/L; agitation speed, 400 rpm; temperature, 20 °C and time, 120 min yielded the maximum extraction (>99%) of copper and nickel. The study reveals a plausible recovery of the surface-coated metals from the WABSP without altering the properties of polymer material that can be recycled separatel

By W. J. Wolfe

"THE DETECTION OF BURIED MINERAL DEPOSITS by chemical analysis of vegetation (biogeochemistry) or visual observation of plant cover type (geobotany) is based on fundamentally simple principles. The root systems of vegetation collect aqueous solutions from a large volume of moist ground below surface and act as efficient sampling mechanisms by providing a composite sample of a reasonably large area. These aqueous solutions constitute a source of ore-associated metals that may ultimately be concentrated in the upper parts of the plant. Although certain plant species have a limited ability to break down primary minerals and extract elements, biogeochemistry normally detects only metals capable of moving in solution. Metal concentrations in the underlying soil must therefore exist in a form that is immediately available for uptake by the root systems - generally in the ionic state in aqueous solution or in readily exchangeable form on the surfaces of soil clay minerals. As a result, biogeochemical responses are closely related to variables such as soil pH, Eh, exchange capacity and complexing agents that control metal mobility in the surface environment. In terms of cost, reliability and anomaly contrast, soil geochemistry will normally be more useful than biogeochemistry in locating buried mineralization in regions of residual overburden or thin transported cover. However, in areas where the root systems penetrate thick deposits of transported post-mineralization overburden, plants can provide an effective mechanism of sampling below the transported material. Biogeochemical research in Canada, Scandinavia and the U.S.S.R. has therefore focused on the potential use of plant prospecting methods (1) in areas where the upper horizons of podzolic soils do not provide an adequate response to anomalous conditions under thick deposits of glacially transported till and (2) in widespread regions of peat and muskeg terrain where near-surface mineral soils are absent."

Jan 1, 1971

By R. B. Elver

The St Lawrence Seaway, a deep-water canal system between Montreal and Lake Ontario, was opened for navigation on April 25, 1959. Prior to the opening of the new Seaway, small boats known as canalers and a few deep-sea carriers, primarily from Norway since World War II, were the only ships able to journey past Montreal into Lake Ontario through the old Canadian St. Lawrence canal system. Thus it was necessary for many tons of bulk and general cargo to be shipped all-rail to and from Atlantic ports or to be transhipped to and from canalers. With the opening of the new Seaway, large Great Lakes bulk carriers and a much larger percentage of the world&apos;s shipping fleet are now able to sail directly from the sea to the heart of industrial North America. In this paper, the historical events leading up to the construction of the Seaway and the physical nature of the Great Lakes transportation system are briefly reviewed. Following this, an attempt is made to evaluate the effects of the new Seaway on Canada&apos;s mineral industry. Because the Seaway has been in operation for only one season, this paper must be considered only an interim report. Because of the importance of the Seaway to iron ore, this commodity will be dealt with in detail, although the effect on other mineral commodities such as coal, petroleum, nonferrous ores, iron and steel will be mentioned. At this time the author wishes to thank the various company and government officials who provided both factual information and critical opinions.

Jan 1, 1960