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By Brook W. H

The history of the reduction of iron from its ores is lost in antiquity. Archreologists state that man has practised it for over four thousand years. Until comparatively recent times charcoal was the principal reducing agent for making metallic iron from its various oxidised ores. Coke was first used by iron founders in England in 1619, and its use spread gradually throughout the civilised world from then onwards. Indeed, the destruction of forests to obtain the requisite charcoal made the iron founders, both in England and America, extremely unpopular, and this hampered the iron industry to a considerable extent, until coal provided the metallurgist with a new and better fuel--coke which is used by most pyro-metallurgists today. The transition from wood to coal products for iron smelting had a profound effect on the location of iron works. Particularly was this the case in America where, in the infancy of the industry, practically each of the early States had its own iron producers, but as coal and coke replaced charcoal, there came about a concentration of the iron and steel industry around the coking coal deposits, and so today there are huge steel plants clustered around the soft coal basins in Pennsylvania and Illinois.The development of the iron and steel industry in Australia, which is comparatively recent by world standards, has been cradled in the coal basins of New South Wales. The first steel works of any consequence in this country were built near Lithgow, close by the mines which produced the coal for coking.Incidentally, these works were rather unique in that the three essential materials for iron and steel manufacture-ore, coal, and limestone-were found virtually at the works' back door.When, in 1912, the location of the proposed steel works for The Broken Hill Pty. Co. Ltd. for smelting ore from Iron Knob in South Australia was considered, the site ultimately chosen was at Newcastle, almost on top of seams of satisfactory coking coal. One of the major factors which had determined the site of the steel works was the fact that, about 1912, three tons of coal were required to produce one ton of finished steel product, and the relative economics of ore and coal haulage were much in favour of bringing ore to the coal.

Jan 1, 1947

By S. D. Normani

A Deep Geologic Repository (DGR) for Low and Intermediate Level radioactive waste has been proposed by Ontario Power Generation for the Bruce Nuclear site in Ontario, Canada. The DGR is to be constructed at a depth of about 680m below ground surface within the argillaceous Ordovician limestone of the Cobourg Formation. The objective of this paper is to apply paleoclimate boundary conditions to a regional-scale groundwater flow model for the DGR site and to describe the influence of glacial loading and unloading on flow system evolution using the FRAC3DVS-OPG flow and transport model. The regional-scale domain encompasses an area of 18,775km2 extending from Lake Huron to Georgian Bay in southwestern Ontario, Canada. From a hydrogeologic perspective, the domain can be subdivided into a shallow zone, an intermediate zone, and a deep zone comprised of the low-permeability units of Ordovician and the more permeable Cambrian where present. The deep groundwater zone is characterized by units containing stagnant water having high concentrations of total dissolved solids (TDS) that can exceed 300g=L. The high TDS values at depth require density-dependent coupled flow and transport calculations within FRAC3DVS-OPG. The computational sequence involves the calculation of steady-state density independent flow that is used as the initial condition for the determination of pseudo-equilibrium for a density-dependent flow system that has an initial TDS distribution. The 1,000,000 year pseudo-equilibrium heads and brine concentrations are used as the initial condition for the paleoclimate simulations. Over the past 900,000 years, the Canadian Shield has experienced approximately nine episodes of complete glaciation. During the glaciation cycles, the entire Canadian land mass has been covered by a series of continental ice-sheets whose maximum thickness reached 4 km and whose southern extents reached, in some cases, beyond the present-day Canada-U.S. border. The glaciation phase of a single glaciation-deglaciation episode is typically 90,000 years in duration, while the deglaciation portion proceeds relatively rapidly and has an average duration of approximately 10,000 years. Output from the University of Toronto Glacial Systems Model, a continental scale North American glacial reconstruction of the most recent 120,000 year glaciation event developed by W. R. Peltier, is used to supply the paleoclimate boundary conditions used in this paper. Permeabilty reductions due to the presence of permafrost are also considered in the paleoclimate simulations. This paper will demonstrate that the choice of rock properties can significantly affect residual pore water pressures within the rock matrix, as well as the migration of glacial meltwater.

May 1, 2009

By R. N. Torbin

Foster-Miller has recently developed a new concept.for a highly specialized shaft lining system. This innovative shaft lining system uses a continuous slipforming placement technique. lining the shaft from the bottom up such as in a raised bored shaft. Although this part is not unique, the concept is designed to use polyurethane foam instead of concrete for the liner material. Furthermore, the concept is designed to attain rates of advance of 30 m/hr. The polyurethane foam liner is designed to be thinner (100 mm) than a conventional concrete liner (300 mm). It will eliminate the high cost associated with the erection and operation of an on-site concrete batch plant. The system will be designed to be operated remotely, requiring few personnel for its operation. This system (or parts of it) may be appropriate where fast construction speed is required or where a jointless liner is needed.

Jan 1, 1988

By J. Michael Canty

Over 25 years of US research in Mineral Recovery from Geothermal Solutions have lead to few commercial applications. With the World Bank program in Kamchatka, Russia in September 2005 a step was taken to vitalize and coordinate the many efforts to advance economic mineral recovery systems worldwide. The US Department of Energy is helping to spur on the interest and research needed to realize the many benefits of extracting minerals from geothermal solutions. The excitement of recovery of minerals from geothermal brines has many positive angles. The economics of certain geothermal site is improved if a revenue is arrived from a sellable commodity with the geothermal power. The use of cleaner geothermal brines also improves the capable use of the brine before reinjection. We will review the history of Geothermal in the USA and the opportunities for recovery of different minerals and the markets for them.

Jan 1, 2006

By Joseph F. Peters

The paper will begin with the physical parameters of design in a wire saw. These will include such things as the type of wire used, abrasives, horsepower of operation, and drive components. It will then go into the many uses of wire sawing in the quarrying and finishing of granite. This will include a step by step program of the removal of a block unit of granite from the quarry site through the finished slabbing and jointing in the plant. After this, there will be a small insertion of possibilities of wire sawing techniques in underground excavation work. This would be speculative only. I will use the example of powerhouse type of excavation work given to me by Dr. John Reed, and try to explain how I would attack this type of work using wire saws. Several slides of both design criteria and actual installations were shown.

Jan 1, 1997

By Rod Knopp

Each year approximately 5,000 tons of a sulfide concentrate grading 1 ounce gold per ton are produced at this operation. The material is refractory and as shipping costs and custom smelter charges increase, options to process it on site are becoming more attractive. Three methods of treating the ore have been investigated in detail. The first option of ultra fine grinding the concentrate produces a 35% gold recovery with relatively low capital and operating costs. A second option of pressure oxidation is very capital intensive and has high operating costs but recoveries in the order of 95% are achievable. The final option, biological leaching offers both capital and operating costs which are less than pressure oxidation, while still achieving 90% gold recoveries. Bioleaching of gold concentrates has been gaining acceptance but there is a risk factor associated with this or any emerging technology.

Jan 1, 1990

By Harry M. Castrantas

Caro's acid (peroxymonosulfuric acid-H2SO5) is used to destroy cyanides in tailings slurries due to its rapid reaction and low capital and operating costs. Due to its instability, Caro's acid is generated at the mine site using a hot or cold process. The majority of gold mines that use Caro's acid use the FMC hot process. In the FMC hot process, it is not necessary to cool the Caro's acid to minimize decomposition since it is used immediately upon generation. In contrast, the cold process uses a chiller to cool the raw materials and product. This paper will show, using laboratory and field data, that there is virtually no difference in Caro's acid yield between the cold and the FMC hot processes. Caro's acid yield depends on the mole ratio and concentration of sulfuric acid and hydrogen peroxide and is independent of operating temperature.

Jan 1, 1997

By Harry M. Castrantas, James L. Manganaro, Craig W. Rautiola, James Carmichael

Caro's acid (peroxymonosulfuric acid) was successfully field tested as a cyanide detoxification agent at a North American gold mine. An on-site FMC generator injected Caro's acid into a mill tailings slurry sump. The WAD cN-(weakly acid dissociable plus free cN-) was reduced from 40-108 ppm to below the target level of 20 ppm using a 1/1 mole ratio of CA (Caro's acid) /CN-. At an inlet CA/CN-mole ratio of 1.8/1, WAD CN­concentrations as low as 4 ppm cN-were achieved. Raw material costs for the cyanide detoxification were cut by 60% compared to using hydrogen peroxide (H202) alone. Detoxification time with Caro's acid was much faster compared to H202. This resulted in completion of detoxification before the treated slurry reached the tailings pond thereby substantially reducing the probability of wildlife fatalities.

Jan 1, 1993

By M. Stefanakis

Respect for the people is one of the main values of S&B. Such respect needs to be manifested by actions ensuring the bodily and spiritual integrity of personnel in pursuing their work. The ultimate target is to achieve zero accidents by developing the culture and infrastructure required to support it. Within this framework, the following proactive safety practices were introduced in 2004 and are implemented at S&B Greek sites: (a.) Management Safety Visits (MSVs) of shop floor operations to address safety attributes of work guidelines, (b.) Monitoring compliance with critical work guidelines, using a ?safety barometer? tool. The proactive nature of both above systems, facilitates communication with employees on safety behaviors and their adoption in our facilities at Milos and Fokis, has been successful. Above all, these practices corroborate the management?s concern for the people and its commitment to continuously improve the working environment.

Jan 1, 2007

By Bob Butler

Brunswick Mine has been involved in a comprehensive research program investigating site specific aspects of thiosalt management to eliminate its adverse environmental effects. Minimum annual reagent cost estimates for thiosalt treatment using hydrogen peroxide and sodium hypochlorite are $400K and $1.5 million respectively. Also, minimum costs for the use of bicarbonate to buffer the pH depression associated with thiosalt oxidation in the receiving environment is in the order of $400K annually. A design of experiment (DOE) research program identified that natural UV radiation, temperature, DO and water chemistry are key factors influencing the natural oxidation rate of thiosalts within Brunswick?s water management system. A DOE surface response model was used to describe the thiosalt oxidation kinetics, which were then used to develop a predictive oxidation model for thiosalt and pH control of the mill?s reclaim water system.

Nov 1, 2002

By Wauchope AMH

Arsenic residues from BHAS Refinery operations are currently treated to form a calcium arsenic compound and stored in lined dams on site. Laboratory and large scale work on these residues has resulted in the development of a hydrometallurgical process for production of arsenic trioxide. The process also recovers the material from the storage dams. The residues are hot water leached to produce an alkaline arsenic liquor. This liquor is mixed with material from the storage dams and lime to form a calcium arsenic precipitate. The precipitate is then reacted with sulphuric acid to form gypsum for return to the main plant, and an acidic arsenical solution. Metallurgical gas containing 3-6% sulphur dioxide is bubbled through the solution and on cooling arsenic trioxide is precipitated. The product contains in excess of 95% arsenic trioxide. Installation of a plant at Port Pirie based on this process is being evaluated by BRAS.

Jan 1, 1984

By W. H. Jay

Sulphide-containing minerals, particularly iron, lead to acid formation. In turn, the acid generates effluents such as copper acid drainage (AMD). The Berkeley Pit in Butte, Montana, USA and Mt Lyell in Tasmania, Australia, represent just two of many sites throughout the world for which acceptable treatment methods are required. In the gold cyanidation process, the presence of copper creates both a significant cost impediment and a potential environmental hazard. The tailings dam failure at Baia Mare in Romania which led to the release of copper and zinc cyanides created a major environmental disaster. The application of non-toxic water soluble polymers and ion exchange resins to selectively recover copper from AMD solutions, and the in-plant treatment of copper cyanide solutions and slurries to recover copper and recycle cyanide to prevent cyanide entering the tailings impoundment will be discussed. The economics of the various processes will be highlighted.

Jan 1, 2003

By A R. A Gomes

The Metropolitan Rapid Transit Authority (MRTA) Initial System Project (ISP) - Underground Structures North, UGN, is the northern section of the blue line, which is the first stage of an underground mass transport rail system of 77 km to be implemented in the central area of Bangkok, Thailand. The UGN section (Huai Kwang - Bang Sue) consists of approximately 8 km of twin single track bored tunnels, nine underground stations and some short cut and cover tunnel sections. The paper focuses on the main issues involved in the structural design of the precast concrete lining, which is the definitive structural support of the bored tunnels. It includes an overview of the site and geotechnical conditions, specific properties of precast concrete linings, ground-structure modelling, approach for the assessment of load conditions and respective sectional forces and particulars of the detailing of the reinforcement and the segment testing program.

Jan 1, 1999

By John A. Shuster, Joseph A. Sopko

Construction of two shafts, as well as associated deep concrete structures, for a major storm sewer project in Milwaukee, Wisconsin required ground water control and temporary ground support to depths ranging from 19.2m to 55.0m. Lowering of the site ground water table eras not possible because of potential consequences for existing nearby structures. Construction entailed completion of two shaft collars into bedrock. In addition to the shafts, several adjacent connected. structures were completed. Ground freezing was selected to provide temporary ground support and ground water control for all excavations. The first application of using reinforced frozen earth was successfully incorporated on the project. The procedure enabled the contractor to create openings in excess of 9.1m in height, without bracing, through highly stressed frozen earth walls. Design features and construction procedures for completion of ground freezing and related excavation are reported.

Jan 1, 1989

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By G J. Kulbieda

The Empire Mine initiated production in 1963. Since then the unit operations of drilling and blasting have evolved continually in order to meet the increased mining requirements demanded by plant expansions in 1968, 1973 and 1980. Additionally, advance mine planning has become an integral part of proper pit development and is necessary to insure uniform blending of the distinct ore horizons contained within the mine area. Blasting practices have been modified to facilitate the autogenous grinding system utilized at Empire and pioneered in the Iron Ore Industry. Technical innovations in the explosives industry, as well as, progress regarding on site blast engineering methods have substantially increased the use of ammonium nitrate explosives and helped to establish efficient charging procedures. In addition, the recent introduction and use of ammonium nitrate fueled with nitropropane and methanol indicates that it is a viable substitute for aluminized ANFO.

Jan 1, 1981

By Alfredo P. Vargas

Industrial flotation of sulfide ores is 80 years old. It has gone through many advances to date. However most flotation operations are still struggling to improve performance, which as a worldwide average is at the 90% level. What can be done to push the ceiling to 95% or better without performing finer primary grind, nor without duplicating flotation plant capacity? Such "unique task" can be performed by the low volume high capacity new flotation equipment known as the JAMESON CELL, when used as, "post-scavenger" of final plant tails. Improved efficiencies are obtained mainly from two cases: -Particles which never contacted a bubble. -Particles sheared-off by cell turbulence due to reduced number of hydrophobic sites. The application reverses conventional trend of using large volume mechanical cells by trade-in with smaller efficient equipment: resulting in reduced capital expenditures and operating costs. Outstanding "pre-rougher" applications are also presented.

Jan 1, 1993

As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

By Lætitia H. Delmau

SXFIT is the latest in a series of programs developed in our group to model solvent extraction systems of increasing complexity. SXFIT permits the user complete freedom to define the constituents from which the composition of each phase is to be specified in the data and from which all species of a model for a system are assumed to be formed. Activity coefficients in the nonaqueous and aqueous phases, water activity, apparent molar volumes of aqueous species, and solution density needed for the conversion of concentration from the molarity to the molarity scale are all taken into account by the program. Several extraction systems relevant to nuclear-waste treatment were modeled successfully using this program. As an example, the cesium extraction efficiency of the CSSX process chosen by the USDOE for cesium removal from high-level waste stored at the Savannah River Site can be predicted correctly for varying feed composition.

Jan 1, 2003

Exploration of a coal deposit provides the data on which a range of mine plans can be developed during project feasibility. The stages of exploration use methods and procedures which initially outline the deposit with more detailed data gathering and analysis of the specific site complexities. The in situ coal resource and reserves are calculated. The mine plan is a function of the mining method chosen and can have significant impact on the recoverable reserves. Other factors which can impact on the recovery of the reserves and the ability to maintain planned production levels are those which were either undetected during exploration or were misinterpreted. Exploration programs should be detailed enough to minimise to an acceptable standard the recognised and potential risks. Past programs which explored to achieve a minimum exploration density required to satisfy measured reserve status have generally proven to be inadequate, placing reserves and production at risk.

Jan 1, 1997