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There is an increasing demand for refrigeration as mines progress deeper. Mine refrigeration plants have special requirements in terms of their duty and application. There are no national or international standards applicable for the testing of these plants. There have been numerous examples of plants failing to meet their required nominal capacity, but with the plant owner being unable to enforce the design duty on the manufacturer, due to a failure to unambiguously specify testing or accepting criteria. This paper discusses some of the reasons for performance shortcomings and describes a methodology for developing and specifying performance criteria, when inviting design and/or construction tenders, and a method of performance and acceptance testing once the plant has been built and commissioned. These guidelines encompass the full range of performance duties expected from a mine plant, including stable operation at maximum and minimum plant capacity, and under the various combinations of extremes of high and low condensing and evaporating pressures. A description of a methodology for developing a computer-based mine refrigeration plant model is also presented as part of the performance testing criteria. The methodology is illustrated with reference to the actual performance and acceptance testing process used on the worldÆs largest bulk air cooler (R67) at the Enterprise mine at Mount Isa, Australia.

Jan 1, 2005

By B Delaney

For worker safety, mining companies are required to stop production and inspect hoist ropes. Visual inspection is generally done daily and EM inspection occurs every three to four months. During visual inspection, rope speed is generally reduced so an inspector can look for problems. In EM testing the LMA and LF traces are printed on a paper strip chart and a skilled operator interprets these traces. Mining companies only find large defects during visual inspection and are sometimes concerned about the content of EM trace information. This paper will present research outcomes that show how muck can be hoisted while performing a complete visual rope inspection at full speed. Other research results will show that digital signal processing can increase the amount of information available to the EM rope inspector. The research was funded by Inco, C-CORE, three AMIRA International sponsors and six sponsors from the Canadian Deep Mining Research Consortium (DMRC). The research will be commercialised in 2005.

Jan 1, 2005

By G. Baldermann, Hüttenrauch

Occupational health and safety are an important tool to increase a company’s economic efficiency. The integration of safety-related tasks into the overall structure of entrepreneurial tasks is an inalienable requirement for the sustainable achievement of positive effects. Investments into technical and personnel occupational safety that are tied in a streamlined organizational structure guarantee the improvement of defined indicators. The labor force is of central importance. Its added value ought to be ensured. It is necessary to move away from the employees‘ hazard awareness towards a safety awareness including many other aspects in order to save costs in the long run.

Jan 1, 2005

By Kokichi Iizasa

Two major Kuroko-type deposits and minor sulfide deposits have been found in the middle Izu-Ogasawara (Bonin) Arc, Japan (Fig. 1). The Hakurei deposit, one of the major Kuroko-type deposits, was recently found in Bayonnaise knoll caldera in the nascent rift zone, which lies 20 km westward of the Sunrise deposit in Myojin knoll caldera on the Izu-Ogasawara volcanic front. The Hakurei deposit is a huge hydrothermal field measuring 500 m by 700 m in plan view. The Bayonnaise knoll caldera is mainly composed of dacite lavas and fragmental material on the caldera wall and rim, and its floor contains sediment composed of pumice, volcanic fragments, and hydrothermal clay. It is associated with a post-caldera dome and has a slightly ellipsoidal caldera rim that measures 3 km by 2.5 km, with about 200 m relief. The water depths of the caldera floor range from about 840 m to 920 m. The Kuroko-type deposit in the Bayonnaise knoll caldera occurs on the southeastern caldera floor where the caldera boundary faults intersect with a N-S-trending normal fault of the rift zone. In the deposit, many sulfide chimneys are generally less than 10 m high, and sulfide mounds are distributed around the caldera floor and on the sloping talus at the foot of the caldera wall. The deposit is buried in part by talus composed of pumice and volcanic fragments. Sulfide chimneys are still active, and inactive ones and their fragments are partly oxidized to reddish material. Chimney sulfides are mainly composed of sphalerite associated with chalcopyrite, galena, pyrite, and barite, and chemically enriched in Au up to 14 ppm and Ag up to 1400 ppm with major Zn, moderate Ba, and minor Pb, Hg, Cu, and Fe.

Jan 1, 2005

By Alaina B. Hanlon

Keywords: Undercooling, Convection, Dendrites, Stainless Steel, Levitation Certain Fe-Cr-Ni stainless steel alloys solidify from an undercooled melt by a two-step process in which the metastable ferrite phase forms first followed by the stable austenite phase. Recent experiments have shown that the lifetime of the metastable phase is strongly influenced by flow within the molten sample. The current research will provide insight to why flow affects the metastable phase. This new understanding will lead to the use of convection to control microstructural evolution in spray-forming of stainless steels. Simulations using a commercial computational fluid dynamics package, FIDAP, yield a range of convective flow velocities that cause mechanical damage to the dendrites which is compared to experimental results. If the convective velocities are great enough that the dendrites bend, then low angle boundaries form at the points of collision. These result in high energy sites that could serve as nuclei for the stable phase.

Jan 1, 2005

By Pengfu Tan

A program ?SlagVis? has been developed to simulate the liquidus temperature, phase compositions and viscosities of ZnO-CaO-SiO2-Al2O3-?FeO? slag, such as Imperial Smelting Furnace (ISF) slag and lead blast furnace slag, combined with F*A*C*T slag database and the mathematical model of slag viscosities based on a modified Urbain formalism. The modeling results have been validated by a number of measurements. The effects of slag compositions on viscosities of ISF slag and lead blast furnace slag have been simulated and discussed.

Jan 1, 2005

INTRODUCTION This paper was originally presented at the Platinum Adding Value Conference, held at Sun City from the 4th to 6th October 2004. Narrow reef mining may not be applicable to the base metal operations in Zambia, however, it is considered that the methodology used is equally appropriate to the development of technology and mining methods in mining environments other than narrow reef mining. The purpose of this paper is to explore the integration of technology and stoping systems. For the last hundred years the South African narrow reef mining industry has battled to control working costs in a labour intensive industry. It is only through the application of appropriate technology that change will occur. Stoping systems, because it is the stoping method and methodology that is at the heart of the mining system. Introduce a different technology that results in a more efficient stoping system and the mining system will look after itself. The technology applied to stoping in narrow reef mining, over the last 100 years, can be categorised as follows: ? The introduction of pneumatic rockdrills early this century. The cumbersome rig mounted units being replaced by smaller, lighter, hand held units that were then made easier to use with the addition of an air leg. (The so called Swedish method of mining.) As late as the early 1970s some drilling was still being carried out without the assistance of an air leg. ? Scraper winches to replace gravity and shovels to move rock both in the face and the gullies were first introduced in the late 1920s. ? Hydraulic props installed close to the face and capable of applying force against the hangingwall as well as yielding in a controlled manner under dynamic load arrived in the 1960s. In many instances these have now been replaced by yielding elongates fitted with water hydraulic tensioning devices. ? Some people argue that the introduction of tungsten carbide inserts, to improve drilling, was equally important.

Jan 1, 2005

By R. Y. Wan, J. D. Miller

Thiohydrometallurgical systems including thiosulfate, thiocyanate and thiourea have been stud- ied as alternative liriviants for the leaching of gold. Research and development of thiohydrometallurgical technology has been prompted by environmental concerns with the use of cyanide and problems associated with the processing of difficult-to-treat ores. These thiosystems have some chemical similarities, enabling gold to be leached in a practical oxidizing environment. However, the solution chemistry of the thiosystems is complicated due to instability of the thioreagents and many other reactions which occur during the gold leaching reaction. In this paper, interference reactions of selected metal ions and sulfide minerals are examined in order to understand important aspects of solution chemistry which control the stability of the thioleaching reactions. Applications using thioreagents as lixiviants for oxide and refractory gold ores are presented.

Jan 1, 2005

By G B. Arehart

The Midas epithermal system is one of the larger low-sulfidation epithermal vein systems discovered in the western US in recent years, containing in excess of 3 Moz of gold (premining). The deposit is spatially and temporally related to bimodal volcanism in the Northern Nevada Rift; dates on igneous rocks (16 - 14.7 Ma) bracket the age of high grade veins (15.3 Ma). Hydrothermal alteration at Midas is typical of epithermal systems, comprising proximal potassic through distal propylitic assemblages; in contrast to many epithermal systems, Midas has minimal development of wallrock illite/sericite. Mineral assemblages are clearly zoned on the vein structures that acted as focal planes for fluid upflow. Geochemical zoning patterns also show this zoning. Metals were deposited in open-space veins as the result of boiling of hydrothermal fluids; multiple episodes of crustiform mineral deposition are documented in the vein textures. The major vein minerals include quartz, adularia, calcite, selenides and sulfides, with electrum as the primary ore mineral. REE patterns for vein material are similar to patterns for coeval rhyolites, but distinctly different from patterns of the host rocks. Stable isotope data are consistent with meteoric water as the dominant ore fluid. Combined REE and stable isotope data suggest that fluid from which the main ore-bearing stage of the veins was deposited was slightly lower pH than other stages.

Jan 1, 2005

By Shu Yan

The high resolution resistivity method (HRRM) is developed specifically for detecting underground cavities and tunnels. HRRM has a special feature in that it can recognize and cancel static shift, which makes it different &om the high density resistivity method (HDRM). In searching for various means for detecting underground cavities, we found that the detecting depth of the transient electromagnetic field method (EM) depends mainly on the measurement duration, not the loop area. In addition, TEM can also be used to locate the high-resistivity bodies. In order to use them for local working site conditions, we combine HRRM with TEM to become a combined electromagnetic method. Since the late 1980's this method has been used to locate abandoned mines and air passages and burning centers of mine fires with great success. This paper cites case studies for which this technique was successfully used.

Jan 1, 2005

By Craig Compton

The The National Institute for Occupational Safety ane Health (NIOSH) Pittsburgh Research Laboratory (PRL) is continuing to investigate the behavior of fully grouted roof bolts in the weak roof rock of the Safety Research Coal Mine (SRCM). This paper describes the results of three studies: A series of 24 pull tests of bolts installed fully grouted and overcored to leave 12 inches of grouted bolt. The tests compared the pull-out performance of offset-head roof bolts with that of standard 518-inch bolts; A second series of 24 tests that compared the pull-out loads obtained by bolts installed with 1 R of resin (a Short Encapsulation Pull Test or SEPT) to that of fully grouted bolts overcored to leave only 12 inches of grouted bolt, and An investigation into the pressures generated during the installation of fully grouted resin bolts. All of the bolts installed and pulled were overcored and removed from the roof after the pull tests to allow inspection of the resin. The first study found that there was no significant difference in pullout load between the offset-head bolts and the standard bolts. The second study, comparing the SEPT bolts and the partially- overcored fully grouted bolts, indicated that SEPT can significantly underestimate bolt anchorage grip factor, suggesting that the SEPT is a conservative measure of actual bolt performance. Significant loss of resin to cracks in the roof was observed in the bolts overcored in the SRCM. The third study explored one possible explanation for the resin loss, high pressures generated during bolt installation. These tests employed bolts installed in strain gauged steel tubes. The results confirmed that significant pressures (greater than 4,000 psi) can be generated during bolt installation. The results of the pressure tests, combined with the observations of resin loss in bolts installed in the SRCM, suggest that under some circumstances resin loss and under-encapsulation could take place and lead to degraded bolt performance. Glove fingering was observed in all recovered bolts to various degrees. The limited comparative data suggested that the effect of glove fingering ranged from slight to moderate. Complete mixing of the resin was observed on all of the 40 bolts recovered (28 fully grouted and 12 SEPT). Australian and U.S. resins were compared and the Australian resins were observed to have much smaller catalyst compartment areas and lower resin viscosities. These differences are suggested as potential explanations for occasional resin mixing problems noted in Australian resin bolt installations.

Jan 1, 2005

By Sanjeev Malhotra

"This paper presents the results of a pile installation monitoring and performance assessment program for pile foundations supporting 14 piers and 2 abutments of the 1700-ft long bridge crossing over a river in Baltimore, Maryland. Dynamic measurements were conducted during installation and restrike of 16 test piles, one at each support location. The foundation piles were 30-inch diameter, 0.75 inch thick pipe piles at the piers and 24-inch diameter, 0.5 inch thick at the abutments. The piles at the piers were approximately 100 ft long and were designed to carry 260 kips service load with a factor of safety of 2.25. The piles were driven open ended into a variable site stratigraphy containing recent deposits of organic clayey silts near the mudline followed by loose to medium dense sand, with some silt, and then by soil deposits from the Cretaceous period consisting primarily of dense to very dense, poorly to well graded sands and gravels and cobbles, with occasional seams of very hard to very stiff, low to moderate plasticity silts and clays. This paper presents the approach taken to evaluate the driven index piles and to develop criteria for driving production piles. It provides the Engineer with some data on pile driveability in Cretaceous soils in the Baltimore area, soil set-up effect, and an estimate of pile capacity.INTRODUCTIONThe typical approach to pile foundation design and construction should include an indicator pile program with dynamic measurements and a static load test program. However very often paucity of funds and schedule constraints cause an owner to do away with conventional static load testing which can take $25,000 to $100,000 and several weeks per test. This paper examines an alternate (though not equivalent) truncated approach to foundation assessment and presents a case history where this approach was implemented.Dynamic measurements were conducted during pile installation for the 14 piers and 2 abutments of the new 1700-ft long bridge over a river in Baltimore, Maryland. Strain transducers and accelerometers were attached to the pile top during initial driving and restrike of 16 pipe piles. The foundation piles consisted of 30-inch outside diameter, 0.75-inch thick pipe piles at the piers and 24-inch outside diameter, 0.5 inch thick at the abutments. The piles were driven open ended into a variable site stratigraphy. The approach taken to assess the foundation performance included 1) a pre-field wave equation driveability analyses, 2) field pile driving measurements, 3) post-field Case Pile Wave Equation Analyses (CAPWAP), and, 4) revised wave equation analyses based on field and CAPWAP data. The following sections describe in greater detail each of the steps taken to assess foundation performance and the results obtained."

Jan 1, 2005

By Joseph Gildner, Donald J. Phelps, Jürgen Laubbichler, Christopher Tattersall, David McAllister

The Beacon Hill Station and Tunnels portion of the Sound Transit Central Link Project consists of one mile of twin rapid transit tunnels, an underground station, portals and ancillary works constructed in an urban environment. Presently under construction, the station will set a number of North American firsts including deepest soft ground excavation carried out using the Sequential Excavation Method (SEM).Located in highly variable glacial soil deposits ranging from soft, water bearing sands to stiff, slickensided clays, the station complex and running tunnels proved to be technically challenging during design. Meeting these challenges necessitated an extensive geotechnical investigation, a trial shaft, and state-of-the-art numerical analyses to develop ground conditioning, pre-support, excavation support and structural design. A comprehensive risk identification and mitigation program, and innovative procurement strategy were incorporated into the design and contract bid documents.

Jan 1, 2005

By R. Ressel

Keywords: ferrovanadium, thermodynamics, phosphorus Recyclable material is rapidly gaining in importance as a source of raw materials in industrialized countries. This is also the case in the production of ferrovanadium, where, increasingly, materials such as discarded capacitors, spent catalysts, slag, dust and sludge are used. As the V-content in the raw material varies greatly, the demands on process technology are very high. The share of perturbing elements depends very much on the source of the raw materials, which, in turn, makes a corresponding optimization of the various refining steps necessary. The raw materials are mostly available as oxides, which means that carbon, silicon or aluminium are used as reducing agents. Thermodynamic calculations were used to show especially the behavior of vanadium and phosphorus at different process conditions.

Jan 1, 2005

By F. Figge, T. Hahn

In this article we present Sustainable Value, a valuation methodology to assess sustainable value creation of companies. Sustainable Development posits that decisions must not only take into account economic capital but also natural and social capital. Sustainable Value, the methodology presented in this paper, borrows the idea from financial economics that the return on capital has to cover the cost of the capital. Capital costs are determined as opportunity costs, i.e. the forgone return that would have been created by an alternative investment. By expanding the well established logic of the valuation of economic capital in financial markets to also cover natural and social capital we provide a methodology that allows an assessment of the most efficient allocation of economic, natural, and social capital for sustainable value creation in companies. We demonstrate the practicability of the methodology by the valuation of the sustainability performance of British Petroleum (BP).

Jan 1, 2005

By E. Czech

Hydrogen generated through aluminum-assisted water split reaction is a novel, efficient and environmentally friendly method. It has been found previously that the passivation of aluminum can be prevented in neutral (pH=7) or near neutral pH conditions in water by grinding aluminum with a catalyst, such as A12O3, SiO2 or SiC. Recently, the best results have been obtained by using water-soluble inorganic salts (WIS), ground with aluminum. The massive, rapid corrosion reaction of the Al-WIS system which takes place in regular tap (or marine, or ground) water can be utilized to produce hydrogen by aluminum-assisted water split reaction, in-situ, on-demand. The reaction offers clean, low-cost, environmentally benign and entirely recyclable technology for on-board on-demand hydrogen generation. Besides pure gaseous hydrogen, only pure solid aluminum hydroxides AlOOH or Al(OH)3 are formed as the reaction products. The hydrogen yield and Al-WIS reaction efficiency are high. From 1 g of mechanically alloyed aluminum powder, up to 1.25 liters of hydrogen were generated, i.e. efficiency up to 92% was achieved. The amount of hydrogen and hydrogen generation rate depend on various reaction parameters. The effect of chemistry and concentration of additives, water temperature, powder particle size and milling conditions on the reaction kinetics will be presented and the possible process mechanism will be discussed.

Jan 1, 2005

By J. Kulczycka

The concept of sustainable development is be-coming present in the policies of increasing number of industries and governments. The complexity affects not only production aspects, but has also special relevance for environmental decision making. Not only producers are re-evaluating the services they expect from the environment and concomitantly increasing their willingness to sacrifice other consumption in favour of enhanced environmental services, but the character of environmental issues is becoming more complex as well. Incomplete information, uncertainty, system wide change, trans-frontier impacts, current causes that have far reaching future effects, irreversibility, and possibilities of catastrophic change all complicate the environmental decision making process. Non-ferrous metals production, due to a relatively low level of metals content in ore, results in generating huge amounts of tailings, exceeding usually 90% of the mine output. They must be stored in special facilities, which have the significant impact on the environment both during tailing management facilities (TMF) operation and after their closure. One of the most essential impacts of operating and closed TMFs is their eolic activity, displaying in worsening air quality, aero-sanitary conditions in the neigh-boring villages and contamination of soils close to the facility by heavy metals.

Jan 1, 2005

By B R. Castley

Consumable materials used in mines are often transported to the working areas down shallow angle decline shafts, typically at anywhere between 10¦ and 30¦ to the horizontal. The winding equipment is usually a relatively small single-drum winder and the material is transported in one or more cars, running on rails in the decline. The winding rope is attached directly to the cars, which are mechanically coupled together. For small rock hoisting declines, the cars are replaced with hoppers or skips. The winder is normally of basic design, fitted with only the minimum required safety devices and very elementary brake control. Since these winders are not ælicensedÆ and are usually located in remote areas, the standard of maintenance on the installations is often poor, leading to frequent accidents, resulting in runaways, derailments and broken ropes. These problems can be overcome easily with the application of the rope haulage principle. When large volumes of ore have to be transported to surface, belt conveyors are used on shallow angle inclines, or high-capacity friction winders are used in vertical shafts. Conveyors are limited to inclines no steeper than 14¦ and vertical shafts with large friction or drum type winders are extremely capital-intensive. Rope haulage systems can be used on decline shafts where the inclination is too steep for belt conveyors and too shallow for conventional drum winders. Rope haulage systems also offer a variety of safety, technical and cost advantages over other winding and transport systems. This paper describes the adaptation of the rope haulage principle to modern requirements and, combined with 21st century electronic technology, explains how the principle can be used as an efficient, safe and practical solution to some problems associated with the transport of materials, personnel and ore in mines. The authors describe the designs, methods of operation, safety aspects, automated control, loading and unloading facilities of modern rope haulage systems used for transporting personnel, material and ore. This paper considers a variety of systems already designed for different applications, from small material-only installations to multi-purpose and large rock-hoisting systems with payloads as much as 180 t. It also describes in more detail, a material transporting system recently commissioned in South Africa.

Jan 1, 2005

By Thomas M. Barczak

The transverse loading requirement for stoppings as specified in the current Code of Federal Regulations is 39 psf. This measure is based on physical testing of a freestanding wall in accordance with ASTM E 72 specifications, where the dominant parameter is the tensile strength of the sealant. A new protocol based on arching has been developed to determine the true transverse load capacity of stoppings. Arching is achieved by the restraint of the stopping against the mine roof and floor, whereby compressive forces are developed within the wall. A laboratory procedure using the NIOSH Mine Roof Simulator (MRS) to simulate rigid-arching of stoppings was developed and verified through full-scale in-mine tests. Using this protocol, a systematic study of the design parameters that affect arching capability in block stoppings was conducted. The study included a theoretical assessment of arching and development of design formulations that can accurately define the transverse load capacity of various stopping constructions under various loading conditions. This approach should lead to a safer mine environment by matching the transverse load capabilities of the stopping design to the requirements in the mine to ensure proper ventilation control is maintained.

Jan 1, 2005

By A van As

This paper serves to outline the circumstances and causes of the air-blast that occurred at Northparkes Mines in November 1999. It describes the design of the mine, the geotechnical issues surrounding cave propagation and the cave monitoring systems that were in place prior to the event. A short description of the air-blast that followed a sudden collapse is given. Details of the risk assessment process that evolved during the rectification process are provided with their subsequent modification to form the core of a major hazard monitoring process. The system is in line with the recommendations given by the Coroner resulting from the inquest into the deaths of the four people who lost their lives during the air-blast.

Jan 1, 2005