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Multiple regression analysis was used to predict elemental concentrations of copper and nickel in soils from consideration of the concentration of these elements in vegetation in an ultrabasic complex in New Zealand. Regression equations were computed from sixteen independent variables involving concentrations of ten elements in plant ash, and various physical factors such as slope and altitude of the site, and height of the tree. One elemental and one physical variable were significant for nickel at the 90 per cent level of probability and five elemental and two physical variables were significant for copper at the same level. Use of the regression equations explained 32·5 per cent and 26·5 per cent of the variance in the respective relative accumulations (amount in plant divided by amount in soil) of copper and nickel.Predicted concentrations of copper and nickel in soils agreed more closely with the observed values in the soils than did the levels of these elements in plant ash.Although the results may specifically apply only to the test area, the principles should have universal application.

Jan 1, 1972

In an earlier paper (Stanton, 1953) a brief account was given of the geological environment and structure of the Lloyd Copper Mine orebody, Burraga, N.S.W. The present paper is concerned with the chemical and mineralogical features of the ore from this mine.Investigation has been made difficult because of inaccessibility of the workings, which have been fallen in for many years. The exact positions within the orebody of the specimens described in this paper are known in only a few cases. The specimens examined are from the collections of the Mining and Australian Museums, Sydney, and from material collected by the writer from the upper parts of the mine and from various dumps about the old workings.However, no significant variations in the nature (as distinct from grade) of the ore have been mentioned in the old reports, or by Carne (1908) or Kenny (1928), so it is likely that the specimens examined are reasonably representative of the orebody as a whole.CHEMICAL CONSTITUTIONThe ore is of simple and apparently very uniform composition.It is essentially a copper ore, with minor amounts of zinc and very minor amounts of lead. Plotting of copper against zinc shows a more or less sympathetic relationship between these at least as far as 20 per cent. copper - the highest grade assayed during the present investigation. The trend of the plots indicates a Cu/Zn ratio of about 15/1 to this point. Lead is very low and extremely sporadic, showing no clear relationships with the other metals.MINERAL COMPOSITIONThe principal non-opaque minerals are quartz and sericite, and these are accompanied by smaller quantities of muscovite, calcite and biotite. Quartz is the most abundant mineral, occurring both as a C'onstituent of the country rock a quartz-sericite schist-and as veins. All quartz aggre...

Jan 1, 1955

By Jose Luis Sosa, Marco Surichaqui, Ramirez Marcelino

El proyecto permite obtener resultados de operación que no siempre son los esperados en cuanto a calidad y recuperación, aquí es donde destaca el programa; tiene una data que PRONOSTICA estos resultados, con el control de parámetros, corrigiendo estos resultados al valor óptimo esperado, haciendo que su empleo permita obtener en “tiempo real” excelentes resultados en cuanto a calidad y recuperación del licor lixiviado y se refleja en costos.

Sep 1, 2017

A Novel Diagnosis and Evaluation Procedure for Flotation Plants

Sep 13, 2010

The suitability of char from Yallourn brown coal as a filler for carbon electrodes used in the aluminium smelting industry has been assessed on the basis of the specifications usually laid down by electrode manufacturers for petroleum coke fillers. The purity specifications can be met by a simple acid leaching of the coal before carbonization. The true density of char produced at 1200°C is within 5 per cent of the specification figure, but the bulk density of char obtained from as-mined coal is only half that specified for petroleum coke.Although this can be increased to three-quarters of the specified figure by briquetting the coal before carbonization, further increases would be very difficult to achieve, as the remaining shortfall in density is due to an extensive microporosity developed in the particles of char during carbonization.

Jan 1, 1970

By S C. Dominy

The grade of ore at Marvel Loch mine is directly related to the presence or absence of shear zones and quartz-sulfide-rich hornblende (¦ diopside) veining within areas of plagioclase alteration. An experienced geologist can identify these features in hand specimen. Practical rules have been developed to assist this visual identification. The structural sites and styles of alteration and veining most conducive to gold mineralisation have also been determined. The work has enabled a better understanding of the geological controls on mineralisation at Marvel Loch, and has clarified geological understanding for optimisation of grade control modeling, ore block mark-ups, and minimisation of ore loss and dilution during excavation. In addition to this, it has enabled a detailed understanding of mine scale structural controls, geometry and relative grade relationships.

Jan 1, 2003

By L. Malmgren, A. Ansell

This paper deals with the influence from blast induced stress waves on the performance of shotcrete support in the Kiirunavaara mine. Time histories of stress waves from blasting were obtained from measurements during production blasts in the mine, followed by failure mapping. A finite element model, consisting of beam and spring elements, was used to calculate the shotcrete response to vibrations from blasting. The modelling approach was similar to that of a building during an earthquake, with accelerations measured in-situ used as loads. The analysis showed that the calculated adhesive stresses exceeded the strength in the interface between rock and shotcrete near to the blasted ring. It also indicated that tensile rock failure did occur. These types of failure will presumably result in ejection of joint defined rock blocks or rock slabs and will require a ductile support, such as fibre reinforced shotcrete. The predicted failure was confirmed by the mapping, which also showed that the zone of failed shotcrete was much larger in areas with plain shotcrete compared to areas with reinforced shotcrete. L’influence de l’onde de pression générée par les sautages à la mine de fer de Kiruna sur la performance du béton projeté est étudiée dans le présent article. Les ondes créées par les sautages ont été enregistrées et les domages résultants ont été cartographiés. La réponse du béton projeté aux vibrations de sautage est étudiée à l’aide d’un modèle d’éléments finis, constitué de poutres et de ressorts. L’approche est similaire à celle d’un immeuble subissant un tremblement de terre, avec les accélérations internes utilisées comme charges. L’analyse montre qu’à proximité des sautages, la contrainte adhésive dépasse la résistance de l’interface roche-béton. L’analyse confirme aussi l’existence de ruptures en tension. Ces types de rupture induisent probablement l’éjection des blocks définis par les structures du massif rocheux et requierent un support ductil, comme du béton projeté renforcé par exemple. Le type de rupture est confirmé par les observations de terrain, qui montrent aussi une extension plus importante des domages lorsque le béton projeté n’est pas renforcé. In diesem Konferenzbeitrag geht es um den Einfluss, der aus einer Sprengung hervorgerufenen Schwingungswellen auf die Ausführung der Spritzbetonverstärkung in dem Kiirunavaara Bergwerk. Die Aufzeichnungen der Schwingungswellen von Sprengungen gemäß einer Fehlerkartierung beziehen sich auf Messungen, die während der Sprengungen durchgeführt wurden. Ein Finite Elemente Modell, bestehend aus Stab- und Federelementen, wurde für die Berechnung der Spritzbetondeformation in Bezug auf die Schwingungen aus Sprengungen angewendet. Die Modellierungsmethode war ähnlich der eines Gebäudes während eines Erdbebens anhand der gemessenen Beschleunigungen vor Ort, die als Lasten benutzt wurden. Die Untersuchung hat gezeigt, dass die berechnete Haftspannung größer war als die Festigkeit in der Verbindung zwischen Gestein und Spritzbeton in der Nähe des Sprengungscentrums. Die Analyse hat gezeigt, dass die Zugfestigkeit des Gesteins versagte. Diese Arten von Versagen werden als Folge der Herausnahme von Gesteinsbrocken oder Gesteinsplatten erklärt und benötigen eine faserverstärkte Spritzbeton. Das vorausgesagte Versagen bestätigte sich beim Kartieren, welches auch zeigte, dass die Zone des versagenden Spritzbetons in Bereichen mit unverstärktem Spritzbeton viel größer war als in Bereichen mit armierten Spritzbeton.

Jan 1, 2003

By Richard Kastner, Emilie Vanoudheusden, Fabrice Emeriault, Jacques Robert

INTRODUCTION The subway line B of Toulouse (France) has been realized with three different tunnel boring machines (TBM) techniques: Contracts 2 and 5 are excavated with earth-pressure balanced TBM, Contract 4 with a slurry shield TBM, and Contract 3 with a compressed-air TBM. The first three machines are around 7.7 m in diameter, while the last one is 5.3 m. Moreover, a small part of the line (50 m) has been excavated by a conventional method. The tunnels run through the Toulouse molasses, composed of hard sandy clay with pockets and lenses of dense sand. Geotechnical investigations have shown that in these formations, K0 is greater than 1, around 1.8 at a depth of 25 m (Serratrice,2005) and that geotechnical characteristics are homogenous on the whole layout (? =22 kN/m3, Su = 300 kPa, c' = 30 kPa, F' = 32°). The water table is found between 2 and4 m below ground level. As geology, stratigraphy and tunnel cover (between 10 and 20 m) are almost identical, a comparison of movements induced by the excavation by each of the four excavation techniques is possible. This paper presents the soil mass movement measures in the case of the conventional excavation method and in the case of TBM sections. It shows how tunneling parameters may explain the different surface movements observed during excavation. For the sake of simplicity, only the results of Contract 2 (earth pressure balanced TBM)will be presented. MONITORING Monitoring for the Conventional Method Section For the conventional method section (Vanoudheusden et al. 2005) the mass soil movements are measured with two inclinometers and one multi-point extensometer borehole with automatic data acquisition (Figure 1). The monitoring devices include

Jan 1, 2007

By Ken Dyck, Chuck Edwards

"Cameco's McArthur River is the world's largest high grade uranium mine. Production started in late 1999. Cameco carried out the engineering design and construction management for the McArthur River project, including all aspects of mining, ore handling and ore transportation. The ore composition was expected to vary dramatically (0 to 30% U3O8; 0 to 25% clay; etc). To cope with the composition swings, sizing screens were selected to provide classification in the grinding circuit. The grinding circuit started up close to the design to provide minus 500 micron slurry. The 50% solids (wt) ground ore slurry proved to be difficult to transport to and process at the Key Lake Mill. Slurry containing high concentrations of high density pitchblende (about spgr 8.0) and low concentration of stabilizing clays, would settle in containers. Ore transport efficiency to Key Lake was found to be unacceptable.A test classification cyclone was installed in the grinding circuit at McArthur River early in 2002. The cyclone operating parameters were not typical, but the cyclone was made to work very successfully. Transportation efficiency to Key Lake increased due to more stable slurry. Preferentially ground (fine) pitchblende particles were easier to leach at Key Lake. The radiation exposure for operators and maintenance personnel to handle the more stable slurry was also reduced.The classification sizing screens were removed from the McArthur River grinding circuit and replaced by permanent classification cyclones late in 2002.INTRODUCTIONThe McArthur River mine and Key Lake mill operations are located in northern Saskatchewan, approximately 650 and 720 kilometres from Saskatoon, respectively. Figure 1 is a location map. McArthur River is the world's largest, high-grade uranium mine, with a production capacity of 18.7 million pounds U3O8 annually. (Rosner and Edwards 1998, Dyck 2000, Jamrozek 2000, Rodgers 2001) Proven and probable reserves are more than 473 million pounds U3O8. McArthur River ore, grading on average 21% U3O8, is milled at Cameco's Key Lake operation, 80 kilometres southwest by road. McArthur River production began in December 1999."

Jan 1, 2004

The usual metallurgical, engineering and administrative activities associated with the handling and smelting of ores, and the subsequent handling and treatment of the products of smelting, present also problems of hygiene that engage the earnest attention of executives in all well-managed concerns.Again, associated with the employment of any considerable number of men, there is always present the problem of accident prevention.INDUSTRIAL HYGIENE.In the earliest records of lead min.ing and smelting there are references to the injurious effects of lead oh the health of the employees, and, with the advancement of medical science, lead poisoning has been the subject of many works by various authorities in many countries.Moreover, in practically every civilised country, there are laws governing the conduct of the lead industry, and in most cases these laws stipulate that employees shall receive compensation for disability caused by lead poisoning.This provision gives the problem an economic aspect. Apart from the legal and the economic aspects, however, there is the humanitarian aspect, which implies that the...

Jan 1, 1937

By Paul J. Sabatini, Yazen A. Khasawneh

"A Demag CC1800 crawler crane was partially erected on crane mats adjacent to a seawall when settlements near a corner of the crane mat area were observed to be slightly larger than previously assessed. A ground improvement program including installation of dry soil cement mix (DSM) piers was implemented to improve soil bearing capacity. Due to near-surface obstructions, only 75 percent of the DSM piers were installed to the design depth. Because of the partial installation of the DSM piers, an evaluation of the crane pad stability and the effect of the crane loading on the stability of an adjacent 10-ft high concrete seawall, which was believed to have limited (if any) reserve capacity, was required. A two-dimensional finite element model was developed to evaluate the responses of the partially improved ground and the sea wall to the loads imposed by the crane. Geotechnical site investigation and laboratory testing programs were performed to better define the subsurface conditions near the area where settlements occurred and to provide the required mechanical parameters for the soil constitutive model. Analysis results indicate that total and differential settlements of the crane pad and the increase in load on the seawall were tolerable provided limited excavation and replacement of weak dredged soils outside the DSM area would be implemented.INTRODUCTION & BACKGROUNDA Demag CC1800 was erected on 8 ft × 16 ft crane lattice mats at about 12 ft from an existing seawall. Approximately 3.5 in. of subsidence was observed at one corner of the crane mats, while the crane was partially erected and stationary. The approximate location of the crane mats with respect to the existing seawall when the subsidence occurred is shown on Fig. 1.The seawall consists of a reinforced concrete wall connected by reinforced concrete bents to a composite section of sheet pile wall; the total depth of the seawall is about 29 ft. The bents are spaced at about 20’4” and supported by five piles at each bent location. The composite sheet pile consists of concrete and a sheet pile section with a reinforced concrete wale section. The retaining wall is about 10 ft in height and is supported at three levels. The first support level comprises a 2-½” diameter steel rod near the top of the wall spaced at 40’8” the second and third level supports comprise 1-½” diameter steel rods spaced at about 5’6”. The second level support is inclined at about 10 degrees below horizontal and the third level support is oriented horizontally through the wall footing. A schematic of the seawall section is shown on Fig. 2.A geotechnical site investigation was implemented soon after the subsidence was observed. The program included advancing four borings to a depth ranging from 16 ft below ground surface (bgs) to about 30 ft bgs. In general, the investigation showed sandy material (likely fill that was used behind the retaining wall) from the ground surface in two borings located immediately behind the retaining wall. The other two borings furthest from the retaining wall showed very soft to soft clay (possibly dredged material) from the ground surface to a depth of about 10 ft bgs. Based on this information, the ultimate bearing capacity of the subsoils was estimated to range from 1,200 to 2,000 pounds per square feet (psf). From the anticipated crane loading (weight of the crane and loading lifts), a minimum allowable bearing capacity of about 1,500 psf would be required for safe operation. To achieve the required bearing capacity a ground improvement program was selected and implemented."

Jan 1, 2017

By Prosser A. P

The conditions under which vanadium is rendered insoluble by silica in the alkali-roast process have been investigated starting with both slag and reagent-grade materials. The inert phase is a glass formed slowlyfrom soluble NaV03 produced at lower temperatures. It contains approximately 30 per cent V in a partly reduced state; iron is not a principal component. Some of the vanadium in the inert phase is slowly returned to a soluble form by heating in an oxidizing atmosphere below the temperature at which the glass is formed (750°C). As the reaction leading to the required, soluble form of vanadium is also slow between 600 and 750° optimization and control of the temperature profile and atmosphere in the furnace, and the residence time of the solids, are necessary to ensure high vanadium extraction during subsequent leaching.

Jan 1, 1976

By H. Zhu, Y. Sato, O. Takeda, K. Nakano

Recycling of rare earth magnet wastes is essential to insure the stable supply of rare earth resources. For the development of a novel recycling process, the removal of rare earth oxide from an off-spec alloy magnet was investigated by melting the alloy magnet at 1503 K together with fluoride flux, LiF-50 mol% NdF3 and LiF-?25 mol% NdF3-25 mol% DyF3. After melting, the separation of magnet alloy from the fluoride flux was achieved, and neither suspension of alloy in the flux nor suspension of flux in the alloy was observed. Oxygen concentration in the alloy decreased from 5000 mass-ppm to 160 mass-ppm by utilizing 1.5 times of equivalent amount of flux needed to completely dissolve the oxide. The investigated process is suitable for mildly contaminated waste such as a used (end-of-life) magnet because of its simplicity, low energy consumption and small limitation on location for operation.

Jan 1, 2014

Procedures employing thiocyanate and dithiol complexes of molybdenum have been developed for the determination of the metal in the presence of large quantities of ferric iron. The procedures are developed for field application and it is possible to complete 200 analyses per day with laboratory accuracy. Use is made of sulphuric acid extraction and ascorbic acid reduction in the case of the thiocyanate procedure whilst the reducing system in the dithiol procedure is potassium iodide-sodium sulphite. Using a simple photometer the range of determination possible is 0-10~g for the thiocyanate procedure and 0-5 g for dithioI.INTRODUCTIONOf the many colorimetric procedures that have been developed for the determination of molybdenum only those using the thiocyanate or toluene-3, 4-dithiol complexes of the metal are sufficiently free from interference to be of use in geochemical prospecting. Rapid methods based on both these complexes 'have been developed at the. Broken Hill Division of The University of New South Wales as part of a general programme designed to improve geochemical procedures. Whilst speed rather than high accuracy is the important factor in prospecting, the aim of the programme is to develop procedures which will allow determination of 200· samples per man-day without loss of normal laboratory accuracy for the methods concerned.In most geochemical procedures visual estimation of a coloured complex is used in the determination of the quantity of metal present. At the high rate of sample determination of the improved methods this procedure places severe strain on the eyes. For this reason all methods are designed for determination by means of a simple filter photometer...

Jan 1, 1965

The 53 countries that constituted Africa in 1992 accounted for a significant portion of total world output of a number of mineral commodities. However, the continent's total output for a number of major mineral commodities declined relative to the volume produced during 1991. (See tables 1 and 2.) The most conspicuous declines in mineral production from 1991 to 1992 were for cobalt and copper (declines of 28.6 % and 23.4 %, respectively), which could be partially attributed to mining and metal processing difficulties caused by political and economic disruptions in Zaire and for uranium (12 % drop), for which much of the continental production decline was ascribed to Namibian cutbacks in response to lower world prices. The severe regional drought also adversely affected the mineral industry in a number of sub-Saharan nations.

Jan 1, 1994

By Richard Phiri, Mike Milupi, Jackson Kapobe, Anton Lemmer, Charles Mazala

Sustainability of plant operations in a rapidly changing mining environment requires a well-trained workforce to ensure smooth running of operations. To ensure availability of trained labor, Mopani Copper Mines PLC set up a training facility in 2013. The school offers training in Engineering, Mining and Process. The engineering section enrolls grade 12 school leavers for artisan training. Mining section offers comprehensive safety induction program to employees and contractors to meet the Mopani zero tolerance accidents safety policy. The process training section offers advanced training programs for plant operating personnel and university graduates. The program includes needs analysis, theoretical metallurgical modules, practical plant training and e-learning modules. The school also offers assaying and sampling courses. All the above courses are extended to individuals and other mining houses outside Mopani wishing to have their personnel trained. The Mopani sustainable development academy ensures that contractors engaged on the Mopani sites are fully registered, comply with all relevant regulations and have undergone induction program before they can be allowed to work on the mine. INTRODUCTION “Sustainable operation of the mining industry requires a continuous supply of trained human resources” (Kapobe et al., 2018). The publication by the Asian Development Bank (2014) argued that there was a mismatch between the demand for high-level skills and the oversupply of low-level skills. Globally, the mining industry requires continued supply of skilled manpower for its complex operations and long term projects whose sustainability is absolutely necessary. Implementation of newer technologies in plant operations to ensure cost effective and efficient operations requires trained and skilled labor at various levels to handle ever-changing challenges. Dutz (2007:152–156) made three recommendations for Building Worker and Management Skills in India: Strengthen enterprise - based training. The government should help ensure that the benefits of in- service training are widely recognized by enterprises, while simultaneously providing strong financial incentives Improve vocational training - Vocational education and training systems have been unsuccessful in preparing graduates to meet market needs, particularly because of a lack of interaction with industry. Public and private vocational education and training providers should be strengthened to make them more responsive to industry demands. Curricula should be updated to reflect modern technologies. Strengthen business, management education, management of research and commercialization - business and management education should be strengthened through public-private partnerships. Innovative management courses should be introduced. Although these recommendations were made for India, they also apply to Zambia and other low and medium income nations.

Jan 1, 2019

By W. E. Falck, A. Usubiaga, J. Spangenberg, P. Schepelmann, S. Šolar, D. Wittmer, F. Blanchard

The extraction and processing of mineral resources may be accompanied by environmental impacts. In spite of technological advancements, the enormous increase in production volumes within the last decades has induced sizeable environmental impacts along the life-cycle of products. Beside environmental impacts, social issues associated with mining need to be considered to ensure the social acceptability of mining activities. The project EO-MINERS aims at deploying Earth Observation (EO) tools to inform best practices in mining and to thus assist the global mineral resources industries in their transition to sustainable development. In order to facilitate the handling of complex sets of information requirements from a wide variety of stakeholders, a set of indicators was developed that will inform the process of EO tool and services development. The project strives to enable stakeholders outside the industry to meaningfully participate in decision-finding processes on mining-related issues by developing and providing EO products and services that fit the information requirements. The project has identified a wide range of such information requirements by stakeholders that could be potentially provided by EO tools. The applicability of the EO tools on the local level is tested on three mining sites.

Jan 1, 2011

global mining boom and in-creased demand for iron ore has lead to a resurgence in the mining industry in Minnesota. At the combined 81st Annual Minnesota Section of SME Meeting and 69th Annual University of Minnesota Mining Symposium, April 15-16 in Duluth, MN, this resurgence was the hot topic as new mining projects were featured in the keynote session. The meeting attracted more than 400 mining industry professionals, including engineers, executives, mining managers and suppliers from around the world. This year?s theme was ?New Ventures in Mining.? The meeting included concurrent technical papers sessions, a keynote session that featured three distinguished speakers and a panel discussion that provided updates on new mining developments in the state. The Minnesota Section of SME technical papers were presented in concurrent sessions, one on mining and one on mineral processing. The mining session included papers on drilling, ore blending, slope stabilization, dust control and operations management. The mineral processing session included papers on plant-control technology, ball mills, pellet strength and fans. Also offered was an SME short course titled ?Simulation based pellet induration optimization.? The Minnesota Section of SME held its annual business meeting during the conference. The 69th Annual University of Minnesota Mining Symposium technical sessions were held on April 15 and also consisted of concurrent sessions on mining and mineral processing. Mining session topics included logistics management, real-time performance measurement, uses for taconite aggregate and environmental issues. The mineral processing session included papers on ore liberation characteristics, zeta potential studies, induration modeling, fuel optimization and conveyor belts. The combined conference included a tradeshow with more than 80 booth spaces featuring vendors offering products and services to Minnesota?s booming mining industry. More than 900 people, including conference registrants and special invited guests of the vendors, at-tended the tradeshow opening reception. This was the largest trade show in many years ? an indication of the vitality of the mining industry in Minnesota.

Jan 1, 2008

By A. E. Raddatz

The Bureau of Mines is investigating methods for recovering tungsten from domestic resources. A calcine-quench-leach (CQL) technique was developed for the extraction of tungsten from the Golconda, Nev., hot springs ores. The deposit contains disseminated tungsten that cannot be beneficiated by conventional techniques and must be treated by hydro-metallurgical methods. The CQL procedure consists of calcining the ore at 900° C for 3 hours, quenching in a solution containing 1.5 parts of Na2C03 and 1.5 parts of NaOH per part of WO3 in the ore and at a solution-to-ore ratio of 3 to 1, leaching at 200° C and at 250 psig for 3 hours, and filtering and washing the residue. A series of closed-circuit batch tests showed that 92 pct of the tungsten was extracted from a sample containing 2.32 wt-pct W03. The pregnant solution contained 11 g/l W03.

Jan 1, 1982

By Richard Burt

"In seeking to supply the ever increasing needs for raw materials, the mining industry has been required to develop lower grade resources in increasingly remote regions of the world. This has resulted in the extension of many frontiers, both technologically and geographically.The accent of mineral processing research over the last few decades has been to “do existing things better”. There have been many breakthroughs in equipment and processes; however in general the accent has been to increase capacity of existing unit processes, often by orders of magnitude, or to refine the process itself by basic research and development. This has lead to added sophistication, enabling the process engineer to maintain optimum performance of his equipment while reducing the cost, and the amount of labour needed to operate the plant.While much of the increased requirement for resources is handled by the development of ever larger, lower grade orebodies, a significant portion still comes from the small miner - even the artisanal miner - operating in remote and often politically sensitive parts of the world. For them, innovation and simplicity are the keys, not sophistication.The tension between sophistication and simplicity - or research and reality - is specially evident in the area of gravity concentration of rare metals, such as tin and tantalum. This paper looks at this tension, primarily from the eyes of an operator and seeks to put into perspective the two paradigms."

Jan 1, 1999