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By H. Tiefel, M. Schneider, T. Neesse, J. Regler, J. Dueck, F. Donhauser

In practice the advantages of high-quality hydrocyclone separation are often reduced due to varying feed suspension properties, solids concentrations and particle size distributions. Control systems of large hydrocyclones are usually fitted with controllable underflow nozzles, which is not practical for small hydrocyclone batteries. Therefore, a new control system for a battery of hydrocyclones with a nominal diameter of 150 mm was invented at the LUR in cooperation with AKW Apparate und Verfahren GmbH & Co. KG. This process was developed for bentonite slurry regeneration associated with tunnel excavation using bentonite slurry as a transport aid and lubricant.

Jan 1, 2003

By M. Schneider, J. Regler, Th. Neesse, AKW A. + V GmbH & Co., J. Dueck, F. Donhauser

"In practice the advantages of high-quality hydrocyclone separation are often reduced due to varying feed suspension properties, solids concentrations and particle size distributions. Therefore, a new control system for a battery of hydrocyclones with a nominal diameter of 150 mm was developed for bentonite slurry regeneration associated with tunnel excavation using bentonite slurry as a transport aid and lubricant.As can be seen from Fig. 1, the hydrocyclone battery has been modified for regulation purpose. The battery was manufactured with an overflow collector as a closed pressure chamber (1) with a discharge pipe (2) where the throttling valve (3) was installed.With increased stepwise throttling of the overflow, the volume split is changed with the effect that the solids discharge in the underflow is increased. To stabilize the total throughput, the feed pump speed is simultaneously increased so that the pressure drop ?p across the hydrocyclones (9) remains approximately constant. However, this causes the increasing pressure inside the hydrocyclones, which results in a further intensification of the underflow discharge. After the detection of the break through of the air core (transition state) by the capacitive sensor (4), the throttle valve is shortly opened, and a new regulation interval can start again. The control concept is focused on maintaining the optimum operating state, characterized by the underflow discharge shape at the transition state between rope and umbrella discharge."

Jan 1, 2003

Diamond drilling is a relatively new commodity in terms of drilling. The first known diamond drilling activities were carried out in the Swiss Alps around 1863 when the Swiss engineer M Leschot designed and made a tube with a diamond set face which was used in probing ahead drilling for the Mont Cenis tunnel (Figure 1). Craelius AB which today is a part of the Atlas Copco Group was formed in 1886. The name Craelius is a family name and the founder of the company was Per Anton Craelius (Figure 2). He went to the United States to study this new technology using diamonds to extract core samples and when he returned to Sweden designed his first diamond drilling machine. It was a man-powered drill needing a crew of six men, two to crank the unit, one to feed, two to power the flush pump and a foreman (Figure 3). As time passed through research and development, the original design was improved and manpower was substituted for steam engines and later combustion engines or electric motors (Figure 4). During the 1930s the drills radically changed designs and took the form of the short stroke drills which to a certain extent are still in use today. The original design of these drills have been refined during the years, hydraulic chucks, gear boxes and other improvements have been added.

Jan 1, 1995

By Pasi Latva-Pukkila

Underground rock drilling has gone through intense development during the last 25 years. Mechanization and hydraulics have greatly increased the efficiency of drilling and improved the environment of the drill operator. As the total economy has become more and more important, the development has resulted in greater overall economy in drilling. The latest evolution step is computerization of drilling equipment. Computerization has been applied to tunnelling jumbos, long- hole drilling rigs and bolting rigs. With today's technology computerization is the natural way to increase capacity and productivity of the drilling process. However, it is still impractical to implement total "robotic" drilling. In computerized drilling the operator's role continues to be vital in controlling the drilling process and in analyzing the effect of individual parameters on the whole excavation process. Today this is called "CAD" - Computer Aided Drilling.

Jan 1, 1989

By Russell A. Luke

"Modular Mining's computerized LHD position monitoring and dispatching system commenced operation at the De Beers Finsch Mine in mid- J99J. A sophisticated blend of proven and new technologies links the dispatcher at the workstation console on the surface with the LHD operators several hundred metres below. The dispatcher allocates each LHD to a priority tip and loading drive based on instructions provided by the miners and shift bosses underground. LHD operators receive tip and loading drive allocations on the vehicle computer console which communicates data via a Leaky Feeder radio network. The operators interact with the console to notify the dispatcher of delays, breakdowns, and changes in tip and tunnel status. The underground terminal displays allow shift bosses to monitor the progress of the LHDs as they pass infrared beacons (IRs) located in the tips loading drives and rim tunnel main haulage ways. The terminals also provide on-line statistics for the current and previous shifts. Future enhancements include optimized dispatching and interfacing to a PLC system controlling ventilation. Further, token ring-based loop UHF radios are being investigated as an alternative to the Leaky Feeder data radio network. IntroductionFinsch first contacted Modular about an LHD monitoring and dispatching system in late 1988. At that time, Modular declined a request for a formal quotation but agreed to perform an engineering feasibility study. The study was issued in mid-1989 and confirmed Finsch's belief that an underground system could be developed with technology available at that time. A contract for the system was signed the following year and, in May of 1991, the system began operation. By the end of 1991, LHDs on both production levels of the mine were under the control of the system."

Jan 1, 1993

By Kidd CH

The excavation of a coal mine or any other mine, tunnel, or quarry, below the water table establishes a void towards which ground- water will flow. Inflows into the mine, if significant, can cause not only problems such as flooding, and/or muddy floors, in the mine, but commonly also require disposal of poor quality groundwater. The flow of groundwater towards a mine is accompanied by a decline in groundwater levels, which may extend up to several kilo- metres around the mine. This may seriously effect vegetation, stream flow and existing users of groundwater. At the pit face groundwater gradients can also cause slope stability problems and where a water table is intersected, increase blasting costs.

Jan 1, 1983

By Elmer A. Peña M

Dado que la concentración de sulfuros de fierro: pirita y pirrotita aplicados gravimétricamente en espirales Humphreys obtuvo resultados óptimos tanto en lo económico como en lo metalúrgico, surge la necesidad de construir una planta concentradora de sulfuros de hierro en la Cerro de Pasco Corporation utilizando como cabeza los relaves de la planta de flotación de minerales de cobre. En este sentido, el objetivo del texto describe el proceso de dicha concentración, donde señala que la alimentación a la nueva planta es una pulpa que requiere mantenimiento de supervisión y mantenimiento, generando un concentrado de fierro a un costo de s/.6. 00 T. C. S. contra s/. 105. 00 T. C. S.; costo del concentrado de fierro producido por flotación en 1961. Asimismo, las diferencias de gravedad específica entre sulfuros de fierro y ganga cuarcífera han ido aprovechados para lograr un ejemplo donde la concentración gravimétrica, actúa con éxito frente al actualmente difundido proceso de concentración por flotación.

Aug 20, 1963

By W. L. Zeigler

During the middle 1880's, shortly after the discovery of silver-lead ores in the Coeur d'Alene district of northern Idaho, it became apparent that concentration of the ores would be necessary to obtain a profitable product. Too much siliceous material was present for direct smelting, and the majority of the ores found at depth were too low in metallic content for economic smelting processes at the time. As the ores occurred in quartzite shear zones with siderite and quartz gangue, a large quantity of waste material was present in all the mines. As the galena was not finely disseminated, this made possible relatively good extraction of the argentiferous galena by coarse concentration. The first concentrators consisted mainly of coarse crushing, screening and jigging, principally by Harz jigs, the slimes being treated on buddles. Later Wilfley tables took the place of sand jigs and vanners superseded the buddles. Because of the marketing conditions, no attempt was made until 1900 to effect a recovery on the zinc minerals present, which were found associated in varying amounts with the galena. All through this period, the greater part of the production was obtained from mines containing ore assaying high in lead and low in zinc. Parts of some ore bodies would be reversed in this respect, so that ores high in zinc were left intact. During the decade after 1910, several important mines, The Success and The Interstate Callahan, containing ores high in zinc, were put into operation and were a material aid in the needed zinc production during World War I. Gravity concentration by jigs and tables was used during this period, with bulk flotation increasing in popularity for the treatment of the fine material that had already been treated by ordinary slime concentrating machinery. No extra fine grinding for flotation concentration was thought profitable at the time. Tailings Discharged into Streams From the start of mining and milling operations in this district until 1904, no attempt was made by the various mills in the upper district to impound or stack their tailings. They discharged them directly into the adjacent creeks or streams, to be carried away by high water. The Bunker Hill and Sullivan and the Last Chance mines, both in the relatively flat valley of the district, stacked huge piles of the coarse jig tailings on the near-by river bottom. Rain and snowfall are heavy in the Coeur d'Alene district, as it is on the heavily timbered Pacific slope of the Bitter Root Mountains. A heavy runoff occurs every spring and there is an occasional flood of disastrous proportions when warm "Chinook" winds accompanied by rain

Jan 1, 1949

By F. W. McQuiston

Idarado Mining Company's mill and surface plant are at the portal of the Treasury tunnel at elevation 10,625 ft, 12 miles south of Ouray, Colo. In 1943 and 1944 this tunnel was extended in a westerly direction to tap the Black Bear vein, and, together with the recently completed 1100-ft inclined Treasury raise, provides access to the Black Bear mine. In 1945 a 250-ton mill was placed in operation to process development ores containing much needed copper, lead and zinc for war requirements, and to serve as a pilot testing unit for larger scale milling operations. In the years 1902 to 1927 some 329,000 tons of ore were produced from mine workings on the Black Bear vein that extended downward from elevation I2,325 ft at the Black Bear tunnel portal to elevation 11,618 ft, the lowest level of the mine. The ores were taken to the Cascade and Smuggler-Union mills near Telluride over two aerial tramways. Gold bullion, a copper-lead concentrate, and a zinc concentrate were produced. Ores The Black Bear is a compound fissure vein that has undergone several stages of mineralization. The first important stage is represented by complex ores of copper. lead and zinc in a quartz gangue. Precious metal content in this stage is low. The galenn is argentiferous and varying amounts of tetrahedrite, freibergite and bornite tend to increase the normal copper content represented in chalcopyrite. The zinc occurs as a true sphalerite with little or no iron. Later re-openings of the fissure took place more or less co-extensively with the successive introduction of (I) abundant quartz gangue containing minor amounts of chalcopyrite, galena and sphalerite; (2) free gold in a fluoritic quartz gangue; and (3) barren, low-grade quartz with minor amounts of pyrite as the only important sulphide. The sulphides show practically no oxidation and little mineralogic inter-growth. Because of the common overlapping of these successive stages of mineralization within a given mining area, considerable dilution of the base-metal content takes place, thus lowering the average mill-head grade. Plant Practice Metallurgical testing was started shortly after the Black Bear vein was encountered on Treasury tunnel level in 1944. Laboratory tests showed good flotability of the minerals in the ore and indicated an economic separation could be made of the copper, lead and zinc minerals into their respective concentrates. The success of the separation is close reagent control to maintain a balance between promotion and depression of the sulphides. To maintain this balance reagent consumption for the three metal separation is considerably higher than in ordinary lead-zinc flotation.

Jan 1, 1949

By R. Kuyvenhoven, A. Parbhakar-Fox, X. Prieto, J. Quevedo, L. V. Danyushevsky

This paper presents the results of a study focussed on determining the distribution of cobalt in different types of pyrite of the La Estrella IOCG deposit in Chile. In the IOCG mineral deposits, where copper is the main product, the quantification and distribution of cobalt is required to correctly define the technical and economic viability of recovering cobalt as a by-product. In the La Estrella mineral deposit, seven alteration and mineralisation events were recognised through both optical and automated electronic mineralogical analysis. Of these seven events, five different types of pyrites were identified, each with unique characteristics of the pyrite crystals. Through advanced elemental analysis of these five types of pyrites, it was determined that the concentration and distribution of cobalt within the pyrite crystal is dependent on the mineralisation event. The results indicate high cobalt concentrations in the early pyrite mineralisation events, associated with relatively fine pyrite grains, and cobalt generally occurring in a solid form in the pyrite core. The late pyrite mineralisation event exhibits the lowest concentrations of cobalt, with cobalt predominantly present along the outer periphery of the pyrite. These results are relevant from a metallurgical point of view because the preferential location of cobalt within the pyrite crystal will influence the maximum metallurgical recovery of cobalt. For this, a cobaltiferous pyrite concentrate must be formed which, according to the characteristics of pyrite, must be processed with the optimal solubilisation method. The overall objective is to ensure both good cobalt recovery and a high concentration of cobalt in the leach solution resulting from pyrite leaching. Keywords: Cobalt, pyrite, IOCG, copper, metallurgical recovery, solubilisation, Chile

Jan 1, 2020

By J Q. Cooper

The New Zealand rail authority, Kiwi Rail and Auckland Regional Transport Authority (ARTA), are jointly planning a new mainline rail link between Auckland’s downtown Britomart Station and the existing Western Line at Mt Eden. In 2009, APB&B, a consortia of Aecom, Beca, Parsons Brinkerhoff and Hassell Architects where commissioned to develop the conceptual design, Assessment of Environmental Effects (AEE) and business case for the new 3 km rail line towards preparing a Notice of Requirement to protect the route through Auckland’s central business district.This paper describes the engineering challenges in the development of the conceptual design for the three proposed underground stations, the running tunnels and connections to the existing network. Feasible alignment and station location options were developed and evaluated using multi-criteria analysis based on key client functional requirements, constraint mapping and environmental impacts. The resulting preferred scheme was then developed to a conceptual design suffi cient for assessment of environmental effects, risks, and the development of a robust construction methodology to allow high level capital cost estimates.The paper describes some of the major challenges overcome to develop the concept, including steep gradients, narrow street envelopes with existing buildings and structures, the need for large platform spaces with low ECBF rock cover and complex connections at Britomart and the main line near Mt Eden.The development of the conceptual design of the underground stations in particular demonstrates the need for a holistic value engineering approach to satisfying the architectural and functional requirements, in a highly constrained dense urban environment and at lowest practical cost. The construction methodology was a key input to the conceptual design development throughout.The conceptual design will be used as the fundamental basis for the development of the AEE and business case for the project in the future.

Mar 8, 2011

By Ali Ahmadi, Andreas Rausch, Angela Binder, Stefan von der Mark, Dhananjeyan Jeyaraj, Jana Thomas, Nils Nöther, Stefan Wittek, Thomas Ulrich, Eleni Gerolymatou, Mario Kolling, Helmut Mischo, Michael D. Martin, Tugba Sen, Jens-André Paffenholz, Erik Farys, Oliver Langefeld, Wilfried Ließmann

This paper outlines the MOVIE project, which is dedicated to the development of a digital twin for an underground laboratory at the research and education mine “Forschungs- und Lehrbergwerk Reiche Zeche” in Freiberg (Germany). Data from induced rock deformations and temperature fluctuations is collected using fiber-optic sensors. The objective of the project is to establish a virtual laboratory for real-time analysis of the interactions between geology, geomechanics, geometry and ventilation. This will be achieved by integrating models from these disciplines with artificial intelligence, creating a sophisticated hybrid model. The insights gained will enhance safety and efficiency in mining through improved digital planning options, ultimately contributing to more effective resource management and operational decision-making in different mining environments.

Feb 1, 2025

By Denis Labrie

Résumé Cent soixante (160) câbles d'ancrage ont été installés au toit de la rampe à la Mine-laboratoire de CANMET à Val-d'Or, Qué bec, Canada, pour prévenir toute dégradation suite à l'élargissement de la voie de roulage dans un secteur tournant à 180 degrés, communément appelé Virage Santa Barbara. Le roc à cet endroit est de nature bloqueuse et stratifiée, et son épaisseur au toit de la rampe est limitée à environ dix (10) mètres, le tout sous une couche de terrain meuble saturée en permanence. Le soutènement mis en place a été conçu pour former une zone de compression et supporter une strate de roc d?environ quatre (4) mètres d'épaisseur. Les critères de conception et les méthodes d'installation sont présentées. Un contrôle de qualité rigoureux a été effectué au moment de la mise en place du support, notamment en ce qui concerne la mise en tension des câbles eux-mêmes et la qualité du béton utilisé lors de l'injection. Des instruments de mesure seront mis en place sous peu pour dépister tout mouvement éventuel au toit de la rampe. Abstract Design and installation of an active mine ground support using tensioned cables at the Experimental Mine, Val-d?Or, Québec, Canada. One hundred sixty (160) cables were installed at the back of the ramp at the CANMET?s Experimental Mine located in Val-d?Or, Québec, Canada, to prevent any degradation of the ground after the enlargement of the roadway in a sector turning at 180 degrees, usually called Virage Santa Barbara. The nature of the rock mass in this area is blocky and stratified, and its thickness above the ramp does not exceed ten (10) metres. Eight (8) metres of soil, mostly saturated, cover the bedrock on top of the ramp. The ground support was designed to form a compression zone at the back, aimed to carry a strata of rock of around four (4) metres thick. The design criteria and the methods of installation of the ground support are described in the paper. A strict control of the quality of the grout used for injection and the tension placed in the cables was carried out during the installation of the support. Ground monitors will be installed soon, to detect any movement that could take place above the ramp.

May 1, 2001

Geosynclines have been well studied for many years, but very little has been written about the concepts of sedimentary basins in spite of the vast amount of data available. They have been regarded, perhaps, as well- understood intuitively, and therefore not worthy of study. Many of the fundamental concepts of geology were developed during the 19th Century with the construction of coal mines, canals and railways. It was a happy chance that led railway engineers in the early days to think that trains could not climb any but the smallest gradient, so, in Britain at -least, numerous railway cuttings and tunnels were made. These exposed to view and study, in a better form than Nature usually provides, a great deal of interesting geology. Because of the lack of literature about the concepts of sedimentary basins, it is not possible to be sure what the early geologists thought. It seems that sedimentary basins were regarded as recording a history of subsidence during the early stages, when a transgressive sequence accumulated; and a history of uplift during the later stages, when a regressive sequence accumulated. It seemed axiomatic that the age of folding and faulting was younger than the rocks folded or Faulted.

Jan 1, 1987

By Roberto J. Guardia, Robert A. Robinson, John Wilkerson, Wick Haxton

Several candidate sites have been proposed for the Deep Underground Science and Engineering Laboratory (DUSEL), a facility that would provide over 2000 meters of overburden to screen out cosmic rays that would otherwise interfere with experiments. Types of anticipated experiments include: detection of dark matter and stellar neutrinos, and evaluation of deep microbial life forms. Engineering experiments might include more refined scanning devices to “see” rock defects ahead of tunneling, improved predictive models for groundwater inflows and tunnel support requirements, and improved instrumentation for monitoring in-situ stresses, rock deformations, and pore water pressures. Spin-offs from this research might include more sensitive security detectors for scrutinizing shipping containers, new drugs based on new microbes, and improved sensor systems for tunneling. A site near Leavenworth, WA, was assessed and shown to have numerous topographic and geotechnical advantages. Rock cover is on the order of 2250 meters. The granitic bedrock is suitable for tunneling a variety of large underground openings.

Jan 1, 2005

By Jon Y. Kaneshiro, Donald W. Scapuzzi

The primary purpose of the Prototype Installation Facility (PIF) for the Superconducting Super Collider (SSC) in this conceptual design was to test the magnets and other physics equipment. PIF was located in the northwest quadrant of the SSC 54 mile (87 km) main ring and consists of the first segment of tunnels, approximately 17,060 lineal feet (5.2 km) of 12 foot inner-diameter (ID) (3.7 m) tunnel, three 250 ± foot (60 m) deep shafts, connecting tunnels, and associated niches and alcoves. PIF would be the first portion of the main ring collider tunnel to be constructed. The geology, underground excavation conditions, underground facilities, and contractual considerations are discussed.

Jan 1, 1991

By Neale R. Neelameggham

"Most chemical process plants and metallurgical production facilities have some sort of cogeneration to minimize process energy costs. Use of Alternative Energy Production from sun and wind power with storage can become an integral part of a process plant utility. This will facilitate reduced fossil fuel usage and help minimize thermal emissions. This will be similar to Pollution Control equipment, which have become an essential part of process plants in the past four decades. Conceptual flow sheets of such Process Utility schemes are presented.IntroductionPower is supplied to industries, commercial and residential users. Over the past decade, Electric Utility companies have made major inroads, in introducing alternative energy resources in an attempt to somewhat reduce fossil fuel use in power generation. Now, on a much larger scale than in the early 1980s, residential users, motivated by government provided tax credits, have started installing alternative energy generators such as roof top wind mills or roof-top photovoltaic generators. This will minimize future energy costs, help control thermal emissions etc. This alternative power generation is typically connected to the existing power grid with two way power metering. However, the use of alternative energy generation has not been seen at large industrial sites yet.Paul Scherer Institute, Switzerland and the NREL laboratories in Colorado, are two of the several institutes which have been developing how solar thermal power can be used to supply the endothermic input energy in chemical and metallurgical processes. The theme of this present symposium addresses the above as well as the energy storage needs for such events to become continuous. This paper emphasizes the concept of how alternate energy can be used in the production of materials on a generic sense wherever there is a need for input energy – beyond endothermic process energy - while addressing how to reduce the thermal and carbon emissions.The alternative energy generation using wind or solar source is discontinuous due to the nature of the energy source. They are not only discontinuous but also variable. This necessitates storage of generated power for close to continuous use with variable loads. C Smith, et al pointed out in 2006, that 'the electric power industry has taken notice of the expansion of wind and its potential' in a summary article on integrating wind generation into utility systems.1 In 2009, the 1000 MW wind generation project in Texas had to be postponed to 2013 for lack of transmission.2 There are only a few large MW solar generation units in the US; the projects being slow mainly from lack of adequate storage and redistribution."

Jan 1, 2010

By M. Rizwan

Mine workings are progressing to greater depths as shallow mineral resources are being depleted, and civil engineering projects are nowadays being developed at substantial depths. The threat to tunnel stability posed by rockburst events has increased as a result of these high stress environments. Rockbursts are violent events capable of mobilizing large volumes of rock. In addition to the threat to safety and equipment, rockburst damage can significantly impact on operations, and cause loss of mining production, often the largest cost component of such events. Rehabilitation of such damage requires significant effort and resources. Tunnel walls and roof are usually well supported, but the installation of rock support in the floor is uncommon, particularly in mining environments. In the absence of rock support, floors of the excavations are vulnerable to rockburst damage. New concepts for containing damage of excavation floors by dissipation of the large transient forces using simple techniques or preselected and designed elements of sacrificial floor systems are presented. Two approaches to calculate the demand are presented: estimating load demand by assuming displacement levels and a response modification factor; and using a limit displacement approach to calculate elastic stiffness of the selected elements of the sacrificial support system. The proposed conceptual support systems have the capability of dissipating rockburst energy while retaining sufficient serviceability. It is considered that the concepts presented, for discussion, in this paper are logical and developable into practicable and economic solutions for tunnel floor support in rockbursting environments.

Jan 1, 2015

By Warren G. Burres

or more than 50 years the Portland Cement Association has represented the United States cement industry in matters relating to the technology and use of cement and concrete. Interestingly enough, PCA?s emphasis has been on concrete and its uses rather than on Portland cement. The cement industry realized long ago that cement is basic and serves its fundamental purpose as an ingredient in concrete. Cement could never be successful if concrete were not. Work with the users and specifiers of concrete had to be done at its end point of application--in a building, bridge, dam, highway or home. PCA, over its half century of existence, has been dedicated to this job. I should like to talk to you today on the less technical side of concrete--what it has been--what it is today--and what it can offer in future construction. Concrete, in many forms, has a long background extending from such notable historic times as the Roman Empire. Here, concrete made from pozzolanic cement from the slopes of Mt. Vesuvius was used to construct the Coliseum, home of the Roman circus; for the Appian Way, the ancient forerunner of the Interstate system; and the miles of aqueducts throughout Europe, many of which still carry water. In 1811 Joseph Asppin, an English bricklayer, made the first modern cement by the artificial mixing of pulverized limestone and clay materials. Ht,

Jan 1, 1971

By P. J. Routledge

THE purpose of this paper is to discuss the practical aspects of locating gravel deposits and of establishing efficient, portable concrete aggregate beneficiation plants for use on construction projects where limited amounts of high-quality gravel and sand are required. Certain projects are listed, in order to demonstrate the wide variety of problems encountered. Routledge Gravel Contractors Limited, North Vancouver, have supplied concrete aggregate for construction projects in British Colum-bia since 1957. In tl1at year, in sup-plying aggregate for a small project at a site on the northern coast of British Columbia, our quote was as follows: Concrete aggregate to specifications, f.o.b. scow, North Vancouver$ 1.75 per cu. yd. Scowing charges to site. $16.00 per cu. yd. At that time, our company realized that more attractive quotations could be submitted if local gravel was utilized where available. Port-able equipment was then acquired and a simple screening plant (Figures 1 and 1a) was at first used. This was later replaced by heavier, more versatile equipment. The use of suitable equipment, the keeping of cartage to a mini-

Jan 1, 1962