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By I. A. Cameron, F. Ham, R. Sriram

"Planned increases in electric furnace productivity and higher matte temperatures needed for the Sudbury Smelter's S02 Abatement Plan, require an improved matte tap hole. Since startup in 1978, the matte tap holes have been incrementally improved by the addition of copper cooling blocks around the refractory tap blocks. These improvements provided a tap block life of about 100 taps per campaign.In July 1993, a prototype matte taphole was installed in Number 2 Electric Furnace to develop the technology to increase tap hole service life. The design was based on a heat transfer model of the tapping process to determine candidate refractory materials and cooler arrangements. The prototype tap hole features increased copper cooling, high conductivity refractories and extensive instrumentation. Eight trial campaigns are reviewed outlining the performance of silicon carbide and graphite refractories and typical heat loads during tapping.IntroductionFalconbridge Limited operates two 36 MYA, 6 electrode submerged arc electric furnaces in Falconbridge, Ontario. The furnaces, commissioned in 1978, smelt a partially roasted nickel-copper calcine, to produce matte for converting and slag for discard. Additional details of the smelter are available in the literature(1-4).Each furnace was equipped with two matte tap holes located in the furnace end wall. Early in the campaign, matte tap holes were identified as a weak area in the furnace which could be improved. From 1981 to 1987, incremental improvements were made to the design by the addition of water cooled copper blocks. In 1993, a prototype matte tap hole was designed and installed in Number 2 electric furnace to develop the technology to increase tap hole service life. Improved service life is required to meet planned increases in electric fWl1ace productivity and the higher matte temperature needed for the smelter's S02 Abatement Plan.This paper reviews matte tap hole development since 1978; outlines the prototype matte tap hole design, refractory selection and installation; and details the performance of the prototype tap hole during the first eight campaigns."

Jan 1, 1995

By P. A. Verhey

"This paper describes a series of wear-resistant ceramic materials which have been successfully used in the mineral processing industry in Canada. Applications include use with metallic ores, coal, potash and asbestos, and in other processes where wear degradation is of major concern. The paper will also deal with considerations involving the selection of the different ceramic materials available. It will cover the installation of ceramic materials on support structures under varying process ' conditions, as well as the other physical and chemical factors which have to be taken into account.IntroductionIn the mineral processing industry, large volumes of ores tailings and other materials are handled. The abrasive nature of most of these materials results in extensive wear to both handling and processing equipment.Wear ratios versus cost, production losses due to down time and wear-resistant material suitability for a given application all demand particular attention when viewed against the need for increased efficiencies in existing processes. As a consequence, a very active continuous search for materials with improved wear resistance has been carried out for many years.In this search, starting about 20 years ago, dense ceramic materials were tested and evaluated in certain applications, notably in the iron ore and asbestos operations in Eastern Canada. As a result of substantially better performance both in continuous extended life and ultimate economics realized , wear-resistant ceramic applications developed progressively in many other processing applications, replacing traditionally used materials.In the vast majority of wear-resistant ceramic applications, considerable extended life over previously used materials was established. This invariably was not just a fractional increase but, in most cases , in factors of double, triple and often all the way up to 18 and 20 times the life of alternative materials used previously. In certain applications, extended life could not be measured and appears to be indefinite.Obviously, as a result of such experiences, the progressively wider use of wear-resistant ceramic materials is now an established trend."

Jan 1, 1981

By Scott L. Ewart, William M. Bryden, Donald E. Wakefield

"Osler, Hoskin & Harcourt develops commentaries from time to time on topics of legal interest. These may deal with new legislation, changes or developments in government policy or recent judicial decisions of importance to its clients. The commentaries are, of necessity, general in nature. Because the law which they deal with is often new and untested, it is hard to arrive at precise statements of the way in which the principle s discussed in a commentary might be applied in specific circumstances. When further guidance is needed , consult a solicitor.The purpose of the Bill is to simplify, modernize and standardize the regulation of mineral exploration and development in Ontario. Many of the changes proposed by the Bill are of an administrative nature and move much of the detail with respect to staking, assessment work, prospecting work, surveys, quarry permits and leases contained in the existing Mining Act to the Regulations contemplated under the Bill.The Bill will undergo revision and be re-introduced and therefore it is not the intention of this present article to detail the specific changes contemplated by the Bill; however , its more significant changes are as follows:1. Provision is made for a lifetime prospector's licence with the elimination of annual renewals;2. Perimeter staking of a block o f claims is permitted to reduce the cost of staking;3. Assessment work requirements are expressed in term s of dollars spent rather than days worked;4. Persons doing exploratory work are required to furnish notice to owners of surface rights of intention to perform assessment work;5. Annual work summaries will be available to the industry to lessen duplication in exploration work;6. The option of continuing assessment work rather than applying for a lease is provided;"

Jan 1, 1984

By Jorge Lema Patino

"The purpose of this paper is to determine the best techno-economic alternative for the treatment of tin ores, when comparing the various mining and metallurgical methods of preconcentration, concentration, volatilization (fuming) and up to the final stage of selling to the smelter. The study of the influence of the different parameters of cost, recovery and quoted prices has motivated the paper, which aims at determining the best process of ore treatment in terms of its techno-economic feasibility.Method of WorkOn the basis of head grades of 0.5, 0.75 and 1.0% tin, the following alternative methods of treatment are possible:1. Mining-Concentration-Smelting.2. Mining-Preconcentration-Fuming-Smelting.3. Mining-Concentration-Separation, with direct smelting and fuming/smelting of the two fractions produced.The calculations were carried out on the basis of existing information and publications concerning the various experimental recoveries in the operating mills of COMIBOL. In the case of concentrates containing less than 10% or more than 40% tin, extrapolation was required.The final grade of the tin concentrates and the gross weight of the concentrate were calculated on the basis of the estimated recovery curves. The costs of the preconcentration and the concentration stage s were determined per gross metric ton of material treated.The calculation of the cost of the smelting stage is similar for all the alternatives, the royalties and smelting charge varying with the grade of the final concentrate. In the fuming stage, a uniform recovery of 90% was taken in all cases so as to obtain a final concentrate grade of 65% tin, regardless of the head grade of the feed material.For the separation stage, the following considerations apply:a) Separation can be carried out by gravity separation or flotation methods.b) The cost of separation varies depending on the system used.c) The distribution of tin in the two fractions is 100% at this stage. In other words, there is no loss of tin during separation."

Jan 1, 1982

By Éric Côté

Introduction The 425 Main Ore Zone ? Block of ore partially mined in the late sixties; ? Area was sealed off for over 30 years due to SO2 emissions from oxidizing fill material; 425 Project goal ? Bring the zone back into production without jeopardizing the mine; ? Minimize risks associated to SO2;

Feb 1, 2008

By J. G. Whellock, R. J. Phillips, J. W. Matousek, P. J. Marcantonio

"Stillwater Mining Company (SMC), a partnership of Chevron Resources and Manville Corporation, produces a copper-nickel, platinum-palladium flotation concentrate at its Nye, Montana mine. The concentrate is then toll processed in Europe. Recognizing the economic advantage of treating the concentrates at the mine site and of retaining this strategic resource in the United States, the Company commissioned Tolltreck International Limited and International Process Research Corporation to conduct pilot scale smelting tests with a flowsheet that would maximize metal recoveries while satisfying the environmental requirements of operations at Stillwater.Primary smelting was conducted in a single phase, 50 k W, submerged-arc, electric furnace. Refining the product mattes to copper-nickel ""white-metal""; containing approximately 2% iron, was accomplished in a Tolltreck, IV-litre, top blown rotary converter. Over-all platinum and palladium recoveries were approximately 99%; copper and nickel recoveries averaged 94%. INTRODUCTION(l-4)Stillwater Mining Company (SMC) a partnership of Chevron Resources and Manville, operates a copper-nickel, platinum palladium mine and concentrator at Nye, Montana, located in the valley of the Stillwater River, approximately, 100 km southwest of Billings. It is North America's only primary producer of these precious metals. The Stillwater area was mined for chrome ore during World War U and the Korean War, but it was not until 1961 that attention was drawn to the similarities between the Stillwater Complex and the Bushveld Complex of South Africa with its deposits of platinum group metals.A concentrated search for platinum was begun by Manville Corporation in 1967. Its presence, together with palladium, in mineable quantities was confirmed in the period 1976-1978, and the first partnership to develop the deposits was formed by Manville and Chevron in 1979. Anaconda joined the group in 1983, and in 1985 its share was purchased by Lac Minerals. In 1988 the interests of Lac Minerals were purchased by Chevron and Manville.The decision to develop the mine and build a concentrator was made in 1986. Construction began in the fall of that year, and the first concentrate was produced six months later, in March 1987. Underground mining is done in a two-shift, five day- week operation. Since startup, the concentrator has operated on a 24 hour/day, 7 day/week schedule, treating an average of 635 tonnes of ore per day and producing approximately 10 tonnes of concentrate."

Jan 1, 1989

By S. N. Bhatnagar, S. K. Haldar

"Mineral exploration is an expensive speculative venture and calls for optimization of sampling. Exploration is generally planned in grid pattern to be conducted in phased manner. The objective of any such campaign is to assess the quality, quantity and its reliability. The traditional estimation methods are unable to provide a means of calculating the degree of reliability. Application of mathematical models can quantify the precision of estimation and bring forth decision-making criteria at any stage.In this paper three statistical and geostatistical models, viz., Frequency, Probability, and Semi-variogram, have been employed to evaluate sequential exploration data of RampuraAgucha zinc-lead deposit. The optimization in exploration for a specific objective has been highlighted.IntroductionAny exploration campaign demands heavy resource investment starting from the collection of the first sample to the production of the first ton of ore. The best estimation would be if the entire orebody is taken out and sampled. However, this is neither possible, nor desirable. Drilling is the primary tool of geological sampling. It shares the major portion of the investment and, thereby, warrants critical analysis at every stage during the ongoing exploration projects.The exploration program should be conducted as a well planned scheme based on a sequential evaluation approach in a phased way to achieve a specific objective. It would then be possible to evaluate exploration data at the completion of each phase by employing computer-based mathematical techniques to quantify the precision of the estimate for fulfillment of objectives. The subsequent drilling program should be modified accordingly."

Jan 1, 1987

By Jean-Luc Beaudoin

"In addition to the actual energy consumed, billing is dependent on the peak load and the power factor. The lower the power factor goes, the higher will be the penalty the consumer pays. The principles of a power factor regulator, the two ways of improving the power factor and methods for calculating the capacitor values required will be described.The rate structure of the utility company is founded on three cornerstones: the energy consumed during a given period of time and two penalties imposed when the power factor is low or the power demand is high. Even though the normal consumption of a customer might be 10 kW, with a peak demand of 20 kW only once a month, the wiring and associated equipment at the input to the customer's plant will have to accommodate this peak demand. The power company has no means of forecasting these demands and cannot therefore provide the additional equipment necessary. So it exacts a penalty, and the customer must take all possible steps to avoid these peak power demands. This can be accomplished by using an automatic peak load regulator which will selectively disconnect the loads which are not essential in the operation of a plant .The principles of such a controller will be described.Principles of power factor regulatorsThe operating principles of a power factor regulator will now be described. It might be asked why the power factor of an electrical installation in a mine, or a factory, should be corrected at all, but there is a simple answer. In addition to the actual energy consumed, the billing is dependent on the peak load and the power factor. The lower the power factor goes, the higher will be the penalty the consumer pays."

Jan 1, 1982

By Donald C. Craighead

"Overland conveyor systems to transport bulk materials from mines to processing plants or load-out stations have to be seriously considered as the viable alternative to truck and train haulage systems. With the ever-increasing price of diesel fuel, conveyors with their electrical drives generally prove to be the least costly when operating and maintenance expenses are analyzed for the life of the installation.IntroductionOverland conveyor systems are now considered as one of the viable alternatives which should be closely investigated when a mining company and its engineers initiate studies on methods of transporting raw materials from a mine to a processing plant or rail load-out station.This paper will generalize the overland conveyor and compare it with alternative handling systems. Each installation must be carefully studied to determine the best route, type of foundations river crossings; amount of excavation work for cut and fill, maintenance roads, etc. No two locations are the same nor are the principles of operation of an overland conveyor the same as those of a normal plant or mine belt conveyor. The proper time and effort must be put into the study of the system to evaluate the costs for comparison with other systems.The length of the overland conveyor depends on the layout of the mine and plant and the topography of the terrain between the terminals. Individual lengths may be up to 20 km, and a series of conveyors may extend 100 km or more.Advantages of Overland ConveyorsThe main advantage of overland conveyors is the low operating and maintenance costs which will be realized over its years of operation. Although truck haulage probably will permit lower capital investment during the initial phases of the mine development when the annual capacities have not developed to the design level, their operating and maintenance costs will be considerably higher. When evaluating the total costs per ton of material to be handled during the expected life of the operation and the projected increases for diesel fuel versus electricity, overland conveyor systems will generally prove to be economically more viable."

Jan 1, 1982

By Alfredo Bambaren

First Encounters between Communities and Mining 1. Importance, meaning and process 2. Antamina?s study case 3. ?Self-organization? theory (NLP) 4. The story we tell, the values we live 1. Importance, Meaning and Process ? First encounter stays in mind as a model. ? First encounter means foundation. ? First encounter builds the story.

May 1, 2010

By J. E. Tupper

"This paper will discuss strategies for the introduction of computer technology in the mine environment. More specifically, it will focus on issues such as: (a) make or buy; (b) programmer less mines; and (c) support from corporate groups.The paper relates these strategies to systems for mine operations. These will be illustrated by considering the implementation of some phases of these systems at Teck Corporation.IntroductionThis presentation addresses some of the major considerations in a strategy for mine computerization and then relates these considerations to the computerization cycle and Teck Corporation.Strategy is defined as a conceptual framework or plan to accomplish a goal. For purposes of this paper, the goals can be more simply defined for operational purposes as either increasing revenue or decreasing costs.The strategy will allow us the framework for measuring tactical decisions such as computer and software acquisitions.The Mine Life CycleTo start with, let us look at the mine life cycle from a computer systems point of view:-Exploration-Property Development-Feasibility-Construction-OperationFrom a systems point of view, the exploration cycle is oriented to geophysical and geochemical computing. Property development starts with drilling and building the geological data base. The feasibility cycle includes all stages of evaluating the decision to proceed with mine development: ore reserve calculations; mine planning; and financial projections. Construction includes project management and project accounting systems. Systems required for operation are those needed by personnel at the mine site."

Jan 1, 1982

By A. Sargeant

This paper evaluates the application of post consumer glass as a cementing agent in underground mine backfills. The underlying theory indicates that glass is pozzolanic and, when used in a finely divided form, behaves as an activator to generate binding products, thus contributing to the development of backfill strength. The objective of this study was to evaluate the strength performance of backfills when Normal Portland Cement is replaced with various percentages of post consumer glass. The study evaluated the performance of backfills prepared using tailings from three mines. Each backfill was prepared using unique recipes, and were evaluated at cure times of 7, 14, 28, 56, 112 and 224 days. Laboratory work involved visual, physical and chemical material characterization followed by strength evaluations. Results of strength assessment revealed that backfill prepared with glass is reactive and can contribute to the strength of backfill. The results also indicated that the reactivity of glass may be affected by the incorporation of slag within the recipe, the availability of lime and the level of hydration of the binders. The study concluded that, at 15 % glass replacement of NPC, backfill prepared with mine tailings, NPC and glass can achieve improved or equivalent strength performance compared to backfill prepared tailings and NPC alone.

May 1, 2007

By R. Phillips, A. G. Doll, D. J. Barratt

"The Bond low energy impact (crushing) work index test is specified to be performed on rock specimens between 50 mm and 75 mm in effective diameter. NQ-diameter drill core, frequently used in mineral exploration programs does not meet that specification, it being 45 mm diameter or less.This paper reports the effect of performing the impact test on contiguous sections of HQ diameter and NQ diameter core, exploring the hypothesis that the contiguous intervals give equivalent results in spite of the core diameter difference."

Jan 1, 2012

By Bo-Hyun Kim

Outline ? Strainburst criteria and hypotheses adapted for this study. ? Influence of excavation method on rock mass properties. ? Excavation disturbance factors vs. deformation modulus, etc. ? Estimation of blasting damage zone around excavation. ? Considerations of energy on burst-prone ground. ? Literature review & closed form solution. ? Numerical simulations. ? Summary and future works.

Oct 1, 2010

By A. Bauer

The correct application of large crater blasts in unfrozen tar sand is an effective means of resisting frost penetration during winter. This results in much higher productivity and considerably less down time with excavators during winter operations. The resulting flatter angle of repose of the highwall has readily been accommodated with slight modification to bucket-wheel excavator operating procedure. Other mining schemes call for large draglines to be located on top of the highwall, which can be as high as J80 feet. The question now arises as to the effect that blasting might have on the stability of such a situation in which the highwall includes potential planes of weakness. This paper applies blast vibration data from large-scale blasting in tar sand to the stability analysis for typical production situations likely to be encountered and indicates safe scaled distances to be employed between dragline and blast.

Jan 1, 1979

By J. A. Eisele, D. L. Pool

"The Bureau of Mines has developed a particle agglomeration technique to improve the flow of leaching solution through heaps of low-grade gold-silver ores which contain clays. Benchscale experiments and industrial practice have shown that the percolation rate of cyanide leaching solution is greatly enhanced by mixing the ore with Portland cement as a binder, moistening the mixture, mechanically tumbling to form agglomerates, and aging before heap building and leaching. A slight modification ofthe technique allows its application to precious-metal-bearing tailings, which cannot normally be treated by heap leaching because they are too fine. IntroductionMany low-grade gold and silver deposits and tailing materials from former mining operations in the western United States are potential sources for precious metals. These sources are too low grade or too small to support the capital cost of a conventional cyanidation plant but have stimulated the development of lowcost procedures, such as extraction of the precious metals by heap leaching with cyanide. The Bureau of Mines has investigated methods to improve the recovery ofgold and silver by heap leaching these low-grade materials.For heap leaching to be successful, the crushed and stacked ore must have good permeability so that uniform distribution of the cyanide leaching solution through the heaps can be achieved. Some of the most difficult gold and silver ores to treat by heap leaching are those containing excessive amounts of clays, or fines generated during crushing. Excessive amounts of slimes, generally minus 50-micrometre or 270-mesh Tyler sieve size particles, in the heap feed will slow the percolation of the leaching solution, cause channelling, or produce dormant or unleached areas within the heap, resulting in long leaching periods and low extractions. In extreme cases, the clays or slimes can seal the heap and cause the leaching solution to run off the sides of the heap rather than through it."

Jan 1, 1987

By J. J. Gillman

"The coal deposits from Cape Perce on Cape Breton Island have been known to supply the coal requirements of the people living in or visiting the area for close to 300 years.A major block of coal has been identified off Cape Perce, which has several seams from which coal can be taken. The initial development by the Cape Breton Development Corporation will be in the Harbour Seam and constitutes the Donkin-Morien Development Project.The CBDC's confidence in this indicated resource is based on its knowledge of the Sydney Coal Field and from boreholes driven into the block during the summers of1977, 78 and 79. In 1980, further geological data were gathered from surface drilling and an intermediate-depth high-resolution seismic survey. The surface facilities for the Donkin-Morien Development Project will be located on the northern half of the cape, with access declines extending 3.9 km in a north-northeasterly direction to the Donkin block of coal reserves. The development has the potential of supplying all the coal needed f or the future electrical power generation requirements of Nova Scotia for many years to come.The planned mine, for which a project definition study has recently been completed, will have a production rate in excess of 3 million tonnes per year.IntroductionAt the Second CIM District 1 Meeting held in Halifax in October 1980, a background paper on Phase II of the Donkin-Morien Development Project was presented. The project involves a 3.2-million-tonne, saleable, underground coal mine. At that time, the chronological sequence of events had unfolded, starting with the initial boreholes through to the feasibility study, and on through site clearing and site preparation. This led to engineering design contracts for the portals and the two tunnels to be driven to intersect with the Harbour Seam close to 4 km from their entry point."

Jan 1, 1982

By D. Lauzon, H. de Ruiter

"In 1988a decision was taken to design and install a computerized mine monitoring and control system. This system had to monitor and control all pumping and ventilation underground. The operation of the mine air heating, using waste heat from the mine water and compressors, was to be part of the system. It ultimately also had to interface with the four existing Canadian General Electric Series 3 PLC's which controlled the No .3 shaft loading pockets. Beside operational control and trouble shooting, the system is a valuable tool in energy management and ultimate savings are estimated at $50,000 per year.The final equipment selection was a General Electric Series Six PLC on surface with a total of 17 Series One Plus and Juniors PLC located underground. Data is transferred through a two-pair shielded cable using modems. Both analog and digital functions are being utilized.The basic monitoring and control system was commissioned during 1989and, due to a higher level of technology today, further improvements have been planned for the future. The system was designed by Walter Dow together with Gordon Champion of D.G. Champion Engineering Ltd. of Toronto. Advice for the ventilation part of the project was obtained from Maurice White, Independent Ventilation Consultant.The Ministry of Energy, Mines and Resources and the Ministry of Energy of Ontario approved this project together with the waste heat recovery project to qualify for a grant of$135,000 under the Enerdemo-Canada program.IntroductionThe Macassa mine is a narrow vein gold mine situated about 2 km west of the town of Kirkland Lake in northeast Ontario. The mine has been in continuous operation since 1933 and a total of about 3.0 million ounces have been recovered out of 6.6 million tons of ore ."

Jan 1, 1991

By A. A. Ruitenberg, C. J. Morrissy

"The Lake George antimony deposit comprises a system of stibnite-bearing quartz veins that cut Silurian greywacke and slate. The stibnite-bearing ore zone is in part enveloped by a uraniferous zone.The ore-bearing quartz vein system occupies an easterly striking, gently north-dipping fracture system that cuts across north-northeasterly trending gently southwest-plunging, tight Acadian (early Middle Devonian) folds. This vein system continues at depth into a siliceous skarn zone intruded by altered granite porphyry dykes, which constitute probably a late phase of the Hawkshaw granitoid intrusion to the north.Most of the ore occurs in a northeast-plunging, trough shaped vein structure that formed where the vein system (gently north-dipping) intersects the axial surf ace zone (steeply northwest-dipping) of an Acadian synform. The trough shaped structure resulted from deflection of the fracture zone (containing the vein system) by competent beds.Emplacement of the quartz-stibnite veins was preceded by, and is in part penecontemporaneous with, the formation ofa micaceous-argillaceous alteration halo, which in turn intersects a patchy biotite alteration zone.The hypabyssal intrusions associated with the Lake George deposit probably represent a late phase (early Carboniferousr) of the nearby Hawkshaw intrusive granitoid complex. IntroductionThe Lake George Antimony Mine is situated 40 km southwest of Fredericton and 2.5 kin north of Lake George, New Brunswick (Fig. 1). The mine is owned by Consolidated Durham Mines and Resources Ltd.Shaw (1940) described the early history and development of the mine. In subsequent years, available drill cores were relogged by several geologists. Much new information became available when an extensive diamond drilling program (Kidd , 1970) was started by Consolidated Durham Mines and Resources Ltd. in 1970. A study of the geology and economic potential of the deposit was made by Glover (1973). Abbott and Watson (1975) made a study of the ore mineralogy. Available drill cores were relogged and a preliminary study of the fracture system in the mine was made by G.A. Pierce and A.A. Ruitenberg during 1976. Outcrops in the area sur rounding the mine are extremely sparse.Between 1976 and 1979 the present authors made a detailed study of the mine workings, available drill core and regional structure in the vicinity of the mine, with results set forth in this paper. The regional geologic setting of the deposit, the geometry and structural controls of the ore zones, and the mineral zonation and rock alteration are emphasized."

Jan 1, 1980

By J. H. Archibald

"This paper describes the use of vector analysis for determining the intersection of mineral deposit veins. The mathematical evolution of the analysis is outlined.IntroductionMany mineral deposits can be characterized by sets of intersecting veins. Often a vein will have a steep dip and may intersect with another similar vein. Finding the intersections of these veins is usually done by graphical means. Structural geologists, by the methods of descriptive geometry, can usual ly predict where intersections of veins will occur. This method normally requires accurate drafting and layout of the problem and does not always lend itself to solution in the field.Another method for solving this problem involves the use of vector analysis, which is easily adapted to hand-held programmable calculators. It is assumed at the outset that the reader is familiar with the dot and cross products used in vector analysis. Two excellent references are cited at the end of this note for convenience.A plane, in general, is defined by three points. The points of interest here are the points where three vertical drillholes penetrate the vein, or plane, in question. The elevations of these three points are best referred to sea level. This requires knowing the elevation of the collar of the drillhole above sea level and the drillhole depth from the collar to the vein. The elevation of the intersection point is then found by subtracting the hole depth from the collar elevation. These three points now define the plane of the vein. A similar set of three points will define a second vein, and it is our object to show analytically their intersection if it exists."

Jan 1, 1983