Search Documents

By C. G. McLachlan

Abstract This paper deals with the application of the cyanide process to recover gold from a pyrite concentrate produced by means of differential flotation. This concentrate before cyanidation contains from 0.09 oz. to 0.14 oz. gold per ton, of which only about 60 per cent is recoverable. The rest is so fine that it remains interlocked in the pyrite and therefore is not acted on by the cyanide. The concentrate also contains about 15 per cent pyrrhotite and 0.4 per cent chalcopyrite, both of which are cyanicides. The cyanicidal effect of the pyrrhotite is inhibited by preacracing the pulp with lime, and maintaining a high lime alkalinity during cyanidation. The effect of the chalcopyrice is reduced as far as possible by removing those particles which are free by means of a further flotation step immediately prior to cyanidation. This involves the flotation of some very fine material. After nullifying as far as possible these two cyanicides, the concentrate is cyanided directly, i.e., without being roasted. This leaves the pyrite available for subsequent sale as a source of sulphur dioxide and sulphuric acid, and the entire residue of the cyamde plant, amounting to about 500 tons per day, 1s now being disposed of in this way. Prior to deciding on direct cyanidation, a number of laboratory roasting tests were made. These showed chat, 1f proper control were exercised, a better recovery of gold could be effected from the roasted product than by the direct method of treatment. The tests also showed that the capital cost o the plant would be much higher than that needed for the procedure adopted. The possibility of subsequently selling the pyrite for its sulphur content would also have been eliminated. Introduction A previous paper has described in considerable detail the application of the flotation process to improve gold recovery from Noranda's milling ore, and in so doing has covered the production of an auriferous pyrite concentrate. The present paper deals with the recovery of gold by cyanidation from that concentrate. This gold, though intimately associated with the pyrite, can, for metallurgical purposes, be considered as all occuring in the native state.

Jan 1, 1946

By R. S. Douglas

Introduction During the past few years, a number of changes in the mine operations at Copper Mountain have taken place. The modernization and mechanization were necessitated and given impetus by wartime and other conditions, which were: (1) The urgent need for copper for wartime purposes. (2) The scarcity of skilled labour for underground work. (3) The increase in labour and supplies cost. (4) The necessity of finding ways and means of increasing the output per man-shift, because of the scarcity of skilled labour and the rising cost of labour. (5) The desire to increase safety measures, reduce the silicosis hazard, and aid mine ventilation. (6) The desire to improve the general working conditions in the mine for all workmen. (7) The desire to reduce the amount of dilution in the ore stream by a more selective yet highly productive method of mining. To this end, mining with diamond drills, and transferring broken ore with slusher hoists, appeared to be the answer to the problem. After considerable discussion and estimation of costs for comparison with those of the operation as carried on at that time, the proposed methods were tried out and, in practice, gave very gratifying results. Reference at this point is made to the paper written by C. H. Brehaut, W. N. Taylor, H. A. Shannon, and R. S. Douglas, which was published in the September, 1945, issue of Mining Technology, by the American Institute of Mining and Metallurgical Engineers, Inc., and subsequently in commercial mining journals. Since that time some improvements have been made in undercutting an orebody - the first through experiment and practice, the second through making use of the earth's barodynamic or gravitational forces. It is the purpose of this paper to describe and discuss these later developments.

Jan 1, 1947

By Karl J. C. Harries

"3.1. INTRODUCTIONThis chapter discusses briefly the common law concepts of fiduciary relationship, constructive trust, and breach of confidence. Following a discussion of confidentiality agreements, the last section of the chapter compares and comments on two common law cases, the LAC Case and the Metalore Case. Civil law readers should not ignore this chapter or § 3.5. the comparison as, to a large extent, the concepts and comments are universal, even though the procedures for applying them may vary.1It should be appreciated that, regardless of the legal system, if the Court sees that a wrong has been done, it will attempt to right that wrong, either by awarding monetary damages against the wrong-doer to compensate the injured party or by attempting to make the injured party whole again by such means as negating an agreement (as in the Metalore Case) or returning property to a wronged party (as in the LAC Case). The methodology for accomplishing either of these results will vary with the jurisdiction, and the two are not mutually exclusive.These two Ontario cases have been chosen, not because they are the only ones available – they certainly are not – but because both are relatively well known within the minerals industry and they deal with problems that may face any explorationist (although it is to be hoped that the facts of the Metalore Case do not represent “normal” behaviour). Each judgment offers useful guidelines, as well as insight into a judge’s approach to problems, the type of information he expects to receive, how his mind works, and, particularly in the Court of Appeal judgment in the Metalore Case, how he might reason through and “justify” his decisions.3.2. SOME LEGAL CONCEPTS In order to appreciate some of the matters discussed in this chapter, it is necessary to have some idea of the common law considerations of fiduciary relationships, constructive trust, and breach of confidence."

Jan 1, 2003

By W. J. Asselstine

Introduction This paper is prepared from data gathered for a similar paper to be submitted to the United States Bureau of Mines, for publication as one of their information circulars. It covers the history and development of the present milling practice at Premier. The authors wish to acknowledge the assistance and suggestions given during the preparation of this paper by D. L. Pitt, Manager of the Premier Gold Mining Company, Limited; also their indebtedness to various members of the Engineering Staff and of the Accounting Department who have assisted materially in gathering the data used. Location The Premier mine and mill are situated in northern British Columbia, approximately fifteen miles north of the head of Portland canal, in the Salmon River section, about half a mile east of the Alaska-British Columbia boundary line where it crosses die Salmon river. The mill is located on a rather steep hillside on the horizon of the main haulage level of the mine, and is within a hundred feet of the mouth of the tunnel. Both the mine and mill are connected with tidewater at Stewart, B.C., by an aerial tramway (1) eleven and one-half miles in length, which delivers both ore and concentrate to the bunkers at the dock for shipment to the smelters. All mine and mill supplies are transported from Stewart dock to Premier over this tramway, except heavy machinery. Heavy pieces have to be hauled either by truck in summer or sleighs in winter over a good road which runs from Stewart dock to Premier.

Jan 1, 1933

By R. A. Campbell

The electric smelting of five lowgrade Canadian manganese ores has been investigated at the Mines Branch, Department of Mines and Technical Surveys, Ottawa. Ferromanganese, silkomanganese, and spiegeleisen were produced 1by special smelting processes from these ores since the latter were too low grade to be treated by conventional smelting methods. In one case the results were considered to be sufficiently promising to justify the construction of a pilot plant, by the Company concerned, for the further development of the process.

Jan 1, 1956

By M. Nusheh, C. Bumby, A-H. Puichaud

"Vanadium-bearing titanomagnetite ironsand deposits occur along a 480 km stretch of the west coast of New Zealand. In the present study, the leaching behaviour of NZ ironsand was investigated in hydrochloric acid (2–10 M) solution at 50–80°C for 2 h. The resulting leaching liquors exhibited Fe/V ratios in the range 150–180. The distribution of trace element contaminants between solution and solid residue was investigated, and processing conditions have been determined for rapid and efficient dissolution of Fe, Ti and V into the leaching solution. In addition, mineralogical analysis of raw ironsand and leached residues was performed in order to study the leaching mechanism. Samples were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX), X-ray fluorescence spectroscopy, qualitative and quantitative X-ray diffraction and inductively coupled plasma mass spectrometry (ICP). Results indicate that the dominant dissolution process follows shrinking particle mechanism. However, ironsand particles containing ex-solution lamellae exhibited a different leaching behaviour compared to homogenous titanomagnetite particles.INTRODUCTION Titanomagnetite ironsand (blacksand) forms Quaternary onshore beach and dune deposits and offshore marine deposits (Figure 1) along 480 km of coastline from Kaipara Harbour south to Wanganui on the west coast of the North Island (Christie, 2016). It attracted the attention of scientists from the earliest times (Galbreath, 1998). The principal minerals in ironsand are titanomagnetite (TTM), ilmenite, quartz and ferromagnesian minerals such as augite, hornblende, diopside, and olivine with smaller amounts of rutile and apatite (Mauk, 2016).Several large ironsand deposits have been discovered and exploited since the late 1960’s. The Waikato North Head and Taharoa mines are currently operating and they have a 2015 measured resource of 400 million tonnes in total and provide over 2 million tonnes of concentrate per year by simple cost effective magnetic separation process (Christie, 2016; Christie & Brathwaite, 1997). The concentrate contains not only 7–8% TiO2 and 56–60% SFe, but also 0.3–0.6% V2O5, is both a valuable titanium mineral and a source of vanadium. All the production is used for steelmaking industries. The other potential for utilizing more of this resource without requirement of integration into an iron and steel producing plant is to develop a hydrometallurgical route with advantages of higher efficiency along with lower emissions. Currently, there is no existing commercial process capable of extracting all three of these elements as industrial-grade commodity products. Acid leaching of TTM concentrate with higher degrees of recovery and selectivity is a key step in any possible hydrometallurgical route."

Jan 1, 2017

By Yves Caron

Résumédes travaux effectués De septembre 2009 àmai 2011 ? Plus de 21 000 m de forages complétés en avril 2011 et près de 9 000 échantillons ? 2,7 km de décapage, 52 tranchées et 852 m de rainures ? Estiméde ressources 28 mai 2010 (SGS Géostat) ? Essais métallurgiques en laboratoire (automne 2010) ? Étude économique préliminaire (janvier 2011)

May 1, 2011

By E. W. Shaw

The past year (1950) has been a big one for the oil industry in Canada, with new records being set in almost every phase of exploration and development activity. New highs were reached in acreage holdings, in geophysical activity, in wildcat drilling, and in field development and production. The only item that did not show a substantial increase over recent years was the amount of reserves added by new discoveries. This was not due to a decrease in the number of new discoveries, however, hut rather to the fact that most of the discoveries were made during the later months in the year and could not be fully evaluated by the year end. The foregoing remarks pertain mainly to activity in Western Canada. In Eastern Canada, operations continued on a modest scale. with exploration drilling down slightly from the previous year but with development drilling and production at about the same level. Returning to Western Canada, it is observed that the general exploration play was one of expansion and intensification. The issuing of new petroleum and natural gas regulations by the province of British Columbia precipitated a moderate entry of companies into the northeastern part of the Province.

Jan 1, 1951

By W. M. G. Heeley

In the province of Alberta the coal measures dip at so many different angles, between the horizontal and the vertical, that many different systems of haulage are in use. I will, however, only touch briefly upon the general -systems in use, and devote the major portion of this paper to a discussion of endless-rope haulage and its adaptibility to various conditions in coal mines; dealing in particular with the endless-rope haulage that was installed at Brule during the month of August 1923. In coal seams that are approximately level, and newly opened, hand-putting or tramming from the face is the cheapest, but when the mine is further developed tramming is out of the question, and the use of ponies is the next consideration. The time arrives, however, when mining reaches a point where the economical haulage of coal by horses cannot be done profitably, and then some system of mechanical haulage must be installed. The installation of any system should be carefully considered before any particular type of haulage is adopted, because a great deal depends upon the grade or dip of the seam. Motor haulage is impossible to operate profitably on a grade of over 6 per cent and, while it is possible to use ponies, on short runs, up to 9 per cent, some other means of main and secondary haulage must be installed when a 9 per cent grade, is exceeded. I will, therefore, deal first with secondary haulage, because even though a main haulage is established, secondary haulage can be used to feed the main haulage.

Jan 1, 1925

By F. R. Archibald

SINCE the opening of the Beattie mine, in 1933, the concentrate produced by flotation has been considered refractory. As the gold extraction by cyanidation was poor, the concentrate, during the first four and a half years of operation, was shipped to a smelter for further treatment. After the installation of the cyanide plant, in 1934, seventy per cent of the gold in the concentrate was recovered before shipment to the smelter. In 1937, a roasting plant was built so that treatment might be complete at the mine. Much experimental work had been done by a number of investigators prior to the installation of the roasters, but none of them had seriously attempted to identify the causes of, or the elements responsible for, the refractory behaviour of the concentrate. Intensive investigation in this direction commenced in the Beattie lab-oratory in July, 1938, has led not only to the identification of several causes contributory to the refractory behaviour, but also to revisions in procedure and principles with respect to roasting Beattie concentrate in particular and arsenical concentrates in general. The accuracy of the identification of these causes and the soundness of the principles is borne out by interpretation of roasting plant records, by improvements and simplification since applied. to plant operation, and also by laboratory and test-plant results on arsenical concentrate produced by another mine. It is the purpose here to present an account and interpretation of the laboratory investigation, together with a correlation of laboratory and plant results. Incomplete extraction of the gold by cyanidation after roasting is due primarily to the nature of the material roasted, and secondarily to the manner in which it has been roasted. There is a possibility that better extraction may be obtained by improvements in both particulars.

Jan 1, 1939

By E. R. Mitchell

When we grow up in an urban environment and choose to become a part of a way of life, it is sometimes difficult to appreciate the cost of this decision in terms of pollution. Explained in this article is our dependence on technology and the amount of pollution that technology produces. Inventories of air pollution on both a personal and a national basis are given so that the reader may judge the magnitude of the problem. In doing so, it is hoped that the reader will understand the need for a responsible attitude toward pollution by everyone and how he can make a personal contribution.

Jan 1, 1971

By Belinda Campbell

Tools for Consistency 1. GIS Web Site 2. National Project Management System 3. Site Grouping Approach (721 PIDs) 4. Mine Reclamation Standing Offer Agreements ?Contracting tool 5. Remedial Objectives Guidance Document Background ?CBDC (now ECBC) is a Federal Crown Corporation and falls under federal jurisdiction. ?When it stopped mining coal, CBDC turned its attention to cleaning up and closing out its industrial sites. ?Public Works and Government Services Canada is common service provider to the GoC. ?Expertise in environmental, engineering, IT, project management, communications, GIS, real property management.

May 1, 2011

By Gilles Tremblay

The legacy of orphaned/abandoned mines, with their associated environmental liability, human health concerns and the financial costs of clean up is a serious issue facing Canada. In 1999 and 2000, a number of stakeholders put forth requests to Mines Ministers to establish a joint industry-government working group, assisted by other stakeholders to review the issue of abandoned mines. The Ministers supported this initiative and asked that a multi-stakeholder workshop be organized to identify key issues and priorities. The Workshop on Abandoned Mines, held June 2001 in Winnipeg, developed consensus, guiding principles and recommendations that were presented at the Mines Ministers? Conference, September 2001. Ministers agreed on the importance of a large-scale program for the rehabilitation of orphaned/abandoned mines sites. A multi-stakeholder Orphaned/Abandoned (O/A) Mines Advisory Committee was formed and a plan was developed to study various issues relating to the implementation of remediation programs across Canada. Three task groups were formed to address the following key areas: Information Gathering; Community Involvement; and Barriers to Collaboration. The presentation will include a summary of the results of the three projects and the future work plan for the program.

Nov 1, 2002

By I. M. R. Duarte, J. A. Rodrigues-Carvalho, F. R. S. Rosa, A. B. Pinho

"This paper aims to contribute to the knowledge of the mechanical properties of the shales and greywackes which constitute the flysch-type deposits of the Baixo Alentejo Flysch Group, in the south of Portugal. These formations are flysch-type deposits constituted by sequences of usually thick greywacke beds alternating with thin shale beds, which include sometimes intercalations of conglomerate beds. All the sedimentation of these flysch formations was controlled by tectonics. At the same time, should have occurred along with the first Hercynian deformation phase, a low-grade metamorphic event (chlorite zone), that affected these flysch deposits. This study highlights the influence of anisotropy and heterogeneity of these flysch rocks on their physical and mechanical characteristics. The anisotropy verified in some physical properties and on mechanical properties, due to the foliation makes difficult the sample preparation for the laboratory tests. Besides, it induces a scattering of the properties values measured, as for example, the strength and the deformability. The heterogeneity is related to the main features of these geological formations, which are constituted mostly by thinly stratified greywackes and shale beds, which sometimes may affect the results of the laboratory tests making them less representative. The study is made by using both shales and greywackes that constitute these flysch-type deposits in order to evaluate their geotechnical properties, mainly of the shales. Samples of these two rock materials, are tested accordingly a laboratory testing programme, which includes which included mineralogical analysis (X-ray diffraction), physical tests (bulk density, porosity, and void index) and mechanical tests (uniaxial compression, and deformability tests). INTRODUCTIONOne of the factors that most influence the geomechanical behavior of rocks, as well as rock masses is the anisotropy. The word anisotropy comes from two Greek words ""anisos"" (meaning uneven) and ""tropos"" (meaning direction). A body or material is considered to be anisotropic, where the same property has different values depending in which direction it is measured, therefore, an anisotropic material is one whose magnitude of the properties depends on the direction in which these are studied or measured. Otherwise, it is about an isotropic material. However, the fully isotropic materials are quite rare in nature."

Jan 1, 2015

"Shales play a major role in the stability of slopes, both natural and engineered. This paper attempts to provide a review of the state-of-the-art in shale slope stability. The complexities of shale terminology and classification are first reviewed followed by a brief discussion of the important physical and mechanical properties of relevance to shale slope stability. The varied mechanisms of shale slope stability are outlined and their importance highlighted by reference to international shale slope failures. Stability analysis and modelling of anisotropic rock slope masses are briefly discussed and the potential role of brittle rock fracture and damage highlighted. A short review of shale slopes in open pits is presented.INTRODUCTIONShales have been stated to form approximately 58% of sedimentary rock so it is not surprising that they are frequently encountered in both natural and engineered slopes. They represent challenging environments for slope stability due to the wide variation in their engineering properties, their changing behaviour with time due to geomorphic processes and the variation in the failure mechanisms as a function of both stratigraphy and tectonics. An extensive body of literature exists on the terminology and classification relevant to shales; it is not possible in the scope and length of the current paper to review these works in detail and the reader is referred to Farrokhrouz and Asef (2013), Bell (2000) and Goodman (1993) for detailed discussions. It is arguably the case that no universally accepted classification of shales exists today and depending on the field of application the terminology varies widely. Shales in slope stability, for the purpose of this keynote paper, are taken to include material varying in properties from weak rocks to soils and therein lies one of the most challenging aspects in shale slope characterisation for engineering purposes. They have been classified as “rock-like” or “soil-like’, (Underwood 1967) or compacted and cemented, Table 1, Yagiz (2001). Classifications have considered numerous factors including composition, cementation and a wide range of engineering properties.The propensity of shales to degrade with time due to geomorphic processes has resulted in an important aspect in their classification, that is, the attempts to incorporate slaking, durability and swelling and softening behavior through purpose developed testing methods (Gamble 1971, Morgenstern and Eigenbrod, 1974). Figures 1 and 2 show examples of terminology used to describe argillaceous materials and some proposed engineering classification schemes (Grainger 1984 and Bott 1986). Corominas (2014) provides a recent classification of argillaceous rocks and their durability relating five stages of slope deterioration to the texture of the rock on Ternary diagrams. No attempt will be made here to discuss the merits of the proposed terminology and classifications, suffice it to say, that the controversy and flux surrounding these issues is a strong indicator of the complexities in the behavior of these materials. In this paper the author will consider slope stability in the materials indicated in Table 1, Figures 1 and 2 without undue focus on terminology. At the lower strength limit of shales the engineer must design slopes using the principles of soil mechanics which may vary from the simple Mohr Coulomb plasticity constitutive criterion to modified critical state models, some even attempting to incorporate softening behaviour in the weaker clay shale materials. Given the transitional nature of shale materials several workers have treated overconsolidated clays and clay shales using concepts such as peak and residual shear strength, brittleness index and softening. Martin and Stacey (2013) provide a useful review of the importance of weak rocks in open pit mining, with mudrocks as a specific member, and note the importance of delayed failure, progressive failure and loosening in the stability of"

Jan 1, 2015

By Stefan Boshkov

THE ADVENT of mining at great depth has brought to the fore the question of stresses around mine openings. The many-pronged attack on this problem is certified by the accelerated appearance, in the mining literature, of articles on various topics related to this subject (1). Whereas it may be agreed that we, of the mining profession, have fallen woefully behind in research and the development of an understanding of this important facet of the general problem of mining, it must also be accepted that the analysis of the stresses in a mine structure is usually more complex than is the case in the majority of structures encountered and dealt with in civil engineering. Whereas homogeneity and isotropy are readily acceptable for most metals, such properties are but crudely approximated in rocks. Whereas the external loads on a structure in civil engineering may be readily determined, those on a mining structure are subject to ?conjecture. Whereas the limits of the structure may readily be defined in civil engineering, the boundaries of the mining structure are, in most cases, indeterminate, and subject to intelligent guesswork, at best.

Jan 1, 1956

By R. I. Cavanagh, A J. Last

THE USE of higher grade charges in blast furnaces in the form of sintered or pelletized concentrates has been increasing rapidly. The question of beneficiation of iron ores for this purpose is therefore receiving much attention as more deposits are developed. Many iron ores may respond well to magnetic roasting procedures followed by magnetic concentration, however, in most cases other more standard ore dressing methods are competitive and cheaper. For magnetic roasting as applied to iron ore beneficiation, the present question is "Can it be economically justified in situations where it appears to produce good results?" The following collection of information on the general status and operations of magnetic roasting methods may be helpful in considering this question. Magnetic Roasting Magnetic roasting involves the transformation of non-magnetic iron oxides, hydrated oxides and carbonates by means of heat and suitable

Jan 1, 1961

By T. Adamcewicz

The province's lignite resources lie mainly in the south, extensions of the much larger deposits in Montana and North Dakota. Because of planned additional capacity, conventional steam power generation will probably remain as the dominant resource usage for many decades. Conversion of coal to other energy forms is receiving emphasis and in the future will compete with steam power generation in terms of quantities used.Economic deposits, minable by present-day technology, have been generally defined. Because a large percentage of the total lignite resource is in seams containing multiple partings, future extraction will become much more difficult and capital intensive.Increased public involvement will ensure that the impacts of future coal mining and usage operations are compatible with environmental and social objectives.

Jan 1, 1982

By R. L. Bailey

"The Acheson D-3 Pool was discovered in August 1950, and contains 88 producing oil wells on 40 acre spacing. Initial oil-in-place was 118 million stock tank barrels and initial well potentials averaged 2,000 barrels per day.In early 1956 studies of hydraulic interference between the Acheson and Leduc D-3 Pools were conducted on the Carter Petroleum Reservoir Analyzer. These studies indicated that the natural water drive to Acheson would be incapable of replacing reasonable withdrawal rates over the life of the pool. To avoid shrinkage losses a scheme of pressure maintenance by water• injection was therefore instituted in March 1957.This pressure maintenance scheme is notable because pressure is being effectively maintained by high volume injection through one well located on the flank of the pool. Close control on reservoir behaviour is maintained by regular bottom-hole pres-sure surveys and observation of water cuts on producing wells. No evidence of pressure gradients or channelling of the injected water has been observed to date, and the water-oil contact has remained level over the whole field. It is possible to control the average reservoir pressure within very close limits by varying the rate of fresh water injection.Ultimate recovery estimated from the rise of the oil-water contact and calculated water influx to December 31, 1958, is 335 barrels per acre foot, or a total of 91.4 million barrels from the pool. This compares to 217 barrels Per acre foot or a total of 59.4 million barrels indicated from laboratory test data."

Jan 1, 1961

By M. B. McClenaghan, O. P. Lavin, Ian Nichol

"Abstract-Exploration in most areas of Canada has to contend with problems posed by glacial overburden. In many areas exploration for gold has been based on the sampling of tills, frequently by deep overburden drilling, and analyses of heavy mineral concentrates. Notwithstanding the significant role that till geochemistry has played in the discovery of some important gold deposits over the last few years, increased appreciation of the nature of the glacial history and stratigraphy and the character of gold within till has led to the recognition of a number of ways whereby the effectiveness of exploration can be improved upon.In order for till geochemistry to be useful in exploration, a number of conditions must be fulfilled, including:1. mineralization, or alteration halo related to mineralization, subcropping at the bedrock /over­ burden interface; 2.glacial erosion and dispersal of a recognizable signature of mineralization into the glacialsediments; 3, preservation of glacial sediments containing this geochemical component (trace metal or mineral) at positions subsequently selected for sampling (normally drill sites); 4. correct identification of specific till units and associated ice movement history; 5. collection of adequately large and representative samples; 6. appropriate sample preparation and processing; 7, appropriate geochemical analyses; and 8. correct data processing and interpretation.While we have no control over the first two geological conditions, and only limited controlover till availability, we can control the quality and thoroughness of sampling, sample identification, sample preparation, analysis and interpretation. In particular attention needs to be focussed on obtaining a large enough sample to be adequately representative, an unbiased sample must be collected, together with appropriate sample processing, analysis, data processing and interpretation. It is considered that by modifying or extending existing approaches to gold exploration the chances of exploration success can be increased. In particular, analyses of both the heavy mineral and minus 63 ?m fractions of till is recommended because gold in till may occur in different size fractions."

Jan 1, 1992