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By T. H. Ueng, S. D. Thompson, Y. J. Wang

"INTRODUCTION There is considerable interest among mining companies and government agencies in finding new ways to better control the generation and dispersion of respirable coal dust. Mine face ventilation generally has been considered the most effective tool for lowering the concentrations of respirable dust. Unfortunately, only a limited amount of research has been undertaken to determine the relationships between the various face ventilation parameters and the dust dispersion patterns. If these relationships are better understood, more efficient ways of controlling dust generation and dispersion may be evident. A practical and economical way to gain more in-depth understanding of these relationships is through scale model studies. Past research (1, 2, 3) has substantiated that scale models can be successfully used in studying ventilation parameters provided that geometric, kinematic, and dynamic similitues are maintained.To better understand face ventilation and dust dispersion, a 1/5 scale model of a room and pillar mine face was constructed. This model was then used to conduct experimental investigation on two ventilation parameters. The parameters which were examined included the line brattice distance from the face and the air quantity. The values of these parameters were varied in numerous experiments so that their effects on dust dispersion could be measured.The experiments of this study were unique in two ways. First, two different substances were used to simulate the respirable coal dust. Experiments were conducted with a tracer gas (methane) serving as the dust simulation substance. They were then repeated with an actual dust (Arizona Road Dust) replacing methane as the dust simulating substance. In previous scale model studies, the dust simulation substance has been limited to a tracer gas such as methane. The validity of using a tracer gas to simulate dust is not clearly known yet. The other unique thing about these experiments was the number of points measured for methane (or dust) concentration. Twenty five points in a grid arrangement were measured during each experiment of this study. The number of points measured for concentration in other studies has generally been very small (often 2 to 4). It is difficult to obtain an accurate assessment of how the ventilation parameters are effecting dust dispersion when only 2 to 4 points are measured."

Mar 1, 1989

By C. J. Edmonds

Of the gold mined in Canada over 90 percent is extracted from the ore by the process of "cyanidation". In this process crushed ore is treated with lime to provide "protective alkalinity" and cyanide, usually in the form of sodium cyanide. The gold is dissolved in the cyanide solution, which after further treatments for clarification, is precipitated by the addition of zinc dust. Wastes from the process consist of tailings which will contain cyanides. Water consumption, mill size, effluent quantity and quality are depicted in transparency (1). It should be noted that as far as the wastes are concerned it has been impossible to postulate a typical situation. Variation from the above data will occur. A summary of data from tailings pond effluents is presented in transparency (2). The figures in parentheses indicate the usual range of values for the parameter.

Jan 1, 1973

By S. K. Kawatra

In this paper three methods of on-stream analysis 1) Radiometric techniques, 2) X-ray tube techniques and 3) Neutron activation method are reviewed. Advantages and disadvantages of each method are discussed.

Jan 1, 1984

By Changsheng Song

With increasing depth of coal mining in China, the number of coal and gas outbursts has been increasing for years. By means of destressing the protective seam, the gas in the protected seam is drained to reduce gas concentration in the high gassy seams, thus ultimately attaining simultaneous extraction of coal and gas. Base on the simulated material scale modeling and numerical simulation, the protective seam mining method was practiced at No. 8 coal mine in Pingdingshan city. After extracting the No. 15 seam, the overlying strata movement and the deformation of No. 9-10 protected seam were studied. The experiments showed that it was feasible to destress the protected seams with large interburden thickness. As the protective seam was being mined, the protected seam experienced dynamic movement process and the change in vertical stress in the No. 9-10 seam assumed ?W? shape. When the face had advanced 656 ft (200m) from the setup room, the No. 9-10 seam was fully destressed, resulting in easy gas drainage in the destressed zone. Recommendations on mining sequence of multiple seams mining in the Pingdingshan coal areas were made.

Jan 1, 2008

By D. Babich, L. Alcorn, E. Spencer, A. Smith

Noise is one of the most pervasive health hazards in mining. A compilation of Mine Safety and Health Administration (MSHA) noise survey data for Fiscal year 1990 shows that approximately 40% of the total samples taken for longwall occupations exceeded the Permissible Exposure Limit (PEL) of 100% [Gigliotti et al. 1991]. In order to properly determine workers’ exposures on longwall coal mining systems, it is necessary to provide accurate baseline measurements for these mining systems. This research was designed to develop guidelines and test procedures for identifying all noise sources that are major contributors to the underground noise exposure of longwall coal mining system workers. Once the high noise sources are identified, promising engineering controls can be tested and evaluated to reduce the noise of the sources. The measurement system used to analyze the noise sources included stationary dosimeters in a documented repeatable pattern and a time-motion study of the cutting cycle and operator’s work cycle. Significant results from the underground measurements show that the highest sound levels recorded are at the stageloader discharge segment and tailpiece controls and remained at about the same level throughout the test.

Jan 1, 2007

By B. B. Gottsberger

IT SEEMS strange that so many years after the pas¬sage of the first acts requiring registration or licensing of engineers, so few members of the mining branch of the profession are aware of what has taken place. Laws regulating the practice of engineering have now been passed in 19 states of this country, and in many others, such legislation has been proposed. That such laws are necessary for the protection of life, health and property, as is stated in most of them, is doubted by many. That the standing of the engineering profession will be improved by them is certainlyy open to question. That such laws are a welcome addition to the regulation of business by governmental agency, is not likely to be a general opinion. That once more, and in spite of appeals to engineers to interest themselves in affairs of government, an active minority has succeeded in imposing its will on a passive majority, seems but too true. However, the laws are there and information regarding them should be of use and interest to those most directly concerned.

Jan 1, 1921

By Elisa Alonso

Manufacturing firms that rely on finite resources have a stake in ensuring sustainable materials use. Higher material prices and uncertain material supply, consequences associated with scarcity, can be damaging to firms. Firms have a number of options to improve material sustainability including dematerialization, material substitution and recycling. However, these options require technological capability, capital investments and supply-chain infrastructure; firms may decide to make such investments only if material prices increase. Once decisions are made, the barriers and delays to implementing changes may harm firms. The impact of not reacting to changes in material supply on firms was examined for the case of different platinum-using industries. It was found that taking action is particularly important for firms when limited material availability leads to volatile market conditions. Industries can benefit especially if they ensure process flexibility and have options for changing their material use patterns.

Jan 1, 2010

By J. R. Goode

"The Las Cristinas deposit contains about 10.2 million ounces of gold at a grade of 1.3 g/t. The deposit comprises a layer of fully oxidized saprolite (SAPO), a layer of sulphide-enriched saprolite (SAPS), carbonate leached bedrock (CLB) and carbonate stable or un-leached bedrock (CSB). Gold occurs at about the same level in all lithological groups. The bedrock units contain minor amounts of copper (about 0.1%) as chalcopyrite, while SAPO contains virtually no copper it having been leached and deposited in the SAPS zone.A previous owner started investigation of the Las Cristinas deposit in Venezuela in 1991. Over the next seven years, 1174 holes with a total length of 159 km were drilled, extensive metallurgical testwork, including pilot plant operations, were conducted and feasibility studies were completed. Construction was started in 1997 and again in 1999 but was suspended.Crystallex has been producing gold in Venezuela since the early 1990’s. In 1997, Crystallex acquired Inversora Mael which had held two of the claims to the Las Cristinas concessions since 1986. In September 2002, Crystallex entered into a definitive agreement with the Corporación Venezolana de Guayana, (CVG), to develop the Las Cristinas deposit.An extensive program of studies and testwork was started in early 2003 to determine an optimum development plan for Las Cristinas. Mine Development Associates, SNC–Lavalin Engineers and Constructors, SGS Lakefield Research Limited, J.R. Goode and Associates, and Professor A. Laplante at McGill University acted as the main contractors.Because of the potential value of by-product copper, earlier flowsheets used carbon-in-leach for SAPO, but processed all other ore types by flotation to produce a gold-copper concentrate with cyanide leaching of cleaner tailings to maximize gold recovery. Cyanide recovery was necessitated by the high copper content of the leach feed. Initial studies of available data by Crystallex revealed that direct leaching of all ore types would provide about 11% more gold recovery than the previously selected flotation route with reduced capital and operating costs.Bench and pilot scale studies have confirmed that a SAG-ball mill-gravity-CIL route is very effective for all ore types and will give about 89% gold recovery. This paper describes the recent testwork, discusses the proposed plant design, and presents economic data."

Jan 1, 2004

By D. M. Schubert

As a clean and renewable energy carrier, hydrogen is an important component of most alternative energy portfolios. Hydrogen combines very high energy content by weight with excellent environmental attributes. Since hydrogen reacts with oxygen to produce only water with release of energy, it can be used to power fuel cells, combustion engines, and turbines, without production of greenhouse gases at point of use. However, because of its low volumetric density, storing pure hydrogen is impractical. Thus implementation of hydrogen technologies requires materials that can safely store and release large amounts of hydrogen (1,2). In recent years, the U.S. Department of Energy (DOE) and other governmental agencies around the world sponsored extensive research on hydrogen storage materials, including those based on boron. These efforts have resulted in significant advances in hydrogen storage technologies. Boron materials stand out as leading candidates for hydrogen storage among the many options investigated. Combining excellent hydrogen densities, release rates, and safety characteristics, some boron materials can hold substantially more hydrogen by weight and volume than even pure liquid hydrogen (3-5).

Jan 1, 2010

By B. A. Wilcox, A. H. Clauer

DURING the course of an investigation on the high-temperature creep behavior of TD Nickel* (Ni + 2) vol pct ThO2), it was observed that the creep fractures were similar in appearance to low-temperature ductile fibrous fractures and creep ruptures by cavitation. Microfractographs of fibrous ruptures are typically characterized by a dimpled appearance, with second-phase particles frequently found near the bottom of the dimples.'-4 These somewhat resemble creep ruptures by cavitation, in that fracture occurs by void formation, with the subsequent growth and final merging of the voids to form a complete fracture.' It is the purpose of this communication to describe the creep fracture of TD nickel and suggest a mechanism for the rupturing process. The discussion is relevant to material crept to fracture in vacuo at a constant stress of 18,000 psi, over the temperature range 900" to ll00°C. The material used in this investigation was 1/2-in.-diam bar stock supplied by Du Pont, contain- ing 2.3 vol pct Tho2. The final fabrication treatment consisted of -95 pct reduction by swaging followed by a 1-hr anneal at 1000°C. Transmission and replica electron microscopy revealed that the material had a fibered structure with a transverse grain size of -1 µ and a longitudinal grain size of 10 to 15 µ. Selected-area diffraction indicated that the fiber axis was parallel to (00l), in agreement with the results of Inman et a1.6 The thoria particle size varied from 80 to 1000Å, with an average size of 400Å, and the mean particle spacing was about 1200Å. The remarkable structural stability7 was confirmed by annealing for 6 hr at 1300°C (about ' 0.9 the absolute melting point). Transmission electron microscopy revealed that the only structural change was a slight decrease in dislocation density. Furthermore, recrystallization or grain growth during creep has not been observed. All specimens were annealed in vacuo at 1300°C for 3 hr prior to creep testing. The following times to rupture were obtained for vacuum creep tests at a constant stress of 18,000 psi: 900°C, 854 hr; 930°C,

Jan 1, 1965

By Dr. -Ing. Wolfgang Pietsch

Many primary metallurgical wastes are in the sh.-ape of turnings; borings, chips, dusts, and other particuletes. While such. materials can be easily segregated and/or upgraded to yield high quality ?secondary metals with often known composition for easy recirculation into the production? process; their particulate nature results in various problems. Roller presses are used in an ever increasing number for size enlargement and densification of primary particulate metallurgical wastes for secondary metal recycling. The paper will mention the areas of application from A(luminum) to Z(ink), also including Brass; Cast Iron, lead, and Stainless Steel, as well as dusts from all types of melting and ladle furnaces or converters. Typical systems using roller presses for size enlargement. will be discussed.

Jan 1, 1995

By Johnna Muinonen

"The Thompson Mill processes ores from the Thompson and Birchtree Mines. While the Thompson ore has very little magnesium containing gangue, the Birchtree orebody consists of veins of massive sulphide in a rock matrix that contains a high proportion of magnesium silicate minerals. A significant fraction of the magnesium is floatable, which lead to MgO levels varying from 3-11 wt% in the Birchtree concentrate. The magnesium in the concentrate causes a higher operating temperature in the smelter, reducing furnace life.Birchtree ore represented 20-30% of the mill ore receipts prior to October 2003. Since then the fraction of Birchtree ore has increased to 50%. A reduction of the MgO in concentrate to less than 3% in the total mill concentrate was required to allow safe and economic smelter operation.In October of 2002 a miniplant was set up to simulate the Birchtree plant circuit. Several flow sheet modifications were tested that led to a proposal for a circuit having increased cleaning capacity for the scavenger concentrate and a recleaner on this concentrate. Addition of CMC in rougher cleaner feed was also found to be required. The solution was confirmed through pilot plant testing in the mill in December of 2002. A full-scale installation was designed, engineered, and installed between February and September of 2003 with commissioning in September and October of 2003. Target metallurgy was achieved one week after start-up on slurry to coincide with the Birchtree Mine tonnage increase. This paper highlights the development, design and commissioning stages of the project.The new MgO rejection circuit has successfully allowed the processing of Birchtree ores producing concentrate consistently below 3% MgO. In addition, the new circuit increased overall nickel recovery in the mill.INTRODUCTIONThe Thompson Nickel Belt located approximately 700km north of Winnipeg was discovered in the early 1950’s. Inco first produced nickel from the area in 1960. Over the years the mill has processed several ores from different ore bodies in the area. Currently the Thompson Mill processes two significantly different ores from two mines, Thompson and Birchtree. The Thompson ore is a massive sulphide orebody hosted in schist, containing feldspars, quartz and biotite. Thompson Ore is characterized by high nickel recoveries and clean, low MgO containing concentrates (<2.5% MgO). The Birchtree ore is ultramafic and contains a high percentage of Mg-silicates such as serpentine, chlorite, biotite, amphiboles and talc. Some of these Mg-silicates report to the nickel concentrate and prior to commissioning of the MgO rejection circuit the Birchtree nickel concentrate typically contained 5-8% MgO"

Jan 1, 2006

By Ken Norris

"Campbell Mine which has been in continuous operation since 1949 has undergone numerous operational changes in the past 3 years. This paper describes the process changes which have occurred at the Campbell Mill since 1991. The paper discusses the engineering, construction and startup of the effluent treatment circuit, the new oxide filtering and merrill-crowe precipitation circuit, and the changes to the pressure oxidation circuit. Particular attention is paid to startup problems and solutions to these problems. A review of the benefits and results of these process changes is also discussed. Future changes are also briefly reviewed with anticipated goals and expectations.IntroductionCampbell Mine is a gold mine 100% owned and operated by Placer Dome Canada. It is located in Balmertown, Ontario which is located 300 kilometres northeast of Winnipeg, Manitoba. The Campbell Mine has been in continuous operation since 1949, producing nearly 8,000,000 ounces. In 1993 Campbell Mine is budgeted to produce 289, 750 ounces of gold at a cash cost of $157 US/ounce. Daily mill tonnage is budgeted for 1,430 tons/day but has milled as high as 1,600 tons/day on a consistent basis. Recovery in 1993 is 93.4% and is budgeted to average 94.5% in 1994.In the 1992 edition of the proceedings of the Canadian Mineral Processors conference I described the changes that were made at Campbell starting in 1989. This paper continues where the 1992 paper ended and discusses the changes to the Campbell mill since that lime. The changes to Campbell since January 1992 have been numerous with capital expenditure in the mill exceeding $14.1 million. This paper describes three primary projects since that lime: the effluent treatment project ($5.5 million), the oxide leach/filtering and merrill-crowe project ($4.6 million) and the pretreatment project ($2.81 million). The focus of this paper is to highlight the justification of each project, the design and engineering, and some of the initial operational problems and solutions applied to those problems."

Jan 1, 1994

The Stability Graph Method is widely used in Canadian underground hard rock mines for open stope support design and is frequently used in the mine planning phase to assess the viability of stope geometries and to determine maximum permissible spans. The Method is well accepted due to its simplicity and suitability to a wide range of mining methods requiring the use of sublevels to access and extract the mining blocks. While this Method is reliable in situations where the maximum induced tangential stress creates adequate compressive stress keeping the face in a state of confinement, the Method fails to reflect the effect of low confinement caused by lower compressive stresses and instances where tensile stresses are developed. In this paper, a new Rock Stress Factor, A?, an update to the original Rock Stress Factor, A, is proposed, which will reflect the impact of low confinement or overstress regime on critical face stability. Two case studies, based on two Canadian operating gold mine shows that using the new Rock Stress Factor A? to predict the stability of stope hanging-wall and footwall gives better agreement with the CMS survey results, compared with the prediction using the original rock stress factor.

May 1, 2011

By T. O. Allen, J. H. Atterbury

Laboratory and field tests during the past five years indicated considerable variation in the penetrating power of commercially available gun perforators. Many of the guns which achieved inadequate penetration in these tests have since been improved. However, recent productivity tests indicated the possibility of inadequate penetration or, at least, ineffective penetration in some wells. Laboratory experiments under simulated well conditions have demonstrated considerable plugging of the perforations, apparently as a result of factors associated with the shooting process and/or the drilling mud in the well at the time of perforating. The restrictions to flow per unit of hole depth caused by this plugging appears to be greater for jet perforators than for bullet guns of comparable diameter; however, because of the greater depth of penetration obtained with the jet guns, the total flow rates appear to he approximately equal. Limited testing with an experimental shaped charge suggests that less shot hole restriction and greater flow rates may result from larger-diameter perforations or other factors related to charge design. INTRODUCTION Gun perforating has been accepted for a number of years as a routine well completion method which is often preferred since it permits more selective operation of producing zones. Nevertheless, questions have continued to arise as to the effectiveness of the communication paths established between the productive formation and the interior of the casing. The basis for these questions has generally been failure to obtain anticipated fluid production rates through gun perforated completions in specific wells. These low productivities, together with the frequent recovery of bullets from well bores, were considered strong evidence of inadequate penetration. Laboratory investigations of the penetration performance of many of the bullet guns available as late as 1948 gave support to these indications. Subsequent electrical analog studiesl,2,3 indicated that the depth of penetration required to provide productivities equivalent to open hole was beyond the capacity of most bullet perforators evaluated in the early laboratory penetration tests. These results, together with the advent of the shaped charge in the field of oil well perforating, stimulated the interest of both oil operators and service companies in gun development. Improvements in gun design resulted in jet and bullet guns which appeared to be capable of providing sufficient penetration for most perforating jobs. However, some wells failed to yield satisfactory fluid production even after being perforated with the more powerful guns, again raising the question as to the effectiveness of the perforating operation. This fact, together with preliminary shooting into targets prepared with formation cores, indicated that factors associated with the perforating process and/or the fluids in the well bore at the time of shooting may reduce effective formation penetration and thereby decrease well productivity. These laboratory and field data prompted another phase in the investigation of the effectiveness of gun perforating: a program to determine the extent and seriousness of perforation plugging under simulated well conditions.

Jan 1, 1955

By C. M. Smith

PILOTED by Cadwallader, Evans, Jr., as chairman, the Coal Division got under way Monday morning for the first of three consecutive sessions. N. F. Patton started the ball rolling with a paper on the economics of anthracite distribution, which was ably discussed by H. J. Rose, W. S. Blauvelt, and others. Mr. Patton pointed out many incongruities in freight rates, dealers&apos; margins, and other factors which are disturbing the distribution of anthracite, one result being that trucks are hauling at least six million tons of anthracite annually, half of which is stolen. In the discussion of the papers the desirability of greater uniformity in the production and shipment of coal from month to month was urged; with larger summer price concessions as a means toward this end. "Performance Expectancy of Domestic Underfeed Stokers for Anthracite," by Allen J. Johnson, brought this important platter down to date by showing the range in capacities and efficiencies to be expected from well-made stokers, and by detailing other of their operating characteristics. One of his most interesting points is that the efficiency of domestic stokers is practically equal to that of handfiring for good installations and operations of both

Jan 1, 1935

Breaks in coal slurry impoundments can threaten the lives and health of area residents, destroy homes and businesses and contaminate water supplies. This dangerous potential looms over coalmining regions in West Virginia and throughout Appalachia. The Coal Impoundment Project was begun in June 2003 to provide an inventory and mapping of active and abandoned impoundments in West Virginia. The project also provides the public with specific information about the impoundments in their communities. It is dedicated to alerting residents of danger and evacuation plans, reducing risk to residents and finding alternatives to impoundments. Since its first year, more than 100 impoundment sites have been added to the project’s Website.

Jan 1, 2005

By Glenn Kosick, John Starkey, Glenn Dobby

"A practical new test has been developed for SAG hardness determination. Using two kilogram samples of minus one inch diamond drill core or crushed muck samples, the Starkey SAG Test has been shown to give accurate predictive information which directly relates to on-stream SAG mill performance. Typical results and test criteria are discussed in the paperAchievements to date include:• Identification of hardness profiles and the location of hard and soft zones in a large ore body.• Accurate prediction of the hardness of a bulk sample by using an adjacent diamond drill hole.• Derivation of a plotted curve relating pilot plant power to laboratory relative hardness.• Demonstration that for every test done to date, the Starkey SAG Test produced a product size distribution identical to that produced in a pilot plant or full scale plant SAG operation.This test can now be used for blast hardness monitoring and short term control of mine production in existing plants and for identifying the proper locations for bulk samples in new projects. In addition, new SAG mill design can now be rationalized in a low cost way to eliminate unforeseen production shortfalls.IntroductionThis paper is presented to introduce the Starkey SAG Test, a practical new laboratory tool for measuring the relative hardness of small ore samples in a semi-autogenous grinding (SAG) environment. The test was first designed for use on diamond drill core samples during the prefeasibility stage of new mining projects, to provide new information about the ore body at reasonable cost. It is a new tool and does not replace existing pilot plant test requirements.The test will also be useful for throughput prediction in existing SAG plants by assisting in short and long term mine planning, where forecasting of metal grades and milled tonnage is used to control mine profitability. Because in-plant hardness testing has previously been unavailable on small samples, this test offers exciting possibilities for SAG mill operations where hardness variation is or could be a problem.The Starkey SAG Test provides the following benefits to the mining industry"

Jan 1, 1994

By Robert Cluff

The Campo Morado precious-metal-bearing, volcanogenic massive sulphide district occurs in a Lower Cretaceous felsic volcanic sequence in a northerly trending belt in the Guerrero Terrane in northeastern Guerrero, Mexico. During upper Cretaceous to Early Tertiary greenschist-facies regional metamorphism, the rocks were deformed strongly into a northeast-verging fold-and-thrust belt. The deposits belong to a low-sulfidation, volcanogenic massive sulphide system formed in a subaqueous environment, and are of the siliciclastic type. Most are on the flanks of felsic domes or in adjacent basins and many are associated with heterolithic volcaniclastic rocks. The Reforma and possibly the El Rey massive sulphide deposits are interpreted to be overturned, and the Naranjo, El Largo, and Estrella de Oro deposits and the El Profundo occurrence to the south are upright. The G9 deposit and the La Lucha and San Rafael occurrences are in an over-thrust plate further to the southwest. In several of the deposits, zinc, lead, silver, and gold are concentrated near the stratigraphic top, and copper is concentrated near the stratigraphic base; copper also is concentrated in replacement bodies near the top of some domes. Major minerals are pyrite, quartz, ankerite, sphalerite, chalcopyrite, and galena. Gold and silver occur in argentian gold, and silver also occurs in tennantite/freibergite and galena. Underlying stockwork zones contain disseminated and vein quartz, pyrite, chlorite, and ankerite, with locally abundant chalcopyrite and/or sphalerite. Exploration since 2004 has enlarged greatly the El Largo and the high-grade G-9 deposits, and slightly enlarged the El Rey deposit. The cumulative in situ massive sulphides for the Reforma, Naranjo, El Rey, El Largo, and G9 deposits exceed 45 Mt.

May 1, 2006

By Bryan A. Bartley

"Jim Macdonald was promoted from Waterworks Engineer to Streetworks Engineer for the Wellington City Council. He thus took over the City quarry and responsibility for its performance. The crushing plant needed upgrading and he thought it would not be difficult to make a crusher to overcome a problem. If he had a longer association with the quarry industry he would have used conventional methods and equipment, so his invention arose from a fresh view of crushing.He invented the Barmac Rotopactor after observing a wear resistant chute with a lining of dead stone trapped above a piece of angle. This idea led to a rotor lined with trapped stone, rotating on a vertical spindle. In trying - a model rotor he observed the impact against a circular rill of stone in half an oil drum and thus was started a very fertile new area of developement in comminution. The writer helped in the developement and shares in the patents. Jim died in January 1982, just as the machine was becoming known and some 200 were in use in various countries. Most were working in hard rock quarries et that time but recent uses have carried the machine into the mining and mineral processing field. This paper is directed at that industry."

Jan 1, 1985