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By Gary J. Fletcher

Mining and processing activities which are proposed on private land, state leases, or unpatented mining claims are governed by numerous local, state, and federal laws which identify the procedures and conditions which must be met before resources can be developed. The respective government agencies responsible for the administration and enforcement of these laws have promulgated supporting regulations and guidelines, and have implemented certain permit and approval processes to ensure compliance. Each exploration project has a unique environ- mental setting and location which further dictates the types of air, water, hazardous waste, and wildlife laws and regulations which must be complied with before development commences. The environmental planning process should be the first step in the evaluation of existing company properties and the potential acquisition of other mineral properties. However. many company don't consider the environmental requirements for a project until the decision is made to develop the property for mining and processing. If a mining company wants to expedite the environmental planning process, it must first develop an in-house process for evaluating the project and determining the environmental approval procedures in the state where the project is located. The first stage of environmental planning involves general information which can set the overall company philosophy for development of projects.

Jan 1, 1987

By Bradford F. Townsend

A study was made on six collapses that occurred during large-diameter tunnelling through weak sedimentary rocks and soil using SES methods in three stages?top heading, bench and invert. The collapsed lengths are between 20 m and 277 m. The collapses were re-mined using essentially the same tunnel-ling method with larger excavation profiles to accommodate the designed remedial measures consisting of ground treatment, pre-support and stronger initial support/outer lining required to carry higher ground loads acting in the collapsed lengths. The paper presents information on the collapses and the design and execution of the remedial measures.

Jan 1, 2008

By Don Dodds

Iron Mountain Mine Rehabilitation Project Brief History The Iron Mountain Mine is located in Northern California approximately 12 miles northwest of Redding. The ore body is a large, very dense pyritic intrusion, discovered in 1860, and initially minded for silver. The silver played out quickly and 34 years later the ore body was mined for copper. Copper mining was scheduled to cease in 1939, but WWII prolonged the closure. After WWII, the pyrite ore was mined to produce sulfuric acid. In 1949 when large amounts of cheaper sulfuric acid were being generated by the oil industry the underground mine shut down. Little was done with the site conditions until 1970 when the U.S. Bureau of Mines began monitoring the pH of the effluent. The initial pH readings were around 2.0. This was lower than anyone expected. Laboratory tests showed that when the ore from the mine was submerged in water, the pH of the water would stabilize above 4.0. However, the pH got steadily lower. In 1989 with the ph around 0.7, the U.S. Environmental Protection Agency (EPA) required the owner to build a capture and treatment facility. During this initial period, the majority of the effort was spent on the treatment plant. The relationship between the mine owner and the EPA was basically an adversarial relationship from the very beginning. In 2001, North Pacific Research was hired to upgrade the capture and control facility. The general layout of the Iron Mountain Mine is shown in Figure 1.

By Bernie W. Martin, Raymond Leray, Christian Criado

Aguas Argentinas,1 a consortium managed by Lyonnaise des Eaux of France and operator of the world’s biggest privatized water supply and waste water collection system for the City of Buenos Aires, a city of 9 million people, was faced with the daunting task of providing new service to 1.6 million more people in the first five years of their 30 year concession. Aguas Argentinas elected to use the Negotiated Compressed Process - NCP - for the fast track implementation of a 15000 meter, 3,5 meter diameter tunnel, a key component of the infrastructure master plan. NCP was developed by Klohn Crippen for the $200 million international railway tunnel between Canada and the United States. The conceptual design of the project was performed by Safege Montgomery-Watson, who engaged Klohn Crippento assist with the NCP, the preparation of the tender documents, and implementation of theproject during construction. The process included the purchase by the client Aguas Argentinas of two sophisticated 4 metre diameter earth pressure balance tunnel boring machines from Herrenknecht of Germany. Construction of the tunnel is being performed by the consortium Wayss & Freytag (Germany) and Sollazzo Hnos S.A. (Argentina). The water tunnel is being built with a one pass, bolted segmented gasketed reinforced concrete liner. The purpose of this paper is to describe a transferable methodology for this innovative contracting procedure, the project organization and quality control plan for this important world class tunnel project which is designed to service one of Latin America’s largest metropolitan areas.

Jan 1, 1997

By Stephen H. Stow

Economically important heavy minerals have been studied in the sediments of offshore Alabama and Mississippi. Sandy samples have been collected from a 200 square mile area from Dauphin to Horn Islands. The minerals concentrate in sediments under 10-35 feet of water and may reach 2.4% by weight. The distribution of total heavies is related to the hydrodynamics of offshore Alabama-Mississippi; the greatest concentrations are in the Gulf where the longshore current is diverted from its westerly flow. Preliminary observations indicate that the distribution of individual minerals can be correlated with wave energy, particle size, specific gravity, and morphology of the mineral grains. The coarser, lighter minerals--kyanite, sillimanite and staurolite--are concentrated in relatively low energy areas in the Mississippi Sound and at the end of Dauphin Island in the Gulf; maximum concentration for each is 34.5%, 6.0% and 43.2%, respectively, of the heavy minerals. The smaller, more denseminerals--ilmenite, rutile, leucoxene, zircon and monazite--are concentrated in high energy areas in the Gulf; maximum concentration for each, respectively, is 42.0%, 5.9%, 9.652, 10.7% and 1.3% of the heavy minerals. On the basis of a minimum concentration of 1% heavy minerals, two areas have been identified and the total amounts of different minerals have been calculated to a depth of 25 feet of sediment. The data are preliminary and in no way indicate recoverable reserves, but they do show that on the order of 20 million tons of heavies exist. These deposits should be termed "indicated resources".

Jan 1, 1975

By Pierre J. Goossens

Since Guild 1 and Snelgrove 2 attracted our attention to the relationships between certain endogenic ore deposits and plate boundaries, an abundant flow of papers appeared in the metallogenic literature concerned with this problem and its application to mineral exploration. Some of the papers only speculate with the formation of specific type of ore deposit 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 Other papers are more concerned with genetic and structural relationships between plate tectonics and mineralization 13, 14, 15, 16, 17, 18, 19, 20 They are philosophical, in that they are generalized and refer to no specific area. Yet it is true that a large part of the world mineral potential is concentrated at the convergence of oceanic and continental plates, for example, around the Pacific. Therefore, the interaction of two plates by either subduction, obduction or slippage likely has an important role for the genesis and/or the (structural) control of these "orogenic" ore deposits. If subduction is the driving mechanism for the generation of igneous rocks 21, 22 and endogenic ore deposits 18, volcanic activity and the nature of volcanic products certainly are the major geologic processes and events to be tested. Fonteilles 23 and Alsac 24 have already emphasized the important relationship between mineralization and the talc-alkaline affinity of the volcanics. The Andean orogen is one of the best areas for testing such genetic relationships. Rich and varied endogenic and volcanogenic ore deposits occur there and plate interaction is still active.

Jan 1, 1975

By G. S. Dobby

High-intensity wet magnetic separators have been successfully introduced into the mineral processing field over the past ten to fifteen years, due largely to rapid advancements in magnet design. Wet magnetic separation, until recent years, was applied solely to the concentration of minerals of high magnetic susceptibility, such as magnetite, at relatively coarse sizes. Now, however, high-intensity separators are capable of treating weakly paramagnetic minerals and have extended the range of treatable particle size down to about one micrometre(1,2). . One of the more recent-high-intensity separators developed is the Kolm¬Marston Marston type high-gradient magnetic separator (HGMS) (3,4) It consists basically of an iron-clad solenoid surrounding a matrix material - a fine, ferromagnetic steel wool or expanded metal lath. A schematic diagram of the device is shown in Figure 1. Large, highly localized, pertebations of the magnetic field are created by the ferromagnetic matrix. It is these field gradients that are instrumental in developing large magnetic forces which act on the mineral particles. Operation of the separator is simple. Slurried sample is fed through the matrix and, depending upon the mineral parameters of particle size and magnetic susceptibility and. the operating parameters of flow rate, field strength and feed weight, some particles will be attracted to and adhere to the magnetized matrix, while the others will flow through the matrix. The separation is completed by later removing the background magnetic field and flushing the captured mineral particles into a separate container. The process can also be applied on a continuous basis (S).

Jan 1, 1977

By Angelus S. C. Owili-Eger

The investigation into the hydrologic and hydrogeochemical influence of longwall coal mining in the Appalachian coal basin was under- taken in response to the need to technically address problems of damaged or impaired well yields, and quality deterioration. Prior to this study, issues regarding reduced aquifer yields and degraded water quality had to be handled in a very qualitative manner. Such an approach would, in the long run, claim a heavy toll on the mining industry. The primary objective of this undertaking, therefore, was to provide sufficient and reliable information base for the determination of the local and possibly the regional effects of longwall mining on well yields, and the hydraulic and hydrogeochemical parameters of the immediate surface and subsurface water systems. Specifically, the program was designed to supply definitive data to answer the following series of questions: 1. Does longwall mining affect the quantity and quality of water in local wells above and adjacent to longwall panels and barrier pillars? 2. If the water quality is affected as soon as mining takes place, does it heal? or if it is not affected immediately, does it change over a longer period of time? 3. How do the aquifer water transmitting characteristics respond to induced physical ad hydrologic variations? 4. What is the extent of the various changes in quantity and quality of the water resources? 5. Should and can standard hydrologic evaluation techniques be used to determine the hydraulic properties of highly fractured zones located within a larger and less permeable aquifer?

Jan 1, 1983

By Williams R. Reynolds

Studies of the northeastern Mississippi bauxites were initiated primarily for the purpose of ascertaining the quality and quantity of the ore. Subsequently, this ore was found to have a rather dubious economic value as was previously suspected but never established in earlier economic reports (1, 2, 3). However, the quality of ore was found to be higher than previously thought. Even though the ore bodies were determined during the early stages of this study to be too thin, small and widespread for commercial production a continuation of the study was not abandoned. On the contrary, the present investigation was intensified concentrating less on the economic application and more on stratigraphy and genesis. Considering the ever increasing demand for aluminum products the northeastern Mississippi bauxite district which includes portions of Tippah, Benton, Pontotoc, and Union Counties may soon become, in spite of inferior quantities of ore, an attractive area for bauxite production. Presently, however, the meager quantity of ore discourages exploitation. On the other hand, these northeastern district bauxites are facies of more extensive units of lignite bearing high aluminum clays, and considering the advances in aluminum extraction from clay these clays may in the future beckon mining interest. The bauxite of the northeastern Mississippi district, mapped as a part of the Betheden Formation (4). has an outcrop trend along the county lines of Tippah and Benton Counties and the extreme western portion of Union and Pontotoc Counties. Studies of exposures and cores stratigraphically positions the outcrop between the middle Midway Porters Creek Clay and the lower Eocene Wilcox sands and

Jan 1, 1977

By Thomas R. Hightower

The Thunderbird plant was erected in Sullivan County in Indiana during 1958-1959. It was first put in operation in March of 1959. At the present time the source of the raw coal is from the Indiana No. 6 seam. The underground operation at present consists of two continuous mining units and two conventional units. The underground is all belt haulage and the first unit with which this paper is concerned is the slope belt. It is a 48-inch-wide inclined belt with 980-foot centers and a lift of 275 feet. The belt is powered with a 350 H, P, motor and has a rated capacity of 600 Tons per Hour. The belt is equipped with a Merrick Scale Company Weightometer, The raw coal moves from the belt to a 6'x12' extra heavy Allis-Chalmers Ripl-Flo equipped with 6" round-hole screens. The over product of the screen is fed into a 10'x20' long McNally- Pittsburg rotary breaker equipped with 4-l/2" round-hole screens. The oversize rock is discharged into a bin that is emptied with a refuse truck. The through-product of the breaker, along with the through-product of the Ripl-Flo, passes either directly to the McNally Giant washbox or to a 36" belt that transports it to a 1000-ton storage bin,' The change from either to the washbox or to the storage bin is made by use of a motorized gate controlled by the plant operator,

Jan 1, 1961

By Mogens Henriksen

In the past decade, numerous urge scale drilling projects have made use of reverse circulation air lift methods. Reverse air lift pumping can be established by injecting gas into a column of liquid; the subsequently decreased density of the gas-liquid mixture allows atmospheric pressure outside the lift conduit to establish flow. The rate of flow can be controlled by varying the gas to liquid ratio. A typical reverse circulation air lift system is depicted in Figure 1. Allen1 has described a number of reverse air lift drilling projects. Although cited examples are generally related to large diameter holes, the method has seen use in other applications such as sand dredging, chemical pumping, water well pumping and continuous coring. One particular benefit obtained with enclosed reverse circulation drilling is elimination of lost circulation. The required air/water ratio for pumping at a given submergence and lift has been established experimentally by Gibbs2. His data, however, do not reflect sensitivity of flowrate to air/water ratio. Further, in Gibbs' work, air apparently is injected continuously along the column of water. This configuration differs from that used in reverse air lift drilling where air is injected at discrete points only. Gas lift theory has received considerable attention over the past decades. Orldszewski3 defined flow regimes in two phase flow. Griffith and Wallis4 determined relative velocities of gas to liquid. Two-phase flow has been studied extensively for oil transport in inclined and vertical pipes by Chierici et a15, Beggs and Brill6, and Gould, Tek and Katz.7

Jan 1, 1977

By A. Habibi

The FMC Westvaco Trona Mine is located near Green River, Wyoming and has an annual production of 4.5M tons. Trona is an evaporite mineral that is processed into several products, mostly soda ash. The underground mine has two active development panels and one longwall (LW) panel. The mining horizon is about 500m below surface and the surrounding strata liberates methane. Three surface-based, blowing fans provide ventilation air as a positive pressure system. The mine operates a 225m long LW face, built by Joy Mining Machinery. Headgate and Tailgate developments are driven with four entries. The recovery room, at the end of each panel, is 8m wide with three access chutes. Additional recovery room support comes for concrete blocks used with a center to center spacing of 1.5m. As the LW enters this pre-driven recovery room there are notable responses and shifting ground stresses. This study was undertaken to measure the ground response using seven vibrating wire displacement transducers. These devices were used to monitor the convergence as the LW approached the recovery room. The methane concentration in the air ventilating the recovery room was also monitored. The correlation between convergence and gas liberation was then studied. The results show that the convergence varies from 0.1m to 0.25m along the length of the recovery room. Ventilating the recovery room becomes critical as methane is liberated from oil shale as the more plastic floor material is disrupted. Appropriate methods are employed to ventilate the recovery room.

Feb 23, 2014

By Gregg A. Swayre, Roger N. Clark, Stephen J. Sutley, Kathleen S. Smith

Imaging spectroscopy is a relatively new remote sensing tool that provides a rapid method to screen entire mining districts for potential sources of surface acid drainage. An imaging spectrometer known as the Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) measures light reflected from the surface in 224 spectral channels from 0.4 - 2.5 µm. Spectral data from this instrument were used to evaluate mine waste at the California Gulch Superfluid Site near Leadville, Colorado. Here, the process of pyrite oxidation at the surface produces acidic water that is gradually neutralized as it drains away from mine waste, depositing a central jarosite zone surrounded by a jarosite + goethite zone, in turn surrounded by a goethite zone with a discontinuous hematite rim zone. Leaching tests show that pH is most acidic in the jarosite and jarosite + goethite zones and is near-neutral in the goethite zone. Measurements indicate that metals leach from minerals and amorphous materials in the jarosite + goethite and jarosite zones at concentrations 10 - 50 times higher than from goethite zone minerals. Goethite zones that fully encircle mine waste may indicate some attenuation of leachate metals and thus reduced metal loading to streams. The potential for impact by acidic drainage is highest where streams intersect the jarosite and jarosite + goethite zones. In these areas, metal-rich acidic dace runoff may flow directly into streams. The U.S. Environmental Protection Agency estimates (U.S. EPA, 1998) that mineral maps made from AVIRIS data at Leadville have accelerated remediation efforts by two years and saved over $2 million in cleanup costs.

Jan 1, 2000

By Robert E. Ennis

The somewhat misnomered "continuous" face section is in most mines today still far from perfect continuity. Achieving uninterrupted flow of coal from the mining machine to the outside has been a long sought for goal. Clearly, the largest problem to be solved in continuous mining today is one of increasing the cutting time of the miner. Full machine utilization can never be achieved with the new high capacity miners, as long as their performance is tied to that of the shuttle car. Figure No. I illustrates the point at which shuttle car haulage distance determines unit productivity rather than the productive capacity of the miner. Continuous mining is never realized. A recent development has proven, however, that truly continuous mining and haulage is possible. The Bell & Zoller Coal Company working with the Research and Development Department of Hewitt-Robins Inc. developed and perfected a new mining system which offers advantages in terms of increased productivity at reduced mining costs and enhances the safety of personnel at the face. This new system involves the use of two pieces of equipment that form a unbroken link, at all times, between the mining machine and the mine belt haulage system. These pieces are a Mobile Bridge Conveyor, and an extensible panel conveyor. The following areas of discussion will be covered during the review of this development. I. The design and operating features of the new system. 2. Its application in underground mining 3. The performance of the system to date 4. Operation and maintenance cost considerations 5. Safety features of the system

Jan 1, 1965

By D. Brabec

One of the analytical problems in exploration geochemistry is the choice of a method of sample attack which would be rapid, simple and reliable in terms of precision and discrimination between different concentration levels of elements sought. The wet sample attacks currently used in analysis of silicate rocks vary from total decomposition to leaching by weak extractants. The total decomposition of such materials is usually achieved either by alkaline fusion or hydrofluoric acid attack. The first method requires the use of platinum vessels which is both expensive and slow for batch operation. The second type of attack is more widely applied in rock geochemistry1, but it is still relatively slow for exploration purposes and requires extra care (especially when hydrofluoric acid is used in mixture with perchloric acid). Considerable improvement in speed can be achieved by using the sample attacks which release only part of the metal present in a rock.2,4 One of such attacks is the leaching of pulverized rocks by hot aqua regia.3 Another technique widely used in geochemical prospecting involves fusion of the samples with potassium pyrosulfate (or bisulfate) followed by an acid leach of the malt .5 One of the advantages of these techniques is the use of glassware in decomposition stage which considerably increases the analytical productivity. It should be noted that partial chemical attacks tend to extract from a rock mainly the non-silicate metal which may give results more significant for exploration purposes than the analysis for total metal.

Jan 1, 1970

By Stephen E. Kesler

Carbonaceous sedimentary rocks are abundant in the upper part of the caldera or maar that hosts the Puebio Viejo Au-Ag district, and much of the Moore sulfide zone is in these rocks. These rocks are thinly layered and contain scattered plant remains and variable amounts of volcaniclastic debris and pyrite. The carbonaceous matter in the sediments yields no X-ray diffraction pattern and is not graphite. It has C/N ratios of 4 to 10, and &13C values of about -25 per mil, which indicate that it is dominantly of marine organic origin and partly degraded. Atomic S/C ratios in the unmineralized part of the carbonaceous rocks have a median of about 1.2, much higher than most similar unmineralized rocks, reflecting not only the abundance of pyrite in the sediments, but also the fact that the organic material contains several percent sulfur. Extracts from the organic material indicate that it is thermally mature and that it reacted with the hydrothermal solutions. Atomic S/C ratios in the mineralized carbonaceous rocks are generally higher than those in unmineralized carbonaceous rocks, ranging to values of 5 and more. These differences indicate that significant amounts of carbon were consumed by the reduction of sulfate and metal chloride complexes in the mineralizing fluids as they passed through the carbonaceous sediments. Direct reaction between organic material and ferrous chloride-bearing, acid-sulfate hydrothermal solutions probably caused continuous deposition of pyrite during this period. Intermittent deposition of gold from chloride complexes by the same reaction was probably facilitated by boiling or C02 effervescence.

Jan 1, 2013

Vancouver-based War Eagle Mining Co. is an advanced-stage Canadian junior mining company that is focused on becoming one of the world?s leading germanium producers. War Eagle?s primary focus is on the Tres Marias high-grade germanium mine near Chihuahua, Mexico. The Tres Marias Mine has high-grade zinc mineralization as well. War Eagle acquired the 28-km2 (17.4-sq mile) property in 2001 from Tombstone Exploration and is currently working to put the mine into production. Current exploration is focused on supporting a resource report and prefeasibility study that is expected to be completed in early 2008. War Eagle expects to have completed an estimated 80 underground diamond drill holes, 40 surface diamond drillholes, 31 percussion holes and 1,296 1.5-m (5-ft) channel samples. Eighty-seven additional exploration targets have been identified within the mining concession. Recent drill results have significantly expanded the known mineralized body at the Tres Marias Mine. The exploration and development program is expected to be completed during 2008. War Eagle owns both the drills currently in operation at Tres Marias. An advanced exploration and development program has confirmed historical grades and is producing encouraging new results from diamond and percussion drilling, channel sampling and high-resolution resistivity geophysics. Glenn R. O?Gorman, an independent geologist and consultant to War Eagle, conducted a study on the reporter. He stated that the Tres Marias concession area has the potential to host 5 to 10 Mt (5.5 to 11 million st) of minable ore.

Jan 1, 2008

By S. J. Aparo

Phosphate mining and beneficiation in the State of Florida are presently being carried on by 12 different mining companies with a total of 21 mining and flotation plant locations. Their combined production of both washer rock and flotation concentrate was approximately 28,000,000 long tons in 1968. This accounted for 70-72% of the total U. S. production and close to 30% of the world's output of this mineral. From this extensive activity in the Florida phosphate field, one basic flow sheet for beneficiation of the ore has developed over the years as the most commonly employed. In fact, all of these plants with the exception of two beneficiate Florida pebble phosphate using a basic operation as illustrated in Figure I. The two plants which differ from this general approach are not using raw matrix as feed. In one instance, +14 mesh pebble is ground in a rod mill to release free silica which is subsequently removed in a cationic froth flotation circuit using an amine acetate blend and kerosene. This technique generally results in a 4-7 BPL unit upgrading of the feed pebble. The other exception to the standard flow sheet illustrated in Figure I is an operation which is beneficiating tailing piles. In this case, the material is first subjected to cationic froth flotation in order to upgrade the feed to a point comparable to normal matrix. Thereafter, after, the phosphate is floated in an anionic rougher circuit followed by cationic flotation of the silica in a cleaner circuit.

Jan 1, 1969

By Scott A. Norby

Kennecott's Ray Mines Division (RMD) is located in central Arizona. The pit and silicate plants are located at Ray while the 27,500 tpd concentrating facilities are located at Hayden, approximately 20 miles away from the pit. Ore is delivered in 100 ton railroad cars, 60 cars per train via the Copper Basin Railroad. The side discharge cars are dumped into a 6,000 ton trackhopper. There are 6 Nico feeders, two per belt. Three 48" belts transport the -8" ore to three 7' standard (secondary) Nordberg crushers. Each crusher is preceded by a 6' x 12' Tyler double deck screen. The secondary crushers are open circuit. The -1/21t material from the screens is transported directly to the fine ore bin at the mill. The discharge from the crushers and the intermediate product -2 1/411 x +1/2" is conveyed to a surge bin. The tertiary crusher feeder belts discharge onto five 61 x 161 Tyler double deck screens, each followed by a 7' shorthead (tertiary) Nordberg crusher in closed circuit. The -1/2" product joins the -1/2" ore from the secondary crushers and both are conveyed along a 42", 4,230 foot long belt to the fine ore bin that feeds the grinding circuits. When hard ore is experienced at the concentrator the daily throughput decreases by up to 10%. This coupled with the fact that the ore is generally becoming harder with mine depth provided the incentive to improve the performance at the crushing plant.

Jan 1, 1986

By David R. Klug, Chris Gause, Troy L. Page

The Inter-Island Tunnel is one of two undersea tunnels which are part of the Boston Harbor Clean-Up Program. The tunnel is 7.7 km (25,160 ft) long, bored to a 4.3 m (14 ft) diameter in the Cambridge Argillite Formation and was finished to a 3.5 m (11.5 ft) diameter final concrete lining. The owner is the Massachusetts Water Resources Authority (MWRA) who is a regional authority responsible for overall design and construction. The tunnel's primary purpose is the transport of untreated effluent from Nut Island facility in Quincy, MA to the new treatment plant at Deer Island. Two sludge lines are installed for the transport of sludge from Deer Island to Nut Island. During construction the contractor encountered fault zones, fractured strata, and soft ground tunnel sections which liberated more ground water than was originally anticipated by the project designer. Ground water was controlled during mining and the placing of the final lining. The final lining of cast-in-place concrete had to be backfill grouted to cut off water inflows and provide contact for equal tunnel loading which is critical in long-term design. This paper deals with an engineered backfill grouting system which was the first of its type to be used in North America. It discusses the geological conditions encountered, the design criteria used in the evaluation process, and an indepth review of the various system components. It demonstrates how contractors can use knowledgeable and professional industry suppliers to solve difficult construction problems.

Jan 1, 1999