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By E. Gock

Based on the scientific investigations on mechanochemical synthesis of metal sulphides from metals or metal compounds and sulphur or sulphur compounds, the article describes the industrial production of nanoscale metal sulphides. Special operational conditions such as inert atmosphere, size and type of the grinding balls, grinding time and specific energy input are taken into consideration. A system configuration for the manufacturing of sulphides at a capacity of 100 kg/h is presented.

Jan 1, 2014

By Alejandro Uribe-Salas, Fabiola Nava-Alonso, Gloria Dávila-Pulido

This paper presents results of an experimental study performed on the role of calcium sulfate present in flotation water on sphalerite flotation in the Pb/Cu circuit (non Cu-activated sphalerite) and in the Zn circuit (Cu-activated sphalerite). In the Pb/Cu circuit calcium ions adsorb on the negatively-charged sphalerite favoring xanthate adsorption and therefore making sphalerite floatable; experimental measurements show sphalerite contact angle increases with calcium concentration while xanthate adsorption onto sphalerite increases with the increase of pH and calcium concentration. Gypsum (CaSO4·2H2O) eventually present due to calcium sulfate precipitation is not detrimental to flotation at this stage since it is negatively charged at pH 9 and therefore, does not adhere onto the surface of negatively-charged sphalerite. In the zinc circuit, Cu-activated sphalerite decreases its negative charge (or even becomes positively charged) and develops some hydrophobicity due to the polysulfide produced by Cu-activation. At this stage calcium ions do not interact with the mineral surface and therefore do not favor xanthate adsorption; nevertheless, precipitated gypsum particles do adhere onto the mineral surface, greatly affecting its floatability (e.g., contact angle). Addition of sodium carbonate to dissolve gypsum and to precipitate calcium as calcium carbonate, which disperses in the bulk of the suspension, effectively restores mineral hydrophobicity. SEM observations coupled with EDS analysis clearly illustrate and support the above sequence of events.

Jan 1, 2014

By Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

"There are a variety of methods suitable to analyse elemental and mineralogical contents of rock drill core samples. Current demands are on fast exploration and objective analysis of ore samples. This paper proposes a combination of Laser-Induced Fluorescence (LIF) and image processing, entitled LIF-imaging, as a potential method for automated mineral analysis of the drill core samples. It is shown that LIF-imaging can produce a mineral map of the fluorescent minerals existing on the surface of the drill core samples. The test cases are drill core samples from a Ni-Cu mine situated in Kevitsa, Finland. The main prerequisite of LIF-imaging technique is a reference data, linking colours to the minerals. This study describes the calibration of LIF-imaging technique using precise but slow Raman spectroscopy. Using regularized logistic regression, a model is obtained that classifies the minerals based on their emitted fluorescent colours in the digital images. The abundance of each mineral group is estimated by pixel counting. The results are compared with X-Ray Diffraction laboratory assays performed on the same samples. The results show that the interpretation of the fluorescent minerals through LIF images corresponds to the XRD results. Furthermore, the utilization of the logistic regression to interpret the existing fluorescent minerals greatly improves the technique."

Jan 1, 2014

The present work aimed to verify the possibility of using froth flotation to separate the constitu-ent minerals of an alaskite rock waste having as the main minerals quartz and feldspar. Three stages of tests have been carried through. In the first stage was used an amphoteric collector for flotation, diaminedioleate, at pH 2 and, after analyzing the final products, a very poor selectivity was ob-served. During the second stage of tests, different collectors that are normally used for feldspar flo-tation as amines, sulfonates and soybean oil were employed. Once more, it was not possible to reach reasonably selective results. In the third stage, a salt of etheramine was used for collecting the feldspar and hydrofluoric acid was utilized for controlling the pH. A simulation of three flotation steps (rougher, cleaner and recleaner) permitted to attain a good selectivity in the flotation process. A concentrate with a silica content of 96.6% was obtained. The low concentrate content of alkalis totalizing 0.52% and a feldspar recovery of 96.5% to the tailings, represented by the high content of Na, K, and Al2O3 in the tailings, demonstrated that the concentrate was made up mostly of quartz.

Jan 1, 2014

By John A. Herbst, Ming Song, Xiangjun Qiu

It has been known for sometime that as wear occurs in tumbling mills there is an associated change in mill throughput. These changes have traditionally been simplistically, attributed to “mill volume effects”. New high fidelity simulation tools (involving DEM, CFD and Breakage models) are now giving new “microscale” insights into the complex interactions that occur between evolving lifter/liner profiles and breakage. The study described here shows that these new tools can allow the design of wear part profiles which will maximize mill productivity over the entire life of a liner/lifter system.

Jan 1, 2003

By A. N. Zagorodnyaya, T. N. Bukurov, Z. S. Abisheva, A. S. Sharipova

"The paper describes the results of stripping of copper production dusts by leaching with aqueous soda, nitric acid solutions and recovery from solutions resulting in the production of lead sulphate, tribasic lead sulfate (TBLS), ammonium perrhenate, zinc, copper-cadmium cake.The combination of two stripping operations under chosen optimal conditions allows the recovery of 98% rhenium, 82% lead, 92 % copper, and 96% zinc and cadmium each. The major amount of rhenium (~ 80%) is recovered at the carbonization stage, and other metals - at the nitric acid leaching stage.Lead sulfate was precipitated by mixing solutions resulting from carbonization and leaching. Tribasic lead sulfate was produced by dissolving lead sulfate in sodium hydroxide solutions. Rhenium was recovered from mother liquor resulting from lead sulfate precipitation by liquid-liquid extraction and zinc was recovered from raffinates. Trialkylamine (TAA) was used as an extractant for rhenium recovery and di-2- ethylhexylphosphoric acid was used for zinc recovery. Optimal liquid-liquid extraction parameters have been defined allowing the recovery of 96% rhenium in crude ammonium perrhenate and 94% zinc in sulfuric acid solution. Based on the experimental data, the flowchart for dust processing to produce salable products - lead, rhenium, zinc salts has been suggested."

Jan 1, 2003

By Valentine Chanturiya, Irina Khabarova, Maria Ryazantseva, Igor Bunin

"XPS investigations of the influence of HPEMP - treatment duration on the surface composition for natural chalcopyrite and sphalerite are described. HPEMP is a video pulse with a nanosecond front lasting between 5 and 10 ns. The electrical field component can reach 30 kV, whereas pulses repetition frequency is 100 Hz. In general, the formation of metal-deficient surfaces, polysulphides or elemental sulphur and oxides/hydroxides, were determined during the treatment for both sulphides as well as the essential differences of the way of mineral surface transformation during the treatment. The chalcopyrite surface shows the formation of elemental sulphur under the HPEMP treatment at 103 pulses while appearance of unstable sulphite species was detected at the chalcopyrite surface within 5 seconds (0.5•103 pulses) under the same treatment conditions. The results indicate that the quantity of adsorbed water (at.%) is changed considerably during the HPEM - treatment depending on treatment duration for both minerals. The concentration of water onto the chalcopyrite surface decreased during 30 seconds (3•103 pulses) of the HPEMP - treatment and it rose after the treatment at 5•103 pulses. The inverse dependency was obtained for sphalerite surface. Single mineral flotation tests have shown the significant increasing of the minerals recovery."

Jan 1, 2014

By Sergey Romanenko, Tatyana Aleksandrova, Karen Arustamian

"Current status of question about grinding stage effect to electrochemistry parameters of operation preparation slurry before intermediate selective flotation was assessed in the present scientific work. Needs of more detail study chemical reactions in the slurry preparation and flotation processes were shown. The ores are polymetallic sulphide type and the one are most difficult for mineral processing. The methodology allows increase information base during floatation tests. Ionometric methods and elements of neural network have been used in the study of mineral processing questions.We have also identified the relationship between the received values of the electrochemical parameters and the technological results in selective flotation. The optimal values of the electrochemistry parameters in operation of the preparation slurry before selective flotation has been found. The main effect of using the proposed methodology is to obtain scientifically based solutions to improve the technology parameters of flotation polymetallic sulfide ores. Challenging issue of selectivity of sulphide-polymetallic ores will be considered using case study of sulphidepolymetallic ores. It was shown that several factors are formed in ore grinding: formation of hydroxyl oxides of iron compounds, copper cation leaching, metal-sulphide and metal-sulphite complexes formation. The chemistry was revealed for current processes in slurry preparation operation before selective flotation. Quantitative assessment of interrelations between electrochemical parameters of slurry and process performance was given with using electrochemical control methods. Neuron network-based model was estimated based on data array and was allowed to establish optimum electrochemical conditions of metal-sulphite complex formation to provide maximum efficiency of selective flotation.INTRODUCTIONPhysical and chemical processes that take place in ore grinding have a significant impact on flotation selectivity and can cause low selectivity of the flotation process. Today this issue is given much attention. In the paper [1] it is pointed out that sulphide oxidation products and slurry components, such as sulphide ions, metallic iron and its oxidation products, have effect on flotation performance. So, metallic iron has impact on metal-sulphite complex formation as a result of oxidation-reduction reactions as follows:"

Jan 1, 2018

By A. Makavetskas

"The purpose of the research is to study the mineralogical features of the structure of the wall accretion formed during melting on the working surface of the walls of metallurgical aggregates and adversely affect the stability of the lining of blast furnaces (BF). We presented the results of studies of the material composition of lining and wall accretion of the furnaces of blast furnaces of the metallurgical plant specializing in the smelting of ferromanganese, nodular and pig iron. It is established that the garnissage is an aggregate of layered texture, formed as a result of the crystallization of slag and metallic melts. Refractory calcium and magnesium silicates and aluminosilicates (minerals of the melilite group, leicite, olivine group minerals) and amorphous glassy oxide solid solutions of variable composition crystallize from the slag melts in the upper part of the hearth. In the slag matrix, inclusions of carbon (amorphous and graphite) and products of crystallization of metallic melts of alpha-iron, iron carbides and / or manganese are observed. Evidence of carbon evolution (in the form of graphite) is precisely in the crystallization of metal melts, there are significant differences in the structure of carbon in coke and in the garnissage. The conducted studies confirm that it is impossible to obtain reliable information on the material composition of new formations in the blast-furnace process without using a complex of modern methods of technological mineralogy.INTRODUCTION The formation of the wall accretion (garnissage) - a solid protective layer as a result of smelting products crystallization on the inner (working) surface of the liner. This is due to the design of blast furnaces with a high-efficiency heat sink using copper coolers and the use of carbon blocks with high thermal conductivity in the lining. The objective of the study was research of the material composition of the lining and wall accretion of the blast furnace hearth of one metallurgical plant that specialized in smelting ferromanganese, nodular and pig iron, to assess the effect of new formations for stability of the lining of blast furnaces (BF)."

Jan 1, 2018

By V. Sheikhzadeh, M. Saghaeian, R. Hejazi, M. Zare

High Pressure Grinding Roll (HPGR) plays a major role in increasing specific surface area of iron ore concentrate for producing pellet feed. HPGR grinding mechanism implies that material be compressed between the two rolls, therefore layer of material must be able to resist required pressure for achieving suitable grinding conditions. In this study for determining a simple relationship between material pressure resistance ability and HPGR main design parameters, piston press tests were performed on different iron ore concentrate samples along with HPGR Blaine increasing tests. Piston press tests results showed that by decreasing moisture content, material pressure resistance increased and in constant moisture content this parameter will change based on material specifications. HPGR Blaine increasing tests results showed that by decreasing moisture content, HPGR specific throughput and working gap increased and in constant moisture content this parameter will change based on material specifications. For all of the studied samples at worst condition, we got the results including: HPGR delta gap equal to zero, specific throughput lower than 200 ts/hm3.According to the tests results, HPGR Applicability Index (HAI) can be introduced at four different class types from 1 (weak) to 4 (excellent). This index determines achievable specific throughput and possibility of using HPGR according to material specifications, i.e. for HAI 1-4 the pressure resistance is <90, 90 to<125, 125 to <150 and = 150 bar, respectively. Similarly for HAI 1-4 specific throughput is <200, =200, =220 and =250, respectively. So based on design moisture content, if concentrate HAI is 3 or 4, HPGR is a correct choice. For HAI 2, HPGR can also be used. But for a material with HAI equal to 1, HPGR is not a good solution. As a result in order to apply HPGR for HAI 1, material condition such as moisture or slime content should be decreased.

Jan 1, 2018

By M. Rudolph, E. Schach, M. Buchmann, T. Leißner, N. Krupko, U. Peuker, M. Kern

"In mineral processing, density and magnetic susceptibility are two very fundamental properties. For the beneficiation of valuables to produce a saleable concentrate a detailed understanding of these properties is essential. Especially when it comes to the processing of cassiterite, which is the main mineral for tin production, they become highly prominent. Due to the chemically inert character of cassiterite towards most industrial applied leaching agents, density and magnetic separation processes are mainly applied for its beneficiation. To guarantee an optimized utilization of the different operations not only cassiterite but also the different gangue minerals have to be considered. In this study, a skarn ore is characterized by density and magnetic susceptibility. Therefore, the material was first split into different density classes by heavy liquid separation. The obtained classes were further separated by their susceptibility to finally obtain a density-susceptibility matrix. For this purpose, an isodynamic separator was used. A more detailed characterization of the materials is done via gas pycnometer, magnetic susceptibility balance and vibrating sample magnetometer to estimate the characteristics of density and susceptibility for the various classes. Further, the determination of the chemical assay and the mineral intergrowth by mineral liberation analysis is used to generate a three dimensional database for detailed characterization of the present ore. The objective of this study is to estimate potential material streams for a modular processing plant via characterization of the material for the entire deposit by the two afore mentioned characteristic properties. The established multidimensional data matrix, enables predictions for the separation properties of the material and contributes to the characterization of the deposit within the context of geometallurgy."

Jan 1, 2018

By X. W. Lv

The intelligent recognizing and processing system for sinter ore mineragraphy make a great convenience of recognition and measurement. Specially, it?s critical important for a successful intelligent system to extract the minerals? feature accurately and sufficiently. Reflection index, as the crucial feature of mineral, is calculated by the theoretical calculating model of index based on the principle of imaging color models. In gray histogram of minerals? micrograph, the peaks? positions represent the information about mineral categories and contents. The relationships of different minerals? peak-positions in curve of gray histogram were got by using the peak-find model of gray histogram and calculating model of reflection index. These two models which can be regard as the method of feature extraction for minerals? photomicrograph also lay a good foundation for the artificial intelligent system of recognition and processing in sinter ore.

Jan 1, 2014

By N. Vorob?ev-Desyatovskii

The process of gold(I) adsorption on activated carbon (AC) from aqueous Na[Au(CN)2] and the state of the adsorbed gold cyanide complex on the adsorbent surface was investigated by photometry, XPS, XANES methods. By DFT method, quantum-chemical calculations were performed of the gold cyanide species on activated carbon surface. It was established that the binding of gold(I) with the surface of carbon involved several simultaneous processes governing the selective adsorption of gold(I) from the cyanide solutions.

Sep 1, 2012

By B. McFadzean

Thiol collector mixtures are commonly used in the flotation of base metal sulfides and platinum-bearing ores. There are synergistic benefits claimed for these collector mixtures, with mixtures lowering total dosage requirements, improving coarse particle recovery and the rate of flotation. Some of the secondary collectors are known to have frothing effects. Therefore, a previous study aimed to decouple froth and pulp effects and considered only the bubble-particle attachments in the pulp. This was achieved through microflotation experiments, where various ratios of the ethyl and isobutyl chain lengths of xanthates, dithiocarbamates and dithiophosphates were used as collectors. Results from these experiments showed a marked increase in galena recovery using mixtures of xanthate with either dithiophosphate or dithiocarbamate. In the current study, the froth phase was introduced in the form of batch flotation studies to determine whether benefits noted during microflotation experiments would be carried through to a more realistic froth flotation scenario. The findings show that there was no significant difference in the flotation recovery between the best single collectors and mixtures of these collectors. In addition, single collectors that behaved poorly in microflotation experiments showed good flotation performance in the batch flotation experiments. The differences between the microflotation results and the batch flotation results are attributed to differences in particle froth stabilizing properties and/or differences in energy input between the microflotation and batch flotation cells. In addition, galena and pyrite showed marked differences in frothing effects and in their preferences for collector type. Keywords: froth flotation, collector mixtures, sulphide minerals

Sep 1, 2012

By P. Chris Pistorius, Johannes Sono, Rossouw Sono, J. J. Kobus

Different coal properties are important in SL/RN (coal-based rotary kiln) direct reduction of iron ore, and in electrical smelting of prereduced iron ore. These differences were highlighted when a plant which processes titaniferous magnetite had to change to different coal types after decades of operation. Laboratory simulation was used to evaluate two candidate coals, which were similar in volatile content and rank, but differed in reactive maceral content. Direct reduction was evaluated by isothermal experiments using a packed bed of ore and coal, measuring the off-gas composition to determine reaction rates and departure from equilibrium. These indicated reduction to be under mixed control, and quite sensitive to temperature (confirming that the coal reactivity is of importance). An aspect of electrical smelting was assessed by determining dissolution rates of the coal in molten iron at 1550°C. Dissolution rates did correlate with differences in coal structure, as determined by X-ray diffraction, with the more ordered ("more crystalline") coal dissolving faster. The conclusion is that the coal which is more reactive during direct reduction is less reactive during dissolution. However, it is concluded that controlling the temperature during direct reduction offers a feasible method to reconcile the two process steps.

Jan 1, 2003

By M. I. Panayotova

Some of effluents released by copper smelting plants are highly acidic (pH = 0~1) and contain arsenic and copper in relatively high concentrations (10~20 g/L). Usually arsenic is removed by precipitation with different reagents, such as lime, iron salts, calcium salts, aluminium salts, etc. Precipitates (often voluminous) that require further handling are formed and copper and other valuable components are lost. A method is presented for copper and arsenic extraction from acidic effluents. Effluents are treated in specially designed closed electrochemical cell without chemicals? addition. Gases formed are collected and treated for decomposing the eventual traces of As-bearing compounds and ensuring the environment protection. Initially copper of grade of 85 % is electro-won. Further about half of the initially available arsenic is separated as low-soluble, low volume mixture of intermetallic compounds, oxides and some elemental arsenic. At the next stage the main part of the left arsenic is immobilized as low soluble stable compound. Arsenic content in the treated acid is in the range 0.20~0.25 g/L. Acidity of treated effluent after first two stages remains practically unchanged and the solution can be re-used. Physicochemical and electrochemical processes, governing copper and arsenic removal, are discussed.

Jan 1, 2014

By Yuexin Han, Wenbo Li, Yan Shan, Yanjun Li, Shumin Zhang

"With the accelerating pace of resource extraction, the quality of resources is decreasing, and the old tailing dams which have served for several decades have become the focus of attention. The secondary recovery of valuable metals in the tailings is an important aspect of the comprehensive utilization of tailings. The average iron content of iron tailing is 8%-12% in China. The research aimed at exploring the low-cost and efficient technical route to recycle eastern tailings of Anshan iron mining area. The purpose of the research is to scientifically find the rational conditions of magnetizing roasting and to provide an increase in recovery and quality of concentrates. The eastern tailings of Anshan mining area belong to high silicon bearing iron tailings, iron mainly exists in form of hematite-limonite with an iron grade of 10.60%, the main component of gangue is SiO2 with a grade of 76.22%. In order to reduce the influence of the tailings on the environment, fluidized magnetizing roasting and low intensity magnetic separation for the eastern tailings of Anshan mining area were carried out to improve the utilization of the tailings. The results indicated that an iron concentrate with an iron grade of 65.30% and a recovery of 85.85% could be obtained under the conditions of gas flow rate 8 m3/h, H2 concentration 50%, fluidized magnetizing roasting temperature at 600? for 20s. Phase analysis, magnetism analysis and XRD analysis on roasted materials indicated that hematite-limonite could be transformed to magnetite during the fluidized roasting, then the effective separation of iron and gangues could be made easily by the weak magnetic separation. INTRODUCTION It is universally acknowledged that the grade of iron ore in China is low, the output rate of iron ore tailings is high, usually more than 60%. At present, the comprehensive utilization rate of iron ore tailings is low in China. Generally, the iron ore tailings are stockpiled in the tailings dam. The tailing dams not only occupy a lot of land, but also takes a lot of money to construct and maintain. In addition, the noxious substances in the tailings, such as residual flotation agents and heavy metals, have a severe impact on the ecological environment. There is little doubt that tailing dams have a visual impact on the environment due to their regular geometric shape. Iron tailings can be treated as compound mineral, which is an important component of comprehensive utilization of mineral resources, and is an has been widely concerned. Lots of scholars have done a large amount of research work on a large number of iron ore tailings. Since the iron mineral crystal grain size is fine and the iron grade is low, the iron tailings have failed to achieve good selection criteria."

Jan 1, 2018

By S. Kelebek, A. Khan, J. Caceres, Beckett. D.

"Pyrrhotite in nickel-copper sulphide ores is nickeliferrous and intimately associated with pentlandite. Due to its low nickel content, pyrrhotite rejection is an important step in processing of these ores. In our laboratory, various reagents were investigated for their effect on pyrrhotite depression. Among these, a combined use of triethylenetetramine and sodium metabisulphite was found highly promising.The work described in this paper has two parts. The firs part is a summary of results obtained on process samples from the pyrrhotite rejection circuit at Falconbridge’s Strathcona Mill. The second part involves simulation of the circuit performance based on the reagent conditions used in the experimental work and the concept of split factors.Two sets of reagent conditions were evaluated. The first one involved baseline conditions, simulating the current reagent performance. The second one simulated the impact these new reagents can have on the circuit performance.The simulation results obtained under baseline conditions indicated a good agreement with the current circuit performance. The simulation results suggest that at practically the same pentlandite recovery and tailing grades, the circuit concentrate nickel grade can be doubled through effective pyrrhotite rejection by these new reagents."

Jan 1, 2003

By I. Zh. Bunin, G. K. Khachatryan, N. E. Anashkina

For optimization of diamond processing technology the influence of nanosecond high voltage pulses on mechanical and technological properties of diamond crystals and kimberlite rock-forming minerals (calcite, olivine, serpentine) was investigated. Using methods of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and mikrohardness measurement the changes of structural, physic-chemical surface properties, and microhardness of minerals as the result of impacts, was studied. Non-thermal impacts caused a decrease of kimberlite rock-forming minerals microhardness in general to 40-66% as the result of surface microstructure destruction which is caused by formation of micro cracks, traces of surface breakdown and other defects. At the same time, the pulse energy impact on natural diamonds led to formation of B2 type crystal lattice microsift defects, elevated concentration of which increases the hardness properties of crystals. The obtained result indicates possibility of applying pulsed energy effects to improve the softening efficiency of diamond-bearing kimberlites rock-forming minerals without damaging the diamond crystals and ensuring their preservation by the subsequent grinding of ores. By IR and X-ray photoelectron spectroscopy revealed that processing by hight voltage pulses causes a change of natural and synthetic diamonds surface functional cover composition. Short-term exposure (~ 10 - 30) leads to detachment and partial destruction of secondary phases mineral films on the surface of natural technical diamonds, increasing floatability and hydrophobicity of crystals. However, with increasing duration of treatment (~ 30 - 150) occurs surface hydroxylation (found by XPS for synthetic diamonds), as a result of diamond surface layer oxidation. The effect of increasing the natural diamonds flotation activity by 14% (from 47% to 61%) was experimentally established as a result of processing diamond crystals with nanosecond pulses (~ 10-50 sec), which indicates the principal possibility of using pulsed energy impacts to intensify the diamond flotation during processing diamond-bearing kimberlites.

Jan 1, 2018

By Ljudmil S. Grigorov, Eric Forssberg, Hanumantha Rao Kota, Robert J. Pugh, Lidia B. Alexandrova

"We have used the microscopic thin balance developed by Scheludko at al. (1970) technique to study the stability and interactions within the thin film between the silica surface and air bubble with (i) a long chain C10 amine and (ii) a cationic/anionic surfactant systems consisting of mixtures of a long straight C10 chain amine with long straight chain C8, C10 and C12 sulfonates. It was found that the mixed surfactants caused lower contact angles, lower rates of the thin aqueous film rupture and longer film lifetime, compared to the pure amine system.This behavior was explained by the initial strong adsorption of positively charged interfacial complexes from the mixed surfactant system at the air/solution interface followed by adsorption at the silica interface. It was also shown that the chain length compatibility between the anionic and cationic surfactants controls the strength of the interfacial complex, determining an inhibition in the thin film rupture and dewetting of the film. The rupture mechanism was explained by an earlier established heterocoagulation mechanism between the positively charged air/solution interface and the solution/silica interface which remained negatively charged. The formation of the interfacial complex at the air/solution interface was confirmed by using surface tension data."

Jan 1, 2003