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By George A. Komadina

Pima Mining Company has recently completed their expansion tripling the plant capacity to 18,000 tons per day and now is in the process off expanding to 30,000 tons per day with completion scheduled for the summer of 1967. This paper briefly discusses the additions to the mining department and support areas with a more detailed report on the complete new crushing plant and additions to the concentrator. The crushing plant includes a 54-inch gyratory crusher, three 7-foot standard and seven 7-foot short head crushers along with necessary screens, feeders, and conveyor belts to produce a minus 1/2-inch rod mill feed. The concentrator consists of ten milling sections, each containing one 10-foot by 16-foot rod and two 10.5-foot by 13-foot ball mills, classification is done with cyclones. Pulp from each section is floated in 50 cells of 66-inch Fagergren flotation machines to produce a rougher concentrate which is cleaned in six stages of Denver cleaners to produce a final concentrate The various mill products are thickened with disposal made in conventional manner. Plant instrumentation is discussed in the paper.

Jan 1, 1967

By J. A. Lepinski

The FASTMETSM Process is a coal-based process for converting iron oxide fines into metallic iron. The end product, direct reduced iron (DRI) is used as a low residual charge material in electric arc furnace steelmaking. This paper describes the FASTMET Process and its potential application in the United States. Operating results from a 175 kg/h process simulator are presented. Characteristics of the end product are discussed. Process economics are reviewed along with plans for scaling-up the process to full commercial size.

Jan 1, 1993

By Dan Wang, Qiuju Li, Xiao Guo

The chemical states and ions interaction were significant interest to understanding columbite mineral/acid solution interface dissolution and reaction. The present research work was focus to explore the specific cations ( Nb5+, Fe2+, Fe3+) distribution near the ferrocolumbite mineral/acid solution interface, and determine these cations leaching sequence in sulfuric acid solution. X-ray photoelectron spectroscopy had the potential to provide detailed dissolution information by resolving chemical state and ion distribution of ferrocolumbite during sulfuric acid leaching process. The binding energy decreased in sequence as Nb5+- O < Fe2+- O < Fe3+- O, and increased in sequence as Fe3+- SO4 < Fe2+- SO4 < Nb5+- SO4 which revealed Nb in ferrocolumbite mineral more easily leached comparing to Fe. The ratio of Fe2+- O/Fe3+-O on leaching residue decreased, and Fe2+- SO4/Fe3+-SO4 ratio increased as sulfuric acid contraction increasing suggested that the Fe2+ oxidized to Fe3+ and released Nb from mineral and dissolved into leaching solution. The ratio of Nb/Fe was lower 0.07 with sulfuric acid contraction increasing which meant Nb dissolution promoted by oxidation of iron. The dissolution mechanism of Fe element in ferrocolumbite mineral was Fe2+- O broken and generated Fe2+. Fe2+ was oxidized to Fe3+ in concentrated sulfuric acid leaching solution. The dissolution mechanism of Nb in ferrocolumbite was that Nb5+- O was directly digested by H+, and the released Nb5+ complex with SO4 2− ion formed cation − anion pairs. The coordination of formation Nb5+- SO4 pairs and oxidation Fe2+ in mineral could promote ferrocolumbite dissolution.

Aug 5, 2023

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) ammines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Nov 1, 2011

Recent accelerated exploration efforts in southwest China have progressively quantified the vast phosphate resources in the Yunnan Province. To date, according to Chinese geologists, potential reserves in the province may be on the order of 4 Gt, which would equal the entire US reserve base. Development of this vast reserve is underway at two sites located 60-70 km southwest of Kunming, the provincial capital of Yunnan. The first, the Kunyang open-pit phosphate mine, produces an estimated 1.5 Mt/a of 22-30% P20,5. The other project located north of Kunyang is the Haikou mine, which the Chinese consider a possible 2.0-Mt/a operation. Because average ore grades run 3% less than those of Kunyang, beneficiation will be necessary. While the latter project has been initiated on a small scale, it is basically still on the drawing board. Brown and Root and the US Bureau of Mines are assisting on the project. Both operations are under the direction a regional administration which reports to the Ministry of Chemical Industries in Beijing. Combined production from both mines could represent some 70% of China&apos;s future productive capacity. Ore reserves in the region are estimated at 400 Mt by local officials. Geology of the District The phosphates are considered Cambrian in age and rest on a Precambrian dolomite. The Indian Ocean, Chinese geologists say, may have been the original source. The line of deposition stretches on a trend from Vietnam in the southwest, through Yunnan, into Sichuan Province to the northeast. Because the area is considered very stable from a geologic viewpoint, large quantities of phosphate have been deposited and large outcrops are known to occur everywhere in the province, according to Chinese sources. The Kunyang and Haikou ore bodies are thought to be two wings of an anticline with the former the southern portion, and the latter the northern portion. Each ore body strikes on an east-west axis. While there are many localized phosphate operations throughout the province, the Kunyang mine is the premium producer. Kunyang&apos;s Mining Development The Kunyang open-pit mine was opened in 1966. During the early years, operations were considered somewhat disorganized. Systematic mine planning and normal operations were not initiated until just two years ago, according to mine management. In 1979, Kunyang finally reached its design capacity of 1.5 Mt/a. The ore body consists of two phosphate beds separated by a band of shale. The top layer of phosphate varies from 4 to 8 m, averaging 6 m. The middle shale layer is 2 in. The third layer, which is not as rich as the top, is approximately 4 m. To further complicate matters, the ore dips 15° to the south over a strike length that is currently undefined, but believed to be

Jan 3, 1980

By Hun-Joon Sohn

Chemical metathesis and electrochemical reductive conversion of chalcopyrite in the presence of cupric ions were studied in sulfuric acid solutions for temperatures up to 90°C. The process results in the displacement of iron in the chalcopyrite lattice by copper ions with rejection of ferrous ions to the aqueous phase. The rate of reaction was found to be very slow, requiring subsieve-sized particles for extensive reaction to occur. The reaction was insensitive to copper ion concentration. Stirred ball milling of chalcopyrite introduces lattice strain. The reaction rate with strained particles was markedly higher than with annealed chalcopyrite. The reaction rate was found to be diffusion-limited, showing two distinct reaction stages corresponding to the formation of CuS (covellite) followed by Cu1.8S (digenite). The experimental activation energy for the first stage was 102 J (24.4 kcal) and the second stage 123 3 (29.4 -kcal) per mole. The rate-controlling process is diffusion of lattice ions, probably iron. The enhanced rate after milling is attributed to a recrystallization process which provides new paths for diffusion along dislocations and grain boundaries.

Jan 1, 1984

By Fiona M. Doyle Garner

Hydrolytic stripping is the process whereby metal ions in a loaded solvent extractant are hydrolyzed by water, typically at 130°-200°C. Equilibrium hydrolytic stripping tests were done on Versatic 10 solutions of various metals, singly and in mixtures. Single solutions of Fe, Xi, Cu, Mg, and tin precipitated aFe2O3, Ni(OH)2, Cu2O, Mg(OH) 2 and ?Mn203 respectively during hydrolytic stripping. Several mixtures containing iron precipitated magnetic spinel ferrites, MFe20k. No other combinations formed mixed oxides. It is proposed that the mechanisms for hydrolysis and precipitation of iron in loaded Versa- tic solutions are similar to those for iron hydrolysis in aqueous solutions. Infrared spec- troscopy and thin-layer chromatography of mixed iron-nickel Versatic solutions indicated that mixed Fe-Ni carboxylate complexes are present. Magnetic interactions between mixed complexes are thought to be responsible for the homogeneous nucleation of magnetic mixed oxides in preference to single oxides.

Jan 1, 1984

By Simón Díaz-Quezada, HUMBERTO ESTAY

The heap leaching process has been widely used for recovering different metals since its first application at the end of the 1960s. In Chile, copper production via heap leaching has accounted for between 30 and 40% of annual copper production over the past 10 years. This level of production has been achieved through and supported by the use of a mathematical relation, known as the leaching ratio (LR) or irrigation ratio (IR), which relates operational parameters with metal extraction in a heap leaching operation. This ratio has been used to develop leaching column tests, to scale up results from the laboratory to industrial operations, to design new heap leaching plants, and in metallurgical control and production estimation. In spite of the widespread industrial use of this relation, few scientific studies mention it. This is due to its simplicity and basic theoretical foundations. This disparity between industrial practice and scientific research could lead to operational decisions which lack substantial theoretical support, and to scientific studies which have limited industrial impact. Against this background, several questions arise about the use of the LR: What are the constraints on the use of the LR? Are there practical advantages with respect to reported kinetic models? What is the main reason that industry prefers the use of the LR over kinetic models, which enjoy greater theoretical support? In order to guide its future use, this paper describes the leaching ratio and its current uses and limitations, through a literature review and case studies.

May 2, 2020

By Verya Nasri, Heather M. Ivory, Kevin Clarke, Eric Cole

Development of the New York City Water Supply System The New York City water supply system serves a population of almost nine million, including residents in neighboring counties. Peak day demands on the system are currently running at about 70 m3/sec (about 1,600 mgd), which is significantly lower than in the 1990s. This trend of reducing demands over the past 25 years, which has been experienced in other major urban centers in the US, is mainly the result of conservation measures and increased cost consciousness on the part of water users. In the long term, demands are expected to once again follow an increasing trend with population growth, so that by the end of the planning horizon of these studies, the year2045, the peak day demand is expected to increase to about 85 m3/sec (2,000 mgd).The system is served largely by surface water sources, regulated by a system of 19reservoirs and three controlled lakes, which are connected to the City by a series of aqueducts, the longest of which is about 87 km (54 miles). The total storage in the sys-tem amounts to about 560 billion gallons, providing a system firm yield of about1300 mgd. The Delaware system provides about 50% of the City’s water, the Catskill about 40%, with the remaining 10% provided by the Croton. The system as a whole, which is shown on Figure 1, has been built up over the past 150 years, and is truly a marvel of engineering. The Catskill and Delaware aqueducts both discharge into Kensico Reservoir, which is a daily balancing reservoir located in Westchester County about 24 km(15 miles) north of the New York City line. The two aqueducts extend south for a further 14 miles to combine again at Hillview Reservoir in the Bronx, which provides hourly balancing storage for New York City system. The Croton aqueduct runs nearby as shown on Figure 2, but does not connect into the two reservoirs. From Hillview Reservoir the water is supplied to the city via three main distribution tunnels, known as City Tunnels 1, 2, and 3. City Tunnel No.1 was developed in the 1920s as part of the Catskill system. City Tunnel No. 2 followed in the 1960s as part of the Delaware system. City Tunnel No. 3 (CT3) is partly under construction and partly in operation, and is being implemented to permit the other distribution tunnels to be taken out of operation for the first time for inspection and maintenance. Presently CT3 is supplied with water from Hillview Reservoir via a large underground valve chamber, the Van

Jan 1, 2007

By Edward A. Vitunac

The emerging importance of pneumatic conveying systems for bulk materials is becoming recognized by more persons responsible for materials management as consultants, at the corporate level and at the plant level. They have learned that the economic advantages of a pneumatic system are frequently decisive when compared to alternate methods. Included in these advantages are relative simplicity, ease of installation, flexibility, ease of maintenance, cleanliness, safety and ease of automation to the degree desired. In general, installed costs favor a pneumatic system when compared to competing mechanical systems if the transporting distances are long or to and from many points. In addition, supplemental use such as cooling, heating, or drying may supply the incremental value required to justify its selection. (1). The main disadvantages of a pneumatic system is the greater horsepower required per unit weight of material conveyed and material limits in abrasiveness and density. In addition, there is a tendency to increase material breakage at changes of direction and at any obstruction such as the imperfect butting of one, piece of pipe to another in the conveying line. Classification of the material at the discharge may also cause problems in dusting and segregation. Materials weighing less than 4 pounds per cubic foot tend to cause feeding and collecting problems although they can be conveyed easily. Material between 4 and 20 pounds per cubic foot can be handled with less problems but flow rate is hard to predict. The 20 to 60 pounds per cubic foot range offers best results; whereas, over 60 pounds per cubic foot, materials tend to drop out of the air stream and settle in the pipe line unless careful provisions are made to prevent it. (2).

Jan 1, 1967

By Wei Victor Liu, Na Zhang, Chengkai Fan, Bei Jiang

The truck haulage data from open-pit mine sites are usually massive and multidimensional with multi-peak Gaussian distributions. Artificial neural networks (ANNs) are well-known machine learning algorithms to handle massive and multidimensional data for building models. Moreover, Gaussian mixture modeling (GMM) is a suitable option for processing the data under multi-peak Gaussian distributions and improving model accuracy. For the first time, this study used a back propagation neural network (BPNN), an extreme learning machine (ELM), and a Bayesian regularized neural network (BRNN) coupled with GMM to deal with the complex truck haulage data and build three weighted ensemble models (WE-BPNN, WE-ELM, and WE-BRNN models) to predict truck productivity at mine sites. Decision tree (DT), random forest (RF), gradient boosting machine (GBM), and extreme gradient boosting (XGBoost) were used to build models to be compared with the weighted ensemble models. The results showed that the WE-BRNN had a higher accuracy than the WE-BPNN and WE-ELM models. The proposed weighted ensemble models performed better than the benchmark models in predicting truck productivity, indicating that a weighted ensemble approach based on the GMM analysis significantly improved the model accuracy. Based on the relative importance analysis, haul distance was the most crucial input variable for predicting truck productivity. This study provides a new approach to predicting truck productivity, which will help mining companies make sound budget decisions and improve mine planning.

Mar 2, 2023

"Controlling dust generation and keeping it below permissible limits at the working face of a room and pillar mine is a challenge for mine operators. With the recent changes in the respirable-dust regulation, it has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the National Institute for Occupational Safety and Health (NIOSH) stated that a flooded-bed scrubber, under its optimum condition, can achieve cleaning efficiencies between 58 and 90 percent. The performance of such a system can be maintenance intensive. Other industries face similar dust control issues. The University of Kentucky partnered with Toyota Motor Manufacturing for the development of a novel wet scrubber for capturing paint overspray, with capture efficiencies in excess of 98 percent and minimal maintenance. The aim of this study is to assess the ability of this novel wet scrubber to capture respirable dust in an underground coal mine. This paper presents the conceptual design and the computational fluid dynamics (CFD) modeling of this novel wet scrubber. It discusses the results of the CFD simulation performed on the novel wet dust scrubber. INTRODUCTION Dust generation from underground coal mining is an inescapable phenomenon. No matter the practices employed, it inevitably occurs. Elevated concentrations of coal dust are potential health and safety hazards. Although dust in an underground coal mine cannot be completely avoided, its influence can be mitigated through good engineering practices. The effect of dust on the health of mining personnel has had a significant impact. The prolonged exposure of airborne respirable dust (< 5 µm) can cause coal workers’ pneumoconiosis (CWP), silicosis, emphysema, and chronic bronchitis, collectively known as black lung (U.S. Department of Labor, 2014). According to the National Institute for Occupational Safety and Health, black lung has killed more than 10,000 miners between 1995 and 2004 (NIOSH, 2008). In addition to being a health issue, coal dust is also a safety issue to the underground coal miners. The generated dust, if not captured, is dispersed into the mine air through the ventilating air and deposited downwind on the return entries’ surfaces. In the event of a methane explosion, the coal dust, if insufficiently diluted with rock dust, triggers a coal dust explosion which is much more severe than a methane explosion and causes more damage (Kenneth et al, 2006). The Jim Walters No. 5 Mine and the Upper Big Branch Mine disasters which together killed 42 people and resulted in damage worth millions of dollars in property are the examples of coal dust explosions (U.S. Department of Labor, 2001 & 2010)."

Jan 1, 2016

By R. L. Grayson

A goal programming-based worker scheduling model has been incorporated in the Mine Management Support System (MMSS) for assigning workers to prioritized jobs on a shift basis. In the model the accomplishment of each regular and non-regular job is a goal. The objective is minimization of the deviations away from the goals. A number of coefficients are used as premultipliers of the decision variables in order to address practical considerations associated with the utilization of workers and the requirements of jobs. Some of these premultipliers will be updated expertly within MMSS, timely updating the statuses of the dynamic parameters.

Jan 1, 1991

Worldwide minerals exploration slipped in 1992 from 1991 levels. Although industrial production figures showed the US economy emerging from recession in early 1992, it was not until February 1993 that the lagging indicator of unemployment dropped to 7%. Most other industrialized countries are still in recession. Preliminary data for 1992 showed industrial production dropping in Japan (5%), Germany (1.4%), the United Kingdom (0.5%) and France (1.4%). The slowdown in industrial production led to reduced mineral demand. This resulted in lean cash flows from mining operations, which squeezed exploration funding. Although mineral prices were steady during most of 1992, some mineral commodity prices began falling in late 1992 and early this year. Exploration 1991-1992 According to Metals Economics Group (MEG), planned 1992 exploration expenditures were down by about 5%. Geographically, the leading exploration target was the United States with 21 % of the expenditures, followed by Australia (19%), Canada (18%), Latin America (15%), South Africa (9%) and the western Pacific (7.5%). The remaining 10% was split between Europe and Africa. There were absolute increases in exploration expenditures in the United States and Latin America. Latin America showed the largest increase. The change in the Mexican mining law allowing foreign ownership of mines should result in the inflow of direct foreign investment in Mexico&apos;s mining industry.

Jan 1, 1993

By Nicholas C. Lias

Quartz crystals are the raw material from which are made the crystal units utilized in filters and oscillators so vital to the performance of all long distance communications systems. These devices act as the heart of equipment that permits a single telephone cable to carry hundreds of conversations simultaneously. Quartz crystals are of value in communications because of this piezoelectric nature, that is when an electric signal is applied to the quartz, there is a resulting mechanical motion and conversely, a mechanical stress results in an electrical output signal. A plate cut from a quartz crystal will oscillate at some specific frequency, which is determined by the physical dimension of the plate. During the early stages of telephony, all quartz plates were cut from natural quartz, which was imported mainly from Brazil. Since the source of this important raw material was based upon a foreign supply which is located at a great distance from the user and could be vulnerable in time of a national emergent, it became necessary to maintain a large inventory of this strategic material. Also due to the considerable cost of natural crystals of a size and quality suitable for Bell System use, an investigation was made by Bell Laboratories into the possibility of developing a substitute material. The effort was successful and led to a joint development program between Bell Laboratories and Western Electric. This program brought about the design of manufacturing facilities capable of producing large quantities of cultured quartz at Western&apos;s Merrimack Valley Works, No. Andover, Massachusetts.

Jan 1, 1973

By K. E. Burgher

Since World War II, the need for the use of explosives in construction, mining, and quarrying near congested urban areas has increased dramatically. Often times a coal mine, once isolated from a city, finds itself surrounded by residential and commercial structures. The United States Bureau of Mines and others have researched blast design to a point where ground vibration and airblast damage can be avoided. A problem still exists, however. It is the fact that people often react to only the loud noise associated with a blast although it may not cause damage. Most often it is the concussion of a blast, less than 20 hertz and inaudible, that produces damage. Public fear from the "startle" and "fright" of loud blast noise greater than 20 hertz leads to the complaints which are generally unfounded. See Thackray, Touchstone, and Baily (1975) for a further discussion of the startle effects of loud sudden noises. When blasts are designed in accordance with U.S.B.M. specifications, management generally has little to worry about with respect to damage claims. Complaints, however, still arise when the noise is accentuated from the blast. It is meteorological conditions which dictate how the sound levels will propagate. Some mines use small pilot test shots (generally one-two lbs) to determine when atmospheric conditions favor sound travel.

Jan 1, 1987

By G. E. McClelland

Introduction Many discoveries have been made during the-past decade of low grade gold-silver deposits in the western US. This has stimulated development of low cost cyanidation procedures for precious metal extraction. Heap leach cyanidation techniques possess considerable potential for application to these low grade ores, small ore bodies, mine strip waste, and tailing materials where fine grinding is not necessary for good extraction. For heap leaching to be successful, these resources must have good permeability to achieve uniform distribution of the cyanide solution throughout the heaps. Some of the most difficult of the gold and silver ores to treat successfully by heap leaching are those containing excessive amounts of clays, or fines generated by crushing. Presence of excessive amounts of slimes, -50 µm (-270 mesh), in the heap leach feed will slow percolation, cause channeling, or produce dormant or unleached areas within the heap. This may result in unreasonably long leaching periods and poor extractions. In extreme cases, the clays or slimes can completely seal the ore heap. This causes the leach solution to run off the sides of the heap rather than penetrate the ore bed. The problem of heap leaching ores with fines can be aggravated while preparing ore heaps because of the natural sorting of coarse and fine material that occurs. This phenomenon results in concentration or ore fines in the center of individual ore piles and concentration of larger rock fragments of the lower slopes and base of the pile. When the individual piles within the heap are leveled off for the installation of the sprinkling system, additional segregation occurs as the fines sift through the coarser ore particles. This results in localized areas or zones with marked differences in permeability. Consequently, the leach solutions follow the course of least resistance. They percolate down through the coarse ore regions and bypass or barely wet areas that contain large amounts of fines or slimes. Effective use of marginal gold and silver resources by heap leaching required development of new methods to achieve more uniform size distribution when preparing ore heaps and better slime control during leaching. Early methods Agglomeration and balling of crushed ore to produce a porous and more uniform feed material for heap leaching is a viable method for treating clayey ores. Researchers from the US Bureau of Mines in Reno, NV began agglomeration pretreatment research in the mid-1970s for applications to and exploitation of these poor percolating feed materials. Little attention had been given to such methods before the Bureau&apos;s research. In 1905, T. C. Scrutton developed a unique technique for obtaining rapid vat leaching of a clayey ore where the gold was finely disseminated. His technique consisted of rolling the ore down a chute inclined at 60° to form agglomerates or balls readily permeable by the cyanide solution. However, these agglomerates lacked rigidity. And, to ensure good percolation leaching and washing, they could not be bedded in layers more than 1 m (3 ft) deep. If this depth was exceeded, it is difficult to obtain uniform leaching and washing. This results in reduced gold recovery. Shepard and others in 1937 studied the addition of lime and carbon dioxide or calcium carbonate to gold-bearing tailings to form agglomerates suitable for vat leaching. Satisfactory percolation flow rates were achieved in 90 g (3 oz) scale experiments, but the reagent requirements were cost prohibitive. Agglomeration and pelletizing has been used in other segments of the mineral industry. This technique was first used successfully around 1911 for pelletizing iron ores. Since then, agglomeration

Jan 7, 1986

By Jürgen F. Brune, SAMUEL A. LOLON, ADITYA JUGANDA, Gregory E. Bogin Jr

Historically, there have been many occurrences ofmine fires and explosions recorded in the United States and other countries that have demonstrated the existence of explosivemethane–airmixtures, herein referred to as explosive gas zones (EGZs). The risk of mine explosions can increase if the EGZs migrate out from the gob into the surrounding mine entries. Fluctuating barometric pressure is the common cause for EGZs outflowing or outgassing from the gob. Numerical analysis using a 3D computational fluid dynamics method was developed to fully understand the outgassing phenomenon. A number of simulations using various magnitudes and periods of barometric pressure changes indicated that the EGZ outgassing potentially occurs due to lags in pressure, which are strongly influenced by mine conditions and ventilation systems. An early warning system with a real-time pressure monitoring and the application of gob ventilation boreholes are recommended to detect and mitigate explosion hazards from gob outgassing.

Aug 24, 2020

By H. B. Oblad

The WEMCO® SmartCell™ flotation machine is a continuously-stirred tank reactor in which solids are suspended in water and are contacted with air. The reaction is particle flotation resulting in the separation of valuable material from gangue. The effects of several operating variables on the flows of water and air and on motor power were measured. A miniature magnetic flowmeter was installed in the draft tube that allowed measurement of the water flows into the rotor. This work has led to a better understanding of machine function which will lead to improved performance and better operation. General equations for optimization, design, and scale-up were inferred.

Jan 1, 2002

By Robert A. Westman

The INRED process has been developed step by step by Boliden since 1972 at MEFOS, the Foundation for Metallurgical Research, at Lulea in Sweden. The demonstration - plant is number five in this series. The purpose of this plant, which has a nominal capacity of 60,000 tonnes per year of hot metal is to: 1) prove the process on a sufficiently large scale to provide the basis for construction of production plants, 2) test various kinds of raw materials on behalf of licensees, 3) train operators of the first production plant, 4) develop the process further for special applications.

Jan 1, 1983