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This report is a compilation of all information obtained in accordance with the requirements of contracts S0122076 and H0232056. A series of eight coal mines were visited to determine their communications usage and requirements. Presently available equipment was surveyed and evaluated to determine its applicability to the needs of the mines. The equipment studied includes that made by the following companies: Anaconda Telecommunications Division Andrew Antenna Bendix Communications Division Collins Radio Group of Rockwell International Executone Communication and Sound Systems Gai-tronics Mine Safety Appliances Company Motorola Communications and Electronics, Inc National Mine Service Company Plessey Communications Systems Corp Pye Electronics Limited Reach Electronics Set Com Corporation Sonex Incorporated

Jan 1, 1974

By Joël P. T. Kapusta

Although Peirce-Smith converting remains the workhorse in matte converting, the copper and nickel industries are still confronted with production hindrances such as tuyere blockage, excessive refractory wear and limits in the oxygen enrichment levels of the blast air. The knowledge acquired on high-pressure gas injection technology as well as the invention of the concentric tuyere for steelmaking led to the development of the Air Liquide Shrouded Injector (ALSI) technology for copper and nickel converting. Following a technology demonstration in 1997-98 with four shrouded injectors installed in a Peirce-Smith converter, Falconbridge Limited implemented ALSI Technology on a commercial scale in May 1999 as an integral part of its new Slag Make Converter at Sudbury, Ontario, Canada. The paper presents the various aspects of commissioning ALSI Technology, as well as the operating changes and injector design modifications over the five years the shrouded injectors have been in operation.

Jan 1, 2005

By F. A. Rutledge, J. J. Mulligan, W. H. Kems, R. L. Thome

"As a part of the United States Department of the Interior program for the development and use of Alaska raw materials, the Bureau of Mines is conducting an investigation of deposits f nonmetallic minerals accessible to the Alaska Railroad for use in building materials in the Alaska Railroad-belt area. The results of the investigations, to date, indicate that raw materials for the production of brick products are in plentiful supply as clay in the Anchorage area, as fire clay at Sheep Mountain, and as shale in the Healy Creek coal formations near Healy, Alaska.Shale for the production of lightweight aggregate or Haydite occurs near mile 67 on the Glenn Highway, and preliminary tests give excellent results. Physical tests are new in progress on commercial-size concrete building units made with this aggregate. Another shale deposit in the same formation was located at mile 16 on the Matanuska Branch of the Alaska Railroad, and preliminary tests give comparable results.Natural lightweight aggregate in tree form of pumice and pumicite occurs in Katmai National Monument and has been used with excellent results in lightweight-building units in Anchorage and Fairbanks. These deposits will be investigated in more detail by the Bureau of Mines during 1952.One small perlite deposit near Healy, Alaska, showed excellent expanding properties, and the product compares favorably with commercial perlites being used in the States for plaster and concrete aggregates. Additional investigation by the Bureau of Mines to delimit the known occurrence and, if possible, discover others were planned for the 1951 field season.The pumice from Katmai National Monument also was considered for use as a pozzolan in pozzolan-portland concrete. Tests by the Bureau of Reclamation indicate that the pumice sample submitted by the Bureau of Mines would be satisfactory in strength development but is not outstanding. Natural activity is good and is greatly improved by calcination at 1,4000 F. Water requirements and shrinkage also are satisfactory. However, the material is ineffective in reducing expansion owing to alkali-aggregate reaction; and, if reactive aggregate is used to make concrete, it would not insure against excessive expansion. An attempt will, be made during the 1952 field season to delimit pumicite deposits along the Alaska Peninsula more amenable for use in pozzolan-portIand concrete.Because the Railroad belt has such a rigorous climate, insulation for new construction is of prime importance. Luring the Bureau of Mines, investigation of building materials all samples were submitted for chemical analyses as possible sources of raw materials for the production of rock wool, one of the best insulation mediums. Four areas having deposits of the required constitu¬ents were located as follows: Anchorage area, with Potter limestone and argillite; Cantwell-Windy area, with limestone and shale; West Fork of the Chulitna River area, with limestone and agrillite; and Homer-Seldoyla area, with Seldovia limestone and Homer clay. It was planned to take bulk samples of these formations and submit them for testing during the 1951 field season."

Mar 1, 1953

By B. Simser

At Brunswick Mine, an increase in the number of seismically-related falls of ground and in particular rockbursts occurred during 1999. This was due to the ever-increasing stress levels in the remaining ore reserves, mining in difficult highly stressed areas and in particular troublesome geological features. In conjunction with the Noranda Technology Centre, development of rockburst support systems started at the Brunswick Mine in 1996 and efforts were accelerated in 1999. A support package consisting of #6 gauge chain link mesh, #0 gauge heavy mesh straps, and a 1 m by 1 m pattern of modified conebolts was developed. The conebolts were modified to enable mixing of the resin anchoring. Two major rockbursts occurred during an intense seismic episode at the Brunswick Mine from October 13th to 17th , 2000.The area was evacuated approximately four hours before the first burst hit, and remained closed during the seismic ?flurry??. The first damaging activity occurred around midnight on Friday the 13th, and a second damaging episode occurred on the 17th that included a local Richter Magnitude 2.7 event. The second rockburst had dimensions of approximately 5 m by 5 m by 20 m or 2150 tonnes of massive sulphide material (density 4300 kg/m3). The first failure area was more extensive, caving approximately six metres of an intersection back with the lateral extent not safely measurable. This paper briefly describes the mining conditions that led to the bursting, the seismic response of the region, the mechanisms thought to have caused the bursts, and a yielding support system which had been partially installed before the burst.

Jan 1, 2002

By J Loimi, P Minkkinen, T Korpela

The head loss caused by metallurgical sampling for slurry streams can be reduced by metallurgical sampler design. When the process volumetric flow rate is reduced by vertical static cutters before the sampling by an equal number of moving cutters to the static cutters, the installation requires less installation head space than other sampling arrangements and is easy to accommodate at suitable locations in the process. Low head loss reduces building costs for the processing plant and operational costs during the lifetime of the plant.The presence of a possible systematic bias in the particle size distribution, solids density and elemental composition between an Outotec MSA 2/50 metallurgical slurry sampler sample and MSA 2/50 manually sampled reject have been studied by a customer. The paired samples were taken as simultaneously as possible. The customer evaluated the possible bias using a paired t-test and provided the assay results to Outotec for further evaluation.The results of the paired t-test showed no systematic bias in particle size distribution, solid density or assayed analytes, except in one analyte with low content and a high relative error. The high relative error in one analyte may have been caused by the same calibration model used in a X-ray fluorescence analyser for both high elemental-content concentrate and very low elemental-content tailings samples. The sampled stream is the tailings of a previous process stage.The results of the t-test were studied further using analysis of variance to reveal the error sources in samples. The results showed no bias between the samples collected from the MSA 2/50 reject and composite samples collected of the MSA 2/50 sample stream. The courier online analyser data was also available for evaluation of representativeness to the process stream.The analysis results of the courier online analysis reveals no bias between the MSA 2/50 reject samples, MSA 2/50 sample stream composite samples and online analysis results during the comparative sample collection period.CITATION:Loimi, J, Minkkinen, P and Korpela, T, 2017. Comparative evaluation of manual sampling and Outotec MSA 2/50 metallurgical slurry sampler, in Proceedings Eighth World Conference on Sampling and Blending , pp 167–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By D. F. Hambley

This report documents the work carried out by Engineers International, Inc. and its subcontructor, W. G. Pariseau, in order to develop a design manual for ore passes for open pit mines. The work included an extensive information search, novel analyses in rock flow theory, cost and time estimation for shaft and raise construction methods, and development of design criteria for the are pass proper, dump point, and draw point.

Jan 1, 1983

By E. S. Moore

"The Centre of the silver-producing section of the Gowganda area lies about 55 miles northwest of Cobalt, and the village of Gowganda is 71 miles by road from New Liskeard. The geological similarities of the Gowganda and Cobalt areas led prospectors westward from the rich Cobalt field, first to Elk Lake and then on to Gowganda, where mineralization was found in 1907. A year later many showings were found, and rich hand-picked ore was shipped. Most of the ore has come, however, from two mines, both of which are still operating; the Miller Lake-O'Brien, which was purchased by Siscoe Metals of Ontario Ltd. in 1945, and the Castle-Trethewey. The annual production of these two mines runs over one and one-half million ounces of silver and considerable cobalt. The total production of the camp has reached about 32,000,000 ounces of silver and a large amount of cobalt, the total not recorded.General GeologyThe general geology of Gowganda is in many respects much like that of Cobalt. There are areas of Keewatin basic and acid Javas mixed with tuffs and basic intrusions. These rocks are deformed and partly altered to schists, and have been intruded by some Haileyburian basic and ultra-basic rocks and by Algoman granite. These were followed by a large number of porphyritic Matachewan quartz diabase dykes. After a period of extensive erosion the Huronian sediments were deposited on a pene-planed surface over all the older rocks; these sediments include large quantities of conglomerate (partly tillite), quartzite, and greywacke. The Keweenawan rocks include the Nipissing quartz diabase sill, later quartz diabase dykes, and one long olivine diabase dyke, the latest Precambrian rock. The area has been extensively glaciated.Structural FeaturesThere has been little folding in the area since the Algoman batholiths were intruded, and the Huronian sediments lie nearly flat, with dips of 10, 15, or rarely 25 degrees. The Matachewan dykes show a remarkably uniform, nearly north strike, indicative of east-west tension when they were intruded. On the other hand, the dykes later than the sill strike nearly east, tangentially to the northeasterly and northwesterly strikes of the Miller Lake basin."

Jan 1, 1949

By Robert D. Perry

This report describes methods of reclaiming abandoned or inactive tailings ponds and dams. The investigated sites were selected tailings deposits adjacent to metal mines in the southwestern United States and the Pacific Northwest. The basic data developed for each site consisted of the following: a review of existing literature; a site visit that included sampling of the tailings and surrounding materials; laboratory and engineering studies; and development of reclamation plans. Laboratory tests determined the gold and silver content of each tailings deposit and the chemistry of the tailings and surrounding materials. Reclamation plans that include approximate costs were developed for five tailings deposit sites. These ranged in size from 52,000 to 103,000,000 tons. Our conclusions on the remining potential of each site are based on the tailings assay and other technical data. This study concludes that remining as a reclamation tool is feasible at certain sites. Included in this report is a remining program as part of the overall reclamation plan for two sites. Our preliminary results indicate that remining as a reclamation tool is feasible for only one of them.

Jan 1, 1981

By Charles L. Kusik

A study was conducted for the Bureau of Mines, U.S. Department of the Interior, to provide information which will lead to an increase in the recycling of mineral materials, in order to help conserve the Nation's mineral resources. Data were collected on energy requirements to recycle prompt industrial and obsolete scrap for nine metal commodities: Iron and steel, aluminum, copper, zinc, lead, stainless steel, titanium, tin, and nickel and nickel alloys. Major process routes for recycling were considered, starting from the first collection point through scrap preparation, transportation, smelting and/or refining to the molten metal, ingot, or other semi- finished form approximately equivalent to a primary metal of a similar composition. Available data for 1976 were collected on the amounts of each metal commodity recycled by major scrap categories. In addition, energy requirements were estimated for separating municipal solid wastes into four major categories: Refuse-derived fuel, and magnetic, aluminum, and glass cullet fractions. Finally, areas of research were identified to enhance recycling and/or increase the efficiency of energy use.

Jan 1, 1978

By Sabri Ergun

Cost estimates and technical feasibility are compared for six chemical coal cleaning technologies. The comparison is based on conceptual application of the chemical cleaning methods for removal of pyritic and organic sulfur from a utility grade bituminous coal. The process layout includes receipt of 8,000 tpd ROM coal, fine coal pulverizing, desulfurization, and preparation of a compacted clean coal suitable for storage and shipment. The methods are: the Magnex iron pentacarbonyl process, the KVB dry oxidation process, the Battelle hydrothermal caustic leaching precess, the TRW Meyers ferric ion leaching process, the Ledgemont oxygen/water leaching process, and the Bureau of Mines/Energy Research and Development Administration air/water leaching process. Capital costs estimated for the desulfurization operation alone, scaled to 8,000 tpd, range between $14 MM and $122 MM, while estimated operating costs for desulfurization alone on the same scale of operation range between $7 and $17 per ton clean coal produced. Relatively little is known about the chemical cleaning of coal, and present cost estimates indicate that the method might not be competitive at its present state of development when used alone to clean utility grade coals for sulfur removal. The principal attractiveness of chemical coal cleaning lies in its potential for combination with physical cleaning to produce cost competitive compliance coals in a combined process with high-Btu yields.

Jan 1, 1977

By C. B. Manula

Bituminous coal mining in the United States is currently experiencing a period of rapid growth which began in the early 1960's. Future demands are conservatively predicted to rise to 700 million tons by 1980 and to anywhere between 1 to 3 billion tons by the turn of the century. This means a continuous expansion of coal production by a factor of at least two can be expected before the end of the century. Over the last few years, production from underground mining has decreased; yet it is about 50% of the total coal output. In the absence of any discovery of near surface coal deposits, and even after conceding that some deeper deposits can be surface mined with changes in technology it can be reasonably assumed that coal production from underground will continue to play an important part in solving the energy crisis.

Jan 1, 1975

By Leonardo Lúcio de Araújo Gouveia

Este trabalho objetiva o estudo da influência da adição de fibras vegetais de bambu e cana-de-açúcar nas propriedades mecânicas do concreto. Para este trabalho foram confeccionados corpos-de-prova cilíndricos e prismáticos nos quais foram adicionados 2% e 5% em volume das fibras à massa do concreto. Após a cura, conforme NBR 5738 (2003) [1], os mesmos foram testados via ensaios de resistência à compressão conforme NBR 5739 (2007) [2], resistência à tração por compressão diametral, conforme NBR 7222 (2011) [3], resistência à tração na flexão conforme NBR 12142 (2010) [4] e módulo de elasticidade estático, conforme NBR 8522(2008) [5]. Verificou-se após os testes que todos os concretos produzidos atenderam a resistência mínima a compressão de 20 MPa, recomendado pela NBR 6118 (2003) [6] para fins estruturais. Foi observado um aumento da resistência à compressão em relação à mistura padrão. O concreto com adição de fibras de bambu apresentou melhor resistência mecânica em relação ao concreto com adição das fibras de cana-de-açúcar e ao concreto sem adição.

Aug 7, 2018

By Tatiane Haskel

A utilização de ligas Al-Si tem se expandido industrialmente principalmente no setor automobilístico. Cabeçotes, blocos de motor, rodas entre outros são exemplos de componentes produzidos com essas ligas. Estes componentes normalmente estão sujeitos a carregamento cíclico. O objetivo desse trabalho foi estudar o comportamento da liga A356 utilizando corpos de provas submetidos à fadiga por flexão rotativa nas condições brutas de fundição e tratadas termicamente por T6. Corpos de prova para ensaios de tração e de fadiga foram obtidos por fundição por gravidade em coquilhas. A comparação dos resultados foi realizada com os resultados do limite de resistência, do limite de escoamento, do alongamento e das curvas S-N. Adicionalmente análises fractográficas foram realizadas para verificar o comportamento de fratura. A liga tratada termicamente apresentou melhores resultados no ensaio de tração e de fadiga na faixa de 103<N<107.

Aug 16, 2017

By Mario Samamé Boggio

El presente texto describe algunos aspectos de la inversión extranjera en tres períodos: fines del siglo XIX, la primera mitad del siglo XX y segunda mitad del siglo XX. Dentro de lo quince casos analizados se halló que 5 empresas son iguales: Northern, Southem, Santander, Santa Luisa y Madrigal; 4 empresas se han "peruanizado" total o parcialmente: Caylloma, Ticapampa (Alianza), Lampa (Minsur) y Ruaron, 3 empresas se han agotado aparentemente: Santo Domingo, Salinas y Minas Ragra, 1 yacimiento revertió al Estado y fue desarrollado por Minero Perú: Cerro Verde; y 2 empresas fueron expropiadas y estatizadas: Cerro de Pasco Corporation y Marcona. En todos los casos no hubo descubrimiento del yacimiento por el inversionista, quien compró las concesiones y denuncios, con excepción de Marcona que estuvo explorado y desarrollado y fue contratado para su explotación.

Mar 1, 1982

By W. Wittke

SUMMARY: Geotechnical problems often lead to an increase of construction time and costs for large highway and railway projects. Some reasons, which have led to failures and thus to a delay of construction works as well as to increasing costs, are demonstrated by means of case histories, in which the author was involved as expert or planner. Proposals are made how to identify the reasons and to avoid repetitions. ZUSAMMENFASSUNG: Bei Großprojekten der Verkehrsinfrastruktur stehen häufig geotechnische Aufgabenstellungen im Vordergrund. Wegen geotechnischer Probleme kam und kommt es häufig zu Termin- und Kostenüberschreitungen. Anhand einiger Beispiele, bei denen der Autor als Gutachter und Planer beteiligt war, wird gezeigt, welche Ursachen zu Schadensfällen und damit auch zu Termin- und Kostenüberschreitungen geführt haben. Es werden Hinweise und Anregungen gegeben, wie die Ursachen erkannt und Wiederholungen von Schadensfällen vermieden werden können. RÉSUMÉ: À grands projets de l'infrastructure de la circulation, souvent des tâches géotechniques sont au premier plan. Par suite de problèmes géotechniques, souvent des dates et frais ont été dépassés. Au moyen de quelques exemples, à lesquels l'auteur participait comme expert et planificateur, les causes sont mises en vue qui menaient à des cas de dommage et par cela aussi à des dépassements de dates et frais. Des indications et suggestions sont données pour s'apercevoir des causes et éviter des répétitions de cas de dommages.

Jan 1, 2003

By CLARENCE WM. POY

THE most common difficulty faced by an engineer or mine operator when opening a new property in a new field is the lack of roads and of cheap transportation. This one item often swings the balance of success or failure in starting a project. In Alaska, as elsewhere, such problems are more or less serious. In the boom days around the Valdez district, as well as in other parts of this territory, freighting was accom¬plished by dog teams or horses, or even by men that were willing to put their shoulders into harness, because there were virtually no roads. More important, there was only one time when supplies could be transported, and that was when there was suffi¬cient snow on the ground following a heavy wind. Then, and only then, could one depend on the snow to support horses and sleighs, and be sure that the gulleys, streams, and crevices in the glaciers were filled with snow to avoid pitfalls. These methods were used when one had no roads, no streams in the summer to float a barge, or even a trail for a pack train. If the snow was deep and soft, trans

Jan 1, 1935

By P Lotz

With the recent increase in environmental awareness, gold mining companies are fast becoming signatories of the International Cyanide Management Code (ICMI, 2007). The objective of the Code is to improve the management of cyanide used in gold mining and to assist in the protection of human health and the reduction of environmental impacts associated with the use of cyanide. In particular the code specifies the following cyanide concentration limits: 50 ppm WAD cyanide in a tailings storage facility, 0.5 ppm WAD cyanide for effluents, and 0.022 ppm free cyanide or 0.022 ppm WAD cyanide as surrogate in the post mixing zone of river discharge. Weak acid dissociable (WAD) cyanide refers to those cyanide species liberated at a moderate pH of 4.5, such as HCN(aq) and CN-, and the majority of Zn, Cd, Cu, Ni and Ag complexes with low dissociation constants. It is potentially toxic to humans and animals. Gold plants using cyanide should ideally measure WAD cyanide online and destroy WAD cyanide in excess of the applicable limits to ensure compliance with the Code. Mintek has recently developed an online WAD cyanide analyser (WAD Cynoprobe). The WAD cyanide analysis technique is based on the use of a ligand exchange reagent that liberates WAD cyanide bound to metals such as Zn, Cd, Cu, Ni and Ag. The ligand exchange reaction is represented by the following chemical equation: Metal(CN)X + yLigand ↔ Metal(Ligand)y + xCN- The plant filtrate is treated with a ligand exchange reagent, to liberate WAD cyanide, before measuring the free cyanide concentration via amperometry. The WAD Cynoprobe measures both free and WAD cyanide concentration. Its fast analysis time, approximately five minutes, makes it suitable for use in the control and optimisation of the cyanide destruction and recovery process. The instrument has proven accurate and reliable in the analysis of synthetic copper, nickel and zinc cyanide solutions made up in the laboratory as well as under industrial gold plant conditions during various trials. The WAD Cynoprobe has gained widespread commercial acceptance and is currently implemented on nine gold plants around the world.

Jan 1, 2007

By Dimitrios Litsas, Michael Kavvadas, Panagiotis Sitarenios

"The paper discusses the results of 3D finite element analyses to investigate the effect of face support pressure and soil permeability on face stability conditions in EPB tunnelling. Two main types of face behavior are identified: Undrained conditions ahead of the tunnel face, typically occurring in soils with permeability less than about k=5·10-7m/s, are shown to be favourable for face stability; analyses show that an applied face pressure comparable with the initial hydrostatic pore pressure is sufficient for adequate face stability, even for soils of relatively low strength. Drained or partially conditions, typically occurring in soils with permeability higher than about k=5·10-6m/s, show that face stability is strongly dependent on the horizontal effective stress of the muck in the excavation chamber; the presence of even a small effective stress in the muck is very beneficial for face stability conditions and can be a possible explanation of successful EPB tunnelling through relatively permeable soils. INTRODUCTION Face stability is probably the most important aspect in urban tunnelling. Usually, Earth Pressure Balance (EPB) machines are utilized, to ensure that a reasonable amount of face pressure is exerted on the advancing excavation face, reducing ground loss and preventing potential instability of the face core, thus controlling the amount of disturbance caused by tunnel excavation to surface structures. However, the ideal amount of face pressure depends on several factors (ground and groundwater conditions, tunnel size and depth, muck conditioning, etc.) which are difficult to include in analytical calculations. For many years, conventional empirical or analytical methods (e.g. Anagnostou & Kovari 1996) were the only available tools for quantifying face stability and selecting the required face pressure. In the last few years, however, numerical analyses have gained power over conventional methods, allowing more accurate designs and providing useful information about the anticipated ground deformations due to tunnelling. Numerical analyses have also been used in assessing safety against face instability using face extrusion (horizontal face displacement) calculations (e.g. Prountzopoulos 2012)."

Jan 1, 2016

By Donald W. Foss

The Shiloh Church deposit is a very significant molybdenum occurrence in an ususual, perhaps unique, geologic environment. Work done to date indicate that several million tons of "ore" may be present, occurring as a matrix in limestone and dolomite breccias. Mineralized rocks cored to date are at or near the surface and the deeper resource potential has not been tested. The prospect is located in Polk County, north- western Georgia (Fig. 1). The "ore zone" was outlined by North American Exploration, Inc. (NAE) using geochemical prospecting techniques. Extensive geological work, including core drilling, has been conducted on the properties, together with geochemical and geophysical surveys. The geology, geochemistry and geophysics of the prospect are discussed. It is hoped that these data can be used to formulate exploration programs in similar terranes located elsewhere in the eastern U.S.A.

Jan 1, 1983

By Robert T. MacMillan

A process has been developed in the laboratory and expanded to semi-pilot-plant scale for recovering titania, iron, and byproducts from two types of titaniferous iron ores. A reducing roast with coke and soda ash followed by grinding and magnetic separation produced powdered iron and slag from which titania and byproducts were recovered by H2SO4 decomposition. Based on the steps tested on a. semi-pilot-plant scale supplemented by the results of the laboratory investigations, enough data are available to make a balanced flow sheet. Combined data from the laboratory and semi-pilot plant indicated that 85 to 9O percent of the titania content of the ore was recoverable and that approximately 90 percent of the iron could be recovered as a metallic-iron powder. Tahawus magnetite from the Maclntyre mine at Tahawus, N. Y., was successfully treated as follows: (1) The ore was roasted at 1,050° to 1,080° C. with carbon and soda ash, thereby reducing the iron to metal sponge and retaining the titania in the slag. (2) The metallic iron was separated, after wet grinding, by magnetic or gravity means. (3) The slag fraction was air-roasted at 850° C. and leached with NaOH to recover Na3VO4. (4) The leached solids received a dilute-H2SO4 leach to remove interfering impurities, chiefly Na2O and SiO2. (5) Titania was dissolved from the leached solids of step (4) by a H2SO4-bake followed by a water leach. (6) Titania was precipitated by seeding and boiling the resulting solution. The spent liquor was used for the dilute-H2SO4 leach in step (4). The following scheme was found to be technically feasible for recovering other byproducts of the process. (1) The gelled filtrate from the dilute-acid leach step was washed and dehydrated to produce a commercially acceptable silica gel. (2) The wash liquor containing sulfates of Na2O, Al2O3, Fe2O3, and TiO2 was combined with the highly alkaline filtrate from the wet-grind and metallic iron-separation steps, precipitating iron and titanium hydroxides, which were separated for special treatment. (3) Anhydrous Na2SO4 and Al2O3?3H2O were recoverable from the alkaline filtrate from step (2) by evaporation and carbonation, respectively, and the barren liquor was recycled to the magnetic-separation step.

Jan 1, 1952