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The transition from low stress to high stress conditions is a challenge eventually faced by most mines in Australia that extend to depths greater than (generally) about 1000 m. In areas with strongly adverse 'stress versus depth' gradients, such as some parts of Western Australia, significant stress-related problems have occurred at depths as shallow as 300 m below surface. The actual depth at which the 'transition' occurs is a function of the local pre-mining stress field, the strengths of the various rock types hosting the deposit and the layout and sequencing adopted in the mine. Stress-related damage can result in increased support costs, and delays associated with rehabilitation and disruption to production. In the worst case, where strong seismicity and associated damage occurs in active mining areas, 'exclusion' zones and 're-entry' protocols may be required. These can severely disrupt production. A key aspect of managing the transition is the recognition of the onset of stress-related ground behaviour. Damage mapping can be used to develop understanding of the relationships between mining activities and the local and regional response to them. Carefully documented case histories provide a basis for calibrating numerical models. This paper discusses some of the typical styles of ground behaviour observed in higher stress conditions in underground mines. A simple damage classification scheme is described to assist in 'damage mapping' of mine tunnels. An example of damage mapping is presented to illustrate an approach commonly used for recording stress-related damage.

Nov 25, 2010

By David C. Russell

The Department of the Interior used to be a quiet, noncontroversial, almost boring agency. It, after all is the fifth oldest of the Departments, and as an old line Federal agency it has studiously performed its preservation and resource management functions in a caretaker mode--though some would say more "undertaker" than "caretaker"--locking up the body and soul of America piece-by-piece. Yes, quiet, serene. That is until Jim Watt showed up. And we have all seen that version of Mt. Vesuvius which resulted--only it was the environmentalists who blew their tops. Ronald Reagan chose Jim Watt as Secretary of this fine old agency to prove that one-third of our Nation's land and over a billion acres on the Outer Continental Shelf can work for this Nation. At the foundation of President Reagan's charge to Secretary Watt is a belief in the tenets of the free enterprise system, and in the individual freedoms upon which this country was founded. There are those who don't share this belief in democracy and free enterprise, and those who believe this 205 year experiment called the United States of America will fail. Nikita Krushchev said "we will bury you"--obviously he didn't agree with our system. An Italian sociologist, Franco Ferrorotti, said bureaucratic stagnation will kill capitalism. Certainly we have all felt the ravages of bloated bureaucracies. Perhaps one indicator in the United States is the Federal Register, that daily compilation of Government's largesse. In 1970, 20,000 pages of the Federal Register were published. A decade later, in 1980, that volume had quadrupled to 80,000 pages. The Federal bureaucracy can stagnate from excessive budgets as well. The Interior Department spent $60 million on administering Federal coal leasing in 1981. That's nearly two bits a ton for every ton of coal leased in 1981. You wouldn't stay in business very long if your administrative overhead on inventory was that outrageous. But the pessimism of our critics is apparent from more than red tape and bloated budgets. For decades America has been fasting--consuming too little of America's wealth of minerals, subsisting instead on a diet heavily reliant upon mid-east oil, with little emphasis or concern for inventorying and developing domestic energy and mineral resources. Economics--yes. But short-term, short-sighted economics. Excessively dependent upon foreign imports, of oil, cobalt, chrome and other strategic minerals, the U.S. measures its time before another embargo--or fallen Shah, or Soviet manipulation, or Saudi shift, or, as we witnessed in Egypt, assassination--an untimely loss to mankind and efforts to bring peace to the troubled mid-east. These disruptions, in addition to their tragic human tolls, impair the free world's security. Huge chunks of the United States have been locked away in dozens of single land use categories in the name of conservation, with only the foggiest idea of what resources might be denied the American people-and this at a time of unacceptable levels of energy and strategic mineral imports. More than half and perhaps two-thirds of all Government-owned lands are totally withdrawn from or severely restricted to development under the mining and leasing laws. We must continue to rid Government of the overly zealous restraints which have been keeping us from drawing upon that which can help restore our economy and national security. When we assumed responsibility, the United States was dependent on foreign sources for about 40 percent of its oil. In 1981, our oil import bill was approximately $83 billion--nearly 17 times what it was in 1972. Our reliance on foreign sources for essential minerals is even more disturbing. We must look to other countries--some unfriendly, some unstable--for 22 of 36 strategically critical minerals. Yet the energy resources on federal lands which are owned by the American people could meet our needs for centuries if properly managed. Eighty-five percent of the crude oil yet to be discovered in America is likely to come from public lands, as will 40 percent of the natural gas, 35 percent of the coal, 80 percent of the oil shale, nearly all of the tar sands, and substantial portions of uranium and geothermal energy. Our vast hardrock-mineral wealth includes untapped deposits of essential elements we now import, such as chromium, copper, platinum, and cobalt. The obvious question is, if these abundant resources can help to revitalize our economic strength and to preserve our national security, why aren't we using them to better advantage? To a large extent, the answer can be found in past decisions to restrict public access to the federal estate, thus deferring to us or our successors the tough decisions that flow from Congress' mandate to provide for environmentally responsible development of America's energy and mineral treasures. Here is the legacy this Administration inherited: In January 1981, 7 years after the onset of the Mideast oil embargo: ---Less than 15 percent of federal onshore lands were under lease for oil and gas development; ---No oil and gas leases had been issued in Alaska for 15 years;

Jan 1, 1982

By R Hao

Uncertainties in large open pit geotechnical modelling has been a major concern for slope stability analysis. The level of confidence in the in-put assumptions, such as structural and rock mass model, dictates the modelling results to some extent. This article is to detail a case study of Kalgoorlie Consolidated Gold Mines (KCGM) regarding a predicted inter-ramp failure on an as-built pit walls by a 3D numerical modelling. Significant concerns were raised across site and multiple preventive plans were considered. After intense data collection work, it was confirmed that the risk of failure had been overestimated. The case study has improved the understanding of geotechnical data in-put and has enhanced the process of creating and updating geotechnical structural models at KCGM.

Jun 22, 2022

By G M. Jones, J Rademan

Debswana, owned by the Government of the Republic of Botswana (GRB) and De Beers in a 50:50 joint venture partnership, operates the Jwaneng diamond mine in Botswana - the most valuable diamond mine in the world. The mine provides between 60 - 70 per cent of DebswanaÆs earnings, and about 30 - 40 per cent of the GRBÆs income. In 2008, the company embarked on the Cut 8 Project - an open pit waste cut-back to expose more diamond bearing ore to sustain mine life by another six to seven years. This undertaking was much larger than previous cut-backs; it increased the waste stripping ratio threefold, increasing significantly the waste handling fleet of trucks, shovels and infrastructure, and impacted a large part of the materials handling plant which required replacement with new facilities. The project coincided with the beginning of the Global Financial Crisis (GFC) and a slowdown in the economy. Its $4 billion total life cost was billed as æthe largest private investment project in BotswanaÆ which produced heightened expectations amongst stakeholders that it would redress some of the issues brought about by the GFC and leave behind a legacy of jobs, increased opportunities for citizen owned business and improved social infrastructure.Most of the big project challenges were non-technical and ranged from dealing with various stakeholders?at?all levels, a 25 per cent currency depreciation of the Botswana Pula against the South African Rand, obtaining work permits for non-citizens in a job starved environment, managing construction to world class safety standards, managing the low productivity of construction workers and producing a viable legacy program that satisfied the GRB and stakeholders. Whilst most of these risks were identified in front end studies, the magnitudes were in many instances underestimated. Managing this uncertainty on Cut 8 can provide valuable lessons to other projects in a similar environment, or at least provide the information to indicate that these factors should be adequately provided for in the financial evaluation of a project in the form of budget, schedule, contingency or risk mitigation.CITATION:Jones, G M and J Rademan, 2012. Reliability of expert judgements and uncertainty assessments, in Proceedings Project Evaluation 2012 , pp 109-116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By J. Wayne Erickson

One of the major problems facing today's mining industry is how to manage people and control costs in the underground mine. It is a problem with a solution. Because of the concerted effort to find and mine minerals near the surface, open-pit mine opportunities for certain minerals are becoming more limited; the mining industry will eventually be forced to produce more and more from underground mines in order to obtain those resources necessary to sustain our civilization. Although much technical progress has been made towards solving problems associated with the underground mine, such as - mine design, ventilation, rock support, equipment, and blasting techniques, little has been written on managing mining personnel. Much of what is being taught and practiced today about human relations, motivation, incentives, etc., applies to the underground miner, but the uniqueness of his group dictates a different treatment from that associated with the typical construction worker or factory employee. The difference lies with the kind of man attracted to underground mining and his working environment. Anyone who has had the responsibility of managing an underground mine would agree it is a unique problem.

Jan 9, 1976

By L N. Loganathan

Risk exposure in tunnel projects is extremely high due to various factors such as variability of subsurface conditions, selection of inappropriate design and tunnelling methods, improper risk assessment on adjacent surface and subsurface structures and utilities, and inadequate contractual practices. The risks in tunnelling must be borne by the contractor, designer and the owner of a tunnelling project. There have been a number of improvements in the last ten to 15 years in the manner in which tunnel projects are developed and implemented in terms of their design, construction, financing and operations. One significant improvement has been the manner in which underground conditions and their risks are being managed. Owners are less willing to transfer the full responsibility to the contractor for managing the underground conditions, although this is a familiar manner in which underground major urban projects have been previously contracted and managed. The owners of tunnel projects in Singapore have advanced the risk management process for their projects through geotechnical interpretative baseline reports (GIBRs), geotechnical data reports (GDRs) and project specifications (PSs). This paper discusses industry practice and its development as well as the application during the preparation and use in Singapore on the Deep Tunnel Sewerage System (DTSS) and the Marina Coastal Expressway (MCE) project in Singapore. The DTSS trunk sewer is 48 km and ranges from 3.3 m to 6 m finished diameter up to 50 m below the ground. The underground conditions ranged from Old Alluvium, strengths of about 1 MPa to competent Bukit Tima granite, with strengths of over 230 MPa. The total route length of the MCE is about 5 km. About 3.6 km will be constructed underground, consisting of dual five-lane carriageways. The underground construction will be cut-and-cover, and 2.6 km will be constructed about 13 m underground, and 1 km of tunnel will range from 13 m to 24 m as the tunnel passes under a 420 m wide reach of Marina Bay, whose crossing will be constructed as a two-phase cofferdam.

Jan 1, 2008

By Ronald D. Mariani, Gregory E. Mahoski

BACKGROUND The steel and iron ore industry has had a long history of an adversarial relationship with its union and workforce. The Empire Mine during its first 40 years of existence was no exception. The "we-they" mentality went hand-in-hand with the normal by-product of an adversarial relationship, grievances and arbitration. This relationship was considered the norm and it was not until the late 1970s that consideration was given to changing this relationship. At this time the industry was involved in a fight for existence and the economic pressure demanded increasing productivity to lower cost. The challenge to survive highlighted the fact that an adversarial relationship was not conducive to attaining the needed gains in productivity. The first formal attempt to change the way we worked came in the 1980 Labor Agreement which provided for the opportunity to utilize Labor Management Participation Teams (LMPTs). LMPTs were established at the Empire Mine and they functioned for a couple of years. The teams spent most of their time working on creature-comfort issues and steered clear of dealing with productivity issues. Mine shutdowns had occurred in Michigan resulting in large layoffs, and the union was trying to add jobs and was not supporting teams that could increase productivity and eliminate jobs. When the 1986 labor negotiations began, the local union pulled their support of the LMPT process. Other initiatives were negotiated over the years to foster a change in the culture but, as with the LMPT program, they did not produce the desired culture change. It became abundantly clear: you cannot negotiate a culture change.

Jan 1, 2004

By B. T. Dawson

In today's work world, constant changes are a fact of life. Downsizing and technological advances are two of the most prominent concerns for employers and employees alike. In this article, the author addresses some of the emotional consequences of these changes and offers a new, empowering perspective for coping with them.

Jan 1, 1998

By W. J. Weymark

"The Gregg River project is located 40 kilometres southwest of Hinton, Alberta, adjacent to and east of Jasper National Park. This metallurgical coal mine has been developed as a joint venture between Gregg River Coal Ltd. (a subsidiary company of Mana/ta Coal Ltd.) and seven Japanese companies. This 200-million dollar project consists of a conventional truckshovel open-pit operation and a coal preparation plant rated at 2.14 million tonnes of clean coal per year. Mining operations started in October 1982 with plant start-up following in April 1983. Introduction This paper is an overview and update of the Gregg River project, a metallurgical coal mine being developed as a joint venture between Gregg River Coal Ltd. (a subsidiary of Manalta Coal Ltd.) and seven Japanese companies. The Gregg River Coal leases cover 3440 hectares and are located 40 kilometres south of Hinton, Alberta, adjacent to and north of Cardinal River Coal Mine (Fig. 1). This 200-million dollar project consists of a conventional truck-shovel operation and a coal preparation plant rated at 2.14 million tonnes of clean coal per year. A total of 31.5 million tonnes of clean metallurgical coal will be sold to the Japanese over a fifteen-year term. At present, mining operations are ahead of schedule and the plant started up on schedule in April 1983. Access and Climate An all-weather road, Highway 40, connects the minesite with Hinton (the nearest commercial centre) and a Canadian National Railway (C.N.R.) spur line connects the minesite with the C.N.R. main line in Edson. Hinton is accessible by road chartered airline and rail. ' ~h~ rug~ed and varied topography in the area creates large vanations m temperature and precipitation over short distances. The region is characterized by precipitation throughout the year long cold winters and short cool summers. The mean temperatur~ of the area range from a low of -14°C in January, the coldest month, to a high of 12°C in July, the warmest month. Long-term precipitation data indicates a mean yearly precipitation of 870 mm of which 620Jo occurs during the summer months."

Jan 1, 1985

By Ivan César Lopes Diniz, César Romero Afonso Goulart Júnior

Mandrels are tools applied to manufacturing seamless tubes. In VSB plants (Vallourec Soluções Tubulares do Brasil), it is used in two mills. Mandrel and PQF Mills. This is an expensive tool due its alloy (hot work tool steel – AISI H13) and lengh (between 12 meters and 22,5 meters). An opportunity to apply mandrels from PQF in Mandrel Mill has been identified. However, mechanical properties of PQF mandrels must be improved. This work presents the heat treatment process of Quenching and Tempering developed internally at VSB to improve PQF mandrel properties aiming to achieve Mandrel Mill requirements. Hardness and metallography tests were performed before and after some steps of the heat treatment to characterize and validate the process.

Oct 5, 2019

By Richard P. Stahura

During the next five years, there will be a trend toward performing belt cleaner maintenance while the conveyor is in operation. Most mines and industrial sites that use belt conveyors have an in-house safety rule that the belt must be stopped before maintenance work can be performed on any belt-cleaning device. This is a good rule. Most cleaning devices are positioned against the belt with hardware that requires the service technician to reach or climb into the chute to change the cleaning blades. But this simple rule becomes more complicated as production demands require higher conveyor availability and provide fewer conveyor outages. In many cases, today’s conveyors are expected to be available 98% to100% of the time.

Jan 1, 1996

By Julio Auzmendi

Dado que algunas industrias utilizan material a granel en sus procesos, este puede presentarse en fábrica, envasado, en sacos a granel, camión cisterna o volquete. Sin embargo, se generan problemas de diversa índole Por lo que el presente texto describe los posibles problemas encontrados cuando las industrias utilizan este tipo de materiales como: problema de recepción, almacenamiento y extracción, transporte a la zona de preparación o mezclado, dosificación y transporte a las máquinas del proceso y transporte del material elaborado a los puntos de consumo, así como las soluciones.

Sep 1, 1982

By Charles H. Jacoby

In 1774 a Swedish chemist, C. W. Schule, first recognized manganese as an element. That same year Schule's associate, J. G. Gahn, isolated the element manganese for the first time. In 1856 the Bessemer process of steelmaking gave birth to the economic importance of manganese. Later, in 1882, Robert Hadfield discovered high manganese steels. Although the primary use of manganese is in the ferroalloy industry, two additional important uses for manganese are making chemicals and dry cell batteries. Manganese is also vital to plant and animal life. Various chemical compounds of manganese are used in fertilizers, feeds, glass manufacture, paints, varnishes, and for numerous medicinal and chemical purposes. For the study of industrial minerals and rocks, only the chemical and battery grade material is of concern, but for the sake of comparison, metallurgical aspects are included in this presentation. Although currently the world's largest consumer of manganese, the United States is producing only minor amounts of ore at the present time. This is due primarily to the fact that although huge deposits of manganese occur within our borders, all are of such low grade as to be economically unfeasible to mine. For many years various government agencies and segments of private industry have devoted sizable sums of money and time in an attempt to upgrade ores from the various deposits, and also in an attempt to recover manganese from blast furnace slags. In view of current world prices, and the quantity of high grade material available, there is little likelihood that any of these approaches will be found to be economically feasible in the near future. Geology and Mineralogy Mineralogy There are over one hundred minerals that contain manganese. These minerals vary from those with compositions that are predominantly manganese to those having only minor percentages. [ ] Geology From a geological standpoint most manga¬nese deposits are complex. In general, it can be said that all primary deposits of manganese are carbonates or silicates. The most productive and profitable have been those of sedimentary origin and residual concentrations. Examples of these residual types of deposits are associated with the metamorphosed lodes of Madhya, Pradesh, India, and the lateritic deposits of Orissa and Bihar, India; nodules in the residual clays of the Philippine Islands, U.S. southern Appalachians and Arkansas, Ghana, and Brazil. Sedimentary manganese deposits are best exemplified by the Nikopol district of Russia and the Tchiatouri area of Georgia, USSR. Hydrothermal replacements are characterized by the rhodochrosite deposits of Butte and Phillipsburg, Mont. In general, the hydrothermal type deposit has not resulted in any large tonnages being produced, but may have given

Jan 1, 1975

By Charles H. Jacoby

In 1774 a Swedish chemist, C. W. Schule, first recognized manganese as an element. That same year Schule's associate, J. G. Gahn, isolated the element manganese for the first time. In 1856 the Bessemer process of steelmaking gave birth to the economic importance of manganese. Later, in 1882, Robert Hadfield discovered high manganese steels. Although the primary use of manganese is in the ferroalloy industry, two additional important uses for manganese are making chemicals and dry cell batteries. Manganese is also vital to plant and animal life. Various chemical compounds of manganese are used in fertilizers, feeds, glass manufacture, paints, varnishes, and for numerous medicinal and chemical purposes. For the study of industrial minerals and rocks, only the chemical and battery grade material is of- concern, but for the sake of comparison, metallurgical aspects are included in this presentation. Although currently the world's largest consumer of manganese, the United States is producing only minor amounts of ore at the present time. This is due primarily to the fact that although huge deposits of manganese occur within our borders, all are of such low grade as to be economically unfeasible to mine. For many years various government agencies and segments of private industry have devoted sizable sums of money and time in an attempt to upgrade ores from the various deposits, and also in an attempt to recover manganese from blast furnace slags. In view of current world prices, and the quantity of high grade material available, there is little likelihood that any of these approaches will be found to be economically feasible in the near future. Geology and Mineralogy Mineralogy There are over one hundred minerals that contain manganese. These minerals vary from those with compositions that are predominantly manganese to those having only minor percentages. [Chemical Mineral Composition % Mn Hausmannite Mn304 72 Polianite MnO2, 63.1 Pyrolusite MnO24 60-63 Cryptomelane KR8O16R (R=Mn) Variable PsilomelaneBa Mn Mn8O16 (OH).45-60 CoronaditePb R8O16R (R=Mn) Variable Hollandite Ba R8O16R (R=Mn) Variable Manganite Mn2O3•H20 62 Braunite 3 Mn2O3•MnSiO3 62 Tephroite 2 MnO•SiO2 54.3 Rhodochrosite MnCO3 47 Rhodonite MnSiO3 42 Spessartite 3 MnO•AI2O3•3SIO2 33.3 WadHydrous Mn OxidesVariable Franklinite(Fe Mn Zn)O(Fe Mn)sO3 Variable Asbolan Cobaltiferous wad Variable AlabanditeMnS63.14] Geology From a geological standpoint most manganese deposits are complex. In general, it can be said that all primary deposits of manganese are carbonates or silicates. The most productive and profitable have been those of sedimentary origin and residual concentrations. Examples of these residual types of deposits are associated with the metamorphosed lodes of Madhya, Pradesh, India, and the lateritic deposits of Orissa and Bihar, India; nodules in the residual clays of the Philippine Islands, US southern Appalachians and Arkansas, Ghana, and Brazil. Sedimentary manganese deposits are best exemplified by the Nikopol district of Russia and the Tchiatouri area of Georgia, USSR. Hydrothermal replacements are characterized by the rhodochrosite deposits of Butte and Phillipsburg, MT. In general, the hydrothermal type deposit has not resulted in any large tonnages being produced, but may have given

Jan 1, 1983

By John M. Warde, Eileen P. Burke

ORES of manganese and chrome have a high order of strategic importance, both metals are basic to the metallurgy and usefulness of steel, the fabric on which our economy rests. Looking beyond the current recession and short range picture of oversupply in these ores, this review attempts to answer the following questions regarding the longterm outlook for these key commodities: By 1970, what will be the probable demand here and abroad, what are future supply prospects, and what effect is the USSR likely to have on the world market? (See summary forecast on facing page.)

Jan 8, 1958

By I. Fafoutis

Laboratory column studies were conducted in order to assess the effectiveness of slag and red mud reactive barriers for cleaning up leachates generated at mining and waste disposal sites and loaded with copper and manganese. Solutions containing the metals of concern were prepared by dissolving the required quantities of CuSO4?5H2O and MnSO4?H2O in distilled water so that Cu concentration was 100 ppm and Mn 20 ppm. Flow rates of 25 mL.h-1 for Cu solution and 75 mL.h-1 for Mn solution were used in order to simulate aquifer water velocities of 1 ft/d and 3 ft/d respectively. Solutions were pumped upflow, in Plexiglas laboratory columns filled with each reactive medium, using peristaltic pumps. Measurements of middle and outflow column pH, redox potential, conductivity and elements concentration were performed to provide information regarding removal mechanisms for both elements and exhaustion/inactivation rates for each reactive medium. Both reactive media showed fairly good removal efficiency over the period studied. Copper was mainly removed by precipitation and formation of Cu(OH)2 while removal of manganese was due to precipitation of Mn(OH2).

Jan 1, 2006

Individual specimens of sphalerite from the Broken Hill lode vary considerably in manganese and iron contents, even within the same orebody, so that study of the overall variation of manganese and iron content of the sphalerite calls for the analysis of a large number of specimens. This difficulty has been overcome by analysing a series of recleaned zinc concentrate products, prepared from stope samples and their equivalents, from most of the developed sections of the lode. The analyses reveal that during the formation of the sphalerite the concentrations of iron, manganese and zinc in the mineralizing solutions varied independently of one another from place to place in the forming orebodies, and also in time.The overall pattern of variation of the iron and manganese contents of the sphalerite in the several orebodies of the lode bears a general resemblance to the overall pattern of distribution shown by several other elements, notably, cadmium, lead, bismuth and arsenic. The iron content of the sphalerite indicates that it was formed at a temperature of 6000 C. or higher, but the variation in its iron and manganese contents demonstrates that Kullerud's method for determining the temperature of formation of sphalerite from its iron content must be used with caution if only single specimens of sphalerite are available.INTRODUCTIONThe four chemical analyses available of specimens of practically pure sphalerite from the Broken Hill lode (Table 1) reveal that the manganese content of the sphalerite varies considerably, and that there is a significant variation in its iron content. The variations revealed between individual specimens within the same orebody in the same mine suggest that specimen material is unsatisfactory as a basis for studying the overall manganese and iron contents of Broken Hill sphalerite, unless a great number of specimensis analysed.

Jan 1, 1956

By W. M. Williams

"Although manganese is a metal virtually unknown to the layman, it is hardly necessary to point out to the engineer the importance of manganese in modern metallurgy, an importance intimately linked with iron (and steel), the basic materials of engineering construction for hundreds of years and certain to remain so for long into the future. World steel production will approach and perhaps reach 1 billion tons/year in the 1980s; with a manganese content between 0.5% and 1 % in ordinary steels, and more in specialty steels, manganese use worldwide will soon approach 15 million tons annually. Manganese was discovered and isolated in Sweden in 1774 by Karl Wilhelm Scheele (who also discovered molybdenum), but the element was only of scientific interest for several decades. By the early part of the nineteenth century, however, manganese oxide had become commercially available and was in use for colouring glass and for the production of chlorine. Commercial application in metallurgy appears to have been limited to the manufacture of crucible (or ""cast"") steel, a highquality product made by carburizing wrought iron, and melting it in small batches to make ingots which could be rolled and used for special applications, e.g. for the manufacture of fine tools or for ""steeling"" the cutting edges of implements such as wrought iron axes and chisels.* However, it was not until Bessemer's epoch-making invention of cheap steel in 1856, and the dramatic expansion of the steel industry thereafter, that manganese assumed the importance that it holds in modern steelmaking."

Jan 1, 1999

By Reginald S. Dean

THE commercial availability of electrolytic manganese has greatly changed the position of manganese as a nonferrous alloying metal. Manganese metal commercially available up to about ten years ago was reduced with either silicon or aluminum and contained substantial amounts of the oxides of these metals and other impurities. Manganese was accordingly not available as an alloy base and its addition to copper-base and nickel-base alloys was generally limited to a manganese content of a few per cent. Several special alloys like manganin contained up to 12 pct of manganese. A method for the production of electrolytic manganese was developed by the Bureau of Mines in 1936 and commercial production was begun in 1938. At the present time (June 1951), production is about 12 tons per day but appears likely to be substantially increased. Electrolytic manganese is deposited from an aqueous electrolyte containing manganese and ammonium sulphates and is marketed as cathode fragments about 1/8 in. thick. The impurities in its composition are as follows: iron, 0.0015 pct; copper, 0.001; arsenic, 0.0005; cobalt, 0.0025; lead, 0.0025; molybdenum, 0.001; sulfide sulfur, 0.017; sulfate sulfur, 0.014; insoluble, 0.002; carbon, 0.002; hydrogen, 0.015. These figures are from Bulletin 463, U. S. Bureau of Mines. From an alloying standpoint, the most important impurity is hydrogen. This can be removed by heating; 95 pct of the hydrogen can be removed in this way without introducing significant amounts of oxygen or nitrogen. Much of the commercial electrolytic manganese used in alloys is dehydrogenited by the producer, since the amount

Jan 1, 1953

By Reginald S., Dean

The commercial availability of electrolytic manganese has greatly changed the position of manganese as a nonferrous alloying metal. Manganese metal commercially available up to about ten years ago was reduced with either silicon or aluminum and contained substantial amounts of the oxides of these metals and other impurities. Manganese was accordingly not available as an alloy base and its addition to copper-base and nickel-base alloys was generally limited to a manganese content of a few per cent. Several special alloys like manganin contained up to 12 pct of manganese.

Jan 1, 1953