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By R. J. Kendall

As we enter the new millennium, the South African mining industry has to ensure that it becomes more competitive if it is to survive in the ever more demanding global environment. Traditionally, mechanization in narrow stopes has been limited to the use of scraper winches, and numerous mechanization attempts have been restricted to pilot projects operated on an extremely limited scale (with varying degrees of success). The benefits of hydropower are well documented, and Northam Platinum has shown these benefits to be achievable on a mine-wide basis. However, the equipment originally developed for hydropower systems has followed the traditional labour-intensive approach commonly used in deep level narrow stoping operations. The problems experienced with the hydropower system are discussed and the rationale for developing alternate technologies is explored. The hydropower system has shown to be a versatile powering medium which can be harnessed for a diversity of uses. It (hydropower) enables the mining engineer to change traditional paradigms and to design an entirely new approach for optimizing the mining operation based on explosive techniques. The system developed for Northam consists of the following: ?Purpose-built stope drill rig operated off the hydropower system with special features to ensure accurate drilling patterns throughout the length of the blast hole ?Purpose-built high rate cleaning system for rapid transfer of fractured ore to the stope orepass ?Redesigned stope layout to facilitate in-stope water control and to recover fines from the run-off water ?Purpose-built drill rig for rapid establishment of reef raises and advanced strike gullies ?Purpose-built drill rig for flat end development. On both types of development end rig, emphasis is placed on ensuring accurate drilling patterns throughout the length of the hole to maximize linear advance per blast. The paper discusses the implementation of the Northam system on a large scale as well as current initiatives to further improve on the efficiencies of mining operations. It concludes by emphasizing that mechanized hydropowered stope technologies are in their infancy and thus offer unlimited scope in progressing beyond today?s paradigms to present as yet unthought of solutions for optimizing deep level ore extraction.

Jan 1, 2000

By Haskiel R. Shell

While the original purpose of the Bureau of Mines work on fluorine micas was to synthesize large single crystals or film suitable to replace natural muscovite or phlogopite, the objective was broadened to include development of the many possible fluorine micas as a class of new, unique materials. Several methods were developed for the synthesis of the fluorine micas at atmospheric pressure: Solid state reaction, melting in crucibles, internal resistance electric melting, and arc resistance electric melting. The latter two methods are now med commercially. A variety of fluoromicas were synthesized by isomorphic substitution including disilicic, trisilicic, and tetrasilicic. Fluorophlogopite, KMg3AlSi3O10F2, is the fluoromica most widely used. While most of the fluoromicas are completely stable to water, many water-swelling fluoromicas and fluoromontmorrilonoids were synthesized. Single crystals or film of the fluorine micas were grown to 2 inches or more by a number of methods, but none has as yet proved economical. In the report, detailed data and descriptions are given on compositions, syntheses, products, and uses, and on the properties including physical, dielectric, chemical, X-ray, optical, and structural.

Jan 1, 1969

By G. H. Lind

Seven full and partial pillar extraction operations were visited in New South Wales, Australia, in the early parts of 2001. Certain factors unique to these operations have led to the general success of the safe and economic extraction of these coal pillars. Some of these factors attributable to the overall success of these operations are discussed in this paper. In particular, geotechnical mapping, specific legislation pertaining to pillar extraction, mining methods, the role of temporary supports and training are described. It is found that some of these factors have useful attributes which could be used to design a methodology for extraction of underground coal pillars in the Witbank and Highveld coalfields of South Africa.

Jan 1, 2002

By John A. Breslin

The year 2010 will mark the 100th anniversary of the beginning of the research efforts by the U.S. government to improve the health and safety of miners working in the United States. This research began in 1910 with the establishment of the U.S. Bureau of Mines (the Bureau) and it has continued during the past 10 decades, even after the closure of the Bureau in 1996. The research on safer mining technology, formerly done by the Bureau, has now been combined with National Institute for Occupational Safety and Health (NIOSH) studies of miners? health to form a unified federal research program to improve the health and safety of miners. This article describes this research and places some of the accomplishments into perspective with other activities in the U.S. Mine Safety and Health Time Line (insert).

Jan 1, 2010

Many mines in Canada, the US and S. Africa are reaching the hoisting limit. Very little payload will be possible without compromising safety due the excessive weight. It has been suggested (DeLorme, 2000), that one of the most attractive concepts to enable deeper hoisting is to reduce the allowable factor of safety in the wire rope. Researchers at the Spokane Research Lab are developing new technology to improve hoisting safety and productivity by providing new monitoring and analytical tools. A Shaft Conveyance Monitoring System (SCMS) has been developed which determines hoist rope end load, true conveyance position and acceleration, and rope safety factor, as well as other hoist operating parameters. This information is transmitted to the hoist operator display 20 times per second. Recent field measurements on 45 mm(1 ¾ in.) diameter hoist rope indicate that dynamic forces during loading of a 9000 kg(10 ton) skip may exceed the safety factor of the rope. To improve on the current understanding of the mechanical behavior of hoist ropes, and to help interpret the results from field-testing of the SCMS, a new approach to computer modeling of stranded wire rope is also being developed. Particle Flow Code, PFC3D (Itasca 1995b) is used to simulate the structural behavior of wire rope and the interaction between individual strands when the rope is subjected to static and dynamic end loading. Details of the SCMS, field results from the measured rope loads, and the results of numerical modeling on the wire rope will be discussed.

May 1, 2002

By Henrique Severiano de Jesus

Para uma marcha estável do Alto-Forno é necessário o controle de inúmeras variáveis de sua matéria prima, no nosso caso a discussão é o Coque, elemento resultante de um processo Pirolítico do Carvão mineral, que tem um papel fundamental no processo de Redução do Alto-Forno, onde uma de suas fraquezas é a umidade, pois a sua eliminação propicia uma reação endotérmica, roubando calor do forno, com isso perde-se nos balanços de massa e de produção de Gusa. Mostrar de forma instrutiva o princípio de funcionamento de um Analisador de Umidade, Análise de Laboratório, entre outros.

Aug 17, 2017

Experimental results are presented for the anode overvoltage as a function of current density for different alumina concentrations in an alumina reduction cell. Voltage changes due to the electrolyte resistance and also the decomposition voltage, have been evaluated as a function of alumina concentration and anode current density. From these values of voltage, changes in the total cell voltage have been derived for changes in alumina concentration for different anode current densities. The results show that for each operating current density there exists a discrete alumina concentration that defines a minimum reduction cell voltage. Discussion is made about potential savings in power consumption when the alumina concentration is controlled.INTRODUCTIONThe standard procedure in the aluminium industry when analysing the cell-voltage required for the Hall-Heroult process for reduction of alumina, is to subdivide the total voltage into the following components (e.g. Pearson, 1955; Maritell, 1960).1. ohmic drop through busbars and joints2. ohmic drop through cathode lining3. ohmic drop through anode4. ohmic drop through electrolyte5. overvoltage at anode6. electrolytic decomposition voltage.(Overvoltages ,at the cathode are of negligible magnitude at all practical current densities.)It is understandable that the voltages assigned for each factor invariably differ for different workers...

Jan 1, 1965

By Charles E. Locke

CONTINUED expansion of gold mining in 1935 led to further developments in treatment methods. In base metals and non-metallics progress is also noted, coincident with greater activity. Statistics are not available yet for 1935 but the trend is shown by 1934 when nonferrous ore mined in the United States was 35,840,737 tons, or 45 per cent more than in 1933. The amount concentrated was 27,167,530 tons or 75.80 per cent of the ore mined, and flotation was used in whole or part on over 96 per cent of the ore subjected to concentration. In the crushing field a new model of the Fahrenwald crusher is promised soon. The Symons fine-reduction cone crusher and Traylor secondary crusher continue to gain as intermediate crushers. A new book entitled "Crushers for Stone and Ore" by William T. W. Miller appeared. The Hadsel mill has been improved still further and a number of installations are in satisfactory operation showing economical power consumption and low wear. An attempt in a

Jan 1, 1936

By A T. Spathis

The 11th International Symposium on Rock Fragmentation by Blasting (FRAGBLAST 11) was held in Sydney, Australia, between 24-26 August, 2015. The 93 papers, including six keynote presentations, covered exciting and practical topics in 20 sessions within 12 themes. Just fewer than 300 delegates from 27 countries attended. Four workshops were conducted on the weekend prior to the symposium, with three field visits after the symposium to Sydney region quarries, the Hunter Valley coal mining region, and the Kalgoorlie gold mining region. Delegates had the opportunity to visit the exhibition areas that showcased the latest products, software, hardware and systems in blasting technology. The keynote addresses were held in plenary sessions and set the tone for the parallel sessions that followed. They spanned the dynamics of the mining industry, the detonics of explosives, the interaction of stress waves and fracture mechanics in fragmentation, wall control blasting, and the importance of education and engineering for full process optimisation.

Jan 1, 2015

By TvS. von Moltke

Steel is a highly versatile material due to its low cost and good mechanical properties, but typically needs some or other form of corrosion protection due to its tendency to corrode when exposed to atmospheric conditions. In the case of organic coatings, the corrosion protection and functionality of the final product is critically dependent on the adhesion of the coating to the surface of the steel. In this work the effect of contaminants and the nature of the surface layers present on industrial steel products are investigated by means of paint adhesion tests, Auger electron spectroscopy (AES), and X-ray Photoelectron spectroscopy (XPS). It was found that the presence of sodium species on the surface is very detrimental to paint adhesion under wet conditions, while satisfactory adhesion may be obtained even in the presence of silicon and carbon residues. It was also found that the nature of the Fe-O layer, formed under wet conditions is labile and different from that formed in dry air, and that subtle changes in process conditions, such as changing the oxygen content of the quench water, may change the adhesion of paint to the surface of the steel. Lewis acid-base interactions are discussed as a mechanism that may determine the bonding between the steel and polymer coating.

Jan 1, 2003

By Cuppam Dasarathy

The incidence of liquid inzmiscibility in binar)) indium alloys has been theoretically analyzed on the basis of the Hildebrand-Alott equation. Bedictions of miscibility or otherwise Imve in general been found to agree with those phase diagrams that are already publislzed in the literature. Out of a total of 27 systems, where either the complete phase diagrams are published or liquid immiscible behavior is reported, the Predictions agree with the experimental data in 25 systems, the exceptions being the Te-In and Ni-In systems. According to the equation, liquid immiscibility is also indicated in the binary alloys of indium with K, Rb, Cs, Na, Sr, Ba, Ti, Zr, V. Nb(Cb), Ta, W, U, Re, Ru, Rh, Os, and Ir. RECENT investigations by the author have shown that indium when alloyed with iron, chromium, and cobalt shows liquid immiscible behavior.1"3 The Fe-In phase diagram shows a wide range of compositions where the liquids are immiscible.4,5 No intermediate phases are present in this system. No precise information is available about the extent of liquid immiscibility in the Co-In system. However, it is certain that there is a range of compositions where the liquids are immiscible and that there are two or three intermediate phases,376 in the system. Liquid immiscibility is also strongly indicated in the Cr-In system and no evidence was obtained in the brief investigation to indicate the presence of intermediate Cr-In phases.2 The present paper deals with a theoretical analysis of binary alloys of indium with certain elements of the periodic table and indicates the systems where liquid immiscibility may be expected. The incidence of liquid immiscibility in binary systems has been theoretically examined by many workers and many excellent papers are available on the subject. In this paper, the alloy systems are examined on the basis of the more recent ideas proposed by Mott.7,8 It has been claimed8 that the Mott parameter predicts the incidence of miscibility or otherwise with reasonable accuracy and consistency. BACKGROUND TO MOTT&apos;S APPROACH Hildebrand applied his immiscibility rule for non-polar liquids to various alloy systems.9 The basis of this rule is that the equation for the excess free energy of formation of a liquid solution is rather similar to the theoretical expression for the energy of mixing of a regular solution. He postulated that when the heat of mixing is sufficiently high, separation into liquid phases will occur and the condition for complete CUPPAM DASARATHY is at the Research Centre, British Steel Corporation, (South Wales Group), Port Talbot, Glamorgan, Great Britain. Manuscript submitted March 12, 1969. IMD miscibility was shown as where VA and VB were the atomic volumes of the components A and B, and ?EV the energy of vaporization of the component. The term (?EVA/VA)1/2 was regarded as a measure of the binding energy of the component A and was called the L&apos;solubility parameter" 8A. On this basis immiscibility occurs when 1/2(VA+VB)(bA-bBf > 2RT [2] Apparently, however, there were several inconsistencies in that according to Eq. [2] several systems known to be miscible in the liquid state were predicted as immiscible. MOTT&apos;S ANALYSIS ~ott&apos;" regards that the reason for the inconsistencies arising out of Hildebrand&apos;s equation was largely due to the electrochemical attraction between the two elements, not being considered. Hence, Eqs. [I] and [2] were modified by taking into account the electro-negativities of the two elements XA and XB, and Mott arrived at an equation for immiscibility, i(VA + VB)(6A - aB)2 - 23,Q60n(XA - XBf > 2RT [3j which can be written as i **&£*&* >&apos;*°™- &apos;• HI T being the melting point of the more refractory component of the system. In Eq. [4], the numerator was called the Hildebrand term, the denominator, the electronegativity term, and their ratio, the Mott number. Mott observed that if the Mott number of a given binary system was greater than the maximum number of Pauling bonds which the two metals could form, then liquid immiscibility could be expected. The maximum number of bonds formed by a given metal was considered to be directly related to the number of bonding electrons available, i.e., to its maximum valency. Since the valencies of the elements considered vary from 1 to 6, Mott assumed that if the ratio of the Hildebrand term to the electronegativity term was >6, then immiscibility could be expected. On the contrary, if the ratio is <1, the metals should be miscible. Further, the alloying behavior is not only influenced by the valencies of the two elements but also by the relative atomic sizes that influence the types of packing and hence the coordination number. Mott considers that on average the maximum number of near neighbors of unlike atoms is 6. Thus, on both valency and size factor considerations, Mott concludes that the maximum number of bonds&apos; possible in any system was 6, this being the upper limit of the Mott number for miscibility. In considering the alloying behavior of systems with Mott numbers between 1 and 6, Mott plotted the num-

Jan 1, 1970

By S. J. Broderick

[Huge camp heaps coat. in-.n,- ta._ur nd o tons of coal :&apos;efuse are a familiar sight in coa).--:1&apos;_ni`l ; res io The;;&apos; repre£e: t considerable economic loss, are very ~JZ&apos;:Si~i,tly, and tr:_ e u.: mach v lua-ble :price. Consequentl;;* their remcva7. is ,-,reatl:r de sir^~t~ a_." ar return that c,-u? be obtained would. be especially rel.co c to the coal T,-e "a_ste nat(~ria1 commrioes large pieces of bore cca1., lumps rf c12;&apos;, -)nd finer refuc3 coming from the &apos;acxcor~-, Tnc e&apos;-:s: rr;I refuso contains some Food coal. Th1S coal and the better crams of _,)ore Pre t&apos;--:e na.torials considered. in ohis in¬vestigotion. T&apos;.-.r, heavier fractions of the vas ier,,refuse a rd. the large pieces of slate a n i roc _r contain little carbcnacaous r..aterinl -.nd axe ~vir¬ tually worthless ra&apos;., :,atcria1. for activated carbon. In the E i 1i 11?&apos;ar 1 dictrict~ n1ab a :1 ut irfl percent of the&apos; coal mined is wa^,hed., and in district rc_a e -c-cnuatcs at the r..-ate of I to 2 Million tons a year?]

Jan 1, 1941

By Livia Mara Candido

As reservas de minério de ferro, apresentam tendências de menores teores de Fe, tornando maior a necessidade da redução da fração granulométrica inferior a 150µm, o que torna o processo viável tecnicamente por meio concentração. O método mais comum utilizado é a concentração através da flotação. Flotação é uma técnica de separação baseada na afinidade das espécies minerais com as moléculas de água. Na flotação reversa de minério de ferro, utilizam-se agentes que reforçam o caráter hidrofílico das partículas de Ferro, chamados de depressores. O mais comumente utilizado é o amido de milho em forma de solução, gelatinizado com a adição de soda cáustica. Dentro desse contexto e afim de aumentar o poder de gelatinização do depressor, foram realizados através do planejamento fatorial estatístico, ensaios de flotação em bancada, com diferentes concentrações iniciais e finais de amido de milho presente na solução e ainda a relação de amido/soda para avaliar o impacto sobre a recuperação metalúrgica da flotação, concluindo-se que recuperação metálica foram fortemente influenciados pela concentração inicial da solução de amido.

Oct 30, 2017

By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice, pitwall profiles are often planar in cross-section within each rock layer; i.e., the profile inclination across each layer tends to be constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties, and factor of safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e., the planar profiles exhibiting the same FoS) up to 8° depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Feb 9, 2022

By Timothy J. Rohrbacher

This report presents results from an ongoing U.S. Bureau of Mines study defining domestic coal reserves. Examinations of five 7 ½ -minute central Appalachian quadrangles have been completed to date. Only 26.4%, 5.0%, 6.5%, 8.2%, and 4.2% at the coal resources remaining in the Matewan, Boltsfork, and Hoskinston, KY; Vansant, VA; and Beckley, WV quadrangles, respectively, constitute economically recoverable reserves. An evaluation of the coal mining industry&apos;s impact on the economy of Pike County, KY, wherein the Matewan quadrangle is located, was also completed in order to provide a basic understanding of the influence of coal mining on the local economy. Results show that coal mining is the only major income producing industry in Pike County, accounting for about 46% of the county&apos;s income, and 21% of the total available employment, in the base year 1990. If similar results are found in subsequent investigations, a strong argument can be made that traditional coal producing regions may soon be experiencing resource depletion problems far greater and much sooner than previously thought. This will affect not only the coal industry but, given the obvious dependence of Pike County&apos;s economy on its coal mining industry, the entire social and economic infrastructure of large areas.

Jan 1, 1994

By J. Bertisen, G. Davis

Previous analyses of small samples of mining projects have found that feasibility studies tend to well under-estimate the actual capital costs of the project. Our review of 63 mining and smelting projects completed over 4 decades confirms that as-built capital costs are, on average, 25% higher than as estimated at the bankable feasibility study stage. There appears to be little attenuation over time of this bias in capital cost estimation, at first appearing to reflect an absence of learning on the part of the consulting engineer. We instead argue that this persistence of bias is intentional, driven by a scarcity of project financing and the need to inflate the project economics in a bid to secure financing. Around this intentional bias is a considerable amount of scatter. Roughly half of all projects’ as-built capita costs fall outside of the expected ±15% of the feasibility study capital cost estimate, even after allowing for intentional estimation bias. Cost overruns of 100% or more happen in roughly 1 out of 13 projects. The data reveal that a shifted lognormal probability distribution should be used when modeling mining project capital costs in a Monte Carlo analysis.

Jan 1, 2007

By AIME AIME

COMMITTEES. LOCAL COMMITTEE.-R. C. Crawford, Chairman; Harrison W. Craver, Secretary; Julian Kennedy, Taylor Allderdice, E. W. Pargny, Charles L. Miller, W. H. Rea, S. A. Taylor, M. E. Wadsworth, W. A1. Henderon, A. C. Dinkey, W. L, Jones, E. L. Messier, George Mesta, J. H. Jones, G. H. Riley, S. L. Goodale, D. W. McNaugher. LADIES&apos; COMMITTEE.-Mrs. Taylor Allderdice, Chairman; Mrs. Julian Kennedy, Mr. R. C. Crawford, Mrs. E. M. Herr, Airs. J. W. Marsh, Mrs. T. A. Mellon, Mrs. G. P. Bassett, Jr., Airs. D. M. Clemson, Mr. Charles L. Miller, Mrs. V. L. P. Shriver, Mrs. W. A. Bostwick, Mrs. A. C.. Dinkey, Mrs. A. P. Childs, Jr., Mrs. F. R. Dravo, Mrs. Hermon Griffin, Mrs. W. H. Nimmick, Mrs. F. H. Lloyd, Mrs. S. G. Cooper, Mrs. S. H. Church, Mrs. E. N. Ohl. The Institute Headquarters was established at the Hotel Schenley, where a bureau of information was maintained for the benefit of the visiting members and guests of the party during the time of the meeting. TECHNICAL SESSIONS. The first session, held Tuesday evening, Mar. 1, 1910, in the large lecture hall of the Carnegie Institute, was called to order by Harrison W. Craver, Secretary of the Local Committee. Mr. Craver introduced Dr. John A. Brashear, who extended to the members and guests a hearty welcome to the city of Pittsburg, to which David W. Brunton, President of the Institute, responded. The following papers were presented in oral abstract by the authors: Biographical Notice of Dr. Charles B. Dudley, by Dr. R. W. Raymond, New York, N. Y. Biographical Notice of William Metcalf, by Col. II. P. Bope, Pittsburg, Pa. Development of Hindered Settling Apparatus, by Robert H. Richards, Boston, Mass. (Illustrated by lantern-slides.) A Few Mining Districts in the Argentine Republic, South America, by Z. S. Beyl. (Illustrated by lantern. slides.)

Apr 1, 1910

By Bruno Alves Resende

Em julho de 2010, a linha de Tiras a Quente da Usiminas, planta de Ipatinga, passou a operar com um novo sistema de controle para o laminador de acabamento. Assim, foi necessário atualizar o simulador offline de set up do Trem Acabador, utilizado frequentemente pelas áreas técnica e operacional. Para isso, toda a lógica de cálculo e formulações matemáticas do sistema online foram assimiladas e empregadas no novo simulador. Os resultados das simulações, quando comparados com os valores gerados pelo modelo online, mostraram-se bastante confiáveis. Sendo assim, conclui-se que o aplicativo desenvolvido está apto para ser utilizado como uma ferramenta de simulação offline do modelo de controle do Trem Acabador. Os benefícios potenciais do uso do simulador são: (i) aumento da produtividade por meio da redução de paradas da linha, (ii) melhoria da qualidade final do produto, (iii) redução do número de experimentos na produção e (iv) ajuste dos parâmetros dos modelos de controle. No presente trabalho são apresentadas e discutidas as características do desenvolvimento, da apresentação e da aplicação desse simulador.

Aug 17, 2017

By B. J. Moore

This publication contains analyses and related source data for 352 natural gas samples from wells and pipelines in 18 States and 5 foreign countries. All of the samples were obtained and analyzed during calendar year 1974 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economics. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Sixteen previous publications have presented the results of 10,479 gas analyses prior to 1974. The first three, Bulletins 486,4 576,5 and 617,6 contain analyses and related source data on

Jan 1, 1975

By Greaves M. C

X-ray fluorescence spectroscopy used for the analysis of mill samples results in improved control of flotation concentrators.Techniques and equipment for sampling pulp streams, filtration and drying, grinding, briquetting and X-ray fluorescence analysis of samples have been developed.The current methods in use permit the analysis for lead and zinc in six pulp samples within 30 min total elapsed from the start of sampling. The X-ray method gives a precision at least equal to the former routine wet-way assay methods.The equipment is used also for pilot plant control, as a means of solving complicated analytical problems and in the rapid qualitative analysis of exploration samples.INTRODUCTIONIn milling and concentrating operations, classical methods for the assay of lead and zinc have been mainly of use for accounting purposes and for the post-mortem examination of plant operations, but have been of little value for rapid mill control. Where attempts have been made to apply these methods to control assaying, it has been necessary to modify the procedures and introduce short cuts which have tended to reduce their reliability.Even with these shortened procedures, the time taken to obtain a limited amount of information rendered them of little value for the control of milling operations where sudden, large fluctuations can occur. In recent years, a number of new and rapid analytical techniques, based on physical rather than chemical principles, have been introduced.These include direct reading emission spectroscopy, x-ray fluorescence spectroscopy and atomic absorptionspectroscopy.

Jan 1, 1964