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NEW MEMBERS The following list comprises the names of those persons who became members during the period Jan. 1, 1917 to Feb. 10, 1917. ALLEN, ROBERT SEXTON, Chief Chemist at Concentrator, Inspiration Cons. Copper Co. Globe, Ariz. ALTIO, KARL FREDRIK, Min. Engr., The Sissert Mining District Co., Ltd., Polefskoy Zavod, Perm Government, Russia. ARGALL, PHILIP HENRY, Mgr., Ozark Smelt. & Min. Co., Magdalena, New Mexico. BAILEY, MARC Supt., Wolverine & Arizona Min. Co., Bisbee, Ariz. BAKER, DAVID FRANKLIN, Asst. Supt. of Blast Furnaces, Alan Wood, Iron and Steel Co., Swedeland, Pa. BATES, BENNETT R, Min. Engr 1025 Peoples Gas Bldg., Chicago, Ill. BECK, HOWARD A Shift Foreman, Aurora Cons. Mines Co. Aurora, Nev. BELL, LEO RICHARD Casilla 270, La Paz, Bolivia, South America. BENJAMIN, FLOYD SHAW, District Mgr., Aetna Explosives Co., Inc., 800 Torrey Bldg., Duluth, Minn.

Jan 3, 1917

In the 100 years since the formation of The Australasian Institute of Mining and Metallurgy there have been significant changes in all aspects of the mining industry.A number of the changes have been driven by technical evolution or necessity, others have been driven by developments in the application of the products produced from the mining of minerals. Other changes have been driven by shifts in community values.

Jan 1, 1993

By Research Staff ? Verde Copper Mines

FLOTATION is now commonly practiced in alkaline ore pulps, yet little is known regarding the action of the alkaline solutions on the ore particles beyond the fact that films of oxidized material form. We wish to chronicle our discovery of the presence of soluble reducing agents in alkaline ore pulps of the United Verde, and present some data on lime consumption. During the grinding and flotation of a pyritic ore containing small amounts of ferrous sulfate and other soluble salts, an excess of lime was added to precipitate the salts, and filtered samples of the solution were titrated with standard permanganate solution. Even in pulps of high causticity an appreciable permanganate titration was always obtained, in spite of the fact that the solutions were shown to contain little iron. Investigation of the cause brought about the discovery of several previously unsuspected compounds in flotation pulps made from pyritic ore. Not only the reducing agents present had to be identified, but also the amount of dissolved oxygen, and a survey was finally made of the free oxygen content and reducing agents of the mill pulp in the concentrating mill at Clarkdale. A great many compounds might form, caused by oxidation of pyrite or other metal sulfides or by reaction between a lime solution and pyrite. The most probable compounds considered were calcium sulfides; polysul-fides, thiosulfates, and polythionates. Later it was discovered in the literature that in alkaline pulp polythionates do not exist and if introduced. are decomposed into sulfites and thiosulfates.1 Any precipitated sulfur is changed by alkali into thiosulfate and polysulfide. Sulfites and sulfides react to form thiosulfate, so that in the end it is possible to have in an alkaline solution only thiosulfate and an excess either of sulfide or sulfite. Confirmatory tests were made and it was finally established that the alkaline mill pulps made from the United Verde ore contained

Jan 1, 1929

By Robert W. Phelps

It is gratifying to observe the growing interest in the study of oil-well spacing. It should always be held in mind that the problem of optimum spacing is to obtain the maximum return of capital per acre drained. This naturally evolves.into a mathematical consideration. As mathematics is the basis of all science, an effort should be made to develop formulas which involve data obtainable in the early stages of development. The first information from a discovery well in a new field would be the character of the sand, rate of initial production of oil and gas, viscosity of the oil, rock pressure, etc. Later, from this well, if Herold's theories of hydraulic, volumetric and capillary controls are accepted, could he determined the ultimate production as without interference from drainage by subsequent well completions, and under which control the well is producing. If it should prove to be producing under capillary control, a rough estimate could be made of it's radius of drainage. With but one well, the radius of drainage, or the interference of drainage of individual wells by close spacing, would be estimated by comparison with similar conditions in other fields in which the development has progressed sufficiently to furnish the data. A second well that is spaced sufficiently close so that an interference can he observed after its ultimate production is estimated, will furnish data to develop a desirable spacing of wells which can be inaugurated for that area and which is capable of producing a uniform amount of oil under like conditions. In some fields this area will be extensive, in others each well location will require an individual study. In 1924, Cutlerl developed a scheme whereby he determined by tabulation a spacing of oil wells for the maximum return per acre. After a study of production in a number of fields, he developed the following as a tentative rule: "The ultimate production for wells of equal size in the same pool where there is interference (shown by a difference in the, production decline curves for different spacing) seems approximately to vary directly as the square roots of the areas drained by the wells. This rule may also he stated thus: The recovery from wells of equal size

Jan 1, 1929

By Lukas Erkurt, Wolfgang Holzer, Stefan Auderer, Richard Gradnik

SEM/ NATM Tunnelling contracts in Austria and Germany are usually tendered applying unit price contracts. The purpose of this paper is to show how contractual problems are resolved in these countries. The focus will be put on describing the theoretical approach, several case studies will show how contractual problems were dealt with on site.

Jun 23, 2024

By S. Lee, F. Campero

"Past heap leach design has evaluated hydrodynamic parameters based on a uniform particle size of heap material, but has ignored the equal importance of the instability of fine migration within heap stack in the beginning stages of the irrigation process. The proposed probabilistic model evaluates internal fine erosion and segregation potential of well-graded crushed ores by considering the entire particle size distribution shape and site compaction degree. Using this model, unsaturated flow model parameters were successfully evaluated based on synthesized soil-water characteristic curve (SWCC). Additionally, one-dimensional unsaturated transient flow modeling with Hydrus 1D® showed that the different recovery efficiencies of heap material under unsaturated flow patterns depending on the particle size distribution and compaction degree of heap material. Agglomeration preprocess employed by most heap leach sites can reduce the potential of fine erosion within heap material significantly, but internal stability of crushed ores and hydrodynamic-based analysis of heap material’s pore structure is equally important in the prescreening stage in order to improve efficiency of the heap leach and avoid a costly agglomeration process. INTRODUCTION Accurate estimation of heap leach recovery is a difficult task due to the variety of design parameters that need to be considered - such as geochemistry, hydro-dynamics, and geotechnical design aspects, most notably particle size distribution through the process of agglomeration. After agglomeration techniques were introduced to heap leach design, the influence of particle size distribution and compaction degree in enhanced heap leach recovery has been neglected. The main purpose of agglomeration is to prevent fine segregation and internal erosion during and after heap stacking for well graded crushed ores, which will eventually diminish heap reach recovery. Recent studies show that agglomerated heap materials that had been consolidated at 10 meters below heap surface can release the fines after contact time with lixiviant to the compacted heap material and produce poor drainage performance (Milczarek et al, 2013). It must be noted that engineers and practitioners should investigate feasibility of agglomeration benefit prior to heap leach design because the agglomeration process can incur up to 20 or 30% of project costs. Internal stability of stacked heap material is mainly governed by the particle size distribution of crushed ores. Depending on this stability, segregation and internal erosion of fines can be mitigated by the application of moderate compaction effort during heap construction. Investigation of segregation and internal erosion potential therefore takes precedence for well graded crushed ore since reaction time and contact area with lixivant are greater in finer ores."

Jan 1, 2016

The importance of the accurate determination and interpretation of the bulk density and porosity of a given iron ore deposit is very often disregarded or neglected. Large amounts of time and money are spent on delineating and testing orebodies, and yet one of the most important factors in resource evaluation is sometimes estimated or, at best, determined from existing data from similar deposits. The Thabazimbi and Sishen South iron ore deposits are two well-known economical occurrences of high-grade iron ore in South Africa. Both these deposits formed as secondary enrichment of banded iron formation lithologies. Ongoing density studies on both these deposits are underway and results thus far proved very effective and necessary. Small-scale methods are used to determine average values for different ore types on both deposits. These values are used in resource estimation and geophysical interpretation.

Jan 1, 2007

By Shengli Wu, Jiacong Zhang, Mingyin Kou, Bingjie Wen, Heng Zhou

The COREX process, which is considered to be able to replace the blast furnace, still has some gaps to reach the designed productivity. The metallization degree is regarded as one of the limitations of the COREX process. In the present work, several parameters affecting the metallization degree of direct reduced iron (DRI) are analysed by SPSS software (Statistical Product and Service Solution). Melting rate, oxidation degree of reducing gas, oxidation degree of top gas, top gas consumption per ton of burden, temperature of reducing gas, and burden distribution index are con firmed as the main factors affecting metallization degree. Based on this, a linear equation has been developed for predicting metallization degree. Additionally, improving the melter gasi fier vault temperature appropriately, increasing the proportion of high volatile matter coal, and optimizing the type and particle size of iron ore and the pattern of burden distribution have been shown to improve the metallization degree.

Mar 1, 2018

By Hitoshi Ogura, Koichi Kobayashi, Sadao Yabuuchi

"In Japan, most pile foundations using pre-cast concrete piles are installed by the bored pre-cast piling method, wherein pre-cast piles are installed in holes that have been excavated beforehand and filled with cement milk (term used for cement water slurry in Japan). The bored pre-cast piling method with enlarged base, in which the portion near the toe is enlarged during boring operation, is widely used because of the cost benefits and the increased vertical bearing capacity that this method offers.The EX MEGATOP method, further developed as an improved bored pre-cast piling method with enlarged base, is reported here. The features of this method are: (1) High vertical bearing capacity; (2) High degree of freedom in design; (3) Excellent workability; and (4) Friendly to the environment. In particular, high vertical bearing capacity can be obtained using nodular piles and by enlarging the area at the pile toe and shaft. This method can gave a vertical bearing capacity coefficient at the toe of a=430, more than twice the corresponding value of a = 200 of a conventional bored pre-cast pile. Moreover, the shaft resistance can be several times larger than that of a conventional bored pre-cast pile. This report gives an overview of the EX MEGATOP method, evaluation of vertical bearing capacity, and examples of application of the method.1.lntroductionMost pile foundations in Japan are installed by the bored pre-cast piling method, that is, in holes that have been excavated beforehand and filled with cement water slurry, referred to as 'cement milk'. The ""bored pre-cast piling method with enlarged base"" is frequently used. In this method an enlarged excavation is used near the pile toe to increase the vertical bearing capacity.The EX MEGATOP method is a variation of the bored pre-cast piling method. Its features include the use of nodular piles and a long, enlarged excavation. The vertical bearing capacity of the EX MEGATOP method is described in this report."

Jan 1, 2005

By Francis M. Rice

Before the world-wide depression, the primary purpose of most blast-furnace operators was to produce a maximum tonnage of pig iron per day for each furnace in blast. Some attention was paid to the conservation of labor and raw materials, but the idea was well established that low-cost pig iron was attainable only when each furnace was producing a high tonnage. After the depression had set in, the picture changed considerably. Each blast-furnace operator was forced to run his plant in a manner that best fitted the economical set-up of his company. A great deal of thought was expended on the different methods of operation, always with the idea of making each product in a way that would best serve his company financially. Because of this abnormal condition, the blast-furnace man was compelled to indulge in various practices of which many had been believed to be next to impossible up to that time. The ultimate purpose of these innovations was either one or a combination of the following: 1. To produce only enough pig iron for immediate consumption at a minimum cost. 2. To produce gas for boiler or mill use to supplant some higher priced fuel. 3. To consume the coke produced at the coke plant, which was often viewed as a byproduct. 4. To protect the cash position of the company. These conditions were met by diverse methods, some of which were: 1. Slow or decreased wind. In some instances the blast blown was held as low as 25 per cent of the normal volume. 2. Intermittent operation, in which the furnaces were shut down or "fanned" at frequent intervals.

Jan 1, 1935

By D. G. Westlake, U. F. Kocks

WHILE single crystals of most materials with cph lattice structure show essentially unlimited ductility, polycrystalline specimens of the same materials exhibit the entire range of ductilities. A difference between the ductility of single crystals and polycrystals may be associated with the special stress concentrations to be expected, for example, at the intersections of slip bands or twin lamellae with grain boundaries. Whether such stress concentrations prove catastrophic depends on the cleavage strength of the material, the size of the stress concentrations, and the speed with which they are formed. Thus, the ductility may vary in degree from material to material. Another possible reason for differences in ductility between single crystals and polycrystals is that a sufficient number of independent deformation modes must be available to insure compatibility between the macroscopic strains in neighboring grains.''2 This criterion is often taken to be a necessary condition for any polycrystal ductility whatsoever, not as one that determines different degrees of ductility; thus, a material with an insufficient number of independent deformation modes would have to be brittle as a polycrystal. The "sufficient number" is five if every grain is to accommodate arbitrary shape changes ("von Mises criterion "). We should like to argue that fewer than five independent modes may be sufficient to satisfy compatibility conditions; and that the internal stresses set up when the plastic strains are not compatible reach the theoretical fracture stress only after a significant amount of macroscopic strain has taken place which may vary in magnitude from case to case, allowing an influence on the degree of ductility. Experimental evidence for these statements is taken from the following review of the number of independent deformation modes observed in the various cph

Jan 1, 1968

By Francis M. Rice

Before the world-wide depression, the primary purpose of most blast-furnace operators was to produce a maximum tonnage of pig iron per day for each furnace in blast. Some attention was paid to the conservation of labor and raw materials, but the idea was well established that low-cost pig iron was attainable only when each furnace was producing a high tonnage. After the depression had set in, the picture changed considerably. Each blast-furnace operator was forced to run his plant in a manner that best fitted the economical set-up of his company. A great deal of thought was expended on the different methods of operation, always with the idea of making each product in a way that would best serve his company financially. Because of this abnormal condition, the blast-furnace man was compelled to indulge in various practices of which many had been believed to be next to impossible up to that time. The ultimate purpose of these innovations was either one or a combination of the following: 1. To produce only enough pig iron for immediate consumption at a minimum cost. 2. To produce gas for boiler or mill use to supplant some higher priced fuel. 3. To consume the coke produced at the coke plant, which was often viewed as a byproduct. 4. To protect the cash position of the company. These conditions were met by diverse methods, some of which were: 1. Slow or decreased wind. In some instances the blast blown was held as low as 25 per cent of the normal volume. 2. Intermittent operation, in which the furnaces were shut down or "fanned" at frequent intervals.

Jan 1, 1935

By Kevin Connor

The mineral industry in Burundi was a minor contributor to the country's gross domestic product (GDP), which was estimated at just $1 billion for 19812. Coffee and tea continued as the Nation's major export commodities. Mineral exports consisted of small tonnages of wolframite, cassiterite, and baetnasite. Burundi's trade balance of payments situation worsened in 1981, with import payments more than double export revenues. Petroleum imports alone equaled 46% of the export revenue total. By year-end, the only indigenous fossil fuel source to have been found in Burundi was peat, which the Government had been attempting to develop to alleviate some of the petroleum import requirements. In June 1981 the Irish Peat Development Authority, Bord na Mona, signed a 4-year contract with the Burundian Government to supply technical staff for the ongoing peat project work there. Funding for the project was provided by the VS. Agency for International Development and the Government of Ireland. The new contract, which was an extension of ongoing peat research there, represented Burundi's increased awareness of the value of its large peat reserves for both energy and agricultural uses. At yearend, Burundi's Ministry of Public Works and Mines was does to selecting a contractor to study the feasibility of developing Burundi's phosphate deposits. The study would determine the potential for establishing fertilizer production facilities based on the country's phosphate reserves at Matongo-Bandaga, The study's specific objectives are to prove mineral reserve tonnage and grade, draw up mining and processing facility designs, estimate capital and production costs, and conduct a regional market and distribution survey. The cost of the study was estimated at slightly over $1 million, and it should take approximately 16 months to complete. The proposed project will mark the Burundian Government's first step in its plan to exploit on a large scale its natural mineral resources for advancing its agriculture-based economy. Burundi was dependent on imports, which are expensive to transport inland from coastal ports, to supply its domestic requirements for fertilizer. It was planned that part of the fertilizer production from the

Jan 1, 1983

By Aly M. Mohammad

Croton Point Avenue Bridge carries Croton Avenue over Metro-North main tracks at Harmon Rail Yard in Westchester County, New York. The new bridge is 1100 foot long and 36 foot wide nine span structure with three spans continuous units. The spans are steel multi-stringers, composite with concrete deck. The piers are solid wall piers and the foundations are spread footings. During the design of the bridge foundations it was determined that the relatively loose to medium dense sand layer is susceptible to liquefaction under a design earthquake with a seismic coefficient of 0.15g. Several foundation options were considered for the new bridge including both shallow and deep foundations. It was determined that the most cost effective alternative is to use spread footing foundations supported on densified soils. Vibratory probes were utilized to densify the loose to medium dense sand layer and reduce the risk of liquefaction. Densification test sections were performed to determine the optimum spacing for the vibro probes. The test sections included performing piezocone tests before and after the densification to compare the increase in relative density of the sand. In addition, ground surface settlement due to the vibro probes was measured and correlated to the increase of soil relative density. The paper will present the results of the ground improvement method utilized and correlate the spacing of the vibro probes and the increase in relative density and the results of the piezocone tests performed before and after the densification. It was found that the vibro probes are not as effective as thought at shallow depth below the ground surface. It is believed that the results and finding presented in this paper will benefit both the design and construction industries by providing a relatively cost effective means to improve the soils

Jan 1, 2007

Reduce or prevent acid mine drainage from coal refuse piles and surface mines by inhibiting the growth of acid-causing bacteria. Approach A dilute surfactant or deter? gent solution is applied directly to coal refuse piles or overburden using a hydro-seeder or road watering truck. The surfactant treatment can be used either as a preventive measure to avoid a potential acid drainage problem or to reduce water treatment costs by controlling acid drainage at its source. How It Works Acid drainage is prevented or reduced by inhibiting the growth of Thiobacillus ferrooxidans, a type of bacteria which obtains most of the energy it needs to survive by oxidizing ferrous iron in water. The oxidized iron in turn attacks pyrite, which forms an acid and additional ferrous iron for the bacteria to oxidize. T. ferrooxidans is protected by an outer membrane which enables it to survive in its acid environment. Anionic surfactants, or surfactants containing negatively charged ions, can be used to destroy this membrane, thus killing the bacteria and slowing down the oxidation of acid-forming pyrite. Of the anionic surfactants tested to date, sodium lauryl sulfate (SLS) appears to be the most effective as a bactericide. Alpha olefin sulfonate and alkyl benzene sulfonate are acceptable alternatives. These surfactants are major components of common household products, such as laundry detergent, shampoo and toothpaste. They are, therefore, readily available, inexpensive, biodegradable and present no environmental problems at low concentrations.

Jan 1, 1983

By Keith G. Kirk, Lawrence E. Welborn, Patrick A. Ley

Over the past two years the Office of Surface Mining in conjunction with Energy & Minerals Technology Assessment, ENCORE Systems Inc., and Boeing Computer Services has developed the Economic Coal and Ore Reserve Estimation (ENCORE) Coal Seam Modeling System. This system is being used by OSM, certain states, and industry for mine planning and mine plan permit review. The ENCORE system enables the mining engineer to start at the reserve estimation stage of surface mine planning and continue through the entire mine planning process and into the permit preparation process. The ENCORE system enables the state and federal regulatory authorities to assess a given mining and reclamation plan permit application in a rapid and efficient manner and greatly speeds up the mine plan review and permitting process. The ENCORE system is user friendly and menu driven thereby permitting the engineer with minimal computer training to rapidly learn and utilize the system. Data are input both through digitized map files and bore hole information files and stored in a data base that is an integral part of the ENCORE system. The system performs reserve estimation through standard polygon methods, least square methods, and geostatistical (kriging) techniques. Geostatistical routines permit rapid evaluation of coal and overburden quality and quantity. System outputs include drill hole sumnary and resource summary reports, cross sections, isopach maps, structure contour maps, premining topography maps, postmining topography maps, and three-dimensional perspective views. The maps can be displayed on a high-resolution, color graphics terminal or generated by a high quality plotter and are suitable for direct inclusion in the mining and reclamation pl an permit application. This paper gives detailed examples of ENCORE'S use together with example outputs.

Jan 1, 1983

By Arthur A. Center

AT the beginning of 1944 it was expected that the production of metallic zinc in the United States from domestic and foreign concentrates would exceed the 1943 figure though domestic production of concentrates was expected to drop below the 1943 rate, mostly in the Tri-State area. Imports of concentrates were estimated to more than take care of such deficiency. North American concentrate production, available for import to the United States or elsewhere during the year, was estimated at over 200,000 tons recoverable zinc content; South American at about 65,000 tons; Australian at about 50,000 tons. Production of both concentrates and metal in the United States, however, did drop, attributable in considerable part to man-power shortage in the industry. However production exceeded consumption, which fell off, and stocks of metal increased. These stocks have increased since the middle of 1942 but production and consumption are coming nearer to a balance. The A, B, and C premiums, which have played an important part in keeping up domestic production of concentrates, extend only to the middle of 1945 by present legislation. Congress is being asked for their continuance during the war and

Jan 1, 1945

By Mariana Sizenando Lyrio, Weslley Luiz da Silva Assis, Harison da Silva Ventura, Gabriella Maria Silveira de Sá, Paulo Rangel Rios, Ana Gabriella Conceição dos Santos

A nucleação em contornos de grão é uma das mais importantes na maioria dos metais utilizados em engenharia. Um exemplo clássico é a nucleação de ferrita no contorno de grão austenítico, mas este tipo de nucleação também é predominante na recristalização. Nesse trabalho, simulações computacionais são realizadas de modo a estudar a transformação de fase nos contornos de grãos equiaxiais e nos contornos deformados. Os grãos equiaxiais são representados por poliedros de Poisson-Voronoi e os grãos deformados por elipsoides de diferentes razões de aspecto. Os resultados são comparados como os modelos analíticos de JMAK e CAHN. A microestrutura final não é visivelmente afetada pela razão de aspecto dos poliedros predecessores. Todavia a cinética de transformação dos grãos recristalizados é significativamente alterada.

Nov 9, 2019

By L Dawson, S Carr-Cornish, N Boughen, K Moffat, S Masterson

The risk and consequences of community rejection and loss of a social licence to operate is well articulated (Moffat et al 2018), however, the means for systematically managing this risk are less established. At the local scale, a mining operation is said to have a social licence to operate (SLO) when it achieves ongoing acceptance or approval from the local community and other stakeholders who can affect its profitability (Graafland, 2002). Without this social acceptance, it is very difficult for a business to operate effectively or profitably. It is well understood that social (or community) acceptance of a mine and its associated operations is a reflection of the quality of the relationship a company has with their host community (Thomson & Boutilier, 2011; Lacey & Lamont, 2014; Parsons et al., 2014; Moffat et al., 2015). Community relations are an integral part of successful mining operations and where these interactions are effective, they tend to foster mutual understanding, trust and support between a company and the host community (Kemp et al., 2006; Holley & Mitcham, 2016). Research further demonstrates that where such interactions are perceived to be procedurally fair, the increased trust created in these company-community interactions tends to lead to higher levels of acceptance of mining operations (Moffat & Zhang, 2014; Lacey et al., 2017).The challenge, however, is how to listen systematically to communities that mining and associated operations; communities that are often located across vast geographic areas and with diverse demographics. To date, traditional methods deployed to both guide and evaluate community engagement and social investment activities have been challenged to reflect the nature of the phenomenon they seek to observe, the voice of community. For example, detailed baseline surveys of community attitudes every three years by companies, as is the requirement within the policy frameworks of most large miners, provide rich insights but do not reflect the dynamic, temporal nature of the relationships that underpins their SLO. These processes typically are largely opaque to communities and distinct from the company’s engagement activities. The CSIRO Local Voices project was developed with Rio Tinto to go some way towards meeting this challenge of how to listen to the voice of community systematically. CITATION:Moffat, K, Dawson, L, Carr-Cornish, S, Boughen, N and Masterson, S, 2018. Listening to Local Voices – a systematic approach for understanding what a social licence to operate means for Rio Tinto in the Pilbara, in Proceedings Life-of-Mine 2018, pp 8–11 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By G. Nuñez, M. A. Pathak, C. F. Stanley

"A 1986 report by the U.S. National Committee on Blomechanlcs (1) describes lung disease as a major national health problem. The report cites three areas that would benefit from a better understanding of the vibratory patterns of the lung. These areas are outlined below.1. In cases of respiratory distress, pressure driven artificial respirators are used. A new technique using high frequency respiration is quite promising, but the pressure distribution in the lung as a function of frequency is not yet known. At these frequencies of 1 to 60 Hz, the lung expands asynchronously (2) and a better understanding of these expansion nonunlformltles could provide valuable Information about the mechanics of high frequency ventilation.2. Listening to the sounds In the lung can yield valuable Information about the state of the lung. To improve the technique, a better understanding of how acoustic waves propagate through the lung is needed.3. The response of the lung as It Is subjected to acoustic excitation, dynamic loading or shock waves is not well understood. A better knowledge of these responees can lead to improved treatment for patients subjected to either explosive pressure waves or car crashes.4. Researchers are measuring the acoustic Impedance of the Iung to detect early states of dysfunction. Sneckenberger and Whitmoyer (3) have reported Impedances obtained at acoustic frequencies up to about 6000 Hz. However, It la not certain which parts of the lung are responding to the acoustic excitation.To Investigate the vibratory characteristics of the lung, excised rat lungs were excited via the trachea with acoustic waves at frequencies up to 6000 Hz. Thie paper describes an Instrumentation system, utlllzlng time-averaged holographic Interferometry, to detect and quantify the response of the lung surface to the acoustic excitation."

Jan 1, 1989