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By B. E. Davis

The Bureau of Mines conducted tests on samples of two Florida phosphate slimes t6 devise a technique to recover phosphate currently dis-carded because of its fine size. A flotation technique was devised to recover the phosphate contained in two fractions of each slime: the plus 37um fraction and the plus 20-um fraction. The technique involved conditioning the flotation feed with sodium silicate and a fatty acid-fuel oil emulsion, floating a rougher phosphate concentrate, and cleaning the concentrate in two cleaner stages with sodium silicate added to each for gangue depression. Concentrates containing 21.0 to 32.3 pct P20S were produced with recoveries of 68.1 to 84.2 pct of the P20S con-tained in the flotation feed.

Jan 1, 1987

By Toshiki Kabutomori

In fuel cell powered automobiles, hydrogen is required to be stored in materials that have a hydrogen storage density of over 4 mass%; further, these materials should be capable of supplying hydrogen by using the waste heat from a fuel cell, which is at a temperature of 373 K, in order to match the mileage of gasoline-powered vehicles. A Ti-Cr-V alloy, which exhibits a BCC structure and forms a solid solution, is a promising candidate for onboard hydrogen storage materials. Although it has a large hydrogen storage capacity of over 3.9 mass%, the rechargeable hydrogen capacity is limited to approximately 2.6 mass%. In this study, the effects of fine pulverization of the alloy on PCT (hydrogen pressure-composition-isotherm) characteristics were investigated in order to improve the rechargeable hydrogen storage capacity of the alloy. From the PCT measurements of the finely pulverized samples of the alloy, a plateau in the absorption curve was observed to begin at a hydrogen concentration of 0.5 mass%; further, a rechargeable hydrogen storage capacity of 3.3 mass% was obtained. This was greater than that obtained from the sample that was not finely pulverized, i.e., 2.5 mass%. However, the plateau width in the desorption curve was 2.5 mass%, which was the same as that observed for the sample that was not finely pulverized. The increase in the rechargeable hydrogen capacity during absorption is attributed to the precipitation of the -hydride phase (MH~2) directly from the metal phase (phase). The precipitation of the phase (MH~0.5), which should be formed in low hydrogen concentrations, is suppressed as a result of a possible reduction in the internal defects such as dislocations, vacancies, and grain boundaries by fine pulverization and annealing of the alloy.

Jan 1, 2006

By R Wei, Y Peng, D Seaman

This study addresses a widespread problem confronting the mining industry: the deleterious effect of clay minerals in flotation. This problem is seemingly exacerbated by the presence of iron contamination from grinding media. The interaction of clay minerals and grinding media in copper and gold flotation was investigated in this study. A low-clay ore and a high-clay ore were obtained from Telfer to represent different contents of clay minerals, while stainless steel and mild steel grinding rods were used to produce different grinding chemistry, in particular, iron contamination. Flotation tests on an unsized and sized basis were conducted to reveal how clay minerals and grinding media affect copper and gold flotation. Iron contamination and the oxidation of copper minerals were quantified by ethylene diamine-tetra acetic acid (EDTA) extraction. It is interesting to find that both clay minerals and iron contamination depressed the flotation primarily in fine particles smaller than 33 ¦m, and clay minerals played a dominant role. Although flotation of coarser particles greater than 33 ¦m was less affected by clay minerals and iron contamination, coarser grinding to increase P80 was not an effective way to improve copper and gold flotation for the high-clay ore. This study suggests that to improve copper and gold flotation from clay ores, clay dispersion in conjunction with the minimisation of iron contamination may be required.CITATION:Wei, R, Peng, Y and Seaman, D, 2013. The effect of grinding media on copper and gold flotation in the presence of clay minerals, in Proceedings World Gold 2013 , pp 283-288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By R. P. Fischer

The Colorado Plateau region has been the principal domestic source of uranium, vanadium, and radium. The value of these commodities produced from the region through 1964 slightly exceeds $2 billion. Most of the deposits occur in streamlaid lenses of sandstone in the Chinle and Morrison Formations. The ore minerals below the zone of oxidation are low-valent oxides and silicates of uranium and vanadium; all of these, except the quite stable vanadium silicates, oxidize readily to a variety of high-valent uranium and vanadium minerals. The ore minerals partly replace fossil wood but mainly impregnate sandstone, typically forming tabular ore bodies that are nearly concordant to the bedding of the host rock. The deposits range in size from those containing only a few tons of ore to those containing more than 1 million tons. Stratigraphic, lithologic, and sedimentary structural factors obviously influenced the localization of these deposits, but igneous activity, hydrothermal mineralization, and tectonic structures show no similarly consistent influence on localization. The deposits are epigenetic, but the source of the ore metals, the nature of the ore-bearing solutions, and the time of ore emplacement are uncertain. A few uranium deposits in the region are dominantly discordant to bedding and occur in collapsed breccia pipes or along linear fractures. Their origins are also uncertain.

Jan 1, 1968

By Euler De Souza, J. Daniel Stinnette, Julian Varaschin

"This paper outlines some of the factors that affect the airflow required for the ventilation of modern diesel-powered equipment and of electric equipment and examines how they can be applied in determining reasonable ventilation rates for Tier IV compliant diesel equipment and for electric equipment operating in mining environments. Airflow calculations for modern diesel-powered equipment and for electric equipment are more complex and must be based on a combination of factors that are unique to each mine. Methodologies for ventilation rate determinations for each case are proposed in this paper.INTRODUCTIONTraditionally, airflow requirements for production and support equipment operating in underground mines have been determined by multiplying the vehicle power by a ventilation rate that was either mandated by regulations or determined empirically from known quantities. However, in light of the drastic reductions to diesel equipment emissions mandated by the US EPA Tier IV and EURO Stage 4 regulations, there is still a great deal of uncertainty in the underground mining industry among those responsible for the ventilation of planned new mines or the expansion of current mines. The question remains, what ventilation rates should the ventilation system designer apply for modern diesel equipment?Also, given the ongoing development of grid/battery-electric equipment and active construction of fully electric mines, it has become critical to determine adequate airflow rates per brake kilowatt of electric engine power. One of the most important criteria for determining ventilation rates for electric equipment is the amount of heat they generate, as this is the most significant emission produced by electric equipment (which do not produce exhaust gases or particulates). Therefore, ventilation rates required to dissipate heat from electric equipment must be suitably determined for all electric vehicle fleets operating in underground mines."

Jan 1, 2019

By Willard C. Lacy

INTRODUCTION A program to insure adequate talent for development and management of our mineral resources entails two equally important and interrelated aspects: 1) attracting and retaining promising student talent, and 2) providing a first-rate education for those entering careers in mineral science and engineering. Manpower shortages have eased in many areas of engineering, particularly in those areas dependent directly or indirectly upon government contracts in space and war programs. However, in the minerals industry the needs still remain critical. As increasing concern over preservation of the environment has developed, the political and social reaction was to seek out major offenders, to look for "whipping boys" -- and the mineral industry was, and had been, an offender. It was there for everyone to take pictures, it couldn't be covered up, and the Department of the Interior lashed away in the beautiful and popular brochures: Quest for Quality, The Third Wave, The Population Challenge, and Surface Mining and Our Environment (Ravaged Land). The Sierra Club, the Field and Stream magazine, TV, and daily news media added their lashes. In the minds of our social-conscious youth the mineral industry took on the image of "exploiters" of natural resources; "polluters" of streams, lakes, and the atmosphere; "despoilers" of wilderness areas and scenic beauty -- a plague to combat, rather than an exciting challenge that entailed exploration of the remote, conquering of the primitive, and developing of the undeveloped. Enrollments declined and many traditional mineral engineering curricula were abolished or Integrated into other stronger engineering departments to meet student-faculty ratio requirements.

Jan 1, 1971

By J S. Laskowski

Froth flotation process requires the use of frothers. These important flotation agents are commonly characterised as either æselectiveÆ or æpowerfulÆ and are chosen following general guidelines and verification by laboratory and/or pilot plant tests. Fundamental properties of the flotation frothers have been extensively studied over the last few years. These studies have led to the development of standardised procedures to characterise frothers in terms of their ability to reduce bubble size and to increase foam stability. In this research project, the performance of five frothers in flotation of coal is evaluated and related to the fundamental properties of these agents. Since the recovery of water in the concentrate is closely related to the non-selective transport of solid particles by entrainment, the tested frothers are also assessed in terms of their ability to promote the transport of water towards the froth collection zone, both in absence and in presence of solids.

Jan 1, 2005

By Sunil G. Warrier

A rapid infrared forming technique has been developed to fabricate titanium matrix composites. This technique applies infrared heating to infiltrate titanium alloys into carbon and silicon carbide prepregs. The entire process typically takes 1-2 minutes in an inert atmosphere. The advantages of this technique are that the process is fast, simple, does not require a vacuum or a high external pressure. The process is very economical both in energy conservation and operation costs. This technique has been used to produce void free composites with limited, well controlled fiber-matrix reactions and mechanical properties comparable to currently available titanium matrix composites.

Jan 1, 1993

By C. Moctezuma

Since the start up of the IMMSA electrolytic zinc refinery in 1982, the dissolved iron coming from the acid attack of the ferrites has been precipitated by the jarosite process. At the beginning of operations, sodium jarosite was produced; however, the plant was converted to ammonium jarosite in 1990. The final storage of the residue is on the company&apos;s property adjacent to the plant, over the natural surface of the land. Before the construction of the refinery, several studies were done in order to evaluate the characteristics of the ground, such as, permeability, underground water localization, etc. The results showed that the site was adequate for the storage of this kind of material. For several years, the jarosite residue was filtered on rotary drum filters and was sent as a pulp to the storage area for settling. The water from the storage pond was recycled to the re-pulp tank for the jarosite residue. These filters were replaced in 1999 by an automated filter press. Since then, the jarosite residue has had a lower water content, and the zinc recovery improved. At present, a second filter press for the jarosite circuit is in the acquisition process to diminish the soluble zinc content in the residue from the present value of 2% to < 1% Zn.

Jan 1, 2006

By S. Plaatjie, L. Linzer, M. S. D. Manzi, M. Sihoyiya

Fiber-Optic Sensing and UAV-Platform Techniques for Innovative Mineral Exploration (FUTURE) is a joint European Union and South African consortium project funded under ERA-NET Cofund ERA-MIN3. The project aims to develop cost-effective and novel seismic methods to image geological structures ahead of the mine face, ultimately leading to improved decision-making and safer mining practices. In this study we present results from numerical simulations conducted at South Deep Gold Mine for active in-mine seismic surveys. The study uses a finite differencing code known as WAVE3D, which models models the propagation of a seismic wave generated by stress pertubations that are applied to a defined grid. The numerical simulation model included two major ore bodies (Black Reef and Ventersdorp Contact Reef) and mine tunnels. The model was constrained using laboratory physical property measurements from underground borehole samples such as seismic velocities (e.g., compressional and shear waves) and bulk densities. Two case studies were created, one modelled the active shots and receivers on surface, and the other modelled the shots at depth (in a mine tunnel at ~4000 m depth) with receivers on surface. In both cases, the objective was to investigate the wavefield propagation through the rockmass between the mine tunnel and surface. The simulated wavefield produced by the source located along the mine tunnel was successfully recorded on surface. The surface-recorded wavefield exhibits clear one-way P-wave arrival times at approximately 450 ms to 500 ms, which can be used to calculate the surface-tunnel P-wave refraction tomogram. The results from the study were used to constrain the design, and for the acquisition and processing of the real surface and in-mine seismic surveys acquired under the FUTURE project.

Jan 12, 2025

"This model specification includes sample text shown in normal font with commentary in italics. The commentary is intended to highlight project-specific items the specification writer should consider during development of the specification. In some sections, typical values are presented to indicate common practice, and these values may be changed to reflect projectspecific requirements. The commentary should be removed before using the specification for a project.1. SCOPEThe work consists of designing, furnishing, installing, post-tensioning and testing helical anchors used to support tension loads, and any ancillary materials (e.g., load transfer devices, etc.) according to the project plans provided and these specifications. Unless otherwise noted, the installing contractor shall provide all labor, tools, equipment, and materials necessary to accomplish the work. The parties referred to in this specification are as follows:• The Owner is the property owner.• The Owner’s representative is the individual or firm hired by the Owner to execute project tasks required for the successful design and construction of the overall project. Tasks could include construction management, design, oversight, etc.• The anchor designer is the individual or firm generally hired by the installing contractor to design the helical anchors.• Installing contractor installs and tests (if necessary) the helical anchors, and possibly other tasks associated with the project.It is important to clearly define the roles and responsibilities of every party on each project to promote good communication and reduce potential for contractual misunderstandings. Different types of contractual vehicles (design-build, value engineering, etc.) require different roles and responsibilities for the various parties, which should be considered in specification development.The Owner will provide suitable access to the construction site for the installing contractor’s personnel and equipment. Unless specifically noted otherwise in the contract documents, the Owner will remove and replace any structures, utilities, pavements, landscaping or other surficial improvements in the work area as necessary to facilitate the work. The Owner will be responsible for overall construction oversight to minimize potential for developing unsafe conditions. The work may include post-construction monitoring of anchor performance if required by the Owner or the anchor designer to confirm performance of the anchors subsequent to their installation. The work may also include installation of additional anchors if the initial installation does not meet specified capacity or performance requirements. Responsibility for providing subsurface investigation shall be addressed in the bid documents. The Owner is responsible for providing to the installing contractor all available subsurface soils, rock and groundwater information and geotechnical testing data."

Jan 1, 2016

By Magella Pelletier

"IntroductionDepuis une vingtaine d&apos;année, les nombreux travaux de géochimie effectués par l&apos;industrie privée et les milieux gouvemementaux ont permis:• de découvrir de nombreuses zones minéralisées a valeur économique;• d&apos;identifier et de vérifier certains patrons de dispersion géochimique au-dessu s de secteurs minéralises déjà connus;• de favoriser le développernent des techniques analytiques;• de forcer le développement d&apos;une mise en carte des résultats d&apos;analyse, qui soit plus adéquat afin de permettre une meilleure interprétation géochimique.L&apos;une de ces cartes géochimiques qui permet le mieux de mettre en valeur les données analytiques et qui fut instaurée au debut des années 80, est la carte d&apos;interprétation géochimique par pondération.Cette carte numérique semi-quantitative, qui est construite à partir des données de base et de l&apos;importance des éléments indicateurs pour une substance donnée, permet d&apos;identifier et de définir des zones possédants de fortes probabilités pour la recherché de sources minéralisées."

Jan 1, 1987

By Yanan Zhang, Hongwei Deng, Feng Gao, Bo Ke

Recently, liquid carbon dioxide (L-CO2) blasting technology has attracted attention due to its good fracturing effect and safety performance, especially in coal seam permeability improvement. This paper analyzes the blasting effect of L-CO2 based on experiments and studies the fracturing mechanism from the perspective of stress wave action via theoretical analysis and peridynamic simulations. The results indicate that L-CO2 blasting achieves a good fracturing effect without forming a crush zone, and the loading rate and strength of the stress wave are key factors.

Jan 19, 2022

By M. Fig, B. Treffner, J. Brune, C. Strebinger, G. Bogin, D. Pardonner

"Methane gas explosions in a longwall coal mine can originate from in or around the gob and can seriously harm nearby workers and equipment. In order to fully understand the explosion flame and pressure wave propagation in the mine, it is important to investigate methane flame propagation in confined spaces as well as flame interaction with rock rubble and other mine structures. The latter can lead to enhanced turbulence causing high-speed deflagrations and/or detonations. Researchers ignited methane-air mixtures in horizontal, cylindrical reactors that contained inserts to simulate various gob characteristics. Rock surface topology and ignition location were investigated. Results show rock surface roughness increased fluid motion, thereby increasing methane flame front propagation velocity, overall pressure rise of the explosion, and time of pressure decay. Moving the point of ignition away from the open end of the reactor resulted in an increase in peak overpressure and an overall pressure rise of the explosion. Experiments were used to validate a computational fluid dynamics (CFD) combustion model that will be incorporated into a mine-scale explosion model to simulate and predict explosion hazards of large scale methane gas deflagrations in longwall coal mines. INTRODUCTION Coal mining is an integral part to our global society with coal-fired power plants providing about 40% of our global electricity [1]. A common method of extracting coal underground is by longwall mining. Researchers and investigative reports have found that explosive gas zones of methane-air mixtures can form along the longwall face and within the longwall gob, presenting an explosion risk to nearby workers and equipment [2]. In an explosion, the resulting flame and pressure wave presents a fatal traumatic injury hazard and can cause serious damage to equipment. In order to evaluate and mitigate the explosion risks in longwall coal mining, researchers at the Colorado School of Mines are developing a coupled CFD and combustion model of a longwall coal mine. The purpose of the model will be to better predict the explosion hazards under various mine conditions in order to build stronger prevention and mitigation strategies for miners."

Jan 1, 2018

By M. C. Flemings, F. R. Mollard

Two-phase Pb-Sn alloys, ranging in compositiotz from 12 to 26 at. pct Pb, were unidirectionally solidified in a convection-fvee system, with thermal gradients in the liquid of up to 480°C per cm. Plane front solidification Loas achieved in all alloys at sufficiently steep gradient and slow growth rate. Conditions causing breakdown of the interface to a cellular or dendritic structure were roughly as predicted by a sinlple constitutional supercooling criterion. Structures of alloys of near-eutectic composition, solidified with plane front, exhibited a lamellar structure; the alloys furthest from the eutectic exhibited a rod-like morphology. Assumptions used in a previous paper for calculations of solute redistribution in two-phase plane front growth are shown to be reasonable for Pb-Sn alloys. Results of calculations are in good agveement with experiment. These show that variations in growth rate during solidification of the composite produce marked changes in average composition of the solid. IN a previous paper, Part I,&apos; conditions necessary for plane front solidification of two-phase alloys were discussed and calculations given on solute redistribution in this type of solidification. This paper, Part 11, describes experiments on Pb-Sn alloys, designed to check the assumptions of the analyses presented, and to demonstrate their applicability to a given alloy system (Pb-Sn). APPARATUS AND PROCEDURE General. A vertical crystal growing unit was built for the study as described below, and "normal solidification" employed throughout (i.e., the ingot was completely melted except for a portion near the bottom end and then solidification initiated). The furnace was designed to permit achieving very low interface velocities, and steep gradients, in essential absence of convection; it is sketched in Figs. 1 and 2. Simple heat flow considerations indicated choice of a small-diameter specimen (ingot) to achieve high thermal gradients; ingot size chosen was 0.3 cm in diam. The ingots were held inside silica tubes 0.06 cm wall thickness. The requirement for an essentially convection-free system was met by use of the vertical furnace with the heat source over the heat sink, as well as by use of the small diameter ingots. In addition, by selection of tin-rich Pb-Sn alloys, the diffusion boundary layer (lead-rich) was denser than the bulk liquid and would not cause convection. The only apparent driving force for convection in this system was the small transverse temperature gradient resulting from heat flow into the samples from the furnace. Such convection must have been small, however, since 1) no temperature fluctuations in the melt were noted in the recordings, which would have indicated turbulent convection, and 2) experimental results obtained and described below could not have been achieved in presence of significant convection. Ingot Preparation. Pb-Sn alloys ranging from 12 to 26 at. pct Pb were prepared from high-purity lead and tin (99.9999 pct pure metal). Each alloy was prepared by first melting the pure metals in the proper ratio in air, in a Pyrex container. The melt was then stirred thoroughly with a graphite rod and cast into a preheated graphite mold. Ingots were then prepared from these castings for use in the actual experiments; each ingot consisted of a rod of alloy, 15 cm long in a 25-cm-long transparent fused-silica tube, 0.3 cm ID and 0.06 cm wall thickness. One chromel-alumel thermocouple, made with 0.004-in.-diam wire and protected by a two-hole alumina tube, was inserted into each ingot. The 1.5 cm of the thermocouple nearest the bead were protruding from the alumina tube and were coated with a very thin layer of boron nitride paste which provided electrical insulation while allowing good heat conduction. The electrically welded junction size was about that of each wire and the cross section of the two wires represented about 0.3 pct of the sample cross section. Including the coating, the thermocouple cross section still represented less than 0.5 pct of the ingot cross

Jan 1, 1968

By A M. Garforth

Insurers are hesitant to provide coverage for Open cast Pit side wall collapse, and even the consequent damage to plant and equipment in the pit as well as the resulting interference with the mining operations. After a general introduction to relevant principles of insurance, this paper addresses some of the major reasons for that reluctance based upon the authors? extensive claims experience, examines what limited coverage can still be obtained and looks to the future possibilities. Confidentiality of sources and examples referred to in this presentation is a natural imperative so that a bibliography is not provided but reference is made to relevant sample insurance policy wordings.

Jan 1, 2006

By N. K. Bohidar

Evaluation of the stability of a structure under given boundary conditions requires accurate knowledge of the state of stress as well as the mechanism of failure at the critical state of stress. This paper represents a part of the research done by N. K. Bohidar during 1965-1968 for his Ph. D. research in Mining Engineering at the University of Utah. It summarizes the determination of internal stress and failure phenomena around cylindrical openings in viscoelastic media subjected to lateral restraint and vertical uniaxial load. The conditions of lateral restraint and viscoelastic nature of the media represent conditions associated with subsurface openings in rocks. The financial assistance provided to the project from the University of Utah Research (Uniform School Fund), W. C. Browning Scholarship Fund, Earth Science Research Fund, and D. C. Jackling Loan and Scholarship Fund is gratefully acknowledged. The authors also acknowledge the assistance of S. Siugh, W. Jones, and K. McCarter during the project.

Jan 1, 1970

By J Walshe, G Duclaux, L A. Fisher, R Hough, J S. Cleverley, M F. Gazley

Characterisation of hydrothermal gold systems across multiple scales is increasingly important for our understanding of ore deposit genesis and for targeting new mineralisation. Published work on multiscale mineral system exploration focuses either on applying a single technique across scales or on incorporating a series of techniques across a limited scale range. Typically, these studiesÆ spatial scales vary from crustal to deposit-scale and have successfully linked the distribution and shape of major orebodies to fault systems or varying lithostratigraphy. But, is this scale small enough to answer fundamental questions about the relative timing, processes interactions and mechanisms involved in the formation of ore deposits? We illustrate the potential of a deposit to microscale study, using the Plutonic Gold Mine in Western Australia as an example, to better understand hydrothermal gold systems. Using an integrated approach combining lithological and alteration logs, various geochemical data set, meso- to microscale structural and textural observations and spatial data assimilation, we have revisited the fundamental processes involved in the formation of this significant gold deposit.CITATION:Duclaux, G, Hough, R, Gazley, M F, Fisher, L A, Walshe, J and Cleverley, J S, 2013. A multiscale approach to hydrothermal gold systems - unravelling mineralisation processes at the Plutonic Gold Mine, in Proceedings World Gold 2013 , pp 95-98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

1. ACKERMAN, C. L. The Binary System Manganese-Zinc. Ztschr. Metall., vol. 19, 1927, p. 200. 2. ADKENASY, P., AND KLONOWSKY, S. Über die Manganatschmelze. Ztschr. Elektrochem., vol. 16, 1910, p. 107. 3. AKTIEBOLAGET FERROLEGERINGAR (assignees). Method for the Manufacture of Manganese Alloys Poor in Carbon or Silicon or Else Manganese. British Patent 163262, Apr. 28, 1921; U. S. Patent 1480267, Jan. 8, 1924. 4. Method of Producing Manganese or Manganese Alloys Poor in Carbon or Silicon. British Patent 174923, Jan. 25, 1922.

Jan 1, 1934

By R. Clark Lantz, Charles Stanley, David E. Hinton

Morphometric examination of lung alterations following exposure to toxic and pathogenic substances is invaluable in detecting subtle changes which might otherwise be overlooked. Results, from evaluation of initial structural alterations, support and guide subsequent nonmorphological techniques and, when coupled appropriately, can lead to a better understanding of the pathogenesis of a disease. Morphometry is a technique which can be used to determine, quantitatively, the site, extent, development, and progression of a disease state. Determination of the extent of tissue and cellular involvement in the response to inhalation of silica has been performed in order to gain a better understanding of the development of fibrosis following inhalation of this toxicant. In addition, since silica has been postulated as one of the important pathogenic minerals in coal mine dust' it is important to understand the lung tissue response to silica prior to evaluating the effects of inhaled coal mine dusts. Male Syrian golden hamsters were placed in Hazelton 1000 inhalation chambers and were exposed to either filtered air (controls, n = 24) or filtered air plus 30 mg!m3 silica (Min-U-Si110,95%ofparticles < 5 um,n =24)for16hours per day, five days per week, for two weeks. Animals were returned to the animal quarters prior to subsequent tissue processing at 1, 4, and 12 weeks following exposure. This schedule was designed to allow time for the development of fibrosis. Lungs were fixed by intratracheal perfusion of ½ strength Karnovsky's fixative at a pressure of 20 cm H20 and tissues were taken for embedment and analysis at the light level. Determination of site, extent, and development of alterations was performed using a multitiered approach. Changes in large structures (airways, blood vessels) was determined prior to evaluation of changes at the septal tissue level. Data will be presented outlining the progression of changes. Results indicate the usefulness of morphometric analysis of lungs following inhalation of toxic substances in quantitatively defining the structural alterations.

Mar 1, 1989