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By R. L. Templin

In treating a cast metal by any working process such as rolling, drawing or forging, variations in the conditions present in the remelting, casting, chilling and preheating of the initial ingot will certainly have some effect on the physical properties of the final product. In considering the effects of cold working on the physical properties of metals, however, it will be assumed that these factors, being controlled according to best practice, will remain constant and therefore may be neglected. Starting with such a uniform metal ingot, the next operation in the production of wrought metal involves hot working by rolling, forging or extrusion so as to produce a slab, billet or bloom. This working must be sufficient to produce substantial grain refinement and minimize any defects occurring in the initial ingot. Even such a hot-worked product is not suitable as a starting material for determining the effects of cold working because it contains internal strains analogous to those resulting from cold working. It is necessary, therefore, to supplement the hot working with a considerable amount of cold working, followed by a proper annealing in order to obtain a material suitable for use in defining the effects of cold working on the physical properties of a metal. That is, if the effects of cold working are to be evaluated accurately it is necessary to have other effects at least constant if not absent. Such material, unfortunately, cannot always be obtained in commercial practice but the requirements just indicated certainly represent the desired goal; this goal has been attained in the treatment of some metals, one being aluminum. Factors That Must Be Considered Simultaneously with Cold Working So many other factors affect the physical properties of a metal that it is necessary to consider these factors simultaneously with cold working; their effects vary in magnitude with the amount of cold work present. The most important of these factors are: (I) chemical composition, (2) structure, (3) temperature of working, (4) character of working, (5) rate of working, and (6) methods used for measuring results. For

Jan 1, 1930

By D S. Preece

The aim of the present work is to investigate the effects of shooting multiple explosive charges, in the same borehole, on the amplitude and frequency content of the generated seismic wave. The work also investigates the effect of the coupling medium used in the borehole on the quality of the generated seismic wave. The delay period between the shots is on the order of months and up to a year. The investigation utilizes a numerical modeling approach which is capable of modeling the detonation of explosives as well as shock and stress wave propagation in solids.

Jan 1, 2012

By Prof. Dr. T. R. Boulos

The Egyptian marine phosphorite of Sebaiya West, the Nile Valley, consisting of both non-oxidized hard siliceous and oxidized leached friable ore types, is subjected to a roughing-cleaning silica flotation circuit for production of wet-process phosphoric acid concentrate. Operating at its maximum capacity of 268 t/hr, the following were the main problems encountered during the early stages of running the plant: 1. The tremendous amount of slimes generated by scrubbing the crushed ore causing turbidity in the plant thickener after a short time of operation, regardless of the added flocculant. 2. Rod mill choking leading to inefficient performance of all other equipment and poor flotation results. 3. The drastic increase in imported oleic acid price. Pulp density and slurry flowrate measurements at different points of the plant as well as ore microscopy, size distribution analysis, chemical analysis and x-ray diffraction analysis of representative ore samples coupled with Work Index measurements of feed samples showed that the wide variation in the ore's hardness was responsible for such problems. Application of the locally produced non-edible rice bran oil as a substitute to imported oleic acid in flotation resulted in total saving of U.S.$2 million in 1990. The total unsaturated fatty acid content of the oil is high, ranging from 75.2 to 81.5 mole % of which the C18-unsaturated fatty acid content ranges from 72 to 79 mole %.

Jan 1, 1993

By Mallett CW, Hammond RL

Geological maps of the Pacific Rim recently published by the Circum-Pacific Council for Energy and Mineral Resources have provided a useful perspective from which to view modern plate interaction and the evolution of modern fold belts. An important lesson from any study of modern plate interaction is that of the normality of change. The chaotic is more usual than the simple. Present day convergent margins with mixed characteristics are measures of this chaos. Indeed, the character of less than one third of the present length of the Pacific Rim can be ascribed to conventional models of plate interaction. Another lesson is that of the great mobility of oceanic crust. Enormous areas of the Pacific may not be represented in future fold belts developed at convergent boundaries unless normal consumption processes are disrupted, and even then only by linear zones a few kilometres wide. The axes of divergent boundaries creating Pacific Ocean crust have been equally mobile, with new spreading sites taking over from older sites through time. Divergent boundaries, whether active or inactive, consist of oceanic crust, and may be wholly consumed at collision sites with convergent boundaries. Their only potential contributions to fold belt evolution are transforms and magmatic activity. It is this transform component that can provide us with a mechanism to explain the apparent contradiction of both compressional and extensional features occurring together in a developing fold belt. Reconstructions for the SW Pacific are used to demonstrate that the fold belts under construction during the last 4% (Jurassic- Recent) of geologic time have involved interaction between convergent, divergent, and transform boundaries. In the last 15% of earth history (Late Proterozoic-Recent), many enigmatic features of the geologic landscape in Eastern

Jan 1, 1987

By V. E. McKelvey

Some understanding of the United States mineral resource potential is essential for planning and policy making for the future. Reserves of some minerals are essentially lacking and for many others they are sufficient for only short term needs. Estimates of undiscovered resources of many minerals are substantial but are insufficient to support long term requirements, particularly if they continue to increase as they have in the past. Presently, subeconomic resources of some minerals such as aluminum are huge, but their recovery may require increased amounts of energy, which poses problems both as to cost and availability. Beyond these identifiable components of the United States mineral potential, what are the prospects? If they could be identified specifically, of course, they would be included in the above. An unappraised potential of new production and discovery can be expected to exist in known districts, where unproved methods of exploration may yield new discoveries; in new types of ore deposits; in metallogenic provinces as yet unrecognized or poorly explored; in frontier areas and in deeper parts of the crust as yet unexplored; and in presently subeconomic sources that may come within economic reach as the result of technologic advance. Other sources may extend the life of domestic material supplies -- substitution of abundant for scarce materials, recycling and prevention of waste, improved efficiency in recovery and use, and conservation of use.

Jan 1, 1976

By James D. Hervol, Josepph W. III Leonard, Barbara J. Arnold

INTRODUCTION Dry concentration or pneumatic cleaning uses air currents as the separating medium. Pneumatic cleaning in the United States today is limited to three or four operations. In fact, the quantity of bituminous coal cleaned pneumatically has declined from its peak in 1965 of about 25.4 million tons (23.1 Mt) to its current level (1988) of less than 4 million tons (3.64 Mt) annually, as shown in Fig. 7-9 1. In 1940, pneumatic methods accounted for 15% of the bituminous coal and lignite cleaned in the United States as given in Table 7-32. Currently, pneumatic methods account for less than 2%. The largest air plant was built in Pennsylvania about 1968 with 14 units processing 1400 tph (1280 t/h) of 3/, in. X 0 (19 mm X 0) raw feed and two additional units retreating middlings. This same plant is one of only three or four plants still operating air-cleaning devices in the US. A wet plant was added in 1985 to increase the efficiency of cleaning the fines. The air plant is still used as a scalping operation for the coarse material. Five additional operations are either no longer in production or have discontinued the use of air tables within the last year. Wet cleaning methods are now being employed at the facilities that have discontinued air table operation. he advantage of dry cleaning techniques is the low moisture content of the clean coal product. However, to decrease respirable dust, mining operations must use water sprays on modem mining equipment. This water adds to the moisture content of the run-of-mine coal and decreases the effectiveness of dry cleaning processes that rely on low surface moistures in the feed to allow for good separations. Wet cleaning methods are preferred, especially since they also allow for much sharper separations. The advantage of dry cleaning techniques is the low moisture content of the clean coal product. However, to decrease respirable dust, mining operations must use water sprays on modem mining equipment. This water adds to the moisture content of the run-of-mine coal and decreases the effectiveness of dry cleaning processes that rely on low surface moistures in the feed to allow for good separations. Wet cleaning methods are preferred, especially since they also allow for much sharper separations. Despite dry concentration's drawbacks, research has continued into dry concentrating methods, including both electrostatic and magnetic separation techniques. The real application for future dry cleaning processes is probably at the power plant between the pulverizer and the boiler feed where particles are already dry and ground to fine sizes (- 200 mesh [ -0.075 mm]), increasing the effectiveness of the separation and also, possibly, increasing the liberation of clean coal from finely disseminated impurities. From a utility's viewpoint, pneumatic cleaning offers the best delivered Btu cost, based on the premise that a percent of moisture is just as detrimental as a percent of ash. Additionally, several other advantages are inherent in dry concentration techniques. The main advantage is that dry concentration re-

Jan 1, 1991

By Jeffrey W. Lin, Jonathan D. Abbott, Patrick R. Bowden, Tyson J. Plitt

Pentolite is a class of high explosives containing trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN) with PETN content typically ranging from 40 to 60 wt%. Manufacture involves melting TNT, 80 °C, followed by addition of PETN and trace ingredients to form a homogeneous mixture. Once a mix is ready to be poured, several factors can influence the behavior of the finished product including how long the mix has been at temperature and cooling rate. After the manufacturing process has been completed, storage conditions combined with manufacturing conditions may cause physical changes. Two such changes explored were exudation, liquid exuding from solid boosters, and ratchet growth, irreversible volumetric expansion. Exudation is principally caused by excess water in the process. Ratchet growth is a common phenomenon of nitroaromatic compounds such as TNT where time and temperature fluctuations can cause materials to increase volume, simultaneously decreasing density. Although neither phenomenon affects common attributes such as sensitivity, performance, and shelf-life, both can cause issues in storage and handling. In this study pentolite was cast into various forms under different manufacturing conditions and evaluated over several months of controlled storage conditions including ambient, temperature cycling and elevated isothermal. Subjective and objective measurements were made throughout the evaluation period with the aim to determine the preferred storage methodology.

Jan 21, 2025

By Elizabeth Anne Semon

The marketability of a large volume bulk material is significantly effected by transportation costs. Hence, it is essential for anyone that deals with minerals or mineral wastes to be able to reliably estimate bulk transport costs. The three types of bulk overland transportation modes that will be discussed are truck, railroad, and pipeline. Contract and private carriage are the two types of truck transport generally suitable for movement of bulk commodities. Contract carriers are those transportation firms that service a limited number of shippers and geographic points, and carry a restricted number of commodities. Private carriage consists of control over drivers and equipment by the shipper, ownership or lease of the transport equipment, and shipment of commodities related to the primary business of the shipper.1 A combination of private and contract carriage may also be used. Depending on the size and regularity of the shipment, rail offers single car, multiple car, or unit train service to move bulk minerals. Both long and short distance pipeline transportation has been shown economically and technically feasible for many different solids such as, mine and quarry products, coal, chemicals, copper concentrates, phosphate rock, and sewage sludge. 2

Jan 1, 1973

By F. C. Gennari, D. M. Pasquevich

With the gradual exhaustion of natural rutile, there has been extensive research into its synthesising from lower-grade titanium minerals. The removal of Fe from pseudobrookite (Fe2TiO5) by chlorination was studied, using both isothermal and non-isothermal thermogravimetric measurements. Correlation of the results obtained from element distribution maps, scanning electron microscopy, energy-dispersive X-ray analysis and phases detected by X-ray diffraction in the chlorinated samples showed clearly two associated processes. First, the pseudobrookite particles reacted with chlorine and iron was removed selectively as FeCl3(g), leaving a solid residue rich in the TiO2 phases anatile and rutile, separated from an inner layer of unreacted pseudobrookite by a distinct interphase boundary. Second, chlorine allowed TiCl4(g) to form in the reaction bed, where it removed iron from the Fe2O3 crystals as FeCl3(g) and substituted Ti through a pseudomorphic reaction

Jun 21, 1905

By R Saha, D Barry, C Mawdesley, O Bertoli

Kriged estimates are not typically calculated on blocks substantially smaller than the sample spacing (eg the Standard Mining Unit or SMU). Moreover, the sample spacing for quality variables is often much greater than the SMU size. For short to medium term planning decisions, the shorter term variability in the quality variables is a key economic consideration in defining, setting and meeting coal product specifications.Global uncertainties can be calculated using Drill Hole Spacing Analyses (DHSA). However, knowing the precision of a variable for a one or two year production volume is usually not adequate for variables with low spatial continuity that may fluctuate significantly over daily, weekly, SMU, or shipment volumes.Is there a feasible, reasonable and valid geostatistical method to model the uncertainty of coal quality variables on blocks substantially smaller than the drill spacing (say on the SMU)?The validity of using co-kriging variances, calculated on SMUs to characterise local uncertainty, was tested using a suite of conditional simulations generated for several quality variables for BHP’s Blackwater operation. The conditional simulation results were used as a benchmark against which the results derived from the kriging variances could be compared.The agreement between the kriging and simulation methods for thickness is excellent, with much closer correlations than for the quality variables. Typically, the kriging variances give very reasonable approximations to the simulation-based uncertainties, although there could be some systematic discrepancies which may become much more critical if a classification is to be based on a thresholding of the SMUs relative uncertainties.CITATION:Mawdesley, C, Barry, D, Bertoli, O and Saha, R, 2017. Local uncertainty benchmarking – a coal case study, in Proceedings Tenth International Mining Geology Conference 2017, pp 43–50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By W. H. Ashby, R. W. Cassingham, C. R. Blomberg, J. B. Justins

The Brookhaven field is one of several Basal Tuscaloosa reservoirs located in south-central Mississippi. It is a standstone reservoir, of erratic deposition and with several faults, having an approximate subsea depth of 9,800 ft. A large variation in permeability exists with a weighted average being 256 md. Estimated average interstitial water saturation is 45 per cent. The undersaturated reservoir fluid exhibits marked differences in physical properties with measured saturation pressures ranging from 733 to 2,255 psi. Early rapid decline in reservoir pressure caused the operating interests to unitize the field and initiate a program of pressure maintenance by gas injection. At the time gas injection was commenced, the reservoir pressure had fallen to nearly half of the original pressure with only 4.5 Per cent of the original oil in place produced. The reservoir pressure has since been maintained at approximately 2,750 psig, and cumulative production to date is 17 per cent of original oil in place. An analysis of field performance during gas injection is presented in detail. The program of pressure maintenance by gas injection is considered to be a success, since the expected ultimate recovery has been increased and the current production rate is in excess of 2 per cent of original oil in place per year. Performance has been better, anticipated ultimate recovery is larger, and total production costs are lower than for a similar Basal Tuscaloosa reservoir nearby, even though that field appears to have a more effective natural water drive. INTRODUCTION The history of the Brookhaven Unit is a testimonial for unitization and for the application of engineering techniques in the operation of an oil field. The operating and royalty interests in this field have mutually benefited from their early recognition of the need for unitization and pressure maintenance and from the forthright manner in which these were accomplished. The tangible benefits accruing to the participants in the Unit are: (1) income from gasoline plant products, (2) reduced lifting and operating costs from those of competitive operation, (3) maintenance of high levels of current income by mitigation of the inevitable decline in production rates inherent to natural depletion, (4) an increase in ultimate recovery of about 40 per cent over natural depletion operations. This paper should properly be considered a progress report; however, the performance of the field after five years of pressure maintenance clearly indicates that the ultimate success of the project is assured. LOCATION AND GEOLOGY The Brookhaven field is located in south-central Mississippi, about six miles from the town of Brookhaven. Production at Brookhaven

Jan 1, 1955

By J. A. Finch, A. M. Elmahdy

Blending frothers is becoming common in flotation practice apparently enhancing performance. However, there have been no studies to understand the blend mechanism. In this paper, the effect of two frother blends ofF150 (polyglycol) with MIBC or pentanol (both alcohols) on bubble size, gas holdup and froth height is reported. The blends focused on a small addition of the polyglycol to the alcohols as base frother. The tests showed that the bubble size at blend concentration below the critical coalescence concentration (CCC) of the base frother was decreased but was significantly larger above the base CCC. Froth build-up showed a strong synergistic effect.

Jan 1, 2009

By Cuff C, Taylor RG, Georgees C

Mineralisation adjacent to Herberton occurs within three main subcentres. The Her- berton Hill subcentre is characterised by the association of Sn,W the Herberton Dividing Range South subcentre by Sn, and the Herberton Dividing Range North by Cu, As. The relation- ships between the subcentres are discussed in terms of metal distribution, production, deposit types, wall rock alteration and re- lationships with granitoid intrusives. The temporal and three dimensional spatial re- lationships between the centres are uncertain.

Jan 1, 1978

By M. Drozd

Multi-use pad operators require an efficient and economic method to destroy cyanide in their process residues so new material can be stored on the pad and leached. Operators of the dedicated or single-use pads require an effective cyanide destruction method for pad closure. Cyanide destruction can be accomplished by utilizing oxidants such as hydrogen peroxide or calcium hypochlorite, or by utilizing ferrous sulfate which sequesters the cyanide in strong acid dissociable complex. Ferrous sulfate can be the preferred method of cyanide destruction because it is a less costly chemical, reaction rates are almost immediate and unlike oxidants, it can penetrate the total depth of a pile without being destroyed by side reactions. Literature indicates that the (Fe(CN)6)-4 com~lex is produced slowly but it appears that complexes such as Fe(CN)4(H20)2-or Fe(CN)4(OH)2)-4, are formed quickly and should have no U.V. sensitifity, unlike (Fe(CN)6)-4. Stoichiometry of the testwork indicates that Fe«CN)4(OH)2)-4 complex may be the species formed. The usage of ferrous sulfate has the advantage of being able to bring ~ level down that divalent metal ions such as Cu++, Cd++, Hg++, Pb++ and Zn will form insoluble complexes and precipitate from solutions does not destroy weak acid dissolvable complexes and can leave a heavy metal problem behind after cyanide destruction.

Jan 1, 1990

By N. D. L. Burger

Underwind and overwind protection system concepts for mine hoist shafts were developed in conjunction with and for the Safety in Mines Research Advisory Committee (SIMRAC). End-of-wind operation of mine hoists is the most hazardous aspect of mine hoisting, carrying the highest risk of loss of life, injuries to workers and loss of production. Systems operating mechanically and with local actuation were developed. This was done in order to remove the increased risk associated with dependency on remote or external energy and information supply associated with most existing protection systems. The proposed underwind protection system concept absorbs the energy of motion of a conveyance overrunning the design lower limit of travel by drawing a metal strip through a set of rollers. This action causes dynamic cyclic plastic bending of the strip material that converts the kinetic and potential energy of the conveyance into strain energy of the metal. In the concept design a pair of steel wire rope slings attached to the strips catch the overrunning conveyance and transfer the retardation force. The proposed overwind protection system concept absorbs the energy of motion of a conveyance overrunning the design upper limit of travel by early detaching of the conveyance from the hoist rope. This detaching is carried out via an additional detaching hook activation mechanism fitted at a sufficient height below the spectacle plate to allow the conveyance to retard to standstill under gravity before it would crash into the spectacle plate. The conveyance so brought to rest is prevented from falling by means of jack catches on the conveyance interacting with a rack (toothed profile) fitted on the guide rails in the retardation zone. Scale models (1:10 scale) of both protection systems were designed to conform to established retardation standards. The retardation standards were limited by the requirement of passenger safety in retarding cages. The models were then built and tested in a1:10 scale shaft model. Retardation performance close to the required levels was achieved. The retardation distance required should allow such systems to be retrofitted in most existing shafts. Given the simplicity and robustness of the designs, further development was recommended because of their enhanced self-sufficiency and reduced risk of malfunction. Keywords: underwind, overwind, deceleration, mineshafts, hoisting.

Jan 1, 2004

By P. W. George, G. A. Hellstrand

In 1915, H. A. Guess, Vice President of American Smelting & Refining Co., in charge of its Mining Department, learned that the Anglo-Newfoundland Development Co., Ltd., a pulpwood and paper-mill enterprise, had found upon its large concession in Newfoundland, and had opened up by shaft to the third level and some drifting, a lenticular orebody indicating about 100,000 tons, as an extremely fine-grained sulfide ore, averaging about 0.05 oz. Au, 4 oz. Ag, 1.5 per cent Cu, 10 per cent Pb, 18 per cent Zn; and that having sent parcels of this ore to Minerals Separation, Ltd., and various other metallurgical testing concerns without obtaining any success in commercial separations thereof, had discontinued work thereon and let the workings fill. Mr. Guess wrote to the general manager of that company and obtained a few hundred pounds of the typical ore, which he sent to his company's metallurgical testing laboratory at Flat River, Mo., outlining various flotation tests desired thereon, in an endeavor to obtain separation into a commercial lead concentrate and a zinc concentrate. But the art of flotation had not then progressed far enough to treat such ore, the galena and zinc blende being so fine grained that grinding to about 300 mesh was required to release the mineral particles in their gangue. Mr. Guess had flotation and other tests continued upon this ore from time to time with whatever new reagents and flotation devices were evolved as time went on, and finally, in 1925, he succeeded in effecting in his company's testing plant, then at Wallace, Idaho, separations into lead concentrates and zinc concentrates of satisfactory commercial grade. Mr. Guess then proceeded to unwater, examine and sample the property and made with the owners a partnership operating agreement upon the mine itself and a considerable area surrounding it, and in the early summer of 1926 began to prospect for additional orebodies, utilizing for such prospecting geophysical methods under the direction of Hans Lundberg, methods which up to that time had been little used in mining in the western hemisphere. This geophysical work found two large flat-lying orebodies of a type precisely similar to the smaller body of the original discovery. The larger orebody, some 3500 ft. west of the original

Jan 1, 1935

By Orson Shepard

TEXTBOOKS on fire assaying list the following standard methods of assaying sulphide ores: (1) scorification, (2) litharge-niter, (3) soda-iron, (4) roasting, (5) combination wet and fire. The litharge-niter method has proved the most satisfactory, and is the usual method for assaying sulphide ores and concentrates. It gives good results when suitably conducted and when lead buttons of uniform size are produced so that the cupellation temperature can be properly controlled. The main objection to the method is the inconvenience of determining the amount of niter to add to each assay charge to produce lead buttons of suitable size from a set of fusions. For the assay of different materials, the niter requirement varies with the particular sulphide minerals present, the amount of sulphide minerals present, the slag composition, and the rate of heating the charge in the furnace. Except for some materials, so uniform in composition that the same amount of niter can be used in assaying all samples, the amount of niter must be determined for each sample to be assayed. This is done by either: (1) calculation from an estimate of the kind and amount of sul-phide minerals present in the sample, or (2) a preliminary fusion. Some assayers use one method and some the other. The estimation method takes the least time; but much experience is required to obtain close estimates on a wide variety of materials. At best, the sizes of the lead buttons obtained vary considerably. The preliminary fusion method usually gives lead buttons of fairly uniform size, although sometimes there is a variation because the oxidizing power of niter varies a little with the charge. This variation can be eliminated by two preliminary fusions: one to determine the reducing power of the ore, and the other to determine the oxidizing power of niter in the charge. The objection to the prelimi-nary fusion is the extra time and expense involved.

Jan 1, 1939

By G. A. Hellstrand

IN 1915, H. A. Guess, Vice President of American Smelting & Refining Co., in charge of its Mining Department, learned that the Anglo-New-foundland Development Co., Ltd., a pulpwood and paper-mill enterprise, had found upon its large concession in Newfoundland, and had opened up by shaft to the third level and some drifting, a lenticular orebody indicat-ing about 100,000 tons, as an extremely fine-grained sulfide ore, averaging about 0.05 oz. Au, 4 oz. Ag, 1.5 per cent Cu, 10 per cent Pb, 18 per cent Zn; and that having sent parcels of this ore to Minerals Separation, Ltd., and various other metallurgical testing concerns without obtaining any success in commercial separations thereon, had discontinued work thereon and let the workings fill. Mr. Guess wrote to the general manager of that company and obtained a few hundred pounds of the typical ore, which he sent to his company's metallurgical testing laboratory at Flat River, Mo., outlining various flotation tests desired thereon, in an endeavor to obtain separation into a commercial lead concentrate and a zinc concentrate. But the art of flotation had not then progressed far enough to treat such ore, the galena and zinc blende being so fine grained that grinding to about 300 mesh was required to release the mineral particles in their gangue. Mr. Guess had flotation and other tests continued upon this ore from time to time with whatever new reagents and flotation devices were evolved as time went on, and finally, in 1925, he succeeded in effecting in his company's testing plant, then at Wallace, Idaho, separations into lead concentrates and zinc concentrates of satisfactory commercial grade. Mr. Guess then proceeded to unwater, examine and sample the property and made with the owners a partnership operating agreement upon the mine itself and a considerable area surrounding it, and in the early summer of 1926 began to prospect for additional orebodies, utilizing for such prospecting geophysical methods, under the direction of Hans Lundberg, methods which up to that time had been little used in mining in the western hemisphere.. This geophysical work found two large flat-lying orebodies of a type precisely similar to the smaller body of the original discovery. The larger orebody, some 3500 ft. west of the original

Jan 1, 1934

By Walter D. Holland

This instructors guide is intended for use in a course which teaches metal and non-metal mine inspectors to perform surveys for inhalation contaminants in above ground metal and nonmetal mine work areas. The handbook entitled "Handbook for Surveys of Inhalation Contaminants in Above Ground Metal and Nonmetal Mining and Processing Work Areas? is used as a manual during the course. The manual contains a survey check list, rules for determining if sampling is required, a list of most frequently encountered contaminants, a list of candidate contaminants and their sampling conditions, and a description of control procedures and devices. There are several experiments in this guidebook which the trainees perform to acquaint them with the sampling systems.

Jan 1, 2011

By W. B. Boggs

A paper describing the Noranda smelter was presented at the 1930 annual meeting of the Institute (1). A lacer article appeared in the Trans-actions of the A.I.M.&M.E. in 1933. Since that time there have been many changes and improvements in plant operation and it is the abject of this paper to give an account of developments up to the beginning of 1939. The Noranda smelter was built originally for a capacity of 30,000 tons a month. At present, the average tonnage being treated is 110,000 tons a month, the tonnage of custom ores alone amounting to almost the total rated capacity of the original plant. This increase has been accomplished by increasing the capacity of the reverberatory furnaces from 700 tons of solid charge per furnace day in 1928 to 1,500 tons per day at the present time. In 1935, it appeared chat the limit of furnace capacity had been reached at about 1,300 tons of charge per day because of the short life of the sprung silica arches. However, the adoption of the suspended magnesite roof, which had been developed at the Flin Flou smelter of the Hudson Bay Mining and Smelting Company, overcame this difficulty and it is believed that the limit of the capacity of the present reverberarory furnaces has not been reached. A brief account of the changes to equipment in the various departments will be given, followed by a description of the more important features of present smelter practice.

Jan 1, 1939