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By A. C. Callen

This, report represents the comments of the individual members of the A. I. M. E. Sub-committee on Physics of Mine Ventilation on the proposals of a special committee of the Institution of Mining Engineers (London). As might be expected, there is a certain diversity of opinions, for owing to the shortness of time- it was not possible for the sub-committee to get together for informal discussion. The report is presented in this form in the hope that it will bring out a full discussion by other members in the Institute. OLE SINGSTAD?, New York, N. Y.-The Atkinson formula, P =SV2 K a is quoted and it is stated that this formula is especially applicable to mine galleries but is unwieldy in application, as in many problems the value of K, S and a are assumed not to change. This is the same formula that was used during the preliminary calculations for the ventilation of the Holland Tunnel, and where the above-mentioned values were constant for a number of cases, it was a very simple matter to rewrite the equation n the form P = K1V2 and avoid the repeated use of identical figures. The Atkinson formula assumes 1. That resistance to flow is independent of the pressure. 2. Changes in volume due to change in pressure may be neglected. 3. Changes in density and viscosity may be neglected. 4. That the coefficient K is a constant. 5. That P is proportional to V2. We found, from our experiments in connection with the ventilation of the Holland Tunnel, that all the above assumptions could be safely made, with the exception of No. 3, and No. 4 at, very low velocities. In mine work, where many assumptions must necessarily be made, it would seem inconsistent to attempt to make any allowance for the other factors, which are so small that they can be determined only by the most careful experimental work. However, P does depend directly on the density of the air, and to that extent the Atkinson formula is incomplete.

Jan 2, 1926

By L. F. Mondolfo

R301 is a clad aluminum alloy, composed of a core of a duralumin-type alloy clad with a magnesium silicide alloy. It differs from other well-known clad alloys in that the cladding and the core respond to the same heat-treatments, and therefore the cladding contributes appreciably to the mechanical properties of the material. In Table 1 are reported the compositions of the core and cladding alloy for the material used for the experiments. [ ] In clad aluminum alloys where the core contains copper and the cladding does not, at elevated temperatures the copper tends to diffuse from the core through the cladding. This fact is well known and many investigations have been conducted to determine the features of this diffusion.1-7 Most of those investigations cover materials clad with pure aluminum; the present investigation covers a material clad with an alloy. Since the cladding thickness on R301 varies with the gauge, as shown in Table 2, several gauges were investigated. [ ] MATERIAL AND PROCEDURE The material used was sheet of the following gauges: 0.025, 0.040, 0.064, 0.102, 0.170. Cut in pieces approximately 3 by 5 in., it was in the cold-rolled state and was soaked for increasing times at the following temperatures: 910°F., 940°F., 970°F. A Lindberg cyclone furnace was used for the experiments. The procedure was as follows: The furnace was started empty with controlling pyrometer set at the determined temperature. After the furnace had reached that temperature, it was run for some 20 to 30 min. empty, in order to allow the temperature inside to become stabilized. Then the first samples were introduced. A load thermocouple, with recording pyrometer, was connected with the sample of the heaviest gauge. About 10 min. was required for the material to reach temperature and the soaking time was counted from that point. After 200 min. soaking, the second group of samples was introduced without stopping the furnace. After 200 min. more, the third group of samples was introduced, and so on, until the last sample had been introduced. Every time the furnace was opened and new samples were added, a drop of temperature was registered by the thermocouple connected with the material

Jan 1, 1945

By C. N. Garman

Homestake-New Mexico Partners operate a 750-tpd carbonate leach uranium concentrate mill near Grants, N.M. The highly mineralized water available as process water leaves much to be desired. The 628 ppm as CaCO 3 makes the use of raw water very troublesome in pipes and on filter cloths. However, the residual sodium carbonate in the final filter cake going to tails makes an ideal softening agent. To take advantage of this fact, all makeup water used in the mill is first used as tailing slurry dilution water and comes to the mill from the tailings pond. The 5-acre tailings pond serves as a thickener and 100 to 150 gpm of nearly clear solution is decanted to a pump to be returned to the mill. Since this tailings water has small quantities of uranium in the solution an ion exchange scavenger unit was installed to remove as much uranium as possible. The ion exchange raffinate is then used as final filter wash ahead of the tailings slurrying step. In spite of the large settling area this return water is not clean enough for ion exchange feed. The solids present are very fine and composed of approximately 15 pct (by weight) burnable carbonaceous material common to the sandstone uranium ores in the area, 40 pct SiOz plus 45 pct CaC03. Laboratory work showed that this material responds very well to flotation. Before deciding to use flotation, various clarifying systems such as pressure leaf filters, sand filters, and continuous vacuum pre-coat filters, were considered. Each of these could have solved the problem but with much more operating labor, more reagents and greater installation costs than the flotation step. About 100 to 150 gpm of fouled water is fed to two 66-in. Fagergren cells, in series. Reagents used at the beginning were Arquad 2HT75 and Arquad C50, at the rate of about 1% lb per 8-hr shift, or about 0.0053 lb each per ton of ore. This did not completely remove the solids but does an acceptable job. Approximately 75 pct of the slimes are a size that can be caught on a 41-Whatman Paper are removed. Removal of these slimes also allows much better settling of the coarse nonfloatable material. Advantage is also taken of this fact in a small settling tank ahead of precipitation. Removal of this amount of the slimes makes the ion t:xchange feasible. PREGNANT SOLUTION CIRCUIT The carbonate? leach-caustic precipitation method of uranium concertration does not provide for any process purification step ahead of precipitation. Therefore, any fine solids getting into the pregnant solution through the filter cloth show up in the final concentrate. This, of course, lowers the grade, and, at times, the slimy nature of these very fine solids rendered final filtration of the concentrate difficult if not impossible At Homestake-New Mexico Partners a 75-ft thickener was available for gravity clarification of 100 to 120 gpm of this pregnant solution. However this did not sufficiently remove the slimes. Laboratory investigation of the whole range of flocculants that were suggested by literature, salesmen, and friends failed to turn up anything of consequence. A continuous vacuum pre-coat filter would do the job and was investigated. The capital cost and the operating labor and materials made this a last chance choice. Following work done in the metallurgical laboratory on the tailings return water, it was found that some changes in the reagent strengths and combinations made a very definite decrease in the solids in the pregnant solution. Concentrate grade improved about 5 pct anti the final product after drying had an appreciably greater bulk density. Compared to a cost of about 2.2e per ton for pre-coat filter opelation for cleaning just one circuit, flotation costs less than 1.0 per ton of ore for cleaning two circuits. While a pre-coat filter would do a more thorough job, the flotation does all that is required for either circuit. Gravity causes the froth produced to run back into the leach circuit. This does not appear to result in a build-up of objectionable slime. No extra manpower is required; the operators in the separate areas can observe the operation of the cells and mix the small quantities of reagents as needed. Normally the 66-in. Fagergren cell requires 15 hp per cell, but this very dilute slurry needs only 10 hp for both cells. Originally, a combination of the two Arquads mentioned previously served as frothers and promoters. As further testing

Jan 1, 1962

By John T. Galey

The outstanding developments of the year in southwestern Pennsylvania were the establishment of the Summit Fayette County gas pool and the gas pool in Nicholson township, Fayette County, and Monongahela township, Greene County, as major producing areas, and the indication of four new shallow gas pools. Curtailment of drilling for shallow gas is expected to follow order M68 of the Office of Production Management. Gas completions were approximately 70 per cent higher, oil completions nearly 25 per cent lower, dry holes were unchanged and drilling wells as of Dec. 31, 1941, nearly loo per cent higher than last year. Shallow Development Oil.—Outside Butler County, only 11 producers were drilled, with a total initial of 221 bbl. The best of these was in a portion of Gilmore township, Greene County, which ordinarily produces gas. This well flowed 77 bbl. in 11 hr., along with about one million cubic feet of gas from the Fourth (U.Dev.) sand. Washington County had a 10.20 and a 25-bbl. well in Morris township and a 20-bbl. well in South Franklin township. These were all in the Fifth Sand. The price of oil to Jan. 27 was $1.80 per barrel, when a 15¢ increase was made. This was followed by a raise of 20¢ on Apr. 23, 15¢ on May 21, 20¢ on June 18 and 25¢ on Aug. 14. The last increase was canceled on Aug. 23 by the Office of Price Administration, which pegged southwestern Pennsylvania crude at $2.40 per barrel. Gas.—An almost doubled initial production of natural gas is the result of the large increase in number of wells drilled. The outstanding discovery of the year was in the vicinity of Armbrust, Hempfield township, Westmoreland County, where a well drilled to what at first was considered the Bayard sand, but what is now known to be the Fifth (U.Dev.) sand, at 2100 ft. found nearly 5 million cu. ft. of gas. Since this completion 14 wells have been finished, only one of which was dry, giving a combined total open flow of approximately 15 million cu. ft. The sand is 35 to 40 ft. thick and the saturation extends through most of that thickness. Rock pressure, which is 1040 lb. per sq. in., is abnormally high. An area of only about one square mile has been proven but some of the 24 new wells drilling as of Dec. 31 will no doubt extend it considerably. This development has taken place in an area heretofore considered to have had little prospect. There were three good wells in other parts of Westmoreland County. One well in Franklin township, which had 12 million cu. ft, of gas in the Fifth sand, was entirely surrounded by dry holes but is still pro- . ducing at a high rate. In Bell township a 1.6 million cu. ft. well was found in the Speechley (U.Dev.) sand and in Washington township the same sand produced 2.7 million cu. ft. with shut-in pressure of 970 Ib. at 2820 ft. This well is offset by two dry holes and one well with a capacity of only 10 M cubic feet.

Jan 1, 1942

By John T. Galey

The outstanding developments of the year in southwestern Pennsylvania were the establishment of the Summit Fayette County gas pool and the gas pool in Nicholson township, Fayette County, and Monongahela township, Greene County, as major producing areas, and the indication of four new shallow gas pools. Curtailment of drilling for shallow gas is expected to follow order M68 of the Office of Production Management. Gas completions were approximately 70 per cent higher, oil completions nearly 25 per cent lower, dry holes were unchanged and drilling wells as of Dec. 31, 1941, nearly loo per cent higher than last year. Shallow Development Oil.—Outside Butler County, only 11 producers were drilled, with a total initial of 221 bbl. The best of these was in a portion of Gilmore township, Greene County, which ordinarily produces gas. This well flowed 77 bbl. in 11 hr., along with about one million cubic feet of gas from the Fourth (U.Dev.) sand. Washington County had a 10.20 and a 25-bbl. well in Morris township and a 20-bbl. well in South Franklin township. These were all in the Fifth Sand. The price of oil to Jan. 27 was $1.80 per barrel, when a 15¢ increase was made. This was followed by a raise of 20¢ on Apr. 23, 15¢ on May 21, 20¢ on June 18 and 25¢ on Aug. 14. The last increase was canceled on Aug. 23 by the Office of Price Administration, which pegged southwestern Pennsylvania crude at $2.40 per barrel. Gas.—An almost doubled initial production of natural gas is the result of the large increase in number of wells drilled. The outstanding discovery of the year was in the vicinity of Armbrust, Hempfield township, Westmoreland County, where a well drilled to what at first was considered the Bayard sand, but what is now known to be the Fifth (U.Dev.) sand, at 2100 ft. found nearly 5 million cu. ft. of gas. Since this completion 14 wells have been finished, only one of which was dry, giving a combined total open flow of approximately 15 million cu. ft. The sand is 35 to 40 ft. thick and the saturation extends through most of that thickness. Rock pressure, which is 1040 lb. per sq. in., is abnormally high. An area of only about one square mile has been proven but some of the 24 new wells drilling as of Dec. 31 will no doubt extend it considerably. This development has taken place in an area heretofore considered to have had little prospect. There were three good wells in other parts of Westmoreland County. One well in Franklin township, which had 12 million cu. ft, of gas in the Fifth sand, was entirely surrounded by dry holes but is still pro- . ducing at a high rate. In Bell township a 1.6 million cu. ft. well was found in the Speechley (U.Dev.) sand and in Washington township the same sand produced 2.7 million cu. ft. with shut-in pressure of 970 Ib. at 2820 ft. This well is offset by two dry holes and one well with a capacity of only 10 M cubic feet.

Jan 1, 1942

By T. L. Joseph

THE committee appointed to investigate the application of oxygenated air to the blast' furnace believes, after a careful study of the problem, that this enriched air will increase hearth temperature, tonnage, flexibility of operation, and quality of pig iron made, and that fuel consumption will be decreased. These improvements are supported by theoretical evidence; but a practical trial of the process is necessary to establish more definitely the magnitude of benefits realized. The commercial application, however, may profitably be preceded by a test on a smaller scale. A small furnace will, in general, respond to the enriched air in the same way as a commercial furnace and the magnitude of the benefits to be gained from varying additions of oxygen can be fairly well established at relatively little expense. A new experimental furnace, being built jointly by the Bureau of Mines and the University of Minnesota, at Minneapolis, will have a capacity of about 6 tons and will riot require more than 700 cu. ft. of natural air per minute. Its hearth is 36 in. in diameter and its height about 32 ft. Enough oxygen to enrich the blast to the extent recommended by the committee can be obtained from a small oxygen unit. It might even be cheaper to perform preliminary experiments with tanks of oxygen obtained from regular, dealers. A procedure in making the test that suggests itself is to start with operation on normal air; then to use blast, enriched in several steps. Systematic temperature measurements of the tuyeres, slag, and metal would reveal any changes in hearth temperature. When these changes become large enough, the burden may be gradually increased to just within the breaking point and the furnace brought back to normal, if possible, by the addition of oxygen. Such a test would show what might be expected in the way of a decrease in fuel consumption and the time taken to "straighten up" the furnace by means of oxygen. The new furnace at Minneapolis is so equipped that the furnace process can be observed from the stock line to the iron notch. We have been taking gas samples at various elevations in the furnace to study combustibility of the fuel and the reducing power of the gas. If either of these is affected by removing inert nitrogen, the change can easily be measured.

Jan 11, 1924

By O. B. Hopkins

There was no noteworthy development in the oil industry in Peru during 1933 and all activities were restricted to the producing fields. The output of the country increased above that of previous years but there still remained a substantial shut-in production at the close of the year. The total production during 1933 is estimated at 13,259,891 bbl., of which the International Petroleum Co., Ltd. contributed 11,205,-362 bbl. A relatively small amount of new drilling was undertaken during the year. The International completed only one new well although a number of the old producers were reworked and deepened. Comments on Tables There are four oil districts in Peru, as shown in Table 1, although only three of these are now being operated. The exhausted Pirin field was abandoned eight years ago. La Brea-Parinus.—The La Brett-Parinas fields are on the property of the International Petruleum Co., Ltd. in the westernmost part of Peru. These fields include a number of producing districts that are defined by complex fault blocks associated with anticlinal folds. Data covering all the items listed in the table are not available on these fields but can perhaps be supplied in part in the future. Lobitos and Restin.—These two fields belong to the Lobitos Oilfields Limited and are near the coast, 10 to 20 miles north of the La Brea-Parinas fields. According to the Department of Mines and Petroleum of Peru, 311 wells at Lobitos and 197 at Restin had been drilled to the end of 1927. Since that date there has been enough drilling to increase moderately these figures. The depth of wells is not available but it is believed that their average depth is slightly greater than in the La Brea-Parinas area. The productive horizons are of Eocene age. zorritos.—The Zorritos field is the northernmost in Peru and is operated by the Establecimiento Industrial de Petroleo de Zorritos. The field is on the coast about 70 miles north of Lobitos. The number of wells drilled in this field to the end of 1927 was 343, according to the Department of Mines and Petroleum of Peru. The depths of these wells are reported to range from 300 to 700 ft. The largest wells do not produce

Jan 1, 1934

Discussion of the paper of PHILIP W. HENRY, presented at the New York meeting, February, 1915, and printed in Bulletin No. 97, January, 1915, pp. 23 to 30. C. ,E. GRUNSKY, JR., San Francisco, Cal. (communication to the Secret ary*).-The difference of opinion of engineers on the subject of depreciation is justified, to some, extent, by the many viewpoints from which such a subject can be considered when applied to properties of widely differing physical characteristics. Mr. Henry takes up the subject of depreciation as applied alone to oil properties, and in doing so makes a clear distinction between amortization and the repair or renewal requirement. After carefully reading the paper the purpose of its author in suggesting a "depreciation" reserve or fund to keep the property at a constant value does not seem clear. As shown by Mr. Henry, the depreciation element as compared with the operating expense per gallon of oil is very large because of the comparatively short life of the oil properties, and it is also evident that such a "depreciation" fund would in a short time contain a very large amount of money. It seems desirable and permissible in income-tax matters to take into account the depreciation of property and to separate from the income such money as is necessary to amortize the invested capital to an extent warranted by the depreciation. However, it does not seem either necessary or desirable to create a large fund which will in time approximate the entire invested capital and which may he invested by the directors, as Mr. Henry suggests, "in the property itself or in outside securities." This method seems cumberome and liable to offer in the reinvestment of such a fund temptations to a directorate that might show more devotion to its own interests than that of the stockholders. A reserve fund is very frequently desirable in mining and oil operations, but to keep up a fund of this magnitude or to reinvest it in outside securities does not seem desirable from a stockholders' standpoint. The. money withdrawn from the receipts to be placed in the depreciation fund (not including replacements and the drilling of new wells necessary to keep up the productiveness) should he returned to the stockholders of the company, not as dividends, but as an amortization of the invested capital.

Jan 5, 1915

By Arthur Dwight

WE NOT have to go so very far back, when measured in actual years, to what may be considered the beginning of the industrial era of the great West, the discovery of gold in California in 1848, just 74 years ago. By a strange coincidence, this event occurred within a few days of the signing of the treaty with Mexico which ceded California to the United States. Needless to describe the mighty wave of humanity that hurled itself toward the setting sun in response to that call. The single thought in every one's mind was gold. The gold as they found it in placers or ledges could be so easily worked, and the product was so readily transportable, and available immediately as money, that practically no attention was paid to deposits of the base metals, in the treatment of which cheap transportation was a paramount con-sideration; consequently little progress was made in anything but gold mining until after the Civil War. The next great step was accomplished when East and West were united by the successful construction of the Union Pacific Railroad from Omaha across the great plains and through the Rockies to meet the rails of the Central Pacific coming eastward across the Sierras. The industrial history of our great West really dates from the day when those two hands of steel were joined, on the shores of the Great Salt Lake at Prom-ontory Point,. May 10, 1869. That seems a long time ago when we think of the enormous changes that have been wrought since that day, and when we regard the rich empire that has sprung up in that western land. Into the new empire thus made accessible, by this first thread of steam transportation, flocked a new brood of adventurous spirits from the older communities of the East. This way walked Fate; and as she, went, flung far the line of destiny, That bound an untracked continent to brotherhood from sea to sea; That long gray trail of dream and hope, marked mile by mile with graves that keep On every barren hill and slope some stout heart lost in dreamless sleep. Patience and faith and fortitude were willed to it and justified; Stern, homely virtues, plain and rude, eternal as the sky and wide. Nor ever sea-king dared the sea in sterner mood than these who went Strong armed to wrest from Mystery their birthright, half a continent.

Jan 4, 1922

By R. C. Patterson

In view of the circumstance that very few important changes have been made within the last 15 or 20 years in the equipment of rod and wire mills, the description of a new process introduced by Grenville Mellen, of LleweIIyn Park, N. J., to take the place of the present laborious system of producing rods of lead, zinc, brass, copper, aluminum, etc., may be interesting to members of the Institute. This new process consists in the production of cast rods at one operation in a small continuous casting machine. The hot liquid metal is transferred from the melting crucibles directly into an endless chain of mold blocks in the machine, where solidification takes place, and the rod comes out continuously in a solid form at one end as long as the molten metal is supplied. The operation of these mold blocks so as to produce a solid rod of uniform structure constitutes an important part of Mr. Mellen's invention. The machine (Figs. 1 and 2), 12 ft. in height over all, 2 by 3 ft. in horizontal cross-sectional area, and 6,000 Ib. in weight, has a framework of cast iron, holding in position two endless chains of mold blocks, which are made in sections and join in center alignment. The mold orifice is made up of these mold sections, into which the liquid metal flows. The molding chains are composed of steel blocks, grooved on one face to form the molding cavity, and linked together with flexible joints. Each block is carried on four rollers which guide the chain around the end sprockets and carry it in its course through the machine. The accuracy of alignment requisite to the production of a perfect rod in the mold groove formed by these sections is secured by careful machine work, and by building the four ways, down which the alignment takes place, so that two of the sides are fixed permanently, whiIe the opposite sides are held to their position by spring pressure. The guides carrying the molds, while in casting position, are water-cooled square tubes. The length of this machine is somewhat indeterminate. A certain amount of both time and cooling surface is required to solidify the metal jn the mold; and one may either use a long molding chain and run it fast, or a shorter chain and run it correspondingly slower. We have found,

Jan 1, 1916

T. A. Rickard, Denver, Colorado: The observations made by the author concerning the treatment of gold-bearing ores, deal with the subject only briefly and in a general way; but, coming from an authority, they invite comment. In stating the fact that a " finely-divided condition " is a necessary characteristic of ores containing free gold, the author must be refer ring to those mining districts only with which he himself is ac quainted. The statement would not be true of certain gold-mining regions in America and Australia. The ores of some Californian mines and the mill-stuff treated at certain of the mills of Clunes and Ballarat in Australia, and of Otago in New Zealand, contain the gold in a free but in a coarse state. Moreover, "reduction to fine sand and flour" is not required by certain ores, even though the gold be in a finely-divided condition. In such cases the gold becomes de tached from the quartz before the gangue has been pulverized into particles as small as those in which the gold occurs. The dry-crushing of free-milling gold-ores is onknown in the new mining regions of the world. It is not clear whether the author has in mind any European district in which such a process is in actual use. If he has, a description of the method and the results obtained would be very valuable. Dry-crushing is, other things being equal, twice as slow and twice as expensive as wet-crushing. In the case of free-milling gold-quartz it serves no purpose, since such ore does not carry sulphides which contain any large percentage of value, and which, by being slimed, may carry away part of that value. The dry-crushing of a free-milling gold-quartz would be considered an absurdity by an American metallurgist. If the ore contain "free gold only," why submit it to a further treatment, such as concentration, after its passage over the amalga mating-plate ? What does the author propose to concentrate ? Again, why anticipate the treatment of tailings by the McArthur Forrest, or some other process ? The satisfaction felt by a mill-man in saving gold by a subsequent treatment of the tailings from his mill appears to me to be like that of the man who shoots at a rabbit,

Jan 1, 1894

By F. V. Lenel, M. V. Rose, A. B. Backensto

WHEN aluminum-flake powders are compacted and hot pressed and the resulting compacts are extruded or hot forged, a group of materials with unique properties is obtained. Not only do they exhibit high room-temperature strength of the order of some of the aluminum alloys, but they maintain this strength even after prolonged heat treatment at temperatures up to 900°F. Moreover, their strength decreases much less with increasing temperature than that of aluminum alloys of comparable room-temperature properties. Irmann,'" who discovered and first described this group of materials, which was called SAP, showed that the room-temperature mechanical properties of the extrusions are a function of the oxide content of the powders and therefore the oxide content of the extrusions. The higher the oxide content, the higher are their tensile strength, yield strength, and hardness, and the lower their ductility. Lyle" investigated the relationship between mechanical properties at elevated temperature and oxide content in the course of the development work of the Aluminum Co. of America on materials, called APMP, similar to those developed in Switzerland. He found that at 600 °F, just as at room temperatures, tensile strength and yield strength increase and elongation decreases with oxide content. A careful study of his data (Fig. 3, loc. cit.) shows, however, that the scatter is more pronounced than at room temperature. Gregory and Grant's data on the creep5 and stress-ruptureb roperties of the one commercial grade of the Swiss SAP and the various grades of APMP indicate that creep strength and stress to rupture also generally increase with increasing oxide .content. Ever since this new group of materials was discovered, attempts have been made to explain the mechanism by which they obtain their high room-temperature and particularly their elevated-temperature strength. In most of the attempts the new material was considered as a dispersion of aluminum oxide particles in a matrix of aluminum. Ir-mann, Von Zeerleder, and Rohner' applied a theory on dispersion strengthening developed by Rohners to the flake-powder extrusions. According to this theory the elastic limit S, of a dispersion would depend upon the average distance between the dispersed particles L according to the equation: 2 E ¦ a where E is the modulus of elasticity and a the distance between nearest neighbors in the lattice of the matrix material. Irmann and co-workers assumed

Jan 1, 1958

By C. L. Berrien

Many fires have occurred in the mines of Butte in recent years, and while all have been of a serious nature, simply because they were mine fires, six of them have been especially dangerous in respect to loss of life and property, and the expense of extinguishing or controlling them. It is not my intention to discuss the relative merits of methods used in fighting these different fires because the conditions under which they occurred varied in each case, and it was not always advisable to expend the large sum of money necessary to actually extinguish them if they could be bulk-headed off from the rest of the mine. It is needless to say that everything possible has been done to check all fires at the beginning, but without success in some cases; and it has then become necessary to bulkhead all connections to them, in which state several now exist. The mine fires of Butte, or fires in any mine, may be divided into two classes, namely: Those occurring in accessible workings, and those occurring in inaccessible workings; because these two conditions govern to the greatest extent the methods of fighting fires. Accessibility and inaccessibility in the case of mine fires concern not only new open workings and old closed workings, respectively, but also the condition of the ventilation in and about those places. When a fire is accessible at the start it should not be difficult to confine it to a small area and extinguish it in a relatively short time, but when it is impossible to actually reach a fire in old filled, abandoned workings, or there is no opening by which the gases may be conducted away from the fire zone, then the time consumed in changing those conditions permits the fire to increase to such an extent that it is a long, hard fight to overcome it. These different conditions have been met in Butte, and of the six fires of serious proportions the Steward mine fire and the High Ore-Modoc mine fire were in new accessible workings and were extinguished in a month or so. The Anaconda mine fire, the Leonard-Minnie Healy mine fire, the West Colusa mine fire, and the Mountain View mine fire, were all inaccessible. The Anaconda mine fie started about 25 years ago and though safely bulkheaded is still active. The Leonard-Minnie Healy

Jan 1, 1916

By John F. Knudsen

Following the flowsheet from the primary crushing plant of Ray mines division through the final products sample mill, there are eight exhaust systems ranging in size from 12,000 to 30,000 cfm. Where possible, hood face velocities are kept around 500 ft per min, permitting branch velocities of 2500 ft per min. Tight-fitting enclosures are provided over all ore drops, crushing operations, and vibrating screens. All enclosures are exhausted either primarily or secondarily, except those around conveyor head-pulleys where the ejector effect of the falling ore creates sufficient indraft to abate dust dissemination. IN 1947 an Industrial Hygiene Department was organized to represent and assist the four western mining divisions in industrial hygiene problems. Department headquarters are located at the Utah Copper Division, Magna Plant, Magna, Utah, with a branch office at the Chino Mines Division, Hurley, N. M. The headquarters staff includes a director, a department secretary, an industrial hygienist, a supervising ventilation engineer, and two ventilation designers. To be in closer association with work at the Southwest properties, a field engineer at the branch office conducts field studies which include ventilation problems at the New Mexico and Arizona properties;i.e., the Chino and Ray mines divisions. Functions of the department are to discover and evaluate existing hazards and to develop protective measures, either by personal protective devices or by proper ventilation, depending on the nature of the contaminant. Other than dust counting, all air samples collected at the four properties are processed at the home office. If through plant surveys or by suggestion of management some type of ventilation or air conditioning is required, the problem is usually handled by the ventilation section of the headquarters department, where general arrangement or line drawings are prepared, showing hoods, ducting, and equipment. Some hood and special parts detailing is done at headquarters; otherwise, required detailing is done by the respective plant engineering departments. Prior to the design of industrial ventilation, either new projects or the revamping of old ones, a thorough survey is made of existing conditions. In so far as possible weighted average exposures are determined and adequate ventilation provided on the basis of maximum allowable concentrations of the contaminant in question, as well as medical case histories, if these are available.

Jan 1, 1954

By R. M. Bird

Few persons outside of the foundry trade have any conception of the great variety of sands now regularly specified and furnished, nor of the differences in foundry practice frequently resulting from apparently minor changes in sands. Conditions in each locality where the sands are mined and prepared necessitate special equipment designed to perform the work efficiently. The description that follows of the foundry-sand producing operations is typical of the areas in New York and New Jersey, and particularly refers to the operations of the George F. Pettinos Co. A few years ago the so-called Albany sands were dug by simple methods and hauled by horsecart to railroad. Depletion of sand near railroad sidings and extended use of automotive power have appreciably extended the area from which sand is now being dug. It is not unusual to haul 5 miles to the railroad. As stripping is quite shallow, 6 to 18 in., and the banks of usable sand generally run from 12 in. to 4 ft., it is economical to work the bank by benches so narrow that the overburden can be thrown by hand shovel to the exposed bottoms. In effect the top soil goes back to where it was, but on a lower level. Consequently the general surface appearance of a mined acreage is the same as before. This condition is in fact cutomarily required when a farm owner sells his sand in the ground. After such replacement, in the course of 3 to 5 years the soil is no less fertile than it was before mining. The sand itself varies as to grain and bond vertically and also along the breast. No mechanical equipment has been developed to compete with hand shovels and no machine has as yet been devised that grades the sand as required. Uniformity of sand, as shipped, depends first, last and all the time on the man on the job. Mixing equipment can change the appearance of the sand and mask its lack of uniformity, but it will never correct wrongly graded sand, dug from the bank. Modern methods of testing are helpful in setting up standards against which the man in the bank can compare his sands, but a good bank foreman is the only assurance that the sand, as dug, matches the required sample.

Jan 1, 1926

By R. S. Shoemaker, R. M. Darrah

Expanded markets for copper in the past few years and a consequent search for new ore bodies have revitalized the widely known but seldom applied method of producing copper called heap leaching. Heap leaching is defined here as the process applied to oxide ores which have been mined solely for the purpose of leaching. In this case, all costs of mining the ore become a part (and a substantial one, as will be shown) of the cost of the copper produced, whereas in dump leaching the mining cost has already been accounted for as a stripping cost for the sulfide ore. Of course, with newly opened ore bodies, stripping costs may be divided through accounting procedures, between the copper produced by the mill and that obtained by leaching, but in general this type of operation must be economic on the basis of the sulfide ore alone. Heap Leaching Requires Low Capitalization Heap leaching, as a beneficiation method, is unique in that it is the only process used for the recovery of a metal in which the time involved from mining the ore to metal production is measured in months instead of hours or at the most, days. Then too, after the ore body has been depleted and mining has ceased, metal production will continue for some substantial period of time. Heap leaching is also unique because unlike any other method of beneficiation, metal recovery cannot be accurately forecast ahead of time and recovery will never approach that of a conventionally milled sulfide ore or even that of a vat leached oxide ore. Counter-balancing this drawback, however, is the relatively low capital expenditure necessary to put a heap leaching operation into production and the consequence that smaller ore bodies which would not support the higher capital cost involved in a vat leaching plant can be made into producers. Stated more simply, in heap leaching the operator accepts low recovery in exchange for low capital costs and low break even point. Whether the operator chooses vat leaching with its higher recovery and higher capital costs, is a mater of economics which depends in part on the nature of the ore to decide. For instance, an ore that will vat leach in 7 to 10 days using 7 pounds of sulfuric acid per pound of copper produced might use double or triple that amount of acid during the months that are required for heap leaching.

Jan 12, 1968

By ANDREW CARNEGIE

Although the noble building provided in New York City by Mr. Carnegie for the United Engineering Society has been pushed to about half-completion, the ceremony of laying its corner-stone was not performed until Tuesday afternoon, May 8, 1906. The stone lies just back of the southeast corner of the building, on the north side-of West 39th Street. Among those present were Mr. and Mrs. Carnegie, Miss Whitfield, the sister of Mrs. Carnegie, Ralph W. Pope, Secretary of the Institute of Electrical Engineers, Frederick R. Hutton, Secretary of the. Society of Mechanical Engineers, Rossiter W. Raymond, Secretary of the Institute of Mining Engineers, Charles H. Haswell, the first Chief Engineer of the United States Navy (1836-1851), now in his ninety-seventh year, John Fritz, of the Bethlehem Steel Company, William H. Fletcher, President of the Engineers' Club, E. E. Olcott, President of United Engineering Society, and other interested friends. After an inspection of the interior of the building, the group formed about the corner-stone, which had been draped with the American flag. The exercises were opened by Mr. Olcott, who appropriately welcomed Mr. Carnegie, and briefly expressed the essential value of the building, saying, in part " The societies to be housed underneath this roof have as their aim the pre¬serving and putting in tangible form of the records of scientific accomplishments so as to avoid the repetition of mistakes. The possibility of finding the records of these results all at one center, so near the great Public Library of our city, will be an inestimable advantage to all professions. It is an occasion of no ordinary moment, therefore, when we can welcome Mr. Carnegie and have him lay for us the corner-stone of this great building which his liberality has provided." Mr. Carnegie responded in happy vein, thanking the committee for their greeting, and expressing his pleasure. in being able to do what he had done to further so worthy a cause. Among other things, he said

May 1, 1906

By N. A. Gjostein

The self-diffusion coefficient D, for a surface near the (100) plane in copper was determined by means of the Mullins theory of thermal grooving, and was found to obey the Arrhenius relationship, and Do = 6.5 x 10' sq cm per sec. Suppression of surface diffusion by chemisorbed impurities encounters difliculties as a satisfactory explanation for the large Q, and Do. Instead, a model is presented which indicates that Q,, as determined by a mass-transport technique, may involve both the energy needed to form an adsorbed atom from a ledge in the surface as well as that for the movement of the adsorbed atom.; LITERATURE reviews1-3 indicate that the mechanism of self-diffusion on metal surfaces is not clearly understood. The lack of experimental data on the temperature variation of the surface self-diffusion coefficient DJ has contributed greatly to this situation. Radioactive tracer techniques4-rn have been used to measure Ds, but for many years only Nicker-son and Parker8 had determined (for polycrystalline silver) an activation energy B, and a frequency factor Do for the surface self-diffusion process. Even in this case, a mechanism could not be clearly inferred because it was suspeted7 that a contribution from volume diffusion was not taken into account by the investigators. Some later work by Li and parkere on polycrystalline gold, in which they obtained essentially the same results as for silver and in which volume diffusion could be accounted for, seems to invalidate this criticism. In 1957, Mullins10'11 developed the theory for the thermal grooving process. This advance has opened a new and promising technique for measuring the surface self-diffusion coefficient Ds. Recognizing that a thermal groove may form by several different mass transport processes, Mullins first consideredlo the cases where a) the groove forms by evaporation and condensation or b) by diffusion along the groove surface, in either case, in a system where a metal surface is in contact with only its dilute vapor phase. In a later paper," he extended the treatment to cases where the groove forms by volume diffusion into c) the solid phase or d) by mass transport through a passive gaseous phase at 1 atm pressure. The time dependence of the groove dimensions and the shape of the groove profiles predicted by Mullins' treat-

Jan 1, 1962

May 219t, 1872. THE Institute assembled in the rooms of the Geographical Society at the Cooper Union, Tuesday evening at 8 P.M. President Raymond called the meeting to order, and introduced Mr. Abram S. Hewitt, who welcomed the Institute to New York. President Raymond, in behalf of the Institute, replied. The President then read the following report of the Council for the past year. The Council respectfully report that the American Institute of Mining Engineers has held four meetings-at Wilkes-Barre, Bethlehem, Troy, and Philadelphia, respectively-all of which have been well attended, and socially and professionally most successful. The proceedings of these meetings having been published in the Engineering and Mining Journal, and sent to all members and associates, are sufficiently well known. Forty-four papers, by twenty-six authors, have been read. These papers embrace s wide range of subjects, and prove the practical character of the proceedings of the Institute. The finances are in a satisfactory condition. By the report of the Treasurer it appears that $1290.10 have been received, $519.90 expended, and that $770.20 now remains in the treasury exclusive of fees for 1872. This fund, it is hoped, will be so increased by voluntary subscriptions as to enable us before long to issue s volume of our most important transactions in a permanent form. The Council has made a favorable arrangement with the Scientific Publishing Company, publishing the Engineering and Mining Journal, by which that journal became the organ of the Institute for the first publication of the proceedings, papers, and notices to members. This arrangement it is proposed to continue through the present year unless the Institute shall otherwise direct. It is not intended to supersede the publication of an annual or occasional volume, but to maintain an interest in the Institute, and to serve the convenience of members while our funds do not permit s more ambitious publication.

Jan 1, 1873

By W.G. Woolnough

There has been no noteworthy increase in production during 1935; but, on the other hand, there have been ample manifestations of a considerable increase in interest and activity in connection with petroleum prospecting. The Lakes Entrance field, in the State of Victoria, on the coast some 120 miles east of Melbourne, remains the only actual producer; and this production, consisting of lubricating stock devoid of light fractions, is very small in amount. Arrangements have been completed under which a series of "scout bores" for structure testing in the region of Lakes Entrance will be sunk by the Government of the State of Victoria, assisted by a subsidy from the Federal Government. Prospecting In the State of New South Wales, brilliant geological research in very difficult country, carried out by geologists of Oil Search Ltd., has revealed several previously unsuspected domal structures in the Sydney-Newcastle coal basin. These have been mapped in detail, and a test well is being sunk at Kulnura, 10 miles west of Wyong and 40 miles north of Sydney. At the date of writing this well has reached a depth of 1250 ft., 10-in. casing having been set at 1248 feet. Superficial formations consist of the Hawkesbury sandstone and Narrabeen beds of the Hawkes-bury system (fresh-water Triassic). It is anticipated that the upper coal measures of the Kamilaroi (Permo-Carboniferous) will be entered almost immediately. The objectives of the drilling are the upper and lower marine beds of the Kamilaroi system, which are regarded as promising as potential source—and reservoir—beds for oil. At Mulgoa, 30 miles west of Sydney, a bore is being sunk by the same company, Oil Search Ltd., to test for natural gas on a well defined structure located by the company's geologists. Noteworthy flows of gas have been encountered, but nothing approaching a commercial supply has been struck. It is considered probable that the gas has been derived

Jan 1, 1936