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By D. A. Lyon

Discussion of the paper of DORSEY A. LYON and ROBERT M. KEENEY, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1707 to 1730. LAWRENCE ADDICKS, Douglas, Ariz.-I think papers of this character, while general in, nature, are of particular value and interest, because when we figure on competing with the East in electrometallurgical industries, on account of the cheap power on the Pacific Coast, we have to take two or three things into account. In the first place, power very rarely amounts to more than 20 per cent. of the total cost of an operation, even .though it be electrometallurgical, and I think it is the common opinion among those who are not familiar with those particular industries, that it amounts to more than 50 or 60 per cent. Take copper refining; we may say that it is 15 per cent. of the total cost. In the second place, around New York City, with 100 per cent. load factor and a reasonably large load, say 10,000 kw., we can generate from a certain class of coal 1 kw.-hr. for about 0.3c. I might say, however, that 0.3c. does not include overhead charges, interest on the investment, etc. The third factor we have to consider out here is that any product to be salable, must command a retail market. It would be useless to produce wire bars here on the Pacific Coast because there is no place to roll them. If we were going to establish a copper refinery, that part of its output which goes into wire bars would have to be taken care of by building a rolling mill alongside of it to turn it into wire and finally make a product that is salable. I do not think, however, that Mr. Lyon need have excluded copper refining from his industries. There are perhaps 50,000,000 lb. of copper a month refined in this country on a custom basis. I think the smelting companies would be very glad to build refineries here if conditions warranted it. The recent extensions of the Great Falls refinery and of the Tacoma refinery in the last few months give evidence of that.

Jan 12, 1915

By Lester A. Blackner

Discussion of the paper of LESTER A. BLACKNER, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 102, June, 1915, pp. 1249 to 1290. SIDNEY J. JENNINGS, New York, N. Y.-In the historical part of the development of the caving system discussed by Mr. Blackner, I notice the absence of one man's name, Charles Henroten. Mr. Henroten used the caving system in South Africa in the. Kimberly mines, and realized from his work there that ground would cave when properly prepared. I think it is due him that his name should be mentioned in connection with an exposition of this system in America.

Jan 12, 1915

By R. P. McLaughlin

Discussion of the paper of R. P. McLaughlin, presented at the San Francisco meeting, September, 1915, and printed in Bulletin 'No. 108, December, 1915, pp. 2313 to 2319. M. E. LOMBARDI, Berkeley, Cal.-Mr. Bell, I would ask you to state before the meeting what you said to me the other day, about the final recovery of oil from oil sands that have become inundated with water. A. F. L. BELL, San. Francisco, Cal: In stating my opinion, I give it with certain qualifications. In the Kern field, and possibly in some others, I think we will eventually get all the oil out, whether the water comes in or not, since it is peculiarly constructed, being in the form of a partial dome. In 1909, while I was field manager of the Associated Oil Co., I installed some large air compressors to handle the water. At that time the oil had migrated to the higher and more shallow portions of the field, because the water had inundated the deeper sections. The result was that the shallow districts within the center of the dome were in many, cases producing as much or more oil per well than the deeper wells. And in the inundated sections the water had slowly spread over large areas, so that nothing but water was pumped from them. Under these conditions, we decided to pump the wet. well with air, and installed four 2,000-cu. ft. compressors. The air was compressed and forced into the wet wells at, about 250 lb. pressure. Shortly the inundated district that had produced almost all water and only about 150 bbl. of oil a day increased its production to over 2,000 bbl. of oil per day. It was not-long before, we noticed that the production of the shallow territory was falling off to such an extent that in many cases the wells were abandoned; at the same time the area of the water-inundated district was greatly reduced, showing that when the water pressure was reduced the oil migrated back to the lower depth. The wells which at first had had the air jets put into them finally produced so much oil that we had to take the 'air jets out and return to the use of the beam pump, because it is not commercially feasible to pump, an oil of 14° gravity with air. To handle such oil profitably by air, it must carry with it 50 to 90 per cent. of water. The results have led me to believe that oil monoclines, where there is a gradual rise to a certain point, or in plunging anticlines, even though water gets into oil sands, eventually we get the larger percentage of the oil. However, the man with a small acreage in the deeper sections may find some morning that his oil has gone, another man in some higher portion of the district having gotten it.

Jan 12, 1915

By R. P. McLaughlin

IN most branches of the mining industry it is a well-recognized fact that care must be taken to protect the mineral deposit from undue physical injury. It is comparatively easy to grasp this idea when the mineral is a solid and the lives of workmen depend directly upon the care with which it is removed from its natural position, but when the product is a liquid. drawn up from pools several thousand feet beneath the surface of the ground through openings only a few inches in diameter, it requires some imagination to picture underground conditions and the changes which must often occur. The development of the petroleum deposits of California has been attended by numerous accidents, the results of which are readily noticed at the top of the wells and in the profit and loss accounts of the operators. Determination of the cause of these accidents has been the subject of considerable study, which naturally has fallen upon men familiar with technical methods. The greatest damage to the oil deposits of California has resulted from water finding its way into the oil-bearing sands, and it is the purpose of this paper to set forth briefly this phase of the oil industry. Much of the material here presented has previously appeared inn publications issued by the California State Mining Bureau, which, under the direction of State. Mineralogist Fletcher McN. Hamilton, has investigated the subject and taken steps toward improvement of conditions. The writer, having been in charge of this branch of the Bureau work, has gained considerable knowledge of existing conditions.

Jan 12, 1915

By Charles Jones

Discussion of the paper of CHARLES COLCOCK JONES, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1887 to 1898. D. A. LYON, Salt Lake City, Utah.-For some years I have been interested in the iron-ore deposits of the Pacific Coast, and I feel very much indebted to Mr. Jones for the information he has given us on this subject. I think that we are also very much indebted to him for having presented this paper, as he has given us reliable data in shape of facts and figures, which is just what we need in considering whether or not it would be commercially feasible to attempt to establish an iron and steel industry on the Pacific Coast. Personally, due to lack of market, I do not think it is a commercially feasible proposition at the present time. Mr. Jones states that pig iron can be produced on this coast as cheaply as it can be produced in Pittsburgh. Even. so, what can be done, with it after it is produced? To begin with, iron produced on the. Pacific Coast has to compete with iron produced in China. Last year I had occasion to investigate the subject of the market for iron and, steel on the Pacific slope, and found that it was possible for the producers of Chinese iron to sell it for much less than the price for which iron can be produced in the West, and also for less than eastern pig iron is now sold for, even when shipped through the Panama Canal. I was informed that the agents for Chinese iron had instructions to sell it for $1 or $2 less per ton than that asked for other irons on the market. Of course, I realize that the competition of Chinese iron may not be important, but even if it is not, and even though pig iron ,can be produced at the cost given by Mr. Jones in his paper, I do not see any immediate chance of its being so produced, due to lack of market. C. C. JONES, Los Angeles, Cal.-Mr. Lyon is right. It is a fact that Chinese pig is being sold in San Francisco on some large contracts at $18.50 a ton, while $19 is the usual price. We ought to produce iron. on this coast at $14. Personally I do not think Chinese iron is ever going to be an important factor. It is a bugbear out here now. You are not going to have much Chinese pig iron in .this country. Our little friend Japan is going to absorb everything it can. The price of Chinese pig iron at $18 is about as low as it will ever get. If we can show you that we can produce this iron here at the same price as at Pittsburgh, I. think you will have a good opportunity to compete with anything China or India can ever do. Costs there are very low now. They are going to come up by leaps and bounds in the next few years. The labor cost over there may be very low now, but I. have seen some men from there quite recently

Jan 12, 1915

By Walter McKee

WHEN mixed with common cast steel in quantities ranging from 11 to 13 ½ per cent. and properly treated, manganese increases the ductility of the metal and adds greatly to its toughness and resistance to abrasive action, which properties comprise the distinctive characteristics that make manganese steel so valuable for many purposes at the present time. Manganese steel has been manufactured for about 26 years. .It was first made in a small way in England and subsequently produced in the United States in 1892. At present the manganese-steel foundries of this country have an annual capacity of about 60,000 tons and most of the growth has occurred within the past 10 years. In the early days of the industry it was impracticable to make manganese castings weighing over a few thousand pounds, but at present crusher heads, rolling-mill pinions, and similar castings weighing up to 30,000 lb. each are produced, and it does not appear that the limit of weight has been reached by a considerable margin. Manganese steel is similar in analysis to ordinary first-class converter metal except that it is high in carbon and contains from 11 to 13 ½ per cent. of manganese. From one standpoint manganese steel is similar to malleable iron in that the casting as it comes out of the sand is hard and brittle and must be made ductile by a heat-treating process. The heat treatment is an essential part of the process of making manganese-steel castings and must be properly carried out to secure satisfactory results. The necessity for heat treatment limits the thickness of sections which may be made of manganese steel. Originally the annealing depth was comparatively small, but researches carried on during the past few years have resulted in an increase in the thickness of section up to 5 ½ in., which it is possible to treat successfully. Large castings are cored out to a minimum thickness of 5 ½ in., thus not only eliminating some of the internal stresses which are invariably set up in a very thick casting, but also reducing the weight and inertia of the piece, an

Jan 12, 1915

By E. B. Thornhill

Discussion of the paper of E. B. THORNHILL, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1653 to 1670. D. B. HUNTLEY, Oakland, Cal.-About 15 years ago it chanced to be my lot to cyanide some mill tailings, assaying about $5 per toll in gold and, a few cents in silver. It was in southern Idaho, a. desert region where costs are nearly as large as in central Nevada. We knew that we had a lot of tailings that had been amalgamated and contained about 1 lb. of quicksilver per ton. We knew that we would dissolve some of the quicksilver when we cyanided them with say 0.25 per cent. cyanide solution. We figured (optimistically) that the cyanide would dissolve all of the quicksilver, and we thought to capture all of that, 1 lb. per ton; and we figured out profits as partly gold, partly silver, and partly quicksilver from the recovery in working those tailings. Actually, however, we did this: We had a battery of three large, old-fashioned silver-mill retorts. We retorted our zinc-dust precipitate, recovering about ¼ lb. of quicksilver per ton treated. That was only a loss of 75 per cent. of what we originally had, but still it was profitable by virtue of the conditions. I mention it partly to call attention to the crude old way of doing it, and partly to call attention to how chemical methods for recovering quicksilver have developed in the last 15 years.

Jan 12, 1915

By Kenneth Seaver

Discussion of the paper of KENNETH SEAVER presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1913 .to 1927. J. W. RICHARDS, South Bethlehem, Pa.-This paper concerns a very large industry, and an important detail in that industry. Within sight of where I live in Bethlehem, Pa., are coke works in which $2,500,000 was lost by the use of improper bricks in the coke ovens. This was the fundamental reason of the failure of the plant. The old ovens have all been torn out and replaced by new ovens built of proper bricks. This may emphasize the commercial importance of this subject. When speaking about coke-oven brick, the first thing that comes to my mind is how important it would he if it were possible to. get a brick of better heat conductivity. The heat for coking coal has to go through the thickness of the brick. The silica brick used has low heat conductivity as compared with some other refractories; magnesite brick probably has four times its heat conductivity. The coke oven needs bricks of high heat conductivity. Any process which would increase the heat conductivity of silica brick would undoubtedly shorten the coking process.

Jan 12, 1915

By Henry Hibbard

THE process of making washed metal now followed is in principle that described by Holley before this Institute in 1879, as the Krupp washing process. Sir Lowthian Bell also experimented extensively in England during 1877 and 1878 on refining iron and joined his interest with Krupp, the process being often referred to as the Bell-Krupp process. The only plant in this country now operating this process is that of the Brier Hill Steel Co., Youngstown, Ohio. This process may be considered as the sole survivor of the numerous methods conceived for refining crude iron, when the removal of phosphorus from steel-making material was the great desideratum affecting large districts. The east coast of England and all northern Germany, the homes of Bell and Krupp, respectively, could at that time make steel only from imported ores. These processes were in use or in various stages of development 40 years ago and all except the Bell-Krupp received their quietus from the development of the basic steel processes, both pneumatic and open hearth. The aim of the early refining processes was, first, the removal of the silicon; which could be clone on a sand bottom, and later, the removal of the phosphorus, requiring a bottom which would give or permit a basic slag. The incidental advantages of increased yield and small fuel consumption were not generally recognized or considered; the aim of the later. operations was the saving of the difference in value between low and high phosphorus irons, as well as hastening the removal of the metalloids. The chemistry of the washing process follows in part that of the puddling process, and indeed washing might, be considered as the first half of puddling, since all the non-ferrous elements of the crude iron, except the carbon, are eliminated and the iron is maintained molten until cast. In puddling, the iron loses its carbon as well, and because of that, its fusion point rises above the hearth temperature; it freezes into a pasty malleable form, and is worked at once by squeezer, hammer, or rolls.

Jan 12, 1915

By Gerald Sherman

(San Francisco Meeting, September, 1915) THE ore deposits of the Warren district, in which the mines of the Copper Queen Consolidated Mining Co. are situated, have been described in a number of technical publications, and will not be-discussed here in detail. Certain of their characteristics, however, control -methods of underground transportation and hoisting of ore. In the Copper Queen mine, the majority of the ore has occurred in a zone encircling the west boundary of the porphyry intrusion of Sacramento Hill. It has a width varying from 800 to 1,200 ft., and a thickness of about 400 ft. It reaches the surface in the older part of the mine to the northwest, but dips to the southeast, where it is reached at 1,400 ft. below the Czar collar, in its farthest extension at present developed on Copper Queen ground. There is one major extension from the northwest end of the zone toward the west along the Czar fault, and others of minor importance. Individual orebodies are scattered through the zone in an eccentric manner, only matched by their own irregularities of form and size. Their most general characteristics are the softness of the ore and their great horizontal rather than vertical extent. It has been estimated that the average vertical thickness of ore in the Czar and Lowell divisions is between 30 and 35 ft. It is calculated by assuming it to be uniformly distributed over its horizontally projected area. In this zone, and for some distance above it, the ground has been .subjected to intense alteration and intense but irregular oxidation. It has resulted in an enormous quantity of earthy or clayey material, which may be either ore or waste, which when wet is both heavy and tenacious. Below alteration, the ground is fairly hard, and the limestones contain primary ores differing from those heretofore considered typical of the camp, and which have not yet been thoroughly exploited. The mine production has been drawn from many orebodies spread . over a great area. A diagram map (Fig. 1), of haulage drifts and loading stations, illustrates the situation in 1914.

Jan 9, 1915

By R. Dawson Hall

THE stresses in the e simplest structures are often those we find most difficult to analyze. The most complex condition in mine stresses is found in simple tunnels where the roof, the sides, and the floor are a monolith. The functions of the parts are like the parts themselves not distinct and specialized, and the problems to be solved are like those in a metal structure with riveted joints or a redundancy of bars. This difficulty explains perhaps why the condition has not been treated. But just because it cannot be discussed in its entirety is no reason why it should be treated as an action of parts with specialized functions as a roof 'beans with supports and a foundation. The problem cannot be ignored on the ground that it is not of sufficient importance to warrant careful consideration, because conditions of complete monolithism, of which the tunnel is the type, are found materially unchanged) in room-and-pillar and in longwall work. This unity between roof, sides, and floor, which to the coal miner is a difficult conception, really deserves a scientific appellation, and perhaps holoid (from holos, whole, and eidos, form) will serve the purpose as well as any other. In a simple tunnel the roof, the sides, and the floor form integral parts of one and the same structure; and the distortion of one cannot be conceived without a consequent strain in the others. Thus when the roof of the tunnel droops by reason of its weight, the upper parts of the sides are drawn in because they are integrally-connected with the roof and must approach each other whenever, by the sagging of the roof, the distance between any two points in it is diminished. (See Fig. 1.)

Jan 9, 1915

By Charles Jones

(San Francisco Meeting, September, 1915) IN any discussion of this very large subject we are confronted at the outset with so many obstacles that at best only a fragmentary and rather disconnected presentation can be made of it, and my hope is that building from the few facts I have to offer a more complete knowledge may be secured. In the whole intermountain and Pacific. Coast region, west of Pueblo, Col., and from Canada to Mexico, there is no production of pig iron, and steel production is confined to the manufacture of a small amount of open-hearth steel from scrap. When we consider the area, the resources, and the several centers of population, this condition seems anomalous, even in. the face of every counter argument as to cheap water transportation, or other means of transport from the Atlantic Seaboard or from the iron and steel centers of the Middle West. This comatose condition, if such a term may be applied, is certainly riot due to a lack of all the essential materials and factors for success in iron and steel smelting, but is rather, I think, due largely to the general fact that it is only within a comparatively few years that the centers of population on the Pacific Coast have attained a size that would entitle them to the position of distributing or freight centers, or that the "back country" has been enough built up to make it sufficiently interesting to the railroads to foster trade from the local centers to the interior points rather than seek to supply such local centers and the interior by a transcontinental haul.

Jan 9, 1915

By Charles Legrand

(San Francisco Meeting, September, 1915) THE problem of mine pumping is so much affected by local conditions, and those conditions are so liable to changes during the life of a mine, that the best system to use is difficult to determine. The experience of the;, writer has been that, in general, for copper mines, electric pumping is most satisfactory unless the quantity of water to be pumped is great or. the mine does not use electric power for any other purpose. As a rule, however, figuring on the cost of necessary power plant, the total cost of: installation is greater with electric pumps than steam- pumps. As the water is liable to be gritty, outside-packed plunger pumps are to be recommended, and if the water is not acid, or only slightly so, chilled cast-iron plungers pay for their extra cost very quickly in diminished cost of packing. With chilled plungers it is possible to use metallic, packing instead of soft packing, if the water, is not too gritty nor the lift too high. In vertical pumps this packing is satisfactory for lifts up to 400 ft., in the experience of the writer; and may be found satisfactory for higher lifts. For water slightly acid, cement-lined pump bodies have given good satisfaction. For acid. water, both plungers and pump bodies should be made of acid-resisting bronze. For high lifts, especially with gritty water, a satisfactory pump valve is difficult to find. To reduce the unbalanced pressure on the valve at time of opening it is advisable to have narrow seats; this, however, brings high pressure on the seats when the valve is closed. On large valves for lifts of 600 to 1,000 ft. we have used leather, hard rubber, vulcanized fiber, and soft brass; for clear water the latter has given best satisfaction. The difficulties due to grit make it advisable to have large sumps where water can settle, and if possible, to have two of them so that they can be cleaned alternately. At the mines of the Old. Dominion Copper Mining ,& Smelting Co.; Globe, it was found that a small air. ejector discharging into a mine car is a very convenient way to clean mud and sand from a sump. .

Jan 9, 1915

To the Members It has been, and is the endeavor of the A. I. M. E. to serve each and every member. One of the means of letting the membership know what is going on in the mining; metallurgical and chemical fields, and by far the most important, has been our monthly Bulletin. To publish this costs money, and to partly defray the costs, it was decided to accept such advertising as could be secured. The A. I. M. E. is the only one of the American National engineering societies whose dues are as low as $10 per year, and it actually spends more upon the Bulletin and Transactions than the sun total it receives for clues. Hence the need of advertising revenues. We are planning even greater improvements for your Bulletin-improvements that will help you in your work. It will mean a better publication, with more information than ever before. To successfully carry out our plans, we must have your co-operation. We are not asking you for financial, but for your moral support. With that we shall accomplish a great deal. What we ask of you, brother member, is to give evidence to those patronizing our advertising pages, that you not only read the editorial pages, but the advertising section as well, and that you have in mind the welfare of your Institute by consulting the advertising pages when in the market for equipment. Do you realize that if you mention your Bulletin when writing advertisers or purchasing supplies, that not only would your publication secure more advertising, but better satisfy present advertisers. We have reason to know that our advertisers secure business as a result of our publication, but they demand some evidence that you see their advertisement. Unfortunately, our members do not as a rule mention where they saw the advertisement, and as a consequence advertisers have no means of knowing whether their investment in the Bulletin is paying. The A. I. M. E. Bulletin can be made the best advertising medium in the mining, metallurgical and chemical fields, simply by each member doing his bit. It is very little to ask of you, and the returns to the mining industry will be enormous.

Jan 9, 1915

By L. G. Huntley

I. HISTORY OF OIL DEVELOPMENT IN MEXICO THE occurrence of oil or "tar" in Mexico was mentioned as early as the seventeenth century by Friar Sagahun, who gives the Indian name "chapopote," by which these asphalt seepages are still called. This asphalt was apparently used, as it has been used by primitive people in many parts of the world, in religious ceremonies and for medicinal purposes. Travellers also report that the ruins in Yucatan and the pyramids in southern Mexico show traces of the use of "chapopote" as a building cement.1 DeGolyer says that the first attempt to exploit oil or gas in Mexico in a commercial way is shown by the records of the Memoria de Fomento of 1865, when permission was granted to a Senor Ildefonso Lopez to exploit the deposits of petroliferous substances in the San Jose de Ias Rusias area in the State of Tamaulipas. Other concessions follow, and probably refer to surface seepages which occur in that district. This was several years after the discovery of oil in Pennsylvania. In 1868, a well 125 ft. deep was drilled by a company organized in Mexico City, in what is now known as the Furbero district, and a little oil was refined there. In 1873, residents of Tampico denounced seepages along the Tamesi River, and asphalt was mined near Tempoal in the Canton of Tantoyuca. No drilling was attempted. But between 1880 and 1883 several shallow wells were drilled for oil in Mexico, two of them being near the present Potrero de Llano field west of Tuxpam. The wells were drilled by a Boston company with Canadian rigs, and are said too have reached a depth of about 400 ft., while one is reported to have flowed. Several other abortive attempts were made to drill for oil between 1885 and the beginning of the present century, about which time the Mexican, Petroleum & Liquid Fuel Co., Ltd., in which Cecil Rhodes was interested drilled 24 wells unsuccessfully, several of them as deep as 1,500 ft., in the State -

Jan 9, 1915

By S. E. Bretherton

(San Francisco Meeting, September, 1915) DURING the year 1878-79, Anton Eilers, who was then interested in the lead smelting and refining business near Salt Lake City, Utah, made a somewhat radical departure from the regular practice at that time, which was to use but little lime in the slag, with a high percentage of iron. Lime was not only a cheaper flux than iron, but it enabled the metallurgist to make a more siliceous slag, an economical advantage in smelting where the smelting companies had to purchase either iron or lime to neutralize the excess silica, and penalize the ore shippers accordingly. The larger amount of both lime and silica in the slag also made it of lighter specific gravity, and a better separation of the metals and mattes was secured. This change in the formation of slags for lead smelting was brought about by Anton Eilers, prior to the Leadville mining excitement of 1879. We must also give Mr. Eilers credit for the general introduction of the hollow water-cooled cast-iron jacket for the blast furnace. Again referring to the use of more lime and less iron in the formation of slags,. there is no doubt but that it prevents the formation of a great many so-called "sows" in the lead crucible, such as were made in the early history of lead smelting in the Rocky Mountains; these sows consisted of lead, iron, arsenic, sulphur, copper, and other metals, including gold and silver, mixed with unconsumed fuel, and often, after vain attempts to cut them up or melt them to a suitable size for handling, were buried in the slag clumps to get them out of-sight. Another advantage derived from the adoption of high-lime slags. when smelting ore containing arsenic is the production of less speiss (a by-product heavier than matte, resulting from careless operation of the furnace, the lead being driven out of the crucible and sows built up). This speiss, while usually not as rich in precious metals as matte made at the same time, is too valuable to be thrown away; but it is difficult to treat, and it was thrown away or piled on the slag clumps in the pioneer clays of lead smelting in this country.

Jan 8, 1915

The Manufacturer's Viewpoint A prominent manufacturer of mining 'machinery not long ago expressed himself as being confident that he was securing the best kind of publicity for his product through the advertising pages of the monthly Bulletin of the American Institute of Mining Engineers. Such an expression coming from such a man is highly gratifying; yet it is justifiable when the high quality of reader and subscriber is taken into consideration. In fact, the majority of those using our advertising pages feel the same. It is to be regretted, of course, that others catering to our field do not realize the means at their disposal for presenting the points of interest of their product to the mining man. The question has been asked, " Do your members read their Bulletin?" They not only read the editorial pages, but they "admit being up-to-date enough to peruse the advertising section to "see what is new." The next question the prospective advertiser asks is, " Will the Bulletin bring inquiries?" The answer to this question holds good for any publication having as subscribers those who have purchasing or recommending power-yes, if the article advertised is not a stock one, that has been before the public for any length of time. To secure inquiries on, say, a standard centrifugal pump or any other standard product, the features of which are well known, is a most difficult proposition. Yet, of course, some inquiries are secured, but mostly from those having use for the catalogue or trade literature for reference purposes. It is safe to say that the traceable returns from advertising in trade publications hardly, if at all, pay for the advertising. The real returns are intangible, and result from the constant publicity, and keeping ?everlastingly at it." Who can say what subconscious effect is taking place when an advertisement is "glanced at," to say nothing of the effect produced when the copy is attractive and interests the reader. Time after time it has been proved that sales have been secured as a result of an advertisement, yet no inquiry had been made directly traceable to advertising.

Jan 8, 1915

By W. J. Sharwood

(San Francisco Meeting, September. 1915) THE assay or estimation of the total gold content of an ore presents little difficulty, when circumstances permit of securing a thoroughly representative sample. The general practice has been fairly standardized, and such errors as occur in the results obtained are for the most part attributable to the methods of sampling rather than to those of assaying, while duplicate assays made by skilled workers usually agree closely. When it is a question of estimating the "free" or amalgamable gold of an ore, as opposed to the total gold, there is but little uniformity in the methods employed by different workers, and often equally little in the results obtained when duplicate determinations are attempted, no satisfactory standard method having been generally adopted. The methods in use are of two general types-"panning" and "amalgamation."

Jan 8, 1915

By F. D. Weeks

THE Salida smelting plant, owned by the Ohio & Colorado Smelting & Refining Co., is situated at an altitude of 7,000 ft., about 2 miles west of Salida, Colo., and 215 miles southwest of Denver. Salida is a division point on the. Denver & Rio Grande R. R. where the narrow-gauge line serving the Sari Juan region joins the through standard gauge. This narrow-gauge road also serves the coal and coke companies at Crested Butte and the lime quarries and mines at Monarch and Garfield, which are only 20 miles distant. These facts, together with the possibility of an appropriate site, doubtless influenced the builders to locate at this point. The smelting plant and yard occupy 80 acres of land on the northeast side of the Arkansas River. The slope of the ground is such as to permit of the ore being delivered by cars at a point 25 ft. above the feed floor; and in front of the furnaces there is a fall of 50 ft. for the slag clump. A recent purchase of river bottom has provided slag room for 20 years. As originally constructed, the plant consisted of four blast furnaces, 40 by 144 in. at tuyeres, two copper-matting furnaces, dust chamber, stack, power plant, blowers, sampling works, and one railroad trestle about 16 ft. from bed floor to rails. Later 12 hand roasters of excellent design were added and the practice of smelting leady matte in-a copper-matting furnace was abandoned. Since the plant passed under the present management the equipment has been increased so that the following is a brief description of the same at this date: Two lead blast. furnaces, 48 by 180 in. at tuyeres, 17 ft. 6 in. tuyères to feed floor; four lead blast furnaces, 40 by 144 in. at tuyères, 17 ft. 6 in. tuyères to feed floor; two copper-matting furnaces, not used; blast-furnace flue, 900 ft.; area 245 sq. ft.; blast-furnace stack, 150 ft.; above furnace floor, 190 ft. When smelting a 500-ton charge per day, the gases approximate 63,700 cu. ft. per minute and travel at a speed of 260 ft. per minute.

Jan 8, 1915

By Allan Clark

(San Francisco Meeting, September, 1915) IT is nearly three years since the metallurgy of the Homestake ore was discussed with considerable thoroughness, in a paper' read before the Institution of Mining and Metallurgy. Certain changes have been made in this period which are perhaps of sufficient interest to justify a brief description, and it is chiefly with such details and miscellanies that this paper will deal. In the circumstances, a certain amount of repetition is inevitable, but matter treated of in the former paper will be referred to here only when it is necessary for the sake of coherency. For full descriptions of equipment and technique, the former paper should be consulted. The mineralized slates and schists which constitute the ore vary considerably in composition, but the unoxidized ore, perhaps constituting the major part of the reserves, contains either chlorite or hornblende (cummingtonite), with quartz, carbonates of lime, magnesia and iron, and arsenopyrite, pyrite, and pyrrhotite. Ferrous minerals predominate, and this fact has been an important factor in determining the metallurgical treatment. With one or two exceptions the minerals noted are of relatively high specific gravity, and the ore as a whole is exceptionally heavy, many determinations giving an average specific gravity of 3.00. This high specific gravity presents one decided advantage, when the' cost of treatment is compared with operations elsewhere, in that the ton, almost universally the basic unit, represents a volume probably less by 10 per cent. than that of many gold ores. On the other hand, this high gravity renders more difficult the discharge of pulp from mortars, its distribution on amalgam tables, and its transportation in launders.

Jan 7, 1915