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By Charles Kumke

THE "slot" system of mining in use at the Golden Queen mine, Mojave, Calif., does not involve any new mining methods. It is, how-ever, a, new combination and adaptation of several stoping systems in common practice. The first plans for stoping operations at the Golden Queen mine called for ordinary shrinkage stopes. The hanging wall of the vein, where exposed, is a very hard felsite with a dip varying from 50° to 70°. The vein itself is quartz, shattered and fractured enough to make it easy to drill and blast to a clean hanging wall. There is no well defined footwall. The footwall limits had to be determined by assays as the metal content faded out into the felsite. Two shrinkage stopes, each approximately 200 ft. long, were laid out and started on the 200-ft. level. One of these stopes, varying in width from 8 to 18 ft., was carried on up to the top limits of the ore, approxi-mately 120 ft., without a break in the operation. The shrinkage system proved entirely satisfactory and low costs resulted from-this operation. In the final drawing of this stope, two timbermen followed down on the ore, scaling the hanging wall clean of small fragments and placing an occasional long stull from foot to hanging wall where it was deemed necessary. Few such stulls; however, were required. The hanging wall stood up very well until the stope was entirely emptied of ore. Waste fill was then put into the stope by the glory-hole method, through a waste raise that had previously been run to surface from the middle of the stope. The second shrinkage stope ran into difficulties about 35 ft. above the sill floor. Up to this point the maximum width of the ore had been about 15 ft. The ore suddenly widened into the footwall to a distance of 40 ft. in the north end of the stope. In extending the stoping operations over this width, it was soon found that the vein material would not arch and support itself. Drilling in this end of the stope was then entirely too hazardous, and all operations were stopped. The ore was drawn through the chutes below as rapidly as possible and as soon as the stope was entirely

Jan 1, 1937

By S. Shapiro, G. Krauss

We will reply to Dr. Pitsch's discussion by 1) presenting in greater detail the single surface trace analysis which we performed on the reversed austenite plates in a single parent plate of martensite of known orientation, 2) relating the results of our analysis to the conclusions which Dr. Pitsch makes on the basis of our data, and 3) examining the validity of our selection of twenty-nine individual traces from the over 200 austenite plates which were observed in a surface of this single martensite plate. Fig. 7 shows a standard (001) projection of the martensite plate from which the austenite-martensite interface traces were taken. The traces are plotted on the projection as the small solid circles, and the great circles corresponding to the loci of plane normals which could contain each trace or could intersect the surface plane along the measured directions are also plotted. It can be seen that these great circles intersect at a point which corresponds to the normal of the surface plane on which the traces were observed. Also rate which occurred only at particularly low heating rates, see Figs. 1 and 3 in the paper.2 Since in this case the interpretation of Jana and Wayman is plausible and since we have no alternative to this interpretation, we would like to state only that the existence of a diffusion-controlled reversal at low temperatures seems to be not yet proved beyond any doubt. The author wishes to thank Professor G. Krauss for making available his manuscript prior to publication. It is also a pleasure to acknowledge the lively written discussions, which the author has had with Professors G. Krauss and C. M. Wayman prior to this communication. The financial support of the Deutsche For-schungsgemeinschaft for the work on which this communication is based is also gratefully acknowledged. plotted within small dotted circles which represent a i3 deg scatter in each of the twenty-four unit stereo-graphic triangles are our A and B poles7 and the pole P determined by Kessler and itsch.' The data presented in Fig. 7 permit a direct association of the measured traces and the various proposed habit plane poles for the reversed austenite plates in the martensite crystal. If the sample measurements do in fact

Jan 1, 1969

R. B. BRinsmade, Ixmiquilpan, Hgo., Mexico (written discussion").—how far ahead of the United States are the self-governing British colonies in their application of economic democracy is well illustrated by Mr. Godson's paper. To prove this, I need quote only two of his assertions, the italics being mine: "lt is a stern fundamental principle that a11 natural resources are the inalienable property of the crown.'' "The right to a claim should only exist as long as it is worked or taxed to insure work. Once depart from that sound maxim, there results improper control of the natural resources of the country, which primarily belong to the people." These assertions formed the basis of my criticism1 of Dr. Raymond's paper in 1913, and they should be inscribed in letters of gold above the entrance to the office of every county recorder in the United States. I venture to assert that the existing United States mineral land laws are essentially unfair to the nation and a hindrance to the legitimate miner, because they fail to embody the above quoted principlca; and this applies both to state laws east of the Mississippi and to federal laws in the West. That these laws favor the forestaller and the monopolist, defraud the government of its fair share of the profits of mineral production, and tend to industrial feudalism must be evident to any competent unbiassed observer. The fact that no serious political movement arose to change them, until the conservation agitation of the last decade, may be largely explained by two salient conditions. First, as stated by President Winchell, "for a long time there was such a vast surplus, or excessive amount of unwanted, undesirable land in the West that the land offices did not scrutinize the claim sought to be located;" second, that the millions of individual farm owners throughout the country could easily be aroused, by the special pleaders hired by the great land speculators and monopolists, to use their vast political power for the suppression of any statesmen striving to incorporate in our semi-feudal land laws any such principles as those quoted from Mr. Godson. While agreeing with Mr. Godson that a freehold or fee-simple title, if coupled with obligatory continuous work, may have the same practical effect as a lease, it seems to be the experience of the most active and

Jan 1, 1920

By C. A. Hartnagel, D. H. Newland

The market for Pennsylvania grade showed a drop both in demand and in prices, which reacted unfavorably on New York oil production, all of which comes under that classification. The output for the year in New York amounted to 5,045,200 bbl. The production in 1937 was 5,478,000 bbl., the largest in any year for the last half century or more. Falling prices, of course, affected new drilling. They declined from $2.20 a barrel, which was posted at the start, to $1.68 in the final months of 1938. With this came a reduction in the amount of oil that would be accepted by the refineries operating in the New York fields. Conditions therefore have combined to halt, at least temporarily, the growth of oil production in the state, which had experienced a steady gain for the last 15 years or more, the yield having risen from less than 1,000,000 bbl. to the round total of 5,500,000 bbl. in 1937. Practically all the oil now obtained is from old, developed fields. No new pools have been found in the last quarter of a century or more. The larger share comes from flooding the sands. Although there are many wells that still produce without the aid of the water drive, they are small and for the most part are pumped periodically. Of late, new drilling has been restricted mainly to that required to maintain existing flood projects. Because of the high initial cost and time required to put a flood into production, the depressed condition of the market has been a serious handicap financially, and, further, has been an unfavorable influence on the planning of operations to secure the maximum recovery of the oil. Unless market conditions improve, it is certain that the effects will be shown in the yield for some time to come. Gas Developments Drilling was active in the southwestern area, chiefly in Allegany and Steuben Counties, and some notable wells were brought in that tapped the Oriskany sandstone. Altogether 42 holes were put down in the two counties, of which 31 were listed as producers and 11 were dry. The new wells gave an initial daily flow of 239,000 M cu. ft. At the close of

Jan 1, 1939

By W. L. Zeigler

THE tailing from the gravity concentration plant of the Hecla Mining Co., Gem, Idaho, was former-ly loaded into railroad cars to be used for ballast, highway surfacing material, or concrete work, or dis-posed of by an aerial tramway, which dumped it into another gulch. The tailing averages about 1.2 per cent lead and 0.8 oz. silver to the ton. Further treatment for the recovery of the valuable metals had been investigat-ed several times with results that did not warrant the construction of a retreatment plant; but early in 1925 experimental work was again started with small tests, and later with a 10 tons per day flotation test plant. This showed that the tailing could be ground and treat-ed by flotation at a profit. It was decided to make the new flotation plant an addition to, rather than incor-porate it in the old concentrator, the original capacity of which had been increased many times, the present arrangement being by no means ideal. The old mill buildings were of timber and board contruction, creat-ing more or less fire hazard, so all new construction was made fireproof. Construction work on the new plant was started in the middle of July, 1925, and the plant was placed in operation early in December. The building is of concrete and steel with hollow tile walls, steel sash and corrugated asbestos roofing. The ball-mill floor has for its foundation a cellular reinforced concrete block about 14 ft. deep, extending to cemented river gravel, and the cells filled with tailing to give weight to the block. Overhead, built into the steel frame, is a 5-ton hand-operated traveling crane. With both ball-mills running fully loaded, there is not the slightest trace of vibra-tion in the foundation or building. The flotation floor is of reinforced concrete beam construction and spans Canyon Creek. Adjustable plunger feeders are arranged under the the tailing-bin, which feed by gravity to a 14-in. eleva-tor, discharging to a short 18-in. conveyor. From the conveyor the tailing is discharged into a dividing hop-per, from which point the plant is arranged in three separate units. Each unit consists of a ball-mill in closed circuit with a classifier, and an 8-cell flotation machine and has an approximate capacity of 300 tons per 24 hours.

Jan 8, 1927

By H. F. Seifert

THE classification and preparation of non-ferrous scrap metals is a subject of interest to every individual and corporation that employs in its processes of manufacture non-ferrous metals and alloys and accumulates in such manufacture scrap from these materials for disposition in the form of turnings, borings, short ends, punchings, clippings, grindings, washings, etc. All too frequently the disposition of such scrap is left to individuals who have no knowledge of the subject either from a metallurgical or a commercial standpoint, or both. Much money is thus lost which with a little more intelligent effort might be saved, and in this day of fierce competition and small profits such an opportunity cannot be ignored. The Mineral Resources of the United States for the year 1925, the latest issue available (Part 1, page 221), gives the secondary non-ferrous metals of certain classes recovered in the United States for the year 1924 to 1925 as shown in Table 1. The figures are tabulated simply to give the reader some idea of the scope of the secondary non-ferrous metal industry. Approximately 900,000 tons of an annual value of $244,000,000 were recovered in the year cited. In 1916 (again using the Mineral Resources of the United States as authority) the tonnage reclaimed was approximately 632,000 tons and the value, because of the high prices for metals prevailing at that time, amounted to $265,000,000. It is not the purpose of this paper to discuss smelting and refining operations or the feasibility of an organization, primarily engaged in some other activity, conducting smelting and refining operations to convert its own non-ferrous scrap metals and alloys. The classification and preparation of these non-ferrous materials is a preliminary step, regardless of what subsequent operations the material may pass through or where these operations may be conducted. For that reason the subject can be readily discussed without any reference to subsequent activities. Space must be provided, with suitable handling facilities, scales and the necessary storage bins where the material may be accumulated. The scope of the activity, the nature of the industry and the tonnage handled will determine, in a large measure, what preparation, if any, it may be desirable to give these scrap materials to put them in the best marketable condition. By preparation is meant largely what, for the want of a

Jan 1, 1928

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

By Alexander Deussen

The figures listed in a table for Gulf Coast fields given by L. P. Teas1 in 1934 are so greatly at variance with results that I have obtained from a serious study of this subject over a number of years, that I am disposed to challenge the correctness of Mr. Teas' figures as an accurate representation of acre-foot yields of Gulf Coast fields, and as regards at least two of the fields listed by Mr. Teas I desire to "put into the record" some figures that, according to my study, are more nearly in accord with what I conceive to be the actual facts. Upon investigation I find that Mr. Teas' figures, inadvertently no doubt, arc not what they purport to be. Apparently the figures were arrived at by considering as thickness of the producing formation the net thickness of producing rock corresponding "to the total of the net portions of the producing zones which actually yield oil into the drill hole"—and in following this method I am under the impression that Mr. Teas was acting under instructions of the Institute in the preparation of this paper, in order to get comparable figures from the several fields of the United States. Apparently the author interpreted these instructions to mean that in the absence of cored thicknesses of producing horizons the actual number of feet of screen set in the various producing zones was to be taken as the basis for arriving at the thickness of these zones and the "acre-foot" yields. It is obvious that in many instances only 20 ft. of screen, or even 10 ft. of screen, might be set in a well, when there might be actually 100 ft. of oil sand present. In the early operations in the Gulf Coast it was usual to set much less screen than the amount of sand. It follows that the "acre-foot yields" so arrived at would be much greater than those found by using the full amount of sand. In Mr. Teas' table, it was indicated that up to the end of 1933 "acre-foot" yields had been obtained in the several fields as listed in Table 1. A casual inspection of these yields will show that certainly they do not properly reflect the amount of oil produced from an acre-foot of the

Jan 1, 1936

IN order not to deviate from the proposed order both in speaking of melts and of things necessary for guns, I shall tell you at present the method by which iron balls are made. This is surely a very fine invention and a horrible one because of its very powerful effect. It is a new thing in warfare,* because (as far as I know) iron balls shot from guns were never seen in, Italy before those that King Charles of France brought here for the conquest of the Kingdom of Naples against King Ferrandino in the year 1495. Now, although I spoke to you briefly of these when I told you above of the purification of iron, it seems to me necessary to show you again in more detail here how they are made. Therefore I tell you that in addition to iron, bellows, blast furnace, and charcoal, it is necessary to have the moulds, without which they could not be cast. At first, when this work was begun in Italy, it was customary to make these moulds of bronze so as not to be obliged always to be making them of clay. Now the present masters cast the moulds of the same iron in order to save expense. Although I am aware that you should already know how to make these from the methods of moulding taught you before, still I shall tell you the method that is followed in making these, because in the practice of every particular thing there is some divergence from the general procedure. For these balls, first make a ball of wood or of clay, or have one made of lead or iron, round and of exactly the dimensions that you wish. This is if you wish to make only one in your mould; otherwise take as many as you wish it to contain. Bury half of this, or these, in a board or in clay and, having greased them with oil or lard, make a mould over them of plaster of Paris, or of clay if you have no plaster, exactly as you wish it to be in iron or bronze. Then make the other half opposite this. After having taken out the balls make little openings for the gates and vents and like- wise four holes for pegging the parts together. At the back make a stud or

Jan 1, 1942

Discussion of the paper of W. C. PHALEN, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2249 to 2265. DAVID T. DAY, Washington, D. C.-Consider the United States broadly and the distribution of the salt industry. Think of the old solar-evaporation process up in New York State, then of the more recent processes in Michigan and Kansas and Louisiana, where the rock salt furnishes a large industry, then of the solar-evaporation process at Salt Lake, then turn to the crucial place in the United States, where there is an embarrassment of salt, and that is California. I am not forgetting' the immense body of salt east of that in the Virgin River country of Utah; but in California the situation is interesting. There are very large quantities of salt in the Searles Marsh region; again, in Southern California, at the southern end of Death Valley, there are two or three mountains of salt which have been explored recently, where the salt is sufficiently pure to be used at once. There is also a large deposit of gypsum, and it would be possible there, by extremely cheap means, to produce an amount of salt sufficient to furnish the United States' greatest needs. The principal reason that capital has been deterred from developing such a large mass is not the fact that solar evaporation produces a great deal of salt around San Francisco, but the fact that if potash salt is to be produced in connection with the salt in the borax region a, great deal of ordinary salt must be disposed of. It cannot be dumped, for it would get back into the brine again; the first rains would bring that salt back into solution again. It must be sold, given away, or hauled to a distance, which would mean a considerable freight charge. The salt will be going begging. E. G. SPILSBURY, New York, N. Y.-The remark of Dr. Day's regarding the likelihood of the production of a large amount of waste salt brings to my mind the condition that obtains in Germany in all of the potash fields. In Germany salt is a government monopoly. In the development of the potash deposits, it becomes a grave question as to how much salt they may be allowed to extract and bring to the surface.

Jan 4, 1915

By R. H. Sweetser

The Committee on Evaluation of Coal for Blast-furnace Coke reports progress in the working out of the problem of evaluation. There has been no full meeting of the Committee but there have been several conferences with two or more of the members present, and the different members have expressed themselves freely on the five points that have been under consideration since the meeting of the Committee in New York on Feb. 16, 1932. The need of a method of coal evaluation, not only of coking coals but all other kinds, is obvious. Under NRA it becomes imperative that coals of the same size from the same seam be priced according to their variations in quality, especially in reference to cleanliness in respect to freedom from extraneous ash-forming materials. In looking over the correspondence that has passed between members of our Committee, it is evident that much of the confusion and misunderstanding would disappear if we could realize that practically all of the variations in value of coal from the same seam of coal are due to variations in the amounts of extraneous materials that are contained in the coal as it passes over the scales for shipment. It is not now a question with our committee as to the differentials in value, or in prices, between different kinds of coking coals or between noncoking and coking coals; our present problem is to arrive at the method for determining the scale of values of the coal from a certain coal seam according to the increase or decrease of extraneous ash and moisture from a predetermined base line adopted for that particular coal. The five points mentioned above are the same as discussed at the meeting in February, 1932, except that the temperature for determining the moisture content has been changed from 212" F. to 221" F., at the suggestion of Dr. A. C. Fieldner. The points are: 1. It is proposed that the coal industry adopt as a base line for evaluating all coals the analysis of the coal as it passes over the neighing device that determines the tonnage of coal bought and sold. 2. It is proposed that the Committee on Evaluation of Coal for Blast-furnace Coke approve the adoption of the base line for Pittsburgh seam coal presented by F. A. Jordan at the annual meeting of A.I.M.E.

Jan 1, 1934

By Will Mitchell, T. G. Kirkland, C. L. Sollenberger

R. S. Handy (Santa Rosa, Calif.)—It would be interesting to learn the comparative results of treating the Korean scheelite ore described in this paper according to the following procedure: I—Follow the procedure described in the paper to the recovery of the sulphides by flotation. 2—Dilute the residue from the sulphide flotation strongly with water and disperse the contained colloids by adding a mixture of 75 pct sodium silicate and 25 pct quebracho to dispersion point. 3— Settle the dispersed pulp and decant the supernatant colloids. 4—-Dilute, settle, and decant the pulp until the settled residue is crystalline. Not over 10 pct of the tungsten minerals should follow the colloids. 5—Treat the settled residue by flotation, having established the proper pH. Oleic acid homogenized with cresylic acid or kerosene is more selective for scheelite than is oleic acid alone. (The recovery of the contained tungsten minerals should be practically complete in this operation.) 6—Deflocculate the tungsten concentrate from step 5 with the same dispersion agents as in step 2 and treat the deflocculated pulp by gravity. The minerals that tend to float with scheelite are generally of low specific gravity and the separation is efficient. The heavier contaminants, such as pyrrhotite and magnetite can be removed magnetically, leaving a practically pure scheelite. E. J. Pryor (Imperial College of Science and Technology, London)—It occurred to me that instead of using temperature as a differentiating control, more precision might be obtained with a reagent of a type we developed here for the flotation of high grade fluorspar in cold pulps. This reagent, which is manufactured on a modest scale in England, is based on oleic acid, which has been modified by our patented process to ensure complete stable dispersion at any desired concentration in water. It thus becomes possible to utilise unimolecular layers with good selectivity. In the fluorspar flotation for which we developed it, it is possible to hold a tight control on depressing quebracho for the calcite without substantial loss of flu-orite, and recovery exceeding 99 pct is not uncommon in the mill where it is in use, even under wintry conditions. No attempt has been made yet to extend the use of the reagent, as we have not completely overcome

Jan 1, 1952

By James A. Beck

Phosphorus is essential to all life processes and therefore to the existence of man. In this role, there are no substitutes for phosphorus. In a commercial sense, phosphorus and its compounds are important to our entire economy, both in agricultural and in nonagricultural applications. The world's phosphate requirements are met by mining phosphate rock. Two general types of phosphate ore deposits are commercially important-igneous and sedimentary. Igneous deposits generally are more difficult and more expensive to mine than sedimentary deposits and are of importance mainly in the USSR, North Vietnam, and South Africa. Approximately 15% of current world production comes from these deposits. Over 80% of world production is from the pellet sedimentary deposits of Florida, North Africa, and elsewhere. Guano, the second type of sedimentary deposit, is produced in South America but is declining in world importance. Production Production of phosphate rock was reported in 31 countries during 1972. However, about 80% of world output is produced in three countries: the United States, the USSR, and Morocco (Table 15.2A.1). Throughout the past 20 years, between 75% and 80% of world output has been produced by these three leading countries. Between 1948 and 1972 world production increased at an average rate of 10% per year, from 21.5 to 103.9 million tons. Growth was quite steady at 6% per year through 1963, but in the 5 years from 1963 to 1968 production increased 11 1/2% per year. Since 1968 production has increased about 91/2 % annually. Since 1948 several new phosphate mining ventures have been developed in Senegal, Togo, Israel, and North Vietnam. In the same period, only one important phosphate deposit, on Makatea Island, has been mined out and closed. A number of other phosphate mining ventures are in various stages of planning and development. The most important new venture in phosphate mining is in the Spanish Sahara. New mining capacity is expected also in Syria, and serious investigation is in progress in Peru, India, Turkey, and Australia. Major expansion of existing operations is expected in Morocco, Russia, Tunisia, Israel, and Jordan. Consumption Historical data on world consumption of phosphate rock are not available in detail, but world consumption of phosphate has closely paralleled world production in the past two decades. The United States is the world's largest user of phosphate rock, accounting for 30%

Jan 1, 1976

By John Birkinbine

(Read at the Philadelphia Meeting, February, 1878.) IN a former paper* attention was directed to the various firms of pumping machines employed for permanent work in mining and metallurgical processes. The following is simply a collection of memoranda of work done of a temporary character, and is presented by way of comparison with other work of similar nature. In close proximity to the charcoal furnace at Pine Grove, Cumberland County, Pa., is a large deposit of superior hematite iron ore, which has been worked for a number of years, and from which many thousand tons of ore have been taken by open pit workings. In July, 1874, the furnace was blown out and operations at the bank suspended, the machinery for draining being removed except a plunger pump, 18 inches in diameter and 66 inches stroke, operated by a steam-engine by means of rods. The pit was allowed to fill with water, and no steps towards its reclamation were taken until November, 1877. At that time the pit was a pond of water at the base of the mountain, having an area of about four acres and a depth of seventy feet. As the pumps, rods, etc., had been submerged for over three years, and partially buried by the mud washed down from the banks, and as it was determined to change the location of the pump for future operations and drive it by water-power, a temporary pumping apparatus was determined upon for reclaiming the pit and keeping it drained until the permanent arrangements could be completed. By opening an old adit about 10 feet of the water was removed, and the area decreased to three acres. The inflow of springs was found to be 250 gallons per minute, and the amount of water contained in the pit was computed to be 45,000,000 gallons. As the inflow would undoubtedly increase while the water sank in the pit, provision was made for removing at least 60,000,000 gallons, at the rate of 1,500,000 to 2,000,000 gallons per day. The company determined to employ a Heald and Cisco centrifugal pump driven by an oscillating engine by means of a belt. Steam was supplied by four plain cylinder boilers, each 36 inches diameter *Transactioiis of the American Institute of Mining Engineers, vol. p. 455.

Jan 1, 1878

Discussion of the paper of J. K. FURST, presented at the Pittsburgh meeting, October, 1914, and printed in" Bulletin No. 94, October, 1914, pp. 2493 to 2514. W..McA. JOHNSON, New York, N. Y.-On discussing this paper I am open to the criticism of "bringing coals to Newcastle," as I, a zinc man, am bringing new ideas on steel to Pittsburgh. But still the view of an outsider can be valuable to the insider. Any multistage process, where each apparatus operates on its particular part of the work at a high efficiency, constitutes an advance in the state of art. But in multiplicity there can be complication and ensuing loss and inefficiency. The duplex steel process is not the pronounced success which was predicted for it by its adherents, for several of such plants have reverted to plain open-hearth methods. If we regard broadly refining processes, such as the Bessemer, open-hearth, puddling, copper refining, lead cupelling, nickel refining, we find that in general refining processes are intermittent and 'concentration processes are continuous. (This generalization I believe to be original with me; it was communicated to Dr. E. F. Roeber, editor, and appeared as an editorial in Metallurgical and Chemical Engineering, March, 1905.) Where we desire primarily quality in a metallurgical operation we must put a batch of metal in the furnace, work on it until we get it to the required purity, test it, and take it out; whereas, if we desire primarily quantity we shove ore into a furnace and smelt it as fast as possible, allowing conditions to make a non-uniform product provided only we get tonnage. From general commercial principles, I believe that the weak point of the duplex process is that the operation is not a money maker unless the plant is kept at. 90 to 95 per cent. of its rated capacity, or unless the Bessemerizing is done so often that it is practically continuous. For in some manner the operation should be made continuous and the control on the tonnage should be commercially flexible. The commercial rigidity of having to control purity exactly increases operating costs without a corresponding gain. Conversely, the chief reason for failure of "steel from ore direct" is that it makes a final operation continuous, which should be naturally intermittent.

Jan 4, 1915

By A. R. Ledoux

I was wondering whether we were going to adhere to our text. It seems to me that we are having a very remarkable meeting of mining engineers this year, because no matter what the texts may be that are assigned to us, we get back toward something higher; we turn to the consideration of questions of ethics, and of applied Christianity. Yesterday we listened to the most eloquent and remarkable address by Mr. Rickard in memory of Dr. Raymond, and it was told us that he was to speak about Raymond's achievements as an engineer. He did say considerable on that subject, but he was himself carried away with the spirit of the man and moved us all by his portrayal of Dr. Raymond's continued and fruitful labors for the betterment of mankind—that is to say, his religion. Our President asked me if I would say something this afternoon and I find in the bulbtin that the text of the discourses which we are to have here this afternoon is "Internlttional Cooperation in Mining in North America." But again I find that the eloquent speaker who has just preceded me has dwelt largely on ethical and spiritual cooperation rather than upon cooperation in mining. That is, cooperation as men, rather than solely as engineers. The imaginary line dividing Canada from the United States, unmarked by fort or military post, was mentioned by a previous speaker. There are going to be in the future, I am sure, fewer entanglements of the barbed wire of tariff discrimination along our border-—to that end let us cooperate. But there has always been a reciprocity in men. A Canadian conceived and created our great transcontinental line, the Great Northern Railway; an American made the Canadian Pacific what it is. In mining and metallurgy, American engineers, backed by American capital, have built up great Canadian industries while Canadian experts have developed some of the resources on this side of the line. They have done much more than develop our resources; some of them have been our leaders in sympathy for labor. It is therefore not a question of creating a spirit of cooperation, but of giving it freer scope and a fuller realization of fraternity—or, to use the word now more common and of deeper significance—brotherhood. These are days of combination. Corporate interests in this country are now compelled, or at least encouraged, to combine in ways that

Jan 1, 1920

By C. Y. Garber

INTEREST in the sink-float plant operated by the Bunker Hill and Sullivan Mining and Concentrating Co. at Kellogg, Idaho, has recently been largely confined to the preparation and reconditioning of the galena medium. The ease and simplicity of these operations in a concentrating mill producing a flotation lead concentrate has occasioned enough comment to possibly justify a brief description. The subject is treated from an operator's viewpoint only; no effort is made to discuss it in a theoretical or technical manner. PLANT AT BUNKER HILL The sink-float plant was first operated in December 1941. It was built for the purpose of quickly increasing mill capacity with a minimum of equipment. It is the Huntington-Heberlein sink and float process using galena medium and is operated under license from the Sink and Float Corporation, New York city. Lead-zinc ore from the Bunker Hill mine is crushed to pass a I ¼ in. screen and is then washed and separated on vibrating screens having 4 ½ -mm. round-hole punched plates. The screen undersize, amounting to 33 per cent of the mill feed, is dewatered and sent to the ball-mill feed bins. The screen oversize goes to the sink-float plant, where 50 per cent of the oversize, or 33 per cent of the mill feed, is float, which is washed free of medium and disposed of as a tailing. The remaining 33 per cent is sink, which, after washing, is crushed to pass ½ in. and joins the undersize in the ball-mill feed bins. The normal plant capacity is 1700 tons per 24 hr. About 1.7 per cent of the total lead and 3.3 per cent of the total zinc in the feed is lost with the sink-float tailings (Table I). [ ] More complete descriptions of the H. H. process and Bunker Hill sink-float plant are given in several recent articles, listed at the end of the paper. PREPARATION OF MEDIUM AT BUNKER HILL New medium is made intermittently as needed, usually 12 hr. in each 6 days. A small portion of the current mill flotation concentrate is diverted from the lead cleaner cells to a I-in. vertical sand pump and pumped to a two-cell 36-in. Agitair flotation machine, where NaCn and ZnSO4 are added and the grade of concentrate is improved as shown in Table 2. Tailing from this operation is returned by gravity

Jan 1, 1946

By J. T. Brown

AS far as could be ascertained, no one had previously investigated the creep strength of silicon poly-crystals. Literature has appeared showing evidence for plastic deformation in silicon single crystals and whiskers.*1"6 Also the fact that germanium, a material of similar crystal structure to silicon undergoes plastic deformation under stress at temperatures above about 60 pct of its melting temperature, has been known for some time.2"4'7 This investigation was performed for the purpose of determining the strength and ductility of silicon polycrystals under creep conditions that would give fairly long times to rupture. PROCEDURE The silicon specimen blanks were obtained by first placing granulated transitor grade silicon (99.999 + pct pure) in a silica crucible. The crucible was surrounded by a graphite susceptor, and induction heating was used for melting the silicon in a vacuum furnace. Blank specimens were formed by freezing molten silicon onto a polycrystalline seed of silicon in a vacuum furnace. The seed was attached to a motor driven revolving rod. As silicon solidified, this rod was gradually withdrawn from the melt. A shape with a contracted center section was obtained by varying the rate of withdrawal from the melt. Specimens for the creep-rupture tests were ground from these "pulled" blanks. Creep-rupture tests were performed in spring loaded machines under constant load at 1800" and 2000° F. RESULTS AND DISCUSSION A test specimen which was sectioned longitudinally is shown in the photomacrograph in Fig. 1. Very little deformation has taken place in the portion of the specimen shown, however, slip lines from several slip systems within the same grain, and deformation band formation was seen. The elongated appearance of the grains is due to the method of growing the specimens. One of the most interesting aspects of the results obtained from the creep-rupture tests was the high strength and the accompanying large amount of ductility. The data obtained is listed in Table I which shows the stress to rupture in 100 hr at 2000°F is between 8000 and 9000 psi. This indicates that silicon's strength at 2000°F is about equal to that of the best commercial super-alloys. It is important to mention that silicon has less than 1/3 the density of iron-, nickel-, and cobalt-base alloys. The usual type alloys for high-temperature applications

Jan 1, 1960

By John M. Hartman

The high temperature of the blast of modern furnaces renders it desirable that the pipe conveying the blast into the furnace crucible shall transmit and radiate as little heat as possible. To accomplish this, the pipe shown in the accompanying sketch was devised and patented. It consists of a slide-valve, leg-pipe, and belly-pipe, which are held together and to the tuyere by a system of levers and links. The slide-valve is superior to the old throttle-valve. The legpipe is formed of two thicknesses of wrought-iron pipe, with a space of half an inch filled in with clay and brick. The belly-pipe is made in the same way as the leg-pipe, and terminates in a globe face to suit the tuyere. The quarter turn is made extra thick, of cast iron, and the cap on the end is lined with clay also. The catches, A, B, C, are merely for convenience in putting the pipe together. The joints D and E are globe faces, and allow the pipe to adjust itself to any angle. The eye-piece is made of violet glass, which cuts off the glare from the bright coals in the furnace and allows a close examination of the interior, so that any water dropping or vapor can be detected. The glass does not become coated with dirt, like mica. Since good running of furnaces is shown by a bright tuyere, it is necessary to have a good eye-piece to examine them. To detach the pipe, a man lifts the weights, the side rods are then slipped off the bell crank under the quarter turn, the link under the belly-pipe is unhooked, and the pipe carried away. The same process is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the nozzle through the belly-pipe, and inserting another. In this way the change can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, which burned up and gave trouble. In other cases key-bolts were used, making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for movement from contraction or expansion. As the temperature of the blast increases there is more expansion, and where rigid joints are

Jan 1, 1879

By Lester Guttman

THE connection between short-range order and thermodynamic activities in binary solid solutions has been pointed out by Birchenall1 who calculated approximate values of the energy of interaction of Zn and Cu and of the degree of short-range order in alpha-brass at one composition and two temperatures. The purpose of this note is to call attention to a somewhat more accurate theory than that used by Birchenall and to extend the calculations to a wider range of temperatures and compositions as a means of testing its applicability. This is an example of the well-known general method of comparing measured thermo-dynamic functions of a system with those calculated from a microscopic model by means of statistical mechanics. In this case, mathematical approximations must be used which make difficult any decision about the validity of the model. Birchenall's statistical method resembles closely that called by Fowler and Guggenheim2 the "quasi-chemical" method which has been shown to lead in certain cases to results identical with those obtained by the method of Bethe.3 The quasi-chemical method has been extended by Takagi4 to give general formulae for the free energy of binary solid solutions based on several lattices at all compositions and temperatures. Specifically, he treats the four systems typified by: I. ß-brass; 2. a- brass; 3. AuCu3; 4. AuCu. When the temperature is so high that no long-range order exists, these formulae reduce to the same form for all lattice types, namely: [ ] Here the symbols have the following meanings: [F-Helmholtz free energy E-energy S-entropy k-the gas constant per molecule z-coordination number, (e.g. 12 in. a-brass). N-total number of atoms c-atomic fraction of A] VAA, VBB, VAB-energy per bond of the corresponding bonds log means log, throughout The superscript 0 denotes the thermo- dynamic function in the standard state, which has been chosen to be pure A or B with the same crystal structure as the solid solution. The quantity x is the ratio of the number of A-A bonds to the total number and for minimum F satisfies the equilibrium condition [ ] The free energy may also be written in terms of µA and µB, the chemical potentials or partial free energies per atom:

Jan 1, 1948