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By MORTON WEBB

Discussion of the paper of Max Boehmer, presented at the Pittsburg meeting, March, 1910, and printed in Bulletin. No. 38, February, 1910, pp. 119 to 122. W. MORTON WEBB, Germiston, Transvaal, South Africa (communication to the Secretary*):-The experience of Mr. Boehmer in the Leadville district and his reputation as an engineer assure the interest of anything he may write on the ore-bodies of that district; and all engineers who have operated in Leadville will agree that the theory of the origin of the Leadville deposits, as given by Mr. Emmons in his famous monograph, does not adequately explain the genesis of all the deposits. The solution of the problem does not, however, appear to be quite so simple as Mr. Boehmer would make it; and the advance pamphlet issued by the U. S. Geological Survey, pending the completion of the main report, shows that there is still much ground for controversy. No doubt the later eruptives had a greater influence on the deposition of the ore-bodies than was thought at the time of the first investigation by the Survey; but it has always appeared to me that the influence exerted by these dikes was more in the nature of a physical than a chemical one. The weight of evidence in recent years is mostly in the direction of ascension rather than lateral secretion; and one of the strongest evidences is the fact that most of the ore-bodies lie under one of the comparatively impervious layers which help to make up the structure of these hills. On Iron hill I have found a very persistent white porphyry sheet, split off from the overlying porphyry and lying from 30 to 60 ft. below the main white porphyry and blue limestone contact. This sheet varies from a few to 50 ft. in thickness, and where found adds another "contact" to that region ; some of the largest ore-bodies on Iron hill lie immediately under this sheet. Above this is the main white porphyry and * Received Mar. 3, 1910.

Feb 1, 1911

By E. J. MCOAUSTLAND

THE behavior of steel after overstrain and at moderate temperatures is fairly well known. It has been made the subject of much investigation, and our knowledge is clear and definite on many points. The ultimate raising of the elastic limit, after moderate overstrain, and the consequent lowering of the ductility, seem to be well established. It is also well understood that the immediate effect of overstrain is to lower the elastic limit, possibly to zero, but that if not interfered with, this limit will subsequently rise higher than before. The "tests after moderate temperature," reported in this paper, were undertaken to verify the above statements for the particular steel under investigation, and also to determine, if possible, the total time required for complete recovery from this state of overstrain. The behavior of overstrained steel at temperatures at or below 32° F. is not so well known. Tests made by Prof E. G. Coker, at McGill University,' show that steel, overstrained and subjected to cold, will remain in a state of overstrain for an indefinite period. I am not aware of any other published results of tests along this particular line. The effect of time and temperature on the recovery of steel from overstrain was made in 1902-3 the subject of sortie investigation in the laboratories of the College of Civil Engineering of Cornell University. A general plan was outlined in connection with the regular courses of instruction in testing of materials; but the press of routine work and the demands of the schedules on the time of the students were so great as to presage long delay in the completion of the work. Not much had been accomplished up to 1904-05, when Messrs. E. C.

May 1, 1906

By E. W. Davis

THE large iron-ore producers on the Mesabi Range are able to maintain the silica in their shipping products at from 8 to 10 per cent by mixing ores of various grades, some assaying 4 per cent silica and some as high as 18 per cent silica. For each ton of 4 per cent silica ore mined, a ton of 14 per cent silica ore can be mined and mixed with it and the average grade maintained at 9 per cent. This mixing operation has made possible the utilization of large cluantities of ore too lean to be used alone. and herein lies the advantage of the producers who operate a number of mines at the same time. As the grade of the ore from one of the properties falls off, a little high-grade ore from another property can be mixed with it and the average maintained, while if one property alone were being operated all of the ore below grade would be left behind.

Jan 1, 1930

By W. L. Zeigler

During the middle 1880's, shortly after the discovery of silver-lead ores in the Coeur d'Alene district of northern Idaho, it became apparent that concentration of the ores would be necessary to obtain a profitable product. Too much siliceous material was present for direct smelting, and the majority of the ores found at depth were too low in metallic content for economic smelting processes at the time. As the ores occurred in quartzite shear zones with siderite and quartz gangue, a large quantity of waste material was present in all the mines. As the galena was not finely disseminated, this made possible relatively good extraction of the argentiferous galena by coarse concentration. The first concentrators consisted mainly of coarse crushing, screening and jigging, principally by Harz jigs, the slimes being treated on buddles. Later Wilfley tables took the place of sand jigs and vanners superseded the buddles. Because of the marketing conditions, no attempt was made until 1900 to effect a recovery on the zinc minerals present, which were found associated in varying amounts with the galena. All through this period, the greater part of the production was obtained from mines containing ore assaying high in lead and low in zinc. Parts of some ore bodies would be reversed in this respect, so that ores high in zinc were left intact. During the decade after 1910, several important mines, The Success and The Interstate Callahan, containing ores high in zinc, were put into operation and were a material aid in the needed zinc production during World War I. Gravity concentration by jigs and tables was used during this period, with bulk flotation increasing in popularity for the treatment of the fine material that had already been treated by ordinary slime concentrating machinery. No extra fine grinding for flotation concentration was thought profitable at the time. Tailings Discharged into Streams From the start of mining and milling operations in this district until 1904, no attempt was made by the various mills in the upper district to impound or stack their tailings. They discharged them directly into the adjacent creeks or streams, to be carried away by high water. The Bunker Hill and Sullivan and the Last Chance mines, both in the relatively flat valley of the district, stacked huge piles of the coarse jig tailings on the near-by river bottom. Rain and snowfall are heavy in the Coeur d'Alene district, as it is on the heavily timbered Pacific slope of the Bitter Root Mountains. A heavy runoff occurs every spring and there is an occasional flood of disastrous proportions when warm "Chinook" winds accompanied by rain

Jan 1, 1949

By Paul T. Benson

MOST important of the various departments of a custom smelter, so far as the financial welfare of the plant and the confidence of shippers are concerned, is that responsible for correct weights, accurate moisture sampling, and the obtaining of control samples that are strictly representative of the lot of ore from which they come. Treatment rate schedules are based on the metal content of ores received, reduced to dry weight. These rates must be low enough to keep the ship- per from taking his business else- where and still must allow the smelter a profit. Assay results, likewise, must satisfy the shipper, but if they show too high a metal content for the ore they represent, the smelter will actually lose money. It is always considered, and constant checks through umpire assays prove, that laboratory results are closely correct, so the bur- den of the plant profit and loss and the satisfaction of the shipper rest squarely upon the sampling department.

Jan 1, 1936

Jan 1, 1887

By Clyde E. Williams

MUCH has been said recently concerning the depletion of the Lake Superior iron ore re- serves. Estimates given indicate a total life of the present known reserves of twenty to thirty years. Some argue that there is no need to concern ourselves about the possible depletion of the Lake Superior iron ore supply because foreign ores can be brought in to this country at a lower price than rich agglomerated ore can be produced from the lean domestic ores. Some fear, as a result of this, a displacement of the steel business from present districts to the Atlantic seaboard. Others show that foreign ores will be brought to interior points via the projected Great Lakes-St. Lawrence waterway. Others believe that the South, given better freight rates, will extend its iron and steel market into northern territory.

Jan 1, 1931

By R. E. Wagner

MISSOURI's famous lead area, in what is known as Southeast Missouri, is locally termed the "Lead Belt." These deposits are in the Bonne Terre dolomite of late Cambrian age which has a thickness of nearly 400 ft. Underlying this is the La Motte sandstone which varies in thickness from 0 to 400 ft. The La Motte beds are deposited directly on the ancient erosion surface of Pre-Cambrian porphyries and granites of probably Algonkian age. The buried igneous peaks extend up into the Bonne Terre in several areas within the Lead Belt. Overlying the Bonne Terre are shales and siliceous dolomites of late Cambrian and early Ordovician age. Within the Lead Belt these have a thickness of from 0 to 500 ft. The district is bounded in general on the southwest by the Sims Mountain fault, on the northwest and north by the Big River fault, and on the

Jan 1, 1947

By G. F. Fix

Oil and gas activity reached a higher peak in Indiana during 1940 than for any like period during the past decade. Major activity, as during 1939, was in the southwestern part of the state, the Indiana portion of the Eastern Interior Coal Basin, where most of the increase was due to field drilling in previously proven areas. The amount of wildcat drilling was about the same as for 1939. No new fields of any apparent consequence were discovered during the year, with the possible exception of the College pool, in southwest Posey County. Only one well had been completed in this area at the end of the year. About 10 ft. of saturated Aux Vases sandstone was drilled in this well and the initial production was I00 bbl. of oil a day. Other discoveries during the year 1940 include: St. Thomas, in southwestern Knox County, where four McClosky wells, ranging from I00 to 300 bbl. a day initially, were com-pleted; Buff kin, in central Posey County, with 11 oil wells and 5 gas wells completed; and new developments in two old areas —Randolph County (part of the old Trenton field) and Gentryville, northwestern Spencer County, where some oil was found many years ago. The St. Thomas field proved disappoint-ing, with very spotty production from the McClosky horizon of the St. Genevieve limestone at a depth of about 1875 ft. The discovery well flowed 362 bbl. a day ini-tially. At the end of the year the field was pretty well outlined by dry holes and some inside locations were dry. The Buffkin pool also proved spotty, with production from shallow Pennsylvanian sands and from the Basal Pennsylvanian Mansfield sandstone, the latter at a depth of approximately I175 ft., with small production from the Cypress sandstone of Chester age. Oil wells in this pool are small, ranging from 25 to 75 bbl. a day. The Randolph County area, on the east side of the Trenton gas field, showed some promise for a commercial gas field, with four completed gas wells having cumulative initial flows of about 1,200,ooo cu. ft. a day. The area appar-ently was not depleted during the Trenton boom at the turn of the century, since casing pressures are about as high as the virgin pressure in the old field. Elsewhere the pressure has dropped as low as 5 pounds. The Griffin field received most of the drilling during 1940, with 163 completed oil wells. This field now covers about 3200 acres on the Indiana side of the Wabash River and is not as yet completely delimited. It produced the major part of Indiana's oil during the year—a total of 3,594,000 bbl. At the end of 1940, there were 253 producing wells in Griffin. New Harmony had five completions for a total of 24. The Rockport field, in Spencer County, continued to be actively developed and had a total of 45 gas wells and 9 oil wells at the end of the year. Oil in commercial quantities had not been found in the field previous to 1940. Total gas production for the year was 394,470,000 cubic feet. In all, 521 wells were drilled in the state during 1940, as compared to 377 for 1939. Of this number 248 were oil wells, 77 were gas wells and 196 were dry. Divided into

Jan 1, 1941

By G. F. Fix

Oil and gas activity reached a higher peak in Indiana during 1940 than for any like period during the past decade. Major activity, as during 1939, was in the southwestern part of the state, the Indiana portion of the Eastern Interior Coal Basin, where most of the increase was due to field drilling in previously proven areas. The amount of wildcat drilling was about the same as for 1939. No new fields of any apparent consequence were discovered during the year, with the possible exception of the College pool, in southwest Posey County. Only one well had been completed in this area at the end of the year. About 10 ft. of saturated Aux Vases sandstone was drilled in this well and the initial production was I00 bbl. of oil a day. Other discoveries during the year 1940 include: St. Thomas, in southwestern Knox County, where four McClosky wells, ranging from I00 to 300 bbl. a day initially, were com-pleted; Buff kin, in central Posey County, with 11 oil wells and 5 gas wells completed; and new developments in two old areas —Randolph County (part of the old Trenton field) and Gentryville, northwestern Spencer County, where some oil was found many years ago. The St. Thomas field proved disappoint-ing, with very spotty production from the McClosky horizon of the St. Genevieve limestone at a depth of about 1875 ft. The discovery well flowed 362 bbl. a day ini-tially. At the end of the year the field was pretty well outlined by dry holes and some inside locations were dry. The Buffkin pool also proved spotty, with production from shallow Pennsylvanian sands and from the Basal Pennsylvanian Mansfield sandstone, the latter at a depth of approximately I175 ft., with small production from the Cypress sandstone of Chester age. Oil wells in this pool are small, ranging from 25 to 75 bbl. a day. The Randolph County area, on the east side of the Trenton gas field, showed some promise for a commercial gas field, with four completed gas wells having cumulative initial flows of about 1,200,ooo cu. ft. a day. The area appar-ently was not depleted during the Trenton boom at the turn of the century, since casing pressures are about as high as the virgin pressure in the old field. Elsewhere the pressure has dropped as low as 5 pounds. The Griffin field received most of the drilling during 1940, with 163 completed oil wells. This field now covers about 3200 acres on the Indiana side of the Wabash River and is not as yet completely delimited. It produced the major part of Indiana's oil during the year—a total of 3,594,000 bbl. At the end of 1940, there were 253 producing wells in Griffin. New Harmony had five completions for a total of 24. The Rockport field, in Spencer County, continued to be actively developed and had a total of 45 gas wells and 9 oil wells at the end of the year. Oil in commercial quantities had not been found in the field previous to 1940. Total gas production for the year was 394,470,000 cubic feet. In all, 521 wells were drilled in the state during 1940, as compared to 377 for 1939. Of this number 248 were oil wells, 77 were gas wells and 196 were dry. Divided into

Jan 1, 1941

By H. C. Babbitt

The Effect of Arsenic.—A question involving the temperature of precipitation of ammonium phospho-molybdate, which was brought to my attention some time ago, led to the following experiment :*

Jan 1, 1893

By Samuel D. Warriner

(Wilkes-Barre Meeting, June, 1911.) THE dealings between concentrated capital invested in the conduct of our various industries and the combinations of labor known as "trade union organizations," have produced not only in the United States, but abroad, many novel methods of negotiation between employers and wage-workers. The size and strength of these organizations have destroyed the personal elements formerly governing the dealings between employer and employee and have produced various forms of trade-agreements now in more or less successful operation. The difficulty, however, has- been to secure consent of both parties to an equitable agreement. For this purpose there have been devised various forms of arbitration, either compulsory under the shadow of governmental legislation, or voluntary by mutual agreement. But these have not been altogether successful from a technical stand-point, for the reason that a compromise has generally been necessary, and in an effort to reach an agreement, terms have been made which have been neither fair nor satisfactory to either of the contending parties. The Anthracite Board of Conciliation represents one of the few thoroughly successful courts for the settlement of trade-disputes, if not the only one which has yet been evolved. The prestige of this board rests upon its successful treatment of the labor-troubles of the anthracite region for a period of more than eight years, and upon the fact that it has been able not only to reach decisions based upon the merits of the controversies, but to enforce its decisions upon both the employees and the employers. It has never been obliged to shape its conduct to secure the consent of the contending parties, and its decisions have been strictly and, in the main, cheerfully observed. The remarkable feature of this board has been that it has

Aug 1, 1911

By L. Dr. Edeleanu

CRUDE petroleum is a mixture of various groups of hydrocarbons and some bodies containing oxygen or sulphur. These constituents possess properties differing considerably one from another and the proportion in which they are contained in the crude oils is also very different. Owing to this complicated composition the practical use of crude petroleum is much restricted. For example it is sometimes used as a liquid fuel. But its employment in this way is uneconomical because various valuable qualities of the individual constituents are not made use of. The rational utilization of petroleum can only be accomplished if the various groups of hydrocarbons are separated. The mixture of hydro-carbons present in the crude oil must be split up in such a way that the hydrocarbons are divided into various groups having certain predominant characteristics and uses. To accomplish such a separation is the aim of the technical refining of petroleum. ORDINARY REFINING BY DISTILLATION AND CHEMICAL TREATMENT Hitherto this has been accomplished by two processes, namely, fractional distillation and chemical treatment of the distillates obtained. Distillation Process The process of distillation consists in the separation of the constituents of petroleum into various fractions, the boiling points of which lie within certain defined limits. The fractions so separated possess certain special qualities in common, which enable them to be applied for specific purposes in practice. For example, we have the fractions known as benzene, illuminating oils, heavy oils, lubricating oils, etc.

Jan 9, 1914

By J. D. Price, W. M. Bertholf

One of the chief difficulties with which the operator of a coal washing plant has been forced to contend is the handling of the very fine coal. First he has the problem of separating the fine coal from washery water. This is usually accomplished by the use of settling cones or Dorr thickeners: in either event the separated fine coal contains a high amount (40 to 80 pct) of water and, somewhat loosely, dependent upon the size of the coal particles present, may be known as sludge or slurry. His second problem is the satisfactory further dewatering of such separated sludge and/or slurry.

Jan 1, 1949

By Carl F. Dietz

(New York Meeting, February, 1912.) THE problem of drying ores is one that most mill-engineers are sooner or later called upon to meet, and it may be timely to point out sortie of the difficulties resulting from such operations from purely a metallurgical and economic stand-point. We mean, in the following pages, to discuss primarily the effect of such operations on. the ore itself, without particular reference to the mechanical or cost features of the subject; That an appreciable tonnage of the ore fed to the usual form of drier, either rotary or stack, is lost, is fairly well appreciated, but we believe that only a few mill-managers know just. what their drier-losses amount to, and we have found that in most cases they console themselves with the fact that the drier-smoke is not very much discolored, and it is generally believed that the draft is not sufficient to carry away more than a. negligible percentage of the values. The drying of ores is becoming an important factor. since the more general application of magnetic, static, and dry-table treatment. Its importance in the field of metallurgical operations warrants a close examination into its effects. This subject has been repeatedly brought hone to us, and while the drier-losses, in every case examined, have considerably exceeded even the most generous estimate, an attempt at a recovery of these values is rarely made. We have found that the losses resulting from drying-operations can be effectively recovered, at a low cost, and believe that the publication of the results of a number of investigations along these lines will be of interest and benefit to the profession at large. To dry an ore quickly and effectively, it must be brought into actual contact with hot gases or air. The rapid drying is effected by the fact that the hotter the gas the hungrier it is

Jul 1, 1912

By Webster, Wm. Reuben

THE greatly enlarged demand for small sizes of seamless copper tube which has recently occurred, due particularly to the rapid growth of the electric household-refrigerator industry, has emphasized the superiority of phosphorized to tough pitch copper for the purpose of producing this commodity. In the manufacture of this material exceedingly heavy reductions by cold drawing are employed, customary practice involving as much as 90 per cent. reduction of cross-sectional area in four runs without intermediate annealing. Although this superiority has long been recognized by tube makers, no quantitative expression of it has heretofore been published. It is believed that the data herewith presented mill serve this purpose. Recent investigators are not in agreement as to the relative mechanical properties of copper containing small amounts of oxygen as compared with copper containing sufficient oxygen to produce that condition known as tough pitch. Hanson, Marryat and Ford1 found that "oxygen has a relatively small effect on the properties of copper." Johnson, on the contrary, states "it cannot be denied that it (tough pitch copper) is inferior to deoxidized copper . . . where severe mechanical manipulation is concerned." These authorities in the reports of their investigations, as might be expected from their conclusions, do not present data of a character requisite to a conclusive determination of the question.

Jan 1, 1927

By AIME AIME

MILLING called for four sessions and a luncheon and covered broad ranges from speculative theory to basic practice, and from coal to gold. An attractive and profitable feature was the "get-together" of "coal preparers" and "ore dressers" for mutual discussion of their common problems. The first event was the Milling Luncheon in the Engi¬neers' Club on Monday. A concentrated group of high¬grade appeared and many matters were discussed, but only two called for official action: The meeting unanimously recommended the use of the Tyler standard sieve scale as against any new scale, and also the adoption of micron designation for fine particles in place of decimals of an inch or millimeter, or theoretical mesh size. The real sessions began on Monday afternoon with a menu of Mineral Physics for the ore dresser, metallurgist, geologist, physicist, et al. Four papers by the staff of the U. S. Bureau of Mines dealt with the chemical and physical aspects of mineral structure as revealed by the first two years of research to date. A fifth paper by Dr. M. J. Buerger correlated to the foregoing the knowledge of "The Lineage Structure of Crystals" and finally a sixth paper was a progress report of further developments of the last year in explosive shattering of minerals by the U. S. Bureau of Mines.

Jan 1, 1933

By T. A. Read, H. K. Birnbaum

Deformation of AuCd alloys having the 8 (orthorhombic) and (3" (tetragonal) structures occurs by the stress induced motion of twin boutdaries. A restoring force acts on displaced twin boutdaries as a result of internal energy increases in the volume through which the boundaries are displaced. The phenomonology of the twin boundary motion is described and a mechanism for twin boundary motion and the restoring force is proposed. A time-dependent stabilization behavior of the twin boundaries, which is observed after the twins are formed by the diffusionless phase transformations, is described. THE AuCd 8 phase (ordered bcc structure) exhibits a transformation to a phase having an orthorhombic structure, 8' (space group D'), for compositions in the vicinity of 47.5 at. pct Cd and to a phase having a tetragonal structure, 8" (point group 4/m, m,m), for compositions in the vicinity 50.0 at. pct Cd. Both transformations are diffusionless, occur on cooling at 60" and 30OC, respectively, and are crystallo-graphically reversible.' They are accompanied by an inhomogeneous deformation which was observed to be twinning in the low-temperature phase. 3'4 The transformations may occur by a "single interface" or by "multiple interfaces."5'6 In the "single interface" transformation, the twinned product phase consisted of two twin orientations as shown in Fig. 1. In the multiple interface transformation the product phase contained "domains" each of which contained two twin orientations, Fig. 2. Deformation of specimens containing transformation twins was achieved by motion of the twin boundaries. Releasing the applied stress resulted in the displaced twin boundaries returning towards their initial positions. This "pseudo-elastic" behavior of the boundaries varied with time after the formation of the twin boundaries by the transformation.

Jan 1, 1961

By AIME AIME

ON JULY 12, 1921, S. S. Arentz, representative at large from Nevada, introduced in the House of Representatives, under the number H. R. 7736, a bill to revise, amend and codify laws of the United States relating to the location of mining claims on public domain, and other purposes. This bill had been drafted by a committee of consulting engineers of the U. S. Bureau of Mines. The immediate purpose of this introduction in Congress was to make it avail- able for general information and discussion. In pursuance of this purpose Mr. Arentz issued the following circular: This proposed codification and revision of the mining laws of the United States as received from a committee of mining and metallurgical engineers appointed by the Director of the United States Bureau of Mines was introduced in the House of Representatives by the undersigned (who has operated and developed mines throughout the West for many years). It is submitted to prospectors, mine operators and mining engineers, all of whom are affected and vitally interested in the subject with the hope that they will give this bill their careful consideration and study.

Jan 1, 1921

By W. E. D. Stokes

WHEN history is written, the year of the blitzkrieg will go down as giving aviation its greatest impetus. No perceptible drop in military business, even with cessation of hostilities abroad, seems likely. The combined air force of the U. S. Army and Navy on July 1 was approximately 5000 planes, as against 50,000 planes currently discussed as necessary. Observers at the fronts are giving designers and metallurgists back home some realistic ideas to shoot at. As conventional runways reveal the location of airports to enemy raiders, operating bases are now masked. Difficult, often muddy and rough landing strips, requiring strong landing gears and exacting take-off and maintenance characteristics, are the specifications of war. This is "old stuff" to numerous mining operators in mountainous jungle areas where gradients up to 8 per cent are in more or less common use in such mountain landing fields. Although airplane building is not readily adaptable to assembly-line methods, a trend towards mass productions is now in evidence. Incidentally, a U.S. Army "Curtiss P-40" requires about 10,000 man hours of work to complete and is tied together with 75,000 rivets. During the past year a number of aircraft factories adopted the "shot-

Jan 1, 1941