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By James A. Lewis

It is the purpose of this paper to show the importance of sand characteristics, when combined with other physical data, in evaluating production obtained by secondary recovery operations, and to indicate the benefits to be gained from the application of these principles to primary production.

Jan 1, 1942

By Michael A. Toole, O&apos

INTRODUCTION The tremendous capital investment required to produce a low grade ore deposit demands a reliable answer to the question: "How much does it cost to drill a well to produce the uranium that geologists have indicated is there in the ground?" However, you will find the answers given will be many and varied, depending on whether they come from the operating company, the drilling contractor, a geologist, a reservoir engineer, purchasing agent, or whoever. Each generally considers only a limited area of the total operation. The operating company usually depends upon the drilling contractors, service companies, and consultants to supply expertise. Because it is often difficult to see the "whole picture" or even to agree upon what the "whole picture" is, planning a well program and its costs is often done piecemeal. Frequently, costs "saved" in one area of the program are needlessly spent in another, because the effect of one area upon the other was overlooked. Since the drilling fluid is such an influential part of the drilling program, it should be given utmost consideration when planning the overall program. As W. D. Lacabanne wrote in 1954: "The drilling fluid system is understandably called the heart of the rotary oil drilling rig. Any other type of rotary rig.... should benefit by the incorporation of mud fluids in the drilling scheme." And G. R. Gray mentions that "The driller recognizes the drilling fluid as one of the useful tools available to solve drilling problems." However, in minerals drilling, only in recent years has the drilling fluid been considered as more than a tool to get through special problem areas. Although there are many similarities between drilling for oil and gas and drilling for minerals, the differences in the drilling equipment used justifies designing specific fluids for the minerals drilling industry. NL Baroid/NL Industries, Inc. has been a leader in introducing such fluids and in providing technical know-how to the minerals drilling industry. The purpose of this paper is: (1) to discuss the selection of drilling fluids to meet specific drilling conditions during both exploration and production and (2) to show the interrelationship among factors present in the exploration and production phases that influence total well costs. DRILLING FLUIDS FOR DRILLING PROBLEMS The drilling fluid is a tool that can be used to improve drilling performance by improving hole cutting, cleaning, stability, and formation productivity. Properly formulated and maintained drilling fluids enable the drilling operation to be carried out with increased efficiency and lower total (overall) costs. However, it should be noted that not all drilling problems can be solved by even the most carefully prepared and maintained drilling fluids. Of the many possible drilling problems encountered in a well before reaching target depth, this paper will discuss only those most likely to be present in the shallow [61 to 610 m (200 to 2000 ft)] drilling operations in South Texas. LOST CIRCULATION Loss of circulation is the most common problem encountered in drilling. Because the losses occur under varied conditions, it is often difficult to determine the exact causes. "Lost circulation" or "lost returns" means the partial or complete loss of drilling fluid to voids in the formation. "Loss of water" while drilling with water may take place into any permeable section and should be distinguished from "water loss" or filtration of fluid through the filter cake of mud solids laid down on a permeable formation. "Loss of water" can frequently be stopped by the addition of colloidal sized clay particles such as high yield bentonites, whereas "water loss" may be controlled with organic polymers. Subsurface conditions that lead to loss of circulation can be classified as: (1) natural fractures, (2) induced fractures, (3) unconsolidated or highly permeable formations (loose gravel), and (4) cavernous formations (crevices and channels). Loss of circulation may occur whenever the borehole pressure exceeds the formation pressure. The greater the differential pressure, the more likely it is that circulation may be lost. To stop loss of whole mud, voids must be bridged so that a filter cake can be laid down on the permeable section. The plugging material must be of the proper size and shape to offer greater resistance to the fluid flow around it than the flow up the annulus. A plugging composition that satisfies these requirements may not be able to be handled by the small rig pump available.

Jan 1, 1979

By D. W. Frommer

Processing nonmagnetic taconites by selective flocculation-desliming and flotation requires large volumes of water. If impounded without treatment the effluents from these processes require excessively large areas for containment. Experiments conducted in the Bureau of Mines 900-lb-per hr pilot plant at the Twin Cities Metallurgy Research Center indicates that approximately 85% of the water needed to process Michigan nonmagnetic taconite could be reclaimed from the process itself. Water was reclaimed by the controlled addition of lime, sodium carbonate, and synthetic flocculant. As a result, turbidities were reduced to ?1000 ppm equivalent SiO2, while a Ca ion content of ?16 ppm was maintained in the finished effluent. Good-quality flotation concentrates were obtained with reclaimed water and, by means of some indirect comparisons, it can be concluded that the reuse of the water permits a savings of almost 2.0 lb per ton of NaOH, and probably as much as 0.25 lb per ton of fatty acid for total savings of 7.8-10.3 cents per ton of feed. These savings are nearly offset by an estimated chemical cost of 9.3[c] per ton for water treatment.

Jan 1, 1970

By G. Y. Chin, M. T. Dolan, W. L. Mammel

In the case of plastic deformation by slip, von Mises&apos; showed that an arbitrary shape change of a crystal generally requires the activation of five independent slip systems. The selection of the five active systems was worked out by Taylor ,&apos; who hypothesized that, among all combinations of equivalent slip systems which are capable of accommodating a given imposed strain, the active combination is that one for which the sum of the absolute values of the glide shears is a minimum. Taylor analyzed the case of {lll}( 110) slip for fcc metals and applied the analysis to crystals undergoing axisymmetric flow, which approximates the shape change of an embedded grain in a polycrystalline aggregate deformed in tension (or compression). For the twelve equivalent (111) (110) slip systems, there are 384 independent combinations of five slip systems that satisfy the imposed strain.&apos; Taylor laboriously calculated the value of M = ZjIyj /E for each combination (although some were missed) and obtained the minimum M, hence the active combination, for a number of axial orientations distributed throughout the stereographic triangle. (yj is shear from slip on the th system and e is the tensile strain). Detailed contours of constant minimum M were recently obtained by Hosford and Backofen using a simplified but equivalent Bishop and ill&apos; analysis. Due to the numerous combinations of slip systems involved in the calculations, however, the full potential of the powerful Taylor analysis has not been exploited. For this reason, we have recently utilized techniques of linear programming to obtain solutions of the Taylor analysis for axisymmetric flow, for slip on {110)(< 111), {112)(111), and {123)(111) systems as well as mixed slip composed of these three systems. These slip modes are of obvious importance in the deformation of bcc crystals. Some of the salient results are summarized below. 1) Stress-Strain Data for Polycrystal. The value of M averaged over all axial orientations is the ratio of the tensile flow strength of a randomly oriented aggregate to the critical resolved shear stress for slip. This value enters importantly in theoretical deductions of the polycrystalline stress-strain curve from single-crystal data.2&apos;3&apos;5 Table I lists the values of Ma,, for the several cases of slip, as obtained by the present computer work. 2) Texture Hardening. Since the value of M depends on the axial orientation, the (tensile) flow strength of a specimen may be increased through texture control.&apos; An example of the computer results is shown in Fig. 1, where contours of minimum M have been computer-plotted for the case of mixed slip on {110}(111), {112)(111),and {123}(11 1) systems. It may be seen that, under axisymmetric flow, wires of (111) and (110) axial orientations are 50 pct stronger than those oriented at (100) .

Jan 1, 1968

By Wm. Hamilton Merritt

With the exception of the Vancouver Island coal, all the western coal-fields owe their present development to the completion, in the autumn of 1886, of the Canadian Pacific railroad. While it could not be expected that a very great deal could be accomplished in three years, enough has been done to pretty thoroughly establish the coal-bearing areas and their correspondence with those which have been developed to the south of the boundary along the lines of the transatlantic railroads in the United States. This summer I visited some of the important developments in the coal areas of Washington Territory, largely with the object of being better able to appreciate the corresponding coal-bearing areas in British Columbia to the north. In Western Canada, coal-bearing rocks have been found in three zones: 1. In the plains to the east of the Rocky Mountains and in the eastern flanking ranges, the coal occurs in the Cretaceous formation (including the Laramie). 2. In the interior plateau of British Columbia, the coal is found in the Tertiary formation. 3. On the coast of British Columbia, Cretaceous and Tertiary rocks are found carrying coal, and on the Island of Vancouver the well known Nanaimo coal has been worked for years in the first named formation. In all of these zones, the coals vary from lignites up to higher grades, the factor determining quality being the amount of pressute to which they have been subjected. The intensity of this pressure is generally shown by the disturbance which the coals exhibit, and, in many cases, is almost directly in proportion to the distance of the deposits from mountain ranges. This seems to be also the opinion expressed by Mr. Bailey Willis in connection with his Census Report on the coals of Washington. It has been elsewhere stated

Jan 1, 1890

By C. L. T. Edwards

IN the preparation of this paper, the author has drawn upon experience with the operation of a blast furnace on 100 per cent scrap burden, which he believes was the first operation of its kind in the country. It is the writer&apos;s further belief that much of the controversy attending discussions of this subject may be obviated by the presentation of a group of facts that should be known by blast-furnace men and open-hearth men alike. The following question has been raised: "Is iron made with scrap in the blast-furnace charge as good iron as that made without scrap-made with straight ore?" This question may be answered in part by the fact that the open-hearth men of the Bethlehem Steel Co. who used pig iron from a blast furnace that operated on 100 per cent steel scrap found no difficulty in the processing of such iron other than that to be expected from the known analysis. OPERATION WITH 100 PER CENT STEEL SCRAP During World War I, there was accumulated at the Bethlehem plant of the Bethlehem Steel Co. some 22,000 tons of alloy-steel turnings and borings. This scrap material was highly corroded and, like alloy-steel turnings of that period, were as a drug on the market. There was also a small tonnage of scale, rich in valuable metal. If this scrap could be worked up into pig iron, it would become readily available for use in the open hearth. In order that the pig iron should contain the maximum percentage of nickel, permission was obtained from the Management to try a 100 per cent scrap operation. Accordingly, a blast furnace was swung over on July 25, 1919; the percentage of steel scrap increased more or less irregularly until July 29, when l00 per cent steel turnings were charged. Except for occasional charges of nickel scale as an "extra," the operation continued uninterruptedly until Aug. 27, when the furnace was swung back to the regular ore-ore and scrap-operation. During this period, the furnace production ranged from a low of 568.60 tons to a maximum of 766.07 tons. At the swing-over from i00 per cent scrap to the regular burden, the charge hung up rather severely. While the latter condition has nothing to do with the object of the paper, a brief discussion of the experience will appear later because of the interest it may have for blast-furnace operators. In Table I, results of the first and last days of the ore charge are shown, July 25 and July 29. The last column shows a summary for the period of maximum scrap charge. The furnace employed had a hearth 16 ft. 0 in., bosh 22 ft. 0 in., stock line 15 ft. 6 in., bell 11 ft. 6 in., batter ¾ in., bosh angle 73° 27&apos; and a Baker-Neuman top, with gas-engine blowers. Analyses Range of Material Charged Gravel: Si02, 64.40 to .7o.54 per cent; A1203,3-52 to 4.58; CaO, 7.27 to 9.49; M90, 5.09 to 6.14; FeO, 1.67 to 3.34, ignition loss, 9.50 to 13.83.

Jan 1, 1941

Department of Conservation and Development, State of North Carolina, Raleigh, N C H J Bryson, State Geologist. The latest list of publications will be sent upon request. Of the many Bulletins, Economic Papers, Circulars and Volumes issued by the Department of Conservation and Development, the following are available and relate to mining and geology of the state ? Bulletin 18, Bibliography of North Carolina geology, mineralogy and geography (1909), 50 cents, 21, The Gold Hill mining district (1910), 15 cents, 22, Report on Cid mining district (1911), 15 cents, cloth 75 cents, 25, Zircon, monazite and other minerals, 15 cents, cloth, 75 cents, 28, Limestones and marls, 15 cents, 29, Kaolins of North Carolina, 50 cents, 31, Deposits of brown iron ore, 50 cents, 32, Magnetic iron ores, 15 cents, 33, The Deep River coal field, 50 cents, 37, Pyrophyllite deposits, 35 cents A series of the Economic Papers review the mining industry in North Carolina for the years cited Those now available are Economic Paper 23 (1908-1909-1910), 10 cents, cloth, 50 cents, 49 (1913-1917), 20 cents, 55 (1918-1923), 25 cents, 60 (1924¬1925), 15 cents, 63 (1927-1928), 25 cents. Other available Economic Papers on geology and mining are No 3, Talc and pyrophyllite deposits (1900), 25 cents; 58, Oil prospecting well near Havelock (1927), 5 cents, 59, Oil-bearing shales of Deep River Valley (1927), 10 cents Available volumes on geology. Vol 1, Corundum and the basic magnesian rocks (1905), 35 cents, cloth, $150, 5, The Cretaceous formations of North Carolina (1923), cloth $1 75

Jan 1, 1933

Jan 1, 1900

By Charles P. Williams

DURING the fall of the year 1873, attention was redirected to the occurrence of lead ores in Southwestern Arkansas (chiefly in Sevier County), and somewhat extensive explorations of the deposits have since been made in the hope of finding the ores sufficiently argentiferous to be profitably worked. How far the expectations have been realized I am not authentically advised, but samples of the galena ore, yielding 62.09 per cent. of lead, gave on assay at the rate of 15 3-10 ounces of silver to the ton of ore. This was the highest result obtained by myself, though I am informed that higher yields have been obtained by others. Among the samples of ores from this locality, forwarded to me in January last, was one specimen which I at once recognized as stibnite, and, on notification, other specimens of the same from Sevier County were forwarded me. The first specimen of the several received contained 11.51 per cent. of gangue, 57.62 per cent. antimony, 4.57 of bismuth, with small amounts of arsenic and iron. The latest result from a portion of another hand specimen I append in full, with duplicate estimations of the arsenic, bismuth, and gangue. The analyses were all conducted by Mr. C. R. Winters, under my direction, and in the case of those given below the ore was separated as closely as possible from the gangue before analysis. The results are for the mineral freed from hygroscopic moisture, and are as follows:

Jan 1, 1875

By J. Parke Channing

THESE days of great industrial and social problems in America produce many suggested solutions and great changes. The practical engineer and employer of labor views these problems differently from the labor leader or the social reformer, but as never before he is sincerely interested in solving them in a way that will be just to all. The inevitable tendency of the day is toward "industrial betterment," "safety," "industrial education," "efficiency," and the many other things&apos; which have become so familiar to progressive employers. There is no longer any question that these things are worth while from both the hu¬man and economic standpoints. They "pay" in dollars and cents. The very center of final success in improving conditions and increasing the efficiency of workingmen must be the spirit of fairness and a knowledge on the part of the employer of how to deal sympathetically and intelligently with his employees. Every progressive employer knows how greatly he desires foremen, superintendents, managers and others who possess these qualities. On the other hand, we are all familiar with serious mistakes made by young graduates of engineering schools who have had no opportunity to develop these qualities, and who have no real appreciation of the worth of the workers. Indeed, one wonders whether much ill-feeling, labor difficulties, and many strikes could not be avoided if such men had the right attitude. Is there any way of remedying this condition? If this particular difficulty can be solved, if these young engineers, many of whom are our coming leaders of industry, can be given the right perspective and the right understanding of these other problems in addition to fair, sympathetic methods of handling men, many of our other problems will be solved-not at once, but gradually and permanently, as these men make good and become influential in paths of industrial righteousness and industrial peace. Many progressive employers of to-day have enlarged their own perspective and realize the great importance of enlarging the perspective of those who shall follow them.

Jan 3, 1915

By James J. Halbouty

The restraining effects of war conditions on oil-field development are well illustrated by statistics on South Texas † fields for the year 1942. Statistics also show a decline in wildcatting, but this decrease is much smaller than that shown by field activity. In comparison with results in 1941, there was a reduction of about 44 per cent in the total number of wells drilled in the area (802 in 1942 against 1452 in 1941) This 44 per cent drop represents declines of 50.4 per cent in field wells and of 17.4 per cent in rank wildcats. Field wells (exclusive of 18 wildcats that discovered fields) totaled 598; also, 204 rank wildcats were drilled (see Tables 3 and 4). The corresponding figures for 1941 are 1205 field and extension wells and 247 rank wildcats. In this connection, it should be noted that whereas in 1941 the rank wildcats made up only 17 per cent of all wells drilled in the area, their percentage of the 1942 total was 25.4 per cent. In spite of the decrease of 43 in the number of rank wildcatst drilled, there were 18 new productive areas discavered, one more than the 17 new fields found in 1941. Thus the field-discovery rate for 1942, one new field for every 11.3 wildcats drilled, compares favorably with the I to 14.5 rate of 1941. Thirteen new producing levels were opened in fields; this includes the finding of 44&apos; gravity crude on the west flank of the Sejita field in a 5700-ft. sand, which produccs distillate higher on the structure. Interesting, and showing the general scarcity of sand discoveries, is the fact that of the 13 new sands discovered, 7 were found in Jim Wells County. The year&apos;s sand-discovery rate of one new level for every 46 field wells compares very unfavorably with the I to 19.7 rate of 1941, during which 61 new producing horizons were found. Developmeilt of new fields was on a small scale. In several instances activity in these areas was not carried beyond the drilling of the discovery well. The field discoveries of 1942, together with the type of production obtained from the discovery wells and the total number of wells (productive and dry) drilled in them, are given below: Discovery Num- Field.I County Well her Produced Wells I. Cadena....... Duval Oil 2 a. Garza......... Duval Oil I 3. Dinn......... Duval Gas I 4. Keller......... Duval Gas I 5. East.......... Tim 0 11 I 6. Green Branch . McMullen Gas 3 7. Frost. .GreenBranch........ Starr Oil I 8. Garcia........ Starr Oil 6 9. Ulrich........ Starr Oil 4 10. Lykes......... Webb Oil 2 11. McLean....... Webb Oil 9 Iz. Alamo........ Hidalgo Distillate 2 and gas 13. Penitas....... Hidalgo Distillate 2 and gas 14. Xmpnan..... Jim wells i a 15. South Premont Jim Wells Distillate i and gas 16. Quinto Creek.. Jim Wells Gas 4 17. Roth.. . :..... Jim Wells Gas I I 18. South Sinton.. San Distillate I Patricio and gas . • See Table 2 for data on discovery wells and Table I for information on these fields. • See Table 4.

Jan 1, 1943

By James J. Halbouty

The restraining effects of war conditions on oil-field development are well illustrated by statistics on South Texas † fields for the year 1942. Statistics also show a decline in wildcatting, but this decrease is much smaller than that shown by field activity. In comparison with results in 1941, there was a reduction of about 44 per cent in the total number of wells drilled in the area (802 in 1942 against 1452 in 1941) This 44 per cent drop represents declines of 50.4 per cent in field wells and of 17.4 per cent in rank wildcats. Field wells (exclusive of 18 wildcats that discovered fields) totaled 598; also, 204 rank wildcats were drilled (see Tables 3 and 4). The corresponding figures for 1941 are 1205 field and extension wells and 247 rank wildcats. In this connection, it should be noted that whereas in 1941 the rank wildcats made up only 17 per cent of all wells drilled in the area, their percentage of the 1942 total was 25.4 per cent. In spite of the decrease of 43 in the number of rank wildcatst drilled, there were 18 new productive areas discavered, one more than the 17 new fields found in 1941. Thus the field-discovery rate for 1942, one new field for every 11.3 wildcats drilled, compares favorably with the I to 14.5 rate of 1941. Thirteen new producing levels were opened in fields; this includes the finding of 44&apos; gravity crude on the west flank of the Sejita field in a 5700-ft. sand, which produccs distillate higher on the structure. Interesting, and showing the general scarcity of sand discoveries, is the fact that of the 13 new sands discovered, 7 were found in Jim Wells County. The year&apos;s sand-discovery rate of one new level for every 46 field wells compares very unfavorably with the I to 19.7 rate of 1941, during which 61 new producing horizons were found. Developmeilt of new fields was on a small scale. In several instances activity in these areas was not carried beyond the drilling of the discovery well. The field discoveries of 1942, together with the type of production obtained from the discovery wells and the total number of wells (productive and dry) drilled in them, are given below: Discovery Num- Field.I County Well her Produced Wells I. Cadena....... Duval Oil 2 a. Garza......... Duval Oil I 3. Dinn......... Duval Gas I 4. Keller......... Duval Gas I 5. East.......... Tim 0 11 I 6. Green Branch . McMullen Gas 3 7. Frost. .GreenBranch........ Starr Oil I 8. Garcia........ Starr Oil 6 9. Ulrich........ Starr Oil 4 10. Lykes......... Webb Oil 2 11. McLean....... Webb Oil 9 Iz. Alamo........ Hidalgo Distillate 2 and gas 13. Penitas....... Hidalgo Distillate 2 and gas 14. Xmpnan..... Jim wells i a 15. South Premont Jim Wells Distillate i and gas 16. Quinto Creek.. Jim Wells Gas 4 17. Roth.. . :..... Jim Wells Gas I I 18. South Sinton.. San Distillate I Patricio and gas . • See Table 2 for data on discovery wells and Table I for information on these fields. • See Table 4.

Jan 1, 1943

By J. B. Fisken

(Butte Meeting, August, 1913.) BEFORE touching upon the immediate subject of this paper a few facts of a historical nature as to the general application of electricity to mining might be of interest. As to what was actually the first application of electricity to mining, opinions will no doubt always differ. My experience does not go back far enough, nor are the records to which I have had access of any value as covering this point. Sydney F. Walker, a man whose pioneer experience in the application of electricity to mining purposes dates back as far as 1876, ,gave an interesting resume of the subject in an address before the South Wales branch of the Association of Mining Electrical Engineers at its 1.913 session, and, unless his statements are shown to be wrong, they should be accepted as facts. According to Mr. Walker, the ignition of charges of blasting powder was the first operation in mining to be accomplished with the aid of electricity. Very frequently this energy was furnished by a static machine and occasionally by a magneto generator. Later, this was followed by the application of electricity to bell signals, and we are told that this application was looked upon skeptically and regarded as an expensive experiment by the mining managers of those early days. At the Paris Exposition of 1878, there was exhibited an electric lamp, which suggested future possibilities to the mining engineers of those days. The first successful application of electric lighting to underground excavations that I have been able to find any record of is that of M. Blavier. In the year 1879&apos; he installed two Serrin lamps and successfully illuminated one of the large underground chambers in the Angers slate quarries. Another early application of electricity to the lighting of mines is that in the large chambers in the salt mines of Maros-Ujvár, in Hungary; these have been regularly and successfully lighted elec-

Jan 6, 1913

By Thomas W. Healy

Particles present in mineral processing systems that are termed ultrafine are those that are small enough to be unaffected by gravity or the flow conditions imposed on the pulp. As such, their interaction with one another and with other larger particles are controlled by specific attractive and repulsive colloidal or surface interactions. Electrostatic repulsion between ultrafines is dominated by surface potential, double layer thickness and specific adsorption potential effects - controlled by pH, salt and complexing ion concentrations. Attraction due to van der Waals interactions must be assessed in terms of bulk and surface coating effects and of particle size and shape. The net effect of attraction and repulsion must finally be related to the average kinetic energy of particles in the real system.

Jan 1, 1979

EXECUTIVE COMMITTEE OF THE BOARD OF DIRECTORS CHESTER A. FULTON, Chairman CARROLL A. GARNER H. Y. WALKER WALLACE E. PRATT FELIX E: WORMSER PAUL D. MERICA, Consultant FINANCE COMMITTEE OF THE BOARD OF DIRECTORS ERIE V. DAVELER, Chairman WILBER JUDSON RUSSELL B. PAUL HENRY KRUMB, Consultant

Jan 1, 1944

Jan 1, 1935

By Charles P. Williams

BY PROFESSOR CHARLES P. WILLIAMS, ROLLA, MISSOURI. During the fall of the year 1873, attention was redirected to the occurrence of lead ores in Southwestern Arkansas (chiefly in Sevier County), and somewhat extensive explorations of the deposits have since been made in the hope of finding the ores sufficiently argentiferous to be profitably worked. How far the expectations have been realized I am not authentically advised, but samples of the galena ore, yielding 62.09 per cent. of lead, gave on assay at the rate of 15 3-10 ounces of silver to the ton of ore. This was the highest result obtained by myself, though I am informed that higher yields have been obtained by others. Among the samples of ores from this locality, forwarded to me in January last, was one specimen which I at once recognized as stibnite, and, on notification, other specimens of the same from Sevier County were forwarded me. The first specimen of the several received contained 11.51 per cent. of gangue, 57.62 per cent. antimony, 4.57 of bismuth, with small amounts of arsenic and iron. The latest result from a portion of another hand specimen I append in full, with duplicate estimations of the arsenic, bismuth, and gangue. The analyses were all conducted by Mr. C. R. Winters, under my direction, and in the case of those given below the ore mas separated as closely as possible from the gangue before analysis. The results are for the mineral freed from hygroscopic moisture, and are as follows: I. 11. Mean. Sulphur,.. 28.618 .. . 28.518 Antimony,.68.576 .. . 68.676 Arsenic,..6 47 .474 .497 Bismuth,..521 .498 .509 Iron,.......762 .. ..762 Gangue,..944 .948 .946 99.868 99.808 This result indicates that the ore is stibnite.

By NORMAN D. FitzGkrald

IN 1942 the outstanding characteristic of the petroleum industry was the multiplicity of war-induced distortions in virtually every segment of the business. So devastating was the success of the Nazi submarine campaign along the shores of the western Atlantic and on transoceanic routes that within six months after our entry into the war petroleum rationing was necessary in the East Coast area. The conquest of the Netherlands Indies by the Japanese three months after the opening of the war in the Pacific cut off our normal sources of rubber, and in our first year of war nationwide rationing of gasoline had to be invoked to conserve rubber-borne transportation facilities. Meanwhile the oil industry faced the imperative necessity for rapid expansion in the output of aviation gasoline and later accepted the vast responsibility for developing a new industry. synthetic rubber manufacture. Probably no other essentially peacetime industry has been forced to make so many complicated adjustments, yet its response to its wartime obligations has been nothing short of dramatic.

Jan 1, 1943

R. G. BROWN, Bodie, Cal.: Mr. Rickard&apos;s paper, with its valuable illustrations, brings into fresh clearness the game of hide-and-seek which the miner must play with his ore-deposit; but, more than this, it goes far towards classifying those perplexing idiosyncrasies which, while unclassified, constitute a labyrinth almost without clue. Probably every engineer can add to the list by the mention of at least one fresh detail from his own experience, and I for one would like to comment on two of Mr. Rickard&apos;s divisions. To what he has written about " walls within walls" and " walls without walls," the accompanying Figs. 1 and 2 may be appropriate, the more so as they represent conditions obtaining in a part of the Butte copper-belt more typical of the copper-veins as a whole than the Gagnon, which, in some respects the most interesting mine in the camp, stands almost alone in many particulars. (See nuns., xvi., 62.) Fig. 1 was sketched in January, 1895, in the stopes above the 700-foot level of the Colusa-Parrot mine, east of the Parrot and southwest. of the Anaconda. The stope, the commercial foot-wall of which is shown at A, was 30 feet wide at this section, the pay-ore being massive chalcocite, jumbled with bornite, pyrite, quartz and thoroughly broken-down granite. A and At are inch-thick seams of black talc; B, B&apos; and B" are also talc, possibly 1/8-inch thick. In the plane of the section the "banded quartz " and " quartz and pyrite " were both of too low grade for extraction, but 5 feet back along the stope had been of fair value. The granite with quartz and bornite between Bt and A&apos; was pay-ore, but that to the right of B" was not. In both cases the ferro-magnesian minerals had been removed, leaving, where not obscured by ore, faint, dark patches. Between A&apos;

Jan 1, 1897

By Frederick T. Williams

The purpose of this paper is to discuss the relative merits of the large 31/8-in. machine and the small 2 1/4-in. tappet machine in driving development-headings; and although the data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winzing. Recently we drove two parallel cross-cuts through the same formation, using a 3 1/8-in. machine at the breast of one crosscut, and a 2 1/4-in. machine of the same make at the breast of the other. The results of this work afforded an ideal comparison, since in both cases the headings were advanced through rock practically of the same hardness and breaking-properties, the amount of sludging was equal, and there was no difference in the condition of the steel or the machines, the air-pressure or the experience of the operating crews. Some operators in the Cripple Creek district contend that there is ground which cannot be handled with the small machine, the holes being too small to contain enough powder to "pull " the ground, etc. The results obtained in working the property of the Portland Gold Mining Co., however, show that the ground worked by them does not fall in this class. During a period of two years there have been driven, with the small machine, 4 miles and 308 ft. of development-headings, through a diversity of ground, including Pike&apos;s Peak granite (a coarsely porphyritic type of granite), highly indurated andesitic or pho-nolytic breccia, true massive andesite, trachytic phonolyte, tuffs, and along dikes of decomposed basalt and hard phonolyte. In every instance a satisfactory record was made. The headings here describe? mere driven through highly indurated andesitic breccia, having a hardness of from 5.2 to 7.2 and a sp. gr. of from 2.2 to 2.8. The action of the breccia under the drill was not materially different from that of ordi-

Jan 1, 1907