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By Victor V. Damiano

THOMPSON1 proposed a very convenient nomenclature in which an imaginary regular tetrahedron was used to facilitate the analysis of dislocation interactions in fcc materials. The faces of the tetrahedron were constructed parallel to four different sets of (111) planes, and the six edges of the tetrahedron then represented the six 1/2 [110] Burgers vectors. The lines which joined the midpoint of a tetrahedron face with the ends of one of its edges represented the Burgers vectors of the partial dislocations into which the six 1/2 [I101 Burgers vectors dissociate. Using Frank&apos;s2 notation, all of the dislocations and their partial dislocations were identified and numerous possible interactions were postulated. The case of hexagonal crystals is unfortunately more complex, but it appears convenient to introduce a system similar to that of Thompson1 to describe the various slip planes and Burgers vectors encountered in cph structures. The system proposed has limited application but serves to identify the following slip systems {0001} <l20>, {1010} <1120>,

Jan 1, 1963

By G. A. Koenig, Moritz Stockder

Locality and Geological Occurrence.—The Atpine region of Southwest. Colorado. cort~prieiog the San Juan and Uncon~paghre Mountains, is con~posed of a deeply eroded sheet of acid eruptive rocks, overlying in part gneissic schiets, and in part limestones and sandstones, including portions of the Silurian, Devonian, arid Carboniferous systems. The section is clearly and beautifully exposed along the Uncompghre River from its headwaters to its exit from the mountains. The river&apos;s course from the town of Ouray towards the Los Pinos agency is due north, and four miles from Ouray, in this directiou, the Uocampaglire receives from the east the Red Casm Creek. Following up the narrow canon we find the section through white. sandotone in strata dipping to the north and west, and belonging either to the lower or middle Devonian system. Presently the steep cafion-like character of the ravine gives place to more gentle slopes, ad we have entered crysralline rock—porphyry. The contact is well marked, for the sandsbne, to a depth of from six to ten feet, resembles quartzite, i. e., is serui&apos;fusd. Ascending still higher, a small

Jan 1, 1881

By M. R. J. Wyllie

In a recent publication1 wetting phase relative permeability was exvressed as: and it was stated that a similar expression applied, mutatis mutandis, to non-wetting phase relative permeability; i.e., In Equations (1) and (2), Sw and S0 are respectively the wetting and non-wetting phase saturations as a fraction of the pore volume; PC is the capillary pressure; I; the wetting phase electrical resistivity index; IN, the analogous non-wetting

Jan 1, 1951

By M. R. J. Wyllie

In a recent publication1 wetting phase relative permeability was exvressed as: and it was stated that a similar expression applied, mutatis mutandis, to non-wetting phase relative permeability; i.e., In Equations (1) and (2), Sw and S0 are respectively the wetting and non-wetting phase saturations as a fraction of the pore volume; PC is the capillary pressure; I; the wetting phase electrical resistivity index; IN, the analogous non-wetting

Jan 1, 1951

By Olin G. Bell

The year 1934 in Southwest Texas was marked by aggressive development and exploratory work and resulted in the finding of five new fields and a new producing horizon in one of the older fields. This activity is the result of a reasonable market outlet for production, on both oil and gas, and the fact that drilling and operating costs are reasonable and that possibilities of finding new productive areas are rather high. A large part of the area is prospective and very little, if any, satisfactory surface geological work can be done. This, together with the possibility of finding new productive areas, stimulates wildcatting throughout the counties under discussion. Development work continued actively in all of the newer fields. Exploratory work was most intense in Duval, McMullen, Starr and Zapata counties. The activity in Duval and McMullen counties was the result of persistent efforts to find new trends of production similar to and perhaps associated with the Government Wells group of fields. The activity in Starr and Zapata counties was stimulated by the discovery of the Sam Fordyce field in Hidalgo County as well as the continued effort to find new productive trends southeastward from some of the older fields in northeastern Zapata County and western Jim Hogg Comity. Statistics on production are shown in Tables 1 and 2. New Fields Lopeno.—The Lopeno gas field in the southwestern part of Zapata County was opened in August, 1934, by R. B. Morrison No. 1 Ramirez. This is an anticlinal structure mapable in Claiborne beds and the producing horizon is the Queen City sand at 2100 ft. in the Upper Mt. Selman. At the close of the year only two gas wells had been completed but drilling operations were in progress on several other wells and a gas line was being laid to the field so that withdrawals from the area will begin early in 1935. Comilas.—The Comitas field was opened by Merle Gunby No. 1 Haynes in a sand at 800 ft. in an area southwest of the Escobas field. The discovery well had an initial production of only about 16 bbl. of oil

Jan 1, 1935

By Lewis W. MacNaughton, F. L. Burchard

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Coolie, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay Counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. DevELopments during 1941 Nearly 1600 wells were drilled in the district during 1941 as compared with more than 1700 in 1940. However, the ratio of successful drilling operations was higher and some 1200 oil wells were completed. Production held about even with the previous year, as did the number of producing oil wells. Known oil reserves increased slightly throughout exploration, which generally was carried on at greater depths than in former years. The average depth of discovery wells was 300 ft. deeper than in 1940. Although discoveries were evenly divided numerically between horizons above the base of the Strawn series and those below the Strawn, the deeper horizons, including the Bend series of the Pennsylvanian, the Mississippian limestone, and the Simpson and Ellenburger of the Ordovician, furnished most of the increase in oil reserves. The largest single addition to the reserves was in the Ellenburger formation in the K.M.A. field. During the year 112 wells were completed in this horizon, bringing the total developed acreage to some 4600 acres. The Straan series in K.M.A. also received considerable development in 1941, with 114 completions. K.M.A. Pressure Maintenance Satisfactory progress was made by the K.M.A. Pressure Maintenance Association in 1941. At the end of the year, 99 wells were being used for input and total monthly volume of gas returned to the reservoir reached a high of 340,548 M cu. ft. in December from a low of 208,853 M cu. ft. in February. Total volume of gas returned during 1941 was 3,306,052 M cu. ft. To the end of the year, 150 cu. ft. of gas had been returned for every barrel of oil produced from the reservoir while the input ratio for December was 397 cu. ft. Per

Jan 1, 1942

By F. L. Burchard, Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Coolie, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature are in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay Counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. DevELopments during 1941 Nearly 1600 wells were drilled in the district during 1941 as compared with more than 1700 in 1940. However, the ratio of successful drilling operations was higher and some 1200 oil wells were completed. Production held about even with the previous year, as did the number of producing oil wells. Known oil reserves increased slightly throughout exploration, which generally was carried on at greater depths than in former years. The average depth of discovery wells was 300 ft. deeper than in 1940. Although discoveries were evenly divided numerically between horizons above the base of the Strawn series and those below the Strawn, the deeper horizons, including the Bend series of the Pennsylvanian, the Mississippian limestone, and the Simpson and Ellenburger of the Ordovician, furnished most of the increase in oil reserves. The largest single addition to the reserves was in the Ellenburger formation in the K.M.A. field. During the year 112 wells were completed in this horizon, bringing the total developed acreage to some 4600 acres. The Straan series in K.M.A. also received considerable development in 1941, with 114 completions. K.M.A. Pressure Maintenance Satisfactory progress was made by the K.M.A. Pressure Maintenance Association in 1941. At the end of the year, 99 wells were being used for input and total monthly volume of gas returned to the reservoir reached a high of 340,548 M cu. ft. in December from a low of 208,853 M cu. ft. in February. Total volume of gas returned during 1941 was 3,306,052 M cu. ft. To the end of the year, 150 cu. ft. of gas had been returned for every barrel of oil produced from the reservoir while the input ratio for December was 397 cu. ft. Per

Jan 1, 1942

AN extremely successful meeting, under the joint auspices of the Ohio Section and the Iron and Steel Committee, was held at Cleveland on April 19 and 20, about one-half of those in attendance being from the Cleveland district and the other half from a distance. The morning session on April 19, C. K. Leith presiding, was opened by the presentation of the ad-dress of which an excerpt is printed on the opposite page. In the subsequent discussion R. A. Allen pointed out that the meeting had not been called "to blow the lid off the tariff" since that is only one of the many problems connected with the wisest utilization of man-ganese, and it was the purpose of this meeting to con-sider all those interdependent problems. The purpose of the tariff was to develop an adequate domestic sup-ply, and that result had not been accomplished. An-other important problem, linked with the tariff, is the need for assuring, while we are at peace, an adequate war supply of manganese, and at present this country has no such policy. D. F. Hewett said that his 3-months&apos; trip in Europe last summer had impressed him with the fact that England had once been in the position United States now is in, of being the principal world&apos;s producer of all the more important minerals and with a declining reserve had gone on a free-trade basis. No one pointed out that, with the exception of tin, the present relative position of England is due more to an increase in pro-duction in other countries, rather than to a decrease of domestic production. J. Sharshall Grasty referred to recent development work-in Virginia where of 30 per cent easily concen-trated manganese ore about 300,000 tons has been blocked out and possible and probable ore amounting to 700,000 tons more is indicated.

Jan 5, 1927

All the Technical PUBlications and Preprints published in 1932 are available at Institute headquarters. They are also on file in public, university and technical libraries and, when so indicated in the list, may be found in the Transactions. Copies of the Technical Publications have been mailed to those members of the Institute who are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti-tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Copies of Preprints may also be obtained from the Secretary&apos;s office. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. Nonmembers may purchase the papers at the prices mentioned. Metal Mining Technical Publi- Title Author Meeting Trans. cation Volume No. and Page* 484-A.45 Propeller Type Mine Fan at Moose A. S. Richardson New York 102, 88. 95 F.52 Shaft. Butte. Montana (13) Feb.. 1932 487-A.46 Progress in the Improvement of Max H. Barber New York. Methods and Equipment at Feb., 1932 Open-pit Iron Mines on the Lake Superior Iron Ranges (9) Pre. Sand Filling through Pipes and Lucien Eaton New York, 102, 33, 41 Boreholes (9) Feb., 1932 Milling And Concentration 445-B.37 Soap Flotation of the Nomulfides Will H. Coghill New York. H.19 (18) J. Bruce Clemmer Feb., 1932 461-B.38 Principles of Flotation—An Experi- I. W. Wark New York. mental Study of the Effect of A. B. Cox Feb.. 1932 Xanthates on Contact Angles at Mineral Surfaces (48) Iron and Steel Division 447-C.81 Electrochemical Potentials of Nitri- Shun-ichi Satoh New York, fied Steels (31) Feb.. 1932 450-C.82 Reaistanoe of Iron-aluminum Alloya N. 9. Ziegler New York. 100, 267. 670 E.143 to Oxidation at High Tempera- Feb., 1932 tures (8) 451-C.83 Pressure Welding of Low-carbon C. H. Austin New York. Steela with Theoretical Con- W. S. Jeffries Feb.. 1932 siderations on the Mechanism of Such Welding (42) 453-C.84 Inclusions—Tbeir Effect, Solubility C.E.Sims New York, 100, 154, 176 and Control in Cast Steel (24) 0. A. Lillieqvist Feb., 1932

Jan 1, 1932

By Michael Shaughnessy, O&apos

The outstanding features of the Coloinbian situation for the year 1929 were legal and political. The passage of Law 84 and the promulgation of the Regulatory Decree 150 were recounted in the review for 1928, as was also the Presidential proclamation suspending this law and its accompanying decree until decision could be reached in the suits filed against them before the Supreme Court and the Council of State. Early this year the Minister of Industries, Jose Antonio Montalvo, announced the appointment of a commission of foreign experts to aid in drafting a new petroleum law. He requested all of the foreign experts employed not to consult with the oil company representatives in Bogota, and these experts were therefore shut off from receiving any suggestions from those who had actually operated in the country and knew the conditions under which operations would take place. It was to be expected that the provisions of a law suggested under such circumstances would not meet operating conditions satisfactorily. The specific objections are stated in O&apos;Shaughnessy&apos;s South American Oil Reports (April, 1929). An especially qualified commentator observes that one of the curious provisions of the proposed law was the high royalty on gas—5c. per 1000 cu. ft. of gas produced. There was also a provision requiring 20 per cent. of the stock of the company operating in Colombia to be offered for sale to Colombians. The bill failed to pass Congress in the closing hours of the session. The Supreme Court, in the meantime, handed down its decision on Law 84 of the previous year and Regulation 150 covering the enforcement of that law. Contrary to expectation, the majority opinion of the Court practically affirmed the constitutionality of both the law and the regulatory decree, with the exception of Article 20 and parts of Article 21 of the decree which referred specifically to the registration of private properties. At the time the suit was filed against Law 84 and Decree 150 the operation of these measures was suspended by the Executive. Law 84 and its Regulatory Decree 150 still remain suspended as the Council of State has not yet brought in a decision upon the questions raised in the suits instituted by the various companies against the law and decree, and at the moment of this writing it appears unlikely that such a decision will be reached by that body.

Jan 1, 1930

By Gloyd Wiles

THE eastern section of the Park City dis-trict is drained to an elevation of 6300 ft. by means of the Ontario drain tunnel owned and maintained by Park Utah Consolidated Mines Co. This elevation represents a depth of 920 ft. in Park City Consolidated Mines Company&apos;s property. When development below the goo-ft. level was commenced, sinking was at-tempted through an incline winze in the fissure. The intensely fractured quartzite forming the walls of the vein could not be held after water was encountered, so it was decided that further sinking should be done in a vertical winze far enough in the foot-wall to be in the more solid quartzite out-side the fractured zone containing the vein. Progress was good until a depth of 200 ft. below water table was reached, where the flow of water became serious. Sinking pro-gressed 300 ft., to the 1200-ft. level, and there approximately 750 gal. of water per minute was being pumped. The last 20 ft, of sinking cost more than $200 per foot direct charges, whereas the over-all cost for the 300 ft. was $100 per foot. This high last cost was caused by excessive lost time in pumping. Crosscutting to the vein disclosed the fact that the 1050-ft. level had been devel-oped only after drainage had been effected from the 1200-ft. level, but that the 1200-ft. level could not be opened because of the

Jan 1, 1940

By Timothy Collins

There was once a speculative period of interest in small mining companies that is commonly referred to as "the uranium boom of the 50&apos;s." In the late 60&apos;s, there was a second mining stock boom: it centered around uranium and silver, when silver had reached a new high of $3.60. In the mid 1970Js, there may be a new boom in the making, and it appears that substantial public and institutional interest in mining equities will finally result in a viable long-term capital market rather than the boom-or-bust pattern of the 50&apos;s and 60&apos;s. The reason for Wall Street&apos;s renewed interest in mining is understandable: most mineral commodities have recently gone up in price. Domestically, these price increases have come in the wake of the inflationary spiral unleashed by years of unbridled government deficit spending and erratic fiscal and monetary policies. Internationally, of course, the biggest push for higher prices has come from third-world countries whose primary income derives from indigenous natural resources. Many of these countries-whose fiscal and monetary policies haven&apos;t been models of excellence either-have attempted to cope with the worldwide economic mess by forming cartels that could control the price of commodities. What&apos;s happened to petroleum is well-known; what&apos;s happened to copper, bauxite, phosphate, and uranium is part and parcel of the same syndrome.

Jan 9, 1975

By W. E. Coughlin, R. L. Faverty, F. H. Lightner

The intent of this paper is to present the general strategy and method of implementation to achieve a "fast-track" mine development. The major objectives of a "fast-track or rapid development schedule are to minimize front-end development expenditures and to realize an early cash flow from operations. The Borealis project of Houston International Minerals Corp. (HIMCO) is used as the working example to illustrate the development schedule. Borealis is a 2.9 kt/d (2,500 stpd) gold-silver heap leach operation near Hawthorne, NV.

Jan 1, 1984

Discussion of the paper of N. V. Hansell, presented at the Cleveland Meeting, October, 1912, and published in Bulletin No. 72, December, 1912, pp. 1497 to 1,517. C. Q. PAYNE, New York (communication to the Secretary*) :-Mr. Hansell has presented in his paper a very interesting and valuable summary of the various methods of enriching iron-ores which have been developed during recent years. Particularly striking in this connection is the high degree of enrichment of the concentrates from magnetic iron-ores which is now commercially feasible. Magnetic concentrates containing from 6 7 to 139 per cent. of metallic iron, showing an efficiency of 90 and even 95 per cent. in. their separation, are not now uncommon. Such results exceed those obtained by gravity methods of treatment of all copper-, lead-, and zinc-ores, and are only equaled in the cyaniding of gold-ores and in the flotation treatment of certain copper-ores. It is of interest to note that the-type of magnetic field which is employed in securing these results, in the Gröndal (wet) and the Ball & Norton (dry) systems of treatment is the same in each case : viz., a field of alternating north and south poles. The credit for developing this simple and useful field, which has found so wide an application both in this country and abroad, is due to two American inventors and engineers, Clinton M. Ball and Sheldon Norton. At the same time, it should be noted that part of the improvement in the grade of the magnetic concentrates, especially in the case of the wet treatment of finely mineralized ores, is due to a well-devised scheme of mill-treatment, whereby a rough concentrate is usually obtained as an intermediate product, which is then recrushed and reseparated in obtaining final clean products.

Jan 3, 1913

By James A. Burns

The challenge to designers of bulk materials handling systems is to apply the existing technology in areas where it has not been used and to foster better, cheaper and safer job performance. The Dashaveyor Co., a subsidiary of The Bendix Corp., built and tested a pilot system at Copper Range&apos;s White Pine mine. Based upon this success, a prototype system development was begun in 1967 to test the concepts in a full-scale, realistic environment.

Jan 11, 1973

J. J. RUTLEDGE,* McAlester, Okla. (written discussiont).-Research work has often a more immediate and practical application to the in-dustries than even the investigators themselves realize, but coal mining has not attracted the investigator, except in so far as the mine-accident prevention work and fuel investigations are concerned. In future, the coal geologist will study the subsurface geology of the various coal seams as the petroleum geologist now studies the oil sands, and from the results of these studies the coal operator will be able to locate his shafts to the best possible advantage and to avoid faults that would interfere with underground work. There would have been many thousands of dollars saved, and perhaps some reputations, if a good stratigrapher. had been called into consultation in the southern part of Somerset County, Pa., where a local seam of coal, quite thick, was mistaken for the Pittsburgh seam, which, if ever present at that point, had long since been eroded. Why will the Quemanhoming coal carry more sulfur without injuring the grate bars than George&apos;s Creek Big Vein? Only the investigator can answer and yet the fact that the above is true means a greater price for the thinner coal. The owner of the land in Oklahoma receives one-fourth of the cotton crop produced by the tenant who farms his land and one-third of the

Jan 11, 1919

Mining Methods JAY A. CARPENTER, Chairman CLYDE E. WEED, Vice-Chairman ROY A. HARDY, Secretary Alluvial Mining CLINTON BERNARD O. B. PERRY NORMAN CLEAVELAND C. M. ROMANOWITZ R. B. EARLING J. B. STAPLER BENERE H. GRANT CHARLES THURMAN Open-Cut Mining Iron G. E. DIEHL EARL E. HUNNER P. G. HARRISON G. E. LEVEQUE Copper LOUIS BUCHMAN W. H. GOODRICH J. H. DAVIS WALTER S. LARSH

Jan 1, 1941

By C. N. Garman

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

Jan 1, 1962

By Albert R. Ledoux

In Great Britain all analytical chemists are styled assayers, but in the United states a slight distinction is made, assayers being considered those analytical chemists who have chiefly to do with the determination of the precious metals. There have grown up around the assayers of precious metals a number of customs and traditions which, as a rule, do not fetter American chemists when called upon to determine the composition or constituents of any samples submitted to them for analysis. In Great Britain, on the other hand, trade-customs even go to the extent of enforcing the employment of an admittedly erroneous atomic weight in certain alkali-determinations. If the American chemist is asked to determine the amount of lime in a water, potash in an alkali, or silica in an ore, the owner of the sample does not presume to suggest what method he shall employ, nor does he question his report on the ground that he should employ another method. But even in America it is different with the assayer. Unfortunately for the guild, as well as for those who have to base business operations on the reports of assayers, customs and traditions as well as divergent interests seek to circumscribe him in his choice of method and sometimes dictate how he shall perform his operations. This was true at one time of copper, which to-day in England is still determined by the so-called Cornish fire-assay, an attempt to imitate in the laboratory the various metallurgical operations in the smelting-works; but nowhere in this country is the assayer forced to employ any particular method for determining copper so long as his certificate indicates the true total percentage of copper in the sample. It is true that both buyers and sellers demand use of the electrolytic method, but only because it is the most accurate. In America the trade accepts the assayer&apos;s statement as final, and makes

Jan 1, 1895

By J. W. Stewart

THE aim of this paper is to point out the various ways in which design is taught in standard four-year mining engineering curricula in American colleges and universities; to discuss the reasons apparently justifying the great diversity of procedure that exists along this line; and to indicate possible solutions to the difficulties now attending the teaching of design. A study was made of typical four-year mining engineering curricula in 15 colleges and universities of the United States (Table I). Great diversity in content of the various design courses, if taught as described, became apparent immediately. It appeared that it might be both interesting and instructive if the cause for this colorful variety could be found. Was the cause local mining conditions, departmental individuality, or actual necessity? Study of the school catalogues revealed that the various design courses could be classified into two fairly distinct types; namely, (I) those dealing with mine equipment or structures, and (2) those dealing with underground layout of mine workings. It seemed reasonable to label the first type of course "mining design" and the second type "mine design." Some such distinction must have been in the minds of mining educators, for we find both names (i.e., mine design and mining design) used to designate the design courses included in the various mining curricula. Unhappily, the name and the apparent content of such courses do not, in all instances, conform to the classification made here, although in most instances such conformation does obtain (Table I). It is possible that in the exceptional case the method of teaching a design course, and consequently the content of it, may have been changed at some time without change in the name of the course. Apparently only 3 of the 15 schools made an effort to cover both types of design in their curricula (Table I). Two other schools did not list or describe any course of study that could with certainty be taken as a design course. Of the remain¬ing to schools, 9 gave a mining-design type of course and one gave a strictly mine-design type. Obviously, the preponderance of design courses afforded are of the mining-design type. Why? To answer this question, it is necessary to make a study of the prerequisites for the two types of design courses taught. In all schools the design courses were taught in the senior year; in eight, design was taught throughout both semesters; in two, it was taught during the first semester only; and in three it was taught during the second semester only. Consequently, excepting the last three cases noted, it is obvious that all prerequisites for a design course should be completed by the end of the junior year. PREREQUISITES What are the probable prerequisites for the different kinds of design courses as they appear to be taught? Let us take first the case of the mine-design type of course, having to do with layout of underground workings. Here it would seem that logical

Jan 1, 1941