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With a mine output as high as 5000 tpd and mill capacity of 7000 tpd, the uranium mining and milling complex owned and operated by Kerr-McGee Nuclear Corp. in the Ambrosia Lake area is the largest in the U.S. and is likely to remain so for some time. Next year, Kerr- McGee expects to have in production another mine in Section 19 of the Ambrosia area-and will begin ore production in 1976 at its new $15-million mine at Church Rock, located northeast of Gallup, N. M., where the company has already completed the shaft work and is in the early stages of project development. Ore from Church Rock will be transported to the company's facilities at Ambrosia Lake for processing. Kerr-McGee's existing eight mines in Ambrosia Lake go to depths of about 800 to 1500 ft to tap the various horizons of uranium-bearing sands in the Westwater Canyon of the Morrison formation.

Jan 8, 1974

By AIME AIME

Maurer's review summarizes quite thoroughly the various theoretical developments and experimental findings that contribute to the knowledge of rock mechanics in drilling. This discussion supplements Maurer's paper by including generalities that either have been incompletely treated in his review, or formulated from new considerations by the discussant and from hitherto unpublished experimental data. These generalities are associated with the observation that all mechanical methods of rock drilling essentially comprise a sequence of indexed, concentrated loadings on the bottom of the hole being drilled.

Jan 1, 1967

By H. R. Green, D. M. Lamb, A. D. Taylor

The design of slurry launders has usually been based on strictly empirical concepts. An examination of the most common procedures reveals that they do not account for many of the variables that are recognized as significant for slurry transport. These may include flow rate, volume concentration of solids, solids specific gravity, solids size distribution, particle shape, launder geometry, and roughness of the wetted surface. It was decided to develop a design procedure, which would accomplish two things: First: Take into consideration most of the known significant variables and systematize the procedure to assure consistent results. Second: Provide a rational basis for examining and utilizing operating data to refine and improve the system. To accomplish this, it was necessary to develop a basic design concept. This concept has been developed through a complex development history, and yet still appears workable and technically sound. That concept may be outlined as follows: First: The solids transport velocity is the fundamental basis for slurry launder design. Second: The stream configuration, hence the launder size, is integrated with the solids transport velocity so that the actual stream velocity exceeds the solids transport velocity. Third: The launder slope is that which will achieve the

Jan 1, 1979

By Sidney H. Haughton

FOLLOWING the discovery of diamonds in 1870 and the Witwatersrand gold fields in 1886 South Africa changed from a predominantly pastoral country with a scattered white population into a land whose economy came rapidly to be based primarily on mining. The total value of the mineral output of the Union in 1944 was approximately $493,000,000, to which gold contributed 84 per cent. Gold furnished some 33 per cent of the Union Government's total revenue in that year, and approximately half the country's population obtained its livelihood directly or indirectly from the gold mining industry. In any review of the Union's mining activities and in any consideration of the country's future, gold mining must occupy a prominent place. It is generally conceded that the present structure is not properly balanced and that an economy based on a preponderance of a single nonpermanent factor possesses potentialities of serious instability.

Jan 1, 1946

By Ernest J. Stocking

ENGINEERS are the key men in our war program today. Upon the technical knowledge and skill of the engineer and upon his administrative and executive abilities rests the entire success for the production of vital materials of the war. Naturally the work load of the engineering examining unit of the U. S. Civil Service Commission has increased greatly since our active participation in the war. At present, over 550 separate requests for certification of eligibles are received by the engineering unit per week. These represent more than a fourth of the total requests received for personnel by the Commission's central office at Washington and represent a recruitment work load of three to four times that carried by the whole Commission previous to January 1940. These requests represent a minimum of a thousand vacancies to be filled each week, while an average week will produce, at present, approximately 1400 vacancies and a weekly maximum may approach well over 2000 vacancies.

Jan 1, 1942

By AIME AIME

INSTITUTE members attending the Annual Meeting in New York who want to see one of the mining engineers' newest aids, photoelastic stress analysis, are due for an interesting afternoon on Thursday, Feb. 15, when open house: will be held at the Columbia University mining laboratory. Information as to the direction and distribution off stresses in mine structures, which has been developed by Professor Bucky, associate professor at the Columbia School of Mines, and David Sinclair, research assistant, is useful in the design of pillars and in the placing of openings relative to working places such as gangways and haulage levels.: This work has been sponsored during the last ten years by the Engineering Foundation.. It is fully reported in T. P. No. 1140.

Jan 1, 1940

By Charles Janin

ONE of the most interesting features of the world's platinum situation has been the steady increase of Russian production, which had dropped to 11,000 oz. in 1920, but increased to 92,000 oz. in 1926, and to probably over 100,000 oz. for 1927. It is ex-pected that Russian production of platinum will, be-fore long, closely equal its pre-war production, or approximately 200,000 oz. annually. The world production before the war was around 250,000 oz.; that for 1925 has been estimated at 160,000 oz., and for 1926 probably 170,000 oz. The consump-tion of platinum has, however, decreased. The esti-mate of the International Selling Agency was a de-mand of 130,000 oz. new platinum against a normal pre-war demand of over 200,000 oz. The high price of platinum during the war gave an added impetus to the search for substitutes for the metal, and sev-eral were developed that are now used extensively in place of platinum. The demand for platinum for high-class jewelry, however, was not greatly affected by the high prices, but "white" gold did replace platinum in the cheaper jewelry. Colombia is the most important producer of plati-num, next to Russia, and the production has increased from around 10,000 oz. pre-war production to 55,000 oz. or more in 1927. In 1924 important discoveries of platinum were made in South Africa. Prior to these discoveries practically all platinum was recovered from alluvial deposits, and the South African opera-tions are first to work an ore profitably for the pri-mary recovery of platinum. A number of companies were formed to develop these deposits, but only a few made any real progress. Total production for 1926 was about 5000 oz. The United States production is unimportant; that in Canada has increased to around 9000 oz., principally as a by-product in nickel-copper ores.

Jan 5, 1928

The selection of a particular machine for production drilling is the most critical drill evaluation the pit engineer is called upon to make. It is a true engineering design problem requiring value judgments. Generally, the procedure follows these steps: (1) Determine and specify the conditions under which the machine will be used, including such service factors as labor, site, weather, etc. (2) State the objectives for the rock-breakage phases of the production cycle of operations--considering excavation and haulage restrictions, crushing capacity, production quota, and pit geometry-in terms of tonnage, fragmentation, throw, etc. (3) On the basis of blasting requirements, design the drill-hole pattern (hole size and depth, in- clination, burden, spacing, etc.) (4) Determine the drillability factors and select the drilling methods which appear feasible for the kind of rock anticipated. (5) Specify the operating variables for each system under study, considering drill, rod, bit and circulation fluid factors. (6) Estimate and compare performance parameters, including costs. Major cost items are bits, drill depreciation, labor, maintenance, power and fluids. (7) Select the drilling system that best satisfies all requirements with the lowest over-all cost.

Jan 10, 1967

By Sherwin F. Kelly

LITERALLY from the four corners of the earth, from Jerusalem and China, from Mysore and Uganda, as well as from geophysicists in the United States, came contributions from workers in magnetic and electrical geo-physical methods, most of them unfortunately unable to be present themselves. The most lively discussion centered on the phenomena of natural potentials in the earth, dealt with in M. B. R. Rao's paper from Mysore, and in Parke Dickey's contribution, which he presented in person. In the oil fields, the weak potentials observed in sedimentary strata traversed by bore holes have traditionally been ascribed to phenomena of electro-filtration and electro-capillarity. Research tending to refute this theory was presented by Dickey, who reported the existence of natural potentials in core samples, and between strata exposed in underground workings. This precipitated a lively discussion as to the possible role of electro-filtration, selective adsorption of ions by mineral particles, and electrolytic potentials, in the production of this phenomenon.

Jan 1, 1943

By W. O. Philbrook, A. H. Jolly, T. R. Henry

In the course of a study of slag-control methods, the authors devised a laboratory technique by which the basicity of basic open-hearth furnace slags could be estimated with sufficient accuracy to make the method of possible interest for slag-control purposes. The process consisted of measuring the slight basicity of an extract of the powdered slag in water. The procedure was presented, for the benefit of those who might care to experiment with it, in a paper submitted in the 1944 McKune Award Contest and presented at the 1944 Open-hearth Conference in Pittsburgh.' Interest expressed at that meeting and favorable operating experience with the method at a neighboring plant, as described in a related paper by Michael Tenenbaum and C. C. Brown,; have encouraged us to present further details of the development, technique, and pitfalls of the method and some additional data not included in our first report. At the outset it must be admitted that this method of estimation of slag basicity is not perfect; neither is any other that we know of. It is subject to somewhat greater errors than would be desirable, but compares favorably with other techniques in this respect. It has the disadvantage that it places the final determination of slag basicity in the hands of a laboratory technician rather than the furnace oper- ator, although it can be operated in a control laboratory adjacent to the furnaces. It requires close attention to certain details, as do most laboratory procedures. On the favorable side, it eliminates the "human factor" of personal judgment inherent in estimation from pancakes or powdered samples. The procedure can be placed in practice much more rapidly and presents much less of a training problem than visual methods of estimation. The principle and operation of the method are so simple that it would not be surprising if others have experimented with the same or similar procedures, but we are not aware of any prior publication of details. Our own shop has been operating fairly successfully for several years with the aid of slag pancakes. Since the past year or two have not been favorable for the expenditure of time and energy where the need was not urgent, we have not introduced the new practice for actual slag control and hence do not have extensive operating data. In presenting this method, therefore, we make no claims as to theoretical justification nor guarantees as to practical applicability, but offer it as an empirical observation. We believe it has sufficient merit to warrant its investigation by those just instituting a slag-control program or in search of supplementary methods for judging slag basicity Principle of the Method It is well known that when burnt lime or slaked lime is shaken up with water it

Jan 1, 1945

By CHARLES SIMENSTAD

COAL preparation, or coal washing, is not a new subject to the Pacific Northwest. Most of the coals mined in this state smaller than lump, and nearly all such sizes mined on the Pacific slope of the Cascade mountains, require washing before marketing. A large proportion is being put through some washing process, but coal washing in this state, has not reached the efficiency it is practicable to obtain. In fields where the coal, as mined, contains less impurities, where working conditions make it practicable to eliminate some of these impurities under- ground, or where a large proportion of the run-of-mine coal is lump, coal preparation does not present the problem it does in our local field. Here the coal is associated with considerable impurities and the slack, or steam sizes, aggregate about 80 per cent. of the output. Therefore, approximately 80 per cent. of the coal mined must be washed to become a valuable fuel. Washing then becomes a major operation, as hand picking of the 20 per cent. of lump is a standard and comparatively simple operation. Some coal beds here are so interstratified with bone, of a more or less massive nature, that hand picking of lump is not economically efficient. In such cases the coal must be crushed fine enough for it to be freed from the bone, so that the two may be separated. Coal cleaning in this field, therefore, must receive skilled attention to purify this fuel and raise its stand- ard. Without greater efficiency in cleaning, the importation of coal from outside the state will be even greater than in the past.

Jan 1, 1926

By AIME AIME

MONDAY, Feb. 21, evokes memories of the Silver Corridor at the Waldorf to be recalled and reflected upon for time to come when thoughts drift to the Annual Meeting of 1944. Crowded though it was, on occasion there lurked in the mind's eye a vision of what might have been had the 2886 persons who put in an appearance at one time or another milled around in the lobby of 29 West 39th Street. Some confusion resulted from difficulty in locating meeting rooms, but for the most part everyone found what he wanted. The usual bulletin board of members registered was missing this year and rumor has it that tile Waldorf didn't approve. Registration broke all previous records with many a busy engineer realizing that the program had something to offer that would be of use in his particular job. It might be noted here that "Arpad" co-operated nicely, previewing spring days on Monday, Wednesday, and Thursday; Tuesday was a bit damp.

Jan 1, 1944

By H. LIVINGSTONE LMAN

A GOOD DEAL of information concerning flotation has come out during the patent litigation of recent years, and the legal situation has cleared considerably, to the satisfaction of Minerals Separation, Limited. Hence, Mr. H. Livingstone Sulman, one of the originators of the successful process of that company, felt at liberty to explain, on Thursday, Nov. 20, his experience and his views in a "Contribution to the Study of Flotation," before the Institution of Mining and Metallurgy. He did not give technical details. He dealt with the physical problems, so simple, as he remarked, that he had wanted 96 pages to express his views. He presented much data, partly new and based on observations of his own, bearing upon the very complex flotation phenomena in an instructive wav and made frequent references to the valuable researches especially of Prof. Edwin Edser and Mr. Emil Hatschek.

Jan 1, 1920

By Merlin H. Aylesworth

THE subject assigned to me is peculiarly appropriate to the anniversary of the birth of Abraham Lincoln. If we applied to our present problems the ideals and methods of the Great Emancipator, the future of American institutions would be so definitely assured that there would be little need to discuss the matter. The only inquiries would relate to the pace of progress, not to the possibility of progress. As a nation we have grown more and more to revere the memory of Lincoln, to honor his character, to extol his teachings and to eulogize his concepts of democracy. We rec-

Jan 1, 1940

By H. Wilhelm, E. L. Davis, W. A. Clark

MATHEMATICAL formulas for the analysis of the behavior of producing oil wells can be devised which will be correct for the assumed conditions. However, in an oil zone, variables always exist which are unknown, or to which. it is impractical to assign mathematical values. It seems apparent that one should reason back from observed facts to an analysis of causes, rather than start with a hypothetical reservoir with assumed properties and attempt to explain observed phenomena. In this paper we hope to throw some additional light on factors influencing production, especially edgewater behavior. OIL and gas are contained in reservoirs of either the sealed type or the edgewater type. In the former all the recoverable oil is produced by gas expansion only. In this type of reservoir, edgewater is not effective. This may be because of faulting or overlapping strata, or more often, probably, the edgewater pressure is ineffec¬tive on account of resistance or lack of head.

Jan 1, 1933

By D. R. Mitchell

FOR the second consecutive year, attendance at the Coal Division sessions far exceeded exoectations. Those in charge were continually faced with problems of finding seats and space for attending members. 115 seats were set - II~ for the annual luncheon meeting of the Division and approximately 175 members showed un. Since the hotel management would not serve more than the 115 it meant that 60 members were forced to eat elsewhere. This created hard feelings with some members. How- ever, officials of the Division were not able to obtain in advance any indication of this overflow crowd, but are suggesting to the New York Office that some means other than ticket sales be adopted to obtain an estimate of Division luncheon and dinner attendance. Members could be circularized prior to he meeting or they could be checked when registering as to the events they expect to attend. Under the inspiring leadership of Cadwallader Evans, Jr., Chairman, the Coal Division had a phenomenal growth during the year. Reporting at the luncheon meeting, Newel1 Alford stated that approximately 190 new members had been obtained. A few more years of continuing increase at this rate will make the Coal Division one of the largest Divisions in the Institute.

Jan 1, 1944

By Yu A. Chernegov

Building up the USSR's economic strength was the result of all the achievements and successes of our economy. The Soviet Union was the first to begin planned guidance of the economy. The mining industry of the USSR, which holds the first place in the world output of mining production, has always been considered as the main raw materials basis of the country's economy. High and stable development rates are a feature of planned economic management, based on the social ownership of the means of production. During the past ten years from 1965 to 1875 the national income used for consumption and accumulation increased practically by 1.9 times. There has been no inflation, no unemployment in the Soviet Union for about forty years already. High and stable growth rates of the production of mining industries and that of the branches, which are their direct consumers are characterized by the data in table I. The achievements and successes of the economy's development are to a great extent determined by the three planning components, which are as follows:

Jan 1, 1977

By G. W. LAAiIBOURNE

FEW mines possess a history of more fascinating interest than the Ontario at Park City, Utah. The famous Bonanza's production record of over $50,000,000; the great extent of its workings; the remarkable character of its mineralization; the fact that recent discoveries have shattered preconceived theories of the geology of the camp practically assuring the half-century old property a future as active and as prosperous as the past make the Ontario one of the unique mines of the world. A mere accounting of the wealth created by this historic property not only exemplifies the great profits

Jan 1, 1925

By Tegner C. Johnson

Just a few years ago, my company was referred to as the Marion Steam Shovel Company. Though we still make shovels, both two and eight-crawler types, the eight-crawler stripping shovel appears to have been replaced by the walking dragline for overburden removal and in some cases for the mineral as well. The walking dragline appeared in the coal fields in the early 1930's. It is popular because it can cope with overburden depths in excess of 100 ft and with blasted sedimentary rock, all at an O & O (ownership and operational) cost of ±10[c] per bank cu yd (bcy).

Jan 10, 1974

By R. G. Bowman

LEAD is a dull and sober metal, and in times of economic stress it en- joys, or at least occupies, a position which partakes somewhat of its physical lethargy and stability. The past ten years have witnessed in this country a decline in the production of lead, and a shrinkage of ore reserves, following closely the general economic situation. Metal prices have not justified exploration and development of new sources. Momentary rallies in industry have brought no response from lead.

Jan 1, 1940