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By H. P. Willard, Conrad Martin

SINCE the deposits were found in 1927 in the Paradise Range of western Nevada, more than 1 mil- lion tons of magnesite and half a million tons of brucite have been mined and processed into a variety of granular refractory materials used as furnace linings by the steel industry. An additional million tons of magnesite were used during World War II to produce magnesium metal, and some magnesium oxide from the area is going into magnesia cements. Located near Gabbs, Nev., on the west flank of the Paradise Range, the principal bodies occupy an area a mile long by half a mile wide, and lesser occurrences have been found in a belt more than four miles long and in places almost two miles wide. Magnesite reserves containing less than 5 pct lime are estimated at more than 25 million tons. Reserves of better grade material are considerably less.

Jan 4, 1957

By Thomas N. Williamson, Victor Zeni

A 6-ft diam core drilling machine has successfully completed seven mine shafts in Virginia and West Virginia to depths as great as 465 ft. There is no practical depth limitation to this new system-a potential method in formations not easily penetrated with other large-scale drilling programs-and higher penetration rates and larger diameters are possible in some formations already being drilled successfully by other methods. The core barrel on the machine is fitted with rolling cutters such as those used on oil field rotary bits, so that less torque is required than with other large- scale drilling systems. The core is made with a wider kerf than is achieved with other coring methods, providing more working room for core drilling.

Jan 4, 1957

By Paul-Emile Mercier

LOADING efficiency depends on cycle capacity of the loader, conditions of the mine, and mine organization. Cost of operation is the final criterion. Two types of loaders are analyzed-the boom shovel and the tractor-excavator. Studies were made in an open pit at Kimberley, Nev., where shovels are the production units and the tractor- excavator is a clean-up loader. The report deals mainly with the analysis of cycle and output. Problems of pit organization are not acute. (Other studies included in the original report and omitted here covered tractor-excavator application underground.)

Jan 4, 1957

By P. E. Landolt

BEFORE World War I, and even prior to World War II, lithium was considered among the rare elements. Mining was limited to exploitation of a few well selected sources of rich minerals recoverable by hand cobbing methods. Within the past five years the situation has changed radically. Many new sources have been explored and developed, principally in Canada, North Carolina, and Southern Rhodesia. The prime raw material for lithium recovery is spodumene. In Southern Rhodesia, however, both petalite, a modified spodumene, and lepidolite, a lithium mica, are being mined in quantity.

Jan 4, 1957

By R. F. Hollis, C. K. McArthur

PRIOR to the application of anion exchange, all recovery of uranium from acid leach liquors precipitated an impure product requiring further upgrading before it could be refined. The ion exchange process, on the other hand, provides excellent selectivity for extracting soluble uranium from leach liquors, so that high grade concentrates can be produced directly. The discovery that uranium is readily adsorbed by anion exchange resins, together with the experience of resin and equipment manufacturers in water treatment, led to rapid development of ion exchange in a multiple column operation. Many processing plants using fixed bed ion exchange are in operation or under construction in Africa, Australia, and Canada. There are a limited number in the U. S. Although the fixed bed process has been highly successful, the feed to the ion exchange columns must be a clear solution, which is obtained by filtration or by countercurrent decantation of leached pulps. With some ores, poor filtration or settling characteristics make production of a clear solution difficult. Most processing plants in the U. S. receive their ores from a number of small mines, and there is considerable variation in the settling and filtering behavior of the ores. An ion exchange process was therefore desirable in which the uranium could be recovered directly for the leached pulp by adding ion exchange resin, which could be then separated from the pulp by a screening operation. The process would thus resemble the cyanide-charcoal process in which gold is adsorbed from cyanide pulp by means of activated charcoal. Preliminary tests in which leached pulps were directly contacted with resin beads led to the development of the RIP process.

Jan 4, 1957

By R. H. Wightman, C. D. Chandler, P. B. Nalle

SURFACE quarrying at the Crestmore Div. of Riverside Cement Co. in California was started in 1909. In the early 1920's it was considered that these deposits were nearly exhausted for the equipment available at that time, and in 1927 the company began a block caving system. This mine continued operating until February 1954. In 1941 trucks and crawler-mounted shovels had reached a stage of development that permitted reopening the quarries in conjunction with the underground mine. In 1948 surface reserves and the well developed limestone of the caving system neared depletion. To go deeper with the caving system was unattractive because of the economics, changes in physical structure of the rock at depth, and the perched water table

Jan 4, 1957

By G. H. Lovell, W. J. Parton, J. J. Crane

IN 1949 Lehigh Navigation Coal began a study to improve its mining methods. At this time the company mines were using conventional breast and pillar and slant chute methods to mine the. steeply pitching coal (40º to 90º). Mining costs were high, the miners' productivity low. There were many hazards typical of the methods employed. Coal seams in the Panther Creek Valley area of the southern anthracite field form a syncline dipping 40" to the south and 75º to 80º to the north, the lowest point 1500 ft from surface. Several contiguous veins 7 to 50 ft thick are mined. Characteristic folding is shown in Fig. 1.

Jan 3, 1957

By Robert G. Van Nostrand, John H. Henkel

TRANSIENT potentials obtained in resistivity prospecting can be separated into two classes. The first is electromagnetic, has a comparatively short time constant, and increases in relative amplitude as the electrode separation is increased. These electromagnetic transient potentials, of which an excellent theoretical treatment is given by Yost,1 are the result of changes in the current and can be classed as differentiated signals. The second class is electrochemical, has a comparatively long time constant, and decreases in relative amplitude as the electrode separation is increased. The electrochemical signals are generated by the current flow itself and can be classed as integrated signals. The transient potentials due to electrochemical factors are the subject of this article. The phenomenon is referred to as induced polarization. Schlumberger2 was the first worker to observe induced polarization, but he was unsuccessful in attempts to apply the principles of induced polarization in electrochemical prospecting. Other workers, notably Bleil3 have studied polarization and in some cases pointed out its possibilities, but no theory has been presented that describes polarization and its time dependence adequately. It is the purpose of this discussion to present the essence of a theory to geo- physicists and to show that it leads to results consistent with experimental evidence. The theory on which this analysis is based has existed in electro- chemical circles since 1910.4

Jan 3, 1957

By D. E. Wolfson, D. A. Reynolds, F. W. Smith

IN 1948 the U. S. Bureau of Mines began a three- phase program to evaluate the extent and quality of U. S. coking coal: 1) a factual appraisal of known recoverable reserves in beds of mineable thickness, 2) a study of preparation characteristics, and 3) a study of carbonization properties. A previous paper presented the methods used in assessing reserves.' Although this investigation is only partly completed, data on coking properties of the Pittsburgh district coals are now available. The results are presented in this article. When coals are selected for manufacture of metallurgical coke more factors must be considered than for any other major use, as no basic industry requires coal of such high quality and uniformity. This is particularly true in the Pittsburgh district, where blast furnace practice is based on use of cokes from high quality coals. Although it is true that inferior coals are carbonized in other industrial areas, both here and abroad, the Pittsburgh coals are the best economically obtainable in the required tonnages, even though they are not the most desirable for metallurgical use.

Jan 3, 1957

By Bruce Short

HIGH rock and surface temperatures combined H with small deep shafts create a difficult ventilation problem. At the Magma operation in Superior, Ariz., booster fans take air off the bottom levels, directing it first through cooling coils and then through the working places and out to the exhaust shafts. All air drawn from the intake shafts below the 3400 level is cooled before it goes to the stoping areas. Most of the ore mined at Magma has come from steep-dipping vein deposits developed for a maximum distance of 9000 ft along the strike of the vein. At present approximately one third of the tonnage is coming from a new section of the mine where the ore occurs as replacement deposits along a favorable horizon in limestone beds. The deepest mining level is now the 4800.

Jan 3, 1957

By C. F. Cornell, Henderson, A. F. Dunyon, D. A. Dahlstrom

IN processing magnetic taconites several steps of crushing, grinding, classification, and magnetic separation are required to produce a 60+ pct Fe concentrate. Usually the final concentrate is in a slurry form of 55 to 70 pct solids by weight and is further characterized by a particle size of 60+ pct -325 mesh. In taconite plants already completed or under construction the conventional method used to obtain pellets suitable for blast furnaces is to filter the concentrate slurry, ball the filter cake, and then harden the green pellets in a traveling grate or in a vertical shaft furnace. Large tonnages must be handled in minimum floor space, with reduced maintenance and lowest possible operating cost. Filtration must therefore achieve two objectives: 1) high filtration rate-in terms of pounds of dry solids per hour per square foot of filtration area-at a low filtrate solids concentration, and 2) a filter cake moisture that will always permit efficient balling within the normal fluctuations of plant operating conditions. If moisture contents are too high, balling may be impossible or result in a mushy ball without enough green strength for the firing operation.

Jan 3, 1957

By Alan E. Gallie

SHERRITT Gordon Co. was formed in 1927 to exploit a copper zinc orebody located in the bush 90 miles north of The Pas, Manitoba. The mine went into production in 1931, operated for a year and a half, and closed because of the low price of copper. Reopened in 1937, it operated continuously until mined out in 1951, producing 8.5 million tons of ore. From 1937 on Sherritt Gordon conducted an energetic prospecting program throughout northern Manitoba, giving particular attention to the belt of favorable greenstone rocks north of the Churchill River. From 1937 to 1941 a number of gold showings were located but nothing of economic value was found.

Jan 3, 1957

By V. N. Antaki

ELEMENTAL phosphorus (referred to as P,) is a true mineral product that has developed, in the relatively brief span of a century, from a laboratory curiosity to a heavy chemical. Annual production now exceeds 300,000 short tons. Continued rise in production has been predicted, consistent with new applications for P, derivatives and the expected population increase. In itself elemental P, is valuable chiefly as an 'intermediate chemical. The principal end uses at present are in inorganic phosphates, both simple and complex, of sodium and potassium, used in water treatment and detergent compounds, leavening agents, food supplements, and dentifrices. Organic P, compounds are important as plasticizers, oil additives, flotation agents, and more recently as gasoline additives (TCP being the outstanding example). The increasing use of high-analysis water-soluble and liquid solution fertilizers, as well as the direct application of phosphoric acid to the soil, will probably be the most significant factors in P, production growth rate. Coke oven plants now using sulfuric acid to fix byproduct ammonia values will gradually switch to phosphoric acid in order to market a fertilizer with completely available values. Recently sponsored experiments show that phosphoric acid can be directly admixed with cattle and poultry feed to produce rapid growth. Both P, compounds and modifiers for oil well drilling mud show increasingly promising significance.

Jan 3, 1957

By A. F. Peterson

MUCH has been said and written about the engineer shortage. The mining branch in engineering has lagged during the past several decades. I can think of two institutions, formerly prominent in that field, that have discontinued this department and another that has branched from a purely mining school into various forms of engineering. Conversely, I do not recall any institutions that have added mining to their curricula. I believe that this action is in direct response to the demands of incoming students. But I also believe that while there is a specific demand for civil, mechanical, and electrical engineers in the highly complicated mining operations of today, our need for mining engineers capable of assuming top responsibility for mining operations is unchanged.

Jan 3, 1957

By P. W. Guild

DURING 1956 the application of geology and related scientific disciplines to the search for new mineral deposits went forward on an ever widening front. Spurred on by record-breaking consumption of many of the established commodities and new uses for minerals and metals that were hardly known a few years ago, the profession is figuratively leaving no stone unturned in the effort to insure that adequate raw material supplies will be avail- able for the future. More money was spent and more people were engaged along more lines of research than ever before. A huge project to map much of the Canadian Shield area by photogeologic methods stands at one extreme; application of isotope ratios to ore finding stands at the other; between them the more traditional techniques are being increasingly refined. In the Fiftieth Anniversary volume of Economic Geology, published late in 1955, Alan Bateman sketches the development of fundamental concepts as recorded in the pages of the journal over the first five decades. An additional 24 review articles cover individual aspects of the field and constitute a base for further advances.

Jan 2, 1957

By Norman Weiss

IF we were to measure progress this year in terms of large new mills and discoveries of fundamental significance we should certainly be disappointed. Outside of the uranium field there was little of a spectacular nature. San Manuel and Reserve completed their first year of operation; Erie approached readiness; the Toquepala project in southern Peru broke ground and gained speed. Important mill enlargements occurred at Inspiration, Anaconda, Ray, and Climax Molybdenum. A 3000-ton copper concentrator was completed at Pima, near Tucson. The Republic Mill of Marquette Iron Mining Co. started up in April. Abroad, the great developments in the African Copper Belt can be likened to the rapid growth of the porphyry coppers in this country. Fundamental research was confined nearly entirely to iron ore flotation and recovery of metal values from leach solutions, particularly uranium. The large number of review articles this year reflected a desire to take stock and consolidate past gains before taking the next bold steps. Undoubtedly a shortage of competent young engineers and technicians is stunting the natural growth of theoretical investigation in the field of minerals beneficiation, as well as the conversion of ideas into action. We find our small stock of talented young scientists concentrated in a few centers of erudition because there are not enough to diffuse through the industry. It is safe to say that among mine administrators and managers there is more interest in the education, training, and welfare of the young engineer than ever before.

Jan 2, 1957

By John G. Hall

MANY millions of tons of raw materials are removed each year from open pit mines in the eastern U. S. These materials are used by industry to produce aluminum, asbestos, barite products, building stone, cement, crushed stone, copper, coal, dolomite, garnet, iron, limestone, mica, phosphate, phyrophyllite, titanium products, and wollastonite. Improvements in open pit mining techniques through the years have made open pit mining more and more attractive as compared to underground methods. Today ore deposits that formerly would have been mined underground have proven to yield more profit if mined by open pit methods. Ever-rising labor and material costs have made equipment capable of high-volume production and low-unit cost-and supplies rendering low-unit costs-not only attractive to open pit operations, but essential to their economic existence. During the past year, the major advances have been in drilling and blasting operations, and the application of large capacity materials handling equipment. Mining men from the Great Lakes, Northeast, East Central, and Southeastern regions of our country tell in the following articles of the trends in open pit mining in their areas during 1956.

Jan 2, 1957

By Ralph C. Holmer

IN the field of mineral exploration, 1956 can be looked upon as the International Geochemical Year. This is not because of unusual developments in geochemical prospecting but rather because of the world-wide effort in geochemistry and the realization that geochemistry is now an established exploration method. Use of mining geophysics has continued to increase. Those extensively employing exploration techniques indicate that developments of the past few years have permitted better programming of methods, from reconnaissance to location of drill- holes. There is greater diversification of methods- reliance is not placed on results of one. However, it is realized that often it is more economical to drill an anomaly than to conduct additional expensive geophysical surveys

Jan 2, 1957

By Hugh Steele, Brower Dellinger

U. S. mining trends for 1956 continued steadily U+ S. uphill, technique and equipment advanced with the pull, and exploration and development of once mined districts attracted more attention than new areas. Expansion of the Ambrosia Lake district in New Mexico more than doubled known uranium ore reserves, and production began from several of the large new ore discoveries. In Canada the up trend was more spectacular, especially in exploration and development. To combat increasing problems arising from high labor costs, taxes, low grade orebodies, and dwindling discoveries, manufacturers and mining companies have continued to introduce new techniques and new products-reamer bits for enlarging small holes drilled by jacklegs, whup d'whups for drift mucking, Cryderman machines and over-the-head small crawler-type machines for shaft mucking, the 20-ton TL 220 four-wheeled tractor trailer unit for underground haulage, inertia-type dust collectors, roof bolting in conjunction with chain link fencing for wall support, wooden roof bolting using compression support of ground for wall support, and new one-use carbide bits.

Jan 2, 1957

By George A. Lamb

AMONG the main interesting developments in the coal market have been the changes that have taken place between the consumer groups. Important signs of these changes began to appear many years ago, but in a modest way, and were apparent only to the few fuel experts making broad statistical determinations. It is doubtful, however, that any of these experts appreciated the significance of their early findings, and perhaps none had the imagination to consider how extensive these changes might be eventually with respect to solid fuels sales and distribution. (Reference here will be principally to bituminous coal.) Railroad Fuel Major changes in coal use did become pronounced after World War II, and it did not take an expert to see what was taking place and how serious the impact was likely to be. First, was the case of the steam and diesel locomotives. The railroads had been considered the best coal customers; they were steady and large purchasers and usually paid a better price than most others. Railroad fuel provided the basic mine realization and it often was the source for operating cash during general market slumps. It was the outlet for 20 pct of the bituminous coal production, as much as 110 million tons in 1946.

Jan 2, 1957