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The saying that a "prophet" is without honor in his own country does not always hold true, as is shown by the following from one of the local papers, which appeared under the above heading: "Edwin Ludlow, for more than seven-years vice-president of the Le-high Coal.& Navigation Co., with headquarters in Lansford, has resigned, to take effect July 1, when he will take up his residence in New York and engage as a consulting engineer. Mr. Ludlow, during the incumbency of his present position, has demonstrated his efficiency as an engineer and general manager in many directions, notable among which are the almost perfect methods in practice in the inside workings of the several operations under his charge and the erection of the most complete, most practical and most commodious breakers for the preparation of the mine product for market. In addition, his relations with organized labor have been cordial and his dealings with its representatives have been invariably based upon the principle of fair play."

Jan 7, 1919

By S. L. Hoyt

ABOUT three years ago eight standard steels were prepared for the cooperative investigation of methods for oxygen analysis, sponsored by the Iron and Steel Division of the American Institute of Mining and Metallurgical Engineers and by the National Bureau of Standards. A preliminary report of the results was made at the annual meeting of the A.I.M.E. in February, 1936. ? This report showed the reliability of vacuum-fusion methods and further brought out certain advantages of the fractional vacuum-fusion method. The results obtained by the authors with the latter method will be discussed here, with some com-ments on the procedure for those who are interested in determinations of gases in steel. Some additional comments are offered on the use of the polarizing microscope for identifying the inclusions in the steel to check and amplify the findings of the fractional vacuum-fusion analysis. For details of the fractional method, see the paper by L. Reeve1.

Jan 1, 1937

By J. F. Abel, F. T. Lee

Subsidence is controlled by a complex com¬bination of mining and geologic factors. For example, a compilation of worldwide data shows that, as the percentage of shale in the overlying rock mass decreases and the amount of sandstone increases, the angle of draw (and the area affected by subsidence) decreases. Limestone in the over¬burden appears to cause a more than twofold decrease in the angle of draw compared to a like amount of sandstone. Increased amounts of sandstone were accompanied by a greater surface subsidence relative to the mining height. The total thickness of overburden did not appear to influence the subsidence magnitude above super-critical panels. The greater the thickness extracted, the smaller percentage of that thickness shows up at the surface as subsidence. The greater the percent of the seam extracted, the greater the subsidence reaching the surface. The maximum subsidence above room-and-pillar panels de¬pends on the pillar height and minimum width as well as the other factors listed.

Jan 1, 1984

Idaho Bureau of Mines and Geology, University of Idaho, Moscow, Ida. John W. Finch, Director. A list of publications will be sent upon application. A series of Bulletins and Pamphlets have been issued by the Bureau to date since 1920 Of the Bulletins, six are out of print, and a charge is made for eight. Each of the Bulletins, in the main, treats of the geology and resources of a particular district in Idaho, as follows (only available Bulletins listed): Bulletin 1, South central Idaho (1920), 15 cents, 7, North central Idaho (1924), 50 cents, 8, Bonneville, Bingham and Caribou counties (1924), 50 cents, 9, Boise Basin (1924), 50 cents; 10, Boundary County (1926), 50 cents; 11, Region about Silver City (1926), 50 cents; 12, Clark Fork district (1930), 50 cents, 14, Eastern Cassia County (1931), 50 cents, Press Bulletin 15, Teton County (1927), Bulletin 16, Melon Valley near Buhl (1927); 17, Concerning land slips near Whitebird, Idaho (1928) The 37 Pamphlets are issued free of cost, and each treats, also, in the main of the geology and resources of a particular district in Idaho Nos 1, 2, 3, 4, 5, 7, 8, 10, 17, 18, 20, 22, 25, 26, 30 and 35 are out of print Of those available, attention may be called to Pamphlet 6, Reported platinum occurrences near Coeur d' Alene (1925), 11, Bruneau River Basin, 12, Power and Oneida

Jan 1, 1933

By A. J. Boyer, T. R. Meadowcroft

An experimental determination has been made of the efject of surface diffusion on the vapor pressure obtained in a Kwudsen cell. The results show that a knife-edge orifice in a molybdenum lid may give erroneous results for the vapor pressure of silver. when a correction suggested by winterbottom and Hirth is made, the results become meaningful. Experimental work with cylindrical orifices in molyhdenz~m lids and knife-edge orifices in ceramic lids shows that good vapor-pressure results may he obtained when the orifice is designed so that ejfusion is the only significant source of weight loss. THE Knudsen effusion cell technique has been used by many investigators to study relative and absolute vapor pressures over metals and alloys at elevated temperatures. As a result of this interest, some theoretical studies have been made of geometric factors affecting effusion from the orifice of a Knudsen cell. A review of these studies has been made by Margrave.1 Recently, Winterbottom and Hirth2 have suggested that a physical effect, that of condensation, surface diffusion, and re-evaporation, may seriously affect Knudsen cell measurements, especially when a knife-edge orifice is used. Inasmuch as many of the present vapor-pressure data have been obtained using knife-edge orifices. it was felt that an experimental evaluation of the effect of surface diffusion on Knudsen cell measurements would be of value both in the design of the cell orifice and in establishing realistic estimates of the limits of error for existing data. The experimental program was in two sections. Firstly, measurements of the vapor pressure of silver were made in cells with cylindrical and conical orifices in which the surface-diffusion contribution to the weight loss should be negligible. These results were correlated with existing data to give a reliable measure of the real vapor pressure of silver. Secondly, measurements made using knife-edge orifices were corrected using the surface-diffusion theory of Winterbottom and Hirth2 and were then compared to the real values. The experimental arrangement is shown in Fig. 1. The balance was an Ainsworth RV-AU-1 automatic recording microbalance capable of measuring weight changes of ±0.02 mg on a total load of up to 100 g. The temperature was measured by an optical pyrometer signted on the bottom of the suspended crucible. The temperature readings were calibrated in a separate experiment in which pyrometer measurements were made while at the same time thermocouple readings were taken of the temperature at the inside top and bottom of the crucible. The range of reproducibility with this technique was ±4°C. A constant voltage source maintained a temperature of ±2°C at 1200°C over 10 hr. Silver of 99.99 pct purity was used in nonporous alumina crucibles. Lids of molybdenum, tantalum, or magnesia were cemented to the crucible using a sodium silicate cement. Table I shows the characteristics of the lids used. The vapor pressure is obtained using the basic Knudsen formula:

Jan 1, 1965

By W. M. Phillips

Processing kaolin clays from the sedimentary deposits of Georgia and South Carolina is described in this article. While the major processing steps are touched on briefly, emphasis is given to the dewater-ing of the clay-water slurries (slips) formed in the processing of kaolin clays. The dewatering steps discussed include gravity settling, centrifugal dewatering, vacuum filtration and thermal drying. Particular attention is given to vacuum filtration and the variables affecting filtration of these kaolin clays. Kaolin consists essentially of the mineral kaolinite, which is a hydrated aluminum silicate (Al2O3 . 2SiO,). Commercial deposits of kaolin occur in several areas of the U. S., but approximately 90% of the kaolin produced in this country comes from Georgia and South Carolina. These deposits are of sedimentary nature and occur in a geological fall line in the Tuscaloosa formation at elevations between 300 and 450 ft above sea level. Over two million tons of kaolin clays are used by industry in the U. S. each year. A big percentage of this tonnage is used in the paper industry for coatings in making glossy and high quality grades of printing papers. In addition, large tonnages are used as pigments; as fillers for rubber, plastic and fertilizers; and in ceramics. Properties of kaolin that make it widely used in the above applications are its particle size fineness, natural whiteness, chemical stability and non-abrasiveness. In addition to these desirable properties, it is relatively inexpensive. The finer coating grades of clays range in price from $15 to $28 per ton while the coarser filler grades sell within a range of $7 to $13.50 per ton. Pure kaolin particles are small hexagonal flat platelets. Above the 2-p size, the particles usually consist of stacks of plates, while below the 2-p particle size they occur as individual flat, hexagonal plates. Since these individual platelet particles provide the most desirable coating and flow characteristics, major importance is given to particle size fractions of 2 p and smaller. Generally, coating grade clays are those with all particles smaller than 15 p and at least 70% of the particles less than 2p. These coating grades also have 50% or more of the particles smaller than 1 µ in size. The extremely fine grades of coating clay currently being produced approach the range of 100% smaller than 2p. The filler grades of kaolin have 100% of the particles passing 325 mesh but have less than 70% of their particles below the 2-p range. Fig. 1 is a schematic representation of the major processing steps involved in preparing kaolin clays for marketing. MINING All kaolin mining is open pit. The ratio of overburden to clay will average 3:1, but this ratio can, of course, be much higher depending upon the grade of the clay and the size of the deposit. Most of the commercially mineable deposits occur from 20 to 120 ft below the ground surface. Both draglines and pans are used in removing the overburden and mining the clay deposit itself. After mining, the most common method of transporting the clay to the processing plant is by blunging or re pulp-

Jan 1, 1963

By R. E. Hurst, D. E. Ramsey, J. M. Moore

The "frac" method of well stimulation has been applied successfully to all producing formations in the Permian Basin area. During the five years since its development, many changes and improvements have been made in treating materials. procedures, and equipie11t. A number of fluid carrying agents, having different physica1 and chemical properties, have been developed to meet variorus well requirements. The current trend is toward larger gallonage treatments, employing higher injection rates. The use of "down-the-casing" techniques has greatly reduced high surface working pressures, attributable to friction losses resulting from injection throrugh tubing. Petrographic studies of various Permian Basin formations, coordinated with laboratory and well log data, have been found a valuable guide in planning frac treat111o1t.s. A knowledge of the extent (and orientation of naturally occurring fractures and planes of weakness in the formation, aid in predicting the ultimate drainage pattern resulting from the frac treatment. INTRODUCTION The South Permian Basin covers an area in Wcst Texas and New Mexico about onc-half the size of the state of Texas, This vast region has been called the "Permian Basin" for so long that the term will he used here. It includes an area south of the Matador Arch. approximately 250 miles wide and 300 miles long. Structural features of importance within the basin are the Northwest Shelf, Eastern Platform, Midland Basin, Central Basin Platform, and Delaware Basin. The principal producing formations include sand, limestone and dolo-mite, with lesser amounts of shale, anhydrite. chert. and various silicates. All of the producing formations in the Permian Basin have responded to some type of frac treatment. Essentially, a frac treatment may be defined as the injection, into a formation. of a fluid carrying agent containing a particulated solid (usually sand), for the purpose of increasing production. The application of this method of well stimulation to many differing Permian Basin reservoirs has necessitated numerous changes and improvements in carrying agents, solids, service equipment. well equipment. and treating techniques. CARRYING AGENTS A number of different types of fluid carrying agents have been developed since the introduction of the frac method of well stimulation. These agents have different physical and chemical properties, and in many cases the extent of production increase derived from the frac treatment depends on the choice of fluid carrier. Unfortunately, due to many different systems of nomenclature used in the oil field, these differences are not always recognized by the oil Operator. In general, carving agents may he divided into the following broad classi-

Jan 1, 1956

By Charles H. Mitchell

British Columbia is enjoying a period of sustained high-level activity in all aspects and sectors of its mining industry. The total value of mineral production for 1962 was in excess of $229 million. This was the greatest total value attained for any year to date, exceeding the previous record year of 1956 by more than $40 million. It appears reasonable to expect that value of production for 1963, stimulated by increased production attained during the year, and by improved metal prices for some of the major products, will be substantially in excess of that recorded for 1962. Elsewhere in this issue appears a detailed report of prospecting and exploration activity in the Province. For the purposes of this review it is sufficient to state that the level of prospecting and exploration activity during the past several years has been greater than at any previous time and that there does not appear to be any slackening in activity or interest.

Jan 12, 1963

By P. R. Hanes

A description of the methods used in driving two tunnels, 2 miles long each, one a 9-ft. and the other a 19-ft. diameter section, for the Owyhee Irrigation Project, Oregon. One heading of the smaller tunnel was driven 1315 ft. in 73 shifts in one month and 10,966 ft. of this section completed in ll½ months using two shifts for eight months and three shifts the rest of the time. This is a good illustration of the proper use of a mechanical shovel and the importance of careful selection of supplernentary equipment to secure best results. Large cars, speedier and heavier locomotives, 36-in. gage track of 45-lb. rail, and a good switching method increased actual shoveling time and cut down muck removal period about 45 minutes from average. The larger tunnel, after trying out standard electric revolving shovels of both the rail mounting and caterpillar tread types, was excavated with a mechanical mucker. This is the first time that a tunnel of so large a section has been handled this way. This record work was accomplished without drill carriages.

Jan 1, 1934

By Wallace Ralston

The East Texas area includes the northeast 38 counties of the state of Texas. It covers all, and extends beyond, the borders of what is commonly described as the East Texas Basin. It is one of the most important oil and gas-producing areas of the Mid-Continent Province. It includes four important oil fields—Van, East Texas, Cayuga and Long Lake— and the recent extension of Rodessa field into Cass County, Texas, may prove to be of major size. Four commercial gas fields are in this area— Bethany, Waskom, Cayuga and Long Lake. Up to January, 1936, all of the oil has been produced from the Upper Cretaceous formations, and most of that from the basal member, the Woodbine sand. Gas is produced from both the Upper and Lower Cretaceous formations. Development in Fields East Texas Field.—This field continued to dominate the drilling and production situation throughout the United States. There were 4036 wells completed in this field during 1935; that is, 365 more wells than were completed during 1934. Drilling activity was due to close spacing of wells and the addition of 10,000 acres to the field. The field is now drilled to a density of one well to 6½ acres, which is certainly more wells than necessary for economic production of the field. The close spacing of wells is due mostly to the type of proration, which is per well allowable based on a potential test, and does not take acreage into consideration, and also to the numerous small acreage tracts such as town lots and excess strips. The field now has 19,519 producing wells. The allowable production for the field during 1935 was 161,118,659 bbl.; estimated production, including illegal or "hot oil," was 174,200,150. The illegal production of oil gradually decreased throughout the year, until an estimated low was reached of 20,500 bbl. daily during the months of November and December. The price of oil remained at $1.00 per barrel throughout the year. As stated, about 10,000 acres were added to the field during the year, making a total of 128,000 productive acres. There is a possibility that

Jan 1, 1936

By C. G. Dunn, P. K. Koh

TWO recent review papers have considered the origin of primary and secondary recrystalliza-tion textures from the point of view of oriented nucleation and oriented growth theories."' Both theories require nuclei for primary recrystallization but provide no unequivocal answer to the question of what nuclei are. The answer to the same question regarding secondary recrystallization, however, often is that nuclei are certain primary recrystallization grains or primaries. The two theories differ, however, in specifying what the certain primaries are. In support of the oriented growth theory Beck and Hua originally stated "It may be assumed that in a re-crystallized material, even with a strong texture, there always are present some grains of practically any orientation. These may serve as nuclei for the coarse grains, provided that conditions are favorable for their growth." In commenting on this statement one would say that there are two restricting conditions: namely, that 1) the certain primaries (nuclei) are large enough to grow, and 2) their boundaries have high mobility. More recently Beck2 has con-

Jan 1, 1958

By A. Lubinski, C. R. Stewart, K. A. Blenkarn

Storage porosity has been considered one of the important pore geometry characteristics of heterogeneous-porosity limestones. Storage pores are only containers for fluids, in contrast to flow channel pores which both contain fluids and provide continuity for fluid flow. The concept of another geometry characteristic, "poro-striction", is presented as a second pertinent variable in describing limestone pore space. In simple terms, poro-striction is a measure of the flow resistance between storage and flow channel pores. Alternating-flow core-testing theory provides flow relationships which can be used to divide the pore space of heterogeneous-porosity media into flow channel and storage pores and to measure the "porostriction" of the latter. Experimental application of this theory to naturally occurring heterogeneous limestones shows that "porostriction" and the ratio of storage to flow channel pores can be estimated. Porostriction and porosity ratio are microscopic characteristics which should influence oil-recovery efficiencies during certain types of displacement processes. A knowledge of pore geometry should be valuable in designing or selecting the most effective oil-recovery process for heterogeneous limestones containing storage porosity. INTRODUCTION The primary and secondary recovery of oil from limestone (carbonate) reservoirs has been and will continue to be a major source of the world's supply of petroleum. Oil recovery from this type of formation is strongly influenced by the size, shape and arrangement of the pore spaces which hold the formation fluids. Therefore, it is expected that better knowledge of pore geometry would lead to design of more effective recovery processes. The concept of storage and flow channel pores has been presented as an important characteristic of limestone porosity.1 In this concept, storage pores are only containers for fluids, whereas flow channel pores are those pores which both contain and transmit the fluids. The work reported herein involves the concept of an additional pore characteristic called "porostriction". This characteristic can be visualized as the flow resistance between the storage and flow channel pores. This resistance is an important pore geometry characteristic because it determines how easily gas and oil can replenish fluids removed from the flow channel pores. Fatt and co-workers at the U. of California have studied the effect of storage porosity and a factor similar to porostriction on transient-flow response of models of porous media during a pressure build-up or drawdown test.55 These models consisted of porous sandstone cores with artificially simulated storage pores. It is the purpose of this paper to describe tests which permit the storage porosity and porostriction of actual reservoir core samples to be estimated. The tests used for this purpose involved not transient tests but, rather, an alternating-flow technique in which pressure and flow are varied according to a sine-wave relationship. This technique may offer advantages over transient methods. THE POROSTRICTION CONCEPT Before discussing alternating-flow (A.F.) tests in core samples, it is necessary to define the porostriction parameter. For this purpose attention is focused upon an elemental volume v representative of a porous medium having both flow channel pores and restricted-access storage pores. For such an elemental volume, it is considered that the storage porosity is combined to form a single pore and that the access into the storage porosity may be represented by a single capillary tube connecting the single pore to the flow channels of the elemental volume. Let the radius of the capillary tube be designated as Rc and its length as L,. When fluid flows into or out of the pore, the following equation (Poiseuille's law) relates flow rate q to pressure drop p, and the physical characteristics of the tube and the fluid of viscosity jx.

By D. R. Hay, E. Scala

Electrotransport has been superimposed on the rate-limiling- step in zone refining which is the impurity diffusion through the liquid at the solid/liquid interface. The efficiency of zone refining is increased and relative resistivity ratios (P300°k/P4 2°K) he increased by 50 pel in tungsten for a given number of posses using- the electrotransport field-aided method. The effiect of zotze refining in the presence of an electric field on the relative resistivity ratio is examined as a function of its intensity and polarity. THE effect of electrodiffusion on the effective distribution coefficient of zone refining has been discussed by Pfann and Wagner.' Control of the distribution coefficient in zone refining is of twofold interest. A distribution coefficient of unity can be increased or decreased, making possible the transfer of some previously inseparable solutes. The general efficiency of zone refining can also be increased. In the conventional zone-refining process impurities are removed by their retention in the molten zone and subsequent deposition at the end of the rod after a complete passage of the zone. In higher-melting-point systems a second mechanism may also operate, the volatilization of impurities from the molten zone. It has been suggested by schadler2 that, in refractory metals, vacuum distillation plays the predominant role in purification. In Koo's results,3 the resistivity ratio decreased beyond a zone-refined length of 6 in. from the starting end, indicating that some purification does in fact occur by true zone-refining action. Hay and scala4 showed that the degree of purity as measured by the relative resistivity ratio method depends on the square root of time in the molten zone (number of passes) and thus appears to be limited by diffusion in the boundary layer at the solidifying interface assuming good mixing in the body of the molten zone where a linear rate would prevail. The final concentration of impurities in electron-beam floating-zone purification depends very much on the operating conditions and results obtained by various investigators2,3,5 are difficult to correlate. The diameter of the starting material, operating vacuum, and rate of traverse are among the factors to be considered. There are, nevertheless, some general observations to be obtained from the literature. Lawley5 reviewed the literature up to 1962 and concluded that the major contaminants generally remaining in tungsten after electron-beam zone refining are molybdenum and carbon. Molybdenum due to its high melting point and distribution coefficient of nearly unity would be expected to be difficult to remove by either volatilization or zone refining. Carbon is not only a common contaminant in vacuum systems, but is also very difficult to remove by conventional vacuum melting. even with vacuums of 10-7 mm Hg. For each of those impurities removed by zone refining the equation of Pfann and Wagner may be applied: It relates the effective distribution coefficient k to a superimposed driving force which accelerates the solute away from the interface with a terminal velocity L" and to the more conventional zone-refining parameters; v = rate of traverse, t = thickness of the diffusion layer at the solidifying interface, D = diffusivity of the solute in the molten zone, and ko = equilibrium distribution coefficient of the impurity.

Jan 1, 1965

By C. E. Coleman, D. Hardie, A. E. Wraith

A photoguaplric method of measuring crack velocities has been applied to an examilzation of- the effect of hydrogen on the impact properties of zirconium. Results indicate that the crack in hydrided zirconit travels at about 26 m per sec whereas that in the uacuum -annealed is dependent on the speed of the hammer. RECENT work on the effect of hydrogen on zirconium reveals that when hydrided zirconium is tested in slow bending the crack producing failure can be unstable. The mode of fracture seems to involve the crack linking up broken hydrides by a ductile mechanism in the zirconium matrix.2" In order to compare the fracture of zirconium with that of other metals which show unstable crack propagation, notably steel, the rate of the crack spread must be known. As the methods previously used for measuring crack growth are either unsuitable for the present work5-'' or very costly," a simple technique has been devised in which the maximum crack velocity is derived from a series of crack position-time measurements. EXPERIMENTAL PROCEDURE The experimental arrangement is shown schematically in Fig. 1. The flash unit12 was triggered when the Charpy hammer touched the specimen and the 6-psec flash of the lamp delayed by a preselected time interval in the range 100psec to 10 msec. The camera was left on open shutter during the test. From direct measurement on a calibrated photographic print, Fig. 2, the position of the crack and the specimen was found at a known time after impact and, from a series of such tests using an appropriate range of flash-delay times, the crack velocity was estimated. Preliminary experiments were carried out on mild steel above and below its transition temperature. Vacuum-annealed zirconium, and zirconium hydrided to 100 ppm H were then tested at 20" and 150°C. For comparison, Zr-2.6 pct Nb alloy (in the 0 + transformed /3 condition), vacuum-annealed or hydrided to 100 ppm H, was tested at 20 C. The chemical analyses of these materials are given in Table I. For the high-temperature tests a fine chromel-alumel thermocouple was spot-welded onto each specimen close to the notch. The test piece was heated up to 200°C to allow enough time for preparing the apparatus while the specimen cooled to the testing tem- perature. It was assumed that the specimen cooled uniformly. The accuracy of the flash-delay time was better than i2 pct i 5 psec. The crack length was taken as its maximum distance traveled normal to the length axis of the specimen. Errors in these measurements arise as a result of the uncertainty in the location of the crack tip and the difficulty in defining the exact position of the crack starting point. The latter was due to the bonding and large amounts of deformation at the hammer contact point, especially in the vacuum-annealed specimens tested at 150°C. The maximum error in the measurements was however estimated to be about 5 pct. DISCUSSION OF RESULTS From the trial experiments using mild steel above its transition temperature it can be seen from the plot of crack length against time after impact, Fig. 3. that a reasonable estimate of the maximum crack velocity at the surface of the specimen may be made. Other features of note are the initiation time before the crack is first seen and the slowing down period

Jan 1, 1967

By F. Louis Grammer

The following study of flue-dirt and the influences controlling it may be interesting to many. It is published because it represents observations at about thirty furnaces at different times. It may assist in giving an impetus to the making of similar observations elsewhere. Until ten years ago, the metallic waste in furnace-gases was not considered a problem of pressing urgency in iron metallurgy—certainly not in the blastfurnace end of it. Many plants at present ignore, or pay but little attention to, top-pressures. Prior to the introduction of Mesabi ore, the losses in escaping gases, if considered at all, were regarded as thermal losses, or losses of fuel (except by those interested in lead, zinc, silver, etc.). In a high-priced material like ferro-manganese, such losses were, indeed, considered important. But the behavior of the Mesabi ores, corning, as they did, in practically inexhaustible quantities, could not be disregarded by the furnaceman. These ores came to stay. The tables appended below have purposely been altered to disguise the plant, the company and the ores used. The comparative values are maintained. In these tables, the influencing elements and conditions which are constant, or practically so, namely, size of furnace, quantity of wind, fuel used, etc., are not mentioned. The figures represent observations consistently followed up for a long period. The weights of flue-dirt were obtained from cars on which no other dirt was thrown. The analyses and calculations are based on the best of sampling. The effects of slips are excluded. Slips should not occur at well-regulated or properly-constructed furnaces, excepting under unusual and rare conditions. Allowances are made for moisture, scrap charged and silicon in the metal. The cutting effect of Mesabi

Jan 1, 1904

By Paul C. Merritt

For more than 100 years, British Columbia has been considered a mountainous mining province, rich with potential but relatively poor in actual production. Times have changed. Today, Japanese interests and money have altered the difficult, if not once impossible, economic conditions and market factors which until recently precluded any great growth of the British Columbia mineral industry. The mining boom now underway in British Columbia has carried the total value of mineral production in the Province to a record height in 1962 as it rang up a 27% increase over that of 1961. Breaking the $200 million barrier for the first time, total value of British Columbia's mineral output reached $229- 276,385. Of this amount, metals accounted for 70%; industrial minerals, 6 %; structural materials, 9 %; and fuels, 15%. The substantial increase is attributed to the record production of copper, iron, asbestos, natural gas and petroleum, in addition to the continuing high production rate and favorable prices of other mineral commodities.

Jan 12, 1963

Capital, as represented by mineral resources, is being exhausted rapidly without possibility of identical replacement. The public must be discouraged from thinking-why worry about the bank balance so long as there are plenty of blank checks? Instead of each man, woman, and child being owners of a mineral capital of $89,000 as former Secretary Ickes once stated, they are really the guardians of a mineral reserve which, when harvested, cannot be reproduced. The proper use of this material is the basis of modern civilization and military power. The best American institutions cannot be maintained or transmitted to our children unless this trust is guarded. It is unfortunate that more attention has not been focused on the fact that this country is headed for a have-not status in the family of great nations if some- thing is not done to preserve its mineral heritage. It is the privilege of the United States now to champion and implement democracy because it is industrialized and can get at its raw materials. A high price is being paid every day in mineral depletion for the privilege. No one can eat his cake and have it too. The United States still must face world-wide economic competition and, perhaps, World War III. In the final analysis all wealth comes from the ground, whether plant, animal, or mineral. Value is in-

Jan 1, 1950

By F. R. Brotzen, D. L. Davidson

ALTHOUGH much effort has been devoted to the problem, the nature of plastic flow in bcc metals is still not fully understood. Some of the difficulties encountered stem from the scarcity of information on orientation effects and the uncertainty as to the glide system in these metals. In an attempt to provide some of this information, the present investigation was carried out, using zone-refined molybdenum single crystals deformed in tension and in direct shear. Considerable evidence exists to indicate that the primary slip system for molybdenum is (110) <111>.1,2 Figs. 1 and 2 indicate that this is, indeed, the case for direct shear at room temperature (see Ref. 3 for a description of the shear-testing equipment and procedure). Moreover, from Fig. 2, the shear stress on the (123) is lower than that on the (112). This would be the case if, as has been suggested,4,5 slip on these two planes is in reality com-

Jan 1, 1965

By Harrison Schmitt

IN the practice of ore finding the geologist is continually confronted with the question of oreshoot extension, so that the general problem seems worthy of systematic investigation. This problem appears when the reserves are estimated and when the advisability of deepening the shaft comes up. Moreover, there is need for lower development cost to keep pace with cost reductions in other departments, or even to offset a rising cost of ore finding or ore following. This can be gained by close geologic control of the development; and much of the geology involved is that bearing on the downward, upward, and horizontal extensions of shoots. Furthermore, the purchase of a mine or prospect often depends directly on the question of shoot extension; because it is seldom that the ore is fully developed and the purchase price is almost invariably based largely on "possible" and geologically prospective ore. Most current methods for estimating "possible" and the more nebulous classes of ore are crude and indecisive. In the following pages the extension of oreshoots is the major theme, although the more basic subject, the general art of ore finding, is given some space.

Jan 1, 1929

By C. D. Hunter, I. B. Browning, N. W. Shiarella

During the year 1936 improvement in the oil industry in Kentucky continued at about the same rate as shown by that of the year 1935 over the year 1934. The development of several new pools in western Kentucky and the increase in the application of repressuring methods to the old fields of eastern and to a lesser extent of western Kentucky increased the total production to 5,481,227 bbl., as compared to 5,175,054 produced in 1935. The principle sources of this increased production are the Livermore field and the new Bates Knob field in McLean County, in western Kentucky, and the result of repressuring operations in the " Corniferous" pools of Lee, Powell, Wolfe, Morgan and Estill Counties and the "Weir" sand (of Mississippian age) fields of Magoffin, Lawrence and Johnson Counties in northeastern Kentucky. The last named fields have a producing sand especially adaptable to these methods. Drilling No new fields were opened in eastern Kentucky during the year. All new drilling was codned to pressure wells and new oil wells to complete patterns around the intake wells. Owing to the relatively low "initial" or flush production of the wells in this section—even though the ultimate recovery per acre is as large—higher prices for crude will have to prevail before extensive search for new fields is begun; as in northwestern Kentucky, where active exploratory work has been carried on as in the several preceding years, resulting in numerous new and prolific, although comparatively small fields. In this section approximately 500 new oil wells drilled in the Owensboro field, embracing several pools in Ohio, Hancock, Daviess, McLean, Henderson, Webster and Nuhlenberg Counties in the northwestern part of the state. The total oil production for this field during 1936 exceeded by many thousand barrels the 2,821,722 bbl. produced in 1935. In these fields the producing sands range from the middle Missis-

Jan 1, 1937