Search Documents

By Gustave E. Behr

The peculiar and changing conditions of a wartime market and the necessary governmental restrictions have resulted in an accumulation of a large amount of certain secondary metals in the tin-lead alloy class. With certain of these metals this accumulation has reached such proportions that it has been proposed that government agencies finance the creation of stockpiles of these secondaries just as stockpiles of primary metals have been created. The purpose of such financing would be to keep the secondary metal dealers engaged in collecting these metals, which they might

Jan 1, 1943

By Donald Barton

Geophysical methods of prospecting taken as a whole do not seem to offer much promise to a young man planning to enter them in the future. They have come to stay, to be sure, and they will continue in at least moderate use for a long time. Domestic use of those methods presumably is at a maximum at the present time. Geophysical pros-pecting is expensive; the effects of the law of diminishing returns in efficiency in finding prospects can already, be recognized. Small oil companies, independent oil operators, and royalty buyers have been doing much geophysical work. But in face of the increasing costs of discovery of prospects and in face of the probably decreasing favorability of the prospects discovered, I expect to see a sharp drop in their use of geo-physics within the next 10 years. The major oil companies and the larger small oil companies will continue to use geophysics indefinitely, but it seems doubtful whether the very extensive domestic campaigns of a few companies will be maintained for many years, certainly not for 10 years. The use of the geophysical methods in foreign countries has not yet reached its peak, and probaby will continue to increase for several years. That peak level of activity will probably be held for 10 years, although the site of maximum activity will shift from country to country; by the end of 25 years from now, I should expect the foreign use of the methods to have leveled off to one-fourth to one-half the peak level. Foreign service in geophysics does not seem to offer an attractive career, except for men of exceptional disposition. Young men just out of college, who are willing and who can afford to spend three or four years having a fling at adventure before settling down, will find it attractive, but when their tour of foreign service is over, they probably will have harder work finding a job than when they were seniors, and their foreign experience will count for little, except for further foreign service. A few men, mainly the higher men, will have headquarters at civilized or semi-civilized cities and towns or at permanent oil-company towns, and can

Jan 1, 1938

By Robert L. Schuster, James A. Doolittle, Ronald L. Sack

The effect of the height of a retaining-wall-supported berm on the slope stability of an idealized mine-tailings dam was investigated. The material in the dam was idealized as a two-layered system with the phreatic surface delineating the boundary between the layers. In each layer the tailings were assumed to be homogeneous and isotropic. The effect of variation in height of the berm was examined for tailings dams with three different, commonly occurring slopes. The stresses and displacements were obtained using the finite element method. An incremental analysis technique was employed to simulate sequential construction of both the tailings dam and the retaining-wall-supported berm. A one-dimensional element was used to represent all interfaces and discontinuities in the finite element model. Assuming a hyperbolic model, the nonlinear stress-strain relationship for the tailings was approximated using the method of successive increments. The stresses obtained in the finite element analyses were used in conventional slope stability analyses assuming circular failure surfaces. The results of the study show that the use of a retaining-wall-supported berm is an effective means of improving the stability of a tailings dam. This increased stability is greater for dams with steeper slopes. In addition, the increase in factor of safety is particularly notable for berm heights less than 25% of the height of the dam.

Jan 1, 1975

By W. A. Ver Wiebe

The year 1940 was singularly unmarked by sensational developments in Kansas. Routine operations were carried on in a systematic, orderly fashion and the efforts of oil producers were concentrated on extending known fields. In Kansas an arbitrary yardstick for wildcats has been set up. A well drilled mile or more from a known pool or well is now considered a wildcat. A "rank wildcat" is one that is drilled at least 2 miles from any known producer. During 1940, rank wildcats resulted in the completion of 116 test wells, among which 16 were successful in finding new oil pools and the remaining I00 were dry holes. The ratio of successful wells to dry holes, therefore, was approximately I:6. During the year, 1890 wells were completed in eastern and western Kansas. This figure is somewhat lower than that given in several trade journals, because it does not include wells that were deepened or wells that were recompleted in a different geological horizon. About three fourths of these (1423) were completed as commercial oil wells (I220 in western and 203 in eastern Kansas). The commercial gas wells completed number 58 of which 10 are in eastern Kansas and 48 in western Kansas. Of the remzining completions 147 are dry holes in eastern and 262 are dry holes in western Kansas. Based on daily potential capacity, the new discoveries of the year account for a cumulative initial production of 46,000 bbl. in eastern and 2,128,000 bbl. in western Kansas. The state of Kansas attained a new peak in production, with the total of 66,245,000 bbl. for the year 1940, the number of contributing wells being 20,779. Thus the increase over 1939, when about 58 million barrels was produced, is considerable. The previous peak occurred in 1937, when 70,761,000 bbl. was marketed. In another still earlier peak, in 1917, slightly more than 45,000,000 bbl. was produced and sold. The production of gas probably reached a new peak also during 1940, with its total of 85 1/2 billion cubic feet. Between the peak of the year 1908, when over 80 billion cubic feet was produced, and that of 1940, the production dropped to a low point of 16 billion cubic feet in the year 1921. The number of test wells drilled was larger than in 1939; that is, 1890 compared with 1458. The first peak was reached in 1904, when 2782 wells were drilled. The number dropped off rapidly, to 368 three years later, but rose to the second and highest peak in 1918, when 4671 test wells were completed. In the period between 1904 and 1912 more gas wells were completed than oil wells. Between the high peak of completions in 1918 and somewhat lower peak of 1937, the low point was reached during 1931, with the completion of only 470 test wells. In the number of new pools discovered, Kansas again ranks high among the states. The exact number depends somewhat upon the interpretation of a "new" area— whether it should be called a new pool or a long extension of an old pool. Unfortunately, the matter of securing the right kind of production allowable also enters into this question. Often the decision regarding a new pool cannot be made until other wells

Jan 1, 1941

By W. A. Ver Wiebe

The year 1940 was singularly unmarked by sensational developments in Kansas. Routine operations were carried on in a systematic, orderly fashion and the efforts of oil producers were concentrated on extending known fields. In Kansas an arbitrary yardstick for wildcats has been set up. A well drilled mile or more from a known pool or well is now considered a wildcat. A "rank wildcat" is one that is drilled at least 2 miles from any known producer. During 1940, rank wildcats resulted in the completion of 116 test wells, among which 16 were successful in finding new oil pools and the remaining I00 were dry holes. The ratio of successful wells to dry holes, therefore, was approximately I:6. During the year, 1890 wells were completed in eastern and western Kansas. This figure is somewhat lower than that given in several trade journals, because it does not include wells that were deepened or wells that were recompleted in a different geological horizon. About three fourths of these (1423) were completed as commercial oil wells (I220 in western and 203 in eastern Kansas). The commercial gas wells completed number 58 of which 10 are in eastern Kansas and 48 in western Kansas. Of the remzining completions 147 are dry holes in eastern and 262 are dry holes in western Kansas. Based on daily potential capacity, the new discoveries of the year account for a cumulative initial production of 46,000 bbl. in eastern and 2,128,000 bbl. in western Kansas. The state of Kansas attained a new peak in production, with the total of 66,245,000 bbl. for the year 1940, the number of contributing wells being 20,779. Thus the increase over 1939, when about 58 million barrels was produced, is considerable. The previous peak occurred in 1937, when 70,761,000 bbl. was marketed. In another still earlier peak, in 1917, slightly more than 45,000,000 bbl. was produced and sold. The production of gas probably reached a new peak also during 1940, with its total of 85 1/2 billion cubic feet. Between the peak of the year 1908, when over 80 billion cubic feet was produced, and that of 1940, the production dropped to a low point of 16 billion cubic feet in the year 1921. The number of test wells drilled was larger than in 1939; that is, 1890 compared with 1458. The first peak was reached in 1904, when 2782 wells were drilled. The number dropped off rapidly, to 368 three years later, but rose to the second and highest peak in 1918, when 4671 test wells were completed. In the period between 1904 and 1912 more gas wells were completed than oil wells. Between the high peak of completions in 1918 and somewhat lower peak of 1937, the low point was reached during 1931, with the completion of only 470 test wells. In the number of new pools discovered, Kansas again ranks high among the states. The exact number depends somewhat upon the interpretation of a "new" area— whether it should be called a new pool or a long extension of an old pool. Unfortunately, the matter of securing the right kind of production allowable also enters into this question. Often the decision regarding a new pool cannot be made until other wells

Jan 1, 1941

By D. N. Dietz

A method for determining average reservoir pressure is presented, which is simpler to apply than that devised by Matthews. Brons and Hazebroek. For bounded reservoirs, identical results are obtained if stabilized-flow conditions prevail. The present method yields inferior results in the transient state. The method can, with a slight modification, also be used for water-drive reservoirs. INTRODUCTION In the method proposed by Matthews, Brons and Haze-broek' for determining average reservoir pressure in a multi-well reservoir, the cumulative production (the production time of each well) enters twice: once when the buildup is plotted against In (t + t)/At to arrive at p*, and a second time when the correction, p*-p is determined with one of the several formulas for differently shaped drainage areas. Once a steady state has been attained, however, the previous production history should be immaterial. The same pressure distribution could have been arrived at after different cumulative productions of the individual wells. In principle, therefore, it should be possible to determine average pressures without referring to cumulative productions. In the following paragraphs an expression is presented for the difference between the pressure in a producing well and the average pressure of its drainage area. Then the build-up time needed to overcome this difference is indicated. CASE OF A CIRCULAR DRAINAGE AREA AND A CENTRAL WELL PRESSURE DISTRIBUTION BEFORE SHUT-IN The general differential equation of radial flow (see Muskat, Eq. 10.2) may be written In the steady state, the rate of production of the well is equal to the rate of expansion of the fluid contained in the the drainage area; thus

Jan 1, 1966

By E. T. Turkdogan, P. Grieveson

The self-diffusion coefficient of oxygen in a liquid silicate slag containing 40 pct SiO2, 40 pct CaO, and 20 pct Al2O3, was determined using the capillary eff;usion technique. Two stable isotopes of oxygen (O17 and O18) were used as tracers. After each diffision run, the slags were reduced with graphite, the evolved carbon monoxide collected and converted into CO,. The oxygen isotope concentrations were obtazned by measuring the (CO2)45/(CO2)44 and the (CO2)46/(CO2) ratios of the gas. It was found that for O17 Exchange of oxygen between neighboring silicate anions, possibly accompanied by the rotation of these complexes, is a probable diffusion mechanism. The exchange of oxygen atoms between holes in the silicate "lattice" may also be postulated. A full understanding of the properties of slags is unlikely unless the structural details are clearly established. Thus properties such as surface tension, viscosity, expansivity, electrical conductivity, ionic mobility, density, compressibility, and so forth, have been studied. Of importance also are the self-diffusion coefficients and the energies of activation for diffusion of the component ions. The self-diffusion coefficients of calcium, 1-3silicon,, sulfur,4 and aluminumS in a ternary silicate slag have been determined with the aid of radio-isotopes. The self-diffusion coefficient of oxygen in such a slag was investigated in the course of the work reported here.

Jan 1, 1962

By Walter W. Lilly, Issa S. Oweis

Application of rock engineering in geotechnial consulting practice considered herein is in areas of: (a) bedrock verification for foundation support, (b) bearing capacity and settlements, and (c) excavations. A routine geotechnical investigation usually provides data on depth to rock, rock classification, and rock quality. In cases of rock outcrop, such outcrops are mapped for geologic structures and rock mass description. In addition, the regional geology and the general aspects of the groundwater regime are usually known from either published literature or previous experience. The predominant technique for ground and site investigation are usually drilling and geologic reconnaissance. Other techniques involving seismic and geophysical soundings, borehole camera, and oriented cores are used by by no means routine. Performing laboratory strength and compressibility tests is often made to be considered as routine. The use of the point load test is gaining increasing use in the United States and would, perhaps, become a routine field or laboratory test due to its simplicity and, more importantly, its relatively low cost. The purpose of this paper is to describe cases where mostly routine investigation and testing were used to arrive at engineering decisions. Bearing Capacity and Settlements The allowable bearing values for foundation support on rock is usually dictated by local building codes which presumably should reflect local experience. The interpretation of the code, however, can present a problem, especially if the interpretation is made by a designer under the delusion of knowledge in rock engineering. For

Jan 1, 1982

Shoemaker: We've all heard a lot about epoxy liner backings. This brings up the question-do zinc furnaces still have a place in a new plant? Meaders: I would, you must understand, be prejudiced in this question because we introduced epoxy backing into the industry. Naturally, we wouldn't have done so if we didn't think it should be done. With that background maybe I could give a little more information on this particular subject than some of the others, because we now have been in this business for some three or four years.

Jan 11, 1967

By M. Paulus

It is known that multicomponent powders are mostly nonhomogeneous. This paper investigates the effects of nonhomogeneity of composition and grain size on the melting point and the sinterability of compact taking into account homogenization mass transport and the length of the diffusion path in solid state sintering, and the kinetics of liquid phase formation in liquid phase sintering. After a discussion on the ideal characteristics of a powder for sintering and low temperature reaction, the main conventional processes are compared. Finally we develop the freeze-drying technique and demonstrate the capabilities and the limits of the process by some examples, mainly in the ceramics field.

Jan 1, 1980

By W. C. Krumbein

GEOLOGICAL problems are approached from a geometrical (space relations) viewpoint, a kinematical (time sequence) viewpoint, or a dynamical viewpoint. The first two require sound training in conventional geology and in field methods. The third approach requires a solid foundation of chemistry, physics, and mathematics. Modern training for geologists should include close integration of basic sciences with geological principles. INTRODUCTION Our knowledge of the earth has increased tremendously during the last half century. We know more about its surface configuration, the distribution of its natural resources, the procession of living forms that inhabited it in the past, the chemical composition of its oceans, the areal distribution of its surface rocks, the movements of its atmosphere, and so on. Not only do we know more facts about the earth, but we have a better understanding of the processes that take place on and within it, such as the nature of earthquakes, the thermodynamics of the atmosphere, the chemical equilibria involved in the formation of igneous rocks, the mechanics of stream flow, the dynamics of the earth's origin, and so on. Many sciences contributed to the sum total of this knowledge, including such established disciplines as geology, geography, physics, chemistry, astronomy, biology. Out of this accumulation of new knowledge grew also a group of new sciences, such as seismology, oceanography, meteorology, volcanology, hydrology. Collectively these latter are known as the geophysical and geochemical sciences, and to a large extent they began as branches of geology. Until the turn of the century, for example, the study of earthquakes (seismology) was a part of geology, although as early as 1846 Mallet, a physicist, had suggested that the subject could be investigated by elastic-wave theory. Comparatively little progress was made along these lines until the seismograph was developed near the turn of the century; since then, additional earthquake data have accumulated rapidly, but more important, the interpretation of these data essentially has kept pace with their accumulation. In similar fashion, meteorology, was generally considered a branch of geology as recently as one or two decades ago. Considerable progress had been made in such aspects as weather forecasting, but the science dates its recent rapid rise from the year 1911, when Bjerknes first applied the principles of dynamics to the analysis of air masses. The rapid development of such disciplines as oceanography, volcanology and hydrology was due in part to the application of principles of chemical equilibrium, of dynamics, and of thermodynamics to earth problems, by men who were essentially physicists or chemists by training. The last half century, therefore, and particularly the last two decades, saw the influx of numerous chemists and physicists into the realm of the earth sciences. In the meantime the main body of geology itself showed a marked growth, and

Jan 1, 1941

By A. Beeby Thompson

FOR more than 2500 years, natural gas issues in the Surakhany district of the Apsheron peninsula were the object of pilgrimages by fire worshippers and Hindoos from Burma and India. Even as late as 1890, Hindoo priests conducted ceremonies in a temple at Surakhany, which probably replaced a more ancient one; but later, the visits of the pilgrims were prohibited in order to check the spread of Asiatic diseases in that region. For centuries, limited supplies of oil have been abstracted from shallow excavations in the Caspian oil belt and dispatched into the interior of Asia and elsewhere for medicinal and industrial purposes. Statistics show a yield of 37,400 bbl. in 1863, but only since 1869 has there been serious development; in that year the yield was 203,000 bbl. At that time, hand digging was supplanted by drilling, and the enormous wells that resulted from tapping sources hitherto beyond the reach of operators completely demoralized the industry for a time, owing to inadequate outlets for the products. The early activities in this area were greatly hindered by annoying taxation, monopolies, imperial land grants, etc., but when these were revoked or adjusted, in 1877, the industry sprang into prominence and, between 1898 and 1901, the Baku fields produced practically one-half of the world's supply of oil. Within a few miles of Baku lie the two richest oil fields in the world; viz., the Balakhany-Saboontchy-Romany and the Bibi-Eibat, the latter constituting almost a suburb of the city. For many years the gasoline obtained in the refineries of the Baku area was burned in pits, being considered an undesirable product, and until 1870 the residue also was destroyed, its value as a fuel not being recognized. Kerosene was the main product sought by the refiners. It was shipped across the Caspian Sea and up the Volga to the industrial centers of Russia. Only on the completion of the Baku-Batoum railway did the Baku oil fields secure

Jan 8, 1920

By H. Herbert Hughes

In the years following World War II, L. de Roll S.A., Zurich, Switzerland, perfected its vertical kiln. De Roll first became interested in cement-manufacturing equipment in 1947, not only kilns but also the crushing, grinding, and handling equipment required for a complete cement plant. The parent company, Louis de Roll Iron Works, S.A., Gerlafingen, Switzerland, was founded in 1804. In its six plants, and with its associated companies, de Roll manufactures and installs equipment for a wide variety of industries-chemical and metallurgical operations, fats and oils plants, and municipal refuse incinerators and sewage disposal installations. Vertical shaft kilns, of course, are as old as Portland cement itself. Their fuel economy has long been recognized, particularly in Europe where fuel costs are high. But the disadvantages of old-type shaft kilns have been the lack of consistent quality of the clinker, the small capacity, and the relatively high labor costs.

Dec 1, 1956

By Paul L. Burkhart

THOUGH at an earlier period brief studies had been made by the Lehigh Navigation Coal Company Inc., it was not until 1924 that J. B. Warriner, then general manager, called for a comprehensive study of timber treatment, treating solutions, and related operations. Because of the impossibility of procuring accurate costs and other pertinent treating data, the American Wood Preserving Co. agreed to treat a car of mine timber at the Port Reading plant of the Reading Railroad. Fig. I shows the treating data collected at the treating plant on this timber, which was installed in two of the Lehigh mines in 1925. [ ] In the latter part of 1925, a survey of the tunnels and gangways of the company's Panther Valley mines was made to determine the proportion of gangways or tunnels timbered, cause of timber failures, approximate life of the average wood set and the approximate percentage of treated timber that it would be profitable for the company to use. Results of this survey appear in Table I. Because of the high percentage of timber that gave evidence of failure by rot, as noted in Table I, and a further study of the life of the sections where timbering was necessary, it was deemed advisable to fill 25 per cent of the yearly gangway timber requirement with treated timber. QUANTITIES AND TREATMENTS OF TREATED TIMBER PURCHASED In the early days of the program, none of the large treating companies would accept orders for small quantities of treated timber and the company was compelled to state the quantity of timber it would require at each operation in each month of the year. Table 2 is an example of the tabulation given to the various treating companies to assist them in making a yearly bid on the minimum quantity of timber required by the company during the year 1931. A bill of timber was calculated for each car, the weight of which would be between the minimum and maximum weight permitted for railroad-car loading. The treating company was paid for timber upon delivery at the operation specified. As extra cars of timber were required, they were ordered from the treating company, and payment was required on their receipt, on the basis of the piece or tonnage

Jan 1, 1942

By H. K. Shearer

North Louisiana (including all townships north of the Louisiana base line) had a year of normal development in 1940, marked by the discovery of two shallow oil fields producing from the Wilcox formation in La Salle Parish and a large increase in drilling in the old Caddo shallow field. This renewal of shallow drilling activity led to a somewhat unexpected increase in the number of wells drilled, although the total footage and average depth continued to decline, as in several preceding years. Well completions and depth statistics for 1940, with previous years for coinparison, are as follows: Wildcat producers in 1940 include the discovery oil wells in the Olla and Nebo fields; also three gas wells in the vicinity oi the Olla field and a shallow gas well, which opened a new field or extension in the Greenwood area of Caddo Parish. This table illustrates the lack of important deep discoveries since 1937, in which year the Rodessa, Lisbon and Cotton Valley fields were being actively developed. Operators have been forced to return to the old type of shallow drilling, which necessarily means smaller producing wells. Oil production in 1940 was 24,381,760 bbl., a decrease of 867,880 bbl. from 1939, or 3.44 per cent. The newly discovered fields of La Salle Parish produced over a million barrels, and other increases worthy of note were at Cotton Valley, Caddo, Sligo and Sugar Creek. The greatest decrease was again at Rodessa, although this remains the principal producing field. Geological Names Revised Deep drilling during 1940 did not provide a great deal of new geological information. However, by agreement of a majority of the members of the Shreveport Geolog- ical Society, the names of some of the Lower Cretaceous formations have been revised in the interest of greater clarity and in order to make the descriptions agree better with the facts discovered in recent years. The geological section is discussed in detail and reasons for changes in nomenclature are stated in a recent publication by Ralph W. Imlay. Although not yet in universal use among field men, the new names are employed in this report and accompanying tables, as

Jan 1, 1941

By H. K. Shearer

North Louisiana (including all townships north of the Louisiana base line) had a year of normal development in 1940, marked by the discovery of two shallow oil fields producing from the Wilcox formation in La Salle Parish and a large increase in drilling in the old Caddo shallow field. This renewal of shallow drilling activity led to a somewhat unexpected increase in the number of wells drilled, although the total footage and average depth continued to decline, as in several preceding years. Well completions and depth statistics for 1940, with previous years for coinparison, are as follows: Wildcat producers in 1940 include the discovery oil wells in the Olla and Nebo fields; also three gas wells in the vicinity oi the Olla field and a shallow gas well, which opened a new field or extension in the Greenwood area of Caddo Parish. This table illustrates the lack of important deep discoveries since 1937, in which year the Rodessa, Lisbon and Cotton Valley fields were being actively developed. Operators have been forced to return to the old type of shallow drilling, which necessarily means smaller producing wells. Oil production in 1940 was 24,381,760 bbl., a decrease of 867,880 bbl. from 1939, or 3.44 per cent. The newly discovered fields of La Salle Parish produced over a million barrels, and other increases worthy of note were at Cotton Valley, Caddo, Sligo and Sugar Creek. The greatest decrease was again at Rodessa, although this remains the principal producing field. Geological Names Revised Deep drilling during 1940 did not provide a great deal of new geological information. However, by agreement of a majority of the members of the Shreveport Geolog- ical Society, the names of some of the Lower Cretaceous formations have been revised in the interest of greater clarity and in order to make the descriptions agree better with the facts discovered in recent years. The geological section is discussed in detail and reasons for changes in nomenclature are stated in a recent publication by Ralph W. Imlay. Although not yet in universal use among field men, the new names are employed in this report and accompanying tables, as

Jan 1, 1941

By K. E. Niermeyer, J. A. Bratt, B. A. Fahm, B. A. Kennedy

The instrumentation, monitoring, and prediction of a major slope failure at the Chuquicamata mine are described. In December 1967, preexisting tension cracks on the south end of the east wall of the mine began to open. Various forms of instru¬mentation were installed for continuous monitoring. These systems included tension crack stakes, crack extensometers, linear extensometers, tape and transit lines, sliding wire contacts, and a seismograph. From the information obtained, the failure date was accurately predicted some five weeks before failure, enabling the mine to reroute truck and rail access; hence, causing a minimal mine shutdown of 21/2 days and preventing any injuries to person or damage to equipment. The shape and form of the sliding mass are analyzed, as are possible modes of failure.

Jan 1, 1972

By W. C. Krumbein

GEOLOGICAL problems are approached from a geometrical (space relations) viewpoint, a kinematical (time sequence) viewpoint, or a dynamical viewpoint. The first two require sound training in conventional geology and in field methods. The third approach requires a solid foundation of chemistry, physics, and mathematics. Modern training for geologists should include close integration of basic sciences with geological principles. INTRODUCTION Our knowledge of the earth has increased tremendously during the last half century. We know more about its surface configuration, the distribution of its natural resources, the procession of living forms that inhabited it in the past, the chemical composition of its oceans, the areal distribution of its surface rocks, the movements of its atmosphere, and so on. Not only do we know more facts about the earth, but we have a better understanding of the processes that take place on and within it, such as the nature of earthquakes, the thermodynamics of the atmosphere, the chemical equilibria involved in the formation of igneous rocks, the mechanics of stream flow, the dynamics of the earth's origin, and so on. Many sciences contributed to the sum total of this knowledge, including such established disciplines as geology, geography, physics, chemistry, astronomy, biology. Out of this accumulation of new knowledge grew also a group of new sciences, such as seismology, oceanography, meteorology, volcanology, hydrology. Collectively these latter are known as the geophysical and geochemical sciences, and to a large extent they began as branches of geology. Until the turn of the century, for example, the study of earthquakes (seismology) was a part of geology, although as early as 1846 Mallet, a physicist, had suggested that the subject could be investigated by elastic-wave theory. Comparatively little progress was made along these lines until the seismograph was developed near the turn of the century; since then, additional earthquake data have accumulated rapidly, but more important, the interpretation of these data essentially has kept pace with their accumulation. In similar fashion, meteorology, was generally considered a branch of geology as recently as one or two decades ago. Considerable progress had been made in such aspects as weather forecasting, but the science dates its recent rapid rise from the year 1911, when Bjerknes first applied the principles of dynamics to the analysis of air masses. The rapid development of such disciplines as oceanography, volcanology and hydrology was due in part to the application of principles of chemical equilibrium, of dynamics, and of thermodynamics to earth problems, by men who were essentially physicists or chemists by training. The last half century, therefore, and particularly the last two decades, saw the influx of numerous chemists and physicists into the realm of the earth sciences. In the meantime the main body of geology itself showed a marked growth, and

Jan 1, 1941

By F. S. McNicholas

IN the first big blast at Climax, a "loop back" (three-wire system) was used (Fig. I), with the idea of securing a wiring system that would give to all series the same amount of current. Single-phase, 60-cycle, 13,800-volt [ ] power was furnished to the blasting transformers, each of which has a rated capacity of 600 amp. at 480 volts. Two blasting leads were taken from these transformers, giving a blasting current of single phase, 60 cycle, 480 volts, with an instantaneous capacity of more than 600 amp. The blasting switch was on the secondary leads from the transformers, to avoid lag in energizing them.

Jan 1, 1938

By B. L. Seegmiller

Horizontally stratified lithologies of certain open pit or strip mines create unique stability problems for mine operations. Such problems may result when specific lithologies, such as sandstone and shale, exist in final or long-term slopes. Slope instabilities may occur when a sandstone unit directly overlies a shale unit and ground water drains into the mine along the lithologic contact. In essence, the ground water erodes the underlying shales and undercuts the sandstone. Large sandstone blocks fail in a toppling mode and cause safety and cleanup problems. Use of rock reinforcement including chain link fencing, roof bolt mats, rock bolts, rock anchors, and shotcrete offers a possible solution to the problem.

Jan 1, 1985