Search Documents

By Beardsmore G. R

Geothermal gradients in the Gippsland Basin commonly exceed 35¦ C/km. Consequently models of thermal maturation may indicate exploration targets with an anomalous age/depth distribution. However regional geothermal models are constrained primarily by observations of surface heat flow. High geothermal gradients may simply reflect the presence of low conductivity coal beds within the basin. Heat flow data are not readily available for the Gippsland Basin. Normally special purpose drill holes are required to provide direct determinations of surface heat flow. These provide core samples for thermal conductivity and allow measurements of a stable geothermal gradient at least one year after drilling. Different indirect procedures are now required to provide estimates for the Gippsland Basin. Bottom hole temperatures can be used with suitable corrections to provide an indication of the regional geothermal gradient. However the corresponding thermal conductivities are more difficult to determine. Geophysical logs can be used to detect the major lithologies but detailed statistical analysis is required for numerical estimates. Complex mixing models are now suggested for geothermal surveys linking physical properties to variations in the mineralogy of each well. Allowing for low conductivity coal measures the data in the Gippsland Basin suggest values for heat flow consistent with regional trends in Australia. Interpretation is complicated by overprinting of transient thermal events with different time scales. Apart from the tectonics of basin evolution geothermal signatures may be complicated by regional ground water migration, the 'hot spot' trace associated with southward younging of Cainozoic volcanism, diagenesis, and basin refraction.

Jan 1, 1992

By R. H. Wightman, G. H. Adams

In order to secure good results in the prevention of accidents, it is generally recognized that the desire for such accomplishment, as well as the aggressive and constructive action to achieve it, must emanate from the Top Management and permeate successively down through the "Chart of Authority" to the workmen. Several years ago, with the above as a basis and with full support of the Top Management, the Mining Department started a program of selling the foremen and bosses the idea that safety could be achieved and that it was desired and required. Using psychology, persistence and numerous other methods, the foremen and bosses were finally impressed with the idea that "It can be done" and "It will be done." With this in mind, new ideas were brought forth by the foremen and bosses regarding the caving operation and the specific jobs in the operation. These new ideas were taken up in round-table discussions and resulted in certain changes in the undercutting method and the actual drawing of the blocks. These changes resulted in increasing fragmentation of the blocks which prevented the usual hang-up areas in the blocks. With the rock smaller in size and within reasonable reach from the tapping drifts, accidents were prevented in the tapping section. At the same time, an enforced campaign of housekeeping throughout the mine was undertaken with very beneficial results. The foremen and bosses then, in turn, educated and trained the workers themselves to become safety conscious. In so doing, a constant reminder was given on all jobs assigned that the job was to be done safely as well as efficiently. No man is assigned a job who is not qualified for the type of work required. Efficiency and safety go hand in hand. Safety Rules To supplement and aid this safety conscious attitude, certain safety rules applicable to our operation, a modified block caving system of mining limestone, in addition to the established state regulations, were put into effect and enforced. The specific rules referred to above and which will be mentioned below are in most cases simply a means of applying and complying with the very adequate "Mine Safety Orders" issued by the Industrial Accident Commission of the State of California. Some of the safety rules and policies are as follows: All men are required to wear safety

Jan 1, 1950

By S. Papanakli, Th. Rondoyanni, N. Sabatakakis, K. Kavoura, G. Tsiambaos

"A representative composite fault-related landslide of the Corinth Gulf graben named “Panagopoula” is reported that considered to be one of the most prone to slope instability sites along the main motorway and railway connecting Athens with the city of Patras. The presence of tectonically highly sheared and weathered geological formations, including Alpine basement (mainly flysch) contributes to the site instability, triggered/reactivated by seismic activity and heavy rainfalls. Although a series of remedial measures have been already constructed, the inclinometer readings during the last twenty years time period show a continuous very slow movement which indicates that the landslide is still ""active"". This fact has resulted to divert the axes of the new motorway and railway through twin tunnels which are under construction. INTRODUCTIONThe spatial and temporal evolution of landslides in the case of structurally complex slopes is lithologically and often structurally controlled while their type and frequency are mainly related to tectonic and lithological anisotropy (Baron et al. 2005; Hradecky et al. 2007). The triggering mechanisms mainly include: (a) excessive rainfall generating high pore pressure and (b) strong earthquakes resulting in dynamic loading conditions at the failure surface. Data such as past earthquakes or the precipitation records are useful to be gathered when a landslide model is examined since they could act as a landslide triggering mechanism. Recording of the movement through surface and inclinometer measurements as well as combination of the above information with historical records of failure could lead to a more accurate estimation of the location of the failure surface and understanding of the landslide mechanism.Slope instability in the southern segment of the Gulf of Corinth, Northern Peloponnesus, Greece, is ubiquitous and ranges from deep-seated bedrock failure to secondary earth flows in recent deposits. In this part of Greece, the periodically induced landslide events triggered by heavy rainfall, earthquake and anthropogenic activity are closely related to active fault tectonics. The Gulf of Corinth is considered as a typical example of a relatively simple asymmetric half-graben with major border faults to the south and a flexure of the northern shore. Panagopoula landslide is located along the trace of a WNW trending normal fault (dipping northwards) (Figure 1). The area is considered to be one of those most prone to slope instability along the E95 motorway and railway connecting Athens with the city of Patras."

Jan 1, 2015

By W. E. Glenn

The years immediately ahead-1961, 1962, 1963- will be critical years from every standpoint for the young engineer. In the next few years, he must learn to grow professionally. Most often, the rate and extent of this growth will be governed by his own initiative and perseverance. Habits and attitudes acquired during these early professional years relate very closely to, and even foreshadow, future accomplishments. The future goal of the young engineer is a moving target. It will change with professional growth, family requirements, changes in predominant interest, general economic and business conditions and geographic location. However ambitious and stead-fast in his goal he may be, the young engineer should not hesitate to adjust or change-for he really does not know initially what he is best fitted for and will not know until he has tried a number of things patiently and persistently.

Jan 1, 1961

A $5000 contract to explore for asbestos in Marinette County. Wis., has been entered into between the Government and the Star Mining Co. of Madison, Wis. The Government will contribute 90 pct or $4500 to the cost of the project. The United States presently produces about 8 pct of its asbestos requirements. "Sulphur stockpiles are at a minimum for national security arid must not be further reduced," was the warning given by L. M. Williams, Jr., president of Freeport Sulphur Co. He stated that although the long-range outlook is favorable , current sulphur production cannot meet the demand and as a result the United States faces a crisis in the coming months.

Jan 12, 1951

By Calvin C. Brown

A university is a place to build minds and develop leaders. It provides the tools necessary for the development of new ideas which come from the inquisitive mind and is one of the stepping stones to management responsibilities for the truly ambitious. However, it is not always a financially sound investment! Lately, there have been several articles published on the economic advantages of a college education. These articles tend to average wages together according to education and years of service. Their tabulations generally include the chairman of the board, various vice presidents and plant managers and do not reflect the achievement of the average graduate. They consistently fail to include an analysis of the investment a college education requires. In reality, the bright high school graduate would make more real money over a 20-year period if he went directly to work "on the hill" than he would if he graduated from college. Furthermore, he would find little difference between his wages and those of the college graduate in the period from 20-30 years after high school graduation.

Jan 1, 1971

Manuscripts of Papers for Presentation at Arizona Meeting, Sept. 18 to 23, 1916, must be in hands of Secretary by July 1, 1916.

Jan 5, 1916

By Arthur Hockman, Howard W. Jaffe, Howard F. Carl

THE problem of establishing practical techniques for evaluating natural corundum ores arose from the desire to improve the existing purchase specifications for crystal corundum procured by the Federal Government for stockpiling. Such purchase specifications had been developed for a large number of products, including minerals and ores considered to be critical and strategic because of the country's dependence on foreign sources of supply. It will be apparent to anyone considering the subject of purchase specifications that the determination of whether or not a submittal meets the specifications is a prime consideration. Consequently satisfactory specifications for minerals should not only incorporate physical, chemical, and mineralogical requirements that are practical but should also establish the means by which both buyer and seller can be assured that materials meet stated requirements. The Munition Board's Material Purchase Specification for corundum, dated February 1954, covered two grades of crystal corundum intended primarily for abrasive use. It established limits of size and of composition: Grade A, at least 95 pct +3 mesh and 92 pct alumina (Al2O3); Grade B, at least 95 pct +7 mesh and 90 pct alumina. It also specified that "of each lot of material, not less than 95 percent shall have a hardness equal to or exceeding nine (9) on Moh's Scale." These specifications were unsatisfactory for several reasons. They did not allow the purchase of lower grades of corundum being used by industry. Neither did they specify exactly what a corundum ore actually was, except that it should contain so much alumina and have a certain scratch hardness. Nothing was said about the abrasive qualities of the material that was to be purchased primarily for abrasive use. During the period 1946 to 1948 supplies of the two grades defined in the then current specifications continued to decrease. Early in 1949 industry recommended that the finer sizes of corundum known as "crystal corundum concentrates," ¼-in. to 16-mesh material, be added to the stockpile specifications and that lower grades of crystal corundum also be included. In the spring of 1949 the National Bureau of Standards and the Bureau of Mines were asked by the Munitions Board to cooperate in developing more practical specifications for grading natural corundum ores. The National Bureau of Standards indicated that it would investigate physical test methods for determining abrasive characteristics of corundum, and the Eastern Experiment Station of the Bureau of Mines at College Park, Md., stated that it would consider the mineralogical aspects of the problem. Members of these two agencies, in consultation with representatives of the Office of Materials Resources of the Munitions Board and of the Federal Supply Service of the General Services Administration, and with the cooperation of industrial suppliers and consumers of abrasive corundum, developed, in a fairly short time, more practical specifications for six grades of corundum ores. The new specifications, issued January 1951, were for corundum, natural crystals, as by this time high-purity synthetic corundum was available and widely used. Nevertheless, for certain specific applications the natural product was preferred over the synthetic material. It has been extensively used in forming snagging wheels. It breaks into more or less cubical particles, whereas artificial corundum fractures into splintery shapes. These produce irregular cuts in glass, while the more symmetrical shape produces a more uniform ground surface. For this reason natural corundum has been preferred for certain types of lens grinding. Pure corundum is clear, colorless alpha alumina (A12O3), but it is rarely found in nature in this form. The most important gem varieties include the blue and yellow sapphires and the ruby. Minute impurities of titanic oxide impart a blue color,

Jan 1, 1955

By B. T. Brady

Recent theoretical, experimental, and field studies conducted by the Bureau of Mines suggest that rock failures may be predicted and, in some instances, controlled. Theoretical studies that were later corroborated by laboratory and field studies predict that a seismic anomaly will precede rock bursts and/or roof falls in mines. The seismic anomaly is predicted to consist of an increase in the number of seismic events occurring in the immediate vicinity where the failure 1s nucleated. This increase will then be followed by a dramatic decrease of seismicity in a broad region that surrounds the location of the impending failure. The dimensions of this region allow a preliminary estimate of the time to failure (measured from the time the seismicity increase began) as well as an estimate of the energy that will be released at the instant of failure. Field observations indicating that this predicted behavior does precede rock bursts and a roof fall are presented in this report. Implications of results to the problem of failure control in mines that experience massive rock failures are discussed.

Jan 1, 1978

By R. M. Stewart, C. W. MacQueen

Anaconda's Berkeley pit at Butte produces 34,000 tpd of ore averaging 0.8 pct copper. Two-and-one-half tons of waste is stripped per ton of ore, approximately 40,000 tpd by the company and an added 45,000 tons by the F&S Contracting Co. The company truck fleet consists of 24 Euclid and 18 Mack 34-ton, rear-dump diesel trucks.

Jan 7, 1961

By S. Ivanova

The results presented in this paper show that the gold solution dilution is a key parameter to control the dispersion of gold on ?-Al2O3 the selected support. The variation of concentration leads to changes in pH which modify the nature of gold complexes from HAuCl4 formed in the solution. These complexes are presented. Some of them (AuCl3(OH)- and AuCl2(OH)2 -) react with the surface of alumina and give interesting interaction. AuCl2(OH)2 complex has been considered as an ideal complex because of the strong anchorage of a bidentate species on the alumina. This complex is formed mainly in a solution of gold with a concentration of 10-4 M giving a pH of 3.5-4.5. The nature of the anchorage and the amount of chlorine, has an influence upon the formation of Au-Cl bridges which modify the dispersion of the gold on alumina of the final catalyst as shown by TEM.

Oct 1, 2003

By Corale L. Brierley

An unidentified, high-temperature microbe, which oxidizes reduced sulfur and iron in an acid medium between 45° and 75°C, is studied to determine its ability to leach copper sulfide minerals and molybdenite. Copper is leached from low-grade ore as well as a chalcopyrite concentrate, and preliminary data indicate a tolerance of 1.0 gpl copper by the microbe. A molybdenite concentrate is also biogenically leached, and the microbe is able to continue growth when the soluble molybdenum concentration is 750 ppm. Molybdenum can not be biogenically extracted from waste material using the present technique. Direct observation using SEM illustrates colonial growth and developmental characteristics of the microbe on molybdenite fines. The organism responds to hexavalent molybdenum by reducing this metal to the pentavalent state in aerobic and nitrogen gas atmospheres.

Jan 1, 1974

By J. G. Groppo, B. K. Parekh

Removal of moisture from fine (minus 28 mesh) dean coal to 20 percent or lower level is difficult using the conventional vacuum dewatering technique. High pressure filtration technique provides an avenue for obtaining low moisture in fine clean coal. This paper describes a couple of novel approaches for dewatering of fine clean coal using pressure filtration which provides much lower moisture in fine clean coal than that obtained using conventional pressure filter. The approaches involve (a) split stream dewatering and (b) addition of paper pulp to the coal slurry. For Pittsburgh No. 8 coal slurry, split stream dewatering at 400 mesh provided filter cake containing 12.9 percent moisture compared to 24.9 percent obtained on the feed material. The addition of paper pulp to the slurry provided filter cake containing about 17 percent moisture.

Jan 1, 1995

By Steven Atkin, Rens Verburg, Bryony Hansen, David McWharter

The use of paste tailings as underground backfill and for surface disposal is rapidly expanding, and with it comes the requirement to understand and predict its long-term environmental stability. This paper presents the results from a kinetic testing study performed on cemented tailings paste mixtures under both subaqueous and subaerial conditions. In addition, the effects of grainsize reduction are investigated. It will be demonstrated that the long-term weathering behavior of tailings paste is controlled by its physical and chemical characteristics, as well as its placement conditions. The testing indicates that subaqueous disposal of paste inhibits acid generation, whereas the exposed samples produced acidic leachate despite the presence of cement added to meet geotechnical requirements.

Jan 1, 2000

Same-batch and non-blind as well as blind pulp duplicates are often submitted as quality assurance/quality control (QA/QC) control samples to a routine laboratory along with routine assays (and other control samples such as reference material samples). The current ways of interpreting the results of duplicate assays to derive QA/QC conclusions and decisions, however, has not yet been formalised in a scientific manner. The current, prevailing approach and its limitations are reviewed and a new method is proposed as a substitute tool. This new tool should allow for operational error detection on a batch per batch basis (ie batch rejection) as well as laboratory performance assessment with time on reproducibility.

Jan 1, 2008

By Sukumar Bandopadhyay, Arunapuram Sundararajan

"For the last three decades, the application of network planning has provided a basis for a formal and general approach to the discipline of project management. For fixed activity duration, a very simple algorithm commonly known as critical path method (CPM), gives the length of time required for the total project as well as indicates the activities which are vital to the completion of a project. Project Evaluation Review Techniques (PER T) on the other hand, generalize the above approach to recognize uncertainty in the activity durations by allowing them to be random variables. One of the misleading aspects of current "" PER T"" solution method is, however, the implication that there is a unique critical path. In general, any number of paths could be critical, depending on the particular realization of the random activity durations that actually occur. In this case, simulation can be utilized to estimate completion time of a project.In this paper, the concept of criticality indexing is discussed, and a simulation model application which defines the critical path based on the criticality indexing concept, to a longwall development - extraction network, is presented. The model also provides suitable scheduling of resources based on the resource constraints and smooth s out period-t o-period assignments. IntroductionThe successful management of large-scale projects require careful planning, scheduling , and coordinating numerous interrelated activities. To aid in these task s, formal procedures based on the networks and network techniques (variously called PERT or CPM) were developed. In its original form the completion time for individual activities of a project was assumed fixed and known in advance: this in turn led to the familiar algorithms for computing the critical path, earliest start time, slack, and so forth. The unreality of such an assumption is, of course , apparent in many contexts. Consequently, attempts were made to introduce probalistic activity completion times, allowing representation of the stochastic nature of most projects."

Jan 1, 1987

By L W. Morley

The Division is concerned with physical methods as applied to geo-logical research and mapping. An at-tempt is made to describe long-term goals, illustrated by examples of projects in the fields of aeromagnetic interpretation, palaeomagnetic re-search, Pleistocene and groundwater geophysics, seismic surveying, electromagnetic research and instrument development. Cooperative projects in surveys and research, with universities, private companies and provincial organizations, are frequently undertaken. An outstanding example of this is the recently approved Federal-Provincial Aeromagnetic Survey Plan, the purpose of which is discussed both from an economic and a scientific point of view. HISTORY OF THE DIVISION M AGNETIC, electrical, seismic and gravity methods, as a means of extending the geologist's sphere of observation beyond the head of his hammer, came into wide-spread use for the first time after World ?war I. Interest in these methods was aroused amongst geologists of the Geological Survey and, in 1928, a group of these geologists and university

Jan 1, 1963

By Hiram Brown

The problem of stress corrosion has been discussed a great deal recently, but many factors have as yet not been clarified. There are many interpretations of the definition of the word, different corrosive media are used, and numerous methods of stressing are utilized. Some quarters believe that the inherent strength of the material under test is the determining factor of its resistance to stress corrosion, while others think that the natural corrosion resistance of the material is the determining factor. This paper is intended merely to set forth the limited experience we have had and to discuss some of the other stress-corrosion tests which have been made with light alloys.

Jan 1, 1945

By Marshall B. Standing, Donald L. Katz

Density data are reported on 16 saturated hydrocarbon vapors at Pressures ranging from 1000 to 8220 Ib. per sq. in. and at temperatures ranging from 35° to 250°F. These data have been used to extend the compressibility-factor chart for natural gases up to 10,000 lb. per sq. in. The relatively large quantity of high-boiling constituents present in high-pressure vapors in equilibrium with crude oils makes it necessary to include in the analysis of the gas the molecular weight, density, and possibly boiling range of the heptanes and heavier fraction. Relationships have been presented by which the density of gases may be obtained directly from the temperature, pressure, and gas gravity provided the gases have a common source or are similar in composition. Introduction The densities of natural gases are necessary in many engineering in in petroleum production and utilization, Gas reserves, changes in reservoir pressure, gradients in gas wells, metering of gases, pipeline flow, and compression of gases are typical problems requiring the density of the gas. A decade ago, engineering computations used ideal gas laws with deviations up to 500 Ib. per sq. in.4 Recent discoveries of pools having Pressures UP to 7500 lb. Per sq. in., and installation of pressure-maintenance and recycling plants, have increased the need for data On gas density at high pressures. Methods of Computation The accepted method of computing the density or specific volume of natural gases is the use of the ideal gas law corrected by a compressibility factor. The method proposed by Kay7 of correlating compressibility factors for gaseous mixtures on pseudocritical properties5 appears to be satisfactory for natural gases.2 The meth-me-compressibility factor has been shown to deviate systematically from the behavior of natural gases2 and a chart giving these corrected factors is available. A method of computing specific volume of gaseous mixtures from partial molal volumes has been reported by sage and Lacey.8 Complete data for the computation are not yet available for all hydrocarbon gases. Most- of the reported data on gas densities have been in the single-phase region removed from the dew point or saturation condition. Since most gases in the reservoir Or while on contact with liquid '''ring flow are saturated, the determination of densities under conditions of saturation is particularly important. Although there is no reason to believe that the saturated gases differ in behavior from those consider. ably removed from their dew points, the usual experimental determinations find difficulty on approaching the dew-point conditions, This paper reports the density of I6 saturated gases in equilibrium with crude oils. The relationships developed to compute the density of gases to high pressure' have been modified and enlarged. A simpli-fied method of obtaining gas density is presented in the Form of charts, which apply for specific groups of gases.

Jan 1, 1942

By P. Majani, F. P. Kokesh, M. Grosmangin

Determination of the quality of cementation of casing in oil wells in the past has involved inflow and circulation tests to insure that the producing zones were adequately sealed off from the adjacent zones. Existing logging methods, such as temperature and radioactivity surveys, may detect the presence of cement behind the casing. However, the qualities of the cement (i.e., its hardness and particularly its bond to the casing) are not indicated. The new logging method described in this paper operates on the principle that the attenuation of a sonic pulse transmitted by a casing is greatly increased when that casing is bonded to an outer annulus of hard material (such as set cement) which has an appreciably smaller sonic-wave velocity than that of the casing. The down-hole tool contains a source of recurrent sound pulses which are detected by a receiver spaced a few feet from the source The amplitude of the detected casing-borne pulse is measured, and the resulting signal is transmitted to the surface where it is recorded vs depth. Since amplitude is a function of attenuation, the log is readily interpreted. Laboratory studies have shown straightforward relationship between attenuation and such variables as source-detector spacing and per cent of circumference bonded. It is shown that cement not set or not bonded to the casing has compara- tively little attenuating effect. Field examples show not only the cement top, but also the variation in cementation quality below the top. Further, the increase of bonding with time and after squeeze cementation is depicted. The detection of poor cement jobs is confirmed by production tests and by formation-test results. It is anticipated that the method will have wide application in evaluating cementation quality prior to formation testing in completions and recompletions. The analysis it affords may aid in further improving cementation techniques. INTRODUCTION The main purpose of oilwell cementing is to isolate a production zone from other undesirable zones. To investigate whether this purpose has been accomplished, several logging methods have been used such as temperature logs, radioactive tracer logs, etc. While these logs all respond to the presence of cement behind the casing, they do not indicate the degree of bonding of the cement to the casing. Early in the application of sonic logging, it was noticed that considerable attenuation of sound signals takes place in cemented pipe and is often made evident on the standard Sonic log by cycle skipping.' The development of a circuit capable of continuously recording the amplitude of the casing-borne sound signal has made possible an extensive series of laboratory and field tests, which gave the following results. The amplitude of a sound signal after it has traveled in a firmly cemented pipe is only a small fraction of that recorded by the same device in free pipe. This provides a wide spectrum of energy levels; for given local conditions, empirical values of the amplitude can be correlated with the quality of cementation. Interpretations made in this manner generally have been confirmed by production tests, circulation tests and squeeze cementation. The purposes of this paper are to give a general description of the new logging method and to present some laboratory and field results. CYCLE SKIPPING Early attempts to study the quality of the cement behind the casing were performed with a standard Sonic log, which measures the transit time At, and were based on the well known phenomenon of cycle skipping.' Cycle skipping normally is interpreted as being a manifestation of weak signals at the receivers. The log of Fig. 1 was run with the recording instrumentation adjusted to enhance cycle skipping. A mirror-image presentation was used for better visual interpretation. The transit time of sound in steel is about 58 microseconds/ft (corresponding to a velocity of 17,000 ft/ sec), and the portions of the log where this value is recorded are interpreted as zones with no cement bond. Where cycle skipping produces a higher value of At, weak signals (or a high rate of attenuation) are indicated, and a good cement bond may be present. The occurrence of cycle skipping, however, depends too much on instrument adjustment to give a uni-