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By Z. C. Song

[THIS PAPER WAS TRANSLATED FROM CHINESE TO ENGLISH BY S. S. PENG, WEST VIRGINIA UNIVERSITY] Immediately after coal extraction, the pressure that causes the movement of the surrounding strata is called mine pressure. Through the strata movement, certain features such as supports taking load arise. This is called "manifestation of mine pressure". The existence of mine pressure is ab¬solute whereas its manifestation is relative and conditional. The visible movement of the surrounding strata occurs only when the applied pressure exceeds the plastic breaking strength. Me support begins to take load only when it offers resistance to the strata movement. The key to investigating mine pressure and its control hinges on understanding the rules and conditions for the manifestation of mine pressure. Since the face moves continuously, the mine pressure and its manifestations are also constantly changing. 'Therefore, it should not only emphasize to obtain its instantaneous magnitude, but more importantly the rules of development changes and their relations to the movement of overlying strata. Once this is resolved, one can estimate the movement of the overlying strata through mani¬festation of mine pressure and predict the time and magnitude of incoming roof weighting. Consequently the location and timing of rib excavation can be correctly selected and thus solve several major problems in the design of mining operation.

Jan 1, 1982

By N. W. Shed

The specifications for bridge-steel are usually not severe. The main difficulty is to secure a material which will roll easily, without showing signs of cracking on the corners of the blooms or on the flanges of the beams. In many mills sulphur has been deemed the most harmful constituent in this respect. It has been thought hazardous.to roll steel containing over 0.07 per cent. of sulphur. Yet, in making steel for the Phoenix Iron Company, I have produced from stock running as high as 0.13 per cent. of sulphur a material which rolled very satisfactorily. It is reasonable to infer that the injurious effect of sulphur can be neutralized, to a great extent, by proper treatment in the open-hearth furnace; and the following notes from my usual practice here may be of interest to those obliged to use high-sulphur stock. The steel made at Phoenixville in the 20-ton furnaces has about the following composition : Per cent. Carbon,...0.15 to 0.20 Manganese,.........0.50 to 0.60 Sulphur,..........0.11 to 0.13 Phosphorus,.: .0.04 to 0.06 Silicon,.......... 0.01 to 0.02 The best running heats were made with a small amount of pigiron. In using large proportions of pig the quantity of ore is also increased. This not only cuts the bottom, but also lengthens the time required to bring the charge down. Up to 50 per cent. of pig may be used, but 25 per cent. is much better. A 40,000-pound charge, containing 10,000 pounds of pig and 30,000 pounds of Bessemer butts or beam-scrap, works very well.

Jan 1, 1890

By Rachel De Lucas

Current methods of hydrogen storage are an impediment to the transition of our energy infrastructure from a hydrocarbon to a hydrogen base. The transportation, handling, and storage costs of hydrogen gas account for a majority of its selling price. Magnesium hydride slurry is a safe, environmentally friendly alternative for hydrogen storage. If this form of storage is to be adopted on a large scale, a cost-effective method for recycling the enormous amounts of magnesium hydroxide byproduct must be identified. The solid oxide membrane (SOM) process can be used to recycle the magnesium hydroxide byproduct into magnesium metal, which can be reformed into magnesium hydride and reused for fuel storage. Conventional magnesium extraction/recycling technologies require a great deal of energy and create byproducts that are harmful to the environment and human health. The SOM process poses none of these detrimental effects and requires less energy and feed preparation. The economic viability of a facility that utilizes the solid oxide membrane process for the direct reduction of magnesium must be examined in more detail if industry is to consider it. Cost analysis data related to the commercial viability of a scale-up will be compared to two standard industrial processes: current magnesium production techniques including electrolytic and metallo-thermic processes. We have shown in our cost comparison that the SOM process is cheaper than these traditional techniques and that it is also comparable to aluminum's Hall-Héroult process in cost but with none of the environmentally harmful byproducts.

Jan 1, 2006

By J. D. Smit, K. C. Garner, P. C. van Aswegen

The initial results obtained from the implementation of computer-controlled strategy on the milling circuit are reported. An analysis of these results showed that a peak-power pebble-mill controller on a high throughput hardrock wet-milling circuit reduces the stability of the system. It was concluded that the milling circuit should be regarded as a single system in which the measurement of grinding efficiency, circulating load, product size distribution, and feed rate should minimize the product variance and maximize the feed rate according to the grinding power available. Work is proceeding on such a system.

Jan 1, 1980

By B. K. Sternberg

Since 1986, we have developed a series of electromagnetic (EM) sounding systems at the Laboratory for Advanced Subsurface Imaging (LASI). These may be categorized by their frequency ranges: low frequency (LF, 30 Hz to 30 kHz), medium frequency (MF, 1 kHz to 1 MHz), and high frequency (HF, 30 kHz to 30 MHz). We have applied these EM systems to a variety of targets, including: mapping of plumes of contaminated groundwater, tracing leachate for an in-situ leaching operation, locating buried hazardous waste, identifying subsidence-prone zones and detecting buried voids. These systems are also applicable to exploration for ore bodies. Currently, our sounding system uses a vertical magnetic field vector. Previous systems of this type required a slow and relatively inaccurate manual rotation of the sensing coils. The systems also used occasional calibrations of the measuring system. We have developed a 3-dimensional mathematical rotation procedure for the data, as well as a simultaneous, high-accuracy, calibration method. These new developments have greatly increased the speed of the measurements, as well as improving the accuracy of the ellipticity data. We use stepped-frequency measurements along with narrow-band filtering to allow accurate measurements, even in high-noise areas. We typically obtain ellipticity measurements at eleven frequencies and along densely sampled profile lines. We use neural networks to help interpret the measured ellipticity patterns. Neural networks can be trained to relate the measured ellipticity patterns to earth resistivities or to discrete targets buried in the earth. The neural network training may use theoretical EM responses calculated from computer codes for relatively simple structures. The theoretical EM response for many complex targets that are of interest cannot currently be reliably calculated, even with the largest supercomputers available. We have therefore chosen to do some of the training using theoretical EM responses generated in a full-scale modeling tank located at our Avra Valley Geophysical Test Site. We have also developed data-visualization software to help interpret the large data sets produced by this system.

Jan 1, 1997

By J. R. Katan, J. R. Ball, Peter R. Bannister, F. J. Williams

During the last week in March and the first week in April, 1973, the Naval Underwater Systems Center measured the 76 Hz magnetic field strength (in Wisconsin and Texas) produced by both the elevated and (newly installed) buried Wisconsin Test Facility (WTF) north-south (NS) antennas. The principle result obtained from these measurements is that there is no measurable difference in performance between the WTF buried and elevated NS antennas.

Jan 1, 1973

By John W. Cabot

The following series of analyses, which may, be of interest to Bessemer-steel makers, is submitted as a contribution to the muchvexed discussion of manganese in Bessemer steel. They were made by the writer in the spring of 1881, at the works of the Pittsburgh Bessemer Steel Company Limited, during a' period of about eight days, part of. which time the rail-steel showed great variation in rolling qualities. During the first part of tile time in question, it rolled well; later on it began to roll wome until, finally, it cracked very badly, reaching its worst stage. After this it rapidly improved until it again rolled smoothly. During this time of transition from good rolling to bad, and hack to good again, the course of the manganese was followed quite closely. It is the striking correspondence between these varying manganese contents and the differences in rolling which is here presented as worthy of notice. The other ordinary elements were determined occasionally, but showed no. unusual variation: The steel, in question, was ordinary rail-steel of about the following compusition : C=35. P - .08. Mn - .98. Si = .08. 8 = .06. The samples for manganese determinations were taken at first from an average of two days' work, and later on, when the steel

Jan 1, 1882

By Patrick A. Ley

Maintaining, managing and manipulating large quantities of geologic data can be a very costly and time-consuming process. The use of computer-based methods can provide some relief to the problems of editing, displaying, and interpreting spatial geological data. ENCORE is a system designed specifically for coal orebody modeling and reserve esitmation where the geologic data is stored on a large mainframe computer and is accessed from a local work station for editing, manipulating, and producing various reports and high-quality engineering maps. The ENCORE system was designed for use by the geologist or mining engineer with little or no computer background and, additionally, it was designed to provide the geologist or mining engineer enough flexibility to be able to select the appropriate methodology for the orebody being analyzed. The various analysis tools incorporated into ENCORE can significantly increase the professional's productivity without burdening he or she with the need to understand the details of the internal computer language.

Jan 1, 1982

By Quin Dennis

Process Optimization ?What is it really? It is NOT ?a larger fan to increase draft through a process ?a larger pump on a wet circuit ?a wider conveyor belt for solid materials ?a larger feed elevator into or out of a process These relieve individual constraints ??bottlenecks??and allow operation to the next constraint in the process ?It is also NOT about automating the operator ?which captures consistency but is not continuous optimization

Nov 1, 2011

By Blair Burwell

This paper describing the method of mining a deposit of vanadium ore near Rifle, Colo., is one of a series of similar papers on metal-mining methods and costs being issued by the United States Bureau of Mines. This vanadium deposit probably is the largest yet found in North America. It is situated 12 miles northeast of Rifle, Colo. (see fig. 1), on the southern flank of tae White River plateau, and is at an altitude of 6,500 feet. Between 150 and 200 tons of ore are mined daily and trucked to the mill at Rifle. The product of the mill is fined vanadium oxide, which is shipped to the company's plaits at Columbiana, Ohio, and Niagara Falls, N. Y., for the electric manufacture of ferrovanadium. HISTORY The deposit was discovered about 1909 by men prospecting for carnotite. Its outcrop on the bola cliff of Rifle Canon had been known to stockmen for many years.

Jan 1, 1932

By Paul C. Lingo

Two recent antitrust cases, coming from widely separated areas, different industries and involving wholly different facts were decided by the Supreme Court on June 7, 1965. The decisions in there two cases may well prove to be the most important and far-reaching decisions in the field of labor law that have been handed down in the last 24 years. These cases, although quite dissimilar factually, had one common element. In both, the gravamen of the antitrust violation was bottomed on the terms of labor agreements negotiated by a multiemployer group. These cases are usually referred to as Pennington1 and Jewel Teat. Since a number of references will be made to the antitrust laws, it may be well to state briefly the applicable portions. Section 1 of the Sherman Antitrust Act makes "every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several states, or with foreign nations, is declared to be illegal...". Section 2 imposes criminal sanctions against "Every person who shall monopolize, or attempt to monopolize, or combine or conspire with any other person or persons, to monopolize any part of the trade or commerce among the several states...". Under Section 4 of the Clayton Act a person who sustains damages as a result of a violation of the anti¬trust laws is entitled to recover treble damages plus costs.

Jan 1, 1966

By K W. Bian, Y M. Liu

Tongkuangyu Copper Mine is currently the only mine in China employing block caving. It comprises two large orebodies known as the No 4 orebody and the No 5 orebody. They are approximately 50° in dip angle, 80 to 240 m in width and 800–1000 m in strike length. The two orebodies are separated by a distance of 110–130 m. Production with block caving originally, ie Phase 1 project started at Tongkuangyu from the first undercut at a depth of 200–300 m below the ground surface and designated as Lift 810 m in late 1989 and has continued to the present. During the last 25 years Tongkuangyu has mined three lifts: Lifts 810 m, 690 m and 530 m. The previous two lifts utilised a slusher process with an annual designed production rate of 4 Mt. In this context the lift name represents the elevation of track haul level.The Tongkuangyu Phase 2 project serves for two lifts (ie Lift 530 m and 410 m) under the elevation of 690 m and the annual designed production rate is 6 Mt. Since the orebody is approximately 50° in dip angle, it is originally designed that production at Lift 530 m is comprised of one main extraction level and two auxiliary extraction levels in the footwall and undercutting is started from one end of the extraction footprint forward to another end, which is from north-east to south-west.Production at Lift 530 m started from March 2011 and reached to 6.39 Mt in 2013 and 6.9 Mt in 2014. Additionally, Tongkuangyu improved block caving processes and used modern mining equipment, which differ from the previous two lifts. Blastholes for undercutting and drawbell-preparation are now drilled using jumbos. The blasted ore is transferred to the underground crushing station via 10 t electric load-haul-dumps (LHDs) and then delivered to surface via a belt conveyor 3200 m long.Due to increasing ground pressure, a consequence of mining depth increase, stress abutment and inadequate support, significant damage occurred at the Tongkuangyu Copper Mine with production at Lift 530 m. This resulted in significant production delays and rehabilitation costs. A series of improvements have since been implemented including an advanced undercut sequence and increased ground support. All of these improvements have allowed Tongkuangyu to alleviate ground control issues, reduce operating costs and ensure safe production.CITATION:Liu, Y M and Bian, K W, 2016. Production at Lift 530 m of Tongkuangyu Copper Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By N. M. Parikh, T. J. Koppenaal

The strengthening mechanism of fiber-reinforced silver has been investigated as a function of fiber density and fiber material. Stress-strain curves were determined in the range 2 x 10-6 to 2 x 10-3 plastic styain and slip lines were examined. The yield strength at 0.2 pct permanent strain is markedly dependent upon fiber density but the stress necessary to initiate plastic deformation is independent of fiber density. The strengthening mechanism of the fibers is shown to be malogous to grain boundary strengthening in poly crystalline metals. The variation in strengthening with different types of fibers is also noted and discussed. In recent years, considerable progress has been made in the understanding of the mechanical properties of two-phase systems, particularly in the classical dispersed-phase alloys where the separation between the dispersed phases is 0.01-0.1µ. However, little work has been done on fiber-reinforced metals where the dispersed-phase separation is considerably larger than this. Parikh1 investigated the mechanical properties of many fiber-reinforced metals and found that two general relationships are always observed, as follows: 1) A fibrous network incorporated into a second weaker metal strengthens the latter, and the amount of strengthening increases with fiber concentration. 2) At a corrstant fiber concentration, the amount of strengthening in a given matrix can vary considerably, depending upon the type of fiber employed. The object of the present investigation was to examine the fuiidamental factors controlling these two observations. procedure: Fig. 1 shows the initial step in the fabrication of the specimens. The sieve is shaken so that the fibers fall into a mold with the longitudinal axes of most fibers in the X-Z plane. The fibers are then compressed to a predetermined density, thus forming a "felt", and the necessary amount of matrix metal is added to the top of the felt. The mold is heated, in vacuum or hydrogen, to above the melting point of the matrix metal; the molten metal flows into the felt, and the entire assembly is cooled. This produces a "composite" that is essentially free of voids. A number of composites were prepared in this manner using 1/4-in. kinked lengths of mild steel

Jan 1, 1962

By Don Coulter

OBSERVATIONS were made over a period of seventeen months to ascertain the economic value of a four-cycle Miller engine direct-connected to a Watts compressor, to determine whether this type of engine could compete suc-cessfully against the old type of two-cycle engine in general use. The accompanying tables show the data obtained. The first, over a period of seventeen months, compares the operating cost per hour and cost per horsepower-hour with

Jan 8, 1928

By A. Kapito

The formation of bainite in steel is dependent on the size of the casting, the heat treatment, and the alloying elements. It is difficult to obtain a fully bainitic microstructure in steels during heat treatment because of its close proximity to the martensite (a?) reaction. The ferrite (a) and pearlite reactions in steels are also rapid and shield the bainite reaction. Alloying elements therefore need to be added to separate the bainite reaction. Boron (B) and molybdenum (Mo) are key elements added to bainitic steels because of their ability to retard the a reaction. Other elements used in the production of bainitic steels are silicon (Si), chromium (Cr), manganese (Mn), and titanium (Ti). In this paper we investigate the effect of alloying elements on the bainite reaction through the use of dilatometry. Dilatometry is a technique that determines phase transformations in the steel and through which continuous cooling transformation (CCT) curves can then be developed. Some initial results are presented of an ongoing study on the development of bainitic steels for railway wheel applications.

Jan 1, 2013

By P. K. Songfack

The transport of slurry within the ball mill depends on the peripheral velocity and porosity of the ball charge. Residence time distribution and mill hold up are of-ten used as indicators of the mode of transport. In this work, the transport problem is tackled via direct simulation of the three dimensional motion of the ball charge. In doing so, the following quantities are calculated: (i) ball size distribution as a function of the distance from the feed end of the mill (ii) mean peripheral and longitudinal velocity and longitudinal velocity of balls of different sizes, and (iii) the spatial distribution of porosity within the ball charge. Hence, the problem of transport is handled as a motion of part of the slurry with the ball charge and part as hydrodynamic flow through the porous structure.

Jan 1, 1993

By C. A. Heiland

For a long time it has been known that it is possible to deduce conclusions about the physical constitution of the interior of the earth from the records of natural earthquakes obtained by stationary seismographs. In view of this fact it is surprising how late, relatively speaking, geologic prospecting by seismic methods has been taken up, although the first suggestion was made 40 years ago—that travel-time curves of artificial explosions might be used for the study of the change of the velocity of seismic waves as depth. Further suggestions of practical applications of artificial explosions for geologic purposes were made by Belar12 by von dem Borne,3 by Benndorf and by Galitzin,5 but it was not .until 1919 that Mintrop obtained a patent on the seismic prospecting method which he has applied commercially on a large scale ever since. Dr. Mintrop came to this country with his method at about 1923. Since that time, several American oil companies have developed seismographs of the mechanical type for the vertical component similar to that of Mintrop's (Humble Oil Co., Dr. Ricker). Other consulting geophysical companies designed other types of seismic devices, the simplest of them for the recording of the first impulse being the geophone (McCol-lum Geophone Co.). The galvanometric recording method as first proposed by Galitzin is being used (Geophysical Research Corpn.?) and use is being made even of the piezoelectric properties of crystals for portable seismographs (F. Rieber). There is such an enormous variety of all kinds of portable seismographs, vibrographs, accelerographs, etc., that it is difficult to decide just what kind is preferable. Unfortunately, nothing has been published as yet about American designs of portable seismographs, except the Wood-Anderson torsion-seismometer. After Mintrop's design of portable seismographs, other constructions were made

Jan 1, 1929

By J. C. Osler

The design of a tailings dam is a geotechnical engineering project of considerable scope. For the design, it is necessary to establish the engineering properties of the soil or rock strata which will support the dam and the tailings or other fill which will be used to construct the dam. The various field and laboratory investigations which are necessary to obtain the required design parameters are discussed in the paper and the use of these parameters to compute stability, settlement, and seepage are considered. The designer of a tailings dam can never assume an absolute knowledge of the properties of the foundation strata. Further, initial design assumptions are often approximate, particularly with regard to the distribution of pore pressures through and beneath the dam. Thus, the installation of performance monitoring instruments is recommended, since data obtained from such instrumentation can be used to check the stability of the structure both during construction and after its completion.

Jan 1, 1972

By G. M. Furnival

A PROGRAMME of structure drilling was commenced in the Southern Alberta Plains in June, 1943, for the purpose of determining the geological structure of the underlying sediments. More than 270 holes have been drilled throughout an area of some 1,800 square miles or 1,000,000 acres (see Figure 1). The Southern Plains of Alberta are covered by a mantle of glacial drift,' at places exceeding 200 feet in thickness. Only where this mantle has been dissected by deep drainage channels is bed-rock exposed to any great extent. Along such channels, surface geological mapping can be conducted to ad- vantage. Accordingly, geological mapping was commenced _in 1942 and continued each season to the present. To supplement this information, a survey of the water wells was carried on in conjunction with the mapping. However, to obtain more positive and evenly distributed structural control throughout the area as a whole and to define more adequately structural trends indicated by the preliminary mapping, it was necessary to resort to the use of drills to penetrate the glacial mantle. Various types of light drills are commonly used for this purpose and provide geological information in the form of drill cuttings, cores, drilling time rates, etc. Correlation of information is generally obtained through comparison of cored sections, drill cuttings, micro-fossils, and drilling time rates. However, in this case the holes were electrologged and correlations were made chiefly by comparison of such logs. The data so obtained is plotted and portrayed in the form of structure contour maps on recognizable stratigraphic horizons and in the form of isopach maps of the recognizable stratigraphic intervals penetrated in the holes. This method had not been widely used in Alberta previously and the technique employed was necessarily developed after the project began.

Jan 1, 1945

By E Kasai, T Nakamura, E Shibata

In the present study, formation of PCDD/Fs from carbon particles like æsootÆ, so called de novo synthesis, was experimentally simulated using the powder mixture of graphite and metallic chloride. Composite states of graphite and chloride particles were varied by the preliminary treatment, ie high-energy ball milling for different time or heating at different temperatures. These samples were subjected to the measurement of the rates of weight loss mainly due to the oxidation of carbon, the formation of absorbent organic chlorides (AOX) and the formation of PCDD/Fs at 300¦C. The amount of PCDD/Fs formation increased by applying certain pretreatments. Further, linear relationships were obtained among the formation rates of PCDD/Fs and AOX and the weight loss of sample. These results will give useful information to investigate the mechanism of PCDD/Fs formation from unburned combustible carbon and hydrocarbon in thermal processes.

Jan 1, 2002