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By André Vervoort

At the 2017 ICGCM-conference in Morgantown, WV, a case study was presented with measurements of the upward surface movements or uplift after the closure of two neighboring coal mines (Winterslag and Zwartberg, Belgium). One was closed in the sixties, and the other closed in 1988. The study was based on satellite data (Radar-interferometry or InSAR). The analyses showed both a significant variation of uplift values above the mined area and the surrounding zones, and a variation of the uplift rate as a function of time. In other words, the phenomenon of uplift is complex. At that time, it also was clear that more research was needed to better understand this phenomenon, e.g., an identification of the various mechanisms that are relevant for the process of uplift and the quantification of the various impacts. A systematic analysis of all relevant parameters resulted in a framework that forms the basis for the analytical calculations of uplift values. These calculations show that the main impact is due to changes in the hydrostatic pressure. However, the expansion of the softest parts, i.e., the collapsed or goaf material, is not only important, but the expansion of the (stiffer) non-collapsed strata layers due to a change in pore pressure also must be integrated into the model. For the case study, the partial flooding of the underground after closure of the mine that was abandoned in the sixties is integrated into the model. Larger stiffness values also are applied for this mine, in comparison to the values of the more recently closed mine. Overall, a very good correlation is observed between the InSAR-measurements and the calculated values along a north-south transect.

By Jae R. Lee

Keywords: Self-propagating high temperature synthesis, AlN, Powder synthesis The particle size and shape effects of starting raw powders on the synthesis of aluminum nitride by self-propagating high temperature technique under high nitrogen pressure were investigated with various AlN diluents and Al reactants. It was found that the structure of beds of the starting raw particles largely affected the pore channels for nitrogen gas infiltration as well as the passages for combustion propagation before and during the reaction, resulting in the morphology and purity changes of the synthesized products. The AlN product of purity over 98% with about 30 microns was obtained.

Jan 1, 2005

By R. F. Shurtz

The problem of estimating the precision of systematic samples from a mineral deposit is attacked by interpolating the quality, or other attribute measured, by using Fourier approximation. Such approximation using trigonometric functions yields a particularly simple expression for the variance of the mean value of the attribute sampled. The increasing volume of publication in which the science of statistics has been applied to the problem of predicting the quality of an ore deposit from sets of samples taken from it might lead one to believe that engineering judgment can be replaced by statistics. There is, in fact, an implicit application of the principle of indifference or of "no advance knowledge" which has been discredited in modern statistical theory and practice. These pages will show that it is not always advantageous, efficient, or safe to apply this principle. This problem will be dealt with by using series of orthonormal functions to describe the distribution of the quality of ore in space as contrasted with the more commonly used distribution of quality as a frequency function. Mining engineers are rarely well acquainted with the use of such series or of the functions comprising them. These uses are commonplace in the fields of communication and information theory and it is not surprising that applications taken from these fields should be found appropriate for the analysis of the information contained in a set of samples from an ore deposit. It is hoped that presentation of the following basic, but incomplete, results will generate wider interest in this method and a fuller development of it as well as of the necessary computational techniques. FUNDAMENTAL PREMISES Random variables in the strictest sense are not very common in mine sampling. The sets of samples are almost always taken systematically and are, hence, not subject to all the laws governing random events. Therefore, unless there is indeed random experimental error in the determinations of quality, the treatment of systematic samples of n members as though they were random samples of n members often leads to calculation of confidence limits for the mean quality which are larger than they should be with the result that unnecessary additional sampling is done. The reason for this will emerge in the following discussion leading to Eq. 24 and its generalization. In order to inquire into such questions on a rigorous basis and at the same time avoid arithmetic complications that would obscure the concepts involved, a one dimensional distribution of quality will be assumed. The quality, Q, in suitable units is expressed as a function of the distance, x, along some straight traverse of the deposit. Such a function

Jan 1, 1967

By E. S. Leaver

The gold that is not recovered by a particular process is refractory to that process. A study to determine how the refractory gold is associated in the ore constituents usually indicates the needed improvement in the process or additional methods for bettering recovery. In preliminary work, segregation of the various minerals, gangue or impurities, and data showing the reactions of each in the recovery method readily confines the refractory gold to a certain part on which extensive research can be directed. In this dissecting plan, the microscope is an important aid in locating the refractory gold but should be supplemented by chemical tests.

Jan 1, 1934

By R Fox, R Watt

On behalf of ICI's group of explosives companies around the world, a research programme is being undertaken to develop a new electrical shotfiring system which will have markedly improved safety features and operational advantages over existing initiating systems. The paper describes the development of the 'Magnadet' Electric Detonator and 'Magna' Primer and the field experience to date. It also indicates those areas where further work is being carried out on modification of the basic designs to meet specific application requirements.

Jan 1, 1981

By T DePetris, B B. Beamish

There has been a gradual increase in the volume of internationally traded thermal and coking coal, with emphasis on blending of coals rather than single coal usage. New Zealand can take advantage of this situation, especially with its low ash and sulphur content coals. However, there is a need to clarify the thermal and coking behaviour of these coals as they relate to other market players, to benefit both the consumer and supplier. The high volatile matter contents of New Zealand coking coals are due to their high vitrinite content, which causes them to demonstrate stronger coking properties over a wider rank range than Gondwana coals. These same high vitrinite levels appear to correspond with lower initial softening temperatures than for Gondwana coals of similar rank. Preliminary results using thermogravimetric analysis also suggest that New Zealand high volatile bituminous coals can be used to substitute for higher rank Gondwana coals in combustion processes.

Jan 1, 1994

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By C. A. Worner

THE meeting of the Petroleum Division at the Annual Meeting of the Institute maintained the high standard set in previous years, and attendance of member: of the Division was at a new high. The impact of the war was evident not only in the tone of many of die papers but also in the presence at the meeting of many of our members now serving in the armed forces of our-country. Ken interest was manifested in all papers presented and the discussions which followed developed many additional facts of interist and importance. The first activity of the Division was the joint meeting of the Papers and Programs and the Publications Committees on Monday afternoon; at which time definite plans were formulated for a simplification and co-ordination of the work of the committees.

Jan 1, 1944

By W. H. Justice

Cycling operations have been successfully conducted in the La Gloria Zone for eight years. The cycling of this zone is now virtually completed. It is proposed that this report shall review the cycling operations of this reservoir so that the industry can more accurately evaluate the cycling process as a production method. The La Gloria project is one of the largest cycling operations in the State of Texas. The gas rights in the field are unitized in three operating units. By mutual agreement Magnolia Petroleum is the designated operator of the project for the 12 operators owning the gas rights. The La Gloria Corp, is the owner and operator of the cycling plant. The development and operation of the field are under the direction of an Operators Committee comprised of a representative of each operator. The Operators Committee is assisted by an Engineering and Geological Sub-Committee. The La Gloria gas field is situated approximately three miles north of Fal-furrias, Tex., and lies principally in the extreme south end of Jim Wells County, with its outer limits extending into the north end of Brookes County, Tex. It is a simple elliptically-shaped dome which has a closure of 350 ft. The field encompasses a surface area of 5,500 acres. The gas reserves are found in 20

Jan 1, 1950

By José Gonzales

"Una rampa es uno de los aspectos más importantes de la planificación a cielo abierto- en tanto se define como un camino con cierta pendiente que se desarrolla desde la parte superior del tajo hasta la parte más profunda del mismo. En ese sentido, el presente texto señala la ecuación que describa una rampa en 3D de un tajo abierto, a través de los parámetros constantes de diseño el desarrollo de la rampa. Entre los parámetros considerados tenemos: ancho de la rampa, pendiente de la rampa, ángulo interrampa del tajo, radio de la base superior del tajo (máxima área superior que engloba toda la fase), radio de la base inferior del tajo (mínima área de trabajo para los equipos). Una vez desarrollado el diseño de la rampa en función de los cinco parámetros anteriormente descritos, se podrá determinar mediante la codificación de un software denominados UNI-RAMP, el número de vueltas que requerirá la rampa para llegar al fondo del tajo, la profundidad total del tajo y el ángulo global del tajo. "

Dec 1, 2015

Although forty-seven years have passed since the by-product coke oven made its successful commercial appearance, it is only during the past fifteen or twenty years that this system of coal carbonisation has advanced rapidly to its present position ofabsolute supremacy.Early designs of by-product ovens proved more or less faulty, and the coke produced was so inferior to coke made in beehive ovens that there was a natural hesitancy on the part of coke producers to invest large sums of money in installations of by-productovens of doubtful utility-more especially in view of the fact that beehive ovens could be erected cheaply and operated by non technical labour for the production of high-grade coke under the most variable conditions of trade.Surely and steadily designers brought forward by-product ovens of improved type, coupled with more efficient apparatus for the recovery of by-products, but still the industry lagged, due almost entirely to the insistence on the part of coke users that the qualityof ordinary beehive coke was vastly superior for metallurgical operations to the best coke produced from by-product ovens. So deep rooted was this prejudice that only the passage of time could eradicate it. That it has successfully done so is strikingly illustratedin the following statistics:

Jan 1, 1928

The development of information concerning mesothelioma in South Africa started with the 1959 finding of Dr. J. Christopher Wagner of cases of mesothelioma in persons living in the vicinity or working in crocidolite mines in Cape Province. After more than 40 years, the data from South Africa now provide important insights into the differences in mesothelioma risk associated with different asbestos fiber-types. Three case series reports and one analytical report were reviewed in this session. In total, information on 504 proven cases was presented. There were 28% of cases arising from occupational exposure in mining, 35% from non-mining occupations, 23% from environmental exposures; 14% where no exposure was established and 9% where the exposure was unknown. Among the 129 cases for which occupational exposure and asbestos fiber-type were established, 115 cases were associated with occupational exposure to Cape crocidolite; 1 case associated with occupational exposure to Transvaal crocidolite and 9 cases with occupational exposure to amosite (grunerite asbestos) and 4 cases with occupational exposure to mixed fiber-types. There were no cases associated with chrysotile asbestos. There were 33 cases of environmental mesothelioma linked to Cape crocidolite exposure and 2 to exposure to amosite and crocidolite but none to Transvaal amosite alone or to chrysotile. The evidence shows that amosite is capable of causing mesothelioma but that the major risk in South Africa is associated with Cape crocidolite.

Jan 1, 2008

By Changjiang Li, Jun Yang, Qiang Fu, Xu Chang, Xing Wu, Yubing Gao

With the development of underground mining, the deformation of roadway floor has increasingly become a major constraint on the safe and efficient production of coal mines. To address the floor deformation that was caused by massive stress concentration in roadway, an innovative method based on deep-hole directional tensile blasting technology is put forward. By taking No.122108 working face in Caojiatan Coal Mine as engineering background and analyzing the mechanism of deformation, a numerical simulation and field test are carried out to verify the effect on deformation control of this technology. It is found that the deep-hole directional tensile blasting technology can actively control the fracture position of the roof in the gob area and cut off the stress transmission path, so as to relieve the stress in the roadway. And since different blasting parameters have different impacts on the stress relief effect, a numerical simulation is implemented and it is found that the stress relief effect is the best when blasting depth is set to be 32 m and the blasting angle be 60°. By applying the optimal blasting parameters to the field engineering test, it can be seen that the deep-hole directional tensile blasting technology could effectively reduce maximum stress value and stress field range of the both sides of the roadway, and make the stress field far away from the roadway, thus effectively controlling the deformation of the roadway floor. The deep-hole directional tensile blasting technology can effectively solve the problem of roadway floor deformation and can be safely applied to engineering sites.

Jun 13, 2023

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 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 Belar,2 by von dem Borne,3 by Benndorf4 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 (McCollum 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, 1928

By D. W. Heard

Electrospark Deposition (ESD) is a low heat-input, high energy density, micro-welding process. The short pulse duration and high-pulse frequency, in combination with the small amount of material transferred during each pulse, results in the evolution of extremely rapid cooling rates, believed to approach 105-106 °C/s [1]. This rapid solidification event results in the refinement of the microstructure to the nanostructured or amorphous level [2, 3]. Figure 1 displays the resultant microstructure of an Al-17%Si alloy deposited by the ESD process. Furthermore, it was determined that the microstructure of the deposit remained unchanged after subsequent layers were welded onto the presented layer. Freeforming of materials is a rapid prototyping process in which the deposited feedstock is built-up to the desired geometry in a near-net shape manner. Figure 2 displays the automated set-up employed produce three dimensional freeformed objects via multiple deposition trials of the ESD process. The automated XYZ table is equipped with CNC software to transform CAD renderings into three dimensional tool paths. Figure 3 displays an Al-12Si freeformed gear (2" diameter, 12 teeth) produced by the ESD process, prior to removal from the substrate. An SEM analysis of the freeformed component showed that the microstructure did not coarsen during the deposition of subsequent layers during the freeforming process, as depicted in Figure 4, resulting in the production of a bulk nanostructured component. This paper represents a summary of the capabilities of ESD to fabricate advanced materials possessing refined microstructure. In particular, results on the microstructural evolution obtainable for various wear-related systems will be presented. In addition, the feasibility of using the ESD process to freeform three-dimensional objects via multiple deposition passes will be presented and accompanied by a characterization of the properties of the freeformed component. [1] R. N. Johnson, "ElectroSpark Deposition: Principles and Applications," in Society of Vacuum Coaters, 2002, pp. 87-92. [2] J. Milligan, D. W. Heard, and M. Brochu, "Formation of nanostructured weldments in the Al-Si system using electrospark welding," Applied Surface Science, vol. 256, pp. 4009-4016. [3] S. Cadney and M. Brochu, "Formation of amorphous Zr41.2Ti13.8NilOCul2.5Be22.5 coatings via the ElectroSpark Deposition process," Intermetallics, vol. 16, pp. 518-523, 2008.

Jan 1, 2010

By Anders Sellgren, K. Hansson, A. Jedborn

In the mining industry, conversion of fine particles into a slurry is often part of the normal processing of the ore. Therefore. from a system's point of view, slurry transportation would be considered as a natural alternative, all the way from the working face to the final processing. In underground mines, there is sometimes a considerable inflow of ground water that has to be pumped out. When the mine dewatering installations are integrated with a hydraulic hoisting system, the cost of power needed to pump out the ground water can be excluded from the cost of hoisting, compared with other modes of transporting the solids to the surface. The chief advantage of hydraulic hoisting is that the hoisting capacity can be increased at comparatively low total cost without necessitating the sinking of new shafts. Alternative examples include deepening of the existing mechanical hoisting system, truck, or conveyor belts transport in ramps to the present level. These often become very expensive. The economic effectiveness of hydraulic hoisting and hydraulic design considerations have been discussed by Kostuik (1965) and Sellgren (1985, 1986) for both small shallow mines and large deep underground mines. Objective and scope The objective of this study was to demonstrate the feasibiliy of hydraulic hoisting in hypothetical examples of mine deepening. Underground grinding to a maximum particle size of about 700 um (about 25 mesh) is considered. The pumping of ground ore products with positive displacement plunger or membrane type of pumps at working pressures of up to 15 MPa (2200 psi) is a thoroughly tested technique (Venton, 1986). Hydraulic hoisting system A hydraulic hoisting system is described schematically in Fig. 1. The ore is mined, handled, and crushed conventionally. It is then ground wet underground. The slurry is then temporarily stored in an agitated tank and pumped to an agitated receiving tank on the surface. The ore is then further processed in the concentrator. The capacity of a pipeline is very high. For example, an annual production of 500 Kt (550,000 st) of ore can be handled in a 100-mm-diam (4-in.-diam) pipeline. Systems layout - economic effectiveness Schematic mine layouts are presented that represent situations where hydraulic hoisting often is the most economical alternative. A situation where the ore is trucked to the level of the existing hoisting system is shown in Fig. 2 (following page). With hydraulic hoisting, only a shaft for ventilation, pipe- line, and personnel are needed. In a first phase (Fig. 2). a hydraulic hoisting installation with crushing and grinding units, storage facilities, and pumps has been located at a level of about 400 to 600 m (1310 to 1970 ft) below the surface. With further development of the mine, the hydraulic hoisting

Jan 1, 1990

By M. M. Rajkovich, J. J. Zaluski, S. J. Gardner

The telephone rings at 3:20 a.m. and an exasperated voice on the other end says, “There’s been a mine explosion at Mine No. 5 and we have not heard from three units of men!” Twenty-three minutes later, the phone rings again and another panicked voice says, “There’s something wrong at the slurry impoundment, the pool level has just dropped five feet and we’re trying to figure out what’s wrong!” Thirty minutes later, the mobile phone rings and an excited security guard says, “We have reports of thick black water running down both the right fork and left fork of Straight Creek and both seem to be rising in the banks!” As if this isn’t enough excitement, the mobile phone rings again and a stressed company official says, “I just heard a report that black slurry is running out of the portals of XYZ Company No. 2 Mine, which is adjacent to our No. 5 Mine!” Is this all some kind of dream or nightmare? More importantly, however, if this could happen, what on earth do you do? Although we all like to think that “It can’t happen to me,” we all must admit that mine explosions do happen, slurry impoundments can rupture and creeks can flood with black water causing damage to others, including competitors. Your response must be quick, cool-headed, calculated and effective. This paper will examine the issues, concerns and ramifications of this hypothetical “disaster” and then present a systematic crisis management response. While each situation is different, there are general guidelines for forming an effective plan of action.

Jan 1, 2003

By Ren G. Dong, Dan E. Welcome

Instrumented handles or dynamometers are widely used to measure hand forces and/or the biodynamic response of hand-arm system. To study hand-transmitted vibration exposure, six generations of instrument handles were constructed or initially developed by researchers in ECTB/HELD/NIOSH. This presentation provided a summary of these handles. Their basic characteristics, limitations, and usefulness are described, which may help their appropriate applications and further improvements. Six Designs of Instrumented Handles Handle 1: The conceptual design is recommended in ISO 10819 (1996)1 for glove test. The grip force is measured by detecting bending strains on a measuring beam in the handle. A special handle fixture was designed to connect the handle to a shaker. Except the screws, the handle and fixture were made from aluminum. Handle 2: The design is based on the principle of shear strain measurement.2-3 Both grip and push forces can be measured simultaneously using this handle. This handle was directly designed for a simulated vibrating tool. Handle 3: This design is basically composed of a handle base, a measuring cap, and two charge-based sensors (Kistler 9212) sandwiched between the base and cap. The handle was also made from aluminum. The fixture for Handle 1 was also used with this handle. This generation of handle has three different handle diameters (30, 40, and 50mm).4 Handle 4: This design is an improvement from Handle 3. The handle fixture was totally redesigned and it was much stiffer than the previous one. The aluminum measuring cap was replaced with a magnesium cap. Handle 5: The basic structure of this handle is the same as that for Handle 3. However, the piezoelectric sensors were replaced with two strain gage based sensors (Interface SML-50). Handle 6: This handle includes two measuring caps, four piezoelectric sensors, and a handle centre base. The handle fixture was the same as that with Handle 4. Methods for Handle Examinations The static and dynamic characterizations were performed using the methods reported by Dong et al.5-6 Results and Discussion Handle 1: The static force measurement depended on the hand grip location on the handle. Its natural frequency was less than 200 Hz.5,6 Because the transmissibility of gloves may not vary significantly with the applied grip force, this handle may be acceptable for glove test. However, the force measurements with this handle may not be reliable. Handle 2: The static force measured with this handle was insensitive to the hand acting location. However, when the handle was vibrating, the force signals could be totally distorted. For this reason, it was not used for vibration studies.

Jan 6, 2006

Laboratory scale simulation experiments show that the adsorption capacity of Au(CN)Z- on activated carbon in the presence of organic plant contaminants is dependent on the particle size of the carbon. This observation suggests that fine carbon in a CIP contactor can protect coarse CIP carbon from fouling in a dirty CIP plant. A preliminary test of this concept was made using fine lignite coal as the organic scavenger in the presence of the CIP carbon Calgon GRC22 in an alkaline cyanide solution containing Teric 401, sodium ethyl xanthate and kerosene.

Jan 1, 1991