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By Jorgen Elbrond

Before and in the early stages of industrialization, mining was the undisputed leader in technology. It represented the high-tech of the time. Early mechanization bears witness to that. Hoisting and rock breaking driven by waterpower are such examples. The mines' use of the steam engine was a major incentive to its development. By these means new mines could be opened and more metal supplied. Understanding of systems was essential for miners when shaping the infrastructure of the mines for the transportation of ore, material and men and for the evacuation of water and for ventilation. The irrigation systems of ancient mines are such examples. However, with the industrial revolution other more specialized branches of industry advanced further, and the mines became users of other industrial branches technologies. The mining industry had, however, always been quick to recognize a good thing and use it, when time was right. But, compared with other branches of industry, the mining industry has the disadvantage of working in a rugged environment with (and actually inside) a raw material which is abrasive and highly variable with respect to mechanical properties. This determines the rather high unpredictability of mining machines' performances and their low availabilities and explains a part of the delays in introducing technological advances.

Jan 1, 1989

High-type research metallurgist with approximately following qualifications: American, 30 to 45 years old. Mind-Analytical. Education-college graduate. Practical shop experience-not less than 5 years. Metallurgical experience in steel making-at least 5 years. Chemical experience-should have some chemical training. Research ability -should be the type of man who is interested in new developments or research work. No. 337. Engineer with some underground, experience who is physically able to spend a large portion of his time underground, to act as general efficiency engineer. He will have cost keeping on special work, charge of contracts, labor distribution, etc. No. 338. The services of a man experienced in flotation and familiar with the Callow apparatus are required for a short engagement in South America. No. 339. A position as surveyor and draftsman for mines in Mexico is open. Opportunity for advancement. Climate pleasant and healthful. Knowledge of Spanish required. No. 340. The Bureau of Construction and Repair, Navy Department, Washington; D. C., is in need of a few draftsmen of experience for work in connection with the development of industrial yards and shops of the Navy, under the cognizance of the Shore Establishment Division of the Bureau of Construction and Repair. Training in one of the following courses would be considered a requisite qualification:

Jan 9, 1918

Blast furnace slags which fall into the quaternary system SiO2 - A1203 - MgO - CaO have latent hydraulic properties which depend on the degree of vitrification. When the oxides com- bine to form Calcium Silicate Hydrates and other products of hydration the bonds between elements are at a lower energy level than those which exist in the glassy state. Transition from the glassy state to the crystalline state is thermo- dynamically favoured and, in the context of this paper, such slags possess internal energy. Manufacture of Portland cement is respon- sible for about 3.6 per cent of total industrial energy consumption in Canada. Pyroprocessing accounts for about 83 per cent of this figure or 3 per cent of the total. The processing of blast furnace slag to a condition in which it can be used as a partial substitute for Portland cement requires no pyroprocessing and, on average, only about 11 per cent of the energy needed for Portland cement. In North America the benefits of slag as a cementitious materials have been obscured by other considerations, the most important being commercial strategy. This situation has under- gone radical change as a result of the rising cost of energy, and government pressures to conserve energy.

Jan 1, 1979

By L. Russell Payne

The use of shock tube in the blasting industry is relatively well characterized and understood within the realms to which it is used. Non-conventional uses of shock tube within the EOD and the Aerospace Industry however has not been as widely researched and published. Characteristics of shock tube such as its reliability, simplicity and its non-electric nature make it ideal for functioning or driving mechanical mechanisms, detonators, and timing devices. Outlined in the text are the performance characteristics of shock tube in an array of atmospheric environments including pressures ranging from ambient to 100,000 ft equivalent atmosphere. In addition the useful exit work energy or impulse of the shock tube for driving these various EOD and Aerospace mechanisms is published as a function of tube lengths and atmospheric pressures. Of particular interest to these devices is the required length of shock tube needed to produce the steady state detonation energies and the accompanying properties of the shock tube at these lengths. Various sources publish an arbitrary run distance for steady state detonation and output some where between 20 cm and 1.0 meter. Statistical and experimental evidence with in the text show these numbers to be low and provides an updated reference for shock tubes usage in nonconventional situations.

Jan 1, 2008

By Marcel Laflamme

Underground mine workers are continuously exposed to many sources of noise and vibration in carrying out their tasks. Even though the vibration and sound level of some mining equipment is documented, it was found that this information is not readily available for many pieces of equipment and that it is not considered when choosing equipment or planning tasks. As well, health problems related to vibration and noise are among the main causes of work-related compensations in mines. Considering those facts and although no Canadian regulations could force employers to limit the exposure of their workers to vibration, the Société de recherche et développement minier (SOREDEM) decided to address the problem by including vibration among their research priorities. In order to characterize noise and vibration sources of different mining equipment used for underground mining, the authors have performed a study in 8 different mines in Québec on 28 different mining equipments. The paper will present the procedure that was followed to select the list of equipment to be evaluated and the low cost acquisition system developed to perform multichannel time domain acquisition in harsh environments. It will also present the results obtained for the noise level produced by the equipment as well as for the hand-arm and whole-body vibration exposures.

Aug 1, 2013

By J. F. Shirley

"Very seldom, if ever, is a molybdenite by-product plant operated exactly the way the process design engineer visualizes it. The best thing the design engineer can do is provide a sound, basic circuit with enough room and flexibility in order that the operating staff can make the necessary modi fi cations to optimize the process. The plant, with minor modifications, should be capable of handling more than one process. This is especially true when the client is having the plant designed for a new process.The writer would like to propose the following ten ""rules-of thumb"" for designing by-product molybdenite plants where the molybdenite is floated out of a copper concentrate. The term rules-of-thumb is used, because there are probably valid reasons for not using one or more of them in a particular plant design. In fact it was 1980 before the writer was all owed to start up a plant where all of these rules were honored in the plant design. This was after 19 years of experience in the design of molybdenite by-product processes and plants. The main reasons for not following the rules are available capital, available space, and the client's experiences based on pilot plant and laboratory test results."

Jan 1, 1981

H. G. Haemers (Ghent University, Belgium)—The authors claimed "the results of their work indicate that the metals can be arranged in a sulfation series similar in its application for selective sulfation tot the electromotive series for displacement of metals from solution". The series as stated in decreasing order for tendency of SO3 give up, is the same as that stated by free energy diagrams. Indeed, the degree of stability of a sulfate is measured by the free energy of sulfate formation out of the corresponding metal oxide and SO3. The more negative the value of the free energy (-DG) the greater the stability of the sulfate. As a second consequence this statement results in a relative aptitude for capture of SO3 by each metal oxide when brought in contact with the sulfate of other metals. Let M1 and M1 be the two metals, and — DG1 and — DG2 their free energy values at temperature T. Both sulfates are stable at temperature T if - DG1 < O and — DG2 < O. In case where — DG1 < — DG2 the stability of M1SO4 is greater than that of M2SO4, and when M1O (oxide of

Jan 1, 1958

By A. G. Crocker

The positions of twin reflections in electron-dijjcraction patterns obtained from thin metal foils may he calculated for any twin in any crystal structure by means of an elementary application of vector algebra, General equations for the four classical orientation relationships are presented using the superscript and subscript notation of the tensor calculus, which is briefly described. As an example of the application of these expressions, the case of twinned rhomhohedral crystals, and hence as a special cased twinned cubic crystals, is examined. CONSIDERABLE interest has recently been shown in the interpretation of electron-diffraction patterns obtained from twinned regions of thin metal foils. In the present paper, it is shown that the necessary information may be obtained directly for all twins in any crystal structure by means of a very elementary application of vector algebra. The equations involved are most conveniently presented by making use of the very powerful superscript and subscript notation of the tensor calculus. The use of this notation will first be described and then applied to the problem of calculating diffraction patterns for any twinned crystal. Finally, as an example of the application of the method, the specific case of twinned rhombohedra1 crystals will be considered.

Jan 1, 1965

During development mining, ventilation capacity may decrease and the ventilation requirements may depart from initially planned values depending on the mining rate, increases in the methane emission rate, and changes in ventilation airway leakages. Insufficient ventilation air quantities and the occurrences of high methane liberation rates can overwhelm the existing quantity of ventilation air and result in elevated levels of methane gas during development mining. This condition can both limit the development of that section and increase the risk for an ignition that may lead to an explosion. Thus, the prediction of ventilation air requirements prior to mining can enhance worker safety by reducing the likelihood that explosive methane-air mixtures form. This study presents an approach for prediction of methane inflow rates using coalbed methane reservoir modeling. For this purpose, a two-phase coalbed reservoir model of a three-entry type roadway is developed. In the model, grids are dynamically controlled to simulate development of entries. Examples are given for methane inflow and ventilation air requirements as a function of mining rate, development section length, mining height, and the existence of degasification boreholes. This technology can be used to limit the methane concentrations occurring as a result of the influences of various coalbed and operational parameters.

Jan 1, 2008

By K. Koizumf, A. A. Cram, K. Whitchurch

The Expert Scheduling is a new, exciting method for scheduling underground and open-cut coal mines. A key feature of the Expert Scheduler is the adoption of an expert or artificial intelligence system. The expert system makes decisions regarding the schedule, such as which area should be mined. With existing scheduling systems these choices are made by the scheduling engineer. Developing one area may be better than another if it offers better quality or lower costs. Information the engineer considers in these decisions could be; • coal tonnage and quality targets, • equipment utilisation, • mining cost, • and other practical constraints. In expert scheduling a number of experts are appointed to make these decisions. A number of mining strategies are examined for each period. Information for each strategy is evaluated by "experts" and the "best" solution adopted. The method is based on the Blackboard Techniques. With this technique information is presented to "knowledge sources” or "experts" by the Blackboard Controller for their "opinions". These "opinions" are examined by the Blackboard Controller to select the best strategy. Engineers can readily add experts to the system, and modify the weighting of experts to suit mining conditions. Using an Expert Scheduler means that many schedule op- tions can be analysed quickly with full repeatability.

Jan 1, 1996

By Rudolf Greuer, Gerald Jalkanen, Huann-Sheng Chen

A short cut is presented where the average grade above a primary grade cutoff and its associated byproduct grade(s) are estimated by screening the primary and byproduct grades. For the primary variable, choose samples whose grades are above a cutoff of interest. Compute variograms for the subset of the primary variable. Then using this variogram, krige the blocks of interest only using the samples whose grades are above the cutoff. The next step is to screen byproduct grades by choosing byproduct samples whose associated primary grades are above the cutoff of interest. Next compute variograms for this subset of byproduct samples. Then using this variogram, krige the blocks of interest using byproduct sample grades whose associated primary sample grades are above the cutoff of interest. The results are the average grade above a primary cutoff for both the primary and the associated byproduct variables. Using two simulated primary and reference data sets a case study resulted in the screening krigings performing better than the indicator kriging approach in the first case study. A second case study had mixed results with the primary indicator approach performing better than the primary screened approach. The byproduct screened approach performed better than the byproduct indicator approach.

Jan 1, 2002

By Philip L. Collyer

A technique for evaluating the similarity of ore deposits is presented. A Q-mode cluster analysis is performed using information on tungsten mines in North America. This is a method of grouping several samples according to their similarity based on a simple matching coefficient. Tungsten mines are grouped or clustered on the basis of geologic variables. It is possible to interpret and evaluate different ore environments according to age, mineralogy, and other variables. It is well known that variable geologic conditions influence the occurrence of certain types of minerals. If one variable is responsible and identified, that variable can be searched for in exploration. If several interrelated variables are responsible for forming a favorable environment, then recognition and identification may be more difficult or completely masked. Therefore it is helpful in exporation to isolate and identify multiple interrelated variables which control the localization of mineral deposits. Cluster analysis is useful in mineral exploration where considerable amounts of data are available for analysis. Subtle relationships that might be overlooked because the data are voluminous can be isolated using this technique. Cluster analysis can be used to establish exploration prioriy in unknown areas on the basis of similarities to known metallogenetic provinces.

Jan 1, 1976

By Linn M. Farish

The estimated production of petroleum in the Dominion of Canada for 1931 was 1,582,000 bbl., an increase of 60,000 bbl. over 1930. Nearly all of the production came from Alberta, with a small quantity from Ontario, and a very minor amount reported from New Brunswick. At the beginning of 1931 it was hoped, and predicted, that a substantial increase in production would be shown for that year, but such was not the case, since Alberta did not show the anticipated gain. The production from Ontario and New Brunswick has not varied more than a few thousand barrels during the past 10 years and aggregated 124,000 bbl. in 1930, with 126,600 bbl. estimated for 1931. Unless new fields are discovered, production in 1932 will decline, with Ontario and New Brunswick showing little change and Alberta declining appreciably. Canadian production by provinces during the past 10 years is given in Table 1. Furnished by the Dominion Bureau of Statistics. a Barrels of 35 Imperial gallons or 42 U. S. gallons. c Figures for Ontario and New Brunswick are estimated. The production of natural gas in Canada reached the record figure of 29,377,000,000 cu. ft. in 1930 and it is estimated at 26,874,600,000

Jan 1, 1932

By Thomas J. Regan

The first stage of the Massachusetts Bay Transportation Authority&apos;s Red Line Extension Northwest, is a two-track rapid transit extension from Harvard Square in Cambridge, through three stations, to the Alewife Station/Garage complex in North Cambridge. The extension, about 5.0 km. (3.1 miles) in length, is entirely in tunnel, with the Alewife Station/Garage complex and adjacent line sections of tunnel constructed by cut-and-cover methods. The Station/Garage complex, just west of Alewife Brook Parkway, is in an area underlain by deep deposits of very soft highly sensitive clays. It is proposed to construct the station and adjacent tunnel sections by the slurry trench method, using the slurry wall as the permanent structural wall of the station and tunnel. The unusual nature of the underlying clay and its very high sensitivity raised questions concerning the feasibility of the proposed construction. Since research failed to reveal any construction precedent for the specific conditions encountered, a test section was undertaken to determine construction problems, resolve uncertainties, and to establish acceptable parameters for the construction of the slurry walls. PROJECT ORGANIZATION Sverdrup & Parcel as tunnel and transit systems consultant for the Red Line Extension-Davis Square to Alewife had overall responsibility for determining program objectives, project management and test implementation.

Jan 1, 1979

By W. F. Laverty

Two recent papers in this journal1,2 contain experimental evidence for an anomaly in the concentration gradient for tracer diffusion. In both papers, the authors suggest that this anomaly is due to a Gibbs&apos; absorption effect. Their hypothesis is that surface active tracer elements tend to remain in or near the surface adsorption layer, thereby altering the diffusion flux and concentration gradient. It is not clear how the anomaly can be explained in terms of an adsorption effect. Surface tension forces act parallel rather than perpendicular to a surface and therefore should affect only the rate of spreading of surface active agents tangentially across a surface. Frenkel3 has given a short treatment of surface tension as a driving force for surface diffusion. While the equilibrium concentration of a surface active agent at the surface of a solution is known to be higher than in the bulk, its chemical potential is necessarily the same. It is difficult to see how adsorption can result in an anomaly in the chemical potential gradient, which is the driving force for diffusion. A more detailed explanation by the authors of the adsorption mechanism is in order. A similar anomaly does not seem to arise where

Jan 1, 1970

By W. E. Horst

Raw materials and mineral products are crushed, ground, or pulverized for a variety of reasons. Some of the most important reasons for size reduction are: to liberate marketable mineral species from a matrix of commercial minerals and gangue, to promote rapid chemical reaction through exposure of large surface area, and to produce a material with desirable size characteristics for handling, utilization, and storage. Comminution processes are currently used on vast tonnages of raw material annually. In the mineral industries where mineral products and other solids are processed, the various size-reduction unit operations represent a major portion of the manufacturing costs. The comminution process is an expensive unit operation from the stand- point of both capital and operating costs. Power consumption is large, and the energy conversion to useful work is very small regardless of the size-reduction system. In energy terms, about 1% of the all electricity generated throughout the world is expended in crushing and grinding operations by the cement industry alone. Comminution is a general term for size reduction that may be applied without regard to the actual breakage mechanism involved. General type of size-reduction equipment include crushers, tumbling mills of various type, impact mills, fixed-path mills such as a roller mill, and fluid-energy mills. Some comminution machines accomplish

Jan 1, 1985

When a joint venture is established between a major and a minor, the co-venturers often have a number of divergent interests; the major may have put up significantly more capital into the project and will want to protect its investement; the major may have more financial resources and be more readily to commit capital to the project; the major may have more technical resources and expertise to provide to the project; the major may have other competing demands for its capital; the minor may be relying on rapid development of the project as its sole source of cash flow. Successful joint ventures arise when the co-venturers understand each others&apos; interests and attempt to satisfy these interests. This could be achived by having a clear process and timetable for development of the project coupled with clear rules for distribution of income, the commitment of capital to the project and the provision of inter-company services. If divergent interests are either regulated clearly or eliminated, both co-venturers are more likely to seek common objectives in the joint venture with less scope for conflict. This paper, written from the perspective of a major, examines means of establishing successful joint ventures between majors and minors.

Jan 1, 1997

By Vladimir Adamek

This paper describes the Bureau of Mines development of a novel subsidence prediction methodology suitable to the mining and geologic conditions in the Northern Appalachian Coal Region. It describes the computation of vertical and horizontal movements, inclination, curvature, and horizontal strains. The substance of this method is the separation of the effects of lithology by introducing a correlation between hypothetically homogeneous overburden and existing lithologic conditions, while providing for different mining conditions, i.e., underground geometry and overburden thickness. The effects of lithology have been expressed in the form of a variable subsidence coefficient within the subsidence trough. The subsidence coefficient is considered a constant for other predictive methods. Field data from 16 test sites at 11 Bureau longwall panel studies were used in the analysis. For each panel, the characteristics of the variability of the subsidence coefficient were defined. Regression analysis of the subsidence coefficients from all test sites on their locations relative to the edges of their respective panels yielded a third-degree polynomial equation. The results from additional longwall panel studies, not included in the regression analysis, were used to prove the validity of this method. To facilitate the use of this precalculation methodology, a computer program was written in BASIC for use on a personal computer.

Jan 1, 1987

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

4. Preliminary Study - Remote Seal Checker 4.1 Introduction Determination of the completeness of each individual seal at the time of its emplacement is essential for an effective remote sealing system. A satisfactory seal checking technique should provide a signal which: (1) indicates percentage completion as the seal is emplaced (2) provides a definite indication of a complete seal (3) indicates the size of the unsealed area if a complete seal is not feasible This information is required to establish the need for additional seal material, the need for additional seals, and the risk likely involved in entering the mine., In many situations it is as important to know the quality of a seal as it is to build an effective one. It is likely that with repeated use the remote sealing technique developed by Foster-Miller Associates will be sufficiently reliable and predictable to preclude the seal checking requirement. It is recommended, however, that each seal be checked during construction to insure its completeness and increase the level of confidence so necessary in reopening the mine. 4.2 Description of General Problem Several characteristics of remote mine seals are important in considering techniques for evaluating the effectiveness of these seals. These include:

Jan 1, 1973

By Donald W. Mitchell, John Nagy, Edwin M. Murphy

In 1957 research was initiated in the U.S. Bureau of Mines experimental coal mine near Pittsburgh, Pa., to study factors affecting foam generation and transport, to evaluate the effectiveness of high-expansion foam for controlling mine fires, and to develop techniques for applying the method under U.S. mining conditions. These investigations showed that high-expansion foam containing at least 0.2 oz of water per cu ft of foam is effective in controlling experimental underground fires burning coal, wood, and oil. Sometimes the fire was completely extinguished, but more often, it was brought under sufficient control to permit either a direct attack on the fire with a stream of water or loading of the hot material into cars. A progress report prepared in July 1958 summarized the initial achievements of the USBM experiments. Since then other phases of the foam-plug method for attacking fires have been studied in the laboratory and in the mine. Previous studies by British engineers of the foam-plug method for fighting mine fires indicated that high-expansion foam was effective in controlling experimental timber fires in an underground passageway. Their subsequent work pertained to the practical aspects of fighting large fires within a mining area with a foam-plug.

Jan 9, 1960