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By T. J. Fee

Introduction The International Nickel Company have been pioneers in mine rescue work in Ontario. Following the fire in the Hollinger mine in the spring of 1928, the Company purchased ten self-contained oxygen breathing outfits, ten all-service gas masks, an oxygen high-pressure pump, life line, inhalator, ten cap-lamps with batteries, and a complete stock of spare and accessory parts. An instructor from the U.S. Bureau of Mines, Pittsburgh, came to the Creighton mine for one week and trained twenty men in the use and limitations of all equipment. Monthly training courses were commenced in the fall, and have continued to the present time. Of the original twenty men trained, ten are still on the Creighton mine rescue teams. In the meantime, and as an aftermath of the Hollinger fire, the Work-men's Compensation Board of Ontario and the Ontario Department of Mines established a central mine rescue station at Timmins. This was completed in the spring of 1930. It was then decided, in view of the great expansion in mine development in the Sudbury district, to build and equip a similar station to serve all the mines there, namely, Creighton, Frood, Garson, Falconbridge, Sudbury Basin, and Errington. An extensive survey was made and a central location selected opposite the Frood mine. The International Nickel Company donated a site, and the station was completed in the fall of 1930. The station is a two-storey brick building, 27 ft. by 47 ft., with a large garage adjoining it. The ground floor is used for equipment and for training the crews. On the second floor are living quarters for the superintendent and his family. The garage houses a closed truck, in which all necessary equipment can be taken to any desired point for training purposes or for actual mine rescue work, if and when necessary. The garage is also used as a gas room, where the men are trained in an irrespirable atmosphere. A gas-tight observation window between it and the training room enables the superintendent to see and direct the men undergoing training, weight exercisers and other devices being used.

Jan 1, 1935

By K. Yoshida

Recently, light magnesium alloy with superior heat radiating ability has been attracting attention in various fields. However cold plastic working of the alloy is very difficult and hot working necessary. Furthermore, the magnesium of products with complicated shapes is difficult, the processing cost is high, and the applicability of the alloy is limited. In this study, a technique for obtaining fine wires and tubes by cold drawing is examined to obtain wires and tubes with high strength, quality and surface morphology, while decreasing production cost. In addition, the shearing strain of magnesium alloy wires and tubes drawn under various drawing conditions was calculated by FEM analysis. It was clarified that cold drawing of magnesium alloy is possible. It was also demonstrated that greater reduction of the cross-sectional area could be realized during cold wire and tube drawing by optimizing the drawing conditions.

Jan 1, 2006

Jan 1, 1959

By K. B. Chaudhurl

The thermodynamics of the reactions taking place are examined with the aid of equilibrium diagrams for the Pb-O-S system. Based on investigations of chemical, mineralogical and differential-thermo analyses of intermediate products of different desulphuration degrees, an attempt is made to explain the mechanisms of the reactions in the smelting shaft of the KIVCET furnace. The differences between this and other direct lead smelting processes are demonstrated by these thermodynamic and kinetic considerations. Proceeding from these results, the practicability of direct lead smelting processes is discussed with reference to the composition of the primary feed materials to be processed. This comparison also considers the behaviour of minor metals, the products obtained and their characteristics in respect to further treatment. For assessing the operating costs, the over-all energy consumption is considered taking into account various price relations between electric energy and fuels/reductants. Based on the peculiarities of the various processes, an attempt is made to compare the necessary means of meeting the pollution control requirements. The paper concludes with reference to the criteria and problems involved in comparable evaluations.

Jan 1, 1978

Every text book for blasting in Japan says that Hauser's law can be applied for practice. But recently it came true that there was no historical record about him and no actual datum of his own or other's to testify. According to his theory, the funnel ratio N = r/W in crater test is inversely proportional to the rock strength and proportional to the explosive amount: where r is the radius of crater and W is the burden. But experiment showed the opposite result, and revealed new information. Two kinds of experiment, crater test and boulder blasting of mortar, were carried out to investigate the effects of rock properties on blasting. The material used for test 1 and test 2 was a mortar block (60cm)3 cube, 4 vertical faces of which were used for crater test. The results from Test 1 and test 2 were summarized as follows. The funnel ratio ranges between 2.5 to 4.5 in proportion to rock strength and burden. The standard ratio of 1, reported by Hauser, was not observed in any instances. It was also noted that the funnel ratio is independent of the explosive amount. The material used for boulder blasting, test 3, was a mortar block (40cm)3 cube, in the middle of which was located a vertical borehole for the explosive charge. The results of test 3 were as follows. The necessary explosive amount for boulder blasting is in inverse proportion to the mortar strength. Fragmentation and throw are proportional to the mortar strength.

Jan 1, 1990

By John D. Weibmer

A remarkably simple construction system that derives its internal stability from metal straps buried in backfill is finding diverse mine applications, ranging from rock crusher headwalls to massive slot coal storage facilities. Reinforced Earth (Re/Earth), the system trade name of Reinforced Earth Co., is proving itself 20-50% less expensive than alternative earth embankment structures, and in the case of cast-in-place concrete walls, six to seven times faster to erect. While the majority of applications are in the realm of civil engineering-projects such as retaining walls, bridge abutments, slide buttresses, and containment dikes-a growing proportion is mine related. Of the estimated 120 Reinforced Earth projects that will be completed this year, company president David P. McKittrick expects mining to account for about 20% of the business volume.

Jan 8, 1978

The BHP Steel Group embarked on a Total Quality Control (TQC) programme in 1984 in response to enquiries from a major customer regarding procedures for quality in materials supply.The TQC initiative has been adopted by all seven Divisions of the Steel Group and covers a broad and comprehensive range of management and workforce improvement initiatives.The development of the TQC initiative in the Collieries Division of BHP Steel over the past eighteen months has resulted in important experiences and leanings.

Jan 1, 1991

The mineralogy of regolith material for which whole rock geochemistry has already been done can be used to better understand/rank the significance of geochemical anomalies. Case studies show that the secondary minerals of the regolith environment have quite different capacities to incorporate pathfinder and target elements, eg hematite appears to be a better host to Pb than goethite and Pb rich alunite-jarosite minerals are a better Ag host than mimetite. Thus correlations between elements in regolith material may be strongly affected by mineralogy. Understanding of the significance of a geochemical anomaly is frequently enhanced by knowledge of the weathering susceptibility of different minerals. For example, when a mineralogical sequence which does not correspond to the expected order is found (eg feldspar overlying weathered material without feldspars) it is possible that transported material is present in the profile. Such mineralogical information is particularly relevant as exploration continues into areas of thick regolith.

Jan 1, 1997

By M. J. Beus

A shaft is truly the "lifelinen of an underground mine. Damage to the shaft lining and guides as a result of ground movement can result in serious loss of production and extensive and continual repair. In some mining districts, annual shaft repair and maintenance costs resulting from high rock stresses and excessive displacement are in the millions of dollars per year. For many years, the Bureau of Mines has conducted research to characterize the rock mass and to develop structural guidelines to improve the design of accessways in deep mines. Much of this work has centered on determining the in situ conditions that affect the structural stability of shafts in the Coeur d'Alene Mining District of northern Idaho. Recent work by Beus and Board (1984) has concentrated on measuring the rock and support behavior during sinking of the Silver Shaft at the Lucky Friday Mine. These results are currently being used as a comparative data base for further basic research as well as to establish structural design criteria. The factors affecting the deign and structural stability of deep mine shafts are numerous. A design approach that use field data as input and directly compares field measurements with numerical models can validate the procedure and provide realistic design criteria. Naturally occurring "fixed? conditions such as magnitude, direction, and ratio of in situ stresses, geologic environment, and physical properties and constitutive relationships of the rock mass ere obviously basic to numerical modeling.

Jan 1, 1989

By Richard Brink, Eric M. Klein, Kenneth B. Andromalos

"A portion of the roof for a 129 x 144-inch, nearly 100-year-old sewer outfall in the City of Baltimore had deteriorated to the point that it resulted in the development of a large sinkhole in a residential neighborhood. A subsequent video inspection of the sewer outfall indicated that there was a hole in the sewer outfall, and it would need to be repaired . After initial backfilling of the sinkhole and repairs to the water service lines, a conventional wood shoring system was used to support the excavation and expose the Main Outfall Sewer to inspect and repair it. This excavation was unsuccessful because of loose sandy soils and high groundwater conditions. An innovative use of a steel reinforced jet grout excavation support system was ultimately used to underpin an adjacent 20-inch water main and other nearby utilities, and provide access to the top of the Main Outfall Sewer some 22 feet below the street surface to facilitate inspection and repair of the sewer. This excavation support system was also successfully utilized in the final repair of the sewer roof by serving as a buttress for the new roof system.1.0 IntroductionThe project site is located in a residential neighborhood with brick masonry row houses situated on the south side of Chase Street and a brick masonry church on the north side of the street. Figure 1 illustrates the location of the site. The City right of way is 65 feet wide, and the street is 40 feet curb to curb. The centerline of the Main Outfall Sewer runs parallel to and a few feet south from the centerline of the street. Other utilities running parallel to the street include a cast iron 20-inch water line built about 1910, a 24-inch terra cotta storm drain, a 6-inch terra cotta sanitary sewer, a 4-inch cast iron gas line and a 40-inch electrical duct. Cross utilities included a 4-inch gas line and several smaller water and gas service lines to the church and row houses. One gas line that was not shown in the City's GIS database was exposed during the excavation."

Jan 1, 2005

By H. M. Myers, J. E. Funk

The two-phase flow of a drilling fluid in a diamond drill bit is investigated by deriving and solving the steady-state continuity and momentum equations. Parameters in this analysis are rotational speed of the bit, local rate of addition of drill solids, non-Newtonian nature of the drilling fluid and drilling rate. The describing equations relate the flow and pressure drop to the design characteristics of the bit. The equations are integrated numerically yielding the flow-rate pressure drop characteristics for the bit, flow distribution in the bit and velocity and static pressure as a function of position in each flow channel of the bit. Results are presented for a particular bit design. This paper shows that under normal drilling conditions certain parameters may be neglected in the hydraulic calculations for a diamond drill bit. Therefore, shortened forms of the equations presented can be used to fit the proper diamond bit to the drilling fluid hydraulic system. INTRODUCTION Like the conventional bit, the diamond drill bit is a key component in the circulating system of a well. The conventional rock bit is fitted to the circulating system by selecting the flow nozzles which provide the system with the proper flow-rate pressure drop relationship. Fluid behavior across the face of the diamond bit must be better understood so the bit can also be fitted to the circulating system. Data from field-operated diamond bits are presently available and do yield some information regarding the flow-rate pressure drop relationship. However, the number of factors affecting this relationship is quite large. Drilling parameters and conditions such as bit penetration rate, bit weight and rotational speed are important. Moreover, flow channels in the bit are part of the cutting head, and introducing drilled solids into the flow channels reduces the flow area, causes additional drag and influences the pressure drop. Many tests would have to be performed if field tests were required to study all parameters which might influence fluid behavior in the bit. A logical approach to this problem is to investigate analytically the fluid behavior in the bit, including parameters that are present under normal drilling operations. This approach, which seems to offer the best method for future studies, is presented in this paper. Following is the general procedure. 1. Equations describing the most general flow channel are written and include the addition of drilling solids (which is related to penetration rate), rotation of the bit, design parameters of the bit and non-Newtonian properties of the fluid. 2. A typical bit is designed and the bit parameters are substituted into the equations. 3. Parameters are assumed (penetration rate, rotational speed of the bit, mud weight, etc.). 4. The describing equations are numerically integrated to obtain the pressure drop across the face of the bit as a function of flow rate. 5. The pressure-drop contribution of each component (friction, acceleration, etc.) is obtained from the numerical solution, and those factors which largely influence the total pressure drop are identified. Classifying the drilling fluid is important in establishing the friction factor relationship since the frictional pressure losses are the main contributors to the total pressure drop. High-density drilling fluid is commonly assumed to be a Bingham plastic. 1-3 Govier4 presented a method for selecting a friction factor in the laminar flow region from the rheology properties of the mud and a modified Reynolds number. Metzner5 presented a criterion for selecting the friction factor in the turbulent flow region. The bit design used in conjunction with the solution of the equations has divergent flow channels. Stall, which is the backflow of fluid in the channels due to eddies that occur on the outer perimeter of the flow stream, can occur in these divergent channels (or diffusers). When stall does occur the static

By M. N. Brodie

"The ability to adjust the speed of a SAG mill offers benefits to the process and to equipment maintenance. It can be provided with some slight effect on availability ranging from somewhat enhanced to somewhat reduced, depending on the particular equipment that is used. Several techniques have been developed for monitoring the magnitude of the contained charge, and several algorithms have been used to control mill feed rate and mill speed. The various benefits and the means by which they can be realized are examined and compared. Reasons for Variable SpeedProcess RequirementsThe recovery of minerals from ore is dependent on particle size and residence time in process. Separation in a given plant is most efficient at a particular rate and a particular size (e.g., 80% minus 200 mesh). If the particle size increases, less mineral will be liberated. If the particle size is significantly reduced, the process of choice may not be able to effect separation, and power, media, and maintenance costs would be increased.If a SAG mill-ball mill combination delivers the desired throughput at the correct size for efficient separation when processing ore of the design hardness, some adjustment must be made to maintain this condition when the ore changes. The processing of ore softer than design will result in overgrinding, unless:• the throughput is increased inversely to the change in hardness which lowers recovery by overloading the separation facilities;• or the SAG mill feed rate remains constant, but the speed is reduced to feed coarser material to the ball mill for finish grinding to the desired size.There is also the effect of changing milldiameter to consider. A nominal 36 ft diameter SAG mill will have an effective diameter of 35 ft with new liners and 35 ft 6 in. with worn liners. A mill designed to operate at 0.76 p.u. (per unit) of critical speed with new liners (9.84 rpm) will be changed to 0.765 p.u. with worn liners. If 0.76 p.u. is the desired value, the mill speed should be reduced to 9.77 rpm."

Jan 1, 2003

By Ö. Erdem

The investment decision making process in the insurance and finance industries is affected by new advances such as simulation techniques. These advances have improved the discounted cash flow method (DCF). In DCF, a dynamic and flexible model construction is not possible because it does not consider uncertain conditions. Each project should be evaluated taking into account the related uncertainties because the related uncertainties determine the characterization of the project. Related uncertainties can be processed in dynamic DCF, which is applicable to both financial and non-financial industries with different kind of uncertainties, such as power generation and petroleum projects. The dynamic DCF method can estimate net present value (NPV) while managing related project uncertainties with a simulation method like Monte Carlo Simulation. The simulation method is preferred because its output is unbiased. Therefore, a more realistic financial evaluation of the project can be concluded. In spite of the improvement of dynamic DCF, this project evaluation method is not used frequently in mining industry. However, the mining industry is ideally suited to this concept because it is highly dependent on estimations such as orebody size and ore grade. During the project evaluation stage, these uncertainties can be included with the dynamic DCF method. This study aims to contribute to increasing the usage of this method in mining projects. A copper reserve in Turkey is selected as a case study to apply uncertainty assessment for the evaluation of NPV.

Jan 1, 2012

By Marcia L. Harris

The National Institute for Occupational Safety and Health (NIOSH), as part of its continuing research program for evaluating coal dust explosion hazards, has investigated several areas in which current practices may need to be updated in order to adequately protect mines against coal dust propagated explosions. In the United States, current rock dusting requirements remained largely unchanged since 1969. US Title 30 Code of Federal Regulations Section 75.403 is based on a coal dust particle size survey performed in the 1920s and later was supplemented by full-scale testing of the rock dust ability to inert a coal dust explosion. NIOSH recently conducted a comprehensive survey of US underground coal mines to determine the range of coal particle sizes found in dust samples collected from the mine entries. Due to advancements in technology and modern coal mining techniques, the current coal dust particles in intake airways are significantly finer than those found in the mines in the 1920s. According to past full-scale dust explosion test results, the current rock dusting practices used in today?s mines to inert a coal dust explosion may not be adequate. Other closely related issues such as rock dust testing methods and sampling procedures are discussed.

Jan 1, 2009

By D N. B Skinner, M P. Simpson

At Ohio Creek, 3 km northwest of the Thames bonanza goldfield, porphyry Cu-Au mineralisation is hosted in a dacite porphyry associated with porphyry intrusion breccias and overlying andesites and dacites. The geological setting is a Jurassic greywacke basement overlain by Late Miocene andesite-dacite volcanics which are extensively altered to propylitic and argillic assemblages. Diamond drilling at Ohio Creek in 1978-1981 by Amoco Minerals intersected low grade Cu-Au (0.12-0.20% C~ 0.23-0.4 glt Au) mineralisation An advanced argillic 'alteration cap containing quartz-alunite¦dickite or pyrophyllite-dickite¦diaspore is centred on the adjacent Lookout Rocks and has potential for high sulfidation Au-Cu mineralisation. There is a zonation from potassic K-feldspar-magnetitealteration at depth in the dacite porphyry, through an overlying phyllic quartzsericite- pyrite zone which is overprinted by pyrophyllite in the overlying advanced argillic cap. Early quartz stockwork veinlets associated with the potassic alteration contain fluid inclusions that trapped a highly saline (50-80 wt% NaCI equiv) fluid at high temperatures (450 to >600¦C) indicative of a magmatic fluid. Some chalcopyrite is associated with slightly later quartz-magnetite veinlets, but the bulk of the copper occurs as disseminated chalcopyrite associated with the phyllic alteration. The potassic alteration is surrounded and overprinted by propylitic chlorite¦epidote alteration. Late polymetallic sulfide-quartz-anhydrite veins occur within and around the margins of the porphyry system as in the Kaiser Reef. Fluid inclusions associated with these late veins were formed at temperatures of about 250-320¦C from low salinity (1-3 wfl~ NaCI equiv) fluids. The spatial association between porphyry eu-Au mineralisation, advanced argillic alteration and polymetallic sulfide veins suggests that they are genetically part of the same hydrothennal system. This is consistent with reconnaissanceK-Ar dates of 11.6-10.7 Ma for the intrusive porphyry at Ohio Creek, alunite in the advanced argillic alteration zone at Lookout Rocks and sericite selvedges from the Waiotahi gold-quartz veins at Thames.

Jan 1, 1998

The issue of fine coal and tailings dewatering has become of increasing concern to many coal preparation operators, both in Australia and overseas due to a variety of factors. Increasing mechanisation and mining of thinner seams over the past decades has resulted in an increasing amount of fines generation while increasing international trade in coal and tighter environmental constraints on tailings disposal have resulted in the production of these same fines to be an increasing problem. However, technology to date has not always been able to supply a cost-effective solution to the handling of these fines in an efficient and environmentally benign manner. This paper will review the key issues associated with the dewatering of fine coal and tailings, will describe the major current practices and constraints, and finally will indicate alternative technologies that may have to be considered in the near future. For the purpose of this paper, "fine" coal is described as that material less than 0.5 mm in diameter (as this is the most common cutpoint between various plant circuits in Australian practice), although the technological constraints are very much dependent upon the fraction less than 45 micron. The amount of minus 0.5 mm material fed to plants varies, depending upon the type of coal and mining operation, but in Australia may range from less than ten per cent to greater than 30 per cent of the feed in higher rank coals.

Jan 1, 1991

By Huan-Qiang Zhang, Gang-Hai Huang, Yu-Yong Jiao, Fei Zheng, Zhang. Xiu-Li

An efficient and accurate three-dimensional (3-D) contact detection algorithm is of vital importance in large-scale computing of discontinuous deformation analysis. The contact detection algorithm takes up a large proportion of the whole calculation time because of the increasing calculation number in three-dimensional case. For block systems which consist of convex polyhedrons, the efficiency and accuracy of the contact detection algorithm is a great challenge. The presented contact detection algorithm in discontinuous deformation analysis (DDA) method is carried out in three phases: the global neighbour searching, the local contact type searching and the contact transferring. A contact detection algorithm for 3-D DDA is presented with some improvements on the three phases. A grid-based global neighbour searching algorithm is used to eliminate unnecessary neighbour blocks to the exact number. The local contact type searching includes two steps. In the first step, the common plane method is used to determine the contact type between convex polyhedrons. In the second step, the contact pairs detected by the common plane method are divided into four basic types. In the third phase, the four contact types are transferred into two basic contact types, vertex-to-face contact type and edge-to-edge contact type, which are managed in a uniform procedure. Three verification examples are calculated, the results show that the proposed algorithm based on the three contact detection phases is robust and efficient.

Jan 1, 2015

By M. Kreuh

Crystalline Mg(OH)Cl and amorphous Mg2(OH)3C1 were successfully isolated from a hydrolyzed molten salt electrolyte sample in this work, It was found that the chemical form and crystallinity of the hydroxylchloride were controlled by the cooling rate of the molten sample when it was taken. Crystalline Mg(OH)Cl could only be obtained by cooling the molten electrolyte sample at a rate not faster than 0.6 °C/min, Upon more rapid cooling, the hydroxylchloride species precipitated as Mg2(OH)3Cl, The behavior of these solid hydroxylchlorides when contacted with fresh and non-hydrolyzed molten electrolyte at 550°C was also examined, It was found that the Mg(OH)Cl rapidly dissolved in the hot electrolyte and did not decompose into MgO at that temperature as would be expected from the literature, The dissolution rate of solid Mg2(OH)3Cl was found to be so slow by comparison that it resulted in the complete decomposition into MgO which thereafter was incorporated into the electrolyte as a suspended solid phase rather than dissolution.

Jan 1, 2004

By Richards JR, Herbert HK

A basic question in preparing this review was how to define sulphur mineral occurrences as being associated with the Pacific Rim. This question will be reconsidered later. The isotope composition of sulphur- containing minerals may be considered in terms of two primary sources - 1. deep- seated sulphur, devoid of crustal contam- ination with a 634S value near 00/0o and 2. oceanic sulphate which fluctuated in value between +10 and +300/00 over geological time (Claypool et al., 1980). However, minerals have seldom been directly derived from these primary sources as even evaporites have been dissolved and reprecipitated. The marine source is differentiated biochemically and isotopically in recent sediments where sulphide from bacterial sulphate reduction may be significantly depleted in 31S. The question of chemical interaction of ascend- ing magma with upper crustal rocks has become one of degree rather than whether or not it occurs. Mineral deposition is considered increasingly in terms of mixing of fluids and their chemical reactions with rocks rather than direct precipitation from magmas or hydrothermal fluids derived from them.

Jan 1, 1987

By R. Hogg

The sedimentation and dewatering characteristics of flocculated slurries are determined by the size and density of the flocs. Studies of the formation and growth of flocs reveal that floc size is limited by breakage of the agglomerates due to shear in the suspension. Floc density measurements indicate that there is an inverse relationship between size and density. This relationship appears to be determined primarily by the nature of the solid particles, especially the size distribution, but it appears that agitation of the suspension can lead to some densification of the flocs, in addition to breakage. It follows that both size and density can be controlled to a significant extent by regulating the physical conditions (agitation, method of flocculant addition etc.) during flocculation. The use of physical floc conditioning to control the sedimentation and dewatering (filtration) behavior of flocculated, fine-particle suspensions is evaluated in terms of its effects on floc size end density.

Jan 1, 1986