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By Z. G. He, S. H. Chen, P. Egger

A new model for hollow rock bolts which comprises rock material, hollow bolt material, bolt/rock interface, is developed on the base of the composite element method (CEM). The main advantage of the new model is that it can be incorporated into the conventional finite element analysis. So the mesh generation of bolted rock structures becomes more convenient and feasible, which is very important in the optimisation of reinforcement design: the mesh can be kept unchanged when the number and orientation of bolts are adjusted. The comparison of the calculation results with a conventional FE approach shows the robustness of the proposed method. Un nouveau modèle numérique de boulons creux comprenant la roche, le matériau du boulon creux et l’interface roche / boulon est développé sur la base de la méthode des éléments composites (CEM). L’avantage principal du nouveau modèle est la possibilité de l’incorporer dans une analyse aux éléments finis conventionnelle. Ainsi la génération du maillage d’une structure rocheuse ancrée devient plus simple ce qui est très important pour une optimisation du projet : en cas d’ajustement du nombre et de l’orientation des boulons, le maillage reste inchangé. La comparaison de résultats de calcul avec ceux obtenus par un code aux éléments finis conventionnel montre la robustesse de la méthode proposée. Auf der Grundlage der Verbund-Element-Methode (CEM) wird ein neues Modell für hohle Reibungsanker entwickelt, das den Fels, das Ankermaterial und die Kontaktfläche Fels / Anker umfasst. Der Hauptvorteil des neuen Modells ist die Möglichkeit, es in eine konventionelle FE-Analyse einzubetten. So wird die Netz-Generierung für verankerte Fels-Bauwerke einfacher, was für die Optimierung des Verankerungs-Projekts von Wichtigkeit ist: wenn Zahl und Orientierung der Anker variiert werden, bleibt das Netz unverändert. Der Vergleich von Rechenergebnissen mit solchen aus einer konventionellen FE-Rechnung zeigen die Robustheit der vorgestellten Methode.

Jan 1, 2003

By J. S. Orphanos

The requirements for controlling air and stream pollution are a most timely subject for concerned people. The coal industry has taken great measures to reduce pollution. With the use of more efficient scrubbing equipment on their thermal dryers, pollution has been considerably reduced. Furthermore, eliminating thermal drying completely by using centrifugal dryers (Bird screen bowls) to dewater fine coal products and meet consumer specification has completely eliminated air pollution. The coal industry is taking steps to eliminate stream pollution and the hazards created by tailings ponds. These plants are closing their water circuit by recovering all solids in solid-bowl centrifugal equipment. In doing this effectively and economically the water discharged into the streams does not contain any refuse solids. This provides a safe economical method.

Jan 1, 1976

By C Kocsis, G Baiden, Y Bissiri

CANMET-MMSL and Penguin Automation Systems Inc have been exploring how process simulation and ventilation modelling software, when combined, can be used to optimise hard-rock/metal mine ventilation systems. In combination, it is anticipated that this methodology will facilitate the exploration of mine design options that affect ventilation requirements and ultimately cost. Such integrated mine design could limit, and possibly reverse, the drivers that under current practices would generally dictate increased ventilation, power consumption, cost and greenhouse gas emissions. It is believed that the mining industry needs such process models to develop better business cases. For example, the implementation of optimised ventilation systems will undoubtedly require significant investment and mines are often reluctant to try such conservational measures unless they can be proven cost-effective. In general, Canadian hard-rock mines know their ventilation systems are providing too much air and consuming power unnecessarily. This is because their systems are designed to provide maximum production flexibility, based upon peak demand, which may be at some future time, and operated continuously at that level regardless of actual need. Simplistic analyses have shown electrical energy savings can range from 30 per cent through to 90 per cent (Hardcastle, Gangal and Leung, 1998). These savings depend upon such factors as the intensity and continuity of the production schedule as opposed to non-productive time. Where these savings occur is also important, if limited to either the primary or auxiliary ventilation systems, they could be negligible in a mineÆs total energy consumption. The problem these mines face is determining what level of ventilation is required in real-time and then the relative benefits. Such parameters as varying electricity costs, heating fuel options, different design criteria and their complex inter-relationship can effect the selection of an optimal system, depending on whether energy, environment or cost is the prime driver. The use of process simulators in underground mining is in its infancy; to date they have been used to show the benefits over the life of a mine under different mining methods, such as a comparison of tele-remote mining from surface against conventional manned operation (Baiden, 2000). This ongoing development advances the use of such simulators into a new and potentially important area, namely modelling the life-cycle ventilation requirements of a mine. This paper shows how such a life-cycle analysis as opposed to peak demand can provide the basis for optimising the design of ventilation systems and their control.

Jan 1, 2005

Meeting of Apr. 23, 1915.-The Iron and Steel Committee was authorized in its discretion to defer the date of acceptance of papers for the Hadfield Research Prize to Nov. 1, 1916. The sum of $250 was appropriated as a guarantee fund to establish a Library Research Bureau in co-operation with the other Founder Societies. The sum of $50 was appropriated to the Puget Sound Section. The sum of $250 was appropriated to the San Francisco Section. The sum of $125 was appropriated to the St. Louis Section. The matter of memorializing the New York State Constitutional Convention was referred to the New York Section of the Institute with authority to act as a Section only. Upon recommendation of the Committee on Membership, 50 Mem¬bers, 1 Associate, and 6 Junior Members were elected.

Jan 6, 1915

By John P. Gooch

The Bureau of Mines wrote a computer program which calculates the saturation curves and condensation characteristics of gaseous mixtures consisting of binary organic vapor and air. The program employs an algorithm which assumes an equilibrium mechanism for condensation, and the degree of fractionation obtained is predicted on the basis of relative volatility. The program incorporates a feature which allows the user to examine the fractionation resulting from condensation as a function of the size of the temperature increments over which condensation is assumed to occur. If a single. temperature interval between the dewpoint of the mixture and the outlet temperature of the condenser is assumed for the calculation, the results obtained will be those resulting from a single equilibrium condensation. If the condensation is assumed to occur over a number of temperature increments, the results obtained will approach those predicted by the Rayleigh equation as the magnitude of the temperature increments approaches zero. The results from calculations performed on vapor mixtures from organic heavy liquid solutions used in beneficiating potash and brucite ores are presented. The liquids are solutions of dibromomethane in trichloroethylene or perchloroethylene. The results show the degree of liquid recovery which is possible by cooling mixtures of organic vapor in air. Compositions of the vapor range from 10 to 95 percent air, and assumed condenser exit temperatures range from 110° to 50° F.

Jan 1, 1971

The importance of the Broken Hill mining field may be gauged from the fact that since the discovery of the ore-body in 1883, till the end of 1931, approximately 43,000,000 tons of ore have been raised.The lode covers a length of 31 miles, and in places is upwards of 300 ft. in width. The ore, as at present mined, consists of an intimately blended mixture of lead and zinc sulphides with silver and gangue minerals.Structurally the lode conveys the impression of a huge longitudinal arch (when viewed from the east or west), having its apex or crown near the centre of the field, in the leases of the Broken, Hill Proprietary Co. Ltd., where the lode outcropped at the surface.The minimum depth of the lode in the Proprietary mine was some 500 ft. from the surface, but huge undulations, having an average pitch of 45°, carry the extensions of the arch gradually deeper, to those places where active stoping operations are now in progress in the workings of the North mine at one extremity, and the South and Zinc Corporation mines at the other. The depth of the lode from the surface, as exposed at present, is approximately 1700 ft. at these extremities.The structure and physical character of the ore-body, and its containing walls, are so complex and varied that almost every type of mining problem is met with.

Jan 1, 1932

By T. Gong

Often plans to increase plant throughput provide an opportunity for optimising plant equipment and operating methods. This was the case in 2005 at TISCO Jianshan Iron Mine, when an increase in production was planned. The thickening circuit had presented a limitation to the plant throughput and operation with poor overflow clarity and underflow density. Following a course of test work by Outotec, a 53m diameter Supaflo® High Rate Thickener (HRT) was selected for the duty. From early stages of operation of the new thickener, the benefits have been dramatic, including: ? Improved tailings underflow density by 9% ? Improved Overflow clarity to less than 150ppm ? Considerably decreased the water and energy consumption as well as operation cost ? Stable and reliable operation This paper looks at this installation as a case study and compares the previous thickener installa-tion performance with the performance of the single 53m HRT.

Jan 1, 2014

By Thomas O. Glover

The mining industry of Cameroon continued to be dominated by crude petroleum. Crude petroleum production has become the most important facet of Cameroon's economic development. Oil production was estimated to be 6.3 million tons in 1983 compared with 5.2 million tons in 1982 and 4.3 million tons in 1981. Over two-thirds of its export income was attributed to crude oil. The country's only refinery, dedicated in 1981, has a production capacity of 2 million tons. Cameroon has become self- sufficient in petroleum products since commissioning the refinery. The oil sector contributed approximately 13.5% to Cameroon's gross domestic product in 1982-83. Oil production was expected to rise from 125,000 barrels per day in 1983 to 156,000 barrels per day in 1985 when output peaks. Cameroon's ultimate recoverable reserves have been calculated at 100 million tons, or 750 million barrels of oil.

Jan 1, 1985

By John J. Baz-Dresch, Kenneth L. Bickel, Winthrop F. Watts

Catalyzed diesel particulate filters (CDPF's) reduce the concentration of diesel particulate matter (DPM) and may reduce the emissions of carbon monoxide (CO) and hydrocarbons (HC) in diesel exhaust. Asamera Minerals' Cannon Mine first installed CDPF's in 1987, and currently has 12 diesel- powered vehicles equipped with CDPF's. The Cannon Mine and the U.S. Bureau of Mines collaborated to evaluate the durability and performance of a CDPF. One of the CDPF's used at the mine was periodically evaluated in the USBM's diesel emissions laboratory after 839, 1,584, and 2,881 h of in-mine service. The objectives of this report are to present results from the USBM's evaluation of this CDPF, to describe the Cannon Mine's experience and cost analysis of using CDPF's, and to make recommendations for the future use of CDPF's. CDPF's improve air quality at the Cannon Mine, but they frequently become plugged and are subject to excessive mechanical shocks and stress, shortening their useful life. Mine records indicate that CDPF's account for 0.8 to 4.9 pct of the vehicles' operating cost at the mine. CDPF life to date has ranged from 1,671 h to more than 5,992 h. Laboratory tests of the CDPF determined that DPM removal efficiency decreased and regeneration temperature increased over time.

Jan 1, 1994

By Jürgen F. Brune, Alex C. Smith, William D. Monaghan

One of the predominant causes of fires in underground coal mines is flame cutting and welding. These fires can lead to major events such as the explosion that occurred on January 22, 2003 in an airshaft being constructed at the McElroy mine. Six contractors were inside the shaft at the time of the explosion and the explosion fatally injured three and seriously injured three [MSHA 2003]. Understanding the root causes of these fires and explosions will help prevent these types of events from occurring in the future. Fires and explosions require fuel, oxygen and an ignition source (heat). These three items are referred to as a fire triangle. The control of these three items in flame cutting and welding operations is required to prevent fires and or explosions. United States Department of Labor, Mine Safety and Health Administration (MSHA) Reports of Investigation (ROI), MSHA Mine Accident, Injury, and Illness Reports, and the MSHA Mining Industry Accident, Injuries Employment, and Production Data Base were analyzed and interviews and observations with mine workers and welders were conducted to determine the root causes of coal mine fires and explosions caused by flame cutting and welding operations. This paper will discuss the root causes and potential means to reduce the number of fires and resulting fatalities and injuries caused by or due to flame cutting and welding.

By D James

Fletcher Challenge Limited through its subsidiary Grampian Mining Co Limited has carried out an ore evaluation of one of New Zealand's largest known deposits of ilmenite located at Barrytown on the West Coast of the South Island, New Zealand. The ilmenite is located in a beach sand environment which has previously been mined for gold. Two analytical techniques were developed to quantify the resource. Considerable difficulty was experienced in this phase of the evaluation due to the presence of major inclusions within the ilmenite grains. Wet and dry concentration circuits, utilising spiral, wet magnet, high tension and plate electrostatic separators have been designed to produce ilmenite from the ore. Studies to utilise the titanium content of the Barrytown ilmenite have been made. Recent work has been directed towards a titanium dioxide pigment process.

Jan 1, 1986

Cretaceous to Cenozoic sedimentary basins in Western Southland include a wide range of non-marine and marine sediments, in a structurally complex setting dominated by major fault systems. A reassessment of their mineral potential confirms large quantities of nonmetallic minerals (limestone, aggregate, marl), and smaller reserves of bituminous coal, lignite, clays, and oil shale. Hydrocarbon potential is largely untested. Metallic minerals are present in trace amounts, apart from platinum group minerals and some detrital gold. In the offshore area, seismic data suggest the hydrocarbon potential is significant. The Orepuki area has the most interest onshore.

Jan 1, 1992

By Beth Robinson

This first of two articles on the Second Mexican Mining Rail Excursion describes some of the more casual experiences participants enjoyed on last fall’s rail tour of major Mexican mining operations. In this article, Beth Robinson, a graduate student at Colorado School of Mines, describes trip organizers, participants, and some of the unique events occurring during the two-week excursion. Next month, part two of the series will highlight various Mexican mines and plants.

Jan 1, 1982

Rotor speed is one of the key hydrodynamic parameters in froth-flotation and it plays an important role in bubble-particle attachment. Laboratory scale studies for optimizing the rotor speed to achieve maximum flotation rate constant (K) of quartz, ground by ball mill, are. Purity of quartz was 99.4 percent and d80 of ball mill product was 230 µm. Each size fraction was separately subjected to flotation at three different rotor speeds, namely, 1200, 1000 and 800 rpm, and the flotation rate constant was calculated. The results showed that the flotation rate constant was high at the rotor speed of 1200 rpm. The flotation rate constants achieved at 1200 rpm were 8.676, 8.232, 7.818, 7.248, 7.068 and 6.984 min-1forthesize fractions of +300, -300+250, -250+212, -180+150, -150+125 and -125+106 µm, respectively. Keywords: froth flotation, rotor speed, flotation rate constant, ball mill, quartz

Sep 1, 2012

By Kenneth C. Ko

An engineering investigation was carried out on the technical and economic feasibility of implementing flexible liner/backpacking support systems In an advancing tailgate longwall mine. The system for a model mine consists of a circular tube constructed of liner plates and flyash backpacking. Flyash is pneumatically stowed into the tailgate. Small amounts of cement may be mixed to improve the support capability of the fill In difficult local ground conditions. Water is added inside the nozzle immediately prior to spraying. Results of theoretical analyses and a field test show that the designed system is technically feasible, can be cost-competitive, provides more stable ground conditions, and can Increase productivity and coal recovery, when compared with existing retreat longwall systems. In certain mine layouts, the new system can reduce the direct mining costs by a significant amount. The system would be particularly applicable to deeper coal beds with bad ground conditions.

Jan 1, 1980

By S. C. Chelgani

The Thor lake deposit is a world class resource of rare earth (REE) metals and minerals in Canada. Development work to optimize a REE mineral recovery process flow sheet is underway, however, given the ore mineralogy; the developed reagent scheme is relatively complex. As part of a research project, micro flotation tests were conducted on a feed sample in order to examine factors affecting stream partitioning. SEM-EDX was performed to evaluate variability in grain composition between streams (concentrate and tails) and TOF-SIMS surface analysis was used to determine statistically significant differences in surface species particularly related to potential activation (or depression) of the examined mineral phases. SEM-EDX analysis reveal that the concentrate has a significantly higher proportion of REE bearing grains (carbonates and phosphates) relative to the tail (almost none were identified). Spectral fingerprinting by TOF-SIMS has allowed for the identification of all reagent species investigated. Reagent signal intensity discrimination on test stream mineral surfaces was observed by the TOF-SIMS analysis using reagents at plant concentration levels. TOF-SIMS analysis confirmed that REE bearing grains reporting to the concentrate are doing so in response to collector attachment whereas grains reporting to the tail are doing so in response to a lack of collector and/or in combination with the presence of the depressant. The surface analysis of gangue phases reveal a similar reagent discrimination; the signal intensity of collector species was significantly higher on the concentrate samples relative to the tails while depressant species were significantly enriched on the surface of the gangue phases in the tail samples. A detailed evaluation of the surface species representing the various reagents used in flotation scheme revealed a distinct competitive relationship between two of the reagents. The surface analysis identified that when used in concurrently, there appears to be a negative feedback resulting in a significant reduction in loading for several of the collectors on grains reporting to the concentrate. An evaluation of the effect of reagents on REE mineral in pilot plant is currently under way. Key words: Rare earth minerals, Flotation, Surface chemistry, TOF-SIMS, SEM-EDX

Feb 27, 2013

By C. J. H. Brest van Kempen

The objective of this contract was to provide thrust and torque control and visual output torque readout systems to an existing mine roof bolting machine and to test the consistency of torques obtained under actual field conditions. A Lee Norse TD1 roof bolter was modified by adding a simple torque sensing device to the drill rotation mechanism and a pneumatic logic control circuit that measures torque and controls the hydraulic circuit to the rotation motor. The modification controls and indicates the final installation torque of mine roof bolts. A total of over 5,000 mechanical roof bolts were installed in an operating coal mine. The installed torque of these bolts were within an error band (standard deviation) of 8%.

Jan 1, 1978

ROBERT M. KEENEY,* Portsmouth, Ohio (written discussion?).- Mr. Coffin has written a most interesting paper that covers most of the uses to which water-cooled devices are subjected; but to meet with the operating department's approval, these devices must effect a saving in cost per ton of ingots produced in the furnace. The making of steel in the open-hearth furnace is dependent entirely on the personal element. It is not possible to charge the furnace with so much raw material, turn on a valve for heat, and by use of recording thermometers, clocks, etc. empty the furnace when a steel is made. Competent men trained to the work must be in charge all the time, and the quality and quantity of steel produced is quite as dependent on the care and working qualities of the furnaces as on the raw material and working of the charge itself. Steel making is hot, hard work and the inducement offered to technical men to take up this work is not sufficient to induce many to enter the field. The result is that most of the workmen in an open-hearth plant, the men who actually operate the furnace and make the steel, are not technical men and do not understand the "whys" and "wherefores " and care less. All this means that a furnace must be built as nearly fool-proof as possible. By this I mean that it is necessary to protect those parts of a furnace most subject to abuse by water-cooled devices whenever possible, and these water-cooled appliances must he as nearly fool-proof as they can be made. The control of the gas entering a furnace is of the utmost importance. This means a properly designed port must have the same design throughout the whole run of the furnace. This is not possible with the ordinary

Jan 6, 1919

By M. Z. A. Bakar

To investigate the differences in the radial drag pick cutting performance in dry and saturated sandstone, a suite of linear rock cutting test was performed using linear rock cutting machine (LRCM). Experimental results of 50 data passes, incorporating 350 data cuts were used to compute cutting, normal and side forces required for determination of other performance related parameters. Although the forces required to cut the dry and saturated rock were in congruence for most of the spacing and depths of cut combinations; but the overall averaged cutting and normal forces for saturated rock cutting were found to be 9.9% and 9.4% respectively higher than the dry rock cutting. The increase in the overall averaged forces was attributed to strength variability of one of the saturated block affecting the overall forces. The side forces experienced a negligible drop in saturated rock cutting. An increase of 28% and 9% in the actual and nominal specific energy values respectively was also recorded when cutting saturated rock as compared to the dry rock cutting. The increase in saturated rock specific energy is attributed to production of large amount of fines and few large sized chips directly contributing towards increase in specific energy. The optimum s/d ratio for dry rock tests was found to lie between 6 and 8 whereas for saturated rock cuts this value lied between 5 and 9.

Jan 1, 2012

By G R. Howard, G Back

Management of information systems for data collection is essential to maintain data integrity and continuity, and manage loss control on a large world-class mine such as Telfer Gold Mine. This paper aims to describe the individual systems and protocols of geological data capture at Telfer, then focus on Quality Assurance Quality Control data as an example of loss control in practice. Loss control systems are required to provide capacity, flexibility, structure and management tools to enhance data interrogation. The data that have been collected can then provide geological, financial, environmental, and contractual information to optimise management of business best practice. Telfer Gold Mine is a wholly owned and operated subsidiary of Newcrest Mining Limited. The mine is located in a remote area of NW Western Australia, and has been operating for 20 years. Geological data have been collected at Telfer since 1973. The data include drilling, assay, geological, survey, structural and geophysical data. Data management has evolved through many systems with data stored on many different hardware and software platforms. Commencing in 1995, collation, standardisation and validation of the historic data was completed. This has resulted in the first Access based drill hole database incorporating all available drilling data. This drill hole database, now hosted in SQL Server, is the hub for all geology related data management systems. The Telfer Gold Mine Geology Department has developed a series of inter-related database systems in order to manage the core geology business issues. Databases relating to drill hole planning, drill contract management, geological logging, accounting (standard costing, forecasting, invoice reconciliation), quality control (QAQC), and environment rehabilitation have all been developed to manage loss control. Management effort to provide adequate data systems and protocols has driven the system from concept to utilisation. The improved productivity, data integrity and data analysis capabilities provided by the new database systems at Telfer have allowed for greater confidence in decision making. Systems such as the drill hole and QAQC databases, when utilised in the proper manner provide up-to-date data analysis for resource audits and contract negotiations. The loss control systems are essential to maintain confidence in data integrity and hence directly effect the future of mining at Telfer.

Jan 1, 2000