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By J. Lebl, S. Bharti, D. J. Cornett

"This paper presents the design and application of blasthole mining to an area at Strathcona Mine previously employing post pillar cut-and-fill. Extensive mining in the area had led to gradually deteriorating ground conditions and post pillar stoping was no longer considered acceptable. Alternative methods had to be investigated.Conventional methods for mining in poor ground were rejected because of the high cost. Blasthole mining was selected because iI offered good productivity and safety with acceptable costs. The design of this approach involved field investigations and the use of numerical modelling to simulate the different blasthole options and their impact on ground stability. The blasthole design incorporated reinforcement with cablebolts, use of a radio-controlled remote LHD unit, large-diameter holes, blast design and wall control. Potentially unstable areas were outlined during mining with ground monitoring instruments and the results used to modify mining plans during the production phase.IntroductionIn underground metal mines there is a need to improve safety and productivity and lower mining costs in order to maintain reasonable rates of return on investment. This requires the application of good engineering design to both mine planning and ground control in order to optimize production and costs and to forecast potential problems during mining. The task becomes more important when extensive mining leads to gradually deteriorating ground conditions, making existing mining methods and techniques no longer acceptable from a safety point of view. Alternative mining methods must, however, be sufficiently productive to ensure profitability. This paper presents an example of the engineering design and operating approach used by Falconbridge in dealing with such a situation at Strathcona Mine."

Jan 1, 1983

By Kosta Fytas, Nour-Eddine Chaouai

"Selection of the appropriate kriging plan during indicator kriging estimations is of a paramount importance to the precision of ore reserve estimation. However, very little is known on the sensitivy of indicator kriging results when changing the kriging plan parameters (mainly search distance and number of samples). This paper evaluates the effect of the search distance and number of samples on indicator kriging results using a gold deposit as a case study.IntroductionBlock estimation using kriging is based on the autocorrelation function (variogram) on one hand and on the kriging plan on the other. As far as the variogram is concerned it is more or less subjectively adjusted and this is reflected on its parameters (range, sill, nugget effect and anisotropy). The effect of a poor estimation of these parameters on the kriging variance of ordinary kriging has been proven very important (Brooker, 1986). Choosing a kriging plan is generally a difficult matter depending on the estimation type (global or local). Generally there is not a unique kriging plan be cause there is not a unique structural analysis (variogram). There are no rules or dogmas in choosing a kriging plan but it is rather a function of the sampling pattern (David, 1982).Structural analysis requires the hypothesis of quasistationarity but very often either the data available within the zone of quasi-stationarity are too many so that the search distance is reduced during kriging or the data are too few to satisfy a stationary kriging system (Journel and Huijbregts 1978). As a rule, the larger the neighbourhood, the more precise the estimates should be , but for large neighbourhoods the hypothesis of stationarity does not always hold (Rivoirard 1987; Armstrong and Champigny 1989)."

Jan 1, 1991

By L. Dekker

"In 1979 Chevron Standard Limited and Irving Oil Limited intersected a thick, high-grade sylvinite zone in the Windsor Group in the Chevron Irving Malagawatch No. I well in central Cape Breton. This well was the third and final hole of a program designed to evaluate a non-commercial oil discovery made by Chevron Standard's Mineral Staff in 1978 while carrying out base metal exploration. Nine holes were subsequently drilled to evaluate the significance of the potash discovery. The delineation drilling proved the Malagawatch structure to be complex with the potash zone showing erratic grade and thickness distribution. Based on the drill information the potash accumulation at Malagawatch is uneconomic, however, other salt ""structures"" in the Bras d'Or Basin may in time prove to have better potential.History of DiscoveryIn 1972 Cuvier Mines discovered the Gays River lead-zinc deposit (MacEachern and Hannon, 1974) which prompted Chevron Standard's Minerals Staff to carry out a study of the Windsor basins in Nova Scotia (Figs. I and 2). As a result of this program several carbonate-hosted lead-zinc prospects were identified in the basal Windsor carbonate; one of these was at Malagawatch on Cape Breton Island . In 1978, after preliminary exploration surveys, a diamond drill program commenced consisting of 5 BQ holes (Fig. 3), three of which tested the basal carbonate. Instead of the reefoid bank facies of the Gays River Formation (Giles et al., 1979), the favoured host for economic base metal mineralization, this carbonate was developed as a laminated, pelletoidal, lime packstone more characteristic of the facies equivalent Macumber Formation (Schenk, 1967). While drilling one of these holes, No. 3-78, oil scum was intermittently detected on the drilling mud. The hole was abandoned at 191 m in anhydrite, without having reached the basal limestone."

Jan 1, 1985

By R. C. Lo, M. D. Scott

"This paper reviews tailings management at Highland Valley Copper, and outlines main features of its tailings storage facility enclosed between the H-H and L-L dams. Key management focusses are: energy efficiency, cost effectiveness, safety and integrity of the tailings impoundment, environmental protection, and reclamation after decommissioning. Main features of the tailings facility include: high international standards for seismic and flood design criteria, water management and water quality monitoring, operations and construction optimization, reclamation and decommissioning plan, and geotechnical challenges associated with the complex geology of the L-L tailings dam foundation.IntroductionHighland Valley Copper stores its tailings mainly in the Highland Valley tailings facility (ultimate capacity: 1.8 billion tonnes). Smaller tailings storage facilities were operated by predecessor companies: the Number One Pond, the Trojan Pond at Bethlehem and the Highmont Pond at the Highmont operation as well as backfilling the Heustis and Jersey lona Pits at Bethlehem. These areas are currently not in use, and are in the reclamation phase prior to decommissioning. This paper focusses on tailings management in the main facility. As indicated in Figure I, the facility includes three tailings dams: these are, going from east to west, the H-H, J-J and L-L Dam, named after the alignment alternatives in the initial feasibility studies. From 1970 to 1977 Canadian Bechtel Ltd. advised Highland Valley Copper's predecessor company Lornex, on tailings storage at the H-H and J-J Dams and on the L-L Dam. Since the completion of the L-L Starter Dam in 1977, Klohn Leonoff Ltd. has provided ongoing consultation and construction monitoring of the raising of the L-L and the H-H Dams. The J-J Dams is currently buried by deposited tailings. This paper reviews key tailings management focusses and main features of the tailings facility."

Jan 1, 1992

By D. Mraz

"Under high pressure in a deep potash mine, the salt rock behaves in accordance with the concept of a generalized, perfectly plastic substance. The paper presents the evidence of this behaviour and engineering concepts f or room-and-pillar design. IntroductionThe mining and refining facilities at International Minerals &. Chemical Corporation (Canada) Limited are located near Esterhaz y at the southeastern edge of the Saskatchewan evaporites. Ore extraction began in 1962 and at the present time the annual mining capacity is in excess of eleven million tons of potash ore.A generalized geological section is shown in Figure I. The mining horizon is overlay in by 100 feet of rock salt followed by a thin bed of competent dry shale. The strata in the next 1,500 feet are generally competent and locally water bearing. The Blairmore formation contains strata of water-bearing unconsolidated sand. Below the mining horizon, rock salt is interbedded with anhydrite bands.The 8-foot mining bed is distinguished mainly by grade and clay content, as there is no definite bed boundary. The chief mineral s are halite, sylvite and, in some cases, carnallite, with up to 2 per cent disseminated clay. The ore is coarse grained, with crystals averaging one-half to three-quarters inch across.The major mining problem is related to the fact that the Dawson Bay formation, overlying the evaporites, contains areas and channels that are highly porous and permeable and are filled with unsaturated brine under high pressure. Consequently, all mining areas, with no exception, must be so designed that the overburden salt stratum remain s competently supported for the duration of the mine .This paper outlines a successful engineering method of determining the stability of the pillar s and designing a stable room -and-pillar mining system."

Jan 1, 1980

By V. C. Pandolfelli, P. Bonadia, F. A. O. Valenzuela, L. R. Bittencourt

Refractories for aluminum cells, if not properly selected, can lead to increased energy consumption and even shorten the pot life. Based on recent advances in understanding the deterioration mechanism of cathode materials, several commercial bricks in the SiO2-Al2O3 system were compared to the one used by an Alcoa smelter. Both physical and chemical properties were considered in the selection of the refractories. A more reliable method of permeability measurement, which takes into account inertial and viscous effects during the fluid flow, was applied. Additionally, the traditional cup test and other characterization techniques, such as thermal conductivity, X-ray diffraction, and mercury porosimetry, indicated that a brick with a relatively low alumina/silica ratio, presenting low open porosity and low permeability, far exceeded the performance of the brick currently in use.

Jan 1, 2004

By Simon D. Handelsman, Malcolm Scoble, Marcello Veiga

"Abstract - In many mining areas, potentially profitable mineral projects can be at risk because local people do not trust their governments and mining companies on many issues, including human rights. Projects will continue to be vulnerable to potential failure, delays, and higher costs. This paper suggests that geoscientists need to be aware of the global challenges they face from issues of corporate social responsibility, sustainable development, and human rights. These are not areas in which geoscience education has traditionally focused.This paper examines the types of conflict concerning human rights that are encountered by geoscientists involved in mineral exploration and development. It provides a background to human rights issues and presents a classification of the types of issue encountered. It reports on a survey of case studies that provide examples of the breadth, complexities, and consequences of such issues. The paper then concludes by outlining the development of codes and standards to improve performance, and suggests approaches for positive, practical engagement."

Jan 1, 2003

By J. Beddoes

The various microstructural factors that influence the creep resistance of y-titanium aluminides are presented and discussed. Titanium aluminides have potential for a variety of intermediate temperature applications in both gas turbine and reciprocating engines. While it is well established that the 'fully lamellar' titanium aluminide microstructure offers superior creep properties, the particular influence of lamellar morphology, third phase precipitation, and grain boundary structure in controlling both the primary and tertiary creep behaviour is presented. The results are primarily based on tensile creep experiments undertaken using several titanium aluminide intermetallic compositions processed via powder metallurgical techniques, investment casting and Bridgman directional solidification. The results indicate that lamellar structure and precipitate formation have a major impact on primary creep, while microstructural degradation through both lamellar and precipitate coarsening influence on the onset of tertiary creep leading to fracture. The results are used to design a creep resistant microstructure produced by directional solidification and the effectiveness of this designed microstructure is demonstrated through 10,000 hour creep tests.

Jan 1, 2004

By R. D. MacEchern, M. C. Rockwell

"This paper describes the research and tests carried out to recover the readily available barite from the tailings produced by the Nystone Chemical Ltd. operation at Debert, N.S. The tailings comprised 70-80% of the original feed and contained about 20-25% Baso4 .The objective of the research, undertaken during 1982, was to produce a barite concentrate which would meet the American Petroleum Institute (API) barite requirements for use in drilling mud. Samples from the tailings pond were examined and analysed to determine the tailings characteristics.Preliminary test work was performed on the tailings samples using a Haultain Superpanner, Wilfley tables and Humphrey's spirals. The grade of the barite concentrate retrieved did not satisfy the API barite requirements.The fineness of the tailings and the fact that approximately 80% of the barite was contained in the -200 mesh (0.074 mm) size fractions, indicated that flotation of barite from the tailings might be successful."

Jan 1, 1984

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By D. Milne

Laser profilometers exist for obtaining very accurate two and three dimensional profiles of joint surfaces. The application of this technology is not commonly applied to the collection of field data on discontinuity surface roughness. Rugged and portable field devices are not commonly used and the value of the possible field data that can be collected has not been well recognised. This paper reviews commonly used field techniques for assessing discontinuity roughness, discusses the value of this data and presents a new laser profilometer design for field application.

May 1, 2009

By Tony B. Szwilski

"The efficiency of operation and life of an advancing longwall coalface depends, to a great extent. on the face-end roof strata conditions and the stability of the gateroads. The factors that influence the rate of closure of gateroads are examined, in particular the gateside pack and the coal rib (crush) pillars. The performance of mechanized packing systems is briefly discussed. Gateroad deformation surveys were carried out at two coal mines to determine the influence of the rib pillar width on gateroad stability; also, the influence of the gateside pack on the immediate roof and floor strata is analyzed based on strata bed displacement measurements from instruments installed in the gateroad and pack-hole of a longwall advancing face operating in a thick seam (7.55 m). Concluding, an evaluation of the fac e-end systems examined is given and recommendations made f or the most suitable rib pillar width. face-end geometry and roof strata reinforcement.IntroductionKevword s: Coal mining, Pillars, Rib pillars, Ground control, Longwall mining, Gateroads , Packing systems, Roof control. The face-end region of a longwall advancing face is the center of mining activity, being the turn-around point for the coal cutting machine. and the place of gateroad formation and movement of special face-end supports. The design of face-end layouts can be aided by knowledge of strata control parameters, such as the effective loading of the immediate roof strata , convergence of the roof and floor, magnitude and distribution of fractures in the roof strata around the face-end , optimum placement of supports, coal seam thickness and strength characteristics, geometry of layout and interaction from neighbouring workings. Generally, the gateroad is formed by one of three face-end methods: (a) advanced headings, (b) in-line system (gateroad formed at the face) or (c) conventional ripping with or without stable elimination (also halfheading). The quality of gateroad is influenced principally by the face-end system employed, standard of gateside pack and width of pillar. A good standard of gateroad is generally achieved by employing the half-heading face-end system, the gateside pack and coal rib pillar having comparative support/ yield (stiffness factor) characteristics. However, the halfheading is often not favoured due to face operation restrictions."

Jan 1, 1981

By F. Mallozzi

"With the requirements of air pollution codes becoming more and more critical, the role of the ventilation engineer in industry has become an extremely important one. The ventilation engineer must provide the expertise for the selection of equipment and the design of systems which will reduce pollution to an acceptable level. Because pollution control systems involve considerable capital and operating expense, he must have the ability to select, from a wide range of products, the collector which will provide the required performance with a minimum of down time for maintenance. This paper discusses the principles of wet collection and the forces used to separate particulate matter from a gas stream. Important factors in the selection of equipment, such as collection efficiency, horsepower requirements and water consumption for the various types of collectors, are discussed in detail, as well as the construction features normally incorporated to circumvent potential problems."

Jan 1, 1971

By J. Bhattacharya, S. K. Mukhopadhyay, S. K. Pal

"While time and again many authors have categorically stressed the restoration of the environment, very little effort has been made in the mineral industry to develop the economy of environmental control. There are many abatement procedures that search a maze of variants. Among them pricing environmental damage seems to be more logical and easily implementable.IntroductionMining as an operation has a severe impact on the Earth's natural resources. While economical environment control is much sought after, solutions are often varied and complex, and can differ in the problems of single or multiple mine sites.Determination of Optimum use LevelsIn “mining environmental control"" it is required to strike a balance to find optimum use levels. The solution is to find where the welfare benefits equal the cost involved to curb the degree of environmental damage (Fig . I) . In the mining industries this can be done by modifying the production/extraction process itself. For most pollutants, the marginal costs of control will exceed the benefits from further reduction of damage long before the zero pollution damage point is reached (Fig. I). From an economic perspective the optimal alteration of environment by mining would occur at z; pollution continues to be caused by ""zy"" control units, but it would be inefficient to pursue the redemption efforts further because the marginal cost involved would exceed marginal welfare benefits."

Jan 1, 1992

By Sheila E. Daniel

"Since 1989, the Mine Environmental Neutral Drainage Program (MEND) has sponsored research into ways of reducing the environmental impact and financial liabilities associated with Acid Mine Drainage from tailings and waste rock. Toward this overall objective, Kilborn was contracted to review the use and applicability of passive treatment systems for acid mine drainage.Experimentation using passive systems to treat acid mine drainage has been ongoing since the early 1980's in North America. Passive treatments are generally considered an attractive alternative to active lime treatment, since they require minimal human involvement, no power, and only seasonal or periodic care and maintenance after establishment. Most attractive is that initial capital cost to implement a passive treatement system is generally low to moderate. Ongoing operating costs are similarly low when compared to active treatment systems.Passive treatment systems currently used, or under investigation to treat acid mine drainage include: anoxic limestone drains, aerobic wetlands, reed bed wetlands, compost wetlands, microbial systems and bioabsorption systems. These wastewater treatment systems utilize the chemical, biological and physical removal processes that occur naturally in the environment to improve wastewater quality, including: oxidation, reduction, coagulation, adsorption, absorption and precipitation; microbial activity; and, gravity aeration and dilution. The rates at which these processes occur determines the loading which can be treated and the effectiveness of the system.The results of our literature review will be summarized, and insight provided into the applicability of passive systems to treat acid mine drainage from Canadian Mines."

Jan 1, 1995

By S. Hon, C. Searcy, R. DasGupta, B. Fleet, A. Davidse, A. Pringle

"The mining industry is facing serious long- and short-term challenges relating to uncertain commodity prices, environmental pressures, and margin compression due to rising energy costs. Energy issues, formerly treated as an operating cost, are changing as executives search for longer term solutions to deal with uncertain fossil fuel prices and greenhouse gas emissions. Consequently, mining executives are increasingly willing to consider introducing a proportion of renewable energy (RE) systems into the mine energy mix. This paper examines how RE can be successfully integrated at mine sites, as well as some of the benefits and barriers to their wider adoption.RÉSUMÉ L’industrie minière fait face à de sérieux défis, à long et à court terme, en raison de l’incertitude des prix des matières premières, des pressions environnementales et des compressions de la marge bénéficiaire dues à la hausse des coûts de l’énergie. Les questions énergétiques, auparavant considérées comme un coût d’exploitation, changent alors que les cadres cherchent des solutions à plus long terme afin de prendre des mesures pour contrer les prix incertains des combustibles fossiles et les émissions des gaz à effet de serre. C’est pourquoi les cadres miniers sont de plus en plus disposés à considérer l’introduction d’une proportion de systèmes d’énergie renouvelable dans l’équation énergétique de la mine. Le présent article traite de la manière dont les énergies renouvelables peuvent être introduites avec succès aux sites miniers ainsi que quelques-uns des avantages et des barrières à leur application à une plus grande échelle."

Jan 1, 2015

By Zia Pirzada

"Time is of the essence" and "Time is money" These are powerful and true statements during a project life cycle and have far-reaching implications on the success and failure of the project Time and progress management is crucial to the project success. Project delays may increase the cost to an unacceptable level and may render the project as economically unfeasible. On the other hand, if the project is completed on time or earlier than as planned, it may generate economic benefits greater than what had been envisioned To take advantage of the financial opportunities and to improve the cash flow as well as Return On Investment (POI), project schedule can be accelerated to complete the project earlier than planned Project schedule acceleration can be achieved by using analytical tools, such as "Schedule Optimization", "Schedule Reduction", "Schedule Compression" or a combination of any of these concepts along with the "Planning for start up". Schedule optimization does not entail any extra cost, however, other acceleration methods, such as Schedule Reduction and Schedule Compression, may require extra expenditures from the owner. Based on the forecasted early start of the revenue stream, the extra expenditure could become a worthwhile venture with a very high rate of return To accelerate the schedule, all aspects of the project should be reviewed with acceleration costs calculated. All risks and opportunities should be evaluated and taken into consideration to determine if the acceleration is feasible and advisable and will provide definite financial advantages Sometimes schedule acceleration may be desired to prevent the company from paying liquidated damages. This is especially true when the project is not expected to complete on the contractual completion date and when the cost of acceleration is less than the liquidated damages that may accrue against the company.

Oct 1, 2010

By J. A. Meech, C. A. Harris

"The application of control theory in mineral processing is more difficult than in other industries because of the complex nature of the unit processes involved and because of problems with accurate on stream measurement of process variables. Conventional control is based on proportional, integral and derivative functions of a continuously measured error term. Computer control can enhance these actions by incorporating logical routines to switch from one relationship to another. The success of this logical approach depends on our understanding of the process dynamics and the stability of the process and model under all conditions. Typically the model does not apply at all times in mineral processing because of frequent and unmeasurable changes in the ore parameters.Recent advances in the theory of fuzzy sets have led to the application of this science to process control. Fuzzy Logic can be used to develop heuristic or rule-of-thumb controllers with the strategy based on the actual operating practice of experienced plant operators. Control action has increased flexibility through the adaptation of human reasoning. Acceptance of the control system by operating personnel is significantly higher because of their participation in its formulation. The requirement of an exact model is not essential.A heuristic controller has been designed and tested with a computer simulation model of a secondary crushing plant. The results of this study are discussed and future applications of this control technique to other mineral processes are suggested. IntroductionThe application of control theory in mineral processing is more difficult than in other industries because of the complex nature of the unit processes involved. Mineral processes typically are characterized by non-linear relationships between input and output variables. Many of these variables cannot be monitored accurately on-stream and so long time lags on the measurement loop are features of the system. The processes, themselves, often have long time-varying responses while the process loads fluctuate significantly on a short-term basis.Attempts to control these processes have led to the formulation of mathematical models to describe each unit activity. Adaptive techniques have also been tried to compensate and account for process changes and vageries. These approaches are mathematically rigorous so that their complexity and precision limit their usefulness when applied to ""vague"" processes."

Jan 1, 1987

By Juan C. Sotomayor Álvarez

The Huantajalla mine is seated on Uchucchacua 's Mixing District that is the fourth producer of Silver in the world. Huantajalla Mine is a new mine that nowadays is being explored and recently it has began to operate. The project for 4-A vein exploitation in Huantajalla Mine using Longhole drillings as a new method of mixing is developed by Planning Department of Uchucchacua Mine in coordination with Geology Department of this mine, started in June 2004. This project is funded by Company of Mines Buenaventura S.A.A In July 2002, Geology Department started the exploration on the area of Huantajalla Mine, discovering the 4-A vein. The reconnaissance and definition of the vein finished June 2003, finding 79,080 Ton of mineral of Silver with a grade of 40.0 Oz Ag/ton and a thickness of 1.85 meters (6 feet ). Using the longhole method on the vein exploitation will replace the cut and fill and shrinkage methods, and it will keep a dilution of 15%.

Oct 1, 2004

By D. Laguitton, D. Cimon

"BILMAT is one of the most powerful algorithms in existence for material balance computation in mineral processing flowsheets. It is based on a hierarchical decomposition coupled with the Lagrange multipliers method widely reported in the literature. Flowrates can be calculated optionally for pulp, solid or water. Assays are adjusted for a variety of subnetworks, such as assays of the solid as well as assays of fractions of the solid called level 4 data (l: pulp, 2:solid and water, 3:assays of solid, 4:assays of classes of solid).BILMAT4 is a new implementation of BIU1AT that operates in a new microcomputer environment and makes the method more accessible than ever. Its main features are a full-screen colour editor allowing graphic flowsheet drawing and data entry with automatic error checking. Mass balance equations are automatically generated by analysis of the graphics and corresponding data, thus relieving users from the error-prone definition of networks. Sensitivity analysis is performed to assess confidence intervals of computed flowrates and adjusted assays.BILMAT4 incorporates an option for gold leaching circuits where the element to be balanced appears in both the solid and liquid phases with negligible effect on the mass flows of solids. Recoveries are computed in all streams. This program is currently released by CANMET as part of the CAMP collection for Computer Aided Mineral Processing. A complete sample run of the program is discussed."

Jan 1, 1989