Search Documents

By Christopher A. Jacobs

Project managers aim to maximise the NPV of their projects, but don't always appreciate the relationship between mine throughput, project value and the discount rate being used to evaluate their projects. Rate of production or throughput is perhaps one of the most crucial decisions a project manager must make, but if this choice is made arbitrarily, much effort may be spent on a feasibility study that does not optimise project value. The timing of the study in relation to the stage of exploration is examined and simple techniques are presented that project engineers and managers can use to home in on a production rate which will give their project the greatest chance of success.

May 1, 2006

By R. A. Ford

The paper outlines: methods used for the determination of wear metals in motor and transmission oils; contaminents in motor, transmission and crusher lubricating oils; and viscosity determinations. Case histories and costs are presented to illustrate the value of an oil analysis program. Introduction NORANDA MINES LIMITED (BELL COPPER DIVISION) is located on the shores of Babine Lake, approximately 450 miles north of Vancouver, British Columbia. Access to the mine is by road from Topley, B.C., about 40 miles away. When a preventive maintenance analysis program was first considered, it was obvious that if samples were to be sent out for analysis, results would not be available for at least a week, due to the distance from any commercial laboratory. The assay laboratory was asked to investigate the possibility of determining wear metals on site. A limited program was started soon after production commenced, and this has now grown to include all large mobile equipment as well as crushers and grinding mills. The laboratory also now determines viscosity, fuel dilution, dirt and abrasives, glycol and water. All these results are ready within two days. This paper will outline the methods used, data interpretation, several case histories and the benefits from such a program.

Jan 1, 1977

By Tim Grain Joseph

This paper considers the duty cycle of an electric cable shovel and correlations with measured passive seismic responses of the underfoot oil sand material in-pit. It has been observed that the cyclic activity during operation of any shovel in the oil sands environment causes the material to deteriorate and provide a less than ideal footing for this large item of equipment, whose dead weight approaches 1500 tons with a footprint of merely 75 square yards. Consequences are manifest in the form of carbody and side frame cracks, and associated downtime, maintenance activity, cost, and subsequent loss of availability. The objective of these considerations, as part of the Oil sands Equipment Interaction Program (OsEIP); currently a joint venture between Syncrude Canada Ltd., JPi Ltd., Caterpillar Inc., P&H MinePro and the University of Alberta; is to identify and provide feedback to the manufacturer and end user adverse shovel - ground conditions. This would enable the manufacturer to incorporate greater knowledge into the design process and the end user to direct operations in an enhanced proactive maintenance stance.

May 1, 2002

By Q. J. Xu

In blasting sensitive areas, the use of traditional blasting for rock fracture is restricted. Soundless cracking technology has been presented to achieve rock fracture instead of blasting. However, when the diameter of a borehole is larger than 50 mm, it is very dangerous that the soundless cracking agent (SCA) will have a tendency to gush from the borehole, which also leads to cracking failure. In this paper, a new large scale borehole soundless cracking technology is presented, using a new enlarged drill bit and mechanical plugging, which could solve the hole gush problem. Experiments were made to measure the expansive pressure of the SCA working in boreholes of F40 mm and F100 mm. The difference between two sizes of cracking phenomenon was compared and analyzed to show that large scale borehole soundless cracking has larger expansion pressure and faster reaction speed than traditional soundless cracking. Based on the experimental data, finite element analysis was utilized to study the stress concentration and stress distribution between two neighboring large boreholes in several media during the cracking process. Using the data from experiments with finite element numerical simulation, the brittle material fracture condition was analyzed to design the parameters of the borehole mesh. With the theoretical analysis, the technological process and reference parameters of large scale borehole soundless cracking were proposed, including the borehole spacing, burden distance, depth of the borehole and so on. Then a single rock was cracked with the new enlarged drill bit and new plugging, and the results proved the feasibility of the new large scale borehole soundless cracking technology, which achieved the expected goal of improving the cracking ability and reducing the cracking time. This paper presents a new efficient rock cracking method for blasting sensitive areas, and which could apply to mining engineering, demolition engineering, excavation engineering and other engineering applications where there is a demand soundless and non-vibration fracturing of rock.

Aug 1, 2013

By J. M. Turnbull

THE primary objective of the young graduate, after the war, will be to obtain a suitable position within the Industry, with adequate pay and opportunity to advance. The positions available to meet this demand will depend on the magnitude and organization of the industry. The size of the mining industry, in particular, will depend on a number of factors, including depletion; new discoveries of mineral deposits; beneficiation of new kinds of mineral deposits, based on research; technical improvements, also based on research, enabling the mining of lower grade deposits; and complex social factors. The organization of the industry will depend on its control and management, which may be greatly affected by social conditions and changes, and may include a wider or a narrower use of technical services. The corresponding training or qualifications of graduates, to meet these conditions, calls for a consideration of educational requirements and facilities in relation to the conditions that are likely to occur. Some forecast of the probable future of the Industry, after the war, based on consideration of. the above factors, is necessary as a basis of discussion, since the graduate must find his place in the industry of that time, and find his work in maintaining and improving it, within the existent social framework. Social factors are pressing and? important at present and their future impact is uncertain. In considering these, a few quotations and extracts may be in order. "A new economic order, based on free access to the sources of raw materials, means free use of the world's wealth by all civilized nations" (The Pope. Also advocated by Churchill and Roosevelt in the Atlantic Charter). "Every citizen should have a voice in the conduct of business or industry which is ?carried on by means of his labour" (Archbishop of Canterbury).

Jan 1, 1943

By John A. Dresser

At a meeting of the Montreal Branch of this Institute in the autumn of 1928, the Honorable J. E. Perrault, Minister of Mines for Quebec, announced his intention to enlarge the Bureau of Mines of Quebec by the addition of a Division of Geology. The announcement further stated that the geological work proposed should be begun in the following field season, and that it should be on a substantial scale of not less than six field parties. The announcement was received with enthusiasm and much encouragement was held out for the success of the effort. It has been thought that the present meeting would be a suitable occasion to present a report of progress of this Division for the three years that have since elapsed. History This, of course, is not the first geological work to be undertaken by the Bureau of Mines. Prior to the establishment of the Division of Geology, the Bureau of Mines had not been unmindful of the need of geological research, but it had always lacked the means necessary to any sustained work. For more than 25 years the late J. Obalski was the Superintendent and the sole occupant of the Bureau. Yet, even then, Obalski, besides routine visits to mining districts, made a few exploratory trips along the north shore of the St. Lawrence river and one to Chibougamau, but without the equipment necessary to effective results.

Jan 1, 1932

By N. Nemeth

A brief summary of available filtration research is given. Its usefulness and shortcomings to practical application are examined and suggestions for new avenues of research outlined.

Jan 1, 1967

By SeyedBijan Mahbaz

Development of Geomechanical Earth Models (GEM) is a prerequisite to reservoir management, involving issues such as stress path analysis, prediction of induced seismicity and sanding initiation, and coupled flow-stress modeling that leads to more realistic predictions of oil rates and rock response. Part of GEM development is the stipulation of the 3-D lithostratigraphic disposition (geometry) which is used to choose the geomechanical units. The digital geological model is then populated with quantitative and semi-quantitative data on rock properties, fluid properties, saturations, initial conditions (p, T, [_]) and other information. Both fluid and solid properties are needed this requires integration of geomechanics skills with geophysical and rock physics skills, and this article deals with a subset of this integration process, with an example from two wells in southwest Iran.Rock physics approaches are used to predict reservoir rock and fluid properties with wellbore and 3-D seismic data, which are also used to interpolate rock mechanics properties to the inter-well regions. The first step in a generic rock physics approach is diagnostic and involves the introduction of a suitable Rock Physics model.Acoustic impedance (AI), shear impedance (SI), and density (_) are the fundamental rock properties usually derived using AVO equations, and these parameters, along with attenuation coefficients, can then be correlated to static rock mechanics properties that define deformability and perhaps even strength. In this study, Poisson Impedance is introduced as a new seismic attribute used for lithology and fluid differentiation in the FahliyanFormation (reservoir rock) in two oil wells in the southwest of Iran. To do this, a novel rock physics model was developed for this naturally fractured carbonate reservoir.Currently, these data are also being used to correlate to a limited rock mechanics data base to develop a more extensive GEM to serve as input to more general geomechanical and reservoir modeling tasks.

Jun 1, 2012

By D. Mu

A method is presented for evaluating the effective gas diffusion coefficient of porous media. A series of random-distributed porous solids with different porosity are generated, a solution of the gas diffusion equations inside the porous media is obtained using the finite element method (FEM), and then the effective gas diffusivities are computed. The results show that there is a percolation threshold sp, and this percolation threshold decreases with an increase in the connectivity of the pore network; the relationship between the effective diffusivity and the porosity is strongly nonlinear when the porosity £ is less than about 0.2; and is quasi linear for higher porosities. The threshold decreases with increasing the connectivity of the pore network. A formula relating the effective diffusion coefficient with porosity is proposed.

Jan 1, 2005

By J. Sugai

Formability of extruded round AZ31 magnesium alloy tubes with different manganese concentrations was evaluated by performing bending tests and measuring strain along the length of the tubes during the bending process. It was found that an increase in the manganese content from 0.3 % to 0.7% did not exert any significant effect on the values of yield stress, elongation, or compression to fracture. However the hardness tended to increase and the UTS decreased. The compressive ductility was significantly lower than tensile ductility for all manganese concentrations. Consequently, the formability of tubes decreased, causing cracks in areas where compression strain occurred during bending. It was also found that a larger strain occurred in the latter half of the region along the length of tube between the clamp-end and the tube-positioning block. Within this region, alloy tubes with higher manganese concentrations, 0.5 and 0.7 %, there was a clear strain peak within the strain profile, while for the 0.3 % Mn alloy, a more uniform strain profile was exhibited, indicating a more uniform deformation. This was confirmed by microstructural analysis of the specimens.

Jan 1, 2006

By S. Vaidya, R. C. McKellar, N. K. Sinha

Nominally [001]-oriented nickel-base single crystal (SX) superalloy CMSX-10 was investigated at 900°C under constant load, equivalent to an initial stress of 700 MPa, for creep strains from 7% to fracture strain (18.2%). The cross-sectional dimensions of initially uniform cylindrical specimens were measured along their entire length after the tests. The cross-section changed from circular to near elliptical shape. The anisotropic deformation, measured in terms of eccentricity, increased with the increasing strain level, but for a given strain level, it remained constant along the entire length of the initially uniform gauge section. The results are discussed in terms of diameter, eccentricity, area, local stress and microstructural observations. The most striking observation was the fact that all the specimens displayed a yoke-like shape, or the reduction of cross sectional area, at two locations within the originally uniform gauge section. Such observations have not been reported in the literature for single crystal superalloys.

Jan 1, 2006

By J. D. Stewart

One of the first important questions that should be settled on the opening of a mine or the development of a new deep is the system of haulage to be used, since the layout of the haulage-ways at the pit bottom, or, in case of a slope mine, the arrangement of the surface works, depends largely upon the type selected. Should it later become desirable to install a system of haulage of a type other than that for which the mine roadways were originally laid out, considerable difficulty would likely be encountered in its installation and with the result that it would in all probability be most unsatisfactory and expensive in its operations. It therefore becomes very necessary that full consideration be given the haulage problem at an early date in order that the type best suited to the mine conditions and the required outputs can be intelligently planned for. It is sometimes found, however, that no matter how well the mining engineer explores the seam to be developed, or how accurately he anticipates its eccentricities, there will still remain some unrevealed or unsuspected conditions, or shall we say obstacles, placed by Nature to prevent the too easy winning of her treasures and incidentally to frustrate or modify the application of the plan so painstakingly laid down on paper, and to adversely affect the cost estimate.

Jan 1, 1928

By H. A. Wentworth

The Central Manitoba mining district, as spoken of in Manitoba, refers to that portion of the country lying between lake Winnipeg on the west and the Ontario boundary on the east, and from a few miles north of the Wanipigow (or Hole) river on the north, to a few miles south of the Bird river. It embraces two known mineralized belts; the gold area in the north, extending from the shores of lake Winnipeg almost to the Ontario boundary (in a slightly southeasterly direction) a zone some eight or ten miles wide and perhaps forty miles long, lying (for the most part) north, and parallel to, the Manigotagan river; and the Bird river copper and coppernickel deposits, an area not yet clearly defined, but in general lying immediately north of, and roughly parallel to, the Bird river. To the south of the Bird river is a somewhat differently mineralized area, numerous pegmatite dykes being found, with minerals typically associated with such rocks. More specifically, the known gold deposits are largely segregated in the above belt; (1) around English brook; (2) along the north shore of Wanipigow lake; the Rice lake area (about midway of the belt); and the Long Lake-Bulldog lake area, at the eastern end of the belt. Not all the known gold occurences are found in these segregations, but the density of claim staking in these areas is perhaps an indication of the greater number of prospects found in them to date.

Jan 1, 1925

By Mostafa Benzaazoua, Bruno Bussière, Jean Lelièvre

De nombreuses opérations mimères exploitent et traitent des minerais sulfurés pour concentrer des métaux precieux (Au, Ag ... ) OU des métaux de base (Cu, Pb, Zn ... ), laissant en fin de parcours des tonnages considérables de résidus plus ou moins générateurs de drainage minier acide (DMA) selon leur contenu en sulfures. De nos jours, Jes restrictions en matière de protection de l'environnement obligent Jes opérateurs miniers a trouver Jes solutions Jes plus efficaces pour préserver Jes sites environnants de la pollution due a l'oxydation des sulfures. Cette oxydation cause une acidification accrue du milieu et une mise en solution des metaux toxiques. L'utilisation des recouvrements multicouches est l'une des solutions Jes plus efficaces pour limiter la pollution liée au DMA mais entraine des coilts de construction qui sont souvent considérés par l'industrie miniere comme prohibitifs. Une façon de rendre cette technologie applicable, d'un point de vue économique, est de désulfurer Jes résidus à l'usine de traitement et d'utiliser la fraction inerte comme composante d'un recouvrernent multicouche. Cette opération de desulfuration peut etre réalisée par flottation non sélective des résidus dans le but d'obtenir d'une part un faible volume de concentré de sulfures qui devra être géré convenablement et d'autre part un rejet non générateur d'acide.

Jan 1, 1998

By J. Ellis Thomson

For many years the value of qualitative microscopic investigation has been recognized in both of the fields of pure and applied science. In particular, its aid has been invoked in the determination of rock specimens in thin section, and some at least of the interrelations of minerals present in any one section have been observed and, to a limited extent, applied for the solution of different problems. During the past decade this form of research has also been diverted to the determination of ore minerals in polished section, with some observation of their structural relations. Microscopic research of a quantitative character, on the other hand, while started nearly one hundred years ago, has found but a limited application in petrography and has scarcely been used at all in the more modern science of mineragraphy. This is very largely due to the methods employed, since most of them consumed too much time and were, in addition, too laborious to encourage many workers in their use. The details of procedure for these earlier methods will be found in another paper by the writer, and will be omitted from this discussion as being of small interest to practical mining men.

Jan 1, 1930

By S. Maleksaeedi

On-site evaluation of strength using hardness is common for different materials. The lack of such relation for aluminum alloys has always been felt. In this work, a finite element analysis of plastic deformation and its distribution in Brinell hardness testing is presented. The analysis has been performed for different strength levels of aluminum alloys. By utilizing the Von Mises equivalent strain in hardness, it is tried to derive a correlation between hardness and strength values for the alloys under consideration. The derived correlation is verified using the experimental values available in literature.

Jan 1, 2004

By Te Gao

It is a general expectancy that in most of the construction and renovation project, the contractor is going to hand over the as-built documents to the owner or the facility management team at the completion of the project. The main challenge for the handover process is to ensure the completeness of the captured building information and the accuracy of it in terms of how well it represents the reality. Building information models (BIMs) can be used as an information repository to store and deliver as-built information. However, due to changes made in the construction and renovation phases and errors made in the design and modeling phases, discrepancies can exist between BIMs created in the design phase (asdesigned BIMs) and actual building conditions. Laser scanning technology is able to efficiently capture accurate geometric information, which provides an opportunity to identify and quantify discrepancies and update as-designed BIMs into as-built BIMs. This paper presents a case study, within which the asdesigned BIM of a newly renovated research lab was updated into an as-built BIM using laser scanned data captured in the renovation phase. This paper introduces the challenges associated with the updating process for the as-designed BIM. In order to address these challenges, this paper introduces a framework that supports the update of an as-designed BIM by incorporating point clouds captured by the progressive laser scans.

Aug 1, 2013

By L. A. Anestiev

A method based on use of calorimetric data for the determination of solidification kinetic parameters is proposed. The method incorporates recent theories of nucleation and growth and allows modeling heat fluxes observed in calorimetric experiment. Statistically optimal estimations of the kinetic parameters, which include the activation's energies of nucleation and growth, are derived from experimental data by means of nonlinear regression analysis. The method is applicable to pure substances and alloys. The evaluation of the kinetic parameters characterizing solidification of pure Al is used for clarifying and exemplifying the method.

Jan 1, 2004

By R. D. Brown

"AbstractOver the past five years, tax rates in the Canadian mining industry have skyrocketed upward across Canada, as both federal and provincial governments have sought to increase their share of mining revenues.However, the past few years have not only brought high tax rates to the industry, but also a number of important new federal and provincial tax incentives.In large part, these incentives ~ special credits or reduction in tax for carrying out specific exploration, processing or other activities - have helped to moderate the adverse effects of the higher tax rates and have provided inducements for exploration and processing activities which might not otherwise have been undertaken.However, the effectiveness of certain of these incentives can be questioned: our over-all tax structure now consists in large part of punitively high marginal rates with some extraordinarily generous but capricious tax reductions for specific activities and may not be in the best long-term interest of either the industry or the nation.A rational tax structure, with moderate and stable tax rates, together with reasonable incentives confined to activities specifically requiring them, could be a more effective spur to investment than the present tax and incentive jungleIntroductionIN THE YEARS since federal tax reform, the mining industry in Canada has faced a continued escalation in its tax burdens as federal and provincial governments have leapfrogged each other in imposing new and higher taxes on the industry. The result has been that marginal tax rates imposed on mining and processing activities throughout Canada have jumped to hitherto unparalleled levels."

Jan 1, 1977

By Aalbert Zwijnenburg

One of problems connected with the use of gold/titania-based catalyst systems is the low yield in propene oxide (up to 2 wt %). It is shown that the low propene oxide yield is due to product inhibition. New options for propene epoxidation with hydrogen and oxygen are discussed. INTRODUCTION The direct gas-phase synthesis of propene oxide (PO), by the use of molecular oxygen, is still aimed for. Agbased catalysis is in principle possible, but selectivity at present is not promising. Highly dispersed gold on titanium containing catalysts show an extraordinary selectivity in the oxidation of propene to the corresponding epoxide (> 99 %), using a combination of H2 and O2 as oxidation mixture [1]. Additional studies of the epoxidation reaction have indicated several drawbacks of the Au/TiO2 catalyst. Firstly, the low conversion (1- 2 %) obtained under typical reaction conditions (atmospheric pressure, 323 - 423 K) cannot be increased by increasing the reaction temperature, because this leads to extensive by-product formation. Secondly, the low efficiency of hydrogen (relatively large amounts of water are formed) is hard to prevent. Finally, significant deactivation of Au/TiO2 catalysts within several hours on stream has been observed. Deactivation can be almost completely prevented by using dispersed TiO2 supports, such as TiO2/SiO2 and Titanium-Silicalite-1 (TS-1) [2]. In recent literature [2,3] a hydroperoxide-like intermediate has been proposed to be responsible for the selective epoxidation. This oxidising species is said to be formed over gold and subsequently used for epoxidation over the Ti-containing support. The support is responsible for the slow desorption of PO. One of the problems for future industrial application might be the low yield in propene oxide. Furthermore, the presence of minor amounts of by-products, not detected on lab-scale catalyst testing, might complicate the separation unit in an industrial process. The reason for the low PO yield over Au/TiO2-based catalysts will be discussed in this paper. Temperature Programmed Desorption (TPD) and micro-flow experiments have been carried out to study PO desorption and catalyst performance, respectively. A catalytic cycle is proposed together with its consequences for the maximum yield in PO. Finally, several process and catalyst options are discussed in view of potential future industrial application.

Oct 1, 2003