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By James S. Redpath

"AbstractThis paper is an attempt. to outline the present status of underground mining contracting in Canada, and to present certain facts concerning the writing and administration of underground mining contracts which, hopefully, may be useful to those intending to engage a mining contractor . The paper is based on the author' s experience as a contractor and also as a consulting engineer advising others in the purchase of contractors' services.HistoryIN THE early days of mining contracting in Canada, the contractor was primarily a labour contractor. He was expected to bring a good crew of men that normally followed him, and to perform certain work under his own direct supervision. The owner usually looked after all other details including financing, payrolls, withholding taxes, etc , computing and paying the contractor his profit. In the pre-World-War II years, most work was done on this basis.Over the years, the contractor was called on to supply more in the way of services, and the present-day situation evolved.Labour contracts are still used, but now the contractor is expected to carry out his own administration. Most contracts now call for the supply of special tooling required to do the work. In most cases, some, if not all, supplies are the contractor 's responsibility and , in a growing number of cases, the contractor is responsible for such items as design and surveying. The ultimate in this direction is the execution of projects on a turnkey basis. Under this system , the contractor carries the project to a stage where it is turned over fully operational to the owner."

Jan 1, 1977

By B. W. Raymond, D. W. Zandee

"IntroductionCoal deposits are found in many regions in Canada and vary widely in their age, quality and rank. All classifications of coal except anthracite are found in significant quantities in this country.Deposits in the Maritimes are mainly bituminous; Lignite is found in Saskatchewan and Ontario and sub-bituminous coal in the plains region of Alberta. The Rocky Mountain coalfields of Alberta and British Columbia contain low and high-volatile bituminous coal and, in a few places, semi-anthracite. The British Columbia interior contains deposits of semi-anthracite, bituminous, sub-bituminous coals and lignite. The Yukon and Northwest Territories also contain substantial deposits of bituminous coal and lignite.Currently Nova Scotia produces both thermal and metallurgical coal, Saskatchewan produces lignite and Alberta produces both sub-bituminous and bituminous coal for thermal purposes. Large deposits of metallurgical coal are now being exploited in the Rockies arefl of British Columbia and Alberta by open pit methods. The raw coal is treated in large capacity preparation plants to remove refuse and upgrade the product to a consistent metallurgical quality with respect to ash, moisture, volatile matter and coking properties.The treatment of coal involves crushing, screening and cleaning by dense medium, jigs, water-only cyclones, tables and froth flotation to produce a diverse range of coal products differing in quality and size for various end uses.The chapter on Crushing and Screening Circuits was concerned mainly with crushing of metalliferous ores to produce a concentrate of one or more valuable minerals which normally constitute a small portion of the original mass of the material treated.Coal differs physically from ores in many ways such as lower specific gravity, relatively large volumes but low tonnage of product, and its habit of absorbing moisture requires extensive dewatering processes more complicated than settlement and filtration. Most significant, for this paper at least, is the fact that crushing coal is not as energy intensive and much smaller equipment is applicable.Crushing and screening of ores is intended to reduce the size of all constituents as quickly and efficiently as possible to allow liberation of the mineral particles. The crushing of coal is different in that the coal is not the minor constituent and the production of fines, in the initial stages at least, is highly undesirable. The basic objectives of crushing coal are the reduction of run-of-mine material to sizes suitable for cleaning or further reduction of coal to market sizes."

Jan 1, 1989

By R. T. Jones

"Technical publications in the field of mining and metallurgy have existed for a long time. Recent developments in electronic publishing on websites make it possible to disseminate information more widely and cost effectively than before. Professional societies have an opportunity to serve their members and their industry by publishing high-quality peer-reviewed papers on their websites as well as in printed form. Older publications can be scanned, and optical character recognition can be used to provide searchable text. Various business models exist around this process. This paper outlines the approach used by the Southern African Institute of Mining and Metallurgy (SAIMM) to provide free open access to their journal papers and conference proceedings, as well as the work being done by OneMine.org to collect technical papers from a number of international societies and make them available to subscribers via a large database. An approach is outlined that should be of benefit to authors, readers, and society at large.INTRODUCTIONGeorgius Agricola (1494-1555) was not the first writer on the subjects of mining and metallurgy, but is well known as the author of De Re Metallica (‘of things metallic’ or ‘on the nature of metals’), a book that documents and illustrates the observations he made in the course of his extensive travels in the 1500s. Agricola wrote extensively about mining methods and metallurgical processes that were in place in the Middle Ages. The original Latin version of De Re Metallica was published in 1556, the year after Agricola died. It was translated into English by Herbert Hoover, a mining engineer and later President of the United States, and his wife Lou Henry Hoover, a geologist and classicist. The English version of De Re Metallica was published in 1912."

Jan 1, 2012

By Joseph J. Larry

In hard siliceous sandstone strata overlying coal seams, roof bolting is often the bottleneck in the coal production cycle. In the past, these strata have been drilled by pneumatically operated stopers. Although slow drilling is cumbersome and uncomfortably noisy, the stoper was the most effective drill in these harder strata. However, because of the (U.S.) Coal Mining Safety Act, which limits noise levels for operating drills, FMC Mining Equipment developed the water-through-the-drill-steel method of drilling high-compressive-strength strata. Although water-through-the-drill steel had been developed earlier, the real impact of wet drilling techniques surfaced when the dual-boom roof drilling machines were installed at the Virginia-Pocahontas Division, Keen Mountain, Virginia, in 1974. This paper covers some of the technical details of the water-through- the-drill-steel design and its application.

Jan 1, 1979

By H. R. Stockford

"A pyroxenite-carbonatite complex containing extensive pyrochlore mineralization was discovered during January, 1966, within an exploratory license area held by Consolidated Morrison Explorations Limited. Located 32 miles south of Moosonee, Ontario, the deposit was found under 100 feet of glacial till and Paleozoic sedimentary cover using airborne and ground magnetometer surveys. Exploratory and detailed drilling, totalling 47,625 feet in 85 holes, was completed in outlining the deposit to a maximum depth of 900 feet. Pyrochlore reserves are estimated at 62,000,000 tons averaging 0.52 per cent Cb,05 to a depth of 825 feet. Included in this tonnage is a high-grade section containing 10,000 tons per vertical foot grading 0.82 per cent Cb20 5• The deposit is still open at depth and the intrusive complex has by no means been fully explored.The columbium (niobium) mineralization occurs in a lineated calcite-dolomite host rock which has been intruded along a fault zone within a northeast-trending granulite belt. Potassium-argon dating indicates an age of 1655 million years.Preliminary studies suggest that the complex was intruded in a series of pulses in the form of a partially crystallized mush. The James Bay intrusive is unusual in that it is linear in form and contains only two main rock types - p•yroxenite and carbonatite. Nepheline-bearing syenites and associated rocks are notably absent. Moreover, the pyrochlore is essentially non-radioactive and free from many of the impurities generally associated with other pyrochlores. A test shaft to investigate soil conditions and to provide a 250-ton bulk sample was completed during 1968. Subsequent pilot-plant operations indicate that good quality pyrochlore concelttrates can be produced from this deposit."

Jan 1, 1972

By W. B. Burchall

Introduction In presenting this paper the author wishes to state that the opinions here given represent only his personal views. A general survey of the subject has been attempted, but such deductions as may have been drawn are not necessarily endorsed by the Company with which he is associated. The aeroplane as an instrument of transport is yet a novelty, for it is only twenty-five years since man first flew. This statement, by itself, may be very deceptive, for compared with the steam locomotive or even the auto-mobile, this infant in industry has made some remarkable showings. The 'actual performance' speed-curve of aircraft plotted over a ten-year period is rising faster than the 'expectancy' speed-curve of 1924 indicated, and it should be noted that, today, the possibilities of 600 miles per hour provoke less scepticism than did the prophecies of 400 miles per hour only a decade ago. Commencing with the remarkable achievement of raising one man into the air, aircraft with an all-up weight of 14 tons are now in daily use on the British airways, and recently a non-stop flight of 5,340 miles was accomplished in an aeroplane, without refuelling. More true than ever is the statement that the records of yesterday are commonplace tomorrow, for new ideas are today seized on and exploited to the utmost once the period of scepticism and doubt has been overcome. In fact, so many new ideas have been brought forward, during the past few years, and applied successfully in our economic life, that one may well ask if today we are not a little too impatient, too exacting in demands, forgetting that real worth-while progress -is attained by no short-cuts.

Jan 1, 1933

By Alan E. Gallie

FOR many years the Witwatersrand has been the leading gold mining r camp in the world and, to a Canadian mining student, could not fail to be of overwhelming interest. The vast scale upon which the operations are conducted, the enormous production accomplished, and the perfection of the operative technique, have all so forcibly impressed themselves on his memory that it is difficult to select any one feature as more outstanding than another. For the purposes of this paper, however, the author has selected the very first feature of mine operation with which he came in contact, namely, shaft sinking, as it reflects, quite as well as any other, the spirit of mining in South Africa. Early mining in Johannesburg was by open cuts or trenches, dug along the outcrops of the reefs. The ore was thrown from bench to bench to the surface. As the depth increased, rock was hoisted by bullocks. In 1887, the first shafts were sunk and true underground work began. At the same time, boreholes were put down to test the continuity of the reefs at depth. The first was at the Village Main reef. It cut the South reef at 517 feet and the Main reef leader at 581 feet. The Main reef leader assayed eleven penny-weights. Subsequent boreholes proved the reefs down to thousands of feet. Many companies secured deep-level claims as a direct result of the information obtained from the early holes. These companies then held land on which there was no readily available ore. In order to get to their pay rock, vertical shafts through the upper strata were necessary. Shareholders were impatient, and shafts had to be sunk as speedily as possible. The old methods of shaft sinking were investigated, new methods developed, and soon all records were being broken. In the last thirty-five years, the record has been slowly advanced, and last summer it was again broken to stand at 430 feet in a 31-day month. During the period from 1915 to 1935 inclusive, in the Witwatersrand district, 96 miles of shafts were sunk. Today, with the advance in the price of gold and the increase in the mining area, there are over twenty-five major shaft-sinking operations being carried on.

Jan 1, 1937

By D. G. F. Hedley, F. Grant

"In 1958, the Ontario Department of Mines appointed a committee to study the accident situation and mining methods used in the uranium mines in the E1liot Lake district. This committee reviewed the existing knowledge on mine design, pillar support and roof spans and came to the conclusion that scientific knowledge had not yet reached the stage of producing rational design procedures which would reduce the dependence on trial-and-error methods. Since that time, the Mining Research Centre has made numerous stress measurements in two mines to define the pre-mining and pillar stresses. A comprehensive series of tests has been done in the laboratory to measure the compressive strength of the rock; a geological survey of the region has been made to evaluate tectonic stresses; and a survey was done on mining conditions with regard to stable and unstable pillar configurations. This information has been used to evaluate pillar design as effected by pillar width and height, depth below surface, extraction and pre-mining stress fields. The resultant design of pillar widths and corresponding extraction as the depth increased is in line with past and present experience in these mines. The information available on roof stability is still insufficient to design stable stope spans with the same degree of confidence; experience and trial-and-error methods are still required."

Jan 1, 1972

By K. Johanson, M. Hubert, C. Eckert, D. Ghose

The mining industry routinely processes material with different particle sizes. Coal, nickel ore, copper ore, lignite, shale, and phosphate ore are all examples of materials with wide particle size distributions. It is often assumed that these materials are homogenous and that any particle size distribution has the same chemical activity and composition. It is entirely possible, and quite likely, that chemical composition is a function of particle size distribution. In addition, particle size distributions in ore materials are often responsible for the difference in flow behavior in process equipment. This is evident in coal electrical production facilities. Fine coal may have the same ash content, sulfur content, and BTU value as coarse coal. However, all electrical production facilities know the extreme flow problems that result when attempting to handle wet fine coal. Segregation of these bulk materials is an important issue that must be understood to prevent these cohesive flow problems. Additionally, fertilizers are mixtures of particles with different shape and sizes. These mixtures must remain homogenous to optimize fertilizer performance. Segregation leads to poor product quality. This paper presents a method of measuring the magnitude of sifting segregation occurring in bulk material and the relationship between the strength of the bulk material and the separation tendency. It shows an inverse relationship between the yield strength of the material and the bulk segregation.

Jan 1, 2004

By W. G. Millar

Until a fire occurs, insurance and prevention work are often looked on as unavoidable necessities, but as insurance is back of all business credit, it is essential to know that in case of damage money will be available to cover the loss; while the interruption of production, often caused by a fire, brings home the realization that if prevention work avoids such an interruption, it is well worth while. Fire insurance is a legal contract guaranteeing the payment of large amounts to an owner, but it is possible there is no other important contract that receives so little consideration. Although previously carried on elsewhere, it is only of recent years that insurance engineering has been actively followed up in Canada, with inspections of an owner's property carried out for his benefit. Now inspections of this kind are made, advice on fire prevention and protection work ?is available, reports with recommendations with regard to the above are furnished periodically, and with this method applied the owner receives the broadest possible cover and security at the lowest cost. Rates are set by the underwriters by rating schedules which charge for defects in a building and allow credits for protection and other favourable features . These schedules are based on the past record of loss of mining properties as a class, so that a fire in another mining property indirectly affects you, but the amount paid is reduced in proportion as your property is improved. The writer feels, from personal experience, that there is no industry where fire prevention receives more attention than the mining industry, and it is a pleasure to advise that, due to this co-operation, some reduction in the basis rates for mining risks is now being made by the underwriters.

Jan 1, 1928

By J. F. Davis

Pegmatite dykes containing lithium minerals and beryl occur dose to the borders of intrusive masses of granitic rock in the Winnipeg River area of Manitoba. Both vertical and flat-lying dykes are present. Most of the pegmatites consist of zones, containing characteristic mineral assemblages, arranged more or Jess parallel to the borders of the dykes. Five important lithium minerals are present; each occurs in a separate zone, but all the lithium-bearing zones are situated toward the centres of the pegmatites. Spodumene is the most abundant and widespread of the lithium minerals and occurs as small crystals intimately intergrown with quartz. Beryl is not an important constituent of the lithium pegmatites, but when .present, occurs outside the lithium zones, toward the margins of the -dykes. Beryl is most common in dykes containing few or no lithium minerals. The mineral assemblage in the beryl zone of the lithium dykes is the same as that of the beryl dykes. The attitude and internal structure, particularly zoning, of the pegmatite dykes, and the texture and assemblages of the constituent minerals, have an important bearing on exploration, development, and mining of these pegmatites, and on the extraction of various mineral products from them.

Jan 1, 1958

By W. J. Cherones

This paper describes the history of the development and application of the electric mining shovel in open-pit mining, dea1ing particularly with far-reaching advancements in three primary areas: metallurgy, mechanical design and electrical systems. Hoist drives and crowd drives, including the Magnetorque and Electrotorque systems, and the integral propel drive are given close attention.

Jan 1, 1972

By A. Broussaud

The paper describes the advanced grinding control system implemented at Newmont Ahafo gold mine, Ghana in 2009 and 2010. It shows how the different components of the Advanced Process Control (APC) system cooperate for increasing plant performance. The SABC circuit processes hard rock from different pits mixed with a variable proportion of oxides. The control strategy is designed to address specific disturbances, including start/stops of pebble crushers, unavailability of oxides, changes in rock size distribution resulting from segregation in the stockpile, and changes in ore type and hardness. The system consists of an expert system per se with extensive use of fuzzy logic, supplemented by an online dynamic model of the process used as a soft sensor, a VisioRock? rock size measurement system over SAG mill feed before addition of recycled pebbles, and an AudioMill? system to analyze the SAG mill sound and detect impacts on liners. All these components are embedded in the same OCS© software platform, which, among other benefits, makes it easy to support the entire system remotely. The paper details the physical constraints and the variables that are manipulated. It describes the control strategy and the contribution of each component of the system. It also describes the project implementation and the performance of the system. In addition to a strong involvement and support of management, the very good acceptance of the operators has been facilitated by the remote access system that made it possible to immediately modify the system each time it was needed during the baby sitting phase. The system made it possible to increase gold production significantly through increases in tonnage and recovery thanks to a better control of the grind size through a stabilization of the secondary ball milling circuit and an improvement of the operating conditions of the classifying cyclones.

Jan 1, 2012

By G. H. K. Pearse, R. P. Taylor

The Big Whopper, one of only four giant economic rare metal pegmatites worldwide, is set to become a producer of the highly valued lithium mineral petalite (LiAlSi4O10) used in glass, ceramics and the specialty glass-ceramics familiar as Corningware® and the new ceramic stovetops. The deposit has a strike length of 1.5 km, a width of up to 80 m and a resource, open in all directions, of 11.6 Mt, grading 25% petalite. It is amenable to open pit mining and Avalon Ventures Ltd. holds a patent on a flotation process that produces an exceptional quality petalite product. The project will also produce: superb quality Na-feldspar which, too, finds use in glass and ceramics; the unusual Rb- K-feldspar for high voltage porcelain insulators; tantalum, in high demand for electronics; lepidolite, an ore of rubidium; and mica and tin. A positive prefeasibility study has been completed and it remains only to undertake bulk sampling and a full feasibility study.

Jan 1, 2001

By S. C. Tadolini, J. M. Goris, J. L. Gallagher

Cable supports offer several advantages over traditional secondary support methods by enhancing stress redistribution to pillars and gob areas, minimizing or eliminating timbers and cribs that reduce ventilation, eradicating material-handling injuries related to placement of crib supports, and providing a cost-effective alternative to secondary support. The U.S. Bureau of Mines (USBM), researching alternatives to traditional roof support methods, designed and installed high-strength cable supports to improve the stability of longwall gate road entries in a western U.S. coal mine. With the cooperation of industry, methods were developed to install and evaluate cable supports in a tailgate area using traditional resin cartridges. The cable-bolted areas successfully maintained roof support throughout the developed entries. Cable supports have replaced wood cribbing as secondary support in the bleeder entry system and have minimized or eliminated the use of cribbing in the longwall tailgate entries. This paper describes the theory, application, and advantages of cable supports and presents some mine measurements made to assess the cable performance during the retreat process of longwall mining.

Jan 1, 1999

This work illustrates the potential of two welding processes for joining AA1100-16 vol.% B4C metal matrix composite: laser welding process using a 4 kW Nd:YAG laser and Friction Stir Welding. A comparison is made between these two welding techniques in terms of microstructure and mechanical properties of welded joints. A large amount of brittle needle-like phases, together with some residues of B4C particles were observed in the fusion zone of laser welded joints. The use of Ti filler can improve the microstructure and increase the joint efficiency from 63% to 75%. On the other hand, the friction stir welding process being a solid state welding technique is interesting as it avoids the formation of brittle intermetallic phases. In addition, the breakage of B4C particles and the grain refinement of the matrix were observed in the weld zone. Consequently, FSW joints show much better mechanical properties than laser welded joints. Up to 100% joint efficiency can be achieved by FSW for annealed AA1100-16 vol.% B4C materials.

Jan 1, 2011

By K. Tada

A surface of a magnesium slab (hereinafter, referred to as Mg slab) or magnesium alloy slab (hereinafter, referred to as Mg alloy slab) becomes black with the use of conventional manufacturing methods. The methods also involve a danger that an explosion of the molten magnesium occurs through contact with cooling water. Thus, it has been impossible to produce a slab having a smooth surface. In the present method, a molten magnesium alloy is supplied into a mold, which is sheltered from the surroundings, from a pool in tundish, which is shielded from the surroundings. AZ31B slab formed in the mold is drawn horizontally out to the outside from an outlet of the mold by revolving of the pinch rolls. A cooling water is jetted at an acute angle onto the slab on the outer side of the mold outlet. Further, an inert gas is sprayed at the inner side of the mold outlet in order to seal in a gap between a free surface of the molten magnesium alloy and a sheltered board surrounding an upper surface of the mold. As a result, oxygen and droplets of the cooling water are prevented from running back to the mold side through the gap. AZ31B slab has a smooth surface condition and high quality without a gas porosity, a segregation or the like. Further, the slab has a size of a width of 100 to 120 mm, a thickness of 5 to 20 mm and a span of 10 m or more.

Jan 1, 2006

By M. A. Perras, H. A. Kasani, G. Walton

The development of an underground repository for the storage of spent nuclear fuel relies on a multi-barrier system to isolate the used fuel from the environment – ultimately, the biosphere. These barriers include engineered copper and steal canisters, dense bentonite, and the natural rock as well. In order to reduce the potential flow pathway along the excavation induced damage zone, various slots perpendicular to the excavation axis have been proposed. These slots are called cut-off seals and generally are filled with bentonite as it has high swelling potential and very low permeability. Many different geometries have been proposed, but clear guidelines on the selection of the optimum geometry have yet to be developed. In order to assess the optimum geometry, three shapes have been selected for this numerical study, including a trapezoid, a triangle, and a thin rectangular slot. The cut-offs were modelled for a conceptual shaft constructed in the Queenston Formation from Ontario over a stress to strength ratio that has been found at many underground research laboratories. It was found that the excavation of a triangular and thin slot cut-off had the smallest increase in the damage as quantified based on the extensile volumetric strain within the plastic yield zone. Both shapes showed an increase in the damaged zone by 13 cm at a stress to strength ratio of 2.75. The trapezoidal cut-off damage zone increased by 20 cm at the same stress to strength ratio. Further study is required to better define the optimum cut-off shape for wider variety of conditions and other geological formations.

Jan 1, 2020

By Hu Harries

WE RECENTLY completed a study for a client, who is an applicant to export gas from the Province of Alberta, on the effects of gas export on Alberta's economy. This study was part of the client's application ?before the Conservation Board, and, no doubt, some of you are familiar with it. Submissions by other applicants in earlier hearings before the Board and before the Royal Commission on Energy, as well as claims made by parties opposing export, have also brought forward a number of other opmwns regarding possible economic effects. Ali of these studies have been on a piecemeal basis. They have dealt with particular aspects of particular applications, and only indirectly and by inference with the overall question of gas ex-port. We have prepared this paper to review the overall picture and ex-amine, as far as time permits, all sides of the question. While the paper is entitled Economic Effects of Gas Export on Alberta, we felt that the area considered should in-elude northeastern British Columbia, not only because Westcoast, the first major gas export project, is essentially a northeastern B. C. project, but because this area has historically been, from the point of view of economic, if not of political, geography, part of Alberta. In this paper, when we talk of export, we mean export from the Province or, in this case, from Alberta plus northeastern B. C. Sales to other parts of Canada have exactly the same effect on the economy of this area as l1ave sales to the United States, provided, of course, they are made on equal terms.

Jan 1, 1958

By Xing-Liang Sun, Xian-Min Han, Zheng-Guo Zhu

The study on the material properties of frozen soils in China was being developed quickly in the past decades of years, because of the increase of the engineering constructed in frozen soil regions on the Qinghai–Tibet Plateau, and numerous research results were achieved mainly about strength and deformation behaviour and constitutive models of frozen soils. Studies have shown that the deformation procedure of frozen soils is irreversible; therefore, it is more appropriate to research mechanical properties of frozen soils by means of damage mechanics theory. In this paper, an elasto-viscoplastic anisotropic damage model is presented by introduction of Perzyna viscoplastic equation into analyzing the deformation of frozen soil. In addition, an anisotropic damage evolution equation is obtained by means of extending non-viscous damage to viscous damage. Triaxial tests at different strain rates are chosen to illustrate the application of this model, and good agreement between experimental data and numerically simulated results is obtained. The calculated results indicate that, under the same conditions, the damage at higher strain rate is less than that at low one. So the phenomena are explained from damage mechanics that the frozen soil has larger elastic modulus and shear strength at higher strain rates, and explained from mechanism that the emergence and development of micro-cracks in the body of frozen soil can be to some extent retarded at higher strain rates.

Jan 1, 2015