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By S. Castro, L. Gutiérrez, L. Uribe

"Use of lime in seawater as a pyrite depressant decreases Mo recovery in flotation of Cu- Mo sulfide ores. When technology that uses sodium metabisulfite (MBS) to depress pyrite is applied, the process is carried out at pH 6.5–7.5, the range where Mo recovery is higher than the usual pH 11.0–12.0 when lime is applied. Redox conditions and chemical reactions involved in depression mechanisms of pyrite by MBS, or sodium sulfite, in seawater are investigated and discussed based on the acidifying effect of MBS, oxidation of sulfite ions by dissolved oxygen, and the role of catalyst of some metal cations (e.g., copper ions) adsorbed on pyrite’s surface.RÉSUMÉ L’utilisation de chaux dans de l’eau de mer comme agent déprimant de la pyrite réduit la récupération de molybdène (Mo) dans la flottation de minerais sulfurés de Cu-Mo. Lorsque l’on applique la technologie utilisant du métabisulfite (MBS) de sodium comme agent déprimant de la pyrite, le procédé se fait à un pH de 6,5 à 7,5, gamme dans laquelle la récupération de Mo est supérieure au procédé habituel utilisant un pH de 11,0 à 12,0 lorsque l’on applique de la chaux. Les conditions de réduction-oxydation (redox) et les réactions chimiques impliquées dans les mécanismes de dépression de la pyrite par le MBS (ou sulfite de sodium) dans de l’eau de mer sont étudiées et débattues sur la base de l’effet acidifiant du MBS, de l’oxydation des ions sulfites par de l’oxygène dissous et du rôle de catalyseur de certains cations métalliques (par exemple les ions de cuivre) adsorbés à la surface de la pyrite. INTRODUCTIONThe copper industry is aware of the difficulties of floating Cu-Mo sulfide ores in seawater. Molybdenum recovery is partially depressed when lime is used to reject pyrite. In plant practice, sodium metabisulfite (MBS) has been demonstrated to be the most promising option for replacing lime in seawater."

Jan 1, 2017

By Jonathan Peck, Carl Hendricks

"Global Positioning Satellite (GPS) based positioning and navigation systems have been recently developed and implemented by AQUILA Mining Systems Ltd. on blast hole drills and electric cable shovels in Canadian open pit coal and iron ore mines. These systems enable the location of the drill bit or the shovel tracks to be accurately determined in three dimensions. The position of the drill or shovel is displayed to the operator via a real-time, Moving Map Display (MMD) on an LCD-VGA screen. The MMD allows the operator to accurately navigate the drill from blast hole to blast hole or maintain a desired shovel grade or face position, with respect to displayed bench features. The maps for the MMD are downloaded from the mine office via laptop or radio link as required or as mining plans change.To obtain reliable, accurate and real-time3D positions of mobile mining equipment, proven GPS technology has to be utilized. The GPS components need to operate reliably under the severe environmental conditions that exist on board mobile mining equipment. In addition, they have to contend with varying pit geometry’s and satellite configurations, with little or no performance degradation. These issues were initially examined in December1993 during a feasibility project between AQUILA and Gregg River Resources Ltd., in relation to implementing GPS systems on blast-hole drills.To achieve certain design objectives, AQUILA Mining Systems Ltd. has developed navigation systems for cable shovels and blast-hole drills based around off-the-shelf, high precision GPS components. These systems utilize the AQUILA Advanced Monitoring Platform (AMP), to display graphically, via the MMD, shovel grade and drill position to the operator to within ±12 inches of design coordinates. Production prototypes have been installed on a Marion 301 cable shovel and a Bucyrus-Erie49-R Series III drill at the Fording River Mine in August, 1995, at the Wabush Mine on a Bucyrus Erie 190-B shovel in June, 1995, and on a GD120 drill at Gregg River Resources Ltd. in January, 1996. All these systems have undergone field trials to test system components and functionality’s under actual production conditions. This paper will discuss these GPS-based positioning and navigation systems in subsequent sections."

Jan 1, 1997

By N. Romani, R. Provost

"Commissioning of a circulating dry scrubber plant was recently completed at an existing facility, in order to treat the sulphur dioxide off-gas emitted from rotary kilns. Proper planning of the different commissioning stages and staffing an integrated team are the most important factors required for a successful plant start-up. A strong operational readiness plan must be in place as early as the start of construction in order to ensure a smooth transition from commissioning to operations. Plant performance can meet or exceed performance criteria within the required timeframe if the proper group dynamic and good communication is established between construction, commissioning and operations teams.INTRODUCTIONCommissioning of a circulating dry scrubber (CDS) plant was recently completed at an existing facility in Quebec, Canada. The CDS plant treats the sulphur dioxide off-gas emitted from rotary kilns in order to meet increasingly stringent environmental requirements. This installation enables the existing facility to reduce their sulphur emissions by over 90%.The CDS ProcessA general overview of the CDS process is presented in Figure 1 below. The combined, de-dusted off-gas from multiple kilns is sent to the CDS, which acts as an entrained fluid bed, where the gas is contacted with a water mist, re-circulated solids and hydrated lime. The SO2 from the gas stream and the available calcium hydroxide (Ca(OH)2) from the hydrated lime dissolve in the water and react to ultimately form calcium sulphites and gypsum. The solid residue (referred to as CDS residue), is the primary byproductof the process.Fresh hydrated lime and CDS residue is captured by the dust collection system and is re-circulated to the CDS via a fluidised transport system. Clean off-gas passes through the dust-collection system and is then sent to the atmosphere by a single exhaust fan.The CDS residue purged from the system is combined with the dust collected from the kiln offgas system and this mixture is wetted in the already exiting agglomeration system, to minimize dust generation during handling, and then sent to disposal."

Jan 1, 2016

By Luis R. Fonseca, C. Raimat, C. Wendeler, A. Sanz

"Rockfall barriers are widely known as proven efficiency element to protect infrastructure by catching the rock blocks in the falling direction and absorbing the energy generated by them.It’s common in the project design phase and during installation, fix rockfall barriers for catch a high percentage of the falling blocks and in many cases consider as valid the solution when the barrier can capture all of them. However, in many cases it’s possible to consider the use of these protections, simply to guarantee a secure shed for the traffic and intercept simply the blocks that theoretically hit the road surface.The results of the high-energy rockfall protection barriers type GBE which protect GC-200 road in Las Palmas de Gran Canaria are shown in this paper.The topographic data should be especially detailed observed and even more if you want to apply the technique of ""shadow zone"" with a flexible gallery system. It should be drawn from detailed topographic maps and drawings (photogrammetric restitution) to the scales 1/1000, 1/500, or 1/200; and it is important not to ignore the presence of vertical cuts, tracks, small slopes that modify the trajectories (trampoline effect, hard points that favor the rebounds) and which are not always presented in the drawings.The ""shadow zone"" is defined as the protected area, located at a lower elevation to the line created by the rockfall barrier to except of trajectories of rocks and free from the influence of the deflection of the system under the maximum energy level for which it was designed (MEL)."

Jan 1, 2015

By Robert T. McKnight

"Traditional techniques for valuing resource projects companies have been primarily based on discounted cashflow methods (DCF) or by comparison to similar projects with an apparent market capitalization. Many resource projects are really forms of options to invest rather than a future cashflow stream. Employing the DCF method to value a resource project which is really an option to invest, can dramatically underestimate the real value of the project. The analytical tools required to evaluate options, while more complicated than the usual spreadsheets used for DCF, are becoming more easily available and usable by managers. This paper will discuss the background of options valuation and some of the tools which will make it easier for managers to estimate the value of projects and companies which have significant real option values.ResumeBob McKnight is a graduate of the University of British Columbia in Geological Engineering, supplemented by an MBA from Simon Fraser University. Following several years in the oil patch with Cities Service and Brascan, Bob returned to Vancouver in 1979 to work for Wright Engineers. He subsequently went on to work for Cassiar Mining, Getty Resources and Endeavour Financial before joining Pincock Allen & Holt Ltd. in 1998. His experience ranges from exploration to feasibility studies, financial evaluations of mining and oil & gas projects, due diligence, project finance, valuations and mergers and acquisitions. He has extensive international mining experience pertaining to such countries as Chile, Mexico, Uruguay, Thailand, Indonesia, Angola, Papua New Guinea, Kazakhstan.What are Options?Options have been around for centuries. They were familiar to Roman and Phoenician traders who were shipping cargoes from Mediterranean seaports. In the financial world, options are types of contracts that generally include the right, but not the obligation, to buy or sell a share, currency or commodity. The underlying commodity price or share price changes are assumed to be lognormally distributed. In this context, options are of two general types, ""call"" options and ""put"" options. Call options have the characteristic of having the right to buy a tradable commodity or currency at a predetermined price for a specified period of time. For the owner of call options, they become more valuable as the price of the underlying commodity increases. For the seller of call options, these options become an increasing liability as commodity prices rise, since there is the obligation to sell the commodity at a predetermined (perhaps lower-than-market) price. This characteristic of call options recently became high profile with the sharp rise in gold prices last year. The value of gold call options sold by certain producers increased their associated liabilities to the point where margin calls were made."

Jan 1, 2003

By Nancy E. Wilk

In 2015, more than 1.2 million deaths annually were estimated to be caused by occupational risks (WHO, 2018). In 2021, this estimate increased with the publishing of the World Health Organization (WHO) and the International Labour Office (ILO) Joint Estimates of the Work-related Burden of Disease and Injury based on data from 2000 to 2016 (WHO/ILO, 2021). These global estimates reported that each year 1.9 million people die from exposure to occupational risk factors, 81% of these fatalities resulting from non-communicable, occupational diseases. WHO/ILO notes that the health-related risk factors with the largest number of attributable deaths were exposures to long working hours followed by workplace exposures to particulate matter, gases, and fumes. The health outcome with the greatest work-related burden of deaths was chronic obstructive pulmonary disease, followed by stroke and ischaemic heart disease. In considering the 2021 data published by WHO/ILO, it is likely that the estimates are low and underestimate the true burden of occupational disease and injury. In support of that position, more recently the ILO estimated that “2.3 million women and men around the world succumb to work-related accidents or diseases every year; this corresponds to over 6000 deaths every single day” (ILO, 2022).

Jan 1, 2023

By E. W. Vekris

Patents are playing an increasingly important role in the business world. A diverse patent portfolio can enable a company to secure a monopoly within the market, which can provide a competitive advantage over competitors. At the same time, possessing a diverse patent portfolio greatly increases the value of a company's intangible assets. This paper provides an overview of the patenting process as it pertains to the fields of metallurgy and mining, and summarizes some general patenting strategies. A review of new "green technology" initiatives recently adopted by Patent Offices around the world is also provided.

Jan 1, 2011

By E. G. Gaylord

THE material improvements which have been made in the practice of exploiting oil and gas reservoirs in the United States during recent years may be attributed largely to: (1) The necessity for drilling deeper wells at costs not much greater than was formerly expended on shallower wells. (2) The necessity for producing oil at a lower cost per barrel. (3) A growing recognition of the importance of the nature of production practice upon ultimate yield of oil and gas. The first two of these factors result, to a large extent, from the fact that a greater proportion of new development has been deeper development, and these wells have been drilled in the face of progressively lower per well allowables. In California, for instance, maximum allowables have declined from 400 barrels per day in March, 1938, to 156 barrels per day in September, 1940, and during this same period some 125 wells were drilled to the deeper 10,000-foot producing horizons discovered during this time. The third item listed above results from our increasing knowledge of the basic factors which influence the amount of recovery we may expect from reservoirs. In addition to the longer-range planning now being undertaken by the more prudent operators, State proration and conservation laws have focused attention upon the importance of methods conducive to obtaining progressively greater quantities of the hydrocarbons in place. In a paper of this length it will be possible to discuss only a few of the recent advances. An effort has been made to select the more important of these and to indicate, where possible, the factors which have made these advances possible.

Jan 1, 1941

By Sergio Cattalanl, Francis Chartrand

"The geology and origins of volcanogenic massive sulfide (VMS) deposits in the Abitibi belt of northwestern Quebec have been the subject of discussion since the discovery of the Horne orebodies in Noranda in 1923.The present Noranda version of the VMS model characterizes the ideal deposit as a stratabound, base-metal accumulation that is in close spatial relationship with hydrothermal alteration and stockwork zones, felsic lava domes, coarse phreatic-pyroclastic breccias, and subvolcanic intrusions that characterize vent- and proximal{acies submarine volcanic environments. Deposits tend to occur in a favorable stratigraphic interval within a mining camp, and this is well-documented in the Rouyn-Noranda and Matagami camps.However, in recent years many VMS deposits have been shown to deviate from the ideal Noranda-type. For example, the Ansi/ deposit is characterized by sulphide-bearing alteration zones that extend far above the massive sulfide lenses, and by abundant magnetite immediately underlying massive sulfide. The Horne deposit appears to lack the typical chloritic alteration pipe underlying the massive sulfide lenses, as well as laterally-equivalent exhalite horizons. The Horne and Quemont deposits, besides being the two giants of the camp, are particularly rich in gold, whereas others, such as WaiteAmulet and Millenbach, have low gold values. Finally, some deposits in the Noranda camp, such as the Ansil, Corbet and Mobrun mines, are outside the favorable stratigraphic interval. Therefore, it would appear that part of the key to renewing base metal reserves in northwestern Quebec is the use of evolving descriptive-genetic models that incorporate geological variations like those cited above."

Jan 1, 1990

By Malcolm Scoble, Nick Vagenas, Greg Baiden

Recent advances in underground communications technology have demonstrated the feasibility of teleoperation and automation in underground metal mines. One major challenge lies in the automation of underground mobile machines from surface, with the potential to reduce significantly the need for human involvement in underground operations. This paper reviews the evolution of underground metal mining automation, principally related to the development of teleoperation and automation of mobile mining machines. Examples of prototype systems are given and the associated benefits that have been observed are reviewed.

Jan 1, 1997

By M. Dupuis

In the present study, the heat balance of the Hirakud smelter aluminium reduction cell has been accurately assessed using only a surface thermocouple and a pyrometer, As it is well known that using a single linear or quadratic relationship to estimate the heat flux from the measured surface temperature does not provide the accuracy required to close the cell heat balance, this approach was not used in this study, Instead, the fundamental natural convection and radiation heat flux equations were used systematically for each measurement point, Practically, this means that the ambient air temperature and at least one ambient radiative temperature must also be known in addition to the surface temperature for each measurement point. Sometimes, the radiative heat flux could not be accurately estimated using a single ambient radiative temperature, In those cases, a more accurate estimation based on two ambient radiative temperatures and corresponding view factors has been used instead, It turns out that although at least three temperature measurements are required to estimate a single heat flux, it takes a lot less time to make those temperature measurements using a pyrometer than directly measuring the heat flux using an expensive heat flux meter, Furthermore, no loss in accuracy was detected when using this approach as the cell heat balance could be closed within 5%, the level of accuracy typical of cell heat balance assessment using heat flux meter.

Jan 1, 2004

By Nehad Elsafty

It is always necessary to expand existing buildings, so that they could meet the growing societal needs. Compared with demolishing them and then constructing new ones, the expansion of existing buildings could not only reduce project cost, but also save the use of energy and raw materials in projects. Therefore, it is widely adopted in most under-developed countries. However, the expansion of existing buildings is not an easy task. It has been involved with a lot of issues in defining the scope of work, planning landscape, managing construction activities, etc. This paper investigates the potential challenges in expanding existing buildings. The project of expanding the Al-Agoza Hospital, one of the biggest and oldest hospitals in Cairo, Egypt, is selected as a case study. In the case study, the project documents have been carefully reviewed. The project engineers and the health-care professionals working in the hospital have been interviewed. This way, the point of views from the owner, the architect/engineer, and the contractor have been taken into account. Several lessons are learned through the discussion with these people. The results from this paper are expected to provide pieces of useful advice and suggestion for the expansion of existing buildings in the future.

Aug 1, 2013

By M. G. Beukes

"In South Africa most of the large gold mines operate between 1500m and 4500m below surface where reef is accessed initially through a vertical shaft system then via a network of tunnels and mined in either a longwall, sequential grid or scattered mining configuration. Due to the complexity of the ventilation networks used to ventilate these mines and the potential disastrous consequences associated with underground fires, it is of utmost importance that these mines are managed in such a way that underground fires are prevented. However, if they do occur the fires are managed to firstly prevent the loss of life and secondly protect the infrastructure and viability of the mine. The aim of this paper will be to: • Discuss current SA mining legislation regarding underground fire prevention and control. • Examine these fires from a risk management perspective by means of a bowtie assessment. • List and discuss the major Threats and Consequences as determined by the bowtie assessment. • Discuss the various prevention and consequence controls for deep level underground fires. • Examine how to effectively run an emergency control room. From this, a practical way of designing, implementing and managing an underground fire management system is explored. Lastly, the paper identifies new technology and ways of thinking and how these can be used to combat underground fires. INTRODUCTION The orebodies of South African gold mines are generally narrow tabular structures that vary in thickness between 0.8m and 1.2m with an inclination of between 200 and 700. This, coupled with depths of between 1500m and 4500m, as well as the unpredictable geology, creates unique challenges and significantly impacts on mine designs and mining methods. In general, gold bearing reefs are accessed initially through a vertical shaft system then via a network of tunnels and mined in either a longwall, sequential grid or scattered mining configuration (Figure 1). Mining is very labour intensive with very limited mechanisation opportunities and this increases the risk to human life if an underground fire occurs. On 16 September 1986, one of the worst mining disasters in SA mining history took place when 177 mineworkers were killed at Kinross Mine. An acetylene tank sparked flames that swept through the mining tunnel igniting plastic covering on the wiring and the flames also set fire to polyurethane foam. The burning plastic combined with polyurethane and the toxic fumes that filled the shafts caused the miners death. This incident was a stark reminder of the serious consequence that underground fires can have on human life as well as the crippling financial and asset impact for the mining companies. Over the past thirty years, the SA mining industry reduced the number of mine fires significantly by replacing normal timber support with fire retardant treated timber, alternative support systems such as backfill and elongate support and many other fire prevention initiatives. Although the number of fire incidents and number of fatalities due to fires does not show a direct correlation because of various factors, the controls put in place against fires has had an impact on the number of fire and explosion fatalities (Figure 2)."

Jan 1, 2019

By Gaston Gendreau, Marcel Allard

"Sidbec-Normines Inc. est une société formée de trios partenaires soient: Sidbec, British Steel Corporation et la Compagnie Minière Quebec Cartier. L'objectif de l'opération minière est d'exploiter à ciel ouvert le gisement d'hématite spéculaire de Fire Lake et de produire au concentrateur de Lac-Jeannine, près de la ville de Gagnon, 6 million de tonnes de concentré pour alimenter l'usine de bouletage de Port Cartier.Le présent exposé a pour but de fa ire ressortier les caractéristiques d'une opération dont la mine est située à plus de 100 km du concentrateur, d'en faire ressortir les particularités touchant le transport du personnel et du minerai. En plus, on traitera de l'importance dans une telle situation d'une organisation efficace dans la gestion des services et de l'opération (atelier, concasseur, entrepôt, etc.).IntroductionSidbec-Normines Inc . a entrepris l'exploitation minière du gisement de Fire Lake, le 1er janvier 1977. Le but de l'entreprise est de produire annuellement six millions (6 000 000) de tonnes de concentré d'hématite (oxide de fer) titrant 66% Fe au concentrateur de Lac-Jeannine a partir d'un minerai d'une teneur moyenne de 33% Fe, extrait de la mine de Fire Lake. Ce concentré est ensuite achemine à Port-Cartier et alimente I'usine de bouletage.Les installations minières de Sidbec-Normines sont situées a trois endroits différents : la mine à Fire Lake, le concentrateur à Lac-Jeannine et l'usine de bouletage à Port-Cartier. La mine de Fire Lake se situe à 83 km de la ville de Gagnon et à 100 km du concentrateur de Lac-Jeannine. Une route provinciale relie la ville à la mine et au concentrateur. Le minerai est acheminé de la mine au concentrateur par chemin de fer et le concentré est transporté par train sur une distance de 309 km à l'usine de bouletage de Port-Cartier."

Jan 1, 1982

By Maurice Hall Haycock

ONE result of the higher price of gold has been the exploitation of many low-grade deposits, the successful treatment of which depends upon obtaining high recovery of the contained gold. Modern methods have made it possible to recover gold from many ores formerly regarded as impossible to treat economically, but in order to apply these methods efficiently it has become desirable, and indeed in many cases indispensable, to gain precise information concerning their mineralogical and physical character. The most successful means of doing this is the use of the reflecting microscope. Reflecting microscopes had long been employed by metallurgists for studying polished surfaces of iron and steel when, thirty years ago, Dr. W. Campbell, of Columbia University, advanced the idea of using similar methods for studying opaque minerals (1). The immediate result was the completion of two microscopic studies, the first on Cobalt silver ores (2) and the second on Sudbury nickel ores (3). The idea was surprisingly slow in being adopted, and not until 1911 did it begin to spread through the universities of this continent. From then on, ore microscopy, or 'mineragraphy', made rapid progress, and, during the next fifteen years, research in universities of North America and Europe led to the development of somewhat specialized apparatus and technique. This phase of development, which resulted largely in contributions of a descriptive nature, furnished a mass of data from which the possibility of economic applications was soon recognized. Ore microscopy became an aid to the mining geologist in solving many problems of ore deposition. This soon led to its application in the study of ores and mill products in connection with their treatment. Its usefulness in this latter field has been very marked and has led to its widespread adoption by the mining industry.

Jan 1, 1937

By A. Burduk

The traditional approach to managing information flow between a mine underground and overground, applied in copper mines of KGHM Polska Miedz S.A., is mostly based on exchanging spoken information using the mine telephone network and printed documentation. This way of information flow significantly influences effective use of time of a shift foreman employed at a mining division. In order to minimise multiplication of significant information generated as paper documentation, a concept of an IT system module to input basic data concerning operation of the mining division was developed. The idea is based on computer software that permits inputting data in the underground and their immediate sending to the overground. The above-mentioned solution will permit significant reduction of administrative work time that each foreman has to do on each shift. The time saved on filling forms and communication will permit the foreman and the other workers involved in information flow to spend more time for execution of their basic duties. In the case of the supervision employees working in the overground, the IT system will allow all the interested persons to be informed directly, with no necessity to transfer the information on the situation in the given mining division by turns from one to another. On the other hand, saving time on administrative works will permit the foreman employed in the underground executing more detailed inspection of workplaces in his subordinate mine division. Thus, availability of the foreman for the mining division operation will be improved. KEYWORDS

Aug 1, 2013

By F. Habashi

The pioneer work on pressure hydrometallurgy was conducted in Russia at the end of the nineteenth, and the beginning of the twentieth centuries, by Karl Josef Bayer (1847-1904) and Vladimir Nikolyevitch Ipatieff (1867-1952), both working independently in Saint Petersburg. Bayer was studying pressure leaching while Ipatieff was studying the precipitation of metals and their compounds by hydrogen under pressure. Gradually, industrial applications took place first in the aluminium and later in the nickel industry. Today, the technology is well established in a large number of industries, such as uranium, gold, zinc, titanium, tungsten, and more recently copper.

Jan 1, 2004

By J. E. Ryan

General Description Due to the extreme cold weather experienced in Flin Flon during the winter months, thought and precaution were necessary in the design of the plant buildings. The machine shop, carpenter shop, drill shop, and coal plant buildings are similar in the building materials used in their construction. They are sided with two-inch shiplap, insulated with celotex and asbestos paper, and covered with corrugated iron on all side-walls. Roofing consists of 2 by 4 lumber on edge, laminated, and further covered by celotex and three-ply roofing. These buildings are heated by means of unit heaters. The heaters are primarily steam-heated radiators, through which the air of the buildings is circulated by electrically-driven fans. Our machine shop is located to the east of, but central to, the main operating buildings of the mine and plant, and is so connected by a net work of tracks as to be able to serve all portions of the entire plant conveniently. The building is divided into two bays, the main bay 53 ft. by 340 ft., and the east bay 24 ft. by 340 ft. The shop office and drafting room, a two-story annex 24 ft. by 30 ft., is located on the west side of the shop. The arrangement within the shop is such as to house conveniently the several departments, namely, heavy machine tool section, repair floor section, boiler shop heavy tool and floor section, blacksmith heavy tool and forge section, tool room, electric welding rooms, stock room, tin and copper shop, and electrical parts and armature winding and repair shop (see Figure 1). All the heavy tools, the repair floor section, and railway tracks are so located in the large open bay as to be fully serviced by an electrically operated 15-ton bridge crane, with a span of 50 feet and a travel the full length of the shop. A standard-gauge railway track, branched off the main line, penetrates the full depth of the building. This track lies along the extreme east side of the main bay, allowing easy entrance and movement of rolling stock and heavy machinery, loaded on standard flat-cars, to the repair floors in the main bay. Eight jib cranes, affixed to building columns, further facilitate the heavy repair work throughout the various shop divisions. Our light and heavy machine tools are standard equipment, not unlike tools used in mine, mill, and railway shops.

Jan 1, 1935

By A. Hartikainen, M. Rinne, F. Johansson, R. Yorke, L K. T. Uotinen, E. Korpi, J. Antikainen

"In order to determine the in-situ shear strength of rock joints, large scale testing is required. However, this is both expensive and difficult to execute. One possible method to overcome this may be to use photogrammetry to capture large joint surface roughness in-situ and downscale it to replica samples, which could be sheared in laboratory. In this paper, as a first part in such a method, a technique to digitize surface roughness and to produce replica samples for laboratory shear testing from a larger joint sample are presented. First, a thin granitic rock slice with dimensions of 1.75 m x 0.95 m of granitic intact rock was chosen for the study. The joint surface is fresh and created through tensile induced splitting. The large joint sample is digitized using photogrammetry. Then, one fullscale 1.7 m x 0.6 m geometry is cropped from the digitized joint geometry and then subsamples at 10x, 7.5x, 5x, 2.5x and 1x scales. All sub-geometries are scaled down digitally to produce 0.17 m by 0.06 m geometries. The geometries are used to make casting molds both positive and negative to produce samples with perfect matedness. The casting molds are 3D printed in polylactic acid plastic and C60/75 concrete is cast to produce a replica series. In addition to the creation of this replica series, two pilot replicas are also tested using a portable shear box with a 0.5 MPa normal pressure. The results from the pilot rounds are presented and discussed. Finally, suggestions for future research are given.INTRODUCTIONThe rock mass strength is in many cases controlled by the shear strength of rock joints, especially in hard rock masses. The shear strength is generally found to be influenced by several parameters, including normal stress, the basic friction angle of the intact rock, the joint surface roughness, the joint wall compressive strength, the matedness of the joint surfaces, weathering and infilling. The effect of these parameters for the joint shear strength can be evaluated in laboratory scale. However, the shear strength is known to be scale dependent. How the scale effect influences the strength is not fully understood. The general consensus is that the shear strength decreases when sample size increases, i.e. a negative scale effect (Bandis et al. 1981). However, some studies have presented contradictory results, see for example Hencher et al. (1993) and Kutter & Otto (1990). The extent and nature of the scale effect is still a question of debate (Tatone & Grasselli 2013)."

Jan 1, 2015

By P. Bramwell, R. Tremblay

"The Port Radium leaching plant of Eldorado Mining and Refining, Limited, produces 450 t./d. of sulphuric acid leach liquor containing l. 73 g. /I. U 308. After solvent extraction, the waste solution is discarded at 0.002 g./l. U30s for a recovery of 99.8 to 99.9 per cent. The solvent is acidified with weak sulphuric acid, loaded to 4.5 g./l. U80:1 in three-stage extraction, scrubbed with water, and stripped with soda-ash solution in single-stage stripping. Caustic removes the UaOs from the pregnant strip solution as a precipitate. The slurry is filtered, re-pulped with water, and re-filtered. The pressed precipitate at 81 to 82 per cent equivalent U30s is dried and packaged. The carbon-ate filtrate is cooled to remove sodium sulphate build-up and carbonated to convert excess caustic. Reagent consumptions are 4.1, 0.22, and 0.39 pounds per 1,000 gallons of pregnant solution for Diesel oil, amine, and alcohol, respectively. Caustic consumption averages 1.3 to 1.4 pounds per pound U3O8.Extraction and stripping is accomplished in sheet-iron mixer-settlers lined with Phenoline. Piping on both circuits is Schedule 80 polyvinyl chloride. Valves are straightway Buna N lined with American Hycar diaphagms. Extensive instrumentation ensures good metallurgy with a minimum of variations and labour. Mixing in a continuous organic medium and careful acidity control are required to minimize third-phase formations. Heating the precipitate slurry is conducive to good filtering in Perrin presses with neoprene-coated, rolled-steel sectors. Sodium sulphate is crystallized from carbonate filtrate solution by batchwise cooling to 54°F. with lake water."

Jan 1, 1959