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By A. Montini, M. H. Moys

"A conductivity probe mounted in the shell of the mill has been used to measure the behaviour of the load in the mill as a function of operating variables. It was found that certain properties of the conductivity signal correlate strongly with the per cent solids of the slurry passing through the mill; in particular the angular location ?D of the shoulder of the load is an increasing function of the per cent solids. A method for measuring the viscosity of the pulp discharging from the mill has also been developed. The use of the measurements in mill control is illustrated by simulating various control strategies for open circuit milling. It is shown that the use of ?D allows very tight but imprecise control of the slurry rheology in the mill, while the use of viscosity is subject to severe limitations in speed of response. A cascade control system involving both measurements provides adequate control of slurry rheology within the mill. Applications to closed circuit milling are discussed.IntroductionMultivariable control of milling circuits continues to receive a lot of attention in the literature. Hulbert and co-workers and Niemi, et al. have described the use of Inverse Nyquist Array (INA) techniques while Herbst has recently described the use of Optimal Control. It is significant that in neither of these three projects was any variable associated with the grinding mill itself (e.g. power or properties of the mill discharge) used in the control strategy. Pauw, et al.do, however, use mill power in their multivariable peak-seeking controller for pebble-mill control. Little work has been published on the use of measurements of the properties of the slurry being discharged from grinding mills, in spite of the fact that milling efficiency is known to be strongly affected by slurry rheology».Moys has recently developed a technique for measuring the dynamic behaviour of the load in the grinding mill. This method involves the monitoring of the response of a conductivity probe mounted in the shell of the mill which gives a measurement of the orientation of the load inside the mill. It was found that the load behaviour was strongly influenced by slurry rheology. In this project a technique was also developed for the measurement of the viscosity of the slurry in the mill discharge. It was, thus, decided that it would be worth investigating the use of these measurements in mill control schemes since direct control of the slurry rheology in the mill must inevitably increase the efficiency and productivity of the grinding circuit as a whole.This will be done by using the dynamic responses measured by Moys and Montini to simulate the behaviour of an open circuit ball mill. While the control of open circuit mills is of little interest, this simulation provides a simple but powerful demonstration of the advantage provided by these measurements, advantages which should apply to closed circuit operation of any mill type (including autogenous milling). Investigations into multivariable control of a closed circuit ball mill are currently nearing completion and will be published soon."

Jan 1, 1987

By Dennis V. Woods, J. Duncan Crone

"In order to determine its capabilities and to aid in the interpretation of fie ld results, a scale model study and field tests were carried out on the Crone borehole pulse electromagnetic (PEM) system. The model results indicate that if a borehole passes in the vicinity of a tabular conductive body, the system will not only detect the presence of the body, but will also return information as to its conductivity-thickness product, size, altitude and position.The effect of variation of these electromagnetic and geometric factors on the shape of the response curve from a borehole PEM survey is displayed by a number of suites of scale-model response curves. These model curves can be used directly as type curves in the interpretation of field results. Field tests of a prototype PEM system provide a check on the scale-model results and also summarize the procedure of interpreting field data using the model type curves.The borehole pulse EM system can be effectively used as a follow-up geophysical instrument for locating and delineating known conductive bodies. It can also be profitably utilized as a primary geophysical exploration tool in areas of deep mineralization below the depth limit of conventional airborne and ground geophysical systems. The probed area of a diamond drill hole in these cases is increased from a 1- inch drill core to a zone extending hundreds of feet from the hole."

Jan 1, 1980

By James Kear, Romain Prioul, Robert G. Jeffrey, Andrew P. Bunger, Dimitry Chuprakov

"Unconventional gas and geothermal reservoirs are typically naturally fractured and therefore the challenging problem of hydraulic fracture (HF) growth through naturally fractured rocks is an important issue especially for the development of accurate predictive HF models. This paper presents results from laboratory experiments in which HFs have been created in both sandstone and crystalline (gabbronorite) rock specimens such that they impinge either orthogonally or at an oblique angle on an unbonded, machined frictional interface. Depending on the conditions of each experiment, the fractures either cross or are blunted at the interface. The growth behavior was ascertained for these experiments based on a synthesis of the injection pressure record, active ultrasound monitoring, and direct post-experiment inspection of fractured specimens. From these experiments we observe: 1) A contrast between direct crossing and crossing with an offset for orthogonal and oblique intersection, respectively, 2) Apparent independence of crossing/blunting behavior on the friction coefficient for orthogonal intersection, 3) Dependence of the stresses required to promote crossing on the intersection angle between the HF and NF, 4) Existence of cases in which the hydraulic fracture crosses but then essentially ceases propagation such that all fluid is diverted to the interface. INTRODUCTIONHydraulic fracturing is a vital technology used to increase the productivity of oil, gas, and geothermal wells. Predicting hydraulic fracture (HF) growth is, in turn, critical to design of hydraulic fractures that grow to the desired length, accept the desired amount of proppant, and remain contained in the reservoir without unwanted height growth into surrounding layers (e.g. Economides and Nolte, 2000). The importance of HF modeling has prompted 6 decades of research during which simulators have become more efficient, more accurate, and have addressed a growing range of complexities (see review of e.g. Adachi et al., 2007).One of these complexities is the interaction between HFs and mechanical discontinuities such as natural fractures (NFs). Efforts in this area have been mainly driven by development of unconventional (i.e. low permeability) oil and gas resources because essentially all viable low permeability reservoirs, including shale gas/oil reservoirs, are naturally fractured to some degree (King, 2010). One of the most important questions for developing effective HF stimulation strategies in these reservoirs is whether the hydraulic fracture(s) is/are expected to be single-stranded or whether interaction with the NFs will lead to network-like growth. The basic building block for numerical simulators that can address this question (such as Kresse et al., 2013 and Weng et al., 2014) is whether an HF that intersects an NF will cross the NF or whether its growth will be captured by the NF so that additional fluid injection pressurizes the NF but does not generate ongoing growth of a new HF. These scenarios, including subcategories such as crossing with an offset, have been recognized for several decades (Daneshy, 1974; Warpinski and Teufel, 1987, and as recently reviewed and expanded by Chuprakov et al., 2013)."

Jan 1, 2015

By H. Utsunomiya, J. Su, K. S. Tamimi, S. Yue, M. Sanjari, L. Kestens, A. S. Kabir, R. Petrov

The recrystallization and texture evolution of AZ31 sheets obtained through two stages was investigated at different stages of post-rolling annealing. The specimens were rolled at the temperature of 100? and at a fast speed of 1000m/min and low speed of 15m/min with a reduction of 30% in one pass. The results show thatAZ31B sheets rolled at 15 m/min and 100 °C has fractured for reductions of more than 30% per pass. However, by increasing the rolling speed to 1000 m/min the rollability was improved significantly and the material can be rolled to reductions of more than 70% per pass. The high speed and heavily deformed materials are fully recrystallized even at 100 °C.

Jan 1, 2015

Keeping the sediment on the mine site and out of the water course is essential from the regulatory, environmental and sustainability perspectives. Regulation of this aspect of mining is embedded in environmental legislation and government receiving water quality standards, and government control has apparently been considered to be the most appropriate method to define mine site discharge standards and the environmental implications of sediment in downstream watercourses. A literature search for guidelines for the site specific design and operation of sediment ponds treating mine site runoff to remove total suspended solids, turbidity and flocculant-induced toxicity, revealed little information on the mining industry?s and government?s roles in defining the ?how to achieve? related to sediment pond design. Is there a need or reason for an industry-driven leadership to clearly define the ?how to? keep the sediment on the mine site and out of the water course? Currently, this issue is addressed in Canada by a federal mining regulation for metal mines which specifies discharge quality for sediment. This paper focuses on the method used in British Columbia, Canada, to regulate and provide a scientific methodology to control the discharge of sediment from mine sites. Management plans relative to this topic are discussed and are considered to have value from the exploration, construction, operation and the onset of closure phases. In addition, the balance and linkage between the erosion control management plan and the sediment pond management plan are discussed in terms of how they may be designed to complement each other to lower the risk of exceeding discharge and receiving water quality standards. If there were an industry-driven standard, or guidance document relative to addressing sediment release, it would benefit mining companies by eliminating the repetitive analysis of this topic for each new mine, mine expansion, and mine modification; also, government may often replace certain aspects of permitting with a regulation, if there is a government/industry established standard defining Best Achievable Technology (e.g. the Canadian Metal Mining Effluent Regulations).

Aug 1, 2013

By C. Schmidt, M. Kohnk, C. Siemers, J. Kiese

The application of conventional titanium alloys is limited to 550°C due to their poor oxidation resistance. In addition, severe grain growth is observed in single-phase titanium alloys in long-term runs at elevated temperature leading to a degradation of their mechanical properties. In exhaust applications in automotive or aerospace engineering, products are often manufactured by cold-deformation like deep-drawing or rolling which is normally difficult in oxidation-resistant titanium alloys due to the presence of titanium-silicides. Therefore, in the current study, titanium alloys based on CP Titanium Grade 1S (soft grade) were developed showing (1) improved oxidation resistance due to a concerted addition of silicon, iron and niobium, (2) microstructure stability by the precipitation of hafnium-silicides mainly on the grain boundaries and (3) good cold-deformation properties. The industrial production route was developed so that the new class of Ti-Si-Fe-Nb-Hf-alloys is now ready for application in exhaust systems of planes or cars at minimum 800°C.

Jan 1, 2015

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By Deni Pageau, Deni Caron

"This paper describes the operations of the open pit and emphasizes particular aspects of Les Mines Selbaie. The open pit as well as its related services were incorporated into a complex which includes an underground mine and a concentrator. The equipment was chosen with the objective of auto-sufficiency during each phase of mining. The paper outlines the organization and the methods used in each step of mining, notably: drilling, blasting, loading, transporting and crushing. The responsibilities of the Engineering Department are also outlined from the conception of the open pit to the latest follow-up methods. A short resume of the results which have been obtained as well as suggestions for improvement are provided.Layout in Consideration of Main SiteThe A-I zone deposit is located I km from 8 zone. Open pit mining of A-I zone required the regrouping of different services to those already existing.I. The crusher was placed in an area close to the concentrator in order to minimize the length of the conveyors and to provide space for the crushed ore reserves (50000 tonnes).2. The location of the service building (warehouses, mine offices, maintenance, engineering and geology) raised a few problems. Because of the multiple services provided therein , it was impossible to fulfill all the requirements, and the garage in itself is located a fair distance from the pit. Added to this inconvenience is the fact that heavy equipment regularly travels throughout the main yard.3. The storage of explosive magazines has been changed to obtain more surface space and meet government regulations.4. A space has been provided for minor repairs in the garage used during exploration. A trailer was installed next to the garage to provide a lunch room for the employees working at the open pit."

Jan 1, 1990

By G. J. Reid, D. H. Stewart

"A diversity of structures and rock types in the Aft on pit has resulted in the occurrence of several different types of wall failure. Delivery of ore to the mill has not been affected and safety has not been compromised thanks to effective remedial 1V0rk and to a system of structural mapping, back analyses of failures, groundwater monitoring, and simple movement monitoring. Remedial measures have included artificial support, dewatering (including vacuum-assisted drainage), flattening of slopes and temporary buttressing. This paper describes six different wall failures at Afton and highlights the features of each. Examples given include rates of movement, extent and direction of movement, and piezometric responses. The practical, low-cost monitoring system was sufficient in one case to allow the prediction of date of failure. IntroductionThe Afton copper deposit is located 13 km west of Karnloops, British Columbia and has been mined for nine years out o f an expected eleven-year life. Open pit mining has reached 700 feet below sur face and is designed to proceed to 970 feet below surface by the time the pit is completed. The excavation is in a structurally and lithologically complex environment. Inevitably, some wall failures have occurred but these have been limited to small, manageable failures which have not compromised production or safety. To handle the failures it has been necessary to understand their nature. Of prim e concern has been the rate s of movement, but displacement vectors and hydrology have been monitored as well. The monitoring system is based on EDM surveys and on wire extensometers and plates set across cracks. Water levels have been read in standpipe piezometers. At Afton the emphasis has been on simple, practical, and inexpensive monitoring and because rock type s and structures play such a major role in any failure, detailed geologic al mapping is carried out."

Jan 1, 1988

By Robert Voisey, Robert J. Spencer

"LynnGold's MacLellan Mine is located about 8 km south east of Lynn Lake immediately to the east of the Keewatin River (Fig. I). The property is accessible by an all-weather road, leading north from the provincial highway 391, which links with the Town of Leaf Rapids and the City of Thompson to the south.The ore body, as outlined in the original feasibility study, is expected to produce in excess of 9.3 x IQ6 gm of gold and silver over the next 5 years. However, the deposit is open to depth and exploration is continuing on and around the main zone and the many satellite deposits.The start of construction of the MacLellan Mine and mill was scheduled to phase in with the closure of the Fox copper-zinc mine located 48 km west of Lynn Lake. The majority of the employees from the Fox Operation were either employed at the MacLellan Mine or relocated to Sherrin's Ruttan Operation.GeologyThe MacLellan gold ore deposit is located on the northern section of the Lynn Lake Greenstone Belt known as the Rainbow Trend. This Trend is a 40 km gold bearing rock sequence extending both east and west from the MacLellan Mine. The southern section of these two east-west trending structures is known as the Johnson Shear, this is also gold bearing."

Jan 1, 1990

By D. F. Hambley

"In designing are passes f or underground mines specific consideration should be given to unimpaired flow of broken rock, the dump point, and typical practices f or overcoming operational difficulties. Design features such as branches, bends, and knuckles should also be considered. This paper pro vides engineering information and various criteria for designing are passes, draw points. feeders, and support systems, together with several illustrative examples.IntroductionOre passes are the primary mean s o f vertical transfer of mined ore to the ore bins and loading pocket from which the o re is hoisted to the surface (Fig. 1) . While the words "" ore"" and ""ore pass"" are used here, such transfer systems ca n be used for any broken rock.The most extensive ore pass systems are found in caving and sublevel stoping mines. Extensive ore pass systems are also found in multilevel mines having steeply dipping orebodies. In more flat-lying orebodies , ore pass systems are sometimes used in conjunction with conveyor systems .Two decades have passed since the principles of the flow of bulk solids were formulated (Jenike, 1961, 1964; Johanson and Colijn, 1964; Kvapil , 1965). However, few published papers are available that discuss the design criteria for ore pass systems. Therefore, the aim of this paper is to provide the information necessary for good o re pass design .Rock Flow in Ore Pass SystemsIf an ore pass system is to fulfill its function, the transfer o f material must occur in an orderly fashion and in such a way that the full size of the opening is employed effectively. Apart from un controlled flow at the drawpoint, or outlet , whose design will be considered later in this paper, two occurrences may impede flow in an ore pass, namely:• Hangups due to interlocking arches.• Hangups due to cohesive arches.Prevention of each of these problems will be discussed in succeeding sections of this paper. A third problem piping, is related to the ratio of the drawpoint size to the o re pass size and will be discussed under drawpoint de sign."

Jan 1, 1987

By S. A. Ghoreishi-Madiseh

Underground mines, with their relatively high ground temperature and their extensive backfilled stopes provide a great opportunity for producing geothermal heat. The novel idea of installing a network of heat exchange tubes into stopes prior to backfill placement converts each mine stope into a heat producing battery. In this system, backfill plays the role of the heat exchange medium conducting heat from the surrounding rockwalls to the heat exchange tubes. This geothermal heat can be used for heating: mine facilities and buildings, the intake air, a close-by mineral processing plant, or even nearby communities. This paper investigates the possibility of extracting renewable geothermal energy from backfilled mine stopes by means of closed-loop geothermal cycles. To simulate realistic operational conditions a heat transfer model is developed and solved numerically. To evaluate the numerical results, a small scale physical model is constructed and the experimental results are compared with the simulation results. The study estimates the sustainable rate at which heat can be extracted from a typical underground mine stope, the resulting outlet temperature and performance of the geothermal system. The results show that mine stopes are capable of sustainably producing geothermal heat not only when the mine is active, but also after the depletion of the ore body. Therefore, an underground mine will no longer be perceived as an enduring economic liability, but as a long-lasting source of clean, renewable, and inexpensive low-grade geothermal heat.

Aug 1, 2013

By Oliver Hall

WITH the friendly consent both of the Institution of Mining and Metallurgy, for whom this paper was written, and of the author, we had the pleasure of publishing Mr. Oliver Hall's paper on Mining at Noranda in our issue of last March and of having Mr. Hall present it at the Montreal Meeting. In the following pages we now report the discussion elicited by the paper at a meeting of the Institution in London on March 18th. The report is taken from the April, 1937, issue of the Bulletin of the Institution, to whom we again tender our thanks. THE PRESIDENT (MR. ROBERT ANNAN) said that this paper was, by arrangement with the Institution and the author, also being published by the Canadian Institute of Mining and Metallurgy for approximately simultaneous discussion. He was sorry that Mr. Oliver Hall could not be present to introduce it in person, for he was sure that the author would have had many more details to give about this most interesting mine. The paper contained a very useful account of mining operations, and personally he had been pleased to see the tri-dimensional projections of the orebody in Figs. 3 and S. It was a good illustration o the value of that method in presenting the form of an orebody such as this. While he had no desire to go into technical details, he wished to call attention to a remark in Mr. Hall's introduction, in dealing with the history of the mine and the principles on which it was run. The author had given an account of the early difficulties in solving geological problems, and later of the economic difficulties of seeing this mine through a period of intense depression in metal prices. He stated that it was clear that, to maintain income, tonnage must be increased, and, to maintain profits, costs must be decreased. It would be observed that there was no question of increasing the grade of ore. Then the author went on to say: 'Having set the house in order in the years of adversity, the higher price for gold is being used to mine to still lower limits and lengthen the life of the enterprise and the welfare of those dependent on it'.

Jan 1, 1937

By D. Jean Hutchinson, Mark Diederichs

"Cable bolts are an important support component in modern underground mines. If an optimized cable bolt system is to be achieved, it is insufficient to focus on cable bolt layout design or on cable bolt installation in isolation. Cable bolt support, like all engineered systems, requires a holistic approach, encompassing integrated elements of design, implementation and verification. The “Cable bolting Cycle” described in this paper incorporates these components along with related tools and procedures which should be used together to ensure effective and efficient cable bolt support.Design involves the consideration of demand, capacity and constraints as outlined in this paper. The demands imposed on the sup-port system by the rock mass response to excavation under the combined action of stress and gravity must be matched to the capacity of the cable bolt array. The cable bolt system capacity is a function of the component strengths of the steel strand and the bond (load transfer) and by the deformation response and retention characteristics of the system. The design is bounded by operational and economic constraints.Implementation of the cable bolt array can then proceed and must include appropriate protocols of communication, training and quality control, in addition to both general and site specific installation procedures. Implementation will be discussed as the sum of these components.Implementation of the cable bolt array can then proceed and must include appropriate protocols of communication, training and quality control, in addition to both general and site specific installation procedures. Implementation will be discussed as the sum of these components.The information presented in this paper represents a very abbreviated version of much broader concepts, procedures and design charts, presented in a practical cable bolting handbook by Hutchinson and Diederichs (1996)."

Jan 1, 1996

By Jack Parker

"The original design of mine openings and pillars at White Pine was based upon traditional assumptions; i.e., that the principal load is due to the weight of overburden, and that horizontal stresses are equal to one-. third of the vertical.Beginning January, 1964, borehole deformation measurements confirmed suspicions that the principal stress is horizontal and several times greater than the vertical.Vertical stress appears to be directly related to depth, but lateral stresses vary considerably in direction and magnitude. The direction of major principal stress lies parallel to the bedding and is apparently parallel to tension joints. Lateral stresses appear to originate from an igneous intrusive.Mining induces stresses which add to the primitive stresses, in some areas precipitating failure. In this paper, rock failures are illustrated, methods of measurement and typical results are given, and measures to counter or utilize the lateral stresses are described."

Jan 1, 1966

"Pilot plants for pressure hydrometallurgy represent special design and project execution challenges. Over the past twenty years, Zeton has designed and fabricated a variety of world-class pressure hydrometallurgical pilot-plant facilities, and this paper discusses design considerations and strategies related to such projects. Project execution methods are also discussed, and guidance is given for the selection of materials of construction and for the selection of appropriate pressure and temperature design points for pressure hydrometallurgical pilot equipment. The paper concludes with a discussion of the need for process similarity with future commercial operations and the realities of pilot-scale equipment.INTRODUCTIONThe process technology developer or owner and the designer/fabricator of a new pilot-plant facility are faced with some difficult technical choices even after the decision to build a dedicated plant has been taken. A pilot-plant project is usually on the critical path of a large commercial project involving investments many multiples greater than the capital cost of the pilot plant. Schedule savings in the design, manufacture, and commissioning of the pilot plant or in a rapid completion of the experimental program can be disproportionately beneficial to the overall development project. However, inappropriate shortcuts resulting in major oversights can be disproportionately problematic.A number of considerations and suggestions for both the project execution approach and the process engineering design of pressure hydrometallurgical pilot-plant facilities are presented as a guide for potential owners and operators of new pilot-plant equipment and facilities."

Jan 1, 2012

By A. B. Baldwin

"Uranium and thorium mineralization occurs at several localities in eastern Quebec along the north shore of the Gulf of St. Lawrence. The main occurrences are near Sept-Iles, Baie Johan Beetz, Romaine and St-Augustin river. Mineralization occurs mainly as disseminated uraninite, uranothorite, uranothorianite, monazite and minor zircon and allanite. Yellow to orange oxidation products are observed along fracture planes of the uranium-bearing deposits to a depth of a few feet. Magnetite, biotite and smoky quartz have a distinct tendency to accompany the radioactive minerals. The host rocks include white to pink pegmatite, pink granite and also, in the case of the Romaine and St-Augustin River occurrences, cream to grey plagioclase-rich, well foliated paragneiss and migmatite. Radioactivity near secondary structures, such as fractures and joint planes, indicates some reconstitution of radioactive minerals.The North Shore of Quebec is the northeast extension of the Grenville sub-province. It is also a uranium-thorium metallogenic province."

Jan 1, 1970

By P. Chu, J. A. Finch

The formation of small bubbles in flotation is usually accomplished by the use of frothers, or sometimes is due to the presence of inorganic salts in the process water. The effective mechanism associated with the presence of these solutes is generally considered to be coalescence inhibition. However, recent work has demonstrated that the presence of frothers and salts also reduces the size of bubble at the initial formation stage. In this paper we adapt the same experimental setup to investigate the time that it takes for a bubble to form; for a known system power input, the energy to form a bubble can then be estimated from the time. The hypothesis is that the presence of frother and salt will reduce the time for a bubble to form, which can be interpreted as an added energy component being derived from the solute. Testing different types and concentrations of frothers and salts, the hypothesis is supported: the mechanical energy required to form a bubble decreases by about 10% in the presence of these solutes.

Jan 1, 2015

By J. Zinck

The management of mine wastes generated by both active and inactive mining is an ever more challenging issue. The cost to manage and treat mine wastes, including tailings, waste rock, treatment sludge and slag, is estimated at over $50B in Canada and the United States alone. Cost-effective technologies are required to meet both short and long term challenges and increasing environmental standards. This paper will provide an overview of novel and conventional technologies to manage mine waste particularly in the areas of waste stabilization, treatment and disposal technologies.

Jan 1, 2004