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By F. J. Macias, A. Bruland, F. E. Dahl

"Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples. INTRODUCTIONHigh investments are involved in the tunnelling industry, especially in Tunnel Boring Machines (TBMs) projects. Performance predictions and cost estimations are crucial for planning and risk management of TBM projects. Cutter consumption has a large influence in terms of time and cost, and an even greater effect in case of hard rock projects. Many factors are influencing the amount of cutters consumed in hard rock TBMs. Normal TBM operation results mainly in abrasive wear on the cutters and appropriate methods for abrasivity assessment are needed. Rock abrasiveness cannot be considered as an intrinsic property and the complete tribological system should be considered in addition to the geological properties of the rock.In the present paper, a new test method for abrasivity assessment in tunnel boring called Rolling Indentation Abrasion Test (RIAT) is presented. The traditionally used test methods for determination of rock abrasiveness uses sliding or impact contact in order to cause wear while the RIAT introduces rolling contact on intact rock samples. The ambition of the new test device is to have a reliable method to evaluate the cutter wear in hard rock tunnel boring by reproducing wear behaviour on rolling disc cutters in a more realistic way. It has been established by many authors that the abrasion of a cutter ring is proportional to its rolling distance (Rostami, 1997; Bruland, 1998). In the present work, the weight loss of a mini-cutter ring is measured subsequent to testing in order to evaluate wear in the rolling process and could hence be related to cutter ring wear. Indentation of the tools in the intact rock sample is considered as an indication of the surface hardness of the rock or the resistance to indentation by rolling."

Jan 1, 2015

By M. Scobie, T. Atkinson

"This paper reviews the development of new designs in extensible and high angle conveyor systems. These aim to overcome the limitations of prior alternative concepts in design. The application of such systems in strip, terrace, open pit and mountain mining is reviewed. IntroductionTruck haulage costs have tended to escalate in recent years. This has been primarily due to operations generally moving to greater depths with associated increases in haul distances . Periods of high inflation rates have also been experienced for diesel fuel oil, tires and other petroleum based products. Recent international political events have tended to regenerate concerns over future oil supply and price stability. For such reasons, conveyor based transport is becoming increasingly attractive. Truck haulage maintains an inherent flexibility and improvements continue to be made in performance and capacity. Doubts must exist, however, over the extent to which further economies of scale may be made. Conversely, belt conveyor systems do not suffer this constraint and have the following advantages:• Electrical power is used and the specific energy consumption is at least half that required for truck haulage.• Operating costs and skilled labour requirements are lower.• Equipment has superior longevity and is ""inflation proof"" .• Access roads can be steeper and narrower in most mine environments, reducing construction and maintenance costs.• They are less prone to breakdown and bad weather delays .• In long haul, high capacity operations conveyors can save substantially on capital cost.• Environmental impact is improved with reduced noise level, dust and atmospheric pollution. Although conveyor systems are less flexible in operation than truck haulage and although a breakdown in any part of the system can immobilize the total system, mechanical availabilities of + 80% are constantly reported by large operators. There would appear in the past to have been some prejudice against conveyor systems in hard rock mines due to lack of experience. Apparent reservations would apply equally 10 underground coal mines, yet practically all of these mines (and some underground hard rock mines) find conveyor systems more economical than other transport systems."

Jan 1, 1991

By L. Kong, V. G. Papangelakis, L. Li

"The Eh-pH diagram of lithium-titanium-water system at 25°C, 100 °C and 200 °C was constructed. It shows that there exist thermodynamic stability areas of Li2TiO3. This indicates a thermodynamic possibility for the formation of Li2TiO3 in aqueous solution. A hydrothermal process has been applied for the preparation of Li2TiO3 using TiCl4 and LiOH•H2O as raw materials. The prepared samples were examined with X-ray diffraction, scanning electron microscopy and thermo-gravimetric analysis and differential scanning calorimetry. The results show that temperature and washing condition have significant effects on the phase composition of the product. Phase-pure Li2TiO3 powders were obtained at 200°C with Li:Ti molar ratio of 2.0.INTRODUCTIONLithium-containing ceramics enriched in 6Li, such as Li2O, LiAlO2, Li4SiO4, Li2ZrO3 and Li2TiO3, are considered as tritium breeding materials (Saito et al., 1998; Roux et al., 1998; Johnson et al., 1998; Hoshino et al., 2002). In view of its admirable properties: low-activation, good thermal stability and thermal conductivity, excellent tritium release performance and reasonable lithium atom density (Kopasz et al., 1994; Roux et al., 1996; Saito et al., 1998; Wu et al., 2008), Li2TiO3 is recognized as one of the most promising candidates of tritium breeding materials. Meanwhile, Li2TiO3, as the precursor of H2TiO3-type lithium absorbent, receives more attention as the development of extracting lithium from salt lakes (Zhong, 2004; Zhang, 2010).Several synthetic techniques have been applied to prepare Li2TiO3 powders, such as solid-state methods (Lulewicz and Roux, 2002; Ramaraghavulu et al., 2011; Mandal et al., 2012), sol-gel processes (Deptula et al., 2002; Lee, 2008) and solution combustion routes (Cruz et al., 2006; Jung et al., 2006; Sinha et al., 2010). A solid-state method may produce a series of problems, including impurity contamination and difficulty in morphology control of the obtained powders, although the process involved is simple. The solgel process is prolonged and usually demands for multi-step reactions, while solution combustion route requires plenty of energy and easily causes product contamination by the fuel used. Owing to its environmentally benign and highly suitable characteristics in fabricating materials, hydrothermal technology has been widely used and became a powerful tool in the field of material synthesis (Yoshimura and Byrappa, 2008). For example, ZnO in the form of bulk single crystals, fine particles and thin films, which is an attractive photoelectric material, was successfully synthesized by hydrothermal process (Sekiguchi et al., 2000; Ohshima et al., 2004). A hydrothermal technique was also used to the preparation of carbon nanotube, which possesses outstanding mechanical, structural and electric properties (Bernholc et al., 1997), and is superior to the commonly used method (Gogotsi and Libera, 2000). There, it provides an option for preparing Li2TiO3. Laumann et al. (Laumann et al., 2010) synthesized cubic a-Li2TiO3 by hydrothermal reaction at 180 °C for 18 h, using TiO2 powder, comprising of anatase and rutile, and lithium hydroxide in de-ionized water. However, the prepared a-Li2TiO3 is extremely unstable with a maximum lithium loss of 75% when treated in bathing experiment."

Jan 1, 2012

By I. S. Laitinen

Outokumpu Technology has recently introduced new technology in both copper electrorefining and electrowinning. This technology includes, among other things, a new permanent cathode (Outokumpu Permanent Cathode) and new busbar technology (Outokumpu Double Contact System). The new technology has already been tested in commercial scale cells. To get a better understanding of the busbar system a multiphysical simulation model of the electrowinning and electrorefining cells was developed. A mathematical model of electrical conduction and heat transfer in a copper electrolysis cell was developed from partial differential equations. The model was expanded to a cell group including seven electrolysis cells connected electrically in series. The model was solved numerically using the finite element method (FEM). Using the model, different intercell busbar systems were simulated. Typical electrical disturbances, like loose contacts between cathodes and the main busbar and short circuits between electrodes, were included in the simulation. The results of the simulation runs with conclusions are presented in this paper.

Jan 1, 2007

By René G. del Villar, Jules Thibault, René del Villar

"Some key control variables of industrial processes, associated with product quality, often cannot be measured directly or frequently enough to establish adequate control. In such cases, it is possible to use available measurements to provide a prediction for these process variables and use them in a control strategy, thereby giving rise to what is now commonly called a softsensor.In some industrial grinding circuits, the on-line particle size analyzer is shared between various sampling points. Therefore, for a given location, the actual measurement is only available every 10 to 20 minutes, a delay which is unacceptable for automatic control purposes. To alleviate this problem, a softsensor based on an artificial neural network has been investigated. First, the structure of the neural network and different schemes for the training process are analyzed. Then, the performance of the neural network softsensor is compared with other inferential methods such as ARMA models and Kalman filters.IntroductionGRAHM, French acronym of the Research Group on Computer Applications in the Mineral Industry at Laval University, began in 1990 a research project on Knowledge Based Automatic Control (KBAC). This project, sponsored by a consortium of eight mining companies and the federal and provincial governments, seeked to screen advanced (knowledge-based) methods for data processing (filtering, mass balancing, etc) and automatic control (model-based) for their use in the mineral processing operations and the transfer of the project results to the sponsor companies.In parallel to more academic research work, a number of case-studies have been undertaken with the cooperation of partner companies. Among such works, a very successful one has been the design and installation of a new control strategy for one of the Kidd Creek (Falconbridge Ltd.) grinding circuits. This project was related to the evaluation of a number of control strategies and the implementation of one of them, as selected by the plant management, in the concentrator.A total of sixteen control schemes were evaluated on one of the dynamic phenomenological simulators developed at GRAHM, a trademark of this research group [ l]. The calibration of the simulator models was done based on industrial data gathered by GRAHM and Kidd Creek personnel. Then, the simulator was used to test the performance of various PID-based control schemes, designed to achieve the control objectives set by the Kidd Creek personnel. The best scheme proposed called for controlling the cyclone overflow particle size by manipulating the water addition rate to the cyclone feed box and the circulating load by manipulating the circuit ore feed. The particle size analyzer (PSI-200) available for monitoring the product size, was unfortunately shared (multiplexed) among various streams of the plant, which meant a 14 min delay between two consecutive readings for any particular stream. This induced the plant personnel to choose an alternative control strategy, one which controlled the cyclone feed density instead of the cyclone overflow particle size."

Jan 1, 1996

By L. Nutter, J. Clancy

"Barite is used extensively by the oil and gas well-drilling industry as a weighting agent. It is particularly well suited for drilling mud because of its qualities; it is non-abrasive, heavy, virtually inert chemically, easy to handle and inexpensive compared to other available heavy materials. Increased deep well drilling in Western Canada, and especially in the Arctic regions, could dramatically affect the demand for barite through this decade. Known deposits in northeast British Columbia are possible sources of incremental barite supplies, should the situation develop.IntroductionThe purpose of this report is to examine the opportunities for expanding barite production in British Columbia. Of primary interest will be the relationship between the projected future levels of production and consumption of barite in Western Canada and the extent to which increased domestic production could replace the need for imports in filling any expected supply shortages.After a brief overview of the nature and uses of barite and some of the relevant features of the barite supply industry, the discussion will turn to the supply gap in the Canadian market and the possibilities for import substitution.OverviewBarite is an industrial mineral which is used in large quantities by the oil and gas well-drilling industry. It is often an important component of drilling mud, a fluid circulated continuously in the well during the drilling process to lubricate and cool the drilling apparatus and to contain the high oil and gas pressures found at depth. Barite (BaSO4) is particularly well suited as a weighting agent for drilling mud because it is a heavy (specific gravity to 4.5) inert mineral which is inexpensive in relation to other materials having a high specific gravity. In the on-site use of drilling mud, ground barite is combined with numerous other solid ingredients and chemicals in the form of a slurry. Other advantages of barite include cleanliness, ease in handling and its non-abrasive character (hardness of 3-3.5)."

Jan 1, 1982

By CIM Standing Committee

The CIM Definition Standards on Mineral Resources and Reserves (CIM Definition Standards) establish definitions and guidance on the definitions for Mineral Resources, Mineral Reserves, and mining studies used in Canada. The Mineral Resource, Mineral Reserve, and mining study definitions are incorporated, by reference, into National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101). The CIM Definition Standards can be viewed at mrmr.cim.org. Readers should be aware that reports written by persons issuing technical reports that disclose information about exploration or other mining properties to the public in Canada are governed by a number of securities regulations.

May 10, 2014

"These standards were developed by the CIM for use with the value or worth of a Mineral Property as opposed to “evaluation” where the key objective is an economic assessment or determination of the economic merit of a propertyP1 .0 BACKGROUNDPl.1 There are at present no comprehensive standards for valuation of Mineral Properties in the Canadian mining industry. The Mining Standards Task Force (MSTF) of the Toronto Stock Exchange and the Ontario Securities Commission in its Final Report (January 1999) specifically recommended that the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) form a committee of valuation practitioners to review and advise on approaches to valuation of Mineral Properties.Pl.2 On May 5, 1999 at the Calgary Annual General Meeting, CIM Council approved the formation of a Special Committee on Valuation of Mineral Properties (CIMV al) to be co-chaired by Keith Spence (Chairman of the CIM Mineral Economics Society) and Dr. William Roscoe (Roscoe Postle Associates Inc.).Pl.3 The mandate of CIMVal is to recommend Standards and Guidelines for Valuation of Mineral Properties to be used by the mining industry in general and to be adopted by Canadian securities regulators and Canadian stock exchanges.Pl.4 The members of CIMVal represent of a mix of professional disciplines and experience in the field of Mineral Property valuation:Keith N. Spence (Co-chair), Alliance Pacific Resources Inc., TorontoWilliam E. Roscoe (Co-chair), Roscoe Postle Associates Inc., TorontoMichael J. Bourassa (Secretary), Aird & Berlis LLP, TorontoChristopher R. Lattanzi, Micon International Limited, TorontoRoss D. Lawrence, Watts, Griffis and McOuat Limited, TorontoPaul E. Lunney, Noranda Inc., TorontoCraig A. Roberts, Pacific International Securities, VancouverDavid A. Scott, CIBC World Markets, TorontoIan S. Thompson, Derry, Michener, Booth & Wahl Consultants Ltd., VancouverWilloughby A. Trythall, retired Placer Dome executive and consultant, Vancouver"

Jan 1, 2003

By Y. Vermeulen, J. Simoes, P. Guillo, A. Di Donate

New design techniques have been developed to optimize continuous casting (CC) refractory components. The overall objective is to increase CC productivity as well as steel quality by using optimized refractory from tundish-to-mold. These techniques allow the prediction of steel and refractory chemical interactions and, thus, steel chemistry evolution as well as build up and corrosion occurrence. Specific fluido-dynamic models (CFD) have also been developed to better take into account the physical parameters at the steel/refractory interface and to optimize steel flow control. The CFD model can be coupled with refractory chemical interactions to simulate steel chemical evolution. These two different approaches result in shape and material modifications. They are completed by dedicated thermal stress analysis in order to improve thermal shock resistance. The mechanical FEA evaluations take into account specific mechanical behavior of refractory components as well as high temperature evolution of their properties.

Jan 1, 2004

By M. Knot

Fans delivered to the Russian Federation, and eventually to countries of the former U.S.S.R., for mine ventilation must meet the legislative requirements of local jurisdictions. This paper presents a discussion of these legislative requirements and presents examples of fan equipment designed to meet the requirements. The legislative obligations discussed include four (4) separate requirements, including: ?Technical design requirements ? The Federal Agency for Technical Regulation and Metrology is responsible to issue a GOST R certification declaring conformance to the requirements ?Operational requirements ? A ?License for Application? must be obtained prior to operation ?Explosion risk requirements ? If the area of operation includes potential for explosion a special certificate must be obtained ?Technical condition requirements ? Market segments within the mining industry require special conditions that must be satisfied Examples of fans designed specifically for use in the Russian Federation are also discussed and examples provided. Designs for fan volume flow control will be highlighted.

Aug 1, 2013

By J. J. Jonas, G. R. Stewart, N. Pokutylowicz, S. Yue, R. Varano, A. Elwazri

Differing thermal histories in and around a weld can lead to differences in grain size, phase composition and morphology of precipitates; mechanical properties will vary accordingly. Hardness testing gives limited information and the machining and testing of tensile and/or impact specimens that would reveal these variations (which may occur over very small distances) is not practical. Therefore, in this investigation, shear punch testing was applied to measure the variation in the room temperature mechanical properties of a welded pipeline steel.

Jan 1, 2005

By Greg Collins

BUCKO EXPLORATION HISTORY ??1964-Discovery ??1970?s -114 holes totaling 34,000 metres drilled -vertical shaft excavated to a depth of 300 metres (1000 Level) plus 800 metres of underground development -Exploration program cancelled due to Falconbridge economic issues ??1990?S-19 holes drilled totaling 9,600 metres ??2000 -13 hole 4,600 metre exploration program by Nuinsco Res.

May 1, 2006

By R. R. Rogers

ABSTRACT The experiments described demonstrate that crude commercial lithium containing in the order of 0.5 per cent sodium can be refined, the resulting metal containing as low as 0.001 per cent sodium. During the process, the metal is vaporized and condensed at a gauge pressure of less than 0.04 micron. Considerable operating data and a detailed description of the experimental equipment are included. INTRODUCTION DUE TO THE unusual properties of lithium metal, its use is likely to increase considerably during the next few years (1, 2). This is of particular interest to Canadians because there are important deposits of lithium-containing minerals, especially spodumene, in Canada and it is hoped that lithium compounds and lithium metal will be produced from these deposits in the fairly near future. In order to assist in the development of this industry, the Mines Branch of the Department of Mines and Technical Surveys has initiated a programme of research in lithium metallurgy. In 1948, a paper (4) was published on methods of producing lithium metal and its alloys. Data on the corrosion resistance of some lithium alloys were included. In 1949, a paper (3) was published which showed that the addition of a small percentage of lithium to zinc anodes used for cathodic protection will improve their usefulness under certain circumstances.

Jan 1, 1951

By T. Xue, A. Singhal, D. Wrana, I. Mihaylov

"At Vale's Thompson Nickel Refinery, the copper and arsenic in the nickel electrolyte are removed by precipitation using H2S, generating a sulphide precipitate containing about 40% Cu, 8% Ni, 2 to 4% As and 30% S. This residue has been typically stored in impoundment ponds within the plant site. Various options for reprocessing it have been investigated over the years. One of the options involved oxidative pressure acid leach, whereby over 95% Cu, Ni and As were extracted. More recently, an atmospheric alkaline sulphide leaching process for selective removal of 70 to 90% As was developed and mini-plant tested. After alkaline sulphide leaching, the dissolved arsenic is precipitated as stable basic ferric arsenate (BFA) with the addition of ferric sulfate, while the low-arsenic Cu/Ni sulfide is suitable for processing in Vale's operations elsewhere in Canada.INTRODUCTIONVale’s Thompson Nickel Refinery was commissioned in 1961 and currently it has the capacity to produce about 56,700 tonnes per year of electrolytic nickel as cathode slab and rounds products. A sulphate and chloride mixed electrolyte is used in the Thompson refining process and it typically contains 75 to 85 g/L Ni, 50 to 60 g/L Cl, 90 to 120 g/L SO4 2-, 25 to 30 g/L Na and 8 to 9 g/L boric acid. The main impurities in the Thompson anolyte are copper, cobalt, arsenic, iron and lead.The simplified Thompson electrolyte purification flowsheet is shown in Figure 1 (Oliver & Wrana, 2009, Goble & Chapman, 1986); it consists of precipitation of copper, arsenic and lead with H2S, followed by nickel replenishment with ground matte and acid and removal of cobalt and iron with Cl2 and NiCO3."

Jan 1, 2012

By V. Polotski

This paper describes a platform for autonomous operations in open pit mining environments. A typical operation consists of: (1) Initial locomotion toward a remote worksite; (2) Pattern navigation within the worksite; (3) Worksite manipulations and (4) Return locomotion to the start location. The platform includes precise localization module based upon the fusion of odometry, inertial and GPS measurements. The guidance module starts from a set of way points specified on a GPSreferenced map and plans and executes the mission. A typical mission includes specified manipulative tasks along the navigation path. During motion execution the on-board system continuously verifies that the path is free of obstacles and that the hardware is not overloaded. Momentary losses of external positioning measurements does not adversely affect the performance, owing to the redundancy in position and heading estimation. A rehearsal phase follows planning and allows the supervisor to examine the kinematic behavior of the platform during motion, thus reducing the need for continuous monitoring during execution and providing protection against potential losses of communication.

May 1, 2003

By A. C. Halferdahl

The Granby ores may be divided into three groups or classes. The No. I ore is a heavy pyrite, chalcopyrite, pyrrhotite, sulphide carrying some free silica, and calcite. No. 2 ore carries the same general group of sulphides as does No. 1, but in a lesser amount. The gangue is an altered greenstone. No. 3 ore has a smaller amount of sulphides than either of the others. Analyses of these ores is as follows: Cu. Si02 Fe. CaO S. Al 203 MgO No. I. Per Cent. 1.8 17.5 33.0 5.7 34.5 2.3 1.3 No. 2 Per cent. 2. 0 35. 6 23. 9 4. 3 I .5. 0 9. 2 6 .. 0 No. 3, Per cent. 1 . 5 40. 9 21 . 7 3. 0 I 1 . 3 11 . 0 5 . 4 The sulphide minerals in No. 2 and No. 3 ores occur largely in bands in the gangue, and for these portions comparatively coarse grinding serves to release the gangue. Drill cores show a certain dissemination of sulphides in portions of the rock, so that grinding to 5 per cent. + 65 mesh with 65 per cent.-200 mesh liberates the sulphide minerals very completely. The association of the sulphides is fundamental. The pyrite was probably deposited first and was followed by a portion of the chalcopyrite, or these two portions of the sulphide minerals were deposited together.

Jan 1, 1924

By H. Ishimoto

It always has been a serious issue to improve safety in mine sites, demolition work sites, and civil engineering work sites. Especially, collision accidents caused by construction equipment damage not only the productivity of operations but also the health and life of workers in those work sites. To solve this problem, a variety of worker auto-detection means are developed so far, but they have not still become widely used in actual worksites. There have been two controversial points in the prior methods. One is that they were not enough in respect of the detection accuracy and certainty, and the other one is that the information of the detection results was not comprehensible to the operator of equipment. In this paper, the functional requirements of the obstacle detection system in earth moving work site is redefined at first, and then, it is proposed to apply a stereo vision to the obstacle detection system for an excavator. The system consists of horizontally arrayed two digital cameras with low distortion lens, an image processing controller, and a monitor for an operator in the cab. Stereo vision calculates the depth image from images of two cameras and detects the presence of obstacles, its distance, direction, and dimensions. Sensed obstacles are informed to the operator in the monitor image. Preliminary experiments are conducted with a stereo vision system mounted on a real equipment in a demonstration site. The result shows that two controversial points of the conventional technologies are improved, and that the applicability of this system is validated.

Aug 1, 2013

By B. K. Gorain

Barrick' s Buzwagi copper-gold deposit in Tanzania comprises oxide, saprock and sulphide mineralized zones averaging approximately 0.058oz/t gold, 0.13% total copper and 0.03% cyanide-soluble copper. A comparative evaluation of the project based on two potential flowsheet alternatives is presented. The first flowsheet included a gravityconcentration and carbon-in-leach (CIL) plant. The second flowsheet was based on a Gravity-Flotation-CIL plant, which proved to be more economically robust. Selective flotation of copper minerals to produce a saleable copper concentrate proved to be challenging. Detailed characterization of the Buzwagi deposit was carried out through understanding of ore mineralogy, mineral liberation, floatability and selectivity, reagent chemistry and regrinding issues. With this insight, a flotation concentrate of greater than 25% Cu was achieved, recovering a significant amount of copper minerals and tellurides. The overall economics of the project improved significantly with the addition of flotation. Leach tests on gravity and flotation tailings showed an overall increase in gold recovery of approximately 6% for a Gravity-Flotation-CIL plant compared to that for a Gravity-CIL plant.

Jan 1, 2007

By S. A. Sadough vanini

In this paper the influence of temperature on the flow behavior and rheological characteristics of an A356 alloy in the semi-solid state using backward extrusion process are studied experimentally and numerically. Simulation process is done by dynamic explicit in ABAQUS software for each forming condition. A cooling slope treatment was employed in order to obtain a non-dendritic microstructure. Experiments were performed in 5 temperatures and 4 different wall thicknesses. In the low forming speeds, liquid fraction had time to escape from solid phase forward the samples? wall. This condition was the main reason for the segregation phenomenon seen in the base and walls. Viscosities were determined using the force-displacement graphs obtained form back-extrusion tests. As observed experimentally, in a constant temperature, increase of shear rate resulted in decrease of alloy viscosity exponentially. Raising the temperature increases the liquid fraction hence reduces the semi-solid alloy viscosity. The results of experimental and simulation are compared and there is a good adaptation.

Oct 1, 2011

By M. P. Brameld, G. Archambault, R. H. McCorkell

"The rates. J. at which materials emit radon are of interest in studies of the sources of radon in mines. buildings. soils overburden and other places where it may indicate the location of ore or be a health hazard. Here J values were determined by measuring the radon concentrations by means of scintillation counters or alpha-particle track detectors in chambers in which specimens were sealed. Errors in the measurements due to leakage from the chambers. lack of secular equilibrium in the decay series of the radon measured, or the limited rate of diffusion of radon from powders or within the chambers were shown to be insignificant or could be corrected. Scintillation counter measurements are highly reproducible; track detector measurements also appear useable and may be made on many small samples using small, simple chambers. J measurements were made for uranium ores, drill cores, standard CANMET pulps. concrete and gypsum board. Powdering of ores had little effect on their J values.IntroductionIn the mining and mineral sciences, radon (222Rn) is of interest chiefly for two reasons: in geochemical exploration for mineral deposits its presence in soil. overburden and water in more than background concentrations may indicate the existence and locations of uranium deposits and, if present in sufficient concentrations, it is a possible health hazard in mines, mills and other places where people live and work. The latter aspect of radon's role has received considerable attention recently(1,2,3,4,5), and surveys of soil-gas radon concentrations have been used for some time in searches for uranium deposits(6,7,8,9,)."

Jan 1, 1981