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By Jose R. Hernandez-Aguilar, Jeet Basi

"The study evaluated the impact on overall circuit metallurgy of improving the performance of the two flotation columns that make up the final Mo cleaning stage in the Cu/Mo separation circuit at Highland Valley Copper mine. The results showed that a key factor to improve the overall circuit metallurgy was to control the size of the bubbles generated in the columns. When a large proportion of small (< 1 mm) bubbles were generated, the production rate of solids-in-concentrate increased by a factor of 4-5 compared to typical production figures without compromising concentrate quality. This increase in concentrate production rate reduced the circulating load in the circuit causing a significant increase of Mo recovery. A statistical analysis of historical production data showed a strong relationship between final concentrate production rate and overall Mo recovery. This relationship along with the results from this study indicated an opportunity to increase the recovery of Mo from 90% (typical) to 94% without downgrading concentrate grade. This 4% increase represents about 14,000 lbs or $500,000 worth of Mo each month at current metal prices.To provide a rational interpretation of the results, this study also examined whether the model of Gorain et al. (1997; 1998; 1999) could explain the increase of Mo recovery seemingly resulting from the decrease of bubble size. The data showed that the model predictions did not agree with the experimental data, i.e., for a given change (decrease) of bubble size, the predictions underestimated significantly the observed recovery increase. An interpretation based on the fundamental analysis of Finch and Dobby (1990) and Hernandez-Aguilar et al. (2005) is proposed to explain the discrepancy between measurements and predictions obtained from Gorain et al.’s model.INTRODUCTIONIt is generally accepted that the size of the bubbles generated in a flotation cell – a concept usually referred to as “bubble size” – has a significant effect on metallurgical performance. However, a significant number of mineral processing practitioners often question, with valid reasons, the practical benefits of implementing process improvement strategies based on controlling bubble size. “Small” bubbles are often considered to be “favourable”, but how small they need to be for a particular case, or how to adjust operating conditions to control a target bubble size, or whether the bubbles need to be smaller in the first place are questions that usually remain unanswered. Two reasons explain this situation."

Jan 1, 2009

By A. A. de Gast, R. B. James

"The metal content of ore blocks can be calculated by the use of many different methods. These methods range in sophistication from manual calculation to computer. oriented techniques. In this case a cubic polynomial regression model is developed to depict the grade distribution of an orebody. Mine production, in stope dimensions, is then simulated on a computer to predict the output of metal content. The volume, grade and variance of the grade are estimated by triple integration and matrix algebra. A case study shows reasonable agreement between the results from the mathematical model and the mine geologists' estimate of production and ore reserve grade and tonnage."

Jan 1, 1972

By W. Hawker, A. M. Ivana

"Pressure oxidation is used to liberate gold from refractory sulphide ore and concentrates with over fifteen autoclaves in operation. Despite the importance of pressure oxidation, the autoclave chemistry and chemical thermodynamics are not well established. For example, there is no consensus on aqueous iron speciation or stability of jarosite phases. Additionally, there remains questions about basic ferric sulphate formation and stability. In addition to a review of the current state of knowledge, a methodology to study the ferric precipitation reaction and relate the results to chemical thermodynamic predictions is presented which will be used to accurately define the phase boundaries of the iron precipitates in the future (hematite, jarosite and basic ferric sulphate).INTRODUCTION With declining availability of orebodies that respond to simple leaching conditions, pressure oxidation has become a prevalent technology to liberate gold locked in sulphide mineral matrices. Gold pressure oxidation was established 32 years ago, with McLaughlin being the first facility in 1985 (Thomas & Pearson, 2016). Pressure oxidation is carried out at elevated temperatures ranging from 180 to 240°C as shown in the summary of operations in Table 1 (Ruonala et al., 2016; Fleming, 2010).A considerable amount of research has been done to study iron solubility and precipitation under autoclave conditions (Tozawa & Sasaki, 1986; Umetsu et al., 1977; Sasaki et al., 1993; Fleuriault, 2016; Cheng & Demopoulos, 2004; Papangelakis et al., 1994; Yue et al., 2003). These reports provide a description of the process chemistry and iron behaviour in the autoclave. However, there remain questions about the type and stability of aqueous species and solid phases. This detailed information is required to build a robust chemical thermodynamic model of the system, allowing for equilibrium and kinetic reaction limitations to be discerned."

Jan 1, 2017

By Alex Cormode, Carlos Perucca

"Sylvinite ore from the Saskatoon area typically contains about 5% insolubles, occurring as clays and carbonates. These insoluble slimes must be removed sufficiently well to permit an efficient subsequent potassium chloride flotation, due to their high adsorptive capacity for amines used as potash collectors. The insolubles are liberated from sylvinite by high attrition scrubbing in a slurry. The liberated slimes are separated by multistage cycloning or by a selective flocculation-flotation process.An outline of the potash processing operations at Agrium Vanscoy Potash Operations is given, emphasizing the insoluble slimes froth flotation separation process. This process was originally implemented at the Agrium plant in the mid- 1970's and replaced a hydrocyclone system.IntroductionAgrium Vanscoy Potash Operations is located 40 Km southwest of Saskatoon, almost midway between the communities of Vanscoy and Delisle. Processing operations started in 1969, and the annual production capability was subsequently increased to the current 1.8 MM tonnes per year of muriate of potash.The mining operation at Agrium Potash which was described in a paper by Jones and Pruggerl , is done underground using four large continuous double rotor boring machines for the main production with development done by heliminers. Annual ore production is 5.5 MM tonnedannum. Ore is hoisted 1,100 m to surface for processing."

Jan 1, 1999

By P. A. Mingione

"AEROPHINE@ 3418A is a unique sulfide mineral promoter produced by Cyanamid, based on phosphine (PH3) chemistry. It has proven effective as a collector for the sulfide minerals of copper and particularly lead (galena), as well as for secondary gold and silver values. AEROPHINE 3418A has widest application as a Cu and/or Pb collector for complex ores of Cu-Zn and Pb-Zn, which frequently have significant quantities of associated precious metal values. Advantages shown in the use of AEROPHINE 3418A are improved selectivities against Zn- and Fe-sulfides, increased precious metals recoveries, reduced total collector consumptions for Cu and/or Pb flotation, and increased flotation kinetics leading to higher recoveries of these values. Operating plant, pilot plant and laboratory test data from treating different ores are presented, demonstrating the advantages in use and preferred application of AEROPHINE 3418A.INTRODUCTIONCyanamid operates the only phosphine and phosphine derivatives plant in North America, located in Niagara Falls, Ontario. Specialty chemicals manufactured at this facility are used in many diverse applications, including solvent extraction reagents and textile flame retardants. A unique phosphine-based sulfide mineral promoter, AEROPHINE 3418A, is also produced. The origins of AEROPHINE 3418A promoter date back to the 1960's, when it was established that sulfide mineral collectors based on phosphine chemistry demonstrated efficacy. This new collector chemistry was found to provide flotation performance differing significantly from those of more traditional thiol collector chemistries such as xanthates, dithiophosphates, mercaptobenzothiazoles, thionocarbamates and those with xanthogen groups. Some of the advantages ultimately demonstrated by AEROPHINE 3418A promoter compared to these traditional collectors include:"

Jan 1, 1990

By Jarret Thomson

An understanding of groundwater flow is essential for many aspects of mining. This is especially true for the process of shaft sinking through the sandstones of the Manitou Falls Group in the Athabasca Basin of northern Saskatchewan. Experience has shown that the hydraulic conductivities of these sandstones can be relatively high, especially in zones containing natural fractures. To develop a better understanding of the inflow potential into a shaft, a laboratory testing program was undertaken to investigate the hydraulic conductivity of fracture core samples from the Manitou Falls Group. This program involved the measurement of hydraulic conductivities under steady-state flow conditions, while cycling the effective confining pressure across a span that is representative of in-situ conditions. The change in fracture aperture was simultaneously recorded at each confining stress level. It was found that existing relationships relating aperture and flow did not accurately capture the behavior of the samples tested. The effects of fracture staining and infilling were also investigated, and were found to have a notable impact on the hydraulic conductivity.

Jun 1, 2012

By John A. Herbst, Alexander Potapov, Xiangjun Qiu

"High Fidelity Simulation is a name applied to the use of first principles modeling tools including Discrete Element Modeling (DEM), Computational Fluid Dynamics (CFD) and Discrete Grain Breakage (DGB) to mathematically describe and study processing systems. Over the past few years, significant advances have been made in High Fidelity Simulation applications, particularly as many mineral processors have been drawn to the study and use of DEM of grinding mills for optimization purposes. This presentation provides an introduction to High Fidelity Simulation, with an emphasis on DEM. It will include insights into current applications of these tools including the optimal design (wear and throughput) of mill lining systems and media selection, the analysis and design (flow and efficiency) of the back-end of grate discharge mills. Advantages of full mill simulations versus individual sub-process simulations will be demonstrated for a SAG mill with different discharge system designs.INTRODUCTIONHigh Fidelity Simulation is providing mineral processors with the opportunity to analyze the behavior of mineral processing equipment from a fundamental or microscale point of view. In the past complex phenomena such as tumbling mill grinding had to be analyzed using black box tools such as residence time distributions for transport and classification functions for passage of particles through grates; while breakage had to be analyzed using PBM models who derived their form from theory but required direct measurement of kinetics. Today with the help of DEM, CFD and DGB these can be analyzed at a very fundamental level.The key element of DEM simulation is the application of Newton’s laws of motion to individual objects or discrete elements. Using this simulation method one can describe the position, velocity (both translational and rotational) of all objects and the transfer of momentum to other objects (Mishra and Rajamani, 1992; Cleary, 1998; Nordell et al, 2001)."

Jan 1, 2003

By Robert D. Brown

"The Conservative Government &apos;s budget proposals brought forward on December 11, 1979 have been withdrawn, but they are far from dead. On the contrary, a number of those budget proposals, especially the ones which would close loopholes and result in other technical changes being made to the Income Tax Act, should be considered to be alive and well.It is not unreasonable to expect the next government, of whatever political persuasion, to reintroduce many of these technical changes in the next federal budget. For that reason, last December&apos;s budget may have offered an interesting preview of what the mining industry and other taxpayers can expect in 1980. It is quite possible that some of these changes may be effective as of the original dates announced in the withdrawn budget proposals.This month, ""Tax Notes"" reviews the main pro visions of Mr. Crosbie&apos;s December, 1979 budget, with a primary focus on the changes that would have affected the resource sector.It must be emphasized that all of the budget proposals discussed herein have been withdrawn, that none of them are law and that any actual changes in our tax rules will have to be dealt with by the new Parliament that will be assembled following the February 18 election. December 1979budget withdrawnThe federal budget proposals brought forward by Finance Minister John Crosbie on December II, 1979 were withdrawn as a result of the defeat of the Conservative Government on a motion of non-confidence in the House of Commons on December 13. However, it appears quite possible that at least some of the proposals may be introduced into Parliament at a future date, possibly with retroactive effect.In a press release issued by the Department of Finance, Finance Minister John Crosbie stated that if the Conservative Government is returned to power, it will reintroduce all of the measures contained in his December II budget.Mr. Crosbie stated that all of the income tax measures contained in the budget would be reintroduced, effective on the dates indicated in the Notice of Ways and Means Motion tabled on December II. Some of the more important measures in December II budget, and their effective dates as indicated in the Notice of Ways and Means Motion, are discussed below.The December budget had also introduced or increased excise taxes or duties on gasoline, wines, cosmetics and photofinishing. If the Conservative party is re-elected, these measures will be reintroduced with prospective effect (i.e . effective as of new dates to be announced in the new budget)."

Jan 1, 1980

By F. M. Doyle, G. Sidhu, A. J. Dussault, A. Raygani

There is a growing demand for rare earth metals for use in high strength permanent magnets, most notably Nd2Fe14B. Rare earth metals are extremely reactive, with reduction potentials around -2.5V SHE, and are conventionally produced by molten salt electrolysis. The current work was done to investigate an earlier report of electrodeposition of a neodymium ferroalloy from aqueous solution, to determine whether this approach could be an environmentally and economically competitive commercial approach for producing feedstock for permanent magnets. Such a process would be analogous thermodynamically to the Castner- Kellner process, in which aqueous sodium chloride brine is electrolyzed in cells with mercury cathodes. Metallic sodium forms an alloy (amalgam) at the cathode, thereby lowering the activity of the metallic sodium significantly below unity and making the reduction potential of sodium significantly less negative than the standard reduction potential. Here we report the effects of Nd/Fe ratio in the electrolyte, current density, temperature and two different complexing agents, glycine and cysteine, on the composition and morphology of the electrodeposits, along with current efficiency. The energy needed to produce neodymium as Nd:Fe alloys by aqueous electrodeposition was compared with values estimated for production by molten salt electrolysis and the thermodynamic energy requirement.

Jan 1, 2014

By Changmiao Liu, Dong Dong

"Magnesite is a major mineral resource in China, whose output and export are massive and quite important to the world. Flotation performances of eight anionic collectors on magnesite were studied to find the proper ones. Micro-flotation results indicated that collectors of HOl, SDBS and AEP had outstanding flotation performances on magnesite, with the recovery ratio all reaching above 90% in a wide range of alkaline pulp. Solution chemistry calculation, Zeta potential and FTIR measurements were employed to reveal the interaction mechanism between anionic collectors and magnesite surfaces. Solution chemistry analysis indicated that the main active components of HOl, SDBS and AEP were anions and association complex anions in alkaline pulp. Magnesite surface was negatively charged in the alkaline pulp. The active sites on magnesite surface were mainly the components of MgOH-, Mg (OH)2, and MgCO3 when the pulp pH was over 8. Anionic components of HOl, SDBS and AEP reacted with Mg in magnesite surface to make the insoluble anionic salts. And the chemical adsorption was confirmed by the FTIR measurement evidences.INTRODUCTIONAs an important industrial mineral, magnesite has been widely applied in metallurgy, building materials, chemical industry, agro-pasturage and other fields (Hu et al., 2006). It is a major mineral resource in China with abundant reserves. Its output and export are massive and quite important to the world. Liaoning province is rich in magnesite, whose reserves and production both come first in China. So far the proven reserves have reached 2.91 billion tons, accounting for more than 90% of total reserves in China, and more than 25% in the world (Li et al., 2012).Magnesite ores in Liaoning province mainly contain crystalline magnesite, and the gangue minerals of quartz, dolomite, talc, tremolite, chlorite and carbonaceous materials. Some ores also contain a little pyrite, chalcopyrite, hematite and apatite. Most of the ores must be preprocessed to separate the useful parts from the large amount of gangue minerals, so that their value and industrial application can be enlarged and promoted.Flotation is commonly used to process the magnesite ores, and the conventional flotation methods include anionic and cationic flotation. In the former, gangue minerals of silicates were separated by using amine type cationic collectors. After the impurity minerals were removed, high qualified magnesite concentration could be gained. For the cationic flotation method, it had some drawbacks of lower recovery ratio and poor performance in the lower temperature pulp (Li et al., 1995)."

Jan 1, 2016

By K. E. Haque

"This paper is a brief overview of the role of oxygen in cyanide leaching of gold feeds (e.g. ore, concentrate). As the majority of gold occurs in the elemental state (Au °), its oxidation is of vital importance for dissolution in the cyanide lixiviant. The cyanidetion at high pH is favourable for the oxidation of Au° with a mild oxidant such as air or oxygen. Beside oxidation of gold, deleterious effects of soluble sulphides, arsenates, antimonates on cyanidation of gold can be alleviated by preaerating the leach slurry with air or oxygen (i.e. preaeration process).If gold is refractory due to its occlusion in sulphides, silicates, tellurides, etc. then gold liberation is possible by roasting in the presence of oxygen or by leaching under oxygen pressure. The data in the recent literature indicate that reactive oxygen supplied by H202, Na202, Ca02 or 03 during cyanidation can accelerate considerably gold oxidation-cyanidation and yield high gold recovery in much shorter leach time. The information compiled in this review leads to the conclusion that oxygen plays a vital role in the dissolution of gold in cyanide lixiviant."

Jan 1, 1992

By A. O. Dufresne

A Step which, it is believed, will prove extremely beneficial to the Quebec asbestos-mining industry was taken during 1931, when the asbestos mine operators of the Province assembled to work out a uniform method of naming the products of their mines. The outcome of several meetings was the drawing-up of a classification which defined, limited, and designated anew the numerous grades of asbestos marketed. It entailed no drastic departure from the existing processes of grading, nor any revolutionary changes in methods of testing, but aimed rather to perfect existing methods. The classification proposed has been accepted by all operators in the Province, who, from January first of this year, began introducing the new nomenclature. Unless one is conversant with the properties and mode of occurrence of chrysotile asbestos, with the unique milling methods devised for its recovery, and with the history of the development of their technique, he may not readily understand the basis of the new classification. For information on these and other data concerning the industry, the reader is referred to a recent publication, Chrysotile Asbestos in (Canada, by James Gordon Ross, issued by the Mines. Branch of the Department of Mines, Ottawa. The object of this paper is to present briefly some of the phases in the evolution of the classification of Canadian chrysotile asbestos, in the hope that the recent effort to standardize the marketable products of one of Canada&apos;s most important non-metallic mineral industries will open a field for discussion, fruitful in new ideas and constructive suggestions. The necessity for the grading of asbestos results fundamentally from the fact that the price per ton depends on the length of fibre. At all times in the history of the industry, the very limited available supply of the longer grades, as well as the requirements of the trade, have caused relatively very high prices to be paid for fibre over half an inch in length, while for the shorter grades the price decreases rapidly, and at a rate which bears no proportionate relation to the length of fibre.

Jan 1, 1932

By M. E. Holter

"Three main potash members are recognized within the Prairie Evaporite Formation of Saskatchewan and have been designated, in ascending order, the Esterhazy, Belle Plaine and Patience Lake members. Each is composed of sylvinite near the geographic center of the member and becomes increasingly carnallitic marginally. Each stratigraphically higher member has a narrower carnallitic margin. The sharp contact between carnallitic and non-carnallitic components of the formation describes a surface which may be traced regionally and is not related to bed-ding. The contact rises higher in the stratigraphic section toward margins of members. Within each of the three members, analyses indicate that carnallite becomes more abundant toward the north whereas sylvite and insolubles, increase toward the south. Within each member, areas rich in carnallite are coincident with areas in which the member as a whole is thicker than averag,e. The Belle Plaine Member contains the highest concentrations of carnallite, the Esterhazy the lowest. A maximum content of about 30 per cent sylvite is common to all three members. Insoluble contents increase in successively higher members.Map studies are combined to outline the economic potential of the potash beds in terms of depth to the top of the Prairie Evaporite, ""salt-back"" thicknesses and sylvite grades for each member."

Jan 1, 1971

By Gary Raymond

The Similkameen Division of Newmont Mines Limited operates a low-grade open-pit copper mine in southern British Columbia. The copper mineralization is extremely erratic.As a result, over seven years of operation, ore control methods have evolved from standard flagging based on blast-hole assays, through an in-pit grab sampling system, to the present method of mining to computer-determined ore-waste boundaries based on geostatistics. These improved ore control methods have resulted in a gain of at least 25% on ore tonnage miffed, at the same grade as obtained using earlier techniques. At the same time, geostatistical ore reserve estimates are now within 7% of milled ore tonnage and grade on a yearly basis, whereas the original polygon ore reserves under-estimated mineable ore tonnage by 15% to 45% and over-estimated grade by about 20%. The author discusses why traditional ore estimation methods give poor results in erratically mineralized orebodies and describes the geostatistical approach to the problem.

Jan 1, 1979

By M. Kosugi, Y. Kon, M. Kawata, J. V. Satur, K. Mitsuhashi, C. Tokoro, K. Horiuchi, R. Kawarabuki, B. Calabia

"Liberation of copper minerals is important in ensuring high flotation efficiency in copper sulfide flotation. The high pressure grinding roll (HPGR), microwave (MW), and electric disintegration (ED) are known to feature enhanced liberation over conventional comminution machines such as jaw crushers and ball mills by producing internal stresses on minerals or mineral grain boundaries through high compressive forces, thermal expansion of minerals, and pulsed high voltage discharges, respectively. In this study, each of these methods was applied before ball mill grinding to investigate its effect on enhancing the liberation of copper minerals in a low grade and fine-grained copper ore. The copper minerals observed in the tested ore sample are bornite, chalcocite, and chalcopyrite, and their grain sizes range from 10 to over 100 µm. Calcite, quartz, and feldsparare confirmed as gangue minerals. The liberation of the copper minerals by the different methods was analyzed using the mineral liberation analyzer (MLA) and compared. The result showed that the HPGR crushing was the most effective for enhancing copper mineral liberation. HPGR bench-scale test was then conducted on the copper ore and flotation was applied on a HPGR-treated sample to confirm the improvement in the flotation performance by applying HPGR.INTRODUCTIONIn order to recover copper minerals by flotation, copper ore is usually ground by ball milling to liberate the copper minerals from gangue minerals. In the case that the fine size copper minerals are targeted, grinding of the copper ore to a finer size is necessary to increase the copper recovery. However, finer size grinding by ball mill increases energy consumption significantly, which might deteriorate the economies of the mineral processing operation. HPGR, MW, and ED have been recently the focus of researchers as new techniques for enhancing the mineral liberation in mineral processing (Tavares, 2004; Kingman, 1998; Wang, 2010).HPGR crushing is considered to generate micro cracks along mineral boundary when rocks pass between two rolls by applying high compressive force. In the MW treatment, micro cracks are reported to be generated at crystal boundaries by differential thermal expansion of crystals attached to each other. In the ED treatment, micro cracks are known to be produced by plasma current flowing along mineral grain boundaries. These treatments are expected to increase mineral liberation (Fujita, 2001),improve flotation performance(Michaelis, 2005), and reduce ball mill work index(Kaya, 2010)."

Jan 1, 2017

By Sadough vanini Ali

Charpy impact energy of functionally graded steels produced by electroslag remelting in crack divider configuration has been modeled in various strain rates. It has been well known that majority of materials indicate different behaviors under different strain rates and temperatures. Therefore, modifying the elastic-plastic model considering the effects of strain rates and temperature gives us an acceptable prediction of these composites behaviors in impact test. In this investigation, graded steel was divided in to several layers in which the layers have the same strains under the impact. Constitutive equation describing the flow stress variations as a function of strain rates and temperatures, have been used to express the stressstrain behavior of layers. The parameter values of constitutive equation determined for all the layers via using the boundary conditions based on composite graded behaviors which were the characterized ferrite, austenite, bainite and martensitte phases. Consequently by applying the rule of phase mixtures and ascribing the impact energy of each layer to the area of stress-strain curve of the same layer, the whole impact energy of composite is the sum of layers impact energy with considering the layers volume fraction.

Oct 1, 2011

"RÉSUMÉOn discute les principales sources de dilution au cours d’une exploitation souterraine. Les différentes définitions de la dilution en usage sont analysées. Une nouvelle méthodologie de calcul simplifiée et facile à utiliser dans la pratique minière est présentée. Cette méthodologie permet de remplacer les différentes expressions analytiques en usage par les deux facteurs de dilution seulement : un «facteur de dilution planifiée» lié à la sélectivité d’abattage au niveau de la planification minière et un «facteur de dilution additionnelle » permettant de juger de l’efficacité du contrôle de terrain et de la dilution pendant l’exploitation souterraine. L’application de cette méthodologie donnerait un outil nécessaire aux niveaux de la planification, du suivi des travaux d’exploitation et d’éventuelles études comparatives des coûts entre les différentes situations minières.ABSTRACTThe principal sources of dilution during underground evaluation and mining are discussed, then definitions of ore dilution currently in use are analyzed. These definitions vary depending on the authors. A new ore dilution evaluation methodology is proposed, replacing the ten different analytical expressions by only two: the planned dilution factor related to the stoping selectivity, done at the mine planning level, and the additional dilution factor related to the efficiency of the dilution control measures during stoping operations. The conclusion shows that the use of this methodology would be a definitive asset in planning, in stoping operations follow-up, and in future costs comparison studies between mining operations."

Jan 1, 2001

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&apos;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

By Ray Mason

Marathon PGM Corporation?s PGM-Cu Project in Northwestern Ontario (Figure 1.0) serves as a case study to describe the process involved in advancing a deposit from grass roots exploration to the completion of several feasibility studies and the parallel commencement of environmental permitting. Through the following examination of historical exploration activities, it is clear that these activities are directly related to economic stimulus, mostly measured by downturns in the mineral industry. Other factors that influence the success of exploration advancing to feasibility and new mine development includes the ownership of the mineral claims, which also changes under these economic influences and the crucial role of interactions between the Company, the Crown and First Nations. The Marathon PGM-Cu deposit is hosted within the Eastern Gabbro Series of the Proterozoic Coldwell Complex, which intrudes and bisects the much older Archean Schreiber-Hemlo Greenstone Belt. The sub-circular complex has a diameter of 25 km and a surface area of 580 km2 and is the largest alkaline intrusive complex in North America (Walker et al., 1993). Mineralization at the Marathon PGM-Cu deposit is part of a very large magmatic system that consists of at least three cross-cutting intrusive olivine gabbro units that comprise the Eastern Gabbro Series of the Coldwell Complex (Figure 3.2.4-3). In order of intrusion, the three gabbroic units consist of (1) Layered Gabbro Series, (2) Layered Magnetite Olivine Cumulate (LMOC) and (3) Two Duck Lake (TDL) Gabbro. The relative size and abundance of the gabbroic units decrease in the order Layered Gabbro Series>TDL Gabbro>>LMOC. Late quartz syenite and augite syenite dikes cut all of the gabbros but form a minor component of the intrusive assemblage.

May 1, 2010

By Michael J. Sapko, Ellsworth R. Spencer, Frank J. Perzak

"The fire resistance of several mine conveyor belts is evaluated using a new belt-flammability apparatus developed by the U.S. Bureau of Mines. The test apparatus, experimental details and a calculated flammability index (FI) are described.The FI values are useful for ranking the fir e resistance of mine conveyor belts. Values are determined using parameters readily measured with thermocouples, high-temperature flow probes and a methane-oxygen torch, all of which are components of the Bureau&apos;s new test apparatus. The FI varies directly with the flame-spread rate and the rate of heat release during burning and varies inversely with the critical (minimum) ignitor energy output.The fire-resistance ranking of nine different belt types using this moderately scaled apparatus is compared with available full-scale data on belt fires. This comparison shows that the ranking based on the FI is consistent with the full-scale data.IntroductionFull-scale fire hazard evaluations of mine conveyor belts are not easily related to the properties usually measured in small-scale flammability tests. The inadequacy of small-scale belt fire tests has been demonstrated in works by Mitchell, Warner and Reinke.Mitchell and Warner showed that certain neoprene (NP) and polyvinyl chloride (PVC) belts, which had been approved by the Code of Federal Regulations 30 CFR 18.65, were nevertheless capable of propagating flame over their entire length when full-scale fire conditions were simulated. Comparable results were also observed by Reinke at the Tremonia experimental mine in Dortmund, West Germany, where all belts burned in full-scale tests even though they passed the small-scale tests. Only by reducing the severity of the full-scale test could these fire-resistant belts be grouped on a pass-fail basis."

Jan 1, 1982