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By R L. Cheesman

An extensive Precambrian iron-formation lies about 2,000 ft. beneath post-Precambrian rocks in the Fort a Ia Corne Forest Reserve, south of Choiceland, Saskatchewan. The geology, deduced from limited drill results and from some geophysical observations, indicates that the deposit is a characteristic magnetite iron-formation, not uncommon in the exposed Precambrian of Saskatchewan, but also shows certain interesting features of faulting and pre-Paleozoic weathering which have given rise to a pre-served detrital deposit of hematite. The body is of ore grade and of sizeable proportions. T HIS paper is presented in order to set forth the interesting geological features of a Precambrian iron deposit located beneath the cover rocks of the Great Plains region and to comment upon the methods of discovery and interpretation of the nature of the body. The Choiceland iron deposit is located in the Fort a Ia Corne Provincial Forest Reserve, some 15 miles south of the town of Choiceland, Saskatchewan. Choiceland is

Jan 1, 1964

By E. J. Wasp, T. L. Thompson, T. C. Aude

The paper will deal with some of the more important technical aspects of slurry pipelines as they apply to the mineral field. In addition, the use of these technical concepts in arriving at realistic economic figures will be discussed.

Jan 1, 1970

By K. E. Waters, E. R. L. Espiritu, G. R. da Silva

"Rare earth (RE) elements are essential components of emerging green technologies. The increase in demand for these applications have driven the search and development of new rare earth deposits such as the Niobec project in Quebec, Canada. This deposit consists primarily of dolomite with significant amount of RE minerals bastnäsite and monazite, the primary sources of RE elements. Due to the minerals’ fine liberation sizes, flotation is commonly used as a concentration method. To develop an efficient process, the electrokinetic properties of the minerals must be understood. In this study, the surface properties of bastnäsite, monazite (RE minerals) and dolomite (a common gangue mineral) were investigated by zeta potential measurements. These measurements are affected by various ions present in solution; for bastnäsite, monazite and dolomite, some of these ions are H+, OH-, PO43- and CO32-. Dolomite, being a sparingly soluble mineral and a primary component of the ore, may be the greatest contributor of these ions in solution in the form of CO32- ions. Thus, different sources of CO32- ions (from dolomite dissolution and from Na2CO3) were investigated. The research work aims at elucidating how these reagents may influence the minerals’ surfaces. The results have shown that dolomite supernatant and sodium carbonate greatly affect the electrokinetic properties of each minerals. The addition of dolomite supernatant have resulted to relatively similar zeta potential of the minerals; while, sodium carbonate have affected them differently. These observations could be useful in efficient flotation of bastnäsite and/or monazite from bastnäsite-monazite-dolomite system.INTRODUCTIONThe increase in the demand for rare earth (RE) elements has driven the search and development of new deposits. Out of 53 rare earth projects in the world, 19 can be found in Canada (Hatch, 2015). These include the Niobec project of Magris Resources Company in Quebec. This deposit contains a significant amount of rare earth minerals (such as bastnäsite and monazite), with carbonates (such as dolomite) as the primary gangue minerals."

Jan 1, 2016

By John C. Leighton, C. O. Brawner, Doug Stewart

"Despite the availability of established, sophisticated methods for planning and designing stable slopes in rock, comparatively little attention is usually paid to the problems of carrying out the excavation. Blasting should be carefully planned to obtain optimum fragmentation as well as steep, stable working and final pit walls. The principal difficulty facing a blast designer is the lack of prior information about the many critical blasting characteristics of the rock mass. The common practise of trial-and-error lasting will eventually lead to a suitable program, but must be repeated time after time in variable geology. This frequently results in many blast-damaged slopes. Recent research indicates that monitoring drill performance will yield a Rock Quality Index which correlates to a Powder Factor value. The drilling can provide a continual supply of data, reflecting changes in the rock mass which enables the selection of an economical powder factor.IntroductionWhen planning to excavate a large-scale rock slope, engineer s will generally spend considerable effort to produce a safe, feasible and economical design. Much time will usually be spent on the field map ping, 'structural geologic studies, surface and subsurface hydrology, determination of strengths and effective friction angles of discontinuities, and finally checking stability with the aid of mathematical and analytical models. If the rock cut is to be along a transportation corridor, the prime justification for this time and effort is to produce a clean, stable slope which will be safe for those travelling or working beneath it. For the walls of an open-pit mine, there is the additional economic incentive to maintain the steepest stable slope angle for the minimum stripping ratio (Stewart and Kennedy)."

Jan 1, 1982

By T. W. Wlodek

"AbstractIn this paper a new type of durable 'spiral-rolled' drill set is introduced and its performance discussed. Efficient and economical mine drilling-depends to a great extent on durability of the drill-set employed. Premature failure of this element damages the drill bit and is costly when tungsten carbide bits are used.Time of drilling of 'spiral-rolled' drill sets introduced at present in Canada is considerably larger than for the presently used drill steel, but laboratory simulated service tests and practical field tests show that the 'drilling life' of the spiral-rolled drill set is several times that of ordinary drill steel.Some features of differential plastic deformation and differential surface rolling, so called 'spiral-rolling', are given.Relations between the drilling machine drill set and characteristics of the ore are discussed. The effect of shims on conical drill rod attachments, the mechanism of failure of drill steel, .and stresses during mine drilling, are analysed.IntroductionIN MINE DRILLING operations, the main interests are: the drilling machines as a source of working energy, the drill set as the tool transferring the working energy to the cutting edges of the bit, and, finally, the drilling characteristic of the .ore or waste rock.This paper includes a review of the possibilities of metallurgical and mechanical improvements in the drill set, with particular attention to drill steel and the attachments.For economical and efficient mine drilling operations, a durable drill rod, attachment, and drill bit are essential. Premature failure of any of these parts interferes with mining operations and is costly."

Jan 1, 1955

By E. R. Olson

The introduction gives not only a historical background but also touches on shaft sinking and surface construction and gives some general information on the Potash Conservation Regulations which the Saskatchewan government introduced in 1969. It also gives information on the corporate and local organization of Alwinsal Potash.

Jan 1, 1972

By Jack G. Hazan

The Critical Path Method is the modern scientific answer for solving the planning and scheduling problems inherent in today's complex projects. With this method, nothing is left to chance. All resources are controlled and kept to the minimum. The various phases are properly planned and strategically determined. Optimum conditions are evaluated for the most economical and fastest way to complete a definite project. The method must be fully understood and implemented with positive data and continuous feedback to obtain the best results. This paper covers the various aspects of the Critical Path Method and mentions some of its applications in the mining and metallurgical fields. T 0 progress to a higher state of human welfare necessarily involves sacrifices. The greatest sacrifice is to relinquish social freedom in favour of economic freedom. In the old days, for example, a cobbler was free to work at whatever time of the day he chose; today, he can't. He is now forced to adapt himself to environment and to work at stand-

Jan 1, 1965

By N. Bakhshizadeh

In this investigation, the aging effect on creep behavior of A12024-10%SiC composite fabricated by powder metallurgy was studied. P/M bars were manufactured by hot powder extrusion method at 450°C with a ratio of 16 to 1. Creep specimens were over-aged at 187 ºC for 43 h. It was found that almost full density composite with relatively homogenous distribution of reinforcing particles throughout the aluminum alloy matrix could be attained by direct powder extrusion process. Creep tests were conducted at temperatures from 275 to 325°C under stresses from 25 to 60 MPa. The analysis of the creep mechanism determined that dislocation glide was the predominant mechanism of plastic deformation. The activation energy of the creep process was found to be higher than that of lattice self-diffusion in pure aluminum.

Jan 1, 2007

By W. B. Xie

The hardening behaviour and microstructure evolution of Cu-30Ni-30Mn alloys aged at 350 °C has been investigated utilizing optical microscope, scanning electron microscope, transmission electron microscopy and Vickers hardness tester. The results show that the discontinuous precipitation of NiMn phase results in a remarkably hardening effect in Cu-30Ni-30Mn alloy during aging at 350 °C. The maximum hardness (~494HV) is attained in the sample after aged for 48 h. The NiMn precipitates are ordered and have a face-centered tetragonal structure. The coherent orientation relationship between the NiMn precipitates and Cu matrix is (220)Matrix // (220)P, [1-1-2]Matrix // [1-1-2]P. In addition, there is a linear relationship between hardness and volume fraction of the discontinuous precipitation, which indicates that the hardness increment of Cu-Ni-Mn alloys aged at 350 °C is attributed to the microstructure characteristics of discontinuous precipitation. The high strength of discontinuous precipitation colony is caused by the formation of nanoscale NiMn precipitates with a lamellar structure in discontinuous precipitation. INTRODUCTION Cu-Ni-Mn alloys are attractive candidates for oil drilling, aerospace and energy applications due to their high elasticity, high strength and excellent corrosion resistance (Sun et al., 2009; Liu, Yang, Xia, Jiang, & Gui, 2016). The high strength of the Cu-Ni-Mn alloys is mainly attributed to the precipitation of NiMn phase (Shapiro, Tyler, & Lanam, 1974; Xie et al., 2015). The uniformly dispersed nanoprecipitates formed by continuous precipitation can impede dislocation movement, and thereby lead to a significant improvement in strength of traditional precipitation-strengthened alloys. However, it is reported that there are two precipitation types observed in Cu-Ni-Mn alloys, namely, continuous precipitation and discontinuous precipitation (Shapiro et al., 1974). The discontinuous cellular colony with a lamellar structure nucleates at grain boundaries, and progressively grows inward the grain on the process of discontinuous precipitation (Ng, Bettles, & Muddle, 2011). It is found that the discontinuous precipitation can occur in many Cu-based alloys, such as Cu-Ni- Mn alloy (Shapiro et al., 1974), Cu-Be alloy (Monzen, Hasegawa, & Watanabe, 2010) and Cu-Ni-Sn alloy (Zhao, & Notis, 1998). Many studies consider that the discontinuous precipitation results in a detrimental effect on hardness and strength, and the discontinuous precipitation occurring during aging treatment should be suppressed (Markandeya, Nagarjuna, & Sarma, 2004; Semboshi, Sato, Iwase, & Takasugi, 2016). The mechanical properties can also be improved by discontinuous precipitation in AZ91 magnesium alloy (Tamura, Kida, Suzuki, & Soda, 2009) and AM30 magnesium alloy (Saikawa et al., 2012). Jun (2017) found that the reduced interlamellar spacing of precipitate fibers in discontinuous cellular colony leads to a significant increase in hardness. Indeed, the strengthening contribution of discontinuous precipitation is similar to that of continuous precipitation in Cu-20Ni-20Mn alloy. Discontinuous precipitation of NiMn phase can provide a significant strengthening effect in Cu-Ni-Mn alloys.

Jan 1, 2019

By Gaston Gingras

"IntroductionL'entretien de l'equipement minier dans les mines à ciel ouvert est une activité qui est aussi vieille que I'existence des mines et qui a progressé au cours des années pour suivre l'évolution des techniques d'exploitation. Lors de la mise en usage de s premières pelles à la va peur, celles-ci étaient généralement entretenues par I ‘équipe de quatre hommes qui était responsable de son opération. Pour les travaux plus compliqués ils utilisaient les services de machinistes qui eux savaient comment réparer Ie moteur à vapeur et couler des coussinets de ""babbit"". Les premières pelles diesel étaient entretenues de la même façon mais pour les réparations au moteur, on devait recourir au représentant du manufacturier qui était Ie seul à avoir les compétences nécessaires.Ce n'est vraiment qu ‘après la deuxième guerre mondiale que I ‘usage de l'équipement mobile s'est répandu dans les mines à ciel ouvert pour débuter les extractions selon les méthodes que I'on connaît aujourd'hui.L'entretien de l'équipement minier de façon organisée à débute avec I ‘usage de ces machines dans nos mines. Ces machines étaient un peu primitives, petites et pas très dispendieuses a I'achat. Même si la disponibilité était basse, elles fournissaient quand même un rendement qui en ces temps était acceptable. L’organisation de I ‘entretien de cet équipèrent était assez primitif et n'occupait qu'une place secondaire aux yeux de la direction de la mine."

Jan 1, 1988

By W. M. Tupper

Municipal governments recognize the importance of aggregates in the local economy and the need to manage this resource in the interest of the public good. They have encountered problems with regulating the industry and the dichotomy between the urban need and the rural source. They have suffered from a lack of financial benefit, an adequate aggregate inventory, provincial strategy, economic information and public understanding. A provincial strategy for ensuring the availability of aggregate supplies to developing areas of the Province is essential. The Province should also be responsible for licensing, research, technical expertise on rehabilitation, public education and financial assistance. Upper-tier municipalities (regions or counties) should assume responsibility for resource management, including resource availability, demand characteristics, truck routing, phasing of resource development and sequential land-use planning. Area municipalities (towns and townships) can best determine the social and environmental impact of a specific aggregate development proposal and should therefore have the primary responsibility for the location of new pits and quarries. They should also have the authority to supplement provincial regulations concerning operating standards and the phasing and standards of site rehabilitation.

Jan 1, 1978

By A. H. Lang

THE recent production of important quantities of high-grade muscovite at the Purdy mine, near Eau Claire, Ontario, bas brought that district into prominence and bas added another strategic mineral to the list of Canadian products. The discoveries are thirteen miles west of Mattawa and about two miles north of the Trans-Canada highway and the Canadian Pacific railway. HISTORY Clear mica of low power factor is in considerable demand in Canada and in the United States for war purposes such as radio and telephone condensers, aircraft spark-plugs, radio tubes, and transformers. Some muscovite (white mica) bas been produced in North Carolina and New Hampshire, but the United States trade bas depended largely on importations of muscovite from India and of phlogopite (amber mica) from Madagascar. For many years Canada bas been a substantial producer of phlogopite, but was unable to compete extensively in the United States with importations from abroad. Canadian production of muscovite bas been negligible as no important deposits were known. Ever since the construction of the Canadian Pacific railway, attempts have been made from time to time to mine the pegmatite dykes in and near the Eau Claire area, but, although some feldspar has been mined, no appreciable muscovite was produced. Lace in 1941, J. Purdy and H. MacDonald discovered a dyke containing large crystals of high-grade muscovite from which they are reported to have sold $700 worth of mica. They recorded claims 35974 and 35975 in December, 1941, and claim 36095 in May, 1942.

Jan 1, 1943

By John F. Gartner

"Traditionally, the geologists of Canada have been occupied with the tasks of finding new mineral bodies, locating gas and oil fields or hunting for economic deposits of industrial minerals. A very minor percentage of graduate geologists have applied their skills to solution of the ""urban blight"" or employing their understanding of ""Nature"" for the optimum use of land by mankind. However, things are changing quickly. The role of the geologist in the planning process is being established. It is an exciting time! Geologists are now being consulted on a wide range of urban planning problems. These vary, tor example, from assessment of the geological environment for the new communities of Erin Mills and Meadowvale, which will have total populations in excess of 100,000 people (truly a satellite city), to a complete geological/ geohydrological assessment of the new sanitary landfill for the city of Guelph.Use of geologic techniques and methods for urban studies must be enhanced with certain skills not taught, in the past, to the geologist. These include airphoto interpretation, soil mechanics, geohydrology, municipal engineering and highway engineering to mention a few. The geologist has the unique training to assess the natural environment and to discover, warn and explain the implications of man's attempt to command his environment."

Jan 1, 1972

"Previous studies on the effect of polytetrafluoroethylene addition during chalcopyrite leaching under conditions similar to those of the CESL process have reportedly resulted in complete leaching of the copper without the need for grinding of the flotation concentrate. However, these studies employed a pulp density of only 1% and finely sized PTFE particle that required the use of high impeller rotation rates that are not sustainable at an industrial scale. This paper explores the performance of 1/8” diameter balls of PTFE, that readily sink in the leach solution, on leaching performance at impeller rotation rates and ore pulp densities more typical of industrial practice. Possible routes for separation of the PTFE from the leach residues and their regeneration for recycling back to the leaching stage are also discussed.INTRODUCTIONChalcopyrite, CuFeS2, is the most important primary sulfide source of copper. While pyrometallurgical smelting of chalcopyrite remains the only widely accepted route for treating chalcopyrite concentrates, several medium temperature pressure oxidation processes are claimed to be economically feasible (Muir & McDonald, 2007). Among these, the CESL process has been extensively piloted and demonstrated at the prototype scale. The overall process chemistry of the CESL process may be summarized as follows (Marsden & Wilmot, 2007):4CuFeS2 + 5O2 + 4H2SO4 ? 4Cu2+ + 4SO4 2- + 2Fe2O3 + 8S0 + 4H2O (1)4CuFeS2 + 17O2 + 2H2SO4 ? 4Cu2+ + 10SO4 2- + 4Fe3+ + 2H2O (2)Though copper extractions of over 95 % are achieved, the CESL process requires extra grinding of the concentrate (Muir & McDonald, 2007). This is because leaching is conducted at temperatures around 150 °C, where the elemental sulfur produced is molten and grows thicker on the mineral’s surfaces as oxidation progresses, creating an increasingly large barrier for mass transport. In addition, the sulfur is sticky and tends to cause the mineral particles to agglomerate, effectively halting further oxidation of the particles that end up embedded within the agglomerates. Consumable surfactants, such as ligin sulfonate, have been shown to be effective at avoiding agglomeration, but they are not effective at removing sulfur from the minerals. Hence, their use does not obviate the need for fine grinding."

Jan 1, 2012

By K. Sawamukai, S. Ogasawara, D. Umenai, T. Tsuruta

"Removal of cobalt, strontium or cesium ion from the aqueous solution containing each metal ion only using microorganism was examined. Arthrobacter nicotianae which had a high ability to remove cationic metal ion was used for the removal of each metal. The removal of cobalt, strontium or cesium using A. nicotianae cells was affected by the solution pH, concentration of metal ion, and cell amount. The effects of above mentioned factors on the removal of each metal and time course of strontium from the solution containing each metal only using A. nicotianae cells were reported in this paper. INTRODUCTIONRadioactive elements, such as cesium, iodine, strontium, plutonium, barium, cobalt, lanthanum, yttrium, and tellurium, were detected around Fukushima Daiichi nuclear power plant, which was damaged by the magnitude 9.0 earthquake and the tsunami followed.The removal of radioactive elements from contaminated sources is a worthwhile subject to investigatein terms of environmental control. Research efforts have been especially concentrated on studying microorganisms that remove uranium including bacteria (Andres et al, 1993, Hu et al, 1996, Marques et al, 1991, Strandberg et al, 1981), actinomycetes (Byerley et al, 1987, Friiss and Myers-Keith, 1986, Golab et al, 1991), fungi (Byerley et al, 1987, Galun et al, 1983a, Galun et al, 1983b,Tsezos and Volesky, 1981, White and Gadds, 1990) and yeasts (Strandberg et al, 1981, Schmate II et al, 1978).We have investigated removal and recovery of uranium from aqueous systems using microorganisms isolated from uranium mines. We identified some strains of bacteria with extremely high uranium removing abilities (Sakaguchi et al, 1996), and thus, the microbial biomass may be considered as an adsorbing agent for the removal and recovery of uranium and heavy metals present in aqueous systems around Fukushima Daiichi nuclear power plant.In the present study, we screened various species and strains of bacteria, actinomycetes, fungi, and yeasts for their ability to adsorb uranium (Tsuruta, 2002). Basic features affecting uranium adsorption?co-existing cations and anions, cell amounts, pH, and the adsorption time course?by Arthrobacter nicotianae cells, which adsorbed the largest amount of uranium, were also investigated. In addition, we examined the removal of an other actinoid element, thorium ion, which may be present with uranium in refining effluents.In this paper, the removal of cobalt, strontium, or cesium from the solution containing each metal ion using A. nicotianae cells is discussed."

Jan 1, 2012

By Sunil S. Gandhi

"The Mountain Lake deposit is a tabular sandstone-type uranium deposit, hosted by the basal unit of Middle Proterozoic Dismal Lakes Group. Uranium occurs mainly as sooty pitchblende disseminated in stratiform lenses within gently dipping quartzose sandstone. It is associated with copper sulphides, pyrite, hematite, and traces of nickel and cobalt arsenides and of silver.Exploration HistoryUranium showings on the PEC claim group were discovered during 1969 by an airborne radiometric survey carried out over the Dismal Lakes-Great Bear Lake area by Aquitaine of Canada Limited (Bizard and Salat, 1969). Some drilling was done in the vicinity of the showings in 1975 by the company under a joint venture with Eldorado Nuclear Limited but the results were not encouraging (Hassard and Woollett, 1975). During 1972, Trigg, Woollett and Associates Limited conducting surveys for Imperial Oil Limited, discovered numerous high-grade radioactive boulders scattered over a distance of several kilometres north and west of the showings, and the area north of the PEC claims was staked as the YUK claims (Ahuja, 1974). A systematic study of the boulder distribution and Pleistocene geology suggested a source additional to the showings. More intensive exploration followed, and in 1976 drilling just north of the PEC claim group boundary intersected the main deposit at a depth of 75 m to 150 m, beneath overburden up to 60 m thick. Part of the deposit extends into the PEC claim group which is under exploration by the Aquitaine-Cominco Joint Venture.The following brief description is based on the presentations in 1978 by F. Hassard of Trigg, Woollett and Associates Limited at the Geoscience Forum in Yellowknife, and by S.S. Gandhi of the Geological Survey of Canada at the Mineralogical Association of Canada Uranium Short Course in Toronto."

Jan 1, 1986

By J. Petit, P. Girard, A-M. Gilbert, D. Faucher

L&apos;annee 2000 a été une année stratégique et significative pour l&apos; Aluminerie de Bécancour dans la réduction des gaz a effets de serre. L&apos; équipe s&apos; etait donne comme defi un jour d&apos;arriver a l&apos;objectif de zero effet d&apos;anode dans les sa11es de cuve (720 cuves au total). Le cha11enge s&apos;averait tres ambitieux car la fa<;on d&apos;alimenter une cuve d&apos;electrolyse pour obtenir son maximum de rendement faraday est de travailler le plus pres possible de l&apos;effet d&apos;anode pour eviter l&apos;embourbement de ce11es-ci. Ceci signifie que techniquement nous a11ons en moyenne, quotidiennement, 12500 fois pres de l&apos;effet d&apos;anode sur !&apos;ensemble de nos 720 cuves qui produisent aujourd&apos;hui environ 405 000 tonnes d&apos;aluminium liquide annuellement. Des 695 kg equivalent en C02 par tonne d&apos;aluminium produite en moyenne annue11ement, de 1990 a 2000, nous en sommes rendus ace jour a environ 35 kg equivalent en C02 par tonne produite. Nous sommes pres d&apos; atteindre notre objectif mais les demiers gains sont plus difficiles a atteindre. Les strategies d&apos;automatisme et d&apos;informatique, incluant l&apos;aspect de !&apos;implication humaine sur les bonnes pratiques de travail sur les cuves d&apos;electrolyse, sont les cles de ces resultats.

Jan 1, 2006

By J. E. Hawley, R. C. Hart

"The Preston East Dome gold mine is in the southeastern part of Porcupine district, Ontario, 5 miles southeast of Timmins, and immediately south of the property of Dome Mines, Limited.The claims now owned by this Company were originally staked in 1909. After the property had remained dormant for many years, the present Company was organized in 1936 to resume development operations. Two shafts had been sunk: at the time of the early work on the claims, but lateral work from these failed to reach the ore deposits. A successful diamond drilling campaign undertaken under the direction of D. G. H. Wright, however, was followed by the sinking of a five-compartment shaft arid the erection of a mill. From the start of operations to the end of 1944, 1,292,000 tons of ore averaging $11.60 in gold a ton have been mined.An outstanding feature in this mine is the occurrence of the major gold deposits in quartz porphyry intrusives, though minor deposits are also found in the adjacent Keewatin volcanics. Most of the ore occurs in fractures, but the filling was accompanied by varying degrees of replacement of schistose wall-rocks. The ore deposits may be classified as:"

Jan 1, 1954

By G. O. Oniyide, H. Yilmaz.

"This paper presents the result of the research done on the effect of temperature on the dilatancy of rocks from the Bushveld Igneous Complex (BIC), where the South African Platinum mines are located. The BIC has higher virgin rock temperature (VRT) than the gold mines of the ‘Witwatersrand Basin Complex’. If the platinum mines advance to ultra-deep levels as the gold mines, since the Merensky Reef has been reported to extend beyond 5km, then the virgin rock temperature at 5 km below surface would be approximately 140oC. Hence, there is a need for the investigation of rock behaviour at high temperatures. Five different rock types (norite, leuconorite, mottled anorthosite, pyroxenite and chromitite) were tested in a 2600 kN servo-controlled multi-purpose triaxial testing machine. The tests were done at a constant strain rate of 5 x 10-1 S-1 and a confining pressure of 10 MPa within temperature range of 20 °C (ambient temperature) to 140 °C. The results show a general strength reduction and increasing dilation angles with increasing temperatures. The results also demonstrate that dilation angle is close to the internal friction angle at lower temperatures; however, they are greater at higher temperatures.INTRODUCTIONMany challenges are faced with increasing depth of mining in underground mines. The most obvious are heat, in-situ stresses and those associated with logistics. Issues related to underground heat have mainly focused on the side effect of heat on workers' health, increasing production costs as a result of higher cost of ventilation. The effect of increasing temperature with increasing depth on the behavior of rock has not been given much consideration. Generally, gold mines in South Africa are deeper than the platinum mines but the latter have higher temperature gradient, which makes the platinum mines to be warmer at similar mining depths. Although the study of the effect temperature on the behaviour of rock can be beneficial to both gold and platinum mines, the focus of the research is limited to the platinum mines because of their higher temperature gradient. Donoghue (2004) stated that the virgin rock temperatures (VRT) and air temperatures increase with depth, due to the geothermal gradient and auto-compression, that is, compression of air by its own weight."

Jan 1, 2015

By Alex Matheson, Nick W. D. Massey, Peter T. Bobrowsky

Crowing pressures on aggregate resources include diminishing reserves, high transportation costs, sterilization and land use conflicts. In the absence of detailed resource knowledge for a particular region, aggregate resource potential maps provide the best "first approximation" regarding the surficial distribution of sand and gravel. The 1:50 000 scale Level Ill aggregate potential map integrates several important factors which influence the management of sand and gravel. Data used to generate this type of thematic map is readily available in most areas, fieldwork required is minimal, there is a logical quantitative evaluation of the data layers and integration is easily accomplished on a desktop PC-based platform. Also the aggregate potential map, with its focus on identifying areas of potential future aggregate exploitation as well as present inventory, provides a useful tool for the aggregate explorationist.

Jan 1, 2001