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By R. Pot

"IntroductionTHE PURPOSE of this paper is to discuss briefly the main logging and testing devices presently at our disposal, to point out some of their limitations, and to suggest possible improvements of the techniques.Some of the more important devices .are those that are used in:(1) Coring(2) Formation testing(3) Electric well logging(4) Radioactive well logging(5) Measuring of bottom hole pressures(6) Sampling of reservoir fluidsThe first four of these procedures are concerned with the well while it is in the process of drilling. The last two are carried out as soon as possible after a well has been brought into production and .at intervals during its life. My remarks will be concerned mostly with certain aspects of formation testing. The reservoir engineer is dependent on the information derived from these operations in order to obtain a clear picture of the conditions in a reservoir and to enable him to assess and forecast its future behaviour.Since any calculation is no better than the data on which it is based, not enough emphasis can be placed on the necessity for the testing and logging equipment to be of the highest quality and for the analysis of the results obtained to be thorough."

Jan 1, 1952

By R. K. Carnochan

MANY improvements have been made in recent years in the milling of industrial minerals and it is the purpose of this paper to review some of the more important innovations that are now being used in the preparation of these products. Some of the observations which will be made have been prompted by what was seen on a recent trip to industrial mineral milling plants in the north and central sections of the eastern United States. The flotation plants visited were those of the Valley Forge Cement Company at West Conshohocken, Pa., the International Agricultural Corporation at Mount Pleasant, Tenn., and the Aluminum Ore Company at Rosiclare, Ill. Besides these, sand plants in Pennsylvania, West Virginia, and Ohio, coal-cleaning plants in Pennsylvania, pyrophyllite, mica, feldspar, clay, and kyanite plants in North Carolina, and a zinc mill and the Tennessee Valley Authority ceramic laboratory in Tennessee were visited. The milling of industrial minerals can be considered under three broad headings, namely, crushing, grinding, and purification. Usually there is both a separation and grinding problem in treating an industrial mineral, but the problems are distinct, although sometimes a separation is made while grinding, as in the case of a Raymond throw-out mill, which grinds and at the same time throws out most of any hard material present in its feed.

Jan 1, 1939

By Horace Freeman

Introduction In the aggregate, directly and ?indirectly, the pulp and paper industry ? consumes very large quantities of a variety of minerals, or compounds prepared from minerals. This is especially true in the manufacture of news-print, but fine papers, also, account for some of this consumption, in the processes of loading, coating, and otherwise improving the finish. The more important of the minerals used in the industry in Canada are briefly dealt with in the following pages. The list is by no means exhaustive, however. Thus, barite, lithopone, zinc oxide, zinc sulphide, and titanium oxide are used in small quantities in Canada in filling and coating paper. Up to the present time, however, the quantities of these materials used in the paper industry have not sufficed to encourage their manufacture in Canada. In the case of barite (barium sulphate)-or of witherite (barium carbonate)-it may be said that, should deposits of commercial size be discovered in Canada, the ore would have considerable export value, for use in the paper and other industries. China-Clay (Kaolin) Considerable quantities of china-clay are used for brightening and improving the finish of paper, and there is a growing tendency to use larger amounts of this material in newsprint manufacture. No china-clay suitable for paper manufacture is at present produced in Canada, but samples have been forthcoming recently from a deposit near St. Remi d'Amherst, Labelle county, Que., about thirty miles north of the Ottawa river and approximately midway between Montreal and Ottawa, and plans are under way to conduct large-scale tests with this material. Present sources of supply are the United States, England, and Russia.

Jan 1, 1934

By D. K. Sarkar, Ying Huang

"Superhydrophobic thin films were fabricated on aluminum alloy substrates by chemical etching followed by passivation with organic acid molecules; (ii) electrophoretic deposition (EPD) of functionalized ZnO nanoparticles and (iii) electrodeposition of organic-inorganic composite materials. The physical and compositional analyses of the deposited thin films were characterized by SEM, FTIR, XRD as well as contact angle goniometer. The contact angle and surface roughness of the superhydrophobic surfaces prepared by the chemical etching process were found to be 156° and 2.29 µm, (ii) by the EPD process were found to be 155° and 4.54 µm and (iii) by the electrodeposition process were found to be 159° and 7.11 µm, respectively.The corrosion properties were analyzed with both polarization and electrochemical impedance spectroscopy (EIS) in NaCl aqueous solutions. The results demonstrate that the superhydrophobic thin films on aluminum alloy substrates display better anti-corrosion behavior than the as-received aluminum substrate. The comparison of results pertaining to the compositional and corrosion properties of these thin films on aluminum will be discussed in this work.INTRODUCTIONSuperhydrophobicity is defined as a surface property which provides non-wetting characteristics with a water contact angle larger than 150°. It is observed that the creation of certain micro-nanoroughness structures promotes the entrapment of air in the spaces of the rough surface morphology. In addition, lowering the surface energy helps to reduce the affinity of water drops to the surface, thereby weakening the water-surface interaction. Recently, various fabrication methods for superhydrophobic surfaces have been explored (Sarkar, 2010, Huang, 2010, 2011, 2013, 2015a, 2015b), such as the sol-gel process (Brassard, 2011), plasma treatment (Marchand, 2013), chemical vapor deposition (Zheng, 2009), chemical etching (Saleema, 2011), electrodeposition (Ying, 2011) and electrophoretic deposition (EPD; Huang et al., 2015b)."

Jan 1, 2016

By Alfred B. Annor

The introduction and application of paste backfill over the past two decades has resulted in substantial benefits being realised by many backfill reliant mining operations who have used this technology. Paste preparation over this time period has relied basically on mechanical dewatering approaches that have included the use of centrifuges, thickeners, and vacuum and pressure filtration. In large bulk mining operations, this method of paste preparation has usually involved the construction of big and complex surface plants to meet large tonnage demands. These large plants usually have attendant high capital, maintenance and operating costs. The application of paste backfill in narrow-vein mining requires more flexibility in terms of fill preparation, transportation and placement. The method of paste fill preparation should take into consideration low manufacturing and operating costs, ability to use existing facilities at mine sites, simplicity of operation and flexibility of preparing fill over a broad range of consistencies. This paper will review alternative paste fill preparation methods and indicate those that might be better suited to narrow-vein mining.

Oct 1, 2001

By L. V. Bell

"The gold deposits of the Caribou mine are representative of those of the Province of Nova Scotia as a whole. The ore shoots within the deposits, in common with those elsewhere within the Province, are associated usually with interruptions or irregularities in the broader and uniform fold structures. The structural factors localizing ore deposition as applied more specifically to the Caribou mine are demonstrated chiefly by the close relationship of the two principal ore shoots, known as the main orebody and the 'high-grade' vein, with a pitching drag fold developed in the southeast limb of the major northeast-southwest trending anticlinal fold or elongated dome that constitutes the primary structural feature of the Caribou gold district. It is of interest to note that the evidence indicates that this drag fold, in common with other folds subsidiary to the primary fold, formed as a result of movement similar in nature to that which caused the primary fold itself. Presumably, therefore, these folds are coincident in time.The property described here as the Caribou mine is an amalgamation of two adjacent properties formerly known as the Ross and the Nova Scotia Gold, but which since 1934 have been controlled and operated as a unit by The Consolidated Mining and Smelting Company of Canada, Limited. The Caribou mine is situated in the Caribou gold district about 45 miles to the northeast of the city of Halifax and about 6 miles to the north of the Moose River gold district.The history of mining at Caribou dates back to 1867. The first recorded gold production is for 1869. From 1869 to 1933 the gold produced from the mines of the Caribou district aggregated 47,249 oz. from 93,234 tons of ore treated. The grade of the ore on the basis of the gold actually recovered from the district would thus average 72 oz. gold a ton, which, as will be noted from the following, is precisely the grade of the ore treated from the Caribou mine during operations by The Consolidated Mining and Smelting Company. These operations commenced in September, 1934, and milling on a commercial basis was under way during 1938. Since that time production, apart from a short period in 1945 during which efforts were concentrated on development work, was continuous to early in 1947, when the mine closed down owing to exhaustion of the known orebodies. Gold produced from the Caribou mine by The Consolidated Mining and Smelting Company from September, 1934, to the close of 1946 aggregated 43,205 oz. from 90,754 tons of ore milled; the grade of ore treated averaged 0.50 oz. gold a ton. The indicated average grade of O.S oz. gold a ton for the ore of the Caribou district throughout its mining history ranks somewhat higher than the 0.37 oz. a ton average for the ore milled to date from the several gold districts throughout the Province as a whole according to the production statistics of the Provincial Department of Mines."

Jan 1, 1954

By Wei Yingchun

Based on the deep burial depth of coal deposits in Huainan-Huaibei coalfields, Anhui Province, China, this paper puts forward the concept of partitioning of coal deposits according to occurrence conditions. This process is controlled by tectonic forces. The classification scheme of coal deposits exploration types is presented according to occurrence and mining conditions of coal deposits as viewed from the perspective of deep coal exploration properties. The principles underlying geological exploration services for the resources development are incorporated. There are six exploration types of coal deposits in the Huainan and Huaibei coalfields. Exploration models tailored to different types of exploration have been established and exploration strategies corresponding to different exploration models have been proposed. Steady-state temperature must be measured for the deep heat-harm type of coal deposit. The sealing coring of mine gas samples should be performed for the high mine gas type of coal deposit. For coal deposits with complex structures, such as those located beneath nappes, coal-controlling structural styles must be performed. Existing data on shallow districts are very important to the research of folds and fault-block types of coal deposits beneath and peripheral to old and existing coal mine areas. For the types of fault-block coal deposits hidden by thick Cenozoic cover, particular attention must be paid to comprehensive use of research on regional coal occurrence law and geophysical methods. The present work promotes the exploration level of coal deposits in Huainan-Huaibei coalfields to best meet the need for sustainable development of the coal industry.

Aug 1, 2013

By H. H. Claudet

PROBABLY the first flotation mill for treating molybdenite ores was put into operation .in Norway during 1913, when the writer was employed to introduce and apply the Elmore vacuum flotation process at a mine in southern Norway. These operations proved successful and led to other similar installations in that country. It remained, however, for Norwegian engineers themselves to iron out their difficulties and establish the molybdenum industry on a basis which ultimately attained world importance. Just as today, an urgent demand for molybdenum arose during the world war of 1914-18. By 1916, many molybdenite properties were in operation in Canada and several small concentrating mills were under construction. At one of these, in the Ottawa Valley district, the opportunity came for applying the Elmore vacuum flotation process, using a flow-sheet similar to that adopted in Norway. Later, as one of the staff of the General Engineering Company, who had already developed a highly efficient flowsheet for treating molybdenite ores, using the Callow pneumatic flotation process, the writer devoted considerable time to research work and investigations on a number of molybdenite projects and deposits in eastern Canada. The bulk of Canada's production of molybdenite was coming at that time from the Moss mine at Quyon, Que., where concentration of the ore was effected by water-film flotation. It is of interest to note that this process, based on the principle of surface tension, had been developed and introduced by the late Henry E. Wood, of Denver, Colorado- one of the original owners of the Moss mine-at the time he was investigating the Elmore vacuum process in his Denver plant. The process, with certain modifications, was used at several other properties in eastern Canada, and notably in the ore dressing laboratories of the Department of Mines at Ottawa and in a plant at Renfrew, Ont., in both of which ore from deposits in various parts of Canada was treated, with recovery of very appreciable amounts o much needed molybdenite. During the summer of 1917, the water-film flotation mill at the Moss mine was dismantled and the plant was re-modelled by the General Engineering Company to include the Callow system. This installation, using improved flotation methods, was highly successful both as to recovery and grade of concentrate, and proved a decided advance in molybdenite concentration, a recovery of upwards of 90 per cent being obtained, with a concentrate grading over 90 percent MoS2.

Jan 1, 1944

By F. Ford, J. Dong

"Laboratory and miniplant testwork was carried out to reject uranium from an Iron Oxide Copper Gold (IOCG) deposit that contains an average of 60-70 ppm uranium with high variability. The dominate copper bearing mineral is chalcopyrite with minor bornite and trace covellite. The main gangue minerals are iron-rich chlorite, quartz and magnetite. The main uranium-containing mineral is uraninite (UO2). Downstream processes require the maximum uranium level of no more than 80 ppm in final copper concentrate.Mineralogical examination reveals that uraninite particles are finely disseminated with grain size of less than a few microns in the deposit requiring fine regrind in order to liberate uraninite from chalcopyrite particles. A lab flowsheet was developed to include ultrafine regrind of the rougher concentrate to the particle size of 80% passing 11-13 µm with up to four stages of recleaning in flotation columns. Finer regrind to 80% passing 5-6 µm may continue to improve liberation but does not decrease uranium level in the final concentrate. In each of the successive recleaning stages by flotation column after fine regrind, uraninite is rejected into the column tailings, with the final copper gold concentrate containing less than 70 ppm uranium from a feed containing 83 ppm uranium. The conceptual flowsheet was further tested in an integrated, continuous miniplant showing average 94% copper recovery with average 74 ppm uranium. The uraninite particles that report to the final concentrate are either locked with chalcopyrite or entrained as liberated particles of less than 5 µm in size."

Jan 1, 2016

By N. Saracoglu, R. H. Wallis, J. E. Betz, F. L. Jagodits, B. R. Krause

"Geophysical test surveys were conducted with various methods (EM, lP, gravity and magnetic) over the McClean uranium deposits of the Canadian Oxy- lnco Joint Venture. The result s were assessed to judge the contribution each method might make toward further discoveries of graphite-associated uranium occurrences.The best drill targets have proven to be discontinuities in graphitic conductors and locations where the tatter are intersected by fracture zones in the Athabasca. The tests demonstrated that the preferred combination of geophysical survey s is horizontal loop EM to locate graphitic conductors in the basement and VLF-EM to locate the fractures.IntroductionThe discoveries of the McClean North and South uranium deposit s (Fig. 1) are essentially geophysical successes resulting from drilling MaxMin delineations of INPUT airborne electromagnetic responses (Saracoglu et al., 1983). After the initial discovery in 1979, various geophysical methods, techniques and instruments were employed to test their effectiveness in this environment and to guide exploration for other deposit s of a similar nature in the remainder of the 260 km2 property.The McClean uranium deposits lie below 150 m to 180 m of overburden and Athabasca Group. Radioactive signatures might be expected; however, the Athabasca Group acts as a barrier to radioactive emanations. Fortunately, the uranium mineralization is associated with graphite in the crystalline basement. Prior drilling of ground electromagnetic anomalies confirmed that EM surveys could locate and out line basement graphitic conductors. However, as there were many anomalies, most of which could not reasonably be expected to be associated with uranium , there was need to identify additional parameters, related to mineralization, which could be detected geophysically and used to narrow the search."

Jan 1, 1986

By Bradford P. Simser

Increasingly sophisticated rock mechanic tools are becoming more and more available for today?s ground control specialist. However many problems are still beyond our ability to explicitly calculate or measure. There is often a gap between the ?art? and the ?science? of rock mechanics. This paper focuses more on the ?art?, giving relatively simple examples of underground observations and micro-seismic records to help explain ground control issues. Ground support techniques such as in cycle shotcrete with high pressure water scaling, mesh and bolting, pumpable resin bolts/cablebolting, and yielding bolts with load spreading straps are discussed. The use of primary/secondary type blasthole sequences in moderate to high stress situations is also discussed with several examples of the micro-seismic response to the stoping. Relatively erratic geology with high material strength contrasts is currently being mined with blasthole methods at Nickel Rim South. Although the mine is still in its? ?early? days, over 1 million tonnes has been extracted and some empirical experience is highlighted with potential longer term issues also being discussed.

Oct 1, 2010

INTINERARY ?What is SRI? ? How do we define good corporate social and environmental performance in the mining and petroleum industries? ? Why should you care? MJRA Inc. ? Established in 1992 ? Canadian Social Investment Database (CSID) launched in 1993 ? Jantzi Social Index launched in January 2000 ? created in 2000 SRI is ?the incorporation of social and environmental parameters into the investment decision making process.

May 1, 2002

By B. N. Church, A. R. Pettipas

"The second vertical derivative method of processing aeromagnetic data from low level helicopter surveys yields results correiatable with the known geology and may be utilized to indicate possible targets for future exploration in the Silver Queen and Equity Silver mines areas, near Houston in central British Columbia . The principal zones of alteration associated with mineralization, known from detailed mapping, are further delineated and extended in a way not possible by a cursory examination of the original magnetic data.IntroductionThe second derivative method of processing aeromagnetic data is a long established procedure used to enhance the short wavelength content of the magnetic fields. Some recent exam pies of the use of the second derivative technique have been published by Chandler (p. 385), Sun Yunsheng et al. (p. 424) and Yarger (p. 223) in Hinze, 1985. According to theory, the ""second vertical derivative"" is closely related to the rate of curvature of magnetic (or gravity) fields and is particularly useful in resolving and sharpening local anomalies. The contours on second derivative maps may coincide with important features such as lithological boundaries, faults and mineralized zones.In the Houston area, central British Columbia, aeromagnetic data supplied by local mining companies provide a ready base for analyses. Examples are data sets for the Silver Queen and Equity Silver mines centred 35 km and 34 km south and southeast, respectively, from Houston (Fig. 1), (Cochrane, 1970 and Church, 1985)."

Jan 1, 1990

By D. F. VanDine, H. George

"The possibility of spoil pile failure at the Kara Kara bauxite strip mine, Guyana, South America, is of major concern to the mine operators. The current mining technique requires the continuous operation of an 11 ms bucket capacity walking dragline on top of 18 metres of freshly spoiled uncompacted overburden material consisting of varying mixtures of kaolinitic clay and quartzitic sand. A field biased geotechnical study of undisturbed overburden and corresponding spoiled material has identified site-specific, non-linear correlations between vane shear strength, standard penetration resistance and spoil pile composition. Readily available geological exploration borehole logs has enabled a composite clay isopach map of the entire mining property to be drawn and critical areas to be zoned according to expected slope stability. Stability has been assessed using simple hand calculation techniques. Use of the resulting stability map provides the mine operators with a means of forecasting the need for appropriate preventative measures at varying stages of mine development, throughout the life of the mine.A similar investigation procedure could be employed at many presently operating and future strip mines.IntroductionThe Kara Kara bauxite stripe mine is located at Linden within the bauxite belt of Guyana in South America. The mining property covers a total area of 88 hectares of flat to gently sloping ground of which some forty per cent is being actively mined or being preparatorily stripped of overburden, prior to eventual mining (George and Gordon, 1979). The regional climate is tropic and humid. Temperatures vary from 16°C to 38°C and yearly rainfall averages 2600 mm, with at least 55 per cent of this precipitation occurring during the 'wet season' months of May to July and December to January."

Jan 1, 1983

By R. W. Thompkins

"PREFACEPart 1 of this paper, published in the September issue, covered the occurrence of uranium, radiation from uranium ores, the uranium series, radioactive theory, radioactive equilibrium and application to the radon series, the working level, the theory of emanation and diffusion, transport by thermal diffusion of radon emanating from porous rocks, and definitions.The October issue carried Part 2, which dealt with radiation theory applied to uranium ores, other radon migration factors, factors affecting the radon gas release rate, the measurement of radon gas emanation rates, the tunnel concept, variation of emanation rate with grade and estimating radioactivity from grade analysis.Part 3, in this issue, concludes the series by discussing the techniques for controlling radiation and providing some example calculations.17.0. Techniques for Controlling Radiation17.1. Altering the Factors In the Diffusion EquationIt has been noted that radon gas emanates from the surfaces of exposed ore to the mine atmosphere. The diffusion laws establish the rate of this flow. The fundamental relationship is that the rate of flow (J) is a function of the pore concentration and the distance from the surface. It is expressed as: []If any of these terms is varied, either naturally or artificially, the rate of gas emanation will be altered.Altering the Diffusion CoefficientThe literature describes many ways to lower the radon gas emanation rates which are dependent on changing the diffusion coefficient:1. A layer of ice on top of a tailings dam or on a soil.2. Humid clayey materials and swamped soils over a radon source."

Jan 1, 1982

By P .. D. Vaillancourt, D. F. Sangster

Several occurrences of disseminated galena, including a former producing mine, are found in Pennsylvanian fluviatile sandstone of the Salmon River Basin, Cape Breton Island, Nova Scotia. Detailed study of the distribution of these occurrences has revealed that highest galena concentrations are found in sandstone overlying channel-shaped depressions in felsic basement rocks. These buried depressions, in turn, correlate in position with modern streams in areas of basement exposure. This correspondence suggests that the latter are at least partially controlled by an exhumed Pennsylvanian topography. If this is correct, then several other streams in the area, lying on basement, may be used to locate possible undiscovered lead deposits in sandstones of the Salmon River Basin.

Jan 1, 1990

By P. B. Marchant

"Considerable gold and silver values are lost to flotation tailing from both the South ern Tail orebody and the Main Zone orebody,The underlying mineralogical assemblage of the two ore types is quite different. This paper describes the research strategy employed to determine an economical method to scavenge gold and silver from flotation tailing.Much of the unrecovered gold in the Southern Tail ore is associated with arsenopyrite while silver losses are probably as unliberated tetrahedrite and minor silver-bearing sulphosalts. Processing alternatives tested include bulk sulphide recovery by flotation and gravity, selective pyrite-arsenopyrite separation, cyanidation, and oxidation pretreatments such as pressure leaching and bioleaching to enhance cyanidation response. Gold losses in the Main Zone ore are more closely associated with silver-bearing minerals, pyrite, and siliceous gangue and consequently respond more readily to conventional tank cyanidation. The 5 300 tid carbon-in-leach circuit to treat Main Zone flotation tailing is described in detail.IntroductionEquity Silver Mines Limited's open-pit silver mine, a 70% owned subsidiary of Placer Development Limited, is located 37 km southeast of Houston in north central British Columbia. The deposit consists of two major ore zones, Main Zone and Southern Tail (Fig. I). These zones are within a sequence of Cretaceous volcanic and sedimentary rocks striking 015 degree s and dipping 45 degrees west. Feasibility ore reserves were 28 million tonnes grading 106 g A g/t, 0.96 g Au !t and 0.38% Cu a strip ratio of 2.2 to I. A detailed mineralogical description has been presented and a comparison of the two ore zones is shown in Table I."

Jan 1, 1986

By C. J. Rockingham

"A comparative study of sulphide textures has been carried out on samples from four Archean copper-zinc massive base metal sulphide deposits: Kidd Creek, Ontario; Lake Dufault -Norbec, Quebec; Hood River-41, N. W. T.; and Geco, Ontario. These deposits have undergone metamorphic recrystallization under a range of conditions, and results of this study indicate that certain sulphide textures may be used as qualitative indicators of metamorphic grade, whereas other cannot.The sulphide textures of most value in this regard are sulphide grain sizes, which increase with increasing metamorphic grade, and the presence or absence of sedimentary/diagenetic textures, which are destroyed at the lower amphibolite facies of metamorphism. Chalcopyrite and pyrrhotite intergrowths in sphalerite increase in size, in degree of coalescence and in the ratio of unmixed pyrrhotite to chalcopyrite inclusions with increasing metamorphic rank. With increased metamorphic grade, the pyrrhotite intergrowths change from rounded inclusions on grain boundaries to rod-like shapes along sphalerite twin planes. There is also a general increase in the relative proportion of pyrrhotite in the deposits. Textures that appear to have little value as indicators of metamorphic grade are sulphide deformation textures, and triple junction point angles and their standard deviations, which show little variation from the lower greenschist to the upper amphibolite facies of metamorphism. The presence or absence of myrmekite-like magnetite also has little value in determining the relative metamorphic history of these deposits, as it is a product of local contact metamorphism."

Jan 1, 1980

By R. S. Nichols

"During 1973 to 1978, Canadaka Mines Limited, a subsidiary of St. Joseph Explorations Ltd., undertook an extensive exploration and development program in the Cobalt area. This program resulted in the delineation of previously unknown stratigraphic units in the Archean volcanic sequence. During this time period, significant are controls related to area silver deposits were also identified.The Archean geology is comprised of a volcanic pile conformably overlain by sediments. The volcanics contain at least two felsic volcanic centres near the stratigraphic top of the pile. The bulk of the pile consists of mafic flows and interflow sediments. lnterflow sediments around silver are shoots contain mineralized halos of base metal sulphides. The halos exhibit lateral and vertical metal zoning with Cu, Pb and Zn mineralization decreasing away from an are shoot.Silver mineralization controls determined during the Canadaka program agree with the historically well established importance of Coleman sediments as well as Archean contacts for hosting silver deposits. The vertical extent of are shoots is typically 150to 250ft. A strong correlation was found to exist in the Cobalt area between Archean strike and the strike of are veins. Finally, al/ Cobalt area are deposits appear to be associated with a distinct volcanic pile at the top of a sequence of Archean flows."

Jan 1, 1988

By M. R. Henzinger, G. Lenz, A. Gaich, Pötsch, W. Schubert, P. Wagner

"The better the information on the rock mass and its fracture system, the better is the basis for any rock mechanical decision that is required during the excavation process. While in conventional tunnelling free view to the tunnel face is available, possibilities are limited for mechanised tunnelling using a tunnel boring machine (TBM). An approach, already formulated in 2005, is used that produces digital photographs through openings in the cutting wheel of a TBM and merges them into a circular three-dimensional image. The 3D image is then used for geometric rock mass characterisation purposes including geological mapping, for example to measure spatial orientations or determine joint spacing. In the paper the basic concept is described together with first results from a pilot test.INTRODUCTIONA three-dimensional image unites digital photographs with spatial information on the objects/surfaces it shows. Since they combine geometric and visual information they are a straightforward source for geometric rock mass analysis and geological mapping. Their obvious benefits among others are: (i) they allow spatial measurements even in inaccessible regions, (ii) they provide objective and reproducible records of the rock mass conditions, and (iii) they increase working safety (Gaich et al. 2004).Pre-requisite for the generation of 3D images is the acquisition of at least two photographs from the region of interest. From the photographs the imaged object surfaces are reconstructed by means of image analysis using methods from photogrammetry (Slama, 1980) and computer vision (Hartley & Zisserman, 2001). See also Figure 1."

Jan 1, 2015