Дисертації з теми "Orebody"
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1
Banda, Sraj Umar. "Caving mechanisms for a non-daylighting orebody." Doctoral thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63994.
Повний текст джерелаАнотація:
The sublevel caving mining method is a mass production method with potentially very low operational costs. The success of this method is dependent on, among other factors, the cavability of the orebody and the overlying rock mass. However, caving of the surrounding rock mass also results in deformations in the cap rock as well as on the ground surface above the orebody being mined. From this follows that any existing infrastructure on the ground surface must be relocated as not to be affected by the mining-induced deformations.This thesis work was undertaken to bring about a better understanding of the rock mass behavior in the cap rock of non-daylighting orebodies, with particular application to the Printzsköld orebody as part of the LKAB Malmberget Mine. Rock testing, field observations and underground mapping was conducted to characterize the rock mass in the caving environment. A methodology for identifying the caving front based on seismic monitoring data was derived by studying the Fabian orebody (which has caved to surface), and using laser scanning data for validation. The methodology was then applied to the Printzsköld orebody to identify the caving front.Numerical modeling was performed for various scenarios of the rock mass as mining proceeded. Modeling included (i) stress analysis to understand stress changes and their effects on the rock mass behavior, (ii) discontinuum numerical modeling to quantify the influence of large-scale geological structures on the cave progression, and (iii) discontinuum cave modeling to simulate possible cave mechanisms in the cap rock more explicitly. Laser scanning together with seismic event data were used to calibrate the numerical models.The numerical simulation results showed that as mining progresses, the cap rock and hangingwall were exposed to stress changes that resulted in yielding. Two failure mechanisms were predominantly at play (i) shear failure (dominant in the cap rock) and (ii) tensile failure (dominant in the hangingwall). The presence of the large-scale structures affected thenearfield stresses through slip along the cave boundaries. The effect of the structures on the far field stresses were less significant.Discontinuum modeling to explicitly simulate failure and caving involved simulating the rock mass as a jointed medium using Voronoi tessellations in 2D, and bonded block modeling (BBM) in 3D. Both the 2D and the 3D modeling results showed fair agreement when comparing the inferred boundary of the seismogenic zone, with that identified from seismic monitoring data. Predictive numerical modeling was conducted for future planned mining to assess future cave development in the cap rock. The results from 3D modeling indicated that cave breakthrough for the Printzsköld orebody is expected when mining the 1023 m level, corresponding to approximately year 2022, as per current mining plans. The 2D model was non-conservative with cave breakthrough predicted to occur when mining the 1109 m level, corresponding to the year 2028.The estimated boundary between the seismogenic and yielded zones, as defined in the Duplancic and Brady conceptual model of caving, was coinciding with, or was close to, the cave boundary in the Printzsköld orebody. This may imply that in some areas the yielded zone was not present and that the Duplancic and Brady model may not be universally applicable. Additional work is required to verify this indication, as well as to fine-tune the modeling methodology.
2
Francis, Helen. "Orebody complexity in geological control over selective mining." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/MQ44008.pdf.
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3
Francis, Helen. "Orebody complexity in geological control over selective mining." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20204.
Повний текст джерелаАнотація:
This thesis proposes a morphological complexity index for use in classifying orebodies. Formulated and tailored for application on underground steep clipping narrow base metal orebodies from Inco Limited's Manitoba Division, the complexity index was proved transferable to the base metal deposits of Inco Limited's Ontario Division. Thus it appears that the index could be applied to various styles of mineralization and orebody morphology.The complexity classification was designed to aid in geologic control and subsequently improve mining method performance. Motivated by an industry wide move from selective mining to bulk mining, to increase productivity and improve safety. It is intended that development and application of an orebody complexity index will increase the understanding of geology and prevent the sacrifice of selectivity, minimizing dilution and ore loss. With the advent of automation, simplification in mining is necessary and thus more intelligent design and control vital. This thesis offers one means by which MDPPC (Mine Design, Planning and Production Control) could be further integrated with geological understanding to achieve such an end.
The thesis provides explanation of how such a complexity index can be used to understand mining method performance and be used for more successful mine design.
4
Llana-Rodriguez, A. H. "Orebody modelling and open pit optimization using exploration data." Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355441.
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5
Yavuz, Sinem. "Seismic characterization of Volcanogenic massive sulfides – the Semblana orebody, Portugal." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/48.
Повний текст джерелаАнотація:
The exploration at Neves Corvo was further progressed through specialised elastic property measurements and PRA processing. Unambiguous imaging of the known VMS deposit was achieved through pre-stack imaging, followed by the calibration of seismic data with sonic and pseudo logs, which was an integral part of the volumetric interpretation. Quantitative interpretation of the Semblana deposit’s was performed with acoustic and elastic impedance inversion and AVO analysis, which demonstrated the unique nature of massive sulfide response.
6
Moses, Mokete. "The deportment of manganese in the Gamsberg East orebody South Africa." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/53531.
Повний текст джерелаАнотація:
The Gamsberg East orebody is the least studied orebody of the Gamsberg zinc (Zn) deposit. The Gamsberg Zn deposit is a largest undeveloped Broken Hill-type deposit, which is well known for relatively low zinc grade as well as manganese (Mn) being a problem and penalty element. The occurrence of manganese within the sphalerite crystal lattice is one of the reasons for the lack of mining development over the past three decades. The recent metallurgical test works of the Gamsberg East ore showed that alabandite floats faster than sphalerite and this adds to the Mn penalty factor. Alabandite (MnS) was first reported as trace concentrations, but it was most recently found in anomalous concentrations in the Gamsberg East orebody. Up to 16 %wt alabandite occurs within the pelitic schist of the Gams Formation, and concentrations below 2 %wt occur within the top half of meta-pelite ore. The occurrence of alabandite is also associated with thicker or well developed portions of the ore horizon, which is also associated with manganese enrichment. The model of formation for alabandite is similar to that of sphalerite and Fe-sulphides during metal-sulphide formation in the Gamsberg Zn deposit. Alabandite is therefore pre-metamorphic and its formation is controlled by change in redox water conditions from chemogenic to detrital facies, sulphur fugacity, change in pH and hydrothermal fluids with temperature less than 300 °C, rich in manganese and iron but poor in zinc. Manganese is also hosted in silicate and oxide minerals, such as by pyrophanite, jacobsite, franklinite, amphiboles, micas, pyroxenes/pyroxenoids, and garnets.Dissertation (MSc)--University of Pretoria, 2015.
Geology
MSc
Unrestricted
7
Lood, Stark Gustav. "A process mineralogy study of grinding characteristics for the polymetallic orebody, Lappberget Garpenberg." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86988.
Повний текст джерелаАнотація:
Most of the high-grade ores have been depleted globally, thus the effective processing of the low-grade and complex ores require a comprehensive mineral characterization through the process mineralogy/ geometallurgical approaches. 30-70 % of the total energy consumption in mining comes from the comminution step in mineral processing. This study, is aimed to investigate how different mineral domains in Lappberget, Garpenberg affect the grinding energy and throughput of an autogenous grinding mill (AG) and how blending different mineralogical domains will have an effect on throughput. The results were obtained through automated mineralogy using a Zeiss Sigma 300 VP at the QANTMIN scanning electron microscope (SEM) laboratory (Luleå University of Technology) and an in-house grindability test developed by Boliden Mineral AB. There is approximately a multiple of three times differences in the amount of energy consumption and throughput between the hardest and softest mineralogical domains. This difference is attributed to mineral composition of the individual domains and mineral characteristics. Blending different samples indicate that a higher throughput can be achieved and one possible hypothesis is that the harder minerals act as grinding media.
8
McKeown, Daniel J. "The lithology, structure and genesis of the Iron Duchess orebody, Middleback Ranges, South Australia /." Title page, table of contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09S.B/09s.bm157.pdf.
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9
Blakeman, Robert James. "The compositions and routes of the fluids generating the Navan giant base-metal orebody." Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392450.
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10
Hoffmann, Dennis. "Aspects of the geology, geochemistry and metamorphism of the lower orebody, Broken Hill deposit, Aggeneys." Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/22396.
Повний текст джерелаАнотація:
The Broken Hill deposit, Aggeneys, is a metamorphosed stratiform Cu-Pb-Zn-Ag sulphide deposit situated in the mid-Proterozoic supracrustal sequence of the Bushmanland Subprovince in the Namaqualand Metamorphic Complex. The deposit comprises two superposed orebodies, each consisting mainly of massive sulphide lenses and iron formation which are hosted within a metapelitic schist close to major quartzite horizons. This study is concerned with the tectonically lower orebody (LOB). The iron formation is magnetite-rich and contains varying proportions of (Fe,Mn)-rich silicates (garnet, amphibole, olivine, orthopyroxene, pyroxenoid), quartz and Cu-Pb-Zn-sulphides. These minerals occur in mm- to 5 cm-thick bands and are often traceable over tens of metres. The well preserved banding is considered to represent bedding. Five different varieties of silicate-rich mesobands in the iron formation can be distinguished based on the predominant mineral assemblage: (a) amphibole-olivine-quartz +/- garnet, (b) amphibole-quartz, (c) garnet-apatite-quartz +/- amphibole, (d) garnet-apatite-quartzorthopyroxene, (e) pyroxferroite-quartz +/- amphibole and (f) quartz. These rocks all contain magnetite, and Ba-rich biotite is common but is not always present.
11
Gray, Matthew Dean 1933. "Gold mineralization in the Black Cloud #3 carbonate replacement orebody, Leadville Mining District, Lake County, Colorado." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/558083.
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12
Gustin, Mae Sexauer. "A PETROGRAPHIC, GEOCHEMICAL AND STABLE ISOTOPE STUDY OF THE UNITED VERDE OREBODY AND ITS ASSOCIATED ALTERATION, JEROME, ARIZONA." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/187546.
Повний текст джерелаАнотація:
The United Verde orebody, a Proterozoic volcanogenic massive sulfide deposit, is hosted by the Cleopatra Formation. The Cleopatra Formation is subdivided into two distinct members, the Upper and Lower, on the basis of alteration facies, whole rock geochemistry and the chemistry of alteration minerals. The Lower member was deposited prior to ore deposition and consists of five major alteration facies. Facies Bl, the most distant from the orebody represents the recharge area for the ore-forming fluid. Facies B2 surrounds the major discharge area or the chlorite pipe. These three facies contain chlorite and quartz as alteration minerals in variable amounts. Two facies, 81 and S2, contain quartz and sericite as alteration minerals. Mass balance calculations show progressive removal of Na and Ca, and addition of MgO and FeO* from the area of recharge (facies Bl) to facies B2 to the chlorite pipe. Whole rock δ¹⁸O values are high relative to least altered Cleopatra Formation in the recharge area and low in the discharge zone. Mineralogy and geochemistry of samples from the Upper member indicate that it was deposited following ore deposition and interacted with fluids rich in silica and iron. The hydrothermal fluid, which is interpreted to have been seawater, evolved to a high temperature slightly acidic, reduced fluid during water-rock interaction(log a₀₂ = -33 to -41; log a(H2S) = -2.6 to -5.0). The fluid δ¹⁸O and δ¹³C₀₂ values increased. Calculated δ¹³C₀₂ and δ¹⁸O fluid values, and sphalerite and chlorite chemistry imply that mixing of the hydrothermal fluid with seawater occurred in the orebody. the upper The levels of the chlorite pipe and in limited range in δ³⁴S values of sulfides is consistent with the derivation of the oreforming fluids from the reduced basal layer of a stratified basin. The study area represents only a small part of the United Verde circulation cell. Increased δ¹⁸O values of the fluid, and the need for a source of Mg, Fe and other metals suggest that the fluids may have circulated into the Shea Basalt.
13
Rickard, Jason H. "Petrological and mineralogical study of Cu-Ni-PGE-bearing ores within the 100 orebody, Copper Cliff North mine, Sudbury, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0012/MQ52404.pdf.
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14
Ford, Colin Victor. "The integration of petrologic and isotopic data from the Boulder Conglomerate to determine the age of the Navan orebody, Ireland." Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/1134/.
Повний текст джерелаАнотація:
The Boulder Conglomerate is the Lower Carboniferous sedimentary allochthon deposited in the second order half graben created by major listric normal faults in the Navan area. The base of the Boulder Conglomerate comprises erosive-based, highly immature rock avalanches which are interbedded with hemipelagic limestone. Sulphide mineralisation in the autochthon, the Pale Beds Ore, is truncated by the fault-generated unconformity and is reworked as clasts and matrix into the basal Boulder Conglomerate. Matrix-deficient breccia beds deposited on the unconformity possess mineralisation as cement to interclast porosity. This cement is contiguous with replacement and fracture-cementing mineralisation in limestone strata beneath the unconformity. Mineralisation associated within the interbeds to the Boulder Conglomerate occurs as early diagenetic concretions and as stratiform replacement. The 34S of these sulphides ranges from -21‰ to +1‰. The rock avalanches are overlain by clast-bearing carbonate mud strata. The carbonate mud is replaced by pyrite and paragenetically later sphalerite and galena. The isotopic range of 34S for pyrite (-32‰ to -35‰) is distinct from that of the zinc and lead sulphides (-18‰ to +6‰). The uppermost Boulder Conglomerate is characterised by slumped and brecciated mineralisation which is dominated by pyrite. The 34S values of the in situ and reworked mineralisation range from -40‰ to -23‰. The Thinly Bedded Unit overlies the Boulder Conglomerate and comprises interlayered shales and calcarenite and laterally impersistent, erosive-based, graded bioclastic and oolitic microbeccias. Mineralisation occurs as selective replacement to the microbreccia and as stratiform sphalerite and pyrite mud. The latter occur in-situ as laminae and as channelised debris flows. The reworked sulphide mud supports plant fragments which exhibit exceptional preservation by pyrite, sphalerite and galena. The 34S of the laminated and reworked sulphides ranges from -37‰ to -41‰. (DXN008,313)
15
Rickard, Jason H. Carleton University Dissertation Earth Sciences. "Petrological and mineralogical study of Cu-Ni-PGE-bearing ores within the 100 orebody, Copper Cliff North mine, Sudbury, Ontario." Ottawa, 2000.
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16
Tipe, Luis Alberto Martinez. "Strategic project evaluation for open pit mining ventures using real options and allied econometric techniques." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/48334/1/Luis_Martinez_Thesis.pdf.
Повний текст джерелаАнотація:
Open pit mine operations are complex businesses that demand a constant assessment of risk. This is because the value of a mine project is typically influenced by many underlying economic and physical uncertainties, such as metal prices, metal grades, costs, schedules, quantities, and environmental issues, among others, which are not known with much certainty at the beginning of the project. Hence, mining projects present a considerable challenge to those involved in associated investment decisions, such as the owners of the mine and other stakeholders.
In general terms, when an option exists to acquire a new or operating mining project, , the owners and stock holders of the mine project need to know the value of the mining project, which is the fundamental criterion for making final decisions about going ahead with the venture capital. However, obtaining the mine project’s value is not an easy task. The reason for this is that sophisticated valuation and mine optimisation techniques, which combine advanced theories in geostatistics, statistics, engineering, economics and finance, among others, need to be used by the mine analyst or mine planner in order to assess and quantify the existing uncertainty and, consequently, the risk involved in the project investment.
Furthermore, current valuation and mine optimisation techniques do not complement each other. That is valuation techniques based on real options (RO) analysis assume an expected (constant) metal grade and ore tonnage during a specified period, while mine optimisation (MO) techniques assume expected (constant) metal prices and mining costs. These assumptions are not totally correct since both sources of uncertainty—that of the orebody (metal grade and reserves of mineral), and that about the future behaviour of metal prices and mining costs—are the ones that have great impact on the value of any mining project.
Consequently, the key objective of this thesis is twofold. The first objective consists of analysing and understanding the main sources of uncertainty in an open pit mining project, such as the orebody (in situ metal grade), mining costs and metal price uncertainties, and their effect on the final project value. The second objective consists of breaking down the wall of isolation between economic valuation and mine optimisation techniques in order to generate a novel open pit mine evaluation framework called the ―Integrated Valuation / Optimisation Framework (IVOF)‖. One important characteristic of this new framework is that it incorporates the RO and MO valuation techniques into a single integrated process that quantifies and describes uncertainty and risk in a mine project evaluation process, giving a more realistic estimate of the project’s value. To achieve this, novel and advanced engineering and econometric methods are used to integrate financial and geological uncertainty into dynamic risk forecasting measures.
The proposed mine valuation/optimisation technique is then applied to a real gold disseminated open pit mine deposit to estimate its value in the face of orebody, mining costs and metal price uncertainties.
17
Rasmeni, Sonwabile. "Lithostratigraphic correlation, mineralogy and geochemistry of the lower manganese orebody at the Kalagadi Manganese Mine in the Northern Cape Province of South Africa." Thesis, University of Fort Hare, 2012. http://hdl.handle.net/10353/d1016155.
Повний текст джерелаАнотація:
The Kalagadi Manganese mine in the Kuruman area of the Northern Cape Province of South Africa contains reserves of Mn ore in excess of 100Mt. Mineralization in the mine lease area is restricted within the Hotazel Formation of the Voȅlwater Subgroup, belonging to the Postmasburg Group, the upper subdivision of the Transvaal Supergroup. Surface topography is characterized by flat lying, undulation with minimal faulting and the ore are slightly metarmophosed. This study investigates the general geology of the mine, lithostratigraphic subdivision and correlation of the economic Lower Manganese Orebody (LMO) of the Kalagadi Manganese Mine in order to guide mining plan and operations once the mine is fully commissioned. At the commencement of this study, Kalagadi Manganese mine was a project under exploration with no specific geology of the mine lease area and no lithostratigraphic subdivision. The study also aimed determining the extent of lithostratigraphic correlation between the LMO economic orebodies of the Kalagadi Manganese mine with that of underground Gloria and open-pit Mamatwan mines. Four methods including petrographic microscope, Scanning electron Microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were applied mainly for the mineral identification, chemical composition and ore characterization of the Lower Manganese Orebody (LMO) at Kalagadi Manganese mine. The results of this study indicates the following: (1) Eleven textural distinct zones with economic zones restricted to the middle while the lower grade zones are confined to the top and bottom of the LMO; (2) The economic zones, comprising of Y, M, C and N subzones attain an average thickness of 10 m and are graded at an average of 40% Mn while the Mn/Fe ratio varies from 6 to 9; (3) The most economic zones are M and N subzones which are mostly characterized by oxidized ovoids and laminae, a characteristic applicable even to other zones of economic interest; (4) Braunite is the main mineral of the manganese ore and is often integrown with kutnahorite and other minerals (hematite, hausmannite, Mg-calcite, calcite, jacobsite, serpentine and garnet) which are present in variable amounts; (5) The Mg-rich calcite (Ca, Mg)CO3 is the second dominant manganese carbonate mineral and it corresponds to elevated MgO concentration and is often associated with marine environment. The occurrence of the Mgcalcite is not common in the manganese ore of this area except for the Mn-calcite, which was not determined by XRD analyses in this study; (6) MnO is the most abundant major oxide in the manganese ore while other major oxides present in decreasing order of abundance are CaO, SiO2, Fe2O3, and MgO. The oxides TiO2, Na2O, K2O, Al2O3, and Cr2O3 are depleted and are mostly 0.01wt% and 0.001wt% respectively while P2O5 concentrations are low ranging from 0.02wt% to 0.3wt%. The trace element concentrations of Ba, Zn and Sr in most borehole samples are slightly elevated ranging from 100ppm to 3.9% (36000pm) while Co, Cu, Ni, Y, As, Zr, V and La rarely exceed 50ppm. The enrichments of Cu, Zn, Ni, Co and V that are commonly associated with volcanogenic hydrothermal input in chemicals may reach up to 70ppm; (7) The mineralogical and geochemical characteristics of the manganese ore in the Kalagadi Manganese mine lease area are similar to that of Low-Grade Mamatwan-Type ore. The cyclicity (Banded Iron Formation ↔ Hematite lutite ↔ braunite lutite) and alternation of manganese and iron formation have been confirmed; and (8) The oxygen δ18O isotope values (18‰ to 22‰) indicate a slight influence of metamorphism of the manganese ore. No positive correlation exists between δ13C vs δ18O values and Mn vs δ13C values. Such observations indicate minimal action of organic carbon during manganese precipitation where the organic matter was oxidized and manganese content reduced. On the other hand, the manganese carbonates (CaO) are positively correlated with carbon isotope, this indicates diagenetic alteration and the involvement of biogenic carbonate during the formation of manganese carbonates. It is concluded that the lithostratigraphic subdivision at Kalagadi Manganese mine is best correlated physically, mineralogically and geochemically with that of Gloria mine operating in the Low Grade Mamatwan - Type ore while correlation with an open-pit Mamatwan mine is also valid.
18
Rentzelos, Theofanis. "Numerical Investigation of Rock Support Arches." Thesis, Luleå tekniska universitet, Geoteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76698.
Повний текст джерелаАнотація:
The Garpenberg mine, owned by the Boliden Mining group, has established a trial area at Dammsjön orebody in order to examine the possibility of increasing the productivity of the mine. The mine uses the rill mining method with a current rill height of 15 m. In order to increase the productivity, the mine is examining the possibility of increasing the height of the rill. The trial area is located at 882 m depth surrounded by dolomite on the hangingwall and quartzitic rock on the footwall side. Rock support arches have been installed, in addition to the regular support pattern, to test their effectiveness on stabilizing the ground around the drifts. The arches have been installed in every 6 m and every 3 m in different parts of the test area. Rock samples from the trial area were brought to the university laboratory for testing. The data gathered from the laboratory tests along with the data from the monitoring of the trial area were used to develop a calibrated numerical model. A three-dimensional (3-D) model was therefore created, by using the FLAC3D numerical code. After the calibration of the model a parametric study was conducted for different rill heights and different arch spacing to investigate the performance of the arches. Specifically, the case of no arch installation along with the cases of an installed arch every 6 m and 3 m were tested, for the rill heights of 15 m, 20 m, 25 m and 30 m. The study concluded that the arches assisted in reducing the ground convergence in the production drift. The results also showed that the total height of the rill bench yields regardless of its height. After the yielding, the rockmass can no longer support itself and caves under its own weight. The larger the rill height, the larger the volume of loose rock that has to be supported and thus, higher the convergence. Furthermore, it was also observed that, significant amount of convergence in the production drift occurred during the drifting of the top drive and less during the stoping of the rill bench. This indicates that, the timely installation of the arches is an important criterion for their performance.
19
Lotfolah, Hamedani Mohammad. "Orebody modelling for exploration: the western mineralisation, Broken Hill." Thesis, 2011. http://hdl.handle.net/2440/67195.
Повний текст джерелаАнотація:
The Broken Hill Zn-Pb-Ag deposit (Australia) is the largest base metal deposit in the world (Large et al. 2005)1. Despite almost 130 years of mining, core logging is still undertaken qualitatively. Most old core has disappeared. The Western Mineralisation is the subject of this study and it is soon to be exploited in the Rasp Mine. The 77 Western Mineralisation drill cores provided an opportunity to statistically evaluate 3,215 surface and underground samples. In this process, 61,696 data were acquired from magnetic susceptibility measurements and quantitative mineralogical, lithological and textural core logging. These data sets were integrated with assay, specific gravity, collar and survey data. The large data sets2 (93,192) were treated by statistical methods such as univariate and bivariate analyses, compositional data analysis, statistical test, linear multivariate regression, cluster analysis, principal component analysis, variogram analysis and univariate ordinary kriging estimation. Moreover, the previous data set of mineral chemistry was evaluated by correspondence analysis, compositional data analysis and principal component analysis. The statistical results were demonstrated in variety of diagrams such as bar diagrams, core log diagrams, contour plots, correspondence map, map of PC loading and PC score, biplot, 3D biplot and 424 cross-sections of the orebody. It was shown that Bi and Sb are pathfinder elements for the Western Mineralisation and that these elements form a broader halo around sulphide masses whereas Ag, As and Cd form a small halo. Galena-sphalerite rich ores have a higher proportion of magnetic pyrrhotite and magnetic susceptibility can be used to evaluate proximity to sulphide masses. Statistical studies suggest that Broken Hill might not be an isolated deposit and that the "next" Broken Hill may not be identical. Predictor elements for Pb are Fe, Ag and Bi and for Zn are Cd, Sb and Ag. Optimal sampling is on 22m and 10m along and across strike respectively and a 20 × 20 × 10 m polygon is the optimum size for block model analysis. The Western Mineralisation at Broken Hill is zoned from a Pb-Zn-S-Cd rich upper portion to a Cu-Ag-As-Bi rich lower portion. Variations within the Western Mineralisation may be primary features but are more likely to derive from intense tectonism.
1 Harvard (UTS) Style - 6th edition (version 2004) has been used for the purpose of citation and referencing. Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
20
Finch, Adrian Patrick. "A Geostatistical study of the copper orebody within the Phalaborwa complex." Thesis, 2015. http://hdl.handle.net/10539/17255.
Повний текст джерелаАнотація:
This Report makes a geo-statistics comparison between
Benches 10 and 20 of the Palaborwa open pit and presents
a suite of geo-statistics programmes developed for the
Sinclair Spectrum personal computer.
It has always been assumed for planning and grade
control purposes, that values in one bench can be
extrapolated into the bench below and this is an attempt
to validate the assumption.
Assays are done on drill chip samples from every
blastnole drilled in copper bearing composites; the
values are then recorded by position on 1:500 scale
Bench Plans. These data are regularised by averaging
values within 10m x 10m blocks which are then used in
the geo-statistics analysis. A three parameter
lognormal model was used to represent the distribution;
the two benches were compared with each other in the
analysis through to Kriging of each central area.
Although the benches were found not to have the same
distribution there is a high degree of similarity and
the use of geo-statistics would improve the accuracy of
grade predictions.
21
Loidl, Gernot C. "The Elura Orebody: a multidisciplinary study investigating geochemical mineralogical & geometallurgical ore characteristics." Thesis, 2012. http://hdl.handle.net/2440/82375.
Повний текст джерелаАнотація:
The Elura Zn-Pb-Ag deposit 43km NNW of Cobar, NSW, contained a pre-mining resource of 50.7 Mt at 8.8 wt% Zn, 5.6 wt% Pb, 107 g/t Ag and 0.2 wt% Cu. Sediment-hosted ore within a turbiditic sequence is strongly structural controlled. It is sheet-like with several elongated, subvertical massive zoned sulphide bodies with central pyrrhotitic cores surrounded by pyrite ore which is enclosed by semi-massive and breccia-stringer mineralisation. This study showed pronounced grain sizes, texture, mineral composition and trace element geochemistry heterogeneity. The pyrite-pyrrhotite-galena-sphalerite ore has minor marcasite, chalcopyrite and arsenopyrite and trace tetrahedrite (±freibergite), native silver and magnetite. Enrichment trends towards the surface and peripheral pyrite-dominated ore zones are in Ag, As, Tl, Hg, Sb, Sn, Mo and Au. The first Re-Os whole rock massive sulphide isochron age is 378±15 Ma. Initial ϒOs of ~170 is either caused by juvenile continental crust of the Lachlan Fold Belt as metal source or by a contribution of primitive mantle Os. Zinc isotope compositions of sphalerite (δ⁶⁶ZnJMC 0.220- 0.450‰) suggest effectively leached average continental crust as the source for metals, chlorite thermometry showed temperatures at 314-343°C, high Cu concentrations coincide with light Zn isotopes that define two major zones of fluid influx and the isocon method showed host lithology replacement was negligible during ore genesis. Sulphides formed in sites of increased dilation and fracture-induced permeability during prolonged periods of fracturing and fluid pulses. Decreasing fluid pressure and adiabatic cooling initiated precipitation of sulphides. No evidence for fluid mixing was identified. Initially, lower parts of the orebody formed in dilational zones in sandstone-rich sequences along a transpressional fault corridor. Major fracturing then caused the formation of upper main lode and upgrading of the lower main lode ore zones. Changing fluid temperatures, internal refinement via dissolution-reprecipitation and temporal fluid composition change created vertical mineralogical and geochemical ore zonation. The orebody was modified during post-depositional compression during continued basin inversion resulting in sulphide remobilisation, upgrading and amplified ore zonation. Zinc and, in particular, Pb recovery rates significantly fluctuated since production began in1983. Fluctuating recovery rates resulted from grain size variability and subsequent poor particle liberation during grinding. Silver recoveries rarely exceeded 50%. Poor Ag recoveries were due to fine-grained argentian tetrahedrite, common associations with gangue phases and alteration of tetrahedrite. High concentrations of Bi were encountered recently in lead concentrate. A galenamatildite solid solution contains Bi (max. 5,645ppm). High Bi is limited to the lower most main lode ore zone. Geometallurgical ore characterisation via QEMSCAN® was undertaken to predict mineral processing characteristics of ore sourced from parts of the same stope. On the stope scale there are significant variations in flotation characteristics from different parts of the stope which enables prediction of recoveries, concentrate qualities and mill throughput. Theoretical recovery calculations suggest that ore from the western part will have10% lower recovery. Theoretical and long-term average recoveries are similar for Zn but not for Pb. Theoretical data may over- estimate recovery because sample preparation may liberate more particles than plant grinding. An overview of mineralogy and trace elements allows geometallurgical ore characterisation on the stope scale to better predict mill performance. Investigation of geometallurgical ore characteristics and penalty element concentrations are recommended on a stope-by-stope basis within life-of-mine planning.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
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Kaviua, Sheron Tjiuavioye. "Geostatistical evaluation of the eastern ore field one (EF1) orebody, Rosh Pinah zinc mine, Namibia." Thesis, 2018. https://hdl.handle.net/10539/25723.
Повний текст джерелаАнотація:
A Dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering.
16 May 2018 in JohannesburgThe geometry, size and quality of a deposit are key parameters required for decision-making regarding mining methods, capital investments or divestments, economic viability and processing methods. The dissertation uses a quantitative approach to assess three geological modelling methods for orebody geometry. It applies Principal Components Analysis (PCA) in order to understand the variability and correlation in the data. The dissertation aims to determine the significance of increasing the composite size to 3 m for grade estimation and to estimate the tonnes and grades of the Eastern Ore Field 1 in-situ resource as on 31 December 2016. A MineSight, a Leapfrog and a hybrid of MineSight and Leapfrog modelling method were assessed, aiming to reduce the modelling time. The Minesight and Leapfrog hybrid model is recommended for modelling complex sedimentary exhalative deposits. The PCA was carried out using Matlab. Based on the correlation of 0.998, the first principal component increases with increasing Ag, Zn and Pb and it correlates most strongly with Ag. The second principal component increases with Zn, with a correlation of 0.985. With a correlation of 0.927, the third component increases with Mg. A 3 m composite size is recommended for estimating EF1 because the generated block-model estimates have lower means, standard deviations, variances and numbers of extreme outliers. The 3 m composite size is closer to the SMU at Rosh Pinah, and produces a better block estimate than 1.5 m composites, the later gives more tonnes and higher grade due to the volume-variance effect, which ultimately leads to overestimation of the mineral deposit. The total in-situ EF1 resource estimated using the Ordinary Kriging interpolation method as on 31 December 2016 was 814,100 tonnes at 8.58% Zn, 3.19% Pb and 79.22 ppm Ag.
MT 2018
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Stewart, Peter William. "Geology, geochemistry, geochronology and genesis of granitoid clasts in breccia-conglomerates, MacLean extension orebody, Buchans, Newfoundland /." 1985. http://collections.mun.ca/u?/theses,119284.
Повний текст джерела
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Chanderman, Lisa. "Application of stochastic orebody simulation techniques to assess geological volume and grade uncertainty for gold reef deposits." Thesis, 2017. http://hdl.handle.net/10539/23453.
Повний текст джерелаАнотація:
A Dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirements for the Degree of Masters in Engineering by research only and to the Stochastic Mine Planning Laboratory, McGill University as part of the COSMO scholarship in Mine Planning under uncertainty
Johannesburg, 2017This dissertation discusses the use of stochastic orebody modelling techniques for assessing geological uncertainty associated with gold mineralisation at Geita Gold Mine in Tanzania, and proposes a practical methodology that can be applied to similar studies. As part of the pre-feasibility stage studies for underground mining at Geita, stochastic simulations were required to assess the geological uncertainty associated with isolating (modelled) high grade lenses that occur within the known low grade mineralisation currently targeted for underground mining. Two different simulation techniques are applied in this research: Sequential Indicator Simulation to generate lithofacies realisations from which to assess ore category boundaries and shapes for use in quantifying volumetric uncertainty; and Direct Block Simulations to simulate gold grade realisations from which to assess grade uncertainty. This study identified potential upside and downside mine planning scenarios for volumes and total metal content from the ore category and grade simulations respectively. The findings of the results demonstrated that the high grade zones are much more broken up and discontinuous than the currently modelled high grade shape. The current business case uses a probabilistic high grade shape based on a single grade indicator and a probability choice of 50 percent as the threshold for high grade. The results of the study consider a simulation of possible outcomes based on the same threshold grade indicator and hence quantify the uncertainty or total geological risk. This geological risk may be introduced to mine designs, production schedules and NPV predictions The stochastic workflow developed can be applied to analogous deposit types to assess the risk related to geological uncertainty. The work includes a description of practical considerations to be accounted for when applying the techniques.
MT 2017
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Schwarz, M. A. "Mineralogy and distribution of talc associated with Cu Mineralisation: A study of talc alteration in the Northern 3500 Orebody, Mount Isa, Queensland." Thesis, 2004. http://hdl.handle.net/2440/113487.
Повний текст джерелаАнотація:
This item is only available electronically.Copper mineralisation within the Mount Isa Mines deposit is associated with variable talc alteration. An understanding of the mineralogy and distribution of talc alteration associated with the northern 3500 orebody is important for future mining processes and could potentially be used for exploration targets around the Mount Isa area. Mineralogical and geochemical investigations have shown one major type of talc mineralogy throughout the entire 3500 orebody. Variations in colour and texture are visible macroscopically and microscopically but there are no distinctive differences in mineralogy. The talc has minor iron (~4 wt% FeO), probably due to the moderate iron within the Mount Isa system. The same type of moderately Fe-rich talc is found within the 1100 oreobody (Waring, 1990), suggesting a similar style of talc alteration extends beyond the 3500 orebody. The distribution of talc is reliant on the fluid pathway. The altering fluids have used selected faults within the 3500 orebody as pathways. The NSFW fault which roughly defines the eastern limit of mineralisation in the 3500 orebody is typically a strong wide shear zone with talc fill and is recognised as being a possible pathway for the fluids. Talc is dominant on the footwall of the 3500 orebody from south of 6700mN and dominant on the hangingwall, north of 6700mN. Within the siliceous core where mineralisation is at its greatest concentrations, talc is only located within faults. Outside the siliceous core where copper mineralisation is lower, talc alteration is present within the rocks and varies in quantity. The talc alteration has occurred after the formation of dolomite and pyrite. However, the timing of the talc alteration in relation to the copper mineralisation remains unknown. Four methods of determining the most accurate and cost effective method for talc abundance estimates within the 3500 orebody are evaluated. The most effective method is through the calculation of stoichiometric equations from XRF assay data. These calculations can be used to create an accurate talc 3D numerical model that enables the distribution and numerical quantity of the talc to be viewed throughout the copper mine.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2004
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Johnson, Russell Douglas. "Orebody characterisation and structural features that govern copper and cobalt mineralisation in the eastern limb of the Lufilian Arc, Democratic Republic of Congo." Thesis, 2015. http://hdl.handle.net/10539/16918.
Повний текст джерелаАнотація:
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. August 2014.The Central African Copperbelt is located in the Lufilian Arc which straddles the border between Zambia and the Democratic Republic of Congo (DRC). Mineralisation of the cupriferous Arc is found in basal Neoproterozoic Katangan Supergroup sedimentary rocks, which in DRC are termed the Mines Series Subgroup. The Mines Series is divided into the dolomitic and carbonaceous GRAT, DStrat RSF, RSC, SD and CMN units. The composition of the units is homogeneous across the Lubumbashi district and potentially across the Katangan basin. This study focussed on the Kinsevere and Ruashi deposits in the Lubumbashi district, which are approximately 50 km apart. The study confirmed that relative eustatic sea level changes resulted in the non-deposition of the RSF and RSC stratigraphic units at Kinsevere. Sedimentation was followed by early pervasive potassic alteration and silicification at the diagenetic stage whilst a magnesian dolomitisation event resulted in alteration of potassic feldspars and recrystallisation of carbonates. Albitisation was veincontrolled and late-stage scapolitisation altered evaporitic nodules. Finally, haematisation by late iron-rich fluids circulating through the Roan Group strata resulted in oxidation of sulphides. The structural analysis of Kinsevere Central pit indicates E-W and N-S shortening whereas the Ruashi pit 1 deposit underwent NE-SW and N-S shortening. Initial shortening, associated with Kolwezian deformation (D1), resulted in the formation of NE-thrust folds and a primary set of joints. The Kolwezian deformation event (D2), reoriented the shortening direction from E-W to N-S, creating interference folds and possibly a second set of joints. The final phase in the structural evolution of the Kinsevere and Ruashi deposits was late-stage brittle deformation (faulting). Mineralisation was a multi-stage process. Disseminated chalcopyrite and carrollite were deposited from formation waters during diagenesis in a stable basin environment. Chalcopyrite, carrollite, chalcocite and bornite are predominantly located at the base of the DStrat, whereas chalcopyrite and pyrite dominate the stratigraphically higher portions of the deposits. Hypogene vein mineralisation began at the syn- to late- orogenic stage with carrollite and chalcopyrite in beddingparallel veins. Possible changes in the compression direction created the perpendicularly oriented veins that host chalcopyrite, carrollite, bornite, covellite, digenite and chalcocite. Finally a late stage of chalcopyrite and pyrite deposition occurred in and around the evaporites, indicating a strong correlation between mineralisation, evaporites and scapolitisation. iii Near-surface supergene alteration of hypogene sulphide ores, resulted in Cu-Co carbonates and oxides, such as malachite, azurite, cobaltiferous malachite, chrysocolla, kolwezite and sphaerocobaltite being deposited in vugs and pore spaces above the meteoric water line. Faulted and brecciated zones tend to have deeper supergene alteration. Between the sulphide facies at depth and the supergene oxide facies at surface is a transition zone which marks the depth to which oxidation has penetrated. Sulphur isotope analysis from the Kinsevere and Ruashi deposits suggests a sulphur contribution from a continental Red-Bed sedimentary source and from an evaporitic source.
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Sloane, Lomar. "Sublevel open stoping : design of the O640, L651 and N659 sub-level open stopes in the 3000 orebody of the Mount ISA copper mines, Queensland, Australia." Diss., 2011. http://hdl.handle.net/2263/26206.
Повний текст джерелаАнотація:
This dissertation will explore the process followed in the design of a sub-level open stope (SLOS) by using examples of actual stopes scheduled to be in production between August 2006 and February 2007. The main objective is to give the reader an understanding into sub-level open stoping and the design process followed. The objective here is to present a design methodology applicable to sublevel open stoping, but also to then bridge the gap between theory and practice by applying said methodology to an actual design example. The design examples used in this dissertation is based on the O640, L651 and N659 stopes in the 3000 Orebody of Xstrata Copper Operation’s Mount Isa Mine, located in North-West Queensland, Australia. The actual design reports as required by the mine are attached in Annexure 1 through 3. Given the similarities of the designs, only O640 will be analysed comprehensively within the main content of this report, with L651 and N659 discussed specifically insofar issues that were unique to these stopes. With the design of O640, all aspects or design considerations as stipulated in the design process were discussed and analysed so as to define the final stope shape. These design considerations include: - Faulting
- Grade Contours
- Existing Development
- Surrounding Fill masses
- Rock Mechanics
- Reserves and Scheduling
- Development and Drilling
- Production and Firing (Blasting)
- Ventilation
- Services
- Filling
- Economic Analysis
Dissertation (MEng)--University of Pretoria, 2011.
Mining Engineering
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