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You searched for subject:(Gold ores Namibia). Showing records 1 – 2 of 2 total matches.

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Rhodes University

1. Slabbert, W L. Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia.

Degree: Faculty of Science, Geology, 2014, Rhodes University

The Navachab Gold mine, an orogenic lode gold deposit, is located in the Karibib region of the Pan-African (ca. 550-500) Damara belt of central Namibia. Gold mineralisation is developed within the steeply NW dipping limb of the Karibib dome. Here, ore envelopes trend along three main orientations: a) trends shallowly towards the NE (the down plunge extent), b) trends sub-vertically in and along the down plunge extent and c) trends sub-horizontally across the down plunge extent. The down plunge extent represents the bulk of the gold mineralisation, hosting the only high grade ores mined at Navachab. As such, past work primarily focused on establishing the controls to the mineralisation observed here. The sub-vertical and sub–horizontal ore trends are seen as secondary, lower grade, being hosted in the footwall. By cutting pushbacks into the footwall, in an effort to regain access to high grade pit bottom, future gold production almost exclusively relies upon optimally mining these ores. This underlines the importance to investigate and outline the mineralising controls to the secondary ore trends. This study identified the following prevailing quartz vein sets developed within the footwall, set (1) dips shallowly towards the NE (conjugate vein set), (2) steeply towards the NW (bedding parallel veins) and (3) steeply towards the SE (S2 foliation parallel). The NW and SE dipping sets contain high average gold grades, occurring at an infrequent vein density. The NE dipping veins, as a result of occurrence density alone, was highlighted as the dominant gold hosting set. Veining occurred during the late stages of the NW-SE directed, sub-horizontal shortening (D2) event and is associated with top-to-the-NW thrusting and NW-verging folds. Re-Os molybdenite dating from auriferous quartz veins indicates mineralisation occurred at 525-520 Ma. As crustal shortening amplified the Karibib dome, flexural flow developed fractures along bedding planes, providing the control to bedding parallel veins (NW dipping). With continued crustal compression the dome later experienced fold lock up associated with reduced mean rock stress and sub-horizontal extension occurred along the steeply NW dipping limb. Horizontal extensional gashes sucked in fluids to form the shallowly NE dipping conjugate vein set. These features suggest the regional D2 strain as the first-order control to quartz vein development, down plunge and within the footwall ores. To further define the secondary ores, lithological and structural controls were evaluated on a more detailed local scale. With equal amounts of biotite schist and calc-silicate host rock (bulk of the footwall lithology) material analysed, the biotite schist units were found to contain a larger volume amount of quartz veins. The mineralisation incurred is also developed at higher average gold grades compared to that of the calc-silicates, demonstrating biotite schist having the optimal rheology for quartz vein emplacement. Normal faulting and thrusting occurs widespread, at all scale levels, across the…

Subjects/Keywords: Gold ores  – Namibia; Ore deposits  – Namibia

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Slabbert, W. L. (2014). Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia. (Thesis). Rhodes University. Retrieved from http://hdl.handle.net/10962/d1016364

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Slabbert, W L. “Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia.” 2014. Thesis, Rhodes University. Accessed June 26, 2019. http://hdl.handle.net/10962/d1016364.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Slabbert, W L. “Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia.” 2014. Web. 26 Jun 2019.

Vancouver:

Slabbert WL. Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia. [Internet] [Thesis]. Rhodes University; 2014. [cited 2019 Jun 26]. Available from: http://hdl.handle.net/10962/d1016364.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Slabbert WL. Ore distribution controls of the Navachab Gold Mine, Damara Belt, Karibib District, Namibia. [Thesis]. Rhodes University; 2014. Available from: http://hdl.handle.net/10962/d1016364

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Rhodes University

2. Whitfield, Derek. The genesis and controls of gold mineralization south of Rehoboth, Namibia.

Degree: MS, Faculty of Science, Geology, 1991, Rhodes University

Gold mineralization is hosted within gossanous quartz-haematite veins in volcano-sedimentary lithologies of the Klein Aub - Rehoboth basin of the Irumide Belt, Namibia. Mineralization and hydrothermal alteration are restricted to deformed lithologies particularly the metasediments. Lithological relationships, geochemistry and metallogenic characteristics of the Irumide Belt suggest an intra-continental rift setting. Copper mineralization is well known along the length of the belt, from Klein Aub in the southwest to Ghanzi in the northeast, whereas gold mineralization appears restricted to the Klein Aub Rehoboth basin. The gold is envisaged as having being leached initially from graben fill sequences during rift closure and basin dewatering. Location of the mineralization is strongly controlled by structure and lithological contact zones. Such zones are percieved as having acted as conduit zones for escaping mineralized fluids during basin closure and deformation. Apart from the lack of an effective mineralizing trap, all features consistent with the development of an ore deposit are present. The largest mineralization traps within the area studied are shear zones followed by lithological contact zones. The Mebi and Blanks gold mines are developed over large shear zones while the Swartmodder and Neuras gold mines are situated over mineralized lithological contacts. The Swartmodder copper mine yielded ore from a mineralized schist enclave within granite. Copper and gold occurrences are attributed to two contrasting styles of mineralization. Copper mineralization is suggested to have developed during initial rifting of the belt (ie. stratabound sedimentary exhalative type), while the gold and minor copper resulted from rift closure and basin dewatering. Although no economical orebody was realized during the course of this study a model is proposed for the development of mineralization within the Irumide basement lithologies as a working hypothesis for future exploration.

Subjects/Keywords: Gold ores  – Geology  – Namibia; Gold ores  – Geology  – Africa, Southern

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Whitfield, D. (1991). The genesis and controls of gold mineralization south of Rehoboth, Namibia. (Masters Thesis). Rhodes University. Retrieved from http://hdl.handle.net/10962/d1005560

Chicago Manual of Style (16th Edition):

Whitfield, Derek. “The genesis and controls of gold mineralization south of Rehoboth, Namibia.” 1991. Masters Thesis, Rhodes University. Accessed June 26, 2019. http://hdl.handle.net/10962/d1005560.

MLA Handbook (7th Edition):

Whitfield, Derek. “The genesis and controls of gold mineralization south of Rehoboth, Namibia.” 1991. Web. 26 Jun 2019.

Vancouver:

Whitfield D. The genesis and controls of gold mineralization south of Rehoboth, Namibia. [Internet] [Masters thesis]. Rhodes University; 1991. [cited 2019 Jun 26]. Available from: http://hdl.handle.net/10962/d1005560.

Council of Science Editors:

Whitfield D. The genesis and controls of gold mineralization south of Rehoboth, Namibia. [Masters Thesis]. Rhodes University; 1991. Available from: http://hdl.handle.net/10962/d1005560

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