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N'Chwaning II Mine

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Journal Article
Published: 01 October 2012
European Journal of Mineralogy (2012) 24 (6): 991–1004.
...Cristian Biagioni; Elena Bonaccorsi; Stefano Merlino; Danilo Bersani; Claudia Forte Abstract X-ray diffraction studies of “tobermorite 10 Å”, obtained through heating of the “anomalous” tobermorite 11 Å from N’Chwaning II mine (Kalahari Manganese Field, RSA), show the widespread structural disorder...
FIGURES
First thumbnail for: Thermal behaviour of tobermorite from <span class=...
Second thumbnail for: Thermal behaviour of tobermorite from <span class=...
Third thumbnail for: Thermal behaviour of tobermorite from <span class=...
Journal Article
Published: 01 October 2012
European Journal of Mineralogy (2012) 24 (6): 981–989.
... differ in their behaviour upon heating, which can be “normal” if they collapse to form a 9 Å phase or “anomalous” if they preserve their original basal spacing. The “anomalous” thermal behaviour of tobermorite 11 Å from N’Chwaning II mine (Kalahari Manganese Field, Republic of South Africa), which does...
FIGURES
First thumbnail for: Thermal behaviour of tobermorite from <span class=...
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Image
Bunch of lath-shaped crystals of oyelite. N’Chwaning II mine, Kalahari, South Africa. Scanning electron microscope secondary-electron image.
Published: 01 May 2019
Fig. 2 Bunch of lath-shaped crystals of oyelite. N’Chwaning II mine, Kalahari, South Africa. Scanning electron microscope secondary-electron image.
Journal Article
Published: 01 April 2015
Mineralogical Magazine (2015) 79 (2): 485–495.
... y Si 6– y )O 15+2 x – y ·5H 2 O. Its endmember compositions correspond to tobermorite Ca 5 Si 6 O 17 ·5H 2 O ( x = 1 and y = 0) and the new species kenotobermorite, Ca 4 Si 6 O 15 (OH) 2 ·5H 2 O ( x = 0 and y = 0). The type locality of kenotobermorite is the N'Chwaning II mine, Kalahari Manganese...
FIGURES
First thumbnail for: The tobermorite supergroup: a new nomenclature
Second thumbnail for: The tobermorite supergroup: a new nomenclature
Third thumbnail for: The tobermorite supergroup: a new nomenclature
Journal Article
Published: 01 April 2007
Mineralogical Magazine (2007) 71 (2): 193–201.
...P. Bonazzi; L. Bindi; O. Medenbach; R. Pagano; G. I. Lampronti; S. Menchetti Abstract Olmiite, ideally CaMn[SiO 3 (OH)](OH), is a newly identified mineral from the N’Chwaning II mine of the Kalahari manganese fields (Republic of South Africa), which occurs as a product of hydrothermal alteration...
FIGURES
First thumbnail for: Olmiite, CaMn[SiO 3 (OH)](OH), the Mn-dominant ana...
Second thumbnail for: Olmiite, CaMn[SiO 3 (OH)](OH), the Mn-dominant ana...
Third thumbnail for: Olmiite, CaMn[SiO 3 (OH)](OH), the Mn-dominant ana...
Journal Article
Published: 01 January 2001
American Mineralogist (2001) 86 (1-2): 147–158.
... ) VIII (Mn 1.95 Fe 0.01 Al 0.04 ) VI [SiO 4 ] 2.07 [H 4 O 4 ] 0.93 from the N’Chwaning II mine at the Kalahari manganese fields, Republic of South Africa, has been studied by single-crystal X-ray diffraction at 100 and 293 K at ambient pressure and up to 8.7 GPa in a diamond-anvil cell at 293 K...
FIGURES
First thumbnail for: Structure, compressibility, hydrogen bonding, and ...
Second thumbnail for: Structure, compressibility, hydrogen bonding, and ...
Third thumbnail for: Structure, compressibility, hydrogen bonding, and ...
Journal Article
Published: 01 December 2000
South African Journal of Geology (2000) 103 (3-4): 231–236.
...B. Cairncross; H. Tsikos; C. Harris Abstract Prehnite is described herein from the N’Chwaning II mine, Kalahari manganese field for the first time. The habit and composition are atypical for the species. The mineral occurs as elongated, prismatic orthorhombic yellow-orange crystals arranged...
FIGURES
First thumbnail for: Prehnite from the Kalahari manganese field, South ...
Second thumbnail for: Prehnite from the Kalahari manganese field, South ...
Third thumbnail for: Prehnite from the Kalahari manganese field, South ...
Journal Article
Published: 01 March 2000
American Mineralogist (2000) 85 (3-4): 563–569.
... vesuvianite, a = 15.487(2), c = 11.764(2) Å from the N’chwaning II mine of the Kalahari manganese fields (RSA). This untwinned crystal has Cu 2+ and Mn 2+ , Mn 3+ forming the square pyramid and exhibits an acentric ordering pattern with 85% string A and 15% string B. This is compared to a reinvestigation...
FIGURES
First thumbnail for: P 4/ n and P 4 nc long-range ordering in low-tempe...
Second thumbnail for: P 4/ n and P 4 nc long-range ordering in low-tempe...
Journal Article
Published: 01 March 2000
American Mineralogist (2000) 85 (3-4): 570–577.
...Thomas Armbruster; Edwin Gnos Abstract Strongly zoned Mn-rich vesuvianites with MnO concentrations up to 14.3 wt% from the N’chwaning II mine of the Kalahari manganese field (South Africa) crystallized at hydrothermal conditions below 450 °C. These vesuvianites are by far the most Mn-rich samples...
FIGURES
First thumbnail for: Tetrahedral vacancies and cation ordering in low-t...
Second thumbnail for: Tetrahedral vacancies and cation ordering in low-t...
Third thumbnail for: Tetrahedral vacancies and cation ordering in low-t...
Image
Infrared absorption spectra of powdered oyelite samples from Bazhenovskoe deposit (a) and N’Chwaning II mine (b).
Published: 01 May 2019
Fig. 3 Infrared absorption spectra of powdered oyelite samples from Bazhenovskoe deposit (a) and N’Chwaning II mine (b).
Image
Scanning electron microscope secondary electron image of elongated prismatic prehnite crystals arranged in parallel groups from N’Chwaning II mine.
Published: 01 December 2000
Figure 3. Scanning electron microscope secondary electron image of elongated prismatic prehnite crystals arranged in parallel groups from N’Chwaning II mine.
Image
Polarized optical absorption single-crystal spectra of the close to end-member henritermierite (sample #97) from the N’Chwaning II mine. Positions ν1–ν4 indicate band peaks and shoulders. The absorber thickness was 19 μm.
Published: 01 April 2004
F ig . 2. Polarized optical absorption single-crystal spectra of the close to end-member henritermierite (sample #97) from the N’Chwaning II mine. Positions ν 1 –ν 4 indicate band peaks and shoulders. The absorber thickness was 19 μm.
Image
Comparison between the X-ray powder diffraction patterns (a), and micro-Raman spectra (b), of tobermorite 10 Å and oyelite from N’Chwaning II mine. The micro-Raman spectra were collected in the same crystallographic orientation, i.e. with the polarization direction parallel to the crystal elongation.
Published: 01 October 2012
Fig. 11 Comparison between the X-ray powder diffraction patterns (a), and micro-Raman spectra (b), of tobermorite 10 Å and oyelite from N’Chwaning II mine. The micro-Raman spectra were collected in the same crystallographic orientation, i.e. with the polarization direction parallel
Image
A cross-section of the Black Rock mine in the west, to the N’chwaning (II and III) mines in the east, illustrating the rock types present, as well as normal and thrust faults (modified after Gutzmer and Beukes, 1995). Projections of the ten drill cores selected for this study are illustrated.
Published: 01 June 2024
Figure 2. A cross-section of the Black Rock mine in the west, to the N’chwaning (II and III) mines in the east, illustrating the rock types present, as well as normal and thrust faults (modified after Gutzmer and Beukes, 1995 ). Projections of the ten drill cores selected for this study
Journal Article
Published: 01 May 2019
European Journal of Mineralogy (2019) 31 (3): 595–608.
...Fig. 2 Bunch of lath-shaped crystals of oyelite. N’Chwaning II mine, Kalahari, South Africa. Scanning electron microscope secondary-electron image. ...
FIGURES
First thumbnail for: Oyelite: new mineralogical data, crystal structure...
Second thumbnail for: Oyelite: new mineralogical data, crystal structure...
Third thumbnail for: Oyelite: new mineralogical data, crystal structure...
Journal Article
Published: 01 April 2004
Mineralogical Magazine (2004) 68 (2): 335–341.
...F ig . 2. Polarized optical absorption single-crystal spectra of the close to end-member henritermierite (sample #97) from the N’Chwaning II mine. Positions ν 1 –ν 4 indicate band peaks and shoulders. The absorber thickness was 19 μm. ...
FIGURES
First thumbnail for: Stabilization of trivalent Mn in natural tetragona...
Second thumbnail for: Stabilization of trivalent Mn in natural tetragona...
Third thumbnail for: Stabilization of trivalent Mn in natural tetragona...
Journal Article
Published: 01 April 1995
American Mineralogist (1995) 80 (3-4): 377–386.
... with calcite, bultfonteinite, and chlorite at N’chwaning mine, located in the Kalahari manganese field, northern Cape Province, South Africa. The aggregates consist of light brown, transparent needles, which average 1.0 x 0.1 x 0.05 mm in size. Nchwaningite is named after the mine N’chwaning II, where...
Journal Article
Published: 01 March 2016
European Journal of Mineralogy (2016) 28 (1): 23–32.
... temperature, are a = 6.7267(5), b = 7.3949(3), c = 22.985(1) Å, β = 123.302(5)°, space group B 11 m . The c parameter is larger than those observed in other “tobermorites” ( e.g. , c = 22.487(4) Å in kenotobermorite from N’Chwaning II mine, South Africa; c = 22.680(4) Å in tobermorite from Urals...
FIGURES
First thumbnail for: Thermal behaviour of Al-rich tobermorite
Second thumbnail for: Thermal behaviour of Al-rich tobermorite
Third thumbnail for: Thermal behaviour of Al-rich tobermorite
Journal Article
Journal: Economic Geology
Published: 01 November 2002
Economic Geology (2002) 97 (7): 1624–1625.
... into enthusiasm when a literature survey revealed the truly gigantic size of the manganese field—and the open playing field offered by the mineralogically complex manganese ores. This initial study, conducted at the N’chwaning II mine, turned later into a M.Sc. thesis that was completed under the guidance...
Journal Article
Published: 01 June 2024
South African Journal of Geology (2024) 127 (2): 421–432.
...Figure 2. A cross-section of the Black Rock mine in the west, to the N’chwaning (II and III) mines in the east, illustrating the rock types present, as well as normal and thrust faults (modified after Gutzmer and Beukes, 1995 ). Projections of the ten drill cores selected for this study...
FIGURES
First thumbnail for: Boron isotopes of Manganese ores from the northern...
Second thumbnail for: Boron isotopes of Manganese ores from the northern...
Third thumbnail for: Boron isotopes of Manganese ores from the northern...