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Onverwacht Pipe

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Journal Article

Andrieslombaardite, RhSbS, a new platinum-group mineral from the platiniferous Onverwacht Pipe, Republic of South Africa Available to Purchase

L.J. Cabri, A.M. McDonald, T. Oberthür, N. Tamura, A. Vymazalová, K.C. Ross, F. Melcher
Published: 01 June 2023
South African Journal of Geology (2023) 126 (2): 151–160.
DOI: https://doi.org/10.25131/sajg.126.0011
..., Mooihoek, and Onverwacht pipes in the eastern Bushveld Complex, South Africa. The mineral and the name were approved by the Commission on New Minerals Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA no. 2022-076) based on data in the co-type samples from...
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View PDF for article title, Andrieslombaardite, RhSbS, a new platinum-group mineral from the platiniferous <span class="search-highlight">Onverwacht</span> <span class="search-highlight">Pipe</span>, Republic of South Africa
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Journal Article

High grade ores of the Onverwacht platinum pipe, eastern Bushveld, South Africa Available to Purchase

Thomas Oberthür, Frank Melcher, Simon Goldmann, Fabian Fröhlich
Published: 08 November 2021
The Canadian Mineralogist (2021) 59 (6): 1397–1435.
DOI: https://doi.org/10.3749/canmin.2100031
...Thomas Oberthür; Frank Melcher; Simon Goldmann; Fabian Fröhlich ABSTRACT The platiniferous dunite pipes are discordant orebodies in the Bushveld Complex. The Onverwacht pipe is a large body (>300 m in diameter) of magnesian dunite (Fo 80–83 ) that crosscuts a sequence of cumulates in the Lower...
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View PDF for article title, High grade ores of the <span class="search-highlight">Onverwacht</span> platinum <span class="search-highlight">pipe</span>, eastern Bushveld, South Africa
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Journal Article

THE PRINCIPAL GEOLOGICAL FEATURES OF THE ONVERWACHT PLATINIFEROUS DUNITE PIPE, EASTERN LIMB OF THE BUSHVELD COMPLEX Available to Purchase

R.N. SCOON, A.A. MITCHELL
Published: 01 September 2010
South African Journal of Geology (2010) 113 (2): 155–168.
DOI: https://doi.org/10.2113/gssajg.113.2.155
...R.N. SCOON; A.A. MITCHELL Abstract The Onverwacht pipe, situated on the leasehold of Eastern Chrome mines in the eastern limb of the Bushveld Complex, warrants preservation as a national monument, as it is the site of the oldest platinum mine in South Africa. The central part of the pipe consists...
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View PDF for article title, THE PRINCIPAL GEOLOGICAL FEATURES OF THE <span class="search-highlight">ONVERWACHT</span> PLATINIFEROUS DUNITE <span class="search-highlight">PIPE</span>, EASTERN LIMB OF THE BUSHVELD COMPLEX
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Diagrammatic geological section across the Onverwacht pipe reproduced from Wagner (1929) by Oberthür et al. (2021) with the scale corrected. Legend from Wagner. 1. Bronzitite with finely disseminated chromite; 2. Lower Chromite; 3. Olivine dunite and wehrlite; 4. Main body of hortonolite-dunite; 4a. Veins of hortonolite-dunite; 5. Vein of diallage-hornblende-hortonolite rock, merging locally into hortonolite-dunite; 6. Upper Chromite; 7. Platinum-bearing rubble and eluvium.

Diagrammatic geological section across the Onverwacht pipe reproduced from ... Available to Purchase

Published: 01 June 2023
Figure 2. Diagrammatic geological section across the Onverwacht pipe reproduced from Wagner ( 1929 ) by Oberthür et al. ( 2021 ) with the scale corrected. Legend from Wagner. 1. Bronzitite with finely disseminated chromite; 2. Lower Chromite; 3. Olivine dunite and wehrlite; 4. Main body
Image
Geological section of the Onverwacht pipe, redrawn from Wagner (1929) and scale corrected. Legend from Wagner (1929): 1 = Bronzitite with finely disseminated chromite, 2 = Lower Chromitite, 3 = Olivine Dunite and Wehrlite, 4 = Main Body of Hortonolite-Dunite, 4a = Veins of Hortonolite-Dunite, 5 = Vein of Diallage-hornblende-hortonolite rock, merging locally into Hortonolite-Dunite, 6 = Upper Chromite, 7 = Platinum-bearing rubble and eluvium.

Geological section of the Onverwacht pipe, redrawn from Wagner (1929) and... Available to Purchase

Published: 08 November 2021
Fig. 2. Geological section of the Onverwacht pipe, redrawn from Wagner (1929) and scale corrected. Legend from Wagner (1929) : 1 = Bronzitite with finely disseminated chromite, 2 = Lower Chromitite, 3 = Olivine Dunite and Wehrlite, 4 = Main Body of Hortonolite-Dunite, 4a = Veins of Hortonolite
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MICROPROBE COMPOSITIONS OF CHROMITE FROM THE ONVERWACHT PIPE, THE WINNAARSH... Available to Purchase

Published: 08 November 2021
TABLE 4. MICROPROBE COMPOSITIONS OF CHROMITE FROM THE ONVERWACHT PIPE, THE WINNAARSHOEK PIPE, AND THE LG-6 CHROMITITE LAYER.
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SUMMARY OF MAJOR PGM IDENTIFIED IN THE ONVERWACHT PIPE ORES ( n = 338 GRAI... Available to Purchase

Published: 08 November 2021
TABLE 5. SUMMARY OF MAJOR PGM IDENTIFIED IN THE ONVERWACHT PIPE ORES ( n = 338 GRAINS) IN COMPARISON TO THE SUITE OF PGM REPORTED FROM THE DRIEKOP PIPE BY MELCHER & LODZIAK (2007)
Image
Geological map of the Onverwacht pipe based on surface mapping at a scale of 1:500. Geological features and infrastructure located from the glory hole, roads etc by means of tape and compass. Base plan and contours from 1:10,000 scale orthophotographs. Drill-hole collars and position of vertical shaft provided by Eastern Chrome mines. Inclination of mineralized core-zone (78.5° at 118°) after Wagner (1929). Perimeter of the pipe estimated from surface outcrops and soil type. AB and CD=section lines presented here; XY=estimated position of section line of Cameron and Desborough (1964).

Geological map of the Onverwacht pipe based on surface mapping at a scale o... Available to Purchase

Published: 01 September 2010
Figure 4. Geological map of the Onverwacht pipe based on surface mapping at a scale of 1:500. Geological features and infrastructure located from the glory hole, roads etc by means of tape and compass. Base plan and contours from 1:10,000 scale orthophotographs. Drill-hole collars and position
Image
Geological section CD of the Onverwacht pipe aligned at 084° and looking approximately north. Corresponds to the alignment of Wagner’s (1929) section. The MG1 and LG6 layers are correlated with Wagner’s Upper and Lower Chromitites, respectively. The LG7 was not shown on Wagner’s section. The three-dimensional shape of the magnesian dunite and harzburgite is in part schematic, as the contact with the feldspathic orthopyroxenite wall rocks is diffuse. The sheets and fingers of magnesian dunite and harzburgite are based on drill-hole logs. Similar sheets and fingers probably occur at depth but have been omitted due to lack of data. The steepening in the dip of the chromitite layers is based on mapping and drill-hole logs. Interpretation of the chromitite slabs (main stock and core-zone) as xenoliths of the LG6 layer, and the Ti-magnetite segregations (core-zone) as altered xenoliths of the LG7 layer suggests that these features have been transported downwards.

Geological section CD of the Onverwacht pipe aligned at 084° and looking ap... Available to Purchase

Published: 01 September 2010
Figure 7. Geological section CD of the Onverwacht pipe aligned at 084° and looking approximately north. Corresponds to the alignment of Wagner’s (1929) section. The MG1 and LG6 layers are correlated with Wagner’s Upper and Lower Chromitites, respectively. The LG7 was not shown on Wagner’s
Image
(A) Section of the Onverwacht pipe (redrawn from Wagner, 1925c). Rock descriptions have been simplified and updated. (B) Section of the Onverwacht pipe (redrawn from Wagner, 1925d). In (a) the mineralized core-zone was depicted as an irregular lens, whereas in (b) the pipe-like form was revealed by mining activities. Note that even in (a) the primary layering in the wall rocks was distinguished, largely from persistent outcrops of the LG6 chromitite (formerly known as the Steelpoort seam), to the east of the linear ridge, and the MG1 chromitite (our interpretation), on the western slope. Location of LG7 chromitite not shown as this layer only crops out around the perimeter of the pipe in one locality.

( A ) Section of the Onverwacht pipe (redrawn from Wagner, 1925c ). Rock d... Available to Purchase

Published: 01 December 2004
Figure 5. ( A ) Section of the Onverwacht pipe (redrawn from Wagner, 1925c ). Rock descriptions have been simplified and updated. ( B ) Section of the Onverwacht pipe (redrawn from Wagner, 1925d ). In (a) the mineralized core-zone was depicted as an irregular lens, whereas in (b) the pipe-like
Journal Article

The Mooihoek Platinum Pipe, Eastern Bushveld Complex, South Africa – Geochemistry and Mineralization Available to Purchase

Thomas Oberthür, Simon Goldmann, Frank Melcher
Published: 20 July 2023
The Canadian Journal of Mineralogy and Petrology (2023) 61 (3): 507–535.
DOI: https://doi.org/10.3749/2200066
.... The main findings are as follows: Chondrite-normalized distribution patterns of the PGE in the Mooihoek samples demonstrate that mainly Pt is strongly enriched relative to the other PGE and Au. The shapes of the patterns are subparallel to each other and also to those of the Onverwacht pipe, indicating...
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View PDF for article title, The Mooihoek Platinum <span class="search-highlight">Pipe</span>, Eastern Bushveld Complex, South Africa – Geochemistry and Mineralization
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The platiniferous dunite pipes in the eastern limb of the Bushveld Complex: Review and comparison with unmineralized discordant ultramafic bodies Available to Purchase

Roger N. Scoon, Andrew A. Mitchell
Published: 01 December 2004
South African Journal of Geology (2004) 107 (4): 505–520.
DOI: https://doi.org/10.2113/gssajg.107.4.505
...Figure 5. ( A ) Section of the Onverwacht pipe (redrawn from Wagner, 1925c ). Rock descriptions have been simplified and updated. ( B ) Section of the Onverwacht pipe (redrawn from Wagner, 1925d ). In (a) the mineralized core-zone was depicted as an irregular lens, whereas in (b) the pipe-like...
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View PDF for article title, The platiniferous dunite <span class="search-highlight">pipes</span> in the eastern limb of the Bushveld Complex: Review and comparison with unmineralized discordant ultramafic bodies
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Journal Article

ALLUVIAL AND ELUVIAL PLATINUM-GROUP MINERALS FROM THE BUSHVELD COMPLEX, SOUTH AFRICA Available to Purchase

T. OBERTHÜR, T.W. WEISER, F. MELCHER
Published: 01 December 2014
South African Journal of Geology (2014) 117 (2): 255–274.
DOI: https://doi.org/10.2113/gssajg.117.2.255
...T. OBERTHÜR; T.W. WEISER; F. MELCHER Abstract The present work provides an initial description of detrital platinum-group minerals (PGM) collected from alluvial sediments of rivers draining the Bushveld Complex, and from eluvial concentrations at the Onverwacht platiniferous pipe. During a field...
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View PDF for article title, ALLUVIAL AND ELUVIAL PLATINUM-GROUP MINERALS FROM THE BUSHVELD COMPLEX, SOUTH AFRICA
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PROPORTIONS (NUMBER OF GRAINS IN %) OF MAJOR PGM AND PGM GROUPS IDENTIFIED ... Available to Purchase

Published: 20 July 2023
TABLE 3. PROPORTIONS (NUMBER OF GRAINS IN %) OF MAJOR PGM AND PGM GROUPS IDENTIFIED IN THE MOOIHOEK PIPE ORES IN COMPARISON TO THE SUITES OF PGM REPORTED FROM THE DRIEKOP PIPE AND THE ONVERWACHT PIPE
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(A) NiO (wt.%) versus forsterite (Fo in at.%) contents of olivine from the Mooihoek (squares) and Onverwacht (circles; data from Oberthür et al. 2021) pipes. Electron probe microanalyses; compare data in Table 2. Ore samples = full symbols, Onverwacht = orange, Mooihoek = yellow. Barren Mg-dunite pipes = open symbols. Mg-dunite, Jagdlust = diamond (green). IRUP, Smokey Hills Mine = X. Dike, exposure in road cut south of Mooihoek pipe = +. Note that a comma is used as the decimal marker. Fig. 4. (B) MnO (wt.%) versus forsterite (Fo in at.%) contents of olivine from the Mooihoek and Onverwacht pipes. Electron probe microanalyses; compare data in Table 2. Symbols as in Figure 4A. Note that a comma is used as the decimal marker.

(A) NiO (wt.%) versus forsterite (Fo in at.%) contents of olivine from th... Available to Purchase

Published: 20 July 2023
Fig. 4. (A) NiO (wt.%) versus forsterite (Fo in at.%) contents of olivine from the Mooihoek (squares) and Onverwacht (circles; data from Oberthür et al . 2021 ) pipes. Electron probe microanalyses; compare data in Table 2 . Ore samples = full symbols, Onverwacht = orange, Mooihoek = yellow
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Forsterite (Fo in at.%) versus NiO (wt.%) contents of olivine from the Onverwacht pipe. Electron probe microanalysis; compare data set in Table 3. Ore zone of inner ore pipe = full circles, Mg-dunite pipe = open circle.

Forsterite (Fo in at.%) versus NiO (wt.%) contents of olivine from the On... Available to Purchase

Published: 08 November 2021
Fig. 4. Forsterite (Fo in at.%) versus NiO (wt.%) contents of olivine from the Onverwacht pipe. Electron probe microanalysis; compare data set in Table 3 . Ore zone of inner ore pipe = full circles, Mg-dunite pipe = open circle.
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Field activities: (A) Panning of alluvial PGM, Dwars River, Der Brochen, south of dam. (B) Onverwacht Pipe (in the background), and eastern slope (foreground) that was sampled for eluvial PGM. Inset: largest (1.87 mm) eluvial PGM grain (Pt-Fe alloy) found at Onverwacht (grain 4/55).

Field activities: ( A ) Panning of alluvial PGM, Dwars River, Der Brochen, ... Available to Purchase

Published: 01 December 2014
Figure 2 Field activities: ( A ) Panning of alluvial PGM, Dwars River, Der Brochen, south of dam. ( B ) Onverwacht Pipe (in the background), and eastern slope (foreground) that was sampled for eluvial PGM. Inset: largest (1.87 mm) eluvial PGM grain (Pt-Fe alloy) found at Onverwacht (grain 4/55).
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Generalized geology of the Bushveld Complex showing the stream sampling localities described in this study (1 to 6), and location of the Onverwacht Pipe (X).

Generalized geology of the Bushveld Complex showing the stream sampling loc... Available to Purchase

Published: 01 December 2014
Figure 1 Generalized geology of the Bushveld Complex showing the stream sampling localities described in this study (1 to 6), and location of the Onverwacht Pipe (X).
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Contour plan showing the location of drill-holes and downwarping of the LG6 chromitite layer in the vicinity of the Onverwacht pipe (in part based on plans provided by Eastern Chrome mines).

Contour plan showing the location of drill-holes and downwarping of the LG6... Available to Purchase

Published: 01 September 2010
Figure 6. Contour plan showing the location of drill-holes and downwarping of the LG6 chromitite layer in the vicinity of the Onverwacht pipe (in part based on plans provided by Eastern Chrome mines).
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Chondrite normalized PGE distribution pattern of ores from the Mooihoek pipe (average of 18 ore samples &gt;3 ppm Pt) and the Onverwacht pipe (average of 13 ore samples &gt;5 ppm Pt; Oberthür et al. 2021) in comparison to the Merensky Reef of the western Bushveld Complex (Barnes &amp; Maier 2002). C-1 chondrite values from McDonough &amp; Sun (1995).

Chondrite normalized PGE distribution pattern of ores from the Mooihoek pip... Available to Purchase

Published: 20 July 2023
Fig. 3. Chondrite normalized PGE distribution pattern of ores from the Mooihoek pipe (average of 18 ore samples >3 ppm Pt) and the Onverwacht pipe (average of 13 ore samples >5 ppm Pt; Oberthür et al . 2021 ) in comparison to the Merensky Reef of the western Bushveld Complex ( Barnes