Honours Field School report
The Stellenbosch University Honours class of 2018 made the
great trek (by overnight bus) up from the Cape to the exciting geology of the Kaapvaal
craton. A total of twenty students from both the hard rock geology- and
environmental geochemistry- streams partook in the tour, which focussed
predominantly on various mines located in Gauteng, Mpumalanga, North West and
Limpopo provinces. The tour was led by Dr Bjorn von der Heyden, with invaluable
assistance provided by Masters student Stephan Dunn. First stop on the tour was
the Vredefort Dome, a must-see for any geological excursion upcountry. A
transect through the collar provided students with their first practical
exposure to the Wits stratigraphy, including a brief stop at the auriferous
Amazon Reef conglomerate. The highlights of the visit to the Vredefort dome
however, were undoubtedly the various impact features that were observed
(shatter-cones and pseudotachalyte breccias). Stop two was in the Johannesburg
commercial district, where Matt Mullins from Tecoma Strategies (and a
Stellenbosch University guest lecturer) provided the students with critical
insights into the business aspects of geology and into the importance of
geology to the minerals industry. The next stop was at Exxaro’s North Block
Complex open cast coal mine in the Highveld coal field. For many of the
students, this was their first ever exposure to a mining environment and the
Exxaro team did an outstanding job of introducing students to coal mining and
to the role of the geologist in the mine value chain.
The trip to Barberton comprised a necessary detour via
Tjarkastad to investigate the spinifex textures and pillow lavas of the Onverwacht
Group komatiites and komatiitc basalts respectively. Once in Barberton, an
action-packed itinerary included tours of the Golden Quarry (courtesy of Sheba
Mine), a tour of the BIOX recovery plant (Fairview Mine), and underground
excursion in the Scotia Mine (Chamotte Holdings), and several hours spent
evaluating the numerous exciting stops on the Mokahanje Geotrail. Students also
benefitted greatly from their evening interactions and discussions with their
contemporaries from UKZN- who were also staying at Digger’s retreat in
Barberton whilst we were there. Saturday was spent experiencing some of the
impressive geological features of the Eastern Limb (including the Dwarsrivier
UG1 outcrop, a breccia pipe, and the Magnet Heights outcrop), whereas Sunday
was a more touristic tour along the escarpment with stops at Pilgrim’s Rest,
Pinnacle Falls, Bourke’s Luck Potholes, and the Wolfberg Group stratigraphy).
Week two kicked off with two exciting mine tours in the
Phalaborwa Igneous Complex at Foskor and at Phalaborwa Mining Company. The
students were thus able to experience both open cast and underground mining,
and both mines provided exceptional explanations of their mine water treatment
programs (thereby satisfying the intrigues of our Environmental Geochemistry
students). A trip up to the Northern Limb of the Bushveld Igneous Complex
included a tour of the Zaaiplaats Sn mineralisation in the Bobbejaankop
granites, and road cut observations of the Rooiberg ignimbrites and Waterberg
basal conglomerates (all courtesy of Bushveld Minerals). Our final two days
comprised an impromptu visit to a Rustenberg Grey quarry, a detailed mine tour
of the Vergenoeg fluorspar pipe (Minersa), and some exceptional viewing of Wits
mineralisation in opencast exposures and of tailings retreatment operations
(Mintails Mining).
All companies and individuals who made this tour a great
success are thanked gratefully by the staff and students of Stellenbosch
University. Your time, explanations, and expertise all contributed to an
exciting, practical, and memorable learning experience for our students. Thank
you.