TY - JOUR
A1 - Korges, Maximilian
A1 - Junge, Malte
A1 - Borg, Gregor
A1 - Oberthür, Thomas
T1 - Supergene mobilization and redistribution of platinum-group elements in the Merensky Reef, eastern Bushveld Complex, South Africa
JF - The Canadian mineralogist
N2 - Near-surface supergene ores of the Merensky Reef in the Bushveld Complex, South Africa, contain economic grades of platinum-group elements, however, these are currently uneconomic due to low recovery rates. This is the first study that investigates the variation in platinum-group elements in pristine and supergene samples of the Merensky Reef from five drill cores from the eastern Bushveld. The samples from the Richmond and Twickenham farms show different degrees of weathering. The whole-rock platinum-group element distribution was studied by inductively coupled plasma-mass spectrometry and the platinum-group minerals were investigated by reflected-light microscopy, scanning electron microscopy, and electron microprobe analysis.
In pristine ("fresh") Merensky Reef samples, platinum-group elements occur mainly as discrete platinum-group minerals, such as platinum-group element-sulfides (cooperite-braggite) and laurite as well as subordinate platinum-group elementbismuthotellurides and platinum-group element-arsenides, and also in solid solution in sulfides (especially Pd in pentlandite). During weathering, Pd and S were removed, resulting in a platinum-group mineral mineralogy in the supergene Merensky Reef that mainly consists of relict platinum-group minerals, Pt-Fe alloys, and Pt-oxides/hydroxides. Additional proportions of platinum-group elements are hosted by Fe-hydroxides and secondary hydrosilicates (e.g., serpentine group minerals and chlorite).
In supergene ores, only low recovery rates (ca. 40%) are achieved due to the polymodal and complex platinum-group element distribution. To achieve higher recovery rates for the platinum-group elements, hydrometallurgical or pyrometallurgical processing of the bulk ore would be required, which is not economically viable with existing technology.
KW - Bushveld Complex
KW - Merensky Reef
KW - PGE
KW - PGM
KW - supergene ores
KW - weathering
Y1 - 2021
U6 - https://doi.org/10.3749/canmin.2100023
SN - 1499-1276
VL - 59
IS - 6
SP - 1381
EP - 1396
PB - Mineralogical Association of Canada
CY - Ottawa
ER -
TY - JOUR
A1 - Elsässer, Joshua Philipp
A1 - Hickmann, Thomas
A1 - Jinnah, Sikina
A1 - Oberthur, Sebastian
A1 - Van de Graaf, Thijs
T1 - Institutional interplay in global environmental governance
BT - lessons learned and future research
JF - International environmental agreements: politics, law and economics
N2 - Over the past decades, the growing proliferation of international institutions governing the global environment has impelled institutional interplay as a result of functional and normative overlap across multiple regimes.
This article synthesizes primary contributions made in research on institutional interplay over the past twenty years, with particular focus on publications with International Environmental Agreements: Politics, Law and Economics. Broadening our understanding about the different types, dimensions, pathways, and effects of institutional interplay, scholars have produced key insights into the ways and means by which international institutions cooperate, manage discord, engage in problem solving, and capture synergies across levels and scales.
As global environmental governance has become increasingly fragmented and complex, we recognize that recent studies have highlighted the growing interactions between transnationally operating institutions in the wake of polycentric governance and hybrid institutional complexes.
However, our findings reveal that there is insufficient empirical and conceptual research to fully understand the relationship, causes, and consequences of interplay between intergovernmental and transnational institutions. Reflecting on the challenges of addressing regulatory gaps and mitigating the crisis of multilateralism, we expound the present research frontier for further advancing research on institutional interplay and provide recommendations to support policy-making.
KW - institutional interplay
KW - transnational institutional interplay
KW - global
KW - environmental governance
KW - transnational governance
KW - multilateral
KW - environmental agreements
Y1 - 2022
U6 - https://doi.org/10.1007/s10784-022-09569-4
SN - 1567-9764
SN - 1573-1553
VL - 22
IS - 2
SP - 373
EP - 391
PB - Springer
CY - Dordrecht
ER -