Abstract:
The Madzaringwe Formation in the Vele colliery is one of the coal-bearing Late Palaeozoic
units of the Karoo Supergroup, consisting of shale with thin coal seams and sandstones. Maceral
group analysis was conducted on seven representative coal samples collected from three existing
boreholes—OV125149, OV125156, and OV125160—in the Vele colliery to determine the coal rank and
other intrinsic characteristics of the coal. The petrographic characterization revealed that vitrinite is
the dominant maceral group in the coals, representing up to 81–92 vol.% (mmf) of the total sample.
Collotellinite is the dominant vitrinite maceral, with a total count varying between 52.4 vol.% (mmf)
and 74.9 vol.% (mmf), followed by corpogelinite, collodetrinite, tellinite, and pseudovitrinite with a
count ranging between 0.8 and 19.4 vol.% (mmf), 1.5 and 17.5 vol.% (mmf), 0.8 and 6.5 vol.% (mmf)
and 0.3 and 5.9 vol.% (mmf), respectively. The dominance of collotellinite gives a clear indication
that the coals are derived from the parenchymatous and woody tissues of roots, stems, and leaves.
The mean random vitrinite reflectance values range between 0.75% and 0.76%, placing the coals
in the medium rank category (also known as the high volatile bituminous coal) based on the Coal
Classification of the Economic Commission for Europe (UN-ECE) coal classification scheme. The
inertinite content is low, ranging between 4 and 16 vol.% (mmf), and it is dominated by fusinite with
count of about 1–7 vol.% (mmf). The high amount of inertinite, especially fusinite, with empty cells
and semi-fusinite in the coals will pose a threat to coal mining because it aids the formation of dust.
