1 Correction to: Int J Coal Sci Technol (2020) 7(1):26–42 https://doi.org/10.1007/s40789-020-00303-6

In this article, Professor Nikki Wagner (Department of Geology, University of Johannesburg, South Africa) raised the following concerns in the data presented in Tables 1 and 2.

  1. 1.

    In Table 1, the sum of proximate data (ash + moisture + fixed carbon + volatile matter) which is far above 100% for Lamja2, Garin-Maiganga, Okaba and Lafia-Obi coal samples.

  2. 2.

    In Table 1, the sum of ultimate data (total sulphur + carbon, nitrogen + hydrogen + oxygen) is far below 50% for Enugu and Imiegba coal samples.

  3. 3.

    In Table 2, the sum of macerals (vitrinite + inertinite + lipnite + mineral matter) which is far above 100% for Enugu and Imiegba coal samples.

Corrections:

Table 1: Proximate analyses (as-received basis) and ultimate analyses (dry basis; C, H, N, total S, and O by difference). The derived values (O/C, H/C and VM/FC), heating value parameters (HHV and LHV) and mineral matter (MM) of coals.

Table 2: Macerals, subtotals of vitrinite submacerals (in italics), and totals of maceral groups and of minerals (in italics) along with the vitrinite maximum and random reflectances and the respective standard deviations of the reflectances. Note that the first column for each coal includes the minerals in the total and the second column is the mineral-free normalization of the maceral content.

Table 1 Proximate and ultimate analyses of Cretaceous coals from Benue Trough Basin (n = 3)
Full size table
Table 2 Maceral composition (mineral matter free basis, mmf) and mean reflectance of Cretaceous coals from the Benue Trough. Macerals, subtotals of vitrinite submacerals (in italics), and totals of maceral groups and of minerals (in italics) along with the vitrinite maximum and random reflectances and the respective standard deviations of the reflectances. Note that the first column for each coal includes the minerals in the total and the second column is the mineral-free normalization of the maceral content
Full size table