Ezeokoli, Obinna T.
Bezuidenhout, Cornelius C.
Maboeta, Mark S.
Khasa, Damase P.
Adeleke, Rasheed A.
Funding for this research was provided by:
Coaltech Research Association NPC, South Africa (Project 9.22)
National Research Foundation South Africa (118812 and 119758)
Article History
Received: 15 July 2019
Accepted: 13 January 2020
First Online: 4 February 2020
Competing interests
: The authors declare no competing interests.