Coal of Africa down nearly 18 percent as workers strike JOHANNESBURG (Reuters) - Johannesburg-listed shares of Coal of Africa (CZAJ.J) plummeted nearly 18 percent in Johannesburg after the company confirmed some of its staff at the Mooiplaats Colliery started a legal strike on Tuesday. Coal of Africa is down 17.78 percent at 1.85 rand, compared to a 0.38 percent decline by the All-share index .JALSH. Reporting by Helen Nyambura-Mwaura; Editing by Ed Stoddard