Abstract:
South Africa is one of the leading producers and exporters of coal globally. A significant amount of the
country’s production is obtained from previously mined underground bord and pillar workings. This
coal is in the form of pillars and remnants on the roof and floor of the old workings. The good quality coal
pillars were left behind as primary support during underground bord and pillar mining operations. Due
to the depletion of virgin coal reserves, the pillars and remnant coal are now removed using opencast
mining rather than underground methods. However, the secondary extraction of pillars and remnant
coal from the old workings using opencast methods entails some serious challenges that have a negative
impact on the safety and productivity of the operations, affecting both personnel and machinery. If these
risk factors and challenges are managed properly, then the opencast mining operations could remove the
pillars safely at recoveries competitive with those of virgin coal operations. In this study we review the
recurring challenges affecting opencast pillar mining by means of field investigations and consultations
with experts at five opencast pillar mining operations, and evaluate the best practices used to combat
these challenges. It was found that each mine has its own unique conditions and challenges.
