Abstract
Following an uncontrolled detonation of explosives in one of the open cast mining pits located in the central Witbank Coalfield (2018). The premature detonation of explosives poses a fatal risk to employees working in the surrounding area. Therefore, it is important to investigate all possible contributing factors that could lead to an uncontrolled detonation of explosives to reduce the risk of future incidents. One of the aspects identified as a possible contributing factor for the uncontrolled detonation is known as reactive ground. Reactive ground is defined as ground in which the reaction between sulfides (especially iron and copper sulfides) contained in rock and the ammonium nitrate contained in explosives may take place. Four boreholes were drilled in each of the four active mining pits of the South32 mine in question. The boreholes were logged and sampled, thus the database of this project consists of 16 boreholes and a total of 255 samples. Chemical compatibility tests were done on a total of 255 samples, to determine whether any of the mining pits in question has the potential for reactive ground. Tests concluded that the mine has eight out of the ten reactive ground indicators present. Even though the chemical compatibility test proved to be negative, the presence of eight reactive ground indicators indicate conditions conducive for reactive ground are present, providing all contributing factors line up. It is unlikely that the uncontrolled detonation event that occurred on 10 February 2018 at the mine was due to reactive ground. Pit A (the pit in which the initial event occurred) does not have a history of recorded hot holes thus it is unlikely that the rock-explosive reaction was brought on by heat. The temperature of the blasthole in which the uncontrolled detonation took place was also taken prior to charging as per SOP requirements; the average blasthole temperature was recorded as +/-25⁰C. The sleep time of the explosives were also limited to < 8 hours. ..
M.Sc. (Geology)