Excess graphite may have led to deadly Denel blast

CAPE TOWN - “Static electricity build-up” coupled with “human error when excess graphite was added to (material)” are suspected to be the cause of the deadly Rheinmetall Denel Munition (RDM) explosion in 2018 which claimed the lives of eight workers.

This emerged when independent investigator and chemical engineer Roderick Keyser, who had conducted an investigation into the explosion, testified before the public inquiry into the incident, which resumed on Tuesday.

Nico Samuels, 41, team leader Stevon Isaacs, 51, operators Mxolisi Sigadla, 40, Bradley Tandy, 19, Jamie Haydricks, 24, Jason Hartzenberg, 22, Triston David, 22, and Thandolwethu Mankayi, 27, were killed in the incident in Somerset West.

Keyser said their investigation was conducted in a “risk-based methodology” which explored and analysed friction, heat and impact.

Speaking to the possibility that a new valve being replaced at the N16 plant of RDM – where the CBI single-base propellant was being produced (a process in which Samuels had been part of) – could have been a possible cause of the explosion, Keyser in his findings said the change from a “butterfly valve” to an “iris mucon valve” could not be attributed as a possible cause of the explosion.

Keyser further said the propellant had been produced at RDM for a very long time without an explosion incident.

In his findings report, Keyser further submitted that “oversteeping, reworking and excess graphite” could have been what attributed to the static electricity build-up, which “is a well-known risk in propellant manufacturing”.

Edward Daniels, an employee and colleague of Samuels, relived the tragedy when he was one of 17 witnesses called to give testimony during the second sitting of the inquiry on Tuesday.

He worked as a team leader in the mixing, pressing and cutting department on the fateful day, September 3, 2018, and described Samuels – who had worked at the site for more than two decades – as one who was a “bright guy, hard-working and would never jeopardise anyone’s safety”.

Daniels heard the explosion from his home where he was asleep as he was to work the night shift.

An operator at RDM and witness called to testify, Kevin Williams, said he was called to work overtime on the Saturday preceding the event as “they were in a hurry for the CBI for Monday”.

Another witness and employee of RDM, Randall Flandorp, who worked as a team leader, after being questioned if there was production pressure on the day of the explosion, said: “Whenever people had to work overtime, there was pressure.”

“But I always said to my team that they should not rush. I always said to them ’We are not working with peanuts or sweets and this stuff can kill you.’”

The inquiry continues.