31 May 1980
Three attacks were launched on the night of 31 May/1 June at Sasol I and NATREF in Sasolburg and Sasol II in Secunda to coincide with Republic Day. Reconnaissance for the attacks was made in June 1979 by members of African National Congress (ANC) armed wing Umkhonto we Sizwe and two groups of cadres were trained in Angola to execute these operations. The final reconnaissance was done on the eve of the attacks. The team that launched attacks in Sasol I and NATREF, remained in the country before retreating to Mozambique via Swaziland. The executors of the operations in Secunda drove off to Swaziland straight away after the attack and proceeded with their journey the next morning to their final destination in Mozambique. No one was killed in these attacks but a security guard in Sasol I sustained injuries. Two perpetrators, David Motshwane Moisi and Sipho Matthews Thobela, were later granted amnesty by the Truth and Reconciliation Commission (TRC) for the Sasol II attacks.  
References

CASE NO: AC/2001/003, TRUTH AND RECONCILIATION COMMISSIONAMNESTY COMMITTEE, from the Department of Justice and Constitutional Development, [online], Available at www.justice.gov.za    [Accessed: 27 May 2013]