On 24 December 1880, a Boer Commando of 600 men entered the town and on 27 December, demanded the surrender of the British garrison which was promptly refused by the Garrison Commander, Captain Auchinleck. The siege of Rustenburg commenced on 27 December 1880 and ended on 30 March 1881, lasting for 93 days. During the siege, the British garrison was subjected to privations and sickness and it also rained continuously for 45 days of the siege. The Boers had prepared a trench, close to the fort and on 4 February 1881, Captain Auchinleck and nine men, after dark, started their advance on the trench. Captain Auchinleck and his men had reached a point, 27 metres from the trench when they drew fire from the Boers in the trench. Captain Auchinleck and his men succeeded in driving the occupants from the trench, after which the Boer Commando fired on the fort from all directions. Captain Auchinleck was wounded in the elbow, his second bullet wound that day.
On 14 March 1881, the Boers notified the British garrison in the fort about the terms of the truce and on 30 March, Lieutenant Ryder, of the 60th Rifles, arrived from Sir Evelyn Wood's camp with a message that peace had been negotiated. The British garrison sustained few casualties during the siege; Captain Auchinleck was wounded four times while three other men sustained wounds, two of them serious.
Captain Auchinleck was killed in Burma in 1884 during an attack on the important town of Toungwingyu.[4]