After the British occupation of Pretoria in June 1900, many Boers returned disillusioned to their farms and the decision to continue the war was not widely supported. The Boer leaders urgently needed a victory to revive morale and help the recruitment of reluctant burghers to rejoin the commandoes. General JH de la Rey saw an opportunity to achieve this by disrupting communications west of Pretoria. He moved one of his commandoes along the north of the Magaliesberg towards Silkaatsnek and Kommandonek, two of the mountain passes on the road between Pretoria and Rustenburg (close to the present Hartbeespoort Dam). That day Lt Col. the Hon. W.P. Alexander commanding the British garrison at Kommandonek was joined by a second force comprising a battalion of the Lincoln Regiment and a cavalry squadron of Scots Greys under the command of Colonel H.R. Roberts.
Roberts was due to join up with a column from Krugersdorp the following day and continue to Rustenburg. That night he camped below the cliffs of Silkaatsnek but unwisely failed to place guards on the summit above his camp. During the night De la Rey's commandos climbed the mountain and at first light on 11 July they were looking directly down into the British camp. When the attack began Roberts's guns were ineffective because they were too close to the mountain and could not be elevated enough to fire on the Boers above. Men were sent deeper into the pass but were soon surrounded and trapped. Alexander based nearby at Kommandonek was called upon to help and he shelled the Boer positions for a short while but then inexplicably decided that the day was lost and that he should withdraw to avoid defeat of his own force. Abandoned without any assistance, Roberts and his men fought on until evening when they were obliged to surrender.
Thirty kilometers away the column with which Roberts was due to rendezvous was in similar trouble. General Sarel Oosthuizen had positioned a commando of about 750 men on high ground overlooking the road from Krugersdorp. As the British column under Major-General H.A. Smith-Dorrien approached on the morning of 11 July the well-concealed Boers attacked. Badly deployed on an exposed hill, Smith-Dorrien's artillery was trapped and their horses killed in the gun carriages. Bravely, the gunners continued defending their guns and before long only 13 of the 16 were wounded. The fighting was fierce on both sides and two Victoria Crosses were won by Captains W.E. Gordon and D.R. Younger. Sarel Oosthuizen, one of the most prominent Boer generals, was mortally wounded during a final charge in the late winter afternoon. Only after dark were the British able to limp back to Krugersdorp. Both sides had suffered severe losses but the Boers had successfully sealed off British communication between Rustenburg and the Witwatersrand and had convincingly reestablished their competence in the field.