One of the least known quarries of the Cape Peninsula, and not easy to spot, was worked on Seaforth beach in 1865, where granite was shaped on site to re-enforce the shaky foundation of Roman Rock lighthouse, built only a few years earlier in 1861.This well known False Bay “landmark” (if one may call it that) is South Africa’s only lighthouse built on a rock at sea, which becomes visible at low tides.Stonemasons were employed to carefully chisel out 4 ton rounded sections, which were first assembled on the beach to make sure they fitted together perfectly, then taken to the lighthouse on a specially made barge.They were offloaded by a derrick attached to the pier jutting out from the lighthouse, and pulled to the tower by an aerial railway, and from there carefully assembled around the base in waist high water.“The Commander, continuing his journey along the beach, met three company’s servants and black boy, all stationed at the mines at the Steenbergen, having with them two muskets.” They claimed to be searching for runaway slaves but were probably enjoying a hunting trip, being normally far from the Castle’s prying eyes.Four months later a Johann Vogel visited the “Steinberg” and found the mines ruined.This was impossible as the barge was never docked anywhere near the bottom of the chute.The mining methods proved slow and in 1910 some 5000 tons of ore were produced, but in 1911 a mere 130 tons.
The nearest source of granite was the large boulders on the seashore, which could be worked wherever they had been exposed on the surface.
The best known of the “silver mines” is the old Zilvermyn alongside Ou Kaapse Weg on the Steenberg, and is one of three mines, the others being on either side of the Silvermine River in the valley below.
They are dated 1687 from an entry in the Company’s diary on 15 November, when Van der Stel was making a journey to what would be later called Simon’s Town in his honour.
TVJThe Western Cape has a number of manganese deposits but the reserves are not large, and some have a high phosphorus level.
In the Peninsula deposits were known and worked on Constantiaberg in 1880, but the best deposit is on the mountain slopes above present day Chapman’s Peak Drive, near Hout Bay.