Stamp mills were widely used in South Africa during the late 19th and early 20th centuries for gold ore processing, particularly in the Witwatersrand goldfields (Johannesburg area). Here’s an overview of their role in South African gold mining:
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Stamp Mills in South African Gold Mining
1. Function:
– Stamp mills crushed gold-bearing rock into fine powder to liberate gold particles.
– Heavy metal stamps (attached to a rotating camshaft) pounded ore fed into a mortar box.
– Water was often added to create a slurry, which was then processed further (e.g., via mercury amalgamation or cyanidation).
2. Historical Significance:
– Introduced in the 1880s–1890s during the Witwatersrand Gold Rush.
– Critical for processing low-grade ores from deep-level mines.
– Replaced by more efficient technologies (e.g., ball mills, cyanidation) by the mid-20th century.
3. Key Locations:
– Johannesburg/Pilgrim’s Rest/Barberton: Early stamp mills supported small-scale and large-scale mining.
– Randfontein Estates: One of the largest stamp mills operated here in the early 1900s (120 stamps).
4. Decline & Legacy:
– By the 1930s–1950s, stamp mills became obsolete due to high energy costs and inefficiency.
– Some preserved stamp mills can be seen at museums like:
– The Johannesburg Gold Reef Ci.jpg)
Museum
– The Pilgrim’s Rest Mining Museum (Mpumalanga)
Modern Alternatives
– Today, South African gold mining uses:
– Ball mills, autogenous grinding (AG), and cyanide leaching for higher recovery rates.
– Advanced techniques like carbon-in-pulp (CIP) and froth flotation.
Would you like details on specific historical mines or preservation sites?