Workers huddle around a piece of equipment
known as a "giant stonebreaker."
Launders used gravity to drain water from the mines. Flooding was a constant danger.
The revolving barrel in this picture were used
to prepare chloroauric acid, a
necessary ingredient for the Wohlwill Process.
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Mining Technology of the 1890s
click any of the photos for more detail.
Though the 1890s evoke images of a historic past, the mining
operations at Morro Velho in that decade actually employed a significant
amount of technology. Power plants produced the electricity that ran drilling and
crushing equipment, cable cars, power saws and other tools, and lighting systems. (Prior
to electric lighting, the use of oil lamps had caused a catastrophic fire at Morro Velho
in 1867.) Other devices made use of natural forces such as gravity.
Flooding was a constant concern of any deep excavation such as that at
Morro Velho. As such, the Saint John d'El Rey Company employed a number
of divers in case of emergency. Of course, preventing flooding altogether
remained preferable. The works at Morro Velho featured launders to help drain the mines.
Launders had been used since prehistoric times, with the most primitive being little more
than hollowed out logs laid at an incline. The launders at Morro Velho made use of
mechanized weirs to assist gravity.
The production of gold through the removal of impurities in the ore also
employed fairly advanced technology. The Wohlwill Process, invented in
1874, involved melting ore with acid and then subjecting it to electrolysis.
The gold would accumulate on gold cathodes, and the other minerals, such as silver,
would settle out as particulates. The process was used at Morro Velho and resulted in
99.999% pure gold. It remains the preferred method of gold production today.
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The Saint John d'El Rey Company employed
divers in case of flooding.
Water drains out of the mine and
into a weir
via the launders.
Workers prepare the electrolysis
chambers for gold purification.
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