Gold is widely diffused, and abandoned "washings" all over the state show how general the industry was at one time.
At some distance from the shaft a square water-tight wall was built, and the space between it and the shaft was filled in with sand, which was purified of all saline matter by repeated washings; on the ground-level perforated stones set at the four corners of the basin admitted the rain-water, which was discharged from the roofs by lead pipes; this water filtered through the sand and percolated into the shaft of the well, whence it was drawn in copper buckets.
of gold representing a value of 168,626 were obtained from the mines and alluvial washings.
Gold was discovered by the Portuguese soon after their settlement of the coast in the 16th century, but the washings were poor and attracted little attention.
It was at one time proposed to treat the concentrated black iron obtained in the Ural gold washings, which consists chiefly of magnetite, as an iron ore, by smelting it with charcoal for auriferous pigiron, the latter metal possessing the property of dissolving gold in considerable quantity.