pachuca tank \pa*chu"ca tank\ (Metallurgy)
A high and narrow tank, with a central cylinder for the
introduction of compressed air, used in the agitation and
settling of pulp (pulverized ore and water) during treatment
by the cyanide process; -- so named because, though
originally devised in New Zealand, it was first practically
introduced in Pachuca, Mexico.
[Webster 1913 Suppl.]