The Hörder (Hoerder) Bergwerks-und Hütten-Verein , or Hörder Verein for short, was a mining and iron company in Dortmund.
In 1852, construction began on the first blast furnace (later called Phoenix-Ost).
In 1879 a licence was obtained from Sidney Gilchrist Thomas for the new Thomas process. The Thomas steelworks built in 1880.
See Wikipdia entry.