The 1950s in Brazil were marked by euphoria from the unexpected boom of commercial pig iron production. Every larger town in the state of Minas Gerais had at least one blast furnace plant and Pará de Minas was to be no exception.

Djalma Marcal Rezende came up with the idea to set up the first ironworks founded ´Sideralta´ 1958. However this name did not catch on and the works were soon renamed ´Siderúrgica Alterosa´.

Blast furnace No 1 was put into operation in 1959. Nevertheless in the same year, the town of Pará de Minas suffered a catastrophic drought that lasted for 6 years. The ironworks had to deal with frequent blackouts, which negatively affected the first years of operation.

Despite this, the second blast furnace was built in 1962 and, when the market recovered, the third blast furnace was put into operation in 1969.

From the mid-1960s, Alterosa began to invest in its own sources of eucalyptus wood to produce charcoal.

Today, the annual production of pig iron is 288,000 tonnes.