Raw materials and supplies were unloaded from ships and pig iron was loaded onto ships docked at a pier built for that purpose which extended about 1,400 feet (430 m) into Lake Superior. Charcoal made in Onota was also transported to furnaces in and around Marquette. Iron smelting began in the spring of 1870, producing 3,498 tons of pig iron that year. In 1871, the product was 3,597 tons, and 4,900 tons in 1872. In 1872, a second stack was built and began production in December.