Chromite is iron magnesium chromium oxide: (Fe, Mg)Cr2O4. It is an oxide mineral belonging to the spinel group. Magnesium can substitute for iron in variable amounts; also, aluminium and ferric iron commonly substitute for chromium.

Cobalt is extracted from a number of minerals, the main ones being smaltite, (CoNi)As3; linnaeite, Co3S4; cobaltite, CoAsS; and glaucodot, (CoFe)AsS.

Currently, the most common source of copper ore is the mineral chalcopyrite (CuFeS2), which accounts for about 50% of copper production. The focus of this article is on the process of copper extraction from chalcopyrite ore into pure metal. Processes for other minerals are mentioned.

Lead is a main-group element with symbol Pb (Latin: plumbum) and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metals. Lead has a bluish-white color when freshly cut, but tarnishes to a dull grayish color when exposed to air. It has a shiny chrome-silver luster when melted into a liquid.

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, deep purple, to rusty red. The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH)), limonite (FeO(OH).n(H2O)) or siderite (FeCO3). Hematite is also known as "natural ore". The name refers to the early years of mining, when certain hematite ores contained 66% iron and could be fed directly into iron making blast furnaces.