Casting

Casting in the metals and mining value chain refers to the industrial process of pouring or directing molten metal into molds or through continuous casting machines to solidify it into specific shapes — such as ingots, billets, slabs, rods, or specialized components — that can be further processed by fabricators or used directly as commercial products. In the aluminum sector, which processes alumina derived from bauxite through electrolytic reduction, casting is the final step in primary metal production and occurs within the casthouse. The direct chill (DC) casting process is the dominant method for producing wrought aluminum products: molten aluminum is poured into a water-cooled, open-ended mold of appropriate cross-section, and as it begins to solidify at the mold wall, the partially formed ingot is progressively lowered while direct water cooling sprays solidify the remaining molten core from outside. This produces rolling ingots of up to 10 tonnes and extrusion billets of various diameters (commonly 5-12 inches in diameter and several meters long). Continuous casting — including wheel-and-belt casting and twin-roll casting — produces strip and rod products in a continuous operation, eliminating the need for the reheating and hot rolling steps required after DC casting. In the gold mining sector, casting refers to the pouring of molten doré metal (a gold-silver alloy from smelting) into molds to produce doré bars for shipment to gold refineries, where the gold is further refined to market-deliverable 99.5% or 99.99% fine gold bars conforming to London Bullion Market Association (LBMA) good delivery standards. In iron foundry applications relevant to mining equipment manufacturing, casting involves pouring molten iron or steel into shaped molds to produce wear-resistant mill liners, crusher jaws, and equipment components.