This instrument grants a tariff concession for specific alumina‑plant industrial parts — namely digestion and/or evaporation flash vessels classified under customs code 8419.90.90 — allowing preferential duty treatment (Item 50, Schedule 4 to the Customs Tariff Act 1995).
It reduces or removes import duties for mining/refining companies, their importers and customs brokers, lowering the cost of maintaining, repairing or expanding alumina processing facilities. It took effect 30 August 2006 and remains until revoked.