Anglesey Aluminium Metal Ltd, shut down on 30 September 2009, was a joint venture between Rio Tinto Group and Kaiser Aluminium. Its aluminium smelter, located on the outskirts of Holyhead, was one of the largest employers in North Wales, with 540 staff members, and began to produce aluminium in 1971. Until recently it produced up to 142,000 tonnes of aluminium every year and was the biggest single user of electricity (255 MW) in the United Kingdom.

Anglesey Aluminium is a metal smelting operation located on the Isle of Anglesey in Wales. The plant, which began operations in 1971, is the largest of its kind in Europe and is operated by Kaiser Aluminum, a subsidiary of the German-based ThyssenKrupp Group. The plant produces some of the world's highest quality aluminium, primarily for the automotive and aerospace industries. The plant is powered by two hydroelectric power stations, which are situated nearby, and is connected to the National Grid.

The Anglesey Aluminium plant is capable of producing up to 300,000 metric tons of aluminium each year. The process begins with the smelting of alumina, a compound of aluminium and oxygen, in a large furnace. The molten aluminium is then transferred to a casting house, where it is cast into ingots or slabs. The ingots are then rolled into sheets or extruded into rods, bars, and tubes, depending on the customer’s requirements. The finished products are then sent to the customers.

The Anglesey Aluminium plant is an important part of the local economy and employs over 1,000 people. The plant is also an important contributor to the local environment and has implemented a number of initiatives to reduce its carbon footprint and to improve the local air quality. The plant is also a major supplier of aluminium to the global market and is an important part of the UK's manufacturing sector.