5.5 km of the McArthur River. The mine's expansion was quickly approved, with the support of Prime Minister John Howard. The approval was later revoked by action taken by the Northern Land Council with the support of the traditional owners and the Environmental Defenders Office, through the Supreme Court of the Northern Territory. This decision was also overturned within days and the mine given the go-ahead once more by parliamentary vote. The traditional owners continued to protest, taking the matter to the Federal Court of Australia. They won the case, only to have this decision declared invalid. The final decision was left to Peter Garrett, the Federal Environmental Minister at the time. Xstrata had threatened to sack all 170 staff unless Garrett made a quick decision. On 22 January 2009 he approved the expansion, "subject to a further 10 days of evaluation by Indigenous groups and others", promising also to protect local species such as the sawfish and migratory birds. Later in 2009, a report found that the mine's environmental impact was not being monitored. In 2012 mining giant Glencore bought the remaining 66% share in Xstrata, taking over the McArthur River Mine. In 2013, the Northern Territory Government approved another $360 million expansion that would double its size and production, extending the life of the mine to 2038. Following an environmental impact study, the expansion is expected to increase production to 5.5 million tonnes per year and increase the workforce to 735 by 2020. It will extend the mine's life until 2038 and is projected to contribute $8.4 billion to the Northern Territory economy and $9.3 billion nationally. Operation The HYC deposit covers around and area of about two square kilometres and is 55 m in depth. Approximately 2.5 million tonnes of ore containing 383 kt of zinc, 93 kt of lead and 110 t of silver are currently mined per year, supplying markets in Europe, Japan and China. Bulk concentrate is refined to make zinc and lead metal and alloys. Ore processing The HYC ore body consists of an extremely fine dissemination of the valuable mineral grains intermeshed with the gangue. The technology to efficiently produce a marketable concentrate from this type of ore was not available until long after the deposit was identified. After Mount Isa Mines successfully introduced the IsaMill, the fine grinding necessary for mineral liberation was available for McArthur River to be developed. This