Task: Explanation
Input (English): Australian Railroad Group (ARG) was an Australian rail freight operator. It began operations in Western Australia on 17 December 2000 following its purchase of the Westrail freight business. It was purchased by QR National in June 2006. The main commodities hauled by ARG included grain, mineral sands, alumina, bauxite, coal, woodchips, quartz, nickel and iron ore around Western Australia. In June 2011 it ceased trading as a separate brand, and became part of QR National. Question: When did the Australian rail freight operator, whose main commodities included Aluminium oxide, become part of QR National? Answer: June 2011
Output (English):  In June 2011 it ceased trading as a separate brand, and became part of QR National.