Shares in Minmetals Resources, the mainland's largest alumina importer, plunged 9 per cent yesterday after the company reported a 22 per cent slump in first-half profit as the price of alumina and imports of the material fell on rising domestic supply. Net profit at the Hong Kong-listed alumina trading unit of China Minmetals Corp dropped 22.24 per cent to HK$451 million from a year earlier. In the first half, sales fell 27 per cent to HK$4.98 billion. The company declared an interim dividend of 0.5 HK cents a share. Alumina trading revenue declined 51 per cent to HK$2.7 billion, accounting for 50 per cent of the company's first-half turnover. During the period, alumina sales volume was halved to 543,000 tonnes from 1.04 million tonnes a year earlier while the average selling price per tonne fell 21 per cent, dragging down overall gross margin by 3.8 percentage points to 11.3 per cent. To reduce its reliance on imported alumina, Minmetals Resources said it would speed up the long-awaited acquisition of its parent's 33 per cent stake in Guangxi Huayin Aluminium, an alumina refinery with annual production capacity of 1.6 million tonnes. Initial studies on plans to set up a joint venture with Nasdaq-listed aluminium producer Century Aluminium to develop bauxite mining and to build a 1.5 million tonne a year alumina refinery in Jamaica are expected to be available by year-end. Shares of Minmetals Resources closed at HK$4.37 yesterday, down 8.96 per cent, after it announced its first-half results at noon. The stock has surged 35 per cent in the past three months. Meanwhile, the parent firm said it would seek more copper resources overseas to tap rising demand from the fast-growing domestic market and source iron ore and tungsten deposits in the mainland, Bloomberg reported, citing Minmetals Corp senior vice-president Song Yufang as saying at a conference in Dalian yesterday. Mr Song did not give any details.