China Guangdong Nuclear Power Holding Co., or CGNPH, Tuesday offered 83.6 million Australian dollars (US$71.6 million) for control of Energy Metals Ltd., adding to a wave of Chinese investment in Australia's natural resources.

State-owned CGNPH's offer to buy 70% of the operator of the proposed Bigrlyi uranium project in Australia's Northern Territory also signals China's first significant corporate move into one of the world's biggest uranium producing nations.

The offer comes amid a low point in relations between China and Australia following the detainment last month of four employees of Anglo-Australian mining giant Rio Tinto Ltd., including Australian citizen Stern Hu, on charges of bribery and infringing on state secrets. It also comes as disquiet grows among some politicians and commentators about the amount of Chinese investment in Australia's mining sector.

Also Tuesday, China Railways Materials Commercial Corp. proposed to take substantial stakes of around 12% in two Australian iron ore juniors, United Minerals Ltd. and FerrAus Ltd.

China already has an indirect investment in Australia's uranium sector through Aluminium Corp. of China's 9.3% shareholding in Rio Tinto. And in 2006, the former Liberal-National coalition government allowed China's Sinosteel to take a 60% stake in a uranium project to be supplied by local miner PepinNini Minerals Ltd. The joint venture is still targeting production from a project in South Australia state in 2011.

Perth-based Energy Metals has a portfolio of eight undeveloped uranium properties covering 4,000 square kilometers in Australia's Northern Territory and Western Australia state.

CGNPC is offering Energy Metals A$1.02 a share cash, an 18.6% premium to its latest price of 86 cents before trading in the shares was halted on Aug. 27. CGNPC has also agreed to underwrite an A$11.7 million 1-for-9 rights issue at 90 cents a share. It will end up with 73% of the company if no other shareholders participate.

The offer is subject to the approval of shareholders and Australian and Chinese regulators.

The Australian Foreign Investment Review Board is also mulling a proposed A$3.54 billion acquisition of coal miner Felix Resources Ltd. by China's Yanzhou Coal Mining Co. and a controversial A$252 million investment by a Chinese company in Lynas Corp. that would strengthen China's hold on the world's supply of rare-earth minerals.

The proposed Energy Metals deal is substantially smaller than others being considered by FIRB, so it's unlikely to attract the same level of regulatory scrutiny. It also involves a small portion of Australia's uranium resource.

Chinese interest in Energy Metals is of little surprise as China strives to increase its use of cleaner-burning fuels. The country is considering doubling its target for nuclear power generation by 2020 to 86 gigawatts, from the current goal of 40 GW, according to state media. However, China's known uranium reserves are insufficient to meet this expansion.

Tuesday's move by CGNPC signals that China is intensifying its drive to lock up uranium resources via takeover offers for listed companies, rather than government-to-government deals as in the past.

The proposed Bigrlyi project, which is 54%-owned by Energy Metals and 42% owned by Paladin Energy is in scoping study phase, an Energy Metals spokesman said.

An official from CGNPC unit China Uranium Development Co., which is making the offer for Energy Metals, declined to comment.

The China Railways Materials deals also require Australian government approval.