Two Chinese companies are offering $650 million for Canadian miner Corriente Resources Ltd. in China"s latest bid to acquire resource assets abroad. China Railway Construction Corp. and Tongling Nonferrous Metals Group Holdings Co. announced the all-cash 679 million Canadian dollars ($650 million) offer Monday in a statement through the Hong Kong stock exchange. Corriente develops copper, gold, silver and molybdenum mines and its main assets are mining rights in southeastern Ecuador"s Corriente Copper Belt, according to the announcement. China"s state-owned mining and oil companies, flush with cash from its economic boom, are spending billions of dollar to acquire resource assets abroad in hopes of profiting from future demand. China Railway Construction is one of China"s biggest companies and raised $5.4 billion in a March 2008 initial public offering in Hong Kong. Tongling Nonferrous Metals is best known in China as a major copper producer.