Top executives at mining behemoths BHP Billiton (BHP.NYSE) and Rio Tinto (RIO.NYSE) said they believe demand for iron ore from China’s manufacturing sector will remain substantial even as the price of the steelmaking ingredient reached new depths following Beijing’s announcement of a lowered growth target, The Wall Street Journal reported. BHP iron-ore president Jimmy Wilson said demand from manufacturing was running above expectations in recent months while the cooling property market could be set for an uptick; Rio Tinto iron-ore chief executive Andrew Harding expressed optimism in a speech on Tuesday.