BEIJING, June 22 (Xinhua) -- China's iron ore output expanded faster in May, official data showed. The country's iron ore output totaled 70.787 million tonnes last month, up 1.5 percent year on year, faster than the 1.2-percent growth in April, the National Bureau of Statistics (NBS) said. China saw shrinking output of refined copper in May, which fell by 5.2 percent to reach 711,000 tonnes. Output of aluminum oxide posted slower growth in May, up 0.1 percent year on year, compared with 4.2 percent in April. Growth of China's production of 10 major non-ferrous metals, including zinc, nickel and tin, slowed from April's 4.9 percent to 2.2 percent in May.