U.S. mining equipment maker Joy Global Inc said on Friday it bought 10.5 percent of China's International Mining Machinery Holdings Ltd (IMM) for about $140 million in the open market.

Joy Global said the 136.5 million shares it bought adds to the 41 percent it had agreed to buy earlier this month for $585 million.

The company had then said it would be required to make an offer for the remaining 59 percent of IMM once the share purchase agreement was completed.

Joy Global is investing in IMM, which makes underground coal mining machinery, to expand in China's fast-growing coal market.

It had agreed to buy the initial shares -- about 535 million -- at HK$8.50 a share. On Friday, it said it acquired the additional IMM shares for HK$8 a share. (Reuters)