BUZZ-Australia's BHP Billiton rises after China rate cut, upgrade
** Australia-listed shares in BHP Billiton Ltd rise as much as 2.5 pct
** China cuts interest rates for third time in six months
** Morningstar (NasdaqGS: MORN - news) upgrades stock to "Accumulate" from "Hold"
** The world's biggest miner recently approved Rapid Growth Project 6 that will increase installed Western Australian capacity to 245 mln tonnes per year by 2016
** Shares (Frankfurt: DI6.F - news) have risen 8.31 pct so far this year versus 4.24 pct rise in S&P/ASX 200 Index
** BHP most heavily traded stock on ASX 300 Metals & Mining Index (Reuters messaging: aparajita.saxena.thomsonreuters.com@reuters.net)