BUZZ-Petra Diamonds: issues new debt
** Diamond miner's shares extend recent falls, down c.2 pct after it issues new notes to service debt & expand its Cullinan operations
** Standard & Poor's rates new notes B+, citing volatility in rough diamond prices & prospect of negative FCF generation
** Stock among top losers on the FTSE 250 index, with more than half of its 30-day avg volume having gone through in the first hour of trade
** Shares (Berlin: DI6.BE - news) hit last wk when co warned on FY results (venkateshasoumithri.mamidipudi.thomsonreuters.com@reuters.net)