EU probes long-term effects in BHP-Rio case-sources

LONDON, July 2 (Reuters) - Brussels regulators are taking the unusual step of looking at long-term effects of miner BHP Billiton's (BLT.L) (BHP.AX) $170 billion bid for rival Rio Tinto (RIO.L) (RIO.AX), according to people who have seen an EU questionnaire.

The Commission has gone well beyond the usual two or three years and is asking competitors and customers about effects of the deal on their businesses out to 2015, the sources told Reuters.

A European Commission spokesman had no comment, noting the Commission never comments on pending merger reviews. (Reporting by David Lawsky and Eric Onstad; Editing by Rory Channing)