UPDATE 2-Tata Steel Europe workers question rationale of Thyssenkrupp tie-up

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LONDON/FRANKFURT, June 11 (Reuters) - Tata Steel's European labour representatives remain unconvinced by a planned joint venture with Thyssenkrupp, adding there are numerous details that need to be hammered out before they can endorse a deal.

The remarks on Monday by Tata Steel Europe's European Works Council (EWC) threaten a further delay to a deal to combine Thyssenkrupp's steel operations with Tata's European steel business, a pact which has not been signed because of resistance from Dutch workers.

"The EWC acknowledges there is an industrial rationale for pursuing this JV, but with the matters outstanding the EWC remains unconvinced that this partnership with Thyssenkrupp would be in the best interests of Tata Steel Europe's operations and the employees we represent," it said in a statement.

Thyssenkrupp said in May it expected to be able to sign the deal with Tata Steel, agreed in principle last September, in the first half of 2018. Tata Steel confirmed that timeline at the time.

The planned transaction would combine Thyssenkrupp's and Tata Steel's European steel operations to create the continent's second-largest steelmaker after ArcelorMittal with sales of 15 billion euros ($17.7 billion).

The EWC said Thyssenkrupp had been unwilling to engage and help its advisers understand the German firm's aspirations and plans with regards to the join venture, adding the financial structure of the deal remained a "work in progress".

A Tata Steel spokesman told Reuters: "We will continue to engage in constructive dialogue with our employee representatives throughout the process of creating the proposed joint venture."

He added Tata Steel was committed to delivering the joint venture without the need for compulsory redundancies.

Tata's Dutch works council said in April it still had "major reservations" over the joint venture, even though Tata promised limited job losses and an independent position for the Dutch operations within the new company.

The comments followed a preliminary deal reached between Tata and the Dutch unions in March, in which Tata promised no forced redundancies until 2026 and job losses limited to 300-400 supporting functions.

The EWC, which oversees all the Tata Steel Europe trade unions, said its advisers had recommended it oppose the current business plan because it prioritises shareholder dividends over the long-term development of the join venture.

Thyssenkrupp was not immediately available to comment. Two people familiar with the matter told Reuters the German firm's supervisory board would meet on Wednesday and would likely discuss the joint venture.

The EWC said its support for the joint venture depended on factors like a moratorium on jobs reductions until 2022 and no Tata Steel site closures before 2026. It also wants the sale of Tata's electrical steel subsidiary Cogent put on hold.

The planned European steel joint venture marks the core of Thyssenkrupp's strategy shift away from steel. (Reporting by Maytaal Angel and Christoph Steitz. Additional reporting by Tom Kackenhoff; Editing by Edmund Blair and Mark Potter)