* Plan revealed on eve of crucial WTO meeting
* EU takes middle ground on thorny sectoral issue
* Introduces "X" factor tariff cut plan for some products (adds details, background)
By Andrew Callus
GENEVA, April 28 (Reuters) - The European Union launched a bid to rescue stalled global free trade talks on Thursday with a compromise proposal on the main sticking point -- industrial tariffs.
The plan, a copy of which was obtained by Reuters on the eve of a key meeting of World Trade Organisation (WTO) members, aims to find some middle ground between the United States and major emerging economies, especially China.
Using the technical language and complex formulae of global trade, the two-and-a-half page plan focuses on tariffs for chemicals, machinery and electronics and seeks an approach that is tailored for each sector.
"Negotiations on sectoral tariff liberalisation are at this moment the biggest obstacle to an agreement in the Doha Round," the proposal said in a reference to the 10-year-old set of negotiations named after the Qatari capital where they began.
The Doha talks are the disarmament negotiations of the commercial world -- aiming to keep at bay the self-defeating spiral of tariffs, subsidies and quotas that can choke trade and, economists say, global prosperity.
U.S. Trade Representative Ron Kirk, speaking in Washington, said countries should give another push to finish the negotiations despite wide differences that have raised fears that the round is dead.
Traditionally, "sectoral" negotiations on industrial tariffs have aimed for a finishing point where no country charges any tariffs at all.
Under existing Doha proposals, developed countries like the United States are expected to deliver zero tariffs, while developing countries reduce tariffs under an agreed formula.
The United States argues that some developing countries, especially China, should do more, because in the decade since the talks began their exporting power has grown significantly. China says that Doha -- officially called the Doha Development Round -- was put together with just such growth in mind.
The EU has tended to sit between the two, though its interests are closely aligned to those of the United States.
The EU proposal would add a negotiated "X" factor to developing country tariffs cuts in some product areas in a bid to shift the balance some way towards the U.S. position, while keeping a certain level of protection for developing countries.
In others -- electronics and electrical machinery for example -- where developing countries dominate the export market, some developing countries would be expected to eliminate tariffs completely.
"Modalities and product baskets cannot be the same for all sectors as trading interests and conditions differ per sector, but arrangements should not be overcomplicated. The simpler the modality, the higher the chance of success," the EU proposal said.
The EU's plan was circulated among trade missions on Thursday and presented to an informal meeting of representative nations called to prepare for Friday's Trade Negotiations Committee session which oversees Doha discussions.
An EU official declined to comment. (additional reporting by Doug Palmer in Washington; dditing by Stephanie Nebehay and Tim Pearce)