* Second stoppage on Sept. 29 coincides with general strike
* Protests have been under way for weeks
* Government expects EU approval for aid on Sept. 29
By Martin Roberts
MADRID, Sept 22 (Reuters) - Spanish miners began the first of two planned 48-hour strikes on Wednesday to demand unpaid wages and EU approval of a plan to let Spain favour domestic coal over imports as part of aid for the loss-making industry.
A spokesman for Spain's biggest union grouping, Comisiones Obreras, said all of the country's approximately 7,400 coal miners had heeded the strike call and that many were continuing protests that had been under way for weeks.
About one-third of the miners say they have not been paid for several weeks, and protest has simmered with miners blocking roads and holding underground sit-ins in mines.
Coal producers' group Carbunion declined to comment on the strike, but chairman Victorino Alonso said earlier this month that firms could not afford to pay miners because they had not sold any coal since February.
"In the summer we have brought forward all subsidies so that mining firms can pay payrolls," Industry Minister Miguel Sebastian told Spain's lower chamber of parliament.
The strike was called last week after talks broke down between the ministry and unions. A second strike is set for Sept. 29-30 and will coincide with a nationwide general strike, part of a wave of unrest expected in Europe this autumn.
AID PLAN
In February, the government passed a decree that will require utilities to burn domestic rather than imported coal, which is usually cheaper, but the plan has yet to be approved by the European Union's executive Commission.
Six miners who have been occupying the Industry Ministry began a hunger strike at midnight after hundreds of others began marches in the north and northwest of Spain on Tuesday to demand a future for coal mining.
"The march may be prolonged to Madrid in case the European Commission does not give the green light, on Wednesday 29 (September), to the government decree," a Comisiones statement said.
Sebastian told a Senate panel on Tuesday he was confident the decree would receive backing from a meeting of EU commissioners set for Sept. 29.
Commission documents have shown there are sharp divisions within the executive over Spain's arguments, one of which is that EU laws allow members to support domestic energy sources.
Coal is the only fossil fuel of which Spain has significant reserves and producers receive government subsidies.
Spain's competition watchdog has said the decree would distort the power market, and environmentalists say aid would be better spent on renewable energy, of which the country is a leading world producer. (Reporting by Martin Roberts, editing by Anthony Barker)