* Union calls for walkout at Soma Mining sites
* Eight including CEO in custody over disaster
* Mine workers demand inspections at other sites
* Cabinet to discuss changes to mining laws (Adds Erdogan, energy minister, quotes from miners)
By Humeyra Pamuk
SOMA, Turkey, May 20 Several thousand workers stayed away on Tuesday from mines run by a company at the centre of Turkey's worst industrial disaster, with the main labour union demanding strict site inspections.
Three hundred and one miners died last week after a fire in a mine in Soma, a small town 480 km (300 miles) southwest of Istanbul, fuelling anger in a nation which has long had one of the world's worst workplace safety records.
Turkish authorities are holding eight suspects, including the head of the firm operating the mine, on provisional charges of "causing multiple deaths by negligence".
Soma Mining Chief Executive Can Gurkan was remanded in custody late on Monday, joining the mine's general manager and six others who are being held pending a formal indictment.
"We want the mining affairs directorate inspectors to carry out inspections and we will walk out until this has been done," Tamer Kucukgencay, regional head of the Maden-Is labour union, told reporters.
He said the action affected 3,200 mine workers in the town, where Soma Mining has three sites including the one hit by the fire. Monday was a public holiday in Turkey and miners had not yet returned to work.
Miners drifted around the town centre, many taking part in impromptu open forums, voicing complaints about poor working conditions and low pay as well as union shortcomings.
Some said they had been told by the mining company they did not need to return to work until the start of June. Nobody from the company was immediately available to comment.
Energy Minister Taner Yildiz told reporters in parliament that production had been halted at Soma Mining facilities until additional safety measures were taken. He said changes in Turkey's mining laws would be discussed at a regular cabinet meeting on Wednesday.
The disaster has sparked protests across Turkey, directed at mine operators accused of ignoring safety for profit, and at Prime Minister Tayyip Erdogan's government, seen as too close to industry bosses and insensitive in its response.
Erdogan vowed to pursue those responsible for the disaster.
"All administrative and criminal investigations will be conducted. Those who are responsible will be punished," he told deputies from his ruling AK Party in parliament.
Erdogan has presided over a decade of rapid economic growth in Turkey but safety standards have failed to keep pace, leaving it with one of the world's worst industrial accident records.
The main opposition Republican People's Party called for an inquiry into the role of Yildiz and Labour Minister Faruk Celik, whose ministries are responsible for regulating mines.
PRESSURE TO RETURN TO MINES
An initial report on the possible causes of the accident, cited by prosecutor Bekir Sahiner, indicated that the fire may have been triggered by coal heating up after making contact with the air, sending deadly carbon monoxide through the mine.
Workers in Soma voiced their concerns about returning to work in the mines but said that pressure to earn money and limited opportunities left little choice.
"I never want to enter a coal mine, never again. But I have a bank loan, credit card debt, two small kids," said underground crane operator Murat Yokus, 30, who was trapped in the mine for eight hours, four of them unconscious, before being rescued.
"If the money is underground, then we have to dig for it," he told Reuters, in the garden of his two-storey village house a few kilometres from the mine entrance.
Last Tuesday's disaster was Turkey's worst mining accident, surpassing the death toll of a firedamp explosion that killed 263 miners in the Black Sea mining town of Zonguldak in 1992.
According to the prosecutor's dossier on the investigation, cited by the Radikal newspaper, it was not until 57 minutes after the fire broke out that the fire brigade was notified and another six minutes before ambulance services were contacted.
Radikal said gas masks used by the miners were effective for only 45 minutes.
The plant manager has denied negligence at the mine, which has been inspected by state officials every six months. Alp Gurkan, chairman of parent company Soma Holding and father of the detained chief executive, said last week those responsible would be punished if an inquiry found evidence of negligence.
Thirty-six people gave statements to prosecutors over the accident, the prosecutor leading the case said late on Monday. Aside from the eight remanded in custody, the other suspects were released but could still face charges, court sources said. (Additional reporting by Ece Toksabay; Writing by Daren Butler; Editing by Nick Tattersall/Ruth Pitchford)