Iranian officials say they've recovered 22 bodies and the search continues.
An explosion on Wednesday at the Azad-Shahr coal mine in northeastern Golestan province left 35 people dead.
In a rare sign of public dissent, a group of coal miners attacked Iranian President Hassan Rouhani's vehicle on May 7 as he visited the site of an explosion that killed at least 35 miners.
He also said it is possible that one miner remains trapped inside the coal mine.
Several officials blamed the explosion on accumulated gas and said it was affecting rescue efforts.More news: Chinese fighter jets intercept United States aircraft
The miners pounded on and kicked the armored SUV carrying Rouhani in northern Golestan province, where the explosion occurred on May 3 at the Zemestanyourt mine.
President Hassan Rouhani visited the site on Sunday and afterward, angry coal miners kicked and beat his vehicle in protest but he was unharmed. He acknowledged that as the government, "we are responsible for their lives and is it our duty".
President Hassan Rouhani said on Sunday that those who are found guilty in a coal mine incident should face trial.
President Hassan Rouhani also expressed sorrow for victims of the disaster, which has overshadowed his re-election campaign. It uses about 2.5 million tons of coal annually, but only 1 million tons are taken out of its own mines.
Industrial accidents are common in Iran, where much of the infrastructure is outdated, according to The New York Times. However, many in the country remain discontent as the benefits of the nuclear deal have yet to trickle down to the average Iranian. In 2013, 11 workers were killed in two separate mining incidents. Delegations have visited Tehran from foreign countries, hopeful to receive the contracts.