Rescue teams began their 10th day of searching for two trapped miners Thursday in southwestern Bulgaria, officials said. Ivan Lazarov, 35, and Nikolay Mihaylov, 42, remain trapped 1,470 feet below the surface under mud, rocks and water, Novonite.com said. Rescuers are excavating a detour passageway in an attempt to reach the two miners, but have only dug through 13 feet in the past 24 hours. Two other miners died in the collapse, which took place July 16. Union leaders have claimed poor safety standards caused the collapse, Novonite.com said. The incident was the fourth major accident at the Oranovo mine in the past eight years. The Economy and Energy Minister, Dragomir Stoynev, visited the site Wednesday morning. He said the government will investigate the incident and vowed to bring those responsible to justice, Novonite.com reported.