Hopes of saving 15 miners trapped deep underground in a Polish coal mine faded on Wednesday (November 22) as rising gas levels and flooding forced a temporary break in rescue efforts. More than 50 emergency workers dug through 500 metres of rubble overnight to try to save the miners stuck in a shaft about 1 km beneath the town of Ruda Slaska, 300 km (190 miles) southwest of the capital of Warsaw, after a gas explosion on Tuesday (November 21). At least eight other miners were killed by the blast. Emergency workers detected dangerous methane levels in the Halemba mine's shaft and said the blast may have damaged a pump, flooding the area and leaving little hope that anybody could still be found alive. President Lech Kaczynski arrived at the disaster site on Wednesday after calling off planned visits to Georgia and Romania. "We need to have a glimmer of hope. Although I can confirm eight casualties, I cant hide the fact the the situation is very bad." he said on a news conference "We are doing everything to ensure that the most urgent assistance will be delivered to all of the families, even those who formally aren't miners. Especially in those cases when the deceased is the father and the main supporter of the family." Kaczynski told reporters. The president's twin brother, Prime Minister Jaroslaw Kaczynski, also flew to the mine to watch rescue efforts and promised help for the families of the miners who gathered around the pit awaiting news of their loved ones. The prime minister has declared a period of national mourning for the eight dead miners. Officials said temperatures in the mine, very deep and considered exceptionally dangerous, may have reached as high as 1,000 degrees Celsius at the time of the blast. The Halemba mine is one of the oldest in Poland and has been in operation since 1957. It lies at the heart of the Silesia region's industrial belt that has been the scene of several disasters in the past. In 1990, 19 miners were killed in the same pit by a gas explosion. Poland's state-run mining industry, built up before the fall of communism in 1989 but starved of investment for years, has seen hundreds of deaths over the last few decades and its safety record has been among the worst in Europe.