San Juan de Sabinas, Mexico ? Rescue workers searching for 65 coal miners trapped beneath the desert scrub of northern Mexico made excruciatingly slow progress Tuesday, working with picks and shovels as anguished relatives threatened to rush past soldiers guarding the pit.

More than two days after a gas explosion filled tunnels with fallen rock, wood and metal, rescuers have found no sign of the workers – either dead or alive – in the Pasta de Conchos mine, about 85 miles southwest of Eagle Pass, Texas.

Crews wearing gas masks and oxygen tanks got through one wall of debris, only to encounter another about 1,800 feet inside the tunnel early Tuesday. At least two conveyer belt operators may be just beyond the wall, but most of the other miners were thought to be as far as one to three miles from the mine’s entrance.

Because of fears that electric or gas-powered machinery could spark more explosions, rescuers have had to use picks and shovels to move tons of fallen dirt, rock, wood and metal.

A crowd of about 600 family members shouted at Coahuila state Civil Protection Director Arturo Vilchis until he took refuge behind a line of soldiers guarding the mine entrance.

“What are you hiding?” shouted one man. “If you don’t tell us the truth we will go into the mine ourselves.”

Other relatives begged for any information – no matter how bad. “Just tell us and get it over with,” said Maria Trinidad Cantu, who is awaiting word of her 32-year-old son, Raul Villasana.