Investigators have pulled 56 corpses and four heads from the 600-foot-deep mine shaft on the edge of this town, nestled in the verdant mountains 110 miles south of Mexico City.

Many of the victims were dumped into the slanted chute while still alive and aware.

"The rocks in the shaft are sharp-edged and tore at the bodies," Luis Rivera, 23, Guerrero state's senior criminologist in Taxco, said in explaining the feet, hands and legs torn from some victims. "There were some who arrived alive at the bottom."

Only eight of the badly decomposed bodies have been identified so far, including that of a prison warden kidnapped in late May. But police say all the victims were killed by the henchmen of a Texas-born gangster, Edgar Valdez, who is warring for control of one of Mexico's largest drug-trafficking organizations.

Not long ago, such a gruesome discovery would have been headline news for weeks in Mexico. But the atrocities linked to the country's gangland wars come too fast these days for any to draw notice for long.

Shootouts no longer shock. Beheadings have become boring and massacres mundane. Unearthed narco-graves — the clandestine mass tombs where many drug war victims lie - now serve merely as mileposts.

More than 400 people this year have been killed gangland style in Guerrero state, which includes Taxco, as Valdez's group fights with his rivals for smuggling routes and local markets. Amid that fighting, men have been disappearing by the dozens in Taxco and surrounding towns.

'Count the heads'

There were rumors that some of those who vanished had been dumped down the ventilation tunnel of the mine, which like most others nearby has been closed for three years by a labor strike.

The vent sits alongside a badly rutted road that overlooks a valley of grazing livestock and farm fields a few miles from town. A 465-year-old hacienda, which was the first silver processing plant in Mexico and now hosts a New Age wellness retreat, sits half a mile away.

Precisely to keep people from falling into the shaft, the mining company years ago had it enclosed by tall cinder- block walls topped with closely spaced iron beams. But someone had removed some of the blocks, leaving a small breach in one wall.

People used to throw trash and sometimes dead animals into the pit through that gap, one local resident said. Gangsters dispatched their victims the same way.

Investigators had responded to past rumors by searching the upper reaches of the vent, finding nothing. They were sent in again on May 29 after captured gangsters told army interrogators that they recently had dumped three men into the hole.

Rivera, the state criminologist, got the call before dawn that Saturday morning. He sent an underling into the mine, who called by late morning to report there were "many bodies" in a large pit at the foot of the shaft.

The number of victims wasn't easy to calculate, the man told Rivera, because there also were many unattached limbs.

"I told him to count the heads," Rivera said in a hushed voice. "I knew I would have a lot of work."

Rivera informed his superiors of the discovery and was told to retrieve the mangled remains by any means necessary, despite a lack of proper rescue equipment. Rounding up local firefighters and police officers for the task, Rivera reluctantly decided he had to go down into the mine himself.

Climbing into his office's single disposable biohazard suit, Rivera descended on a rusted ladder for the first 11 yards or so, then rappelled the rest of the way down.

Once on the bottom, Rivera said, he stumbled over something and stepped into a tangled heap of decaying flesh. It felt like quicksand, he said, the dead floating in a thickened broth of water and the fluids from their decomposing remains.

Bodies stacked deep

Rivera had assumed the pit was no more than a foot or two deep. But when he tried to gauge it with a 5-foot board, he couldn't touch bottom. The team then realized that the floating bodies were stacked several deep. As one was pulled out, another would surface.

Working in the dank, dark cavern, Rivera and the other men began pulling bodies from the pit. They lifted the victims in their arms, wrapped them in burlap sacks and looped ropes around them. Others at the surface pulled the bodies up by hand.

The crews managed to retrieve only four victims in the first 24 hours. It took six days to remove them all.

Rivera said that scabs on some of the bodies suggested their hearts were still beating when they were plunged into the mine's maw, the rocks and jutting metal bars biting into them like fangs.

"Many were thrown in alive," the criminologist said.

People have been coming to Rivera's office and to morgues all month, searching for family members who have gone missing. They bring face shots, descriptions of tattoos and birthmarks, lists of clothes the missing were wearing when last seen.

Many to remain nameless

Investigators positively identified one of the men by a leg that bore a tattoo of the Virgin of Guadalupe and another proclaiming "Made in Mexico." Another reclaimed his name because "Rosa" was inked into his chest.

But most of the bodies are decayed almost beyond recognition as human. A few had become mummified, Rivera said. The cold and humid conditions of the mine - and its lack of insects and foraging wild animals - make establishing any time of death difficult, he said.

So Rivera can offer little hope to most of the searching relatives. But he'll keep trying.

"These might have been bad people," Rivera said of the victims. "But their families are not at fault. They need to know."

dudley.althaus@chron.com