Fourteen-year-old Frank Hrvatin had quit school to work in one of Minnesota's mines. That wasn't unusual in 1924 for the son of Croatian immigrants.

But the hot blast of wind was unusual. It was supposed to be cool and still down where Frank was shoveling manganese ore — 175 feet down the Milford Mine that Feb. 5 afternoon.

The gust of warm air snuffed out the carbide gas light on the teenager's helmet. Then Frank noticed water and mud oozing in, covering his boots. Running and stumbling 600 feet through a dark horizontal tunnel, Frank reached the mine's one vertical shaft and began to scurry up the ladder.

With water climbing fast, Frank wormed around an older miner, Harry Hosford. But another exhausted miner, Matt Kangas, clogged their escape route.

Frank would later recall the "superhuman strength" that took over and enabled him to squirm between Kangas' legs and hoist the man rung-by-rung up to safety. Then he reached back down and grabbed the wrist of Hosford, who was up to his waist in rising muck, hollering: "For God's sakes, hurry!"

The three miners were among the only seven who got out when a surface cave-in caused water to flood the mine from nearby Foley Lake a few miles north of Crosby. In a deadly 15-minute span, the lake ice cracked and the water level dropped as it filled the mine tunnels and shaft to within 15 feet of its collar.

Forty-one other miners, including blaster Frank Hrvatin Sr. — the teenager's dad — drowned or were crushed in the state's worst mining disaster. The last body wasn't recovered for nine months. The tragedy left 38 widows and 80 fatherless children in the mining settlements near Crosby — a town named after the mine's owner, George H. Crosby.

The men were digging for manganese ore — known, fittingly, by its chemical symbol Mn — a key component in forging steel. Since it opened in 1918, the Milford Mine had been hauling between 70,000 and 100,000 tons of ore by the bucket load to waiting trains up top along the Cuyuna Range — one of the four ranges that collectively make up the Iron Range.

The year before the disaster, the mine's depth reached 200 feet and it employed dozens of immigrants from Finland, Germany, Austria and Yugoslavia — the kingdom that included Croatia, the Hrvatins' ancestral home.

More than 50 years after the tragic mine flood, Frank Hrvatin Jr. lay in a Seattle hospital in 1976. He was 67 and would soon die from the scourge of miners, lung disease. But first, he agreed to an interview with researchers from the Iron Range Interpretive Center in Chisholm, the highlights of which were reprinted in a 2006 series on the disaster by Connie Pettersen of the Brainerd Newshopper.

"They wanted that ore real bad," Hrvatin said. "In those days they needed steel … every place they could get it. After the armistice [ending World War I on Nov. 11, 1918], they had to replace supplies because steel was gone. With the first world war, we practically supplied everybody with steel and iron."

Frank's father had told him they wouldn't be mining there much longer because the so-called drifts shooting out horizontally from the main shaft were so close to Foley Lake.

"They were under the lake," Frank Jr. said. "Directly under the lake. The mining engineer told the company many times about the danger, but they wouldn't listen. They just wanted that ore."

Investigators, appointed by the governor, interviewed hundreds of witnesses and ultimately declared the disaster an act of God with no one to blame.

But in his book "The Milford Mine Disaster," the late author Berger Aulie says miners were afraid to criticize the company, fearing it would jeopardize their livelihoods. Mines with one way in or out were considered extra dangerous if not illegal.

In what he called a frenzy to extract manganese, Aulie asked: "Were safety functions overlooked? Was the mine encroaching on Foley [Lake] property? Was it operating under the lake? The investigating committee reported to the contrary. … Draw your own conclusions."

Frank Hrvatin Jr., at 67, drew his own conclusions. "That farce they called an investigation? They went in immediately and got their stories all conflicted, and it was 'an act of God' — nobody at fault," Hrvatin said. "And how does a small person without any funds fight a guy with a lot of money or a group with a lot of money? It's absolutely impossible. So they made it stick and that's the way it was written off."

Frank waited for hours by the silt-packed shaft opening on Feb. 5, 1924 — knowing his father was buried below, afraid to go home and break the news to his mother.

Another of the 41 men entombed in the mine that day was Clinton Harris from the tiny town of St. Mathias, between Brainerd and Little Falls. He was serving as skip tender, overseeing the carloads of ore dumped into buckets and hoisted electrically up the 200-foot shaft. He died at the foot of the ladder, apparently choosing to stay at his position, yanking his whistle cord that blasted an alarm, alerting other miners.

That siren wailed for nearly five hours, from the 3:30 p.m. cave-in to long past dark when the mine was all but filled with silt and muck. It's unclear whether Harris got tangled in the whistle cord or tied it to his belt on purpose to ensure the alarm would continue to sound.

Workers in the engine room on the surface finally disconnected the line to the whistle. And an eerie quiet returned to the Milford Mine.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com