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Mine Disasters in the United States

Magma Copper Company
Magma Mine Cave-in

Superior, Pinal County, Arizona
May 10, 1982
No. Killed - 3

Fatal Accident Investigation Report  PDF Format

See also:   Magma Mine Fire, Nov. 24, 1927
  Magma Mine Falling Material Accident, Aug. 10, 1993

Successful Rescue and Rescuer Deaths

Three miners died between 5:30 and 6 p.m., on May 10, 1982 in three separate incidents that involved a cave-in and fall-of-ground in the Magma Copper Mine in Superior, Arizona.  During a daring rescue and recovery which lasted through May 12th, one of the victims was recovered from the dangerous area, however, he died shortly thereafter from his injuries.  Joseph Granillo was also entrapped in the same manner, and while his rescue was being attempted, both he and his would-be rescuer, Joseph Cassaro, were killed when additional material fell.  For their brave efforts, the Carnegie Hero Award was bestowed upon Frank Aldecoa, Andy J. Arroyos, Jr., Billy Ray Evans, Henry Lopez Rodriguez, George Anthony Gomez, G. Michael Martinez (posthumously), and Joseph Cassaro (posthumously).  Source documentExternal Link

Joseph N. Cassaro, underground mine supervisor, age 46; George M. Martinez, stope miner, age 39; and Joseph Granillo, stope miner, age 26, were fatally injured between 5:30 and 6 p.m., May 10, 1982 in three separate incidents that involved a cave-in and fall-of-ground in the farm area of the 3440-2C stope.

The three were employees of Magma Copper Company, Superior Division for a combined total of 13 years.  Cassaro's total known experience was 8 years, and was with this operation for about 3 years and a supervisor since December of 1979.  Martinez's total known experience was 12 years and was with this operation for over 2 years as a stope miner.  Granillo's total known experience was 8 years, all at this operation and was a stope miner for 2 years.

The Phoenix, Arizona Subdistrict Office of the Mine Safety and Health Administration was notified of the accident about 6:30 p.m., May 10, 1982, by Norbert Barajas, company safety engineer.  An investigation was started the same day.

Information contained in this report was obtained from company officials, one victim's working partner, additional employees, and examination of the accident site.

An MSHA approved training plan was in effect and in compliance with Part 48 of 30 CFR.  The victims had completed their last annual refresher training on November 3, 4, and 6, 1981.

Description of the Accident

On the day of the accident, George M. Martinez, miner (victim); Joseph C. Granillo, miner (victim); Joseph N. Cassaro, supervisor (victim); reported for work on their regular afternoon shift, 4 p.m. to 12 midnight.

Reportedly, a safety meeting was held, and conducted by Cassaro (victim), on the 3400 level with numerous employees which included the other two victims.

After the meeting George A. Gomez and Granillo (victim) proceeded to their working place, 3440-2C stope.  They instructed the timber rustlers to stay near the stope's timber slide at the level, while Granillo and Gomez checked on what timbers they were going to need.  After returning with their timber order, Gomez and Granillo sat down near the stope's entrance, drank a soft drink, smoked a cigarette and discussed the timbering process.  They were to finish timbering by standing two posts under the middle set and blocking and lagging the west and face sides.

At about 5:30 p.m., Gomez and Granillo went back into the stope and stood on the farm pony set floor.  Seeing some loose ground, Granillo asked Gomez for a bar.  As Gomez handed Granillo the bar, the first fall-of-ground occurred.  Gomez jumped back into the 6th pony set of the panel, getting away from the cave-in.

Gomez stated the ground or timber gave no warning whatsoever.  When the dust had cleared, Gomez saw that the farm pony set, the 7th, 8th and 9th sets of the 17 N panel were washed out.  He saw Granillo trapped up to his waist and was not able to pull him out.  He immediately ran for help to the adjacent 3440-SC stope, some 200 feet away.  Andy Arroyos (witness) miner; Paul Gonzales (witness) miner; Martinez and Cassaro (victims) responded to Gomez's call.

Arriving at the accident site, the five men began trying to rescue Granillo.  Cassaro ordered Gonzales up the level (3400) to summon help and get a basket.  At this time, Arroyos asked Martinez to help him remove a steel beam that was next to Granillo.  When doing so, a second fall-of-ground occurred hitting Martinez and knocking Arroyos to one side.  Gomez and Arroyos picked up Martinez and laid him in the middle of the first farm set, which was still standing.  Gomez then left to assist Gonzales.

Arroyos helped Martinez into a comfortable position.  Seeing the ground was moving over and around the existing farm set, he decided to move Martinez, who was still alive and talking, into the panel's 11th middle set.  Arroyos stated that, when the events were happening, Cassaro was digging, trying to uncover Granillo.  Arroyos also stated that after assistinp, Martinez, he told Granillo to grab hold around his neck and Arroyos, putting his arms around Granillo's upper body, tried to pull him out, but to no avail.  Seeing that Granillo's legs were pinned between timbers and muck, he decided to run back to his stope for a tugger, to pull the timbers from around Granillo.

Help had been summoned and a basket had been lowered down the stope's timber slide and manway.  Gomez then returned to the accident site carrying the basket.  He stated that he saw Cassaro and told him he had the basket when the third fall-of-ground occurred, completely covering Granillo and Cassaro.  As the dust cleared, he yelled for anyone and Martinez was the only one that responded to his call.

More help arrived, and with the roof still caving, three miners, Henry Rodriguez, Ray Curtis, and Andy Arroyos, crawled over the muck pile and were able to load Martinez onto the basket.  Martinez was taken to Number 9 mine shaft where he was pronounced dead.

Rescue and recovery continued around-the-clock.  Granillo's body was recovered at 1 a.m. and Cassaro's body was recovered at 5 a.m., on May 12, 1982.

On May 4, 1982, blasting was conducted in the Magma Mine, an underground copper mine.  Distracted by deteriorating tramway conditions, miners failed to quickly follow-up this blasting with timbering.

As a result of this delay, ground control problems were encountered on May 10.  At about 2:40 a.m., as two miners were responding to these problems by barring down some loose ground near timbers, a cave-in suddenly occurred without warning.  One of the miners was trapped in the collapse.

After unsuccessfully attempting to free the trapped miner, the other miner summoned three miners who were working in an adjacent area.  Their rescue attempts went awry when one of the rescuers removed a steel bar near the trapped miner, triggering a second cave-in.  This collapse fatally injured another miner.

Shortly thereafter, a third cave-in occurred.  This collapse killed the trapped miner as well as a fourth individual.  MSHA investigators attributed the disaster to the failure of temporary ground support.  The lag time between blasting and the installation of permanent ground supports also contributed to the disaster.

Historical Summary of Mine Disasters in the United States - Volume I

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