This mining accident was a by product of an underground fire that burned in the United Verde Mine from 1894 until 1916. Here is the newspaper account of the accident:

CAVE-IN AT UNITED VERDE MINE CAUSES EXPLOSION AND DEATH.
Five Miners Killed By Blast Of Hot Gas, Air and Steam--Several Others Injured.

KILLED

T.W. Crawford-----Peter Serder-----Leroy Duffin
Joe Wilovitch-----Nick Lazovitch

SERIOUSLY INJURED

M.J. Sullivan-----A.J. Holman

BADLY INJURED

John Kostic-----J.D. Rose-----J.W. Rose
Barni Karaza-----B. Garcia

Five miners killed and seven others badly injured was the tragic result of an explosion which took place on the 300-foot level of the United Verde mine at Jerome Sunday morning between 3 and 4 o'clock.
Twelve miners, the last of the shift to leave the stope, were standing at the station waiting for the cage to take them up when there was a roar, a hiss and a loud report.
Four of the men were killed almost instantly, a fifth died a few hours after being taken out, and seven others sustained injuries, one of whom is expected to die, while three others have only a small chance of recovery.
The death of the five men was investigated in Jerome yesterday afternoon by a coroner's jury composed of R. A. Armstrong, foreman; H. P. Merrill, W. S. Adams, Thomas Kelly, Charles Hooker, Dan Bean, W. S. Owens and George Avery. Justice L. B. St. James conducted the proceeding.
The five men killed in the mine were T. W. Crawford, Peter Serder, Leroy Duffin, Joe Wilovich and Nick Lazovich, and it was the duty for the coroner's jury to determine whether or not blame could be fixed for their terrible end.
The verdict of the jury was that in the case of each man "Death was caused from external and internal injuries from hot gas, air and steam, driven against his body and inhaled into his lungs from a burning stope which caved in from the surface in the United Verde mine a short time before his death. The cave-in was an unavoidable and unforeseen accident for which no blame can be attached to the United Verde Copper Company.
This verdict exonerates the United Verde from all blame. It was reached after several witnesses had been examined, none of whom could do more than theorize as to the causes which led up to the explosion. When news of the accident first reached Prescott it was reported that rain water had reached the burning copper ore, and the result had been the generating of steam that finally blew out bulkheads, built a few years ago to prevent the fire in the mine from spreading.
It now appears that the accident is due to another cause. From Jerome last night came the plausible theory that ground from the surface had caved as a result of the fire burning out the ore, and that this cave had forced gas, steam and hot air into a small space just behind the bulkhead. Under great pressure the barrier gave way, it being about four by six feet. Unfortunately for the four miners they were directly in front of it.
Half an hour after the catastrophe men from the surface were at work repairing the damage done, and in a short time had another bulkhead constructed that completely shut in the fire, and prevented its spreading to other parts of the mine.
There is now absolutely no danger of any serious results. With the fire within its proper bounds the mine will continue to operate the same in the future as it has in the past.
The most serious damage sustained by the company is the ground that has sunk from the surface to the 300 foot level. Underneath the railroad tracks between the smelter and the hill there is a depression of twenty five feet. It has been necessary to bridge this over with timbers so that trains can pass. Though no one saw it, those who have investigated believe that this cave took place possibly a few hours previous to the explosion.
The sunken space is about thirty-five feet in diameter. It shows no sign of further depression. From appearances, the twenty-five feet is just the distance that had been burned out at the 300 level.
For six years or more the United Verde has expended large sums of money in fighting this fire, which has threatened at times to spread to all parts of the mine. By a series of bulkheads and thick cement walls they have managed to keep it within bounds.
Owing to the large amount of sulphur in the copper ores it burns readily when once started. After a certain temperature is reached the fire keeps melting ore ahead of it in sufficient quantities to constantly have enough fuel in the form of sulphur.
Some parts of the mine are so hot that men work there with great difficulty. Hundreds of good miners have attempted to work in these stopes and drifts, only to find it impossible."
The men killed and injured Sunday morning had been working not far from the bulkhead that blew out before they started to leave the mine. With them a few minutes earlier were almost a hundred men, who might have been killed had the accident happened at any other time than just when the change in shift was being made.
The bodies of Crawford, Serder, Wilovich and Lazovich will be buried in Jerome this afternoon at 2:30 o'clock. The remains of Duffin will be shipped to Toquerville, Utah.
Though three of the men killed were foreigners, and but little known in Jerome, the terrible accident caused much sincere regret. Crawford and Duffin were both Americans, who had many friends.
Dr. Woods, chief of the United Verde medical staff, now has two physicians in Jerome assisting him at the company hospital, where the seven injured men are being cared for. Their names are: A. J. Holman, M. J. Sullivan, John Kostle, J. D. Rose, J. M. Rose, John and Barni Caraza.
All of these men are badly scalded and burned. Sullivan and Holmes are both said to be in a most serious condition. It will be impossible until later to determine for certain the chance they have to recover.

--Weekly Journal-Miner (Prescott, Arizona)
April 5, 1905 (Wednesday)
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Other miners who died as a result of the accident:

T.W.Crawford

Peter Serder

Nick Lazovich

Eugene Roy Duffin

*Note: Leroy Duffin is Eugene Roy Duffin (linked here). He is buried in Utah, and is on the Utah Death Register list which states that he did die in a mine explosion in Jerome, Arizona.