A fall-of-ground accident at the Homestake Mine - Ross Shaft, Homestake Mining Company, Lead, Lawrence County, South Dakota, resulted in the deaths of three underground employees. A fourth man in the stope at the time escaped injury.
The accident occurred at approximately 8 p.m., March 21, 1972, in 32-33 D Stope, 19 Ledge, 5900 Level.
The Homestake Mine - Ross Shaft, an underground gold operation, was located within the city limits of Lead, Lawrence County, South Dakota. The mine was owned and operated by the Homestake Mining Company.
The mine was opened by two ore production shafts. Ore was mined using the cut-and-fill and square-set stoping methods. Integrated operations of mining, milling, and smelting were conducted on the property.
A total of 1839 men was employed at the property, 1030 of whom worked in the mining department. The mine was operated during two 8-hour production shifts a day, 6 days a week. The last health and safety inspection was completed
on March 15, 1972.
Description of Accident
On the day of the accident, Harry J. Kinney and Gary L. Schamber, both miners, began work at the usual time of 6 p.m. The two miners were assigned to work in 32-33 D cut-and-fill Stope, 19 Ledge, 5900 Level. During the previous shift, a 32-hole drift round and a 9-hole slab round had been drilled and blasted in the drift at the north end of the stope.
At approximately 7:45 p.m., James Skalsky, shift boss, accompanied by Adelbert Adkins, night foreman, witness, entered the stope on Skalsky's usual rounds.
When Adkins entered the stope, he noticed the back and the walls had been wet down and the miners were barring down in the stope. Adkins reported that he did not observe any unusual ground conditions in the stope, and ground conditions were not discussed between the miners and supervisors.
Skalsky, the two miners, and Adkins sat down adjacent to 34 ore pass and discussed the work schedule for that shift, which consisted of slushing out the drift and slab rounds that had been blasted by the previous shift and also the drilling of another drift round and slab round. Skalsky then made out some sample tags for the miners. After the sample tags were made out, the four men got up and started walking toward the south end of the stope.
Adkins was in the lead, followed by Skalsky, Kinney, and then Schamber. Skalsky and Adkins were going to leave the stope, and Kinney and Schamber were going to get the slushier ready to slush out the previously blasted drift and slab rounds. They proceeded about 20 feet, when Adkins said he heard simultaneously a yell and a rock snap and crack. He threw himself against the west wall and landed on his side, from where he saw a large rock fall on Skalsky , Kinney , and Schamber.
The rock which fell on the victims broke into a number of pieces upon impact, but it was estimated to have been originally approximately 24 feet long, 6 feet wide, and from 1½ to 4 feet thick.
The two miners and shift boss on the opposite shift stated that during the previous shift the rock which fell showed no signs of cracks. However, they also stated that there was some unstable ground to the northwest of the area involved in the accident.
Since the known unstable ground was still in place at the time of the investigation, what bearing it had on the accident could not be determined. Skalsky and one of the miners were notified of this loose material before the shift started.
During the investigation, a 2-inch-wide crack was observed along the hanging wall where the ground fall occurred, and loose ground was also observed on the hanging wall to the south of where the fall occurred.
Cause of Accident
The direct cause of the accident could not be determined. A contributing factor may have been that due to the size of the rock which fell, presently employed methods of detecting loose material were not adequate.
||Historical Summary of Mine Disasters in the United States - Volume III