THE Government has initiated a probe to determine the historical mining methods employed at old mines, spurred by the recent collapse of shafts being exploited by artisanal and illegal miners, Mines and Mining Development Minister Zhemu Soda said.
In an interview on Wednesday, Minister Soda said understanding the techniques employed historically would provide insights into potential vulnerabilities and stability concerns.
Most of the mines are believed to have been operated by Germany companies.
Indications are that the illegal and artisanal miners are jeopardising the stability of old underground mines by extracting gold from support pillars, resulting in structural failures.
Fifteen gold miners were recently trapped underground at Redwing Mines for four days after the shaft they were working in collapsed. While authorities initially suspected an earth tremor as the cause, independent and official assessments suggest that the miners might have been extracting gold ore from the supporting pillars, potentially contributing to its collapse.
“We have also discovered that some miners are being allocated land with old workings underneath. So, they drill to gain access to the old workings…extract the pillars that are supporting the ground. We have similar incidences in other mines that have been previously mined by Germany companies,” Minister Soda revealed.
“Apart from Redwing Mine, we are also carrying out an exercise at other old mines especially those which have been previously operated by German companies.”
Pillar extraction is a mining technique where support pillars left behind during initial ore extraction are later removed to access additional ore. While this can be a profitable practice, it can compromise the stability of the mine, increasing the risk of collapses.
The possibility of pillar extraction as a contributing factor in the Redwing Mine collapse has sparked widespread concern and calls for a thorough investigation. Some questions have been raised about mining practices at the site, potential safety violations, and the role of Metallon Gold Zimbabwe in ensuring worker safety.
Minister Soda, said he directed the provincial mining team to ascertain the actual mining methods being employed and come up with recommendations. “I am yet to get that report but obviously we will come up with measures informed by the report,” he stated.
The primary reason for leaving support pillars is to maintain the stability of the mine. The pillars help to distribute the weight of the ground above, preventing cave-ins and collapses. This is especially important in areas where the ground is weak.
According to mining experts, the decision of whether or not to extract a support pillar is a complex one that must be made on a case-by-case basis. There are many factors to consider, including the safety of the miners, the stability of the mine, and the economic viability of extraction. They say support pillars can be very dangerous.
If not done properly, it can lead to cave-ins, collapses, and other accidents. In some countries, there are strict regulations in place governing the extraction of support pillars.
In October last year, at least nine people died while 22 others were rescued until the Government called off the search to retrieve the trapped miners at Baya Horse mine in Chegutu. The Government declared the accident a national disaster.
Dozens of miners drowned in 2019 as floods swamped Kadoma’s Silver Moon and Cricket mines.