The three Hy-Tech Drilling workers that were trapped underground at Newmont’s Red Chris gold-copper mine in British Columbia, Canada, have been safely brought to surface following fall of ground incidents last week.
All three individuals are safe, and in good health and spirits, the mining company said on Friday, adding that they had consistent access to food, water and ventilation while they remained in place in a refuge chamber underground over the last two days.
Newmont said it conducted a “carefully planned and meticulously executed rescue plan” to locate and rescue Kevin Coumbs, Darien Maduke and Jesse Chubaty.
“We are deeply grateful for the support from our industry partners, and proud of the culture of teamwork demonstrated from our team members at both our Red Chris and Brucejack operations in British Columbia as well as across our wider global business,” it said. “Kevin, Darien and Jesse demonstrated the utmost dedication to our safety procedures, adhering to protocols for more than 60 hours underground.”
While the mining company now intends to conduct a comprehensive investigation into the incident, it shared some extra details that underscores the precise nature of the rescue plan.
On the morning of July 22, two fall of ground incidents occurred in the access way to the underground work area of what Newmont says is “a non-producing project” at Red Chris. At the time of the initial incident, the three business partner employees were working more than 500 m beyond the affected zone and were asked to relocate to a designated refuge station before a subsequent fall of ground blocked the access way.
A Newmont spokesperson confirmed to IM that the refuge chamber the personnel used was a MineARC Systems MineSAFE Standard Design Refuge Chamber, designed to provide personnel with optimum safety features, functionality and performance, all while complying with internationally recognised refuge chamber guidelines. With a capacity for 16 people, these chambers have several vital life-support systems to create a safe, ongoing environment for occupants, MineARC says. Systems include primary and secondary air (oxygen) supplies, air conditioning systems, positive pressure systems, electrical systems, gas detection and a chemical scrubbing system.
Following the first fall of ground event, contact was established with the individuals and confirmation was received that they had safely relocated to one of these refuge bays. The second fall of ground event subsequently restricted communication to them.
In coordination with industry partners, Newmont deployed specialised drones to assess the geotechnical conditions underground. These drones, Flyability Elios 3 drones, rely on computer vision and LiDAR mapping to perform systematic inspections. The drone’s LiDAR payload, as standard, offers SLAM-based mapping.
The visual inspections aided by these drones confirmed there was debris blocking access to the underground area. This was estimated to be approximately 20-30-m long and 7-8-m high.
In the meantime, teams worked on restoring the leaky feeder communication system in that area of the mine to re-establish communication with the workers.
To remove the debris and restore access beyond the incident site, Newmont drafted in a Cat® R1700 LHD – operated via line of sight remote control – from its Brucejack site, some 140 km away. At 8:30 pm local time on July 24, this LHD successfully cleared the fallen debris from the access tunnel.
With the area stabilised, the Emergency Response Team advanced across the impacted zone using a Sandvik Toro® LH621i fitted with an engineered Falling Object Protective System (FOPS). Sandvik states that this LHD has a certified ROPS and FOPS cabin, laminated safety glass windows, emergency escape windows and an illuminated entrance.
Upon reaching the refuge chamber, the team found the three personnel in stable condition. Together with the Emergency Response Team, they returned to surface using the same protected equipment.
Newmont concluded: “This outcome is the result of tireless collaboration, technical expertise and above all, safety and care. We extend our heartfelt gratitude to the rescue teams and all those involved, and to Kevin, Darien and Jesse as they recover from this experience.”