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These stories were provided by five of CIM's Industry Partners and originally appeared in the December 2023 - January 2024 issue of CIM Magazine (view it in flip format here).
Pioneering mining method through innovation
Hecla’s Underhand Closed Bench mining method harnesses the power of controlled seismic activity at its Lucky Friday mine.
If you visit the Ford Museum in Dearborn, Michigan, you will see that Hecla’s 1903 100-horsepower hoist was powered by the longest transmission line in the world. This is just one example of Hecla’s long history of innovation.
For more than 130 years, Hecla has fostered a company culture that values continuous learning, remains open to new ideas and is willing to adapt to change. Hecla has discovered that the best ideas are often years in the making, and success and failure are an important part of the learning process.
For example, construction of the Silver Shaft at its Lucky Friday mine in Idaho allowed for several innovations: paste backfill, rubber-tired equipment and a new mining method called the Lucky Friday Underhand Longwall (LFUL).
After using the LFUL method for 35 years, issues with Lucky Friday’s seismic activity made it apparent that it was time to find a new mining method, and Hecla took a huge leap.
“We were reaching for the Holy Grail of mining: a method for productively cutting preconditioned rock while removing the miner from the face,” said Hecla president and CEO Phil Baker. “To meet this challenge, we developed a mechanical mining machine, the Remote Vein Miner (RVM), that could rapidly cut preconditioned rock.”
Baker equated investing in the RVM with exploration. Most exploration work is not successful, but it is still a necessary part of reaching a successful outcome. The RVM was no different. At times, Hecla thought the RVM might not work, but the company could learn from the experience. This approach led Hecla from the RVM to a solution that was even better—the Underhand Closed Bench (UCB) mining method.
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Chris Neville, Hecla’s current vice-president and general manager, Lucky Friday, was at the forefront of recognizing the challenge of seismicity. Growing up in Mullan, Idaho, Neville recalled sitting in his high school classroom and feeling the vibration of rockbursts from the mine. Windows would rattle, then the sounds of sirens would fill the town as the volunteer ambulance crew raced to the mine.
Neville shared this perspective to demonstrate how far Hecla has come, thanks to the UCB method. Building upon years of research, testing and analysis, Neville and his team crafted a creative yet simple solution. Instead of merely managing the effects of seismic shifts, Hecla now harnesses the power of controlled seismic activity.
UCB consists of drilling a series of blasthole rings 24-feet deep in the longhole stope floor, then initiating an explosion that uses 25,000 pounds of explosive to blast 10,000 tons of rock at once. The explosion triggers rapid yet controlled seismic activity. With UCB, more than 90 per cent of total seismic energy around the stope is released over the course of 12 hours. This method releases 100 times more fragmented ore than the traditional cut and fill method.
Neville explained that by blasting a longer, deeper area when personnel are out of the mine, miners can more safely, quickly and efficiently move the ore. With traditional methods, it could take up to 10 weeks for the energy to be released. Through UCB, Hecla achieved stability within one work shift.
This method revolutionized Hecla’s approach to operating in seismically poor areas. The mine has gone from miner control, to engineer and management control, by shifting towards task-based mining, where management decides how mining is done.
The results speak for themselves. Lucky Friday has been using the UCB mining method since 2020, during which time it realized the best safety record in its history, and increased production by 150 per cent.
“Innovation comes from not being afraid to try and fail. We’re motivated by Every Day, Every Shift, Home Safe, and that’s led us to solutions that reduce risk and raise confidence. UCB was built on the shoulders of our predecessors that put the hours, days, weeks, months and years into studying the problem, and I’m proud to be a part of the team that developed a mining method that is making a difference,” said Neville.
Hecla has discovered that innovation builds upon itself. It is an ongoing process that did not begin with the UCB method, and it will not end there either.
