Legacy silver miner embraces latest underground mining tech Metal Tech News – February 17, 2021
Established in 1891, Hecla Mining Company has survived two global pandemics, two World Wars, the Great Depression, and numerous crests and troughs of a cyclical metals market that has sunk many of the silver miner's contemporaries over the past 130 years. One of the reasons for this long-lived success is a readiness to adapt to change and the vision to adopt new technologies that maximize safety, improve efficiency, and reduce the environmental footprint of its operations in the United States, Canada, and Mexico.
"The one thing that is certain is change, so we have to continue to get better each and every day, in every aspect of what we do," said Hecla Mining Vice President of External Affairs Luke Russell. "We don't rely on 'well that is the way we did it yesterday,' there may be a better way."
This mindset of utilizing the latest technologies to continually improve operations is on full display at Hecla's Greens Creek Silver Mine in Southeast Alaska.
Thanks in large part to the implementation of 21st century technologies, such as high-speed wireless and semi-autonomous mining equipment, Greens Creek produced 10.5 million ounces of silver in 2020, which is roughly 77% of the 13.5 million oz recovered from all of Hecla's operations last year.
"This definitely is not your grandfather's mine," Hecla Greens Creek Mine penned on the innovations page of its website.
Connection is key
The centerpiece of the cutting-edge mining technologies being implemented at Greens Creek is a high-speed wireless data transfer system that includes miles of communication cables and wireless hotspots that connect the working areas of the underground mine.
Hecla said this connectivity provides real-time data on where every person and piece of equipment is located, even in the labyrinth of underground passages extending more than a mile below the earth's surface.
Originally installed as a safety measure to enable radio frequency identification (RFID) technology to help track workers and equipment, the high-speed wireless data transfer offered by this underground wireless network enables a broad range of technologies.
This means that you are more likely to see an underground worker at Greens Creek pull out a tablet with real-time data than reams of paper to take notes that will need to be transferred to the company's computer system when they get back to the surface.
"The geologists can go into that work area and rather than having 20 maps with him, he has a tablet and he looks up the face map, the mine plans for that area, from that tablet," said Bob Haecker, mill manager at Greens Creek.
The wireless underground network at Greens Creek also allows for the operation of fully remote and semi-autonomous mining equipment from the surface.
The first of such equipment, put to work at Greens Creek in 2017, was a remotely operated semi-autonomous long-haul dump loader operating during shift changes at Greens Creek.
An operator sitting behind a bank of computer monitors on the surface runs the LHD on the first pass, teaching the machine where to load and dump, and then the loader repeats the process.
Operating through two shift changes a day, each taking about two hours, this avant-garde piece of equipment provides the mine with about four extra hours of ore hauling every day at the underground operation.
Hecla says another advantage of the autonomous LHD, which has proximity detectors that prevent it from running into other objects, is its ability to operate quicker without running into walls than a similar loader with a human being jostled around in the driver's seat.
With the success of this semi-autonomous loader, Hecla says it is adopting automated, jumbo stope drilling and shaft operations between shifts. The company is also expanding its usage of tele-remote and battery-powered loaders and trucks at its operations.
The company says these emissions free and unmanned equipment "reduces ventilation requirements, improves worker safety, and lowers emissions."
On-demand fresh air
Closed quarters and with no breeze, maintaining fresh air for workers is an important and expensive part of any underground mine.
At Greens Creek, Hecla is using the wireless underground connectivity for on-demand ventilation, an optimization-via-automation approach that targets the vital process of supplying fresh air to underground miners in their scattered workplaces while exhausting the used air that has acquired excess heat, noxious gases, and dust.
By mounting variable-frequency drives to the underground fans that circulate fresh air through the underground workings at Greens Creek, the ventilation system is able to adjust the amount of fresh air delivered in response to the people and equipment in an area.
The company says just one of these drives lowers the annual power bill at Greens Creek by about $23,000. So, the mine could save around $1.26 million per year when all 55 of the fans are equipped with these drives.
During the testing phase, Hecla installed the money-saving variable drives on 14 of the fans.
"We're already saving money today, and can roll out this technology throughout Greens Creek and our other mines to potentially save even more in the future," Hecla penned on the innovations page of its website.
Remote vein miner
As a forward looking company, Hecla has its eyes on the future of underground mining. This includes being the first company to order Atlas Copco's remote vein miner, a state-of-the-art mining machine that incorporates the multiple steps of underground mining into a continuous operation.
With a cutterhead that digs into the face being mined, the remote miner does away with the drilling and blasting traditionally used to break up ore.
This innovative mining machine is being put to use at Lucky Friday, an Idaho silver mine just four miles from where Hecla got its start in 1891.
Since its start in 1942, Lucky Friday has produced more than 155 million oz of silver, along with healthy quantities of lead and zinc. Hecla first bought into Lucky Friday Silver-Lead Mines Company, operator of the underground mine, in 1958. Six years later the two companies merged, bringing Lucky Friday into the Hecla portfolio.
Hecla is taking Lucky Friday to new depths with the No. 4 shaft, which will develop mineralization 10,000 feet below the surface and add more than 20 years of silver-rich ore to the operation.
The remote vein miner is expected to become increasingly important as Hecla follows the rich silver ore deeper into the Lucky Creek Mine.
"We see mechanical rock cutting as an important step forward to significantly increase productivity and safety as we mine at greater depths at the Lucky Friday, and are proud to be working with Atlas Copco, a leader in the field, to develop the remote vein miner," said Hecla Mining President and CEO Phillips Baker, Jr.
It is this work at the cutting edge of underground mining technology that is expected to keep the 130-year-old Hecla going strong through the 21st century and beyond.