Exploration work at Greens Creek Mine has yielded results that could extend the mine’s life, it announced this week in a press release.
Greens Creek wrapped up its 2017 exploration work and reported finding more minerals than it mined last year, making Greens Creek officials optimistic the mine can stay open past its 10-year timeline.
“The exploration results that we released are extremely encouraging as we continue to find more material adjacent to and within our existing ore bodies,” said Mike Satre, spokesman for Hecla Greens Creek Mining Co.
The 839,589 tons of rock processed at Greens Creek last year contained 10.8 million ounces of silver, 78,245 ounces of gold, 60,858 tons of zinc and 22,870 tons of lead — a lot to take out of the ground. But the material Greens Creek mined was offset by new finds next to and between areas already mined. In other words, Greens Creek actually came out of 2017 with more silver, gold, zinc and lead left to mine than they went into the year with.
“We were actually able to replace silver, gold and lead reserves across the board,” Satre said.
How much more? Silver, gold, zinc, and lead reserves increased by 2, 8, 7 and 4 percent, respectively.
Greens Creek spends millions of dollars a year on mineral exploration. They have to prove there’re minerals in the ground before they can apply for permits to extend the mine’s “life,” or the duration they expect the ore body to continue yielding a profit.
They do this is by drilling holes in the rock and assessing mineral samples, sometimes between areas already mined and sometimes in new areas. Those amples are used to prove — to varying degrees — what minerals exist in the ore body and in what abundance.
Greens Creek’s ore body is “incredibly complicated,” Satre said, so it’s hard to know how long the mine’s life may have been extended by the 2017 exploratory work. But the mine has had success with exploration in the past. After low metal prices ground production to a halt in 1993, accelerated exploratory drilling helped the mine reopen in 1996. Since reopening, newly discovered reserves have helped the mine extend its life several times.
• Contact reporter Kevin Gullufsen at 523-2228 and kevin.gullufsen@juneauempire.com. Follow him on Twitter at @KevinGullufsen.
