Drilling operations being conducted by Northern Dynasty Mines north of Lake Iliamna include sinking holes within the Upper Talarik Creek Watershed east of the boundaries of the company's proposed open pit mine, raising concerns that Northern Dynasty might be altering its stated intention to stay out of the creek.
But a company official insisted Thursday the drilling going on away from the pit area itself has nothing to do with assessing future deposit sites, and everything to do with studying groundwater in anticipation of mine and tailings disposal design.
Scott Brennan, campaign director for Alaskans for Responsible Mining, an Anchorage-based environmental group closely monitoring NDM's progress toward a working mine at Pebble, said the drilling could be part of ongoing hydrological studies of groundwater flow, but that it also might be related to mineral deposits discovered in the east zone, which borders and may underlie portions of the Upper Talarik Watershed.
Brennan acknowledged being "a bit of a cynic," but NDM drill maps show activity in the Upper Talarik Watershed, leading him to question the company's commitment to its promise to avoid the sensitive fish habitat.
Ella Ede, NDM's environmental project manager, told the Clarion earlier this month that the company had "made a commitment to stay out" of Upper Talarik Creek.
The current boundary of the anticipated mine pit measures between a mile and 1.5 miles in diameter. It had been smaller, but discoveries on its eastern edge last year led the company to expand the site to its current dimensions. A much larger zone generally to the south of the pit will be used for depositing tailings.
On site at Pebble on Thursday, Ede described the two types of drilling operations currently underway and what they mean to the overall project.
Analysis of the mine's metal potential (including its gold, copper and molybdenum) requires sampling sections of rock removed from drill holes, each of which may take two to three weeks to drill, Ede said. Such core sampling has been and is underway in the mine area itself, including in the eastern area of the pit boundary, Ede said.
Other holes are being sunk beyond the pit boundary in all directions, in some cases miles beyond, that involve no core sampling. They are being used to confirm the region's hydrogeology — that is, how groundwater moves.
"Groundwater drilling is different," Ede said. "It's important because we have to understand how water flows. When we start developing the mine project and start doing our digging, we will encounter water at some point. We must have plans to handle that water in a way that has the least amount of impact on the environment."
Some of the hydro-wells are within the Upper Talarik Watershed, even close to the creek, according to drill maps. But no rock sampling is going on there, she said, and those sites are not being used to look for more deposits or plan for mine expansion.
In some cases, holes are drilled because they are required by the state, said Bob Loeffler, director of the Alaska Division of Mining, Land and Water. While NDM is interested in discovering valuable metals, the state is looking for the presence of things like arsenic, heavy metals and acid-generating compounds — things that would be of concern if released into the groundwater.
The state also wants to know about acid-buffering compounds — chemical that would serve to reduce acidity, like carbonates, he said.
Core samples provide such data.
"They grind up the rock and look at it for metals they care about, and we look for things we care about," Loeffler said.
Also important to the design of the mine, Loeffler said, is the nature of the rock at its periphery. Solid granite would allow for steeper pit walls, while crumbly material might necessitate sloping walls.
Loeffler also pointed out that as far as core sampling goes, there have been core holes drilled all over the caldera, not just around the proposed mine pit. Predecessors of NDM dug some.
"I don't know if historically there have been some in the Upper Talarik or not," he said. "I presume they have been dug all over. It is a mineralized area. Some holes were drilled to locate valuable metals, some just to help understand the geology. That doesn't bother me, as the government, because core sampling has reasonably limited impact on the environment."
He also noted that should drilling of any kind lead Northern Dynasty to suspect the presence of recoverable metals of value elsewhere in their claim holdings, there was nothing to prevent the company from pursuing permits for anther pit.
What impact NDM's proposed mine is likely to have is under assessment now as part of a feasibility study due out around the end of the year. But the company holds claims to only a part of the huge caldera that covers a significant portion of the Bristol Bay Watershed. A company called Liberty Star has claims on roughly three times the territory controlled by NDM, and other mining companies have smaller claims in the area.
While none of these other companies has progressed as far toward an actual mine than NDM, state officials are watching all the mining survey activity closely, Loeffler said, adding that Alaska has a competent permitting group and a good track record when it comes to mining operations.
"My job is to prevent those serious disasters and I intend to be successful," he said.
