Digging into Geotechnical Engineering: Specialty expertise supports safer, more efficient mining operations.

• Author: Simonelli, Isaac Stone

Climate change is putting additional pressure on the already complex, yet vital, role geotechnical engineers play in the Last Frontier's mining industry. It is an issue the engineering community is working to address according to HDL Geotechnical Services Manager Doug P. Simon.

"We are often designing projects that we hope will last for decades, and climate predictions are estimates at best with no one knowing for certain what the climate will look like in ten years, let alone decades from now," says Simon. "Geotechnical engineers need to stay informed about the latest information on the climate predictions and how to incorporate the uncertainties into designs."

Geotechnical Reports

Projects with proper funding and organization usually bring on a geotechnical engineer as one of the first planning steps, explains Cody Kreitel, a geotechnical engineer for PDC Engineers. The goal of the suite of geotechnical services offered by engineering firms is to characterize the subsurface conditions at a project site so that developers are aware of any challenges involved with creating the stability necessary for a structure, road, airfield, dam. or even to keep a mine from failing,

Alaska's diverse geology creates a variety of challenges for such engineers, who must rule out various solutions depending on the soil matrix of a site, which can include deep organics that have no load bearing capacity, permafrost, and the liquefaction potential of saturated sands.

"Liquefaction is when, due to cyclic-loading, a saturated loose soil will build up excess pore pressure in between the soil grains and, during the shaking [from an earthquake), the soil behaves like a fluid," Kreitel says. "We saw the effects of that during the earthquake last year."

Kreitel says that despite the necessity of having a geotechnical report for a project, developers sometimes get "sticker shock" from the price of the services, particularly for projects being developed in remote locations since transporting the tools and sending a team to such sites to collect samples is an expensive endeavor.

Once a geotechnical engineer has collected samples and conducted laboratory tests on them, he or she will put together a report for the client, Kreitel explains.

"A geotechnical report presents all of the data I've collected and then recommendations to the designers for the design and construction of whatever project they're working on," Kreitel says. "Sometimes it's a pretty lengthy geotechnical report that lays out what they need to know about the subsurface so they can proceed with their design."

One industry that doesn't tend to balk at joining forces with geotechnical engineers is the mining industry, which...