Case Study: Granite Rock


Courtesy of Willowstick Technologies LLC

The world is changing. Consider the environment: In just a couple of decades, our knowledge of the world around us and how we affect it has caused significant shifts in the way we act. The best example of this lies with our corporate culture, as companies have to consider their impact on the world as well as their overall profitability.

Industries that rely on the earth are in a precarious situation. Companies in the mining industry in particular face closer scrutiny of their practices in harvesting and storing their product. Some of them have been content to stay with old, questionable practices.

Other companies are going above and beyond new regulations and requirements by taking proactive measures to ensure a minimal impact on their environments. The benefits are being felt not only in greener practices, but companies are finding out more than they’ve ever known about what sits below their quarries and affects them on a daily basis.

The Problem

Consider the case of Graniterock, a Watsonville, California-based construction products and services company with constant recognition for the quality of their work and the way they choose to run their business. The company has received awards for their commitment to the community as well as the employee-friendly work place and environmentally friendly practices. Graniterock manages a large quarry located near Monterey Bay, California. Over time as the quarry has expanded and proceeded deeper into the ground, the company has needed to be more aware of the subsurface characteristics, in particular the groundwater flow paths that impact the water going to and from the quarry.

“The site was a quarry with a complex hydrogeology,” noted Jon Erskine, a senior scientist at Graniterock. “We needed to understand where their groundwater flow paths were coming from, where they were going and how much volume of water we might be producing as we lower and expand the quarry.”

Complicating the situation even more was a river located next to the quarry. Erskine worried that any exchange flow paths between the two would be a potential environmental hazard.

Graniterock takes great pride in their environmental record, to the point where the company is one of the few that takes preemptive steps to protect the environment, as opposed to waiting for regulators to force action.

Protecting the quarry from the river and vice versa, plus being able to understand how the geology would change as the quarry expanded was critical. The key was finding where the groundwater paths were.

“We did a simple groundwater model to try and predict how much water was going to come into the quarry. The person that did the model predicted that water would be coming in from everywhere, instead of these discrete, fractured pathways. He estimated a lot of water would come in, which would be expensive to remove and would have an environmental impact on the river.

“This isn’t the case with most quarries, but because ours is so big and next to some sensitive water bodies, we really had to understand (the subsurface characteristics.)”

The Solution

After the initial modeling, Erskine looked for something more concrete. After looking into seismic refraction and a geothermal surveying company that could provide limited data, he called upon Willowstick, makers of AquaTrack(TM), which seemed to be the perfect fit for the quarry project.

AquaTrack works by measuring magnetic fields generated by an AC current, which is applied using strategically placed electrodes that are in direct contact with water flow. After multiple unobtrusive readings taken by a Willowstick surveyor, the data is applied to mathematical algorithms and used to create maps and three-dimensional models of the subsurface groundwater paths. There is no requisite well drilling involved, no large equipment and no extra personnel to manage.

“I first learned about Willowstick by reviewing another project I was overseeing in Las Vegas,” Erskine explained. “They were brought in by an engineering firm, and I remember seeing how the technology was used to map out groundwater pathways. I thought it would be very applicable to what we were wanting to do here, which was map out very complex, discrete water flow pathways.”

Within a short period, Erskine was in conversation with Willowstick, and the two sides agreed to a test drive.

“Our corporate strategy was to do a pilot study before we jumped in with both feet,” said Erskine. “We picked an area we felt we knew a lot about, and ran a test to see if the technology held up.”

Not only did the technology hold up, but Erskine said it revealed a large groundwater pathway in the middle of the area that he had suspected was there but had no prior confirmation. “The technology just nailed it,” he said.

“We eventually did three or four surveys and mapped out the whole quarry,” Erskine said. “We used the technology to figure out where we should put monitoring wells and pumping wells.”

Within a matter of months, Erskine held a complete set of information AquaTrack surveys had pulled. In that data was every piece of significant information he would need about the subsurface water pathways, mapped out in clear and easy-to-understand form.

“It’s been the best tool we’ve had for really identifying groundwater pathways,” Erskine said. “The more I dig through survey results the more little things I find that I didn’t really appreciate before. It’s a very rich data set.”

The Business Benefit

Erskine said he appreciates the confidence he has in the information pulled from the surveys. “We’ve designed our groundwater monitoring and characterization program based on the results of the Willowstick survey.

“Without the Willowstick data, we wouldn’t have been able to build our understanding of how the site works. We would’ve had to go forward kind of willy nilly.”

A key aspect of being confident in the information provided is knowing precisely where to place monitoring tools, which are costly to purchase and install.

“Each monitoring well we put out there is very, very expensive; each one could be up to $100,000,” Erskine noted. “This has helped us optimize where to put these things. If we had just gone in dead reckoning where to put them, we might just be in a different ballgame because we would have been misled by incorrect information.”

Erskine also noted the speed and agility of the surveys, and the responsiveness of the Willowstick team to changing needs.

“I was very happy with the turnaround time, which was very quick. I liked the fact that when the guys (Willowstick engineers) were out in the field they were constantly updating me. We adjusted some surveys on the fly for better results, and they were very attentive. I was very impressed by the way that worked out.”

In the end, what the data means for Erskine and Graniterock is total confidence in what lies beneath the vital quarry, and the ability to act on that data in a way that protects not only their investment, but the environment as well.

“We’re looking for legitimacy with the regulatory agencies; we can go there and show them this data and the independent lines of evidence (such as subsequent tests) that say the same thing.

“The value is high quality data, which to us is really important. Because of that and the good work we do, we have good relationships with those agencies.”

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