LAKE LINDEN – Some of the equipment and techniques used in the geophysical investigations of the Department of Environmental Quality’s ongoing project on abandoned mining wastes in the Torch Lake area was displayed at a Tuesday open house.

The ground is measured using an electromagnetic induction profiler, and also ground-penetrating radar.

Sometimes, the shape of the waveform can indicate the type of container, such as a drum, said Jeff Pincumbe, a geologist with the DEQ.

“If it’s just a dump of everything, it’s going to look like that,” he said. “You can’t tell what it is.”

Areas being looked at include the area near PCI in Hubbell with copper; the Tamarack Sands, where sinkholes have been spotted; and a site near an asbestos abatement.

Monitoring near PCI didn’t reveal much: a fence post, and some concrete with metal caps. Some PCBs were found near the edge of Torch Lake.

“We knew that was there,” Pincumbe said. “That’s why we wanted to expand the area.”

On foot, getting readings takes about an hour per acre, using 5-foot grid patterns, Pincumbe said. The devices are set up to deliver a reading every second.

Sites were found during earlier visits. While doing soil boring last year, the DEQ found drum-shaped sinkholes. Historical data also plays a part.

“People come up to us and say, “Hey, that area is where we used to dump our refrigerators,” or something like that,” Pincumbe said.

When lab analysis comes back, interpretation begins immediately, Clark said. For the first portion, a report documenting the findings is available at the Lake Linden Public Library. The DEQ also hopes to put the report of on a website within the next month.

For some areas, they will come back in the fall and use a geoprobe for soil and groundwater samples to determine any problems. From there, they will decide whether to dispose of it safely or just make sure it stays covered.