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specialized blasting consulting

specialized blasting consulting
client
Fermilab and University of Minnesota
location
Minnesota

big bangs on behalf of particle physics

Remote Ash River, Minnesota, was chosen as the site for a massive underground detector that will enable researchers to study neutrinos. Neutrinos are subatomic particles produced primarily by nuclear reactions in the sun and other stars. Traveling at close to the speed of light, about a trillion neutrinos pass through our bodies every second.

The Fermi National Accelerator Laboratory will fire a beam of neutrinos at a small detector on its Illinois campus and study the evidence of changes that occur in the particles during their 500-mile, three-millisecond journey to the large detector in Ash River. Researchers hope to learn more about the three varieties of neutrinos, which in turn should provide clues about why the universe has more matter than antimatter—a circumstance that allows stars, planets, and people to exist.

Deep rock at the northern Minnesota site will help shield the detector from solar radiation, but it also complicated construction. To accommodate the 15,000-ton detector, crews had to blast through an area of rock 350 feet long, 50 feet deep, and 82 feet across at its widest point. Barr was hired to provide specialized blast consulting and rock-mechanics modeling. 

Blasting was complicated by the rock’s brittleness and its tendency to break along its natural layers rather than along planned grade lines. Closely controlled drilling techniques, sequenced blast timing, and a complex system of rock bolts and tension anchors that secured certain areas while others were being blasted enabled excavation of 56,000 cubic yards of schist and granite to tolerances of just a few inches. We also developed techniques for blasting rock without compromising the integrity of new concrete structures at the site.

Site construction was finished in 2011 and the detector is now in service.

Photo: Dan Traska, Einarson Air