Reducing salt-use with brine is working for MnDOT

Published: Feb. 6, 2023 at 1:30 PM CST|Updated: Feb. 6, 2023 at 4:29 PM CST
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ROCHESTER, Minn. (KTTC) – The snowplow is the primary tool used by Minnesota Department of Transportation in the winter to keep the roads clear and safe during the winter months. Rock salt is also key tool, but MnDOT is also looking for ways to reduce its use of salt, while balancing the safety needs and travel expectations on Minnesota’s state highways.

Why reduce salt use?

“It’s better for the environment and it reduces our costs. We always balance that with how we maintain safety,” Minnesota Department of Transportation spokesperson Mike Dougherty said.

MnDOT says a 23.7% salt is optimum when creating brine.

In southeast Minnesota, on average MnDOT uses more than 827,000 gallons of brine each year. We also use more than 35,000 tons of rock salt on average each year in our 11-county district.

Brine can be used in many ways to help roads get back to bare pavement.

  • Pre-treating: Drizzling brine on roads and highway ramps in advance puts down a thin, salty barrier to that can reduce compaction – that hard, icy, packed snow that can stick to the pavement and be difficult to remove with plows.
  • Pre-wetting salt: Think about a grain of salt in your hand versus one on your tongue. The moisture can activate the rock salt before it hits the ground. It also softens the salt, which can reduce its bound and improve the precision of where the salt is placed where it’s needed.
  • Cold conditions: Salt loses its effectiveness at 15 degrees. Brine has a lower freeze point, so it can be used below 15 degrees
  • Mixing: Colder temperatures such as single digits or below zero require other products like Beet Heet, which uses the sugars from sugar beets. We can mix brine with it to make this expensive product last longer and better target the strength we need.

Voting closed last Friday in the snowplow contest.

MnDOT will pick the top eight, so there is one new named snowplow in each of MnDOT’s 8 districts, including our District 6 in southeast Minnesota. Look for the class of 2023 coming soon.