A successful pilot program means the Town of Gravenhurst has completely switched to using a treated salt product for winter road management instead of traditional rock salt.
Before the 2019/20 winter season, the town used standard rock salt, according to a Nov. 21 report from Andrew Stacey, Director of Infrastructure Services, which he says was the industry norm at the time and inexpensive.
However, he explained one of the cons is the amount of chloride it leaves behind, which Stacey wrote could have a negative effect on watersheds.
“Largely through the lens of operational improvements including an awareness of chloride impacts, the public works division piloted a treated salt program commencing in the second half of the 2019/2020 winter season,” he continued. “Treated salt products are typically made from rock salt, which are then coated with additives such as magnesium chloride, beet juice, or an acetate deicer to improve their performance.”
He said the benefits include the product being more likely to stick to the round and not bounce, melting ice quicker, and being effective at a lower temperature than rock salt.
Stacey wrote that between the last winter season only traditional rock salt was used in 2018/19 winter season to when the switch to treated salt was made in 2021/22, 181.56 fewer tonnes of salt was used, or 23 percent.
“Traditionally, with the use of rock salt, it would be common for an operator to revisit the salt route three times during a single winter event to achieve the desired results being observed currently,” explained Stacey. “With the treated salt, the number of required passes for a given winter event has been reduced (depending on the type of winter event) to one to one and a half times per winter event.”
According to Stacey, Gravenhurst maintains around 231 km of road in the winter, however, only 39 km are salted to limit how much is used.