Salt, sand, and brine is applied to roadways in order to provide traction and break down snow and ice on the surface. Brine can also be used as an anti-icing agent that is applied 24 hours before a forecasted freezing rain event as outlined in the Minimum Maintenance Standard of Ontario.
The CNB sand dome, capable of storing up to 12,000 tonnes of winter material, is located at the Public Works Yard on Franklin Street. The dome is filled each summer and a separate pile of 8,000 tonnes of sand is stockpiled and kept on hand outdoors on a concrete pad. This stockpile is typically used as an emergency supply and to replenish in the event the indoor pile has been exhausted.
Throughout the winter months, salt is imported into the sand dome on an as needed basis. There is roughly 1,000 tonnes to 1,500 tonnes of salt on hand at any given time.
Outside the sand dome, there are two 20,000-litre tanks storing brine solution. Brine is a 23 per cent sodium chloride solution used for anti-icing/de-icing and pre-wetting sand and salt to allow the material to work more effectively as it limits scatter during application.
Salt material is stored at Franklin Street. The dome provides overhead coverage to protect the salt and sand material from adverse weather conditions.
The City of North Bay is mandated to complete a Salt Management Plan to comply with the Environmental Management of Road Salts. The purpose of the plan is to introduce and use new and effective practices which would reduce the use of road salt while minimizing the environmental impact without affecting the level of public road and pedestrian safety. During the winter of 2018-2019 the roads department disbursed a total of 2,695.12 tonnes of straight salt on 182.61 lane kilometres of roadway.
Winter sand is applied to provide grit and traction on snow and ice, and is typically used in weather conditions where the temperature is colder than -12C. Sand is being used on low volume roads and on gravel roads where salt is not an option. Winter sand contains a measure of salt to prevent freezing of the material and allows the sand to flow more smoothly out of the spreader units when applied to the roadways.
The provincial standard for the application of winter sand is 570 kilogram per 2 lane kilometres. This standard is used by the City. In 2018-2019, 16,736.14 tonnes of sand mix was used on 811 lane km of roadways.
Over the years, road maintenance authorities have experimented with a number of innovations to improve winter maintenance. These innovations have included early application of materials, the use of alternative de-icing chemicals and pre-wetting of salt with various liquids.
Anti-icing is the proactive way of applying chemical freezing-point depressant on a highway pavement prior to the start of freezing precipitation to prevent a strong bond between frozen precipitation or frost, and pavement surfaces.
This process prevents the development of a bond between the snow or ice and the pavement surface. Less chemical is required, snow and ice removal is easier resulting in safer and more reliable road travel.