Mexico uses cinders for snow and ice traction and there may be some interest in knowing where the material comes from, what it is and how we use it.
Where it Comes From
Mexico obtains its cinders from the Thomas Hill Power Plant. That plant uses a cyclone type boiler and the material we call cinders is more properly called boiler slag. It is the molten bottom ash and is a different material than the fly ash that is very fine and is collected from the exhaust flue of the plant. Both are composed of the inorganic (non-burnable) minerals present in the coal.
Thomas Hill has been burning low sulfur coal since 1994 and the boiler slag is primarily silicon. This is the same chemical composition of most sand. It is very angular and hard which is why it works well for traction.
The mixture that Mexico uses on its roads is 1 part salt, 3 part cinders, and 2 parts limestone screenings. The expected weather conditions and temperature of the road surface are used to determine what tools are used for snow removal.
A brine mixture is used to pre-wet bridge decks and road problem areas to help keep snow from sticking or ice forming. Traction material is applied as slick spots develop. Snow is plowed to remove as much as possible prior to the application of salt and traction material so that the amount of salt and cinders on the roadway is minimized. It doesn’t take as much salt to melt an inch of compacted snow as it does to melt 3 inches. Environmentally, the less grit material and salt that can be used to maintain clear roads the better.
As storm water regulated community, we need to operate in as environmentally friendly a way as possible. Street sweeping of the grit is a part of that stewardship, keeping the grit out of the storm water.