In the UK, what we commonly know and term as Grit Salt is in actual fact Rock Salt.
There are three main Rock Salt mines in the UK supplying most of the country.
Rock Salt works by lowering the freezing point of the path or road surface on which it is placed, preventing ice from forming and also melting existing snow and ice on the surface.
It should be ideally spread on the road or path when the surface is damp, this helps the salt stick to the surface, the layer is more effective when ground down by pedestrians or vehicular traffic. When ground down by traffic, the salt turns into a brine or salty water, spreading over the surface and melting the ice.
Applying and spreading the Rock Salt in snow can require up to four times more than spreading to counteract a light frost.
Ideally, Salt should be put down when sub-zero temperatures have been forecast.
The price of Rock Salt steadily rises as we go deeper into the Winter months. During the severe winter of 2010, the price had risen almost three or four times more in November / December than the price paid in September, the price is obviously also subject to weather conditions and stock availability.