Sept Iles is a port having an important iron ore export function, while Hamilton port is an iron ore importer and a steel exporter. Industries in this domain are generally linked to port sites, as two important commodities for making steel, iron ore and coal, are ponderous materials. In 1996, the ports of the St. Lawrence Seaway handled 4.5 million tons of coal. Most of it are used by steel mills and thermal plants directly adjacent to port sites or having their own port infrastructures. For coal, economies of scale are very important as coal is ponderous and not expensive per unit of weight.
Ports generally undertake two main functions for handling coal.
The first involve loading the coal directly to an ocean-going ship. Depending where you are on the St. Lawrence, the size of the ship is limited. This commodity has basically two major purposes, which are road de-icing and chemical applications. Since the Seaway is closed during winter months, when de-icing salt is mostly used, large stock piles must be accumulated during fall at several port sites such as Montreal and Quebec. In fact, almost every port site along the St. Lawrence acts as a stock pile.