The first mines in the area shipped all of their raw ore to smelters across the border in the U.S. for processing. As the ore qualities diminished and shipping expenses rose, the mining companies built smelters in the area to process the ores. The Consolidated Mining and Smelting Company Limited in Trail, the Granby Mining and Smelting Company in Grand Forks, and the Dominion Copper Company at Boundary Falls were built to process local ore. Gradually the ore bodies ran out and the smelters in Grand Forks, Boundary Falls and Greenwood closed. Cominco in Trail remained, as it had diversified it supply of ore by purchasing the St. Eugene Mine in Moyie and the Sullivan Mine in Kimberley. These smelters became the largest customers of the local hydropower. Cominco eventually bought out West Kootenay Power & Light to secure its constant need for electricity.