Pioneer Aggregates Plant, Washington

 CalPortland operates this aggregate mine and processing site on Puget Sound, south of Tacoma, to harvest Steilacoom Gravel, a layer of rock material deposited along the coast by glacial action. This is one of the largest sand and gravel operations in the United States, and is a major source for building material in Washington State. Seven miles of conveyors move material around the site and out to a barge loading dock, from where most of the material is shipped to customers. This facility opened in 1997, after Lone Star depleted an even bigger quarry two miles up the coast at Steilacoom, a site the company worked for around a hundred years, heavily transforming the local topography.