Facility Information
The Rosebud Power Plant is an electric generating facility designed to burn low-British thermal unit (Btu) waste coal from nearby mining operations. The facility uses a circulating fluidized bed (CFB) boiler and has an active CCR landfill and an inactive CCR landfill. The inactive landfill stopped receiving ash and reclamation began in October of 2005 with the addition of topsoil to the site. The inactive ash pit was seeded in the summer of 2006, and reclamation was deemed complete in December of 2006. The active CCR landfill receives whatever ash that cannot be sold for beneficial uses, such as encapsulated reuse in wallboard, concrete, roofing materials, and bricks. Both landfills, as discussed below, contain ash that has been combined with water to form a solid substance similar to concrete.
The CCR ash at the Rosebud Power Plant is deposited while it is dry using a belly dump trailer pulled by a water tank truck. The ash is a pozzolanic material that contains both anhydrous calcium sulfate (CaSO4) and unreacted calcium oxide (CaO), also known as quicklime or unslaked lime. Both compounds have a strong chemical affinity to absorb water, forming a mixture of hydrated calcium sulfate (CaSO4–2 H2O, also known as gypsum) and hydrated lime (Ca(OH)2, also known as slaked lime). The purpose of adding water to the dry ash is to control fugitive dust and to form a solid mortar/concrete-like compound from the ash. Due to the nature of material and how it is stored, the CCR landfill at the Rosebud Power Plant minimizes the potential for CCR releases to the environment.