A dam is a barrier for the containment or accumulation of liquid substances, or a mixture of liquids and solids, forming a reservoir. The concept encompasses the entire dam system: reservoir, main dam, internal dikes (if any), and saddle dikes. Its primary purpose can be to store water, sediments, mining tailings, or generate energy. Dams that store tailings, sediment or water in a mining environment can also be generically referred to as "mining dams".
 

What is a Dike? 

A dike is an accessory structure used to assist in the formation of a dam reservoir. A dam can have none, one, or more dikes. Some dams have saddle dikes, which are built on topographic saddles, with the aim of assisting in reservoir formation. There can also be internal dikes, which are structures built within the reservoir, with the aim of increasing dam storage capacity. At Vale, dikes are generally referred to as “structures” or “geotechnical structures”, and are always assigned identification

What is a Tailings Storage Facility? 

A tailings storage facility (TSF) is a drained dam and/or stacked stcture storing tailings. For dams, it encompasses the entire system (i.e., the main dam, and saddle dikes and internal dikes, if any). TSF identification names match those of the related dam or drained stack.