1.12. As explained in Ref. [3], the term ‘near surface disposal’ generally refers to disposal at or within a few tens of metres from the surface of the ground. The term ‘geological disposal’ generally refers to disposal in deep, stable geological formations, usually several hundred metres or more below the surface. Disposal facilities for mining waste cover a spectrum of designs, from above ground mounds of waste to geological disposal of tailings slimes (a dispersion of fine tailings in water), which are sometimes used as backfill in old mines. The type of disposal required depends on the characteristics of the waste and the potential risk that the waste may pose to the environment [3]. The suitability of waste for disposal in a particular disposal facility is required to be demonstrated by the safety case and supporting safety assessment for the facility [2]. A dedicated monitoring and surveillance programme is part of this demonstration.