Pay limit - Grade below which the mining of ore is considered to become unpayable. There has been much discussion about mining below the pay limit for technical reasons, as a result of taxation, or to conserve natural resources.

All-in sustaining costs is an extension of the existing “cash
cost” metrics and incorporates costs related to sustaining
production.

All-in costs include all additional costs that reflect the
varying costs of producing gold over the lifecycle of a
mine.