La. R.S. 31:33

Operations conducted on land other than that burdened by a mineral servitude and constituting part of a conventional or compulsory unit that includes only a part of the land burdened by the servitude will, if otherwise sufficient to interrupt prescription according to Articles 29 through 32, interrupt prescription only as to that portion of the tract burdened by the servitude included in the unit provided such operations are for the discovery and production of minerals from the unitized sand or sands.