(d) the stocks are built up in the authorised area where they will not be disturbed or subjected to excessive erosion; If stored for more than 30 days, inventory must comply with the requirements of § 816.22 or § 817.22 of this chapter. (b) The minimum depth of soil and soil materials to be removed and stored for the reconstruction of prime agricultural land must be sufficient to meet the requirements of paragraph 823.14(b). 1. Topsoil shall be removed separately or other suitable soil material shall be removed if such other soil material creates final soil with a higher production capacity than existed before dismantling. If this material is not used immediately, it must be stored in separate stocks from the hive and all other excavated material; and (2) separately remove soil horizon B or C or other suitable soil material to provide the suitable soil thickness required by paragraph 823.14(b), unless authorized by the regulatory authority if soil horizons B or C would not otherwise be removed and soil capacity can be maintained. If each horizon or other material is not used immediately, each horizon or other material must be stored separately from overburden and all other excavated material. If combinations of these soil materials obtained by mixing have been shown to be equal to or more favourable to plant growth than horizon B, separate handling is not necessary. (c) land abstraction and storage operations on first-category agricultural land shall be carried out in order to: -.