We studied the effects of soil handling operations during bauxite mining and restoration on the numbers and depth distribution of seed stored in the surface soil of the jarrah forest. Germinable seed stores were determined in four sites of undisturbed forest, these same sites after clearing and burning of forest residues, in the soil immediately following the construction of topsoil stockpiles, in the respread topsoil and then after deep ripping of the respread topsoil. Average density of germinable seed at four sites prior to disturbance was 352 m−2. After clearing and burning, the seed store had decreased to a mean 74% of the original forest soil seed store density. When the top‐soil was stockpiled prior to respreading, the seed content was further reduced to 31% in freshly constructed stockpiles and had declined to 13% after 10 months in the stockpiles. After ripping of the respread topsoil the seed content was 16% of the original forest seed store density. In one site where the topsoil was directly stripped and respread with no period of stockpiling but with a period of fallow, the seed store was 32% after respreading and then increased to 53% of the original forest store after ripping. This increase may have been caused by an underestimate of the reserves due to insufficient heating of the samples to break dormancy in fire‐requiring species. In the forest topsoils seed was concentrated in the upper few centimeters of the soil profile, whereas after the mining and restoration operations seed was evenly distributed throughout the returned soil profile to a depth of 20 cm. Small‐seeded annual species, which were common in the forest seed store, were more sensitive to the soil handing operations and declined to very low numbers, whereas hard‐seeded plant species such as Acacia spp. were less affected by the soil handling operations. Implications for bauxite mine revegetation operations include the recommendation that direct return of topsoil should be carried out wherever possible with a minimum delay between clearing, stripping, respreading, and ripping.

The restoration of the high botanical diversity of the premining jarrah (Eucalyptus marginata) forest is a major priority of rehabilitation following bauxite mining in southwestern Australia. This study investigated the effects of different ripping, seeding, and scarifying dates on the establishment of plants from propagules stored in the topsoil and from applied seed on areas being rehabilitated after mining. Seed stored in the topsoil, rather than applied seed, was the major contributor to plant diversity. Ripping late (April) or scarifying in June significantly reduced the number of species and numbers of individual plants that established from propagules in the topsoil. Species originating from broadcast seed were most numerous when the seed was broadcast in April or after scarifying in June. Scarifying before seeding, particularly in June, increased the establishment of species from the broadcast seed. To make best use of the applied seed, without jeopardizing the establishment of species from the topsoil, pits should be ripped and sown by April. We list a number of strategies that can help maximize plant numbers and botanical diversity on rehabilitated bauxite mines, which may also be of more general application for restoring the original native vegetation on disturbed sites.

Deep ripping, using a conventional chisel-tine to a nominal depth of 1.4 m, was introduced to Alcoa's operations on the Darling Plateau in 1969 following windthrow of a number of trees. Although research into mine floor compaction showed that this ripping depth was sufficient to remove the mining compaction, tillage studies showed that plastic failure around the point of a conventional tine ripping to this depth was actually adding to deep compaction rather than removing it. To improve tillage at depth, winglike structures were attached to the shank of a conventional chisel-tine directly behind the point. These wings lift and till the soil across a broad front. Wingspans between 0.75 and 1.8 m were tested, and a final design of 1.8-m wingspan adopted for ripping during the 1980s and 1990s. Availability of suitable steels in the late 1990s allowed the winged tines to be fabricated from scratch, enabling the fitting of wear plates to almost completely eliminate shank wear and breakage problems, though these additions have resulted in some loss of tillage efficiency. Modification of the bulldozer ripping box is highly desirable for ripper design to be improved further, particularly to overcome lateral sliding when contour ripping is undertaken on steep slopes. An alternative is to divide the ripping process in two: a pre-rip up and down the slope followed by shallow ripping on contour. A two-step ripping process is now being used at Alcoa's Western Australian bauxite mines.