Adequacy of rehabilitation monitoring practices in the Western Australian mining industry

Summary Currently in Western Australia (WA) there are no mandated standards for assessing rehabilitation success for the mining industry. We argue a case for focusing on the creation of near‐natural, self‐sustaining, functional ecosystems as the primary objective for rehabilitation programs and where this is not achievable, mines should plan to be ‘environmentally neutral’ by undertaking some improvements to degraded landscapes. We suggest that flora and fauna monitoring are appropriate tools for managers and regulators to obtain information on the extent to which a rehabilitated area has achieved a near natural, self‐sustaining, functional ecosystem similar to that in the adjacent undisturbed area. This monitoring can also be used for completion criteria and closure plans. We report results from a short questionnaire sent to mine site environmental managers to assess the extent of flora and fauna monitoring in rehabilitation areas. Survey results highlighted the need for a more systematic and consistent approach to the monitoring of flora and fauna in rehabilitated mining areas in WA. Of 36 respondents, 23 mines monitored flora, three monitored fauna and two monitored both.     

Planning mine restoration through ecosystem services to enhance community engagement and deliver social benefits

Mining companies are expected to return land to a stable, productive, and self‐sustaining condition by rehabilitating degraded areas to also deliver social benefits, an essential dimension of sustainable land management. This research aimed to develop a framework for mine rehabilitation planning based on an integrated analysis of the social‐ecological system provided by the ecosystem services concept to facilitate community engagement and the delivery of social benefits. An Ecosystem Services Assessment for Rehabilitation framework was tested at two bauxite mines undergoing ecological restoration. The mines are operated by the same company in two countries. Key results showed that the framework can help companies, regulators, and community members alike identify whether biophysical restoration efforts translate into key human benefits. Overall the framework provides a means for enhancing community engagement to explicitly address social benefits that, with a business as usual focus on ecological goals, may not be delivered. The ecosystem services concept provides a practical approach to link ecological and social outcomes of mine restoration.     

Two‐tiered methodology for the assessment and projection of mine vegetation rehabilitation against mine closure restoration goal

Reinstatement of a ‘self‐sustaining native ecosystem’ is an increasingly common revegetation goal for open‐cut mines in Australia. This is usually applied as a regulatory requirement for mine closure, with some mines aiming for a high standard of ‘ecological restoration’. There is a growing appreciation that ecological restoration outcomes of mine rehabilitation are unachievable within the life of a mine and that assessment methodologies are subjective and inadequate to provide the high degree of confidence needed for mine closure. Here we elaborate on the integration of the BioCondition assessment and the Ecosystem Dynamics Simulator (EDS) trajectory methodologies. We also demonstrate an alternative early relinquishment assessment criteria similar to that used for early recruitment of regrowth native vegetation that exhibit structural characteristics of undisturbed native vegetation into remnant status in Queensland. We used ten age cohorts of rehabilitation ranging from three to 22 years at Meandu coal mine, south‐east Queensland. All the sites gained average BioCondition scores ranging from 19 to 44 out of possible score of 65. Growth trajectories indicated decline in species and basal area on all sites in the next three decades as the dense stock of short‐lived acacia species senesce and die. None of the sites are projected to meet self‐sustaining status by 2072, but there is evidence in some of a progression. All the sites except two (K2.3 and SW2) are projected to achieve remnant vegetation status by 2062. Applying the remnant vegetation criteria results in shorter timeframes and robustly evaluates whether sites are progressing towards the self‐sustaining ecosystem mine closure goal.     

Comparison of Post‐mining Rehabilitation with Reference Ecosystems in Monsoonal Eucalypt Woodlands,Northern Australia

Rehabilitation of post‐mining lands frequently aims to create “self‐sustaining” systems. Where native vegetation is the designated post‐mining land use, it is generally assumed that rehabilitation that is similar to local native ecosystems is more likely to be sustainable. I compared landscape functionality, plant community composition, and vegetation structure in (1) reference sites representing pre‐mining native forest; (2) reference sites representing potential landscape analogues for the post‐mining landscape; and (3) a 23‐year chronosequence of post‐mining rehabilitation on the Weipa bauxite plateau, Cape York Peninsula, Australia. The trends across the post‐mining chronosequence indicate that vegetation growth is rapid in the first 5–8 years, and then slows with mean height approaching an asymptote after approximately 15 years. Landscape function indices showed a response that coincided with vegetation growth. Vegetation composition was significantly different from reference native forest. Most importantly, from the perspective of creating self‐sustaining ecosystems, the contribution of local framework species to vegetation in rehabilitation was significantly lower than in reference native forest. I discuss the results in relation to theoretical models of succession and conclude that without management intervention, differences between post‐mining rehabilitation and native forest are likely to be persistent.     

Site vegetation characteristics are more important than landscape context in determining bird assemblages in revegetation

The effectiveness of revegetation in providing habitat for fauna is expected to be determined both by within‐site factors and attributes of the landscape in which a revegetation site occurs. Most studies of fauna in revegetation have been conducted in landscapes that have been extensively cleared, modified or fragmented, and in Australia, predominantly in the southern temperate zone. We investigated how within‐site vegetation attributes and landscape context attributes were related to bird species richness and composition in a chronosequence of post‐mining rehabilitation sites within an otherwise intact landscape in tropical northern Australia. Our working hypothesis was that bird species richness in rehabilitating sites would be positively related to site vegetation structure and landscape context including (1) proximity to woodland and (2) the proportion of woodland within a 500‐m buffer of rehabilitation sites. Within each of 67 sites, we sampled vegetation once and surveyed for birds eight times over 16 months. Landscape context variables were calculated using GIS. There were large differences between bird assemblages of woodland and rehabilitation sites and between age classes of rehabilitation. Bird assemblages were strongly related to site vegetation attributes across all rehabilitation sites. Proximity to woodland was only related to bird assemblages in rehabilitation sites older than 4 years old. We conclude that the relative importance of landscape context and site variables at any point in time will be a function of how closely vegetation within the revegetation site matches the habitat resource requirements of individual species.     

State-and-Transition Successional Model for Bauxite Mining Rehabilitation in the Jarrah Forest of Western Australia

Alcoa World Alumina Australia has been rehabilitating bauxite mines in the jarrah (Eucalyptus marginata) forest of western Australia for more than 35 years. Completion criteria were developed in the 1990s for native species rehabilitation, with various desirable characteristics described as the rehabilitation ages. Successional models can be useful in mining rehabilitation for predicting whether sites are developing along the desired trajectory toward the rehabilitation objective. The current rehabilitation objective is to establish a self‐sustaining jarrah forest ecosystem, planned to enhance or maintain water, timber, recreation, and conservation values. The major objective of this study was to present a state‐and‐transition successional model that assists Alcoa to identify sites that will and will not meet identified completion criteria. Agreed completion criteria and vegetation data collected from native species rehabilitation from 9 months to 15 years old were used to construct a state‐and‐transition model. The model identified the various desired and deviated successional states and factors that cause transitions between these states. Five desirable and nine deviated states were identified and described in detail. Key indicators relating to desired and deviated states include eucalypt density, species richness, legume density, topsoil cover, vegetation structure, ripping depth, and tree health and form. Identified management manipulations to return deviated states to the desired successional trajectory include ripping, reseeding, replanting, weed control, and tree thinning. Some of the identified thresholds between desired and deviated states will require significant management input (e.g., reripping), whereas others require little or no input (e.g., recovery following wildfire). Of the 6,429 ha of native species rehabilitation undertaken between 1991 and 2002, 98% is on or above the desired successional trajectory. More than half of the rehabilitated area is regarded as being above the desired trajectory because of high tree density. Although these sites meet the existing completion criteria, management input may be required in the future, emphasizing the importance of identifying maximum and minimum completion criteria. The state‐and‐transition model of successional development is a practical but rigorous land management tool that has the potential to be applied in a wide variety of ecosystems and wide range of land uses.     

Poor recovery of woody vegetation on sand and gravel mines in the Darwin region of the Northern Territory

Summary Sand sheets near Darwin support a distinct heathland vegetation type which includes the habitat of several threatened species. Sand and gravel are extracted from shallow mines in this region. Woody vegetation recovery in 31 small, shallow former sand or gravel mine sites near Darwin that were up to 27 years old was assessed and compared to paired unmined control sites. Recovery in vegetation structure within each mine was calculated as the percentage of that in the control site. Mined sites recovered about 50% of their stem count and canopy cover, but only about 10% of basal area and mature tree count. Gravel mines showed poorer recovery than sand mines. Time since mining had no significant effect on the extent of recovery, but deeper mines had significantly poorer recovery. Only 35% of woody species in sand controls were present in mine sites, and 41% of gravel control species were present in former mine sites. It is unlikely that recovery will significantly improve in coming decades. Sand mining affects about 40 ha of land per year in this region, but is likely to increase in the future. If Darwin expands to a population of 1 million people, and mine sites are not fully rehabilitated, all of the sand‐sheet vegetation in the region could be removed in the next 100 years. Improved rehabilitation and protection is crucial for the conservation of heathland vegetation in this region.     

An Evaluation of Habitat Rehabilitation on Coastal Dune Forests in Northern KwaZulu-Natal, South Africa

The rehabilitation program conducted by Richards Bay Minerals (RBM) of areas exposed to opencast surface mining of sand dunes north of Richards Bay (28°43'S, 32°12'E) on the coast of northern KwaZulu-Natal Province commenced 16 years before this study and has resulted in the development of a series of known-aged stands of vegetation. By assuming that these spatially separated stands develop along a similar pathway over time, instantaneous sampling should reveal successional or other changes usually associated with aging and should provide an opportunity to evaluate the success of rehabilitation. We compare relative densities of pioneer and secondary species, species richness, and a similarity index of the herbaceous layer, tree, beetle, millipede, bird, and small-mammal communities of rehabilitating areas of known age with those of 30-year-old unmined forests and unmined forests of unknown age adjacent to the rehabilitating area. Species richness for all but the mammalian taxa increased with increasing age of rehabilitating stands. For all taxa but the mammals and herbaceous layer, the unmined stands harbored more species than the mined rehabilitating stands. The relative densities of pioneer species of all the taxa decreased with an increase in the age of rehabilitating stands, whereas those of the secondary species increased with an increase in habitat age. Similarity between unmined stands and rehabilitating stands of different ages increased with increasing regeneration age of rehabilitating stands, suggesting that rehabilitating communities, in terms of species composition and relative densities, are developing towards the status of unmined communities. Rehabilitation based on RBM's management program of limited interference is occurring and may result in the reestablishment of a coastal dune forest ecosystem. But rehabilitation resulting from succession depends on the availability of species sources from which colonization can take place. In the Richards Bay mining operation the present mining path is laid out so that such refuges are present.     

Decommissioning Western Australia's First Bauxite Mine: Co-evolving vegetation restoration techniques and targets

Summary   The closure and decommissioning of Alcoa's first mine in Western Australia at Jarrahdale was a landmark for the company. This article describes the strategies and research contributing to successful mine rehabilitation in the Jarrah forest. Lessons learnt at Jarrahdale are being applied to other Western Australian mines. Over 30 years of research have resulted in a strong working knowledge of ecosystem function in this environment. The direct linkage of research to operational practices provides two-way benefits for practitioners and researchers. The Jarrahdale mine is the first mine in Western Australia to have received a certificate of completion from the state government.     

Coastal Dune Forest Development and the Regeneration of Millipede Communities

The rehabilitation of disturbed ecosystems through ecological succession should lead to the recovery of indigenous biological assemblages typical of a region. However, rehabilitation may give rise to unusual successional pathways and lead to atypical assemblages. We compared millipede assemblages along a chronosequence of habitats developing in response to a post‐mining coastal dune forest rehabilitation program with those developing spontaneously in the same area. Our comparison suggests that active rehabilitation mimics and even surpasses spontaneous successional development. On both chronosequences, the total number of species, as well as the mean density, diversity, and species richness increased, and dominance decreased, with habitat regeneration age. Moreover, the similarity of millipede assemblages on the two chronosequences to those on three sets of reference sites (mature forests) increased with regeneration age, but this recovery of community composition occurred faster on the rehabilitating chronosequence than on the spontaneously regenerating chronosequence. This suggests that successional processes are leading to a recovery of the predisturbed state, but factors like protection from further disturbances, which occur on the spontaneously regenerating chronosequence, is probably important to ensure success. The distance between a regenerating site and a colonization source area apparently affects the direction of community recovery—assemblages on the rehabilitating chronosequence converged faster onto assemblages on closer reference sites than onto those on reference sites farther away.     

Salamander diversity of reforested abandoned surface coal mines in the Appalachian Region,U.S.A.

Surface coal mining is a pervasive form of land use and leading cause of deforestation in the Appalachian Region of the United States. Contemporary reclamation practices tend to produce strongly altered landscapes that inhibit forest succession, so there is a need for the development of alternative methods. Surface coal mines that preceded modern reclamation laws, known as abandoned mine lands, have become reforested in many locations and may serve as a model for improving the restoration of forests in postmining landscapes. I compared salamander diversity between 5 forests growing atop abandoned surface coal mines to 5 similar aged reference forests in southeastern Ohio using time constrained transect searches in autumn 2012 and spring 2013. The survey revealed 1,480 salamander individuals, representing 11 different species from 3 different families. The vast majority of salamanders (93%) were from the family Plethodontidae. Salamander species richness was significantly higher in reference forests than in mined forests, but this difference was contingent on the presence of stream‐dependent species in the reference forests. Salamander relative abundance was not significantly different between reference and mined forests. This survey demonstrates that reforested abandoned surface coal mines can provide suitable habitat for many forest‐dependent, terrestrial salamander species, but impaired water quality of headwater streams may limit the colonization of these forests by stream‐dependent species.     

Avoidance of parasitoid attack is associated with the spatial use within a leaf by a lepidopteran leafminer

In prey‐predator systems, top‐down effects can be a powerful determinant for spatial distributions of prey through their search for enemy‐free space. Leafminers live and eat within leaves, making feeding tracks called mines, and mine conspicuousness exposes them to a high risk of parasitism. Those lepidopteran leafminers that use lower leaf surfaces as mining sites show wide evolutionary radiation. We hypothesized that leafminers making mines on the lower surface are less often detected by parasitoids and thus have a selective advantage in avoiding parasitism compared to those on the upper surface. To investigate the adaptiveness of lower‐surface mining, we examined the relationship between parasitism and within‐leaf mine distribution for 3 years using a field population of the leafminer Phyllocnistis spec. (Lepidoptera: Gracillariidae, Phyllocnistinae), which prefers the lower surface of leaves of the Japanese privet, Ligustrum japonicum Thunb. (Oleaceae). Parasitoid attack was more frequent in the upper‐surface mines than in the lower‐surface mines and on leaves with upper‐surface mines than on leaves with only lower‐surface mines. When both surfaces were mined, leafminers on the lower surface could avoid parasitism. Upper‐surface mines were attacked by more parasitoid species as compared to lower‐surface mines. Although the results demonstrated that mining on the lower surface was advantageous in avoiding parasitism, the vulnerability of lower‐surface mines to parasitism varied depending on their abundance. When many lower‐surface mines were present, lower‐surface mines suffered a higher parasitism rate than upper‐surface mines, probably because parasitoids formed search images for and concentrated on lower‐surface mines. This study suggests that the preferential use of the lower leaf surface by leafminers is in part attributed to interactions with parasitoids.     

The influence of hydrogeological disturbance and mining on coal seam microbial communities

The microbial communities present in two underground coal mines in the Bowen Basin, Queensland, Australia, were investigated to deduce the effect of pumping and mining on subsurface methanogens and methanotrophs. The micro‐organisms in pumped water from the actively mined areas, as well as, pre‐ and post‐mining formation waters were analyzed using 16S rRNA gene amplicon sequencing. The methane stable isotope composition of Bowen Basin coal seam indicates that methanogenesis has occurred in the geological past. More recently at the mine site, changing groundwater flow dynamics and the introduction of oxygen in the subsurface has increased microbial biomass and diversity. Consistent with microbial communities found in other coal seam environments, pumped coal mine waters from the subsurface were dominated by bacteria belonging to the genera Pseudomonas and the family Rhodocyclaceae. These environments and bacterial communities supported a methanogen population, including Methanobacteriaceae, Methanococcaceae and Methanosaeta. However, one of the most ubiquitous micro‐organisms in anoxic coal mine waters belonged to the family ‘Candidatus Methanoperedenaceae’. As the Archaeal family ‘Candidatus Methanoperedenaceae’ has not been extensively defined, the one studied species in the family is capable of anaerobic methane oxidation coupled to nitrate reduction. This introduces the possibility that a methane cycle between archaeal methanogenesis and methanotrophy may exist in the anoxic waters of the coal seam after hydrogeological disturbance.     

Rehabilitation of Tropical Lands: A Key to Sustaining Development

Land rehabilitation is proposed as a management strategy to reverse the negative consequences of tropical deforestation and land degradation. We first define the concepts associated with ecosystem modification—conversion, damage, and degradation—and those associated with ecosystem repair—restoration, rehabilitation, and reclamation. We then present a scheme of sustainable land use in the tropics, with illustrations of how rehabilitation and restoration activities fit into the overall scheme of the use of land. Because damaged lands cannot contribute effectively to sustained economic development, land rehabilitation is a necessary step for increasing the chances of attaining sustainability. Approaches for rehabilitating ecosystems are discussed, including the management of stressors and subsidies in relation to their point of interaction in the ecosystem. Finally, we illustrate the concepts of ecosystem rehabilitation of damaged, degraded, and derelict lands with examples of case studies from dry to humid life zones in island and continental situations throughout the tropics. The case studies demonstrate that opportunities for success exist, even with severely degraded lands, but a considerable amount of research remains to be done before we have a full understanding of the complexity of the task facing us.     

Soil moisture dynamics and restoration of self‐sustaining native vegetation ecosystem on an open‐cut coal mine

Post‐mining landscape reconstruction on open‐cut coal mines aims to support restoration of self‐sustaining native vegetation ecosystems that in perpetuity require no extra inputs relative to unmined analogs. Little is known about the soil moisture retention capacity of the limited layer of topsoil replaced (often <30 cm deep), impacts of deep ripping of the profile, and the combined impacts of these on plant available water during the mine restoration process. We examined changes in soil moisture parameters (soil water potential, Ψ, and soil water content, Θ) daily using automated soil sensors installed at 30 and 45–65 cm depths on mine restoration sites aged between 3 and 22 years and on adjacent remnant vegetation sites following heavy rainfall events at Meandu mine, southeast Queensland, Australia. Consistent patterns in soil moisture attributes were observed among rehabilitated sites with generally marked differences from remnant sites. Remnant site soil profiles had generally higher Θ after drying than rehabilitated sites and maintained high Ψ for extended periods after rain events. There was a relatively rapid decline of Ψ on reconstructed soil profiles compared with remnant sites although the times of decline onset varied. This response indicated that vegetation restoration sites released soil moisture more rapidly than remnant sites but the rate of drying decreased with increasing rehabilitation age and increased with increasing tree stem density. The rapid drying of mine rehabilitated sites may threaten the survival of some remnant forest species, limit tree growth, and delay restoration of self‐sustaining native ecosystem.     

Vegetation Succession After Bauxite Mining in Western Australia

Alcoa World Alumina Australia has been rehabilitating bauxite mines in the jarrah forest of Western Australia for more than 35 years. An experiment was established in 1988 using three different seed treatments (legume and small understorey mix, small understorey mix only, and no seed) and two fertilizer treatments (N and P, and P only). The objectives of this study were to (1) document vegetation changes in the first 14 years after bauxite mining; (2) assess whether the vegetation is becoming more similar to the unmined forest; and (3) gain a better understanding of successional processes. Seed treatments significantly affected 13 of the 14 measured vegetation characteristics. Native species richness was higher in seeded than in unseeded sites at 1, 2, and 5 years of age, whereas diversity and evenness were generally higher at all assessment ages. Exotic species density was higher in unseeded than in seeded sites from 5 years onward, whereas richness was higher from 8 years onward. Nitrogen fertilizer significantly increased exotic species richness, density, and cover. Ephemerals dominated plant density in all rehabilitation treatments over time, whereas seeder species dominated cover. In contrast, resprouting species dominated density and cover in the unmined forest. Orchids were the only species that were not present in the first year in rehabilitated sites but increased in abundance over time. Vegetation composition in rehabilitated areas did not become more similar to the unmined forest during the 14 years since seeding, instead strongly reflected the initial species mix. Rehabilitated bauxite mines appear to follow the initial floristic composition model of succession.     

Succession in Bird and Plant Communities over a 24‐Year Chronosequence of Mine Rehabilitation in the Australian Monsoon Tropics

We compared the bird and woody plant communities of 2 to 24‐year‐old rehabilitation areas at Gove bauxite mine (20 km²) in the seasonal tropics of northern Australia, where Alcan has maintained a consistent rehabilitation program since it began operation in 1974. Birds were censused every second month over 2 years in 30 widely separated 0.25‐ha plots, representing five chronosequence stages. These were also compared with six (“off‐mine”) plots adjacent to the mine, which represented the annually burnt open forest typical of the region. Short‐lived Acacias dominated the early chronosequence stages, whereas eucalypts dominated in later stages. Mean avian species richness and abundance increased significantly along the chronosequence, with values for the oldest rehabilitation plots being very similar to those for the off‐mine plots. However, analyses of similarity revealed that the bird communities of the oldest rehabilitation plots were distinct from those of the off‐mine plots, indicating that succession in rehabilitation areas is not following a direct trajectory toward the native open forest surrounding the mine. Several hollow‐nesting bird species were scarce or absent in the rehabilitation areas, probably reflecting the absence of older hollow‐bearing trees. Many differences between the rehabilitation and the off‐mine areas in vegetation structure, woody flora, and avifauna appear to be related to the exclusion of fire from the minesite. We recommend the initiation of experiments designed to assess the effects of fire on the biota but caution against the use of fires for the majority of rehabilitation areas.     

Bauxite Mining Restoration by Alcoa World Alumina Australia in Western Australia: Social,Political, Historical,and Environmental Contexts

Alcoa World Alumina Australia mines bauxite under lease agreements with the Government of Western Australia. The leases lie in the Darling Range to the east of Perth, the capital and major population center. In addition to bauxite and other mineral ores, the Darling Range is a major potable water source and harbors a species-rich forest dominated by Jarrah (Eucalyptus marginata), a significant commercial timber. Conservation and recreation are important land uses in the region. Social and political pressures have led to stringent governmental requirements for restoration. In addition, a summer drought period, a soil deficient in most nutrients, water management challenges, an introduced disease, caused by Phytophthora cinnamomi Rands, and a post-mining ecosystem that must be conducive to the prescribed burning management of the region pose significant challenges to successful restoration. Alcoa presently mines and restores approximately 550 ha per annum. Although the “footprint” at the end of the life of the mining operations represents only about 4% of the total forest estate, Alcoa is committed to restoring the forest values of the region of all lands impacted by mining. The major objective of restoration is to enhance or maintain forest values by restoring habitat and structural characteristics of the native forest environment. Completion criteria for Alcoa’s mine restoration have been developed. The original Alcoa mine at Jarrahdale has been rehabilitated, and in 2005, a 975-ha area received a “certificate of completion” and was returned to the management control of the State of Western Australia.     

Evaluating the sustainability of mine rehabilitation programs in China

Social, economic, and environmental restorations are important concerns in mine rehabilitation programs. Nonetheless, limited attention has been given to the social and economic evaluation of mine rehabilitation programs in developing countries with fast‐growing economies and large populations. To evaluate the social, economic, and environmental sustainability of mine communities before and after mine rehabilitation programs, we placed the study in China, which has experienced large‐scale mine closures resulting from resource depletion. By adopting an integrative model, sustainability cube, we evaluated social, economic, environmental, and overall sustainability (the combination of social, economic, and environmental) of its mine rehabilitation program—the national mine parks (reengineering closed mines as tourist parks, which constitutes the mine rehabilitation program) at the community level before and after the park establishment. Our results indicate that the implementation of national mine parks has improved the overall sustainability of local communities; the sustainability scores of the economic and environmental sectors increased significantly, while the sustainability score for the social sector decreased (mainly due to increased emigration after mine shutdown). We provide suggestions to improve social sector performance in mine rehabilitation programs, aiming to further enhance overall sustainability after mine closure.     

Interaction of multiple disturbances: importance of disturbance interval in the effects of fire on rehabilitating mined areas

Abstract Multiple disturbance regimes are increasingly common as novel anthropogenic disturbances are added to existing natural disturbances. However, it is generally unknown whether simultaneous or sequential effects of different forms of disturbance are predictable from the independent effects of each disturbance. This study examines the short‐term effects of sequential disturbance by mineral sand‐mining followed by fire in a forest community in south‐eastern Australia. Four combinations of disturbance were sampled: unburned mined, burned mined, unburned forest (unmined) and burned forest (unmined, with between‐fire interval matching the disturbance interval between mining and fire of the burned mined treatment). All combinations were sampled approximately 12 months following fire on the burned sites. The impact of fire after mining depended on disturbance interval. Sites burned 0.5–2.4 years since mining had fewer native vascular plant species than unburned mined sites of the same mined age, whereas sites with 10–16 years or 20–26 years between mining and fire had greater native species richness than unburned mined sites of the same age. Burning 20–26 years after mining brought native species richness within the range of burned forest. For both unmined and mined sites native seedling densities increased with burning, and with longer disturbance intervals. Weed species richness and weed seedling densities were greater on mined sites than in forest, and burning mined sites elevated weed seedling densities further, particularly for short intervals. Both disturbance interval and fire intensity are likely to have contributed to these results, as intensity on mined areas increased with interval, and at 20–26 years post‐mining was equivalent to unmined forest. These results suggest that fire could be used to promote rehabilitation of these mined areas after at least 10 years, but should be excluded from earlier stages of post‐mining regeneration. However, other sources of spatial and temporal variability should be considered in addition to interval and intensity, as variation among mined areas was correlated with post‐fire weather conditions and available weed sources. Finally, the combined effects of mining and fire could not be predicted from knowledge of the disturbances operating separately, indicating that effects of multiple disturbance may be synergistic rather than additive.