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Mechanized approaches to the rehabilitation of degraded rangeland have been extremely popular since the early 1930s but their effectiveness depends on climatic and environmental conditions (e.g. soil texture, pre‐treatment plant cover). We evaluated the effects of pitting, a popular rehabilitation technique based on the creation of elongated soil depressions (pits), on ecosystem structure from 14 trials conducted at 10 sites across an extensive area (~100,000 km2) of rangelands in eastern Australia. Averaged across all sites and rehabilitation times, pitting had a significant positive effect on the cover of perennial forbs and annuals, and suppressed bare ground compared with untreated sites. However, these treatment effects varied with different site conditions such as soil texture, and pre‐treatment rainfall and plant cover among individual sites. Pre‐treatment plant cover, and rainfall in the 3 months prior to measurements increased the effects of pitting on litter cover, and time since treatment increased the relative effect of pitting on annual plant cover. Negative effect of pitting on the cover of bare soil declined with increasing rainfall. Soil moisture was generally greater beneath pits than either control soils or soils between the pits (inter‐pits). Despite some positive effects on annual plant and litter cover, pitting effects were generally short lived, suggesting that a single pitting treatment may fail to achieve long‐term rehabilitation. Given that these field trials were conducted half a century ago under conditions of higher average rainfall, the prognosis for the success of pitting under current conditions of lower rainfall and higher temperature is generally poor. [ABSTRACT FROM AUTHOR]

Summary: Landscape rehabilitation following mining is required to be resilient to disturbance impacts such as fire, drought and disease. As mining companies undergo the process of rehabilitation certification and mine closure, there are notable knowledge gaps on the ecological risks associated with mature rehabilitated landscapes, based largely on the assumption that rehabilitation is analogous to reference communities. However, the response to fire disturbance across a range of landscapes remains largely untested and in particular there is limited understanding of recovery traits of plant species that occur naturally or are commonly seeded into rehabilitation. In August 2018, a controlled fire was applied to 37 hectares of 12‐year‐old coal‐mine rehabilitation in central Queensland, Australia. We used a combination of (i) ground plot surveys and (ii) drone imagery to compare the vegetation response of burnt woody species to unburnt controls prior to, and for, two years following the fire. The survival of the most dominant shrub species found on the rehabilitation site was significantly impacted by the fire. Old Man Saltbush (Atriplex nummularia Lindl. subsp. nummularia) recorded significant post‐fire mortality, with ground surveys recording an average reduction of 89% of stems per hectare across the burnt site, while unburnt controls remained unchanged. The plot data analysis was supported with high spatial and temporal resolution drone imagery, classified using a Random Forest machine‐learning approach. Change analysis of these maps showed a significant decline of 82% in Old Man Saltbush plant density and 92% reduction in foliage cover following the fire. In addition, the mean canopy area of individual Old Man Saltbush shrubs reduced significantly from a pre‐fire mean of 11.3 to 4.8 m2 two years following the fire. A spatial proximity analysis showed that those individuals that survived the fire were located significantly closer to unburnt areas and bare spoil, indicating that discontinuous ground fuel loads can greatly improve the survivability of individuals. This study provides new evidence on the contested fire sensitivity of Old Man Salt bush and demonstrates the risk that future climate‐driven extreme events may have on the resilience of novel ecosystems. [ABSTRACT FROM AUTHOR]

• Rehabilitation demonstrated recovery trajectories towards or beyond pre-fire levels within 2 years. • Open woodland and grassland became more dissimilar in the 2-years following the fire. • Vegetation communities varied significantly from their pre-fire condition. • Land managers can use controlled fire to manipulate ecological outcomes for post-mine rehabilitation communities. • Future studies should examine the resilience of mine site rehabilitation following disturbance events across a range of locations, seasons and climatic conditions. The application of controlled fire on post-mine rehabilitation is currently underutilised as an ecological tool throughout fire prone landscapes such as eastern Australia. Despite widely accepted benefits of fuel management and ecological outcomes, mined land managers are generally reluctant to incorporate fire regimes on rehabilitated lands. We applied an experimental fire to 117 ha of 19- to 21-year-old coal mine rehabilitation in sub-tropical, semi-arid Central Queensland, Australia, and assessed the vegetation changes in five successive assessments for the two years following the burn. Vegetation metrics all showed trajectories towards pre-fire levels, or recovered to surpass pre-fire levels. Within two years of the burn, native species richness was significantly higher than pre-fire levels for both grassland and open woodland areas and vegetation cover had returned to pre-fire levels. Woody plant density (<2 m) increased from an average of 425–3,255 stems ha−1 in open woodland areas reaching values higher than those recorded at unburnt historical transects (n = 145); while stems greater than 2 m in height declined from 585 to 220 ha−1 due to the death of mature Acacia spp. The vegetative response following two wet seasons demonstrates short-term recovery following a range of fire impacts and demonstrates the potential to enhance the quality of the rehabilitation and increase the possibility of early relinquishment by reducing ecological, financial and reputational risks. [ABSTRACT FROM AUTHOR]

Mining has been a long-standing key player in economic development, employment, infrastructure, and supply of essential raw materials for society. It has served as a viable route to economic transformation in resource-rich countries like Australia, Canada, the United States, and parts of Africa. In this review, the impact of mining has been conceptualized into economic, environmental, and social impacts. While it is clear that mining has transformed many economies, it has also impacted negatively on the environment and, to some extent, society. Some of the negative impacts of mining are loss of vegetation cover, mass destruction of water bodies, loss of biodiversity, land-use changes and food insecurity, increased social vices and conflicts, high cost of living, and air pollution. However, reclamation has been a viable way of reducing the negative impacts of abandoned mine lands and ensure productive and efficient utilization of mine wastelands. Compaction, low or high pH, low water holding capacity, gullies, bulk density, deficiency of micro, and macronutrients are the major factors limiting the productivity of mine wastelands. A combination of physical, chemical, and biological restoration practices is ideal for restoring the mine soil productivity. While the physical method deals with earth-battering, thus putting the land back to shape, the chemical and biological methods include various amendments such as biochar, compost, synthetic fertilizers, synthetic chelates, shrubs, and grasses, and nanoparticles. A combination of these three restoration methods restores soil fertility, stimulates microbial growth, and facilitates early ecological succession. However, before embarking on reclamation, the particular post-mined land use should be clearly stated, such as conservations, forestry, agriculture, construction, intensive recreation, non-intensive recreation, and lake or pool through land suitability and selection analyses. This review has guiding significance and recommendations for mining and post-mined rehabilitation., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The trend towards reuse of effluent for land application of domesticand industrial wastewater is driven by the need to maximize limited water resources and benefit from the plant nutrients available in theeffluent. Of significant impact upon the value of the wastewater forreuse is its chemical properties as well as biochemical oxygen demand and suspended solids. While the sewage treatment plant is expected to treat all wastewater received to a minimum environmental standard,no efforts are given to reducing the chemical load derived from usesof chemicals in the domestic household. That the regulation of industry and commerce far exceeds those of the combined effects of thousands of household is remiss of environmental regulators. This paper examines the results of research into the more common sources of chemical additives to the wastewater stream. Twenty five potable water supplies are examined for their salt load, 20 liquid and 40 powder laundrydetergents and five dishwashing products were used to simulate discharges to the sewer, measured for their phosphorus, salt and sodium concentrations. The results of the research indicate that choices in the products available for general use within the house can be made only where product labeling and consumer education is improved. Technical improvements in wastewater treatment are not the answer. The improvement in effluent quality will have significant beneficial effects upon land application areas and expand the range of reuse options available for commercial operations. [ABSTRACT FROM AUTHOR]

The need to conserve, reuse and recycle water is becoming increasingly important for both environmental and economic reasons. The Virginia Pipeline is Australia's largest water recycling project. More than half the output from (the capital of South Australia) Adelaide's largest wastewater treatment plant is further treated to achieve a product water quality fit for irrigation of vegetable crops with minimal public health restrictions. The project partners have a vision to achieve total reuse. To achieve this vision, recycled water will need to be stored during cool weather periods when the demand for water is low. Temporary storage of this water in poor quality aquifers is the subject of a major research project. [ABSTRACT FROM AUTHOR]