How Should Mine Reclamation Design Effectively Respond to Climate Change? A Mini Review Opinion

Climate change is a growing concern with each of the last three decades being successively warmer than preceding decades. Mine wastes are mandatory required to be reclaimed after mine operation due to their high risks of contaminating environment and huge volumes occupying large useable land resources. However, most traditional mine reclamation plans are designed with an assumption of unchanged, consistent conditions of environment, climate and hydrology conditions, which may not work properly under the global climate change. This paper discussed the previously ignored problem that is how mine reclamation design should effectively respond to climate change. Through reviewing the current responding strategy to the climate change during mine reclamation and closure, this mini review was structured, and the opinion is concluded that the more active the designers consider the factors of climate change, the more manageable, predictable and sustainable the reclaimed ecosystem and landscape are. Nature-based solutions can act as the general guidelines when considering climate change with mine reclamation, and the six-step framework aims more specifically on mine reclamation. The two methods can work together to help designers and regulators to effectively respond to climate change when planning mine reclamation and closure.

Technosol made from coal waste as a strategy to plant growth and environmental control

Coal waste disposal areas demand proper rehabilitation activities because several environmental impacts are related to them,such as acid mine drainage,loss of biohabitats,water pollution,and soil degradation.The most common strategy is to cover them with an impermeable layer followed by a new soil layer as soon as possible,while maximizing plant growth and avoiding water and wind erosion.This study examines the possibility of transforming coal waste itself into a substrate for plant growth,namely technosol,assuming its own use for progressive rehabilitation and revegetation of waste deposits.The coal waste is amended with other residues in an integrated waste management approach:rice husk ash,steel slag,and sewage sludge to adjust physical structure,pH,and nutrient availability,respectively.The raw material composition,fertility,metals bioavailability,plant growth,and nutrients in plant tissue are analyzed after successive growth of lopsided oats(Avena strigosa)and maize(Zea mays).The results show that coal waste allows a fertile plant substrate after being amended in accordance to experimental conditions.The soil metal concentration is found to fall within the limits of natural variation for soils in the study area and nutrients in plant tissue are found to be consistent with lopsided oats and maize standards.The proposed waste mixture results in a technosol capable of adequately promoting plant growth,that is,it is a potential resource to accelerate revegetation and natural succession in coal waste disposal areas.

Earthworm rather than biochar and sodium silicate addition increased bacterial diversity in mining areas subjected to chemical fertilization

The addition of biochar,sodium silicate,or earthworm is a feasible practice to repair soils disturbed by mining activities,and the reclamation is largely based on the alteration of the diversity and structure of soil bacteria.The objectives of this study were to assess the relative importance of these supplements on soil bacterial community diversity and structure in reclaimed mine areas.A field experiment with soybean was carried out in mining areas to assess the efficiency of nitrogen,phospho-rus and potassium(NPK)fertilizers plus those supplements on soil bacterial community structure and diversity by the 16S rRNA sequencing method.Soil chemical properties were analyzed to their effects on the bacterial community structure.The results showed that the application of nitrogen,phosphorus and potassium(NPK)fertilizers significantly increased bacterial diversity,and a further increase was observed in NPK plus biochar,sodium silicate or earthworm addition.Furthermore,a higher number of genera were found in the NPK plus biochar and NPK plus earthworm treatments than that in the control,NPK and NPK plus sodium silicate treatments.The bacterial community was significantly associated with nutrients,such as carbon(C)and nitrogen(N).Moreover,soil organic carbon(SOC)and pH were the most dominant factors in shaping the soil bacterial community structure and diversity.Our data indicate that the addition of earthworms to soil rather than biochar and sodium silicate was the best strategy to mitigate the detrimental effects of mining activities on soil bacterial diversity.