Effects of Biochar and Marble mud on Mine Waste Properties to Reclaim Tailing Ponds

Abstract

The effects of biochar addition in improving soil physical properties are not clearly understood in mining tailings. The objective of this study was to determine the effects of three different types of biochars, in addition to marble mud (MM) and their mixtures, on the structural stability and water retention of mine wastes in Cartagena, Spain. Biochars were produced at 500°C from pig manure (PM), cotton (Gossipium hirsutum L.) crop residues (CR) and municipal solid waste (MSW). Biochars were added to the mine waste (MW) along with MM and a control (no amendments added). These mixtures were incubated in cores for 90 days (25°C). PM and CR mixed with MM decreased soil bulk density (from 0 · 98 g cm -3 to 0 · 89 and 0 · 84 g cm À3 , respectively). Amendments had no significant effect on total porosity whereas they increased gas diffusion by 100%, except for MSW. MM improved the plant available water from 0 · 59 to 2 · 56 cm as its combination with biochars, extremely relevant in water scarce climates. The micropores were likely replaced by mesopores when application of PM, CR, MM, and biochars + MM and they improved water retention. Total carbon (TC) and total nitrogen (TN) increased by using biochars and MM and no significant effects were assessed on aggregates. In general, MM mixed with PM and CR derived biochar improved the structural stability and exhibited a strong impact in reclaiming physical quality on mine tailings.

Easily mineralizable carbon in manure‐based biochar added to a soil influences N2O emissions and microbial‐N cycling genes

“…Biochar is a carbon‐rich solid material obtained from thermochemical conversion (pyrolysis) of biomass in an oxygen‐limited environment (Lehmann et al, ). Application of manure‐based biochar to low‐quality soils has been considered as a strategy to: (a) reduce the large volume of manure generated annually, (b) increase carbon sequestration (Coomes & Miltner, ), (c) improve soil fertility (Wang, Xiong, & Kuzyakov, ), and (d) remediate contaminated soil (Mohan, Sarswat, Ok, & Pittman, ; Muñoz et al, ). Recently, concerns have been raised about the greenhouse gas emissions, in particular N 2 O emissions, induced by the application of manure biochar to low‐quality soils.…”

Changes in soil chemical properties as affected by pyrogenic organic matter amendment with different intensity and frequency

“…Pyrogenic organic matter improves soil properties but also the environment (Paz-Ferreiro et al, 2014). The PyOM is used for agricultural soils (Hüppi et al, 2015) affected by salinization (Wu et al, 2014;Drake et al, 2016), under intense agriculture land (De Melo Carvalho et al, 2014;Weyers and Spokas, 2014) but also on shifting agriculture as charcoal (Coomes and Miltner, 2016) and to restore mine soils and quarries (Muñoz et al, 2016).…”

Biological Stabilisation of Tailing Pond Coasts with Use of Mineral and Organic Substances and Water-Absorbing Geocomposites

“…On the other hand, the application of crop willow chips had the most beneficial influence on the compactness as it was reduced by 13.5% in comparison with the object without additives. Improvement of physical quality on mine tailings after the addition of organic amendments was observed by Muñoz et al [29]. The application of geocomposites allowed us to reduce sediment compactness by 5.7%.…”