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Characteristics and reclamation of “acid sulfate” mine spoils Coal

At termination, each pot was placed into a wooden rack and leached with 500 mL of deionized water. Passage of 500 mL of water was equivalent to 1.5 pore volumes and corresponded to a single 5-cm rainfall/infiltration event. The pots drained freely for 24 h or until leaching stopped. The total leachate was collected, weighed, and a 100-mL aliquot was filtered using a 0.45 μm membrane filter.

Surface mining in the Appalachian region of the United States is known to generate acidity through the oxidation of pyritic minerals in the overburden when exposed to water and oxygen. The extremely acidic conditions combined with poor plant nutrition status, and elevated concentrations of hydrolyzable metals and trace elements make it difficult to revegetate and reclaim these areas. Runoff from overburden, known as acid mine drainage, poses a threat to both ground and surface water quality. Research has shown that the application of organic matter, particularly biosolids, on acidic mine spoil aids in revegetation efforts by acting as a source of alkalinity and providing essential nutrients, such as nitrogen and phosphorus.

The current study was initiated in 2007 to investigate the influence of spoil type on soil development and tree growth over time. Data from the first two years after plot construction supported brown sandstone as the most favorable spoil type for tree growth, with gray sandstone and mixed spoils being unfavorable . This paper reports on the 10-year results from this experiment. Salt extractable Al concentrations were reduced by this Miscanthus biochar.

Brinks, J.S.; Lhotka, J.M.; Barton, C.D.; Warner, R.C.; Agouridis, C.T. Effects of fertilization and irrigation on American sycamore and black locust planted on a reclaimed surface mine in Appalachia. Ninot, J.M.; Herrero, P. Effects of reclamation measures on plant colonization on lignite waste in the eastern Pyrenees, Spain. And J.M.; software, C.B.; validation, C.B. And K.S.; formal analysis, K.S. And C.B.; resources, C.B.; data curation, C.B. And K.S.; writing—original draft preparation, K.S.; writing—review and editing, K.S., C.B., C.A.

The first recommendation, dealing with spoil selection, is especially important, because different spoil types can place sites on different soil development trajectories. SMCRA permits the use of a “soil substitute” if native soils are too shallow or slopes are too steep to allow for retention of native soils prior to mining—a common occurrence in Appalachia. However, this soil substitute was traditionally just mine-run spoil—a mix of the various overburden types disturbed during the mining process.

Impact of alternate landuses on Nitrogen mineralization in dry tropical forest. Ecological studies of revegetated coal mines of Indian dry tropical environment. Zipper, C.E.; Burger, J.A.; Mcgrath, J.M.; Rodrigue, J.A.; Holtzman, G.I. Forest restoration potentials of coal-mined lands in the eastern United States. Craw, D.; Rufaut, C.G.; Hammit, S.; Clearwater, S.G.; Smith, C.M. Geological controls on natural ecosystem recovery on mine waste in southern New Zealand.

Additionally, NAG has been demonstrated to be elevated in ecosystems with increased fungal biomass (Miller et al., 1998). The low activity rates of NAG in this study, coupled with a lack of response to any of the treatments, is more than likely indicative of low fungal populations in the spoil utilized in this study as determined by PFLA results (Fig. 2). The literature has reported mixed soil enzyme activity on exposure to biochars with results ranging from highly variable (Bailey et al., 2011) to having a significant positive impact (Lu et al., 2015; Jian et al., 2016). Likewise, NAG activity in the mine spoil soils were on average approximately 50% less than reported in the same study by Hou et al. . Even 10 years after plot construction, spoil type significantly influenced soil chemical and physical characteristics.

Lime was more effective at increasing mine spoils pH and EC than the Miscanthus biochar, even at the highest biochar application rate (5% w/w; Table 4). Only biochar applied at 5% however, was able to significantly raise the pH compared to the other treatments (0, 1 and 2.5% biochar). Overall, application of 0.8% (w/w) lime was sufficient to adjust the spoil to a pH range acceptable for Blue Wildrye growth . Thirty seeds of Blue Wildrye were spread across the spoil surface and were hand raked into the surface to a depth of 5 to 10-mm.

To better assess site differences not reflected by soil texture and chemistry, soil surface temperature was logged for 19 days using HOBO® temperature probes (Onset® Computer Corporation, Bourne, MA, USA) installed on one plot per treatment. Due to logger malfunctions, no data were collected for Brown, and only one logger michael jackson doll per treatment collected usable data for the other spoil types. In addition, canopy cover was estimated using a method adapted from Barton and Karathanasis . Briefly, in August 2018, a 1.4-million-pixel aerial photo was captured using the standard 12-megapixel high-resolution digital camera mounted on a Phantom 4 drone .

For enzymes analysis, a total of 5 g of field moist spoil was collected from each pot and stored at 5°C, samples were stored for less than 24 hours prior to enzyme analysis. Spoil slurries were prepared by using 1 g of spoil, mixing it with 25 mL of modified universal buffer and homogenized by vortexing. Spoil suspensions were then transferred into a 2 mL deep 96 well plate, along with methylumbelliferyl-labeled substrates, covered and incubated at 35°C for 90 minutes. After the incubation, plates were centrifuged for 3 min at 2,900 × g, and 250 μL of supernatant was transferred to a black micro titer plate.