Surface Mine Spoil Research Articles

Biodiversity of ectomycorrhizal fungi in surface mine spoil restoration stands in Poland – first time recorded, rare, and red-listed species

Results of mycological research conducted in the years 2001–2013 in the restoration stands growing on reclaimed mine spoils are presented. Four opencast lignite mine spoil heaps in Poland were examined: Pątnów-Jóźwin, Adamów, Mt Kamieńsk, and Turów. The paper focuses on 71 species of ectomycorrhizal fungi: recorded for the first time in the country (16 taxa), currently red-listed (23 taxa), known from few localities only (32 taxa). Notes on their ecology and habitats are provided, as well as their distribution in Europe and in Poland. Restoration tree stands, established as part of the reclamation process of mine spoils, form a unique habitat for many rare and interesting fungal taxa. Among them are pioneer species, species known mainly from Northern Europe or mountainous locations, highly specialized and narrow-niche taxa, and many threatened species. Afforested mine spoils contribute significantly to the fungal biodiversity, both at a local and at a larger scale.

Estimation of carbon sequestration by pine (Pinus sylvestris L.) ecosystems developed on reforested post-mining sites in Poland on differing mine soil substrates

This paper presents an estimation of C-sequestration and relationships between vegetation biomass and reclaimed mine soils in pine (Pinus sylvestris L.) ecosystems in Poland. The study sites were arranged on 8 different geologic/mine soil substrates on waste dumps and surface mine spoils associated with open-cast lignite, sulfur, sand, and hard coal mine spoils. We combined soil and plant biomass data for C and other parameters via a range of site-specific measurements and lab analyses of soil and plant materials for these sites and coupled them with previously derived empirical formulae for biomass estimation. Based on this, we estimated the potential for C-sequestration in post-mining ecosystems and associated internal relationships between soil and plant C-sequestration. Our results indicate significant potentials for development of total ecosystem C stocks (taken as total aboveground biomass+soil+roots) of approximately 50MgCha−1 for even the most oligotrophic habitats in Quaternary sand mine spoils and over 102MgCha−1 for spoil heaps on a sulfur mine in mixed Quaternary sands and Tertiary formation clays, both of which were similar to C stocks in adjacent natural forest pine ecosystems. Litter layer C stocks ranged from 5.9 to 12.7MgCha−1 and total soil C stocks (litter+soil organic carbon (SOC) ranged from 16.8 to 65.0MgCha−1. However, on coal refuse wastes, total soil C stocks were above 2900MgCha−1, which was derived primarily from fossil C. The estimated annual soil C-sequestration rate (in litter+SOC) ranged from 0.7MgCha−1yr−1 to 5.2MgCha−1yr−1 for the 8 sites in this study. Associated C-sequestration rates in organic horizon (litter Oi+Oe) were estimated between ∼0.2 and 0.8MgCha−1yr−1. The estimated range of total annual C-sequestration in post-mine ecosystems (taken as SOC+vegetation biomass across all four mine sites) of this region is 1.6–5.6MgCha−1yr−1.

Alkaline Injection of Concentrated Sodium Hydroxide Solution into an Acidic Surface Mine Spoil Aquifer

A series of NaOH solution injection experiments were performed as trials for in situ remediation of an acid-producing surface-mine spoil. Both 20 and 50% (w/w) concentrated NaOH solutions were employed. While the spoil immediately down-gradient of the injection wells was neutralized, only about 23% of the introduced Na was recovered at the spring discharge in 3 years of post-injection monitoring. This rate of transport was far slower than the estimated advection rates in the aquifer, indicating that substantial retardation of both Na and the associated alkalinity occurred. This retardation is ascribed to: precipitation of alkaline-earth carbonate hydroxide minerals, as well as metal hydroxide precipitates, consuming injected alkalinity; and reduction of hydraulic conductivity in the peralkaline (pH > 13) “plume” region due to plugging by reaction products. It is likely that Na and alkalinity will continue to leak from this plume region for many years, but at too slow a rate to neutralize AMD at current concentrations. Future injection efforts of this type may be feasible but should use lower concentrations and should be focused further down-gradient, in closer proximity to the springs, where ground water velocities are higher.

Settlement of Mine Spoil Fill from Water Infiltration: Case Study in Eastern Kentucky

Mine spoil valley fills are a by-product of mountaintop removal mining in the Appalachian coal mining region of the United States. These fills often result in large expanses of relatively flat land covering thousands of acres, which can be used for commercial or industrial development. However, this material is susceptible to damaging settlement, and highly publicized failures of structures built on mine spoil fills have led to reluctance on the part of investors to develop these areas. A key settlement mechanism in mine spoil is water infiltration. Percolating water slakes the shaly, angular spoil material at interparticle stress points, leading to excessive deformation and settlement. A lumber processing facility in Hazard, Ky., is an example of a structure that sustained serious damage as a result of settlement caused by water infiltration. A forensic site investigation of the facility revealed that excavation of existing surface mine spoil beneath the building footprint removed the low-permeability crust that forms on the top of mature mine spoil fill deposits. The removal of the crust allowed the infiltration of surface water. This, coupled with the unique configuration of the storm water drainage system at the facility and surface water drainage toward the building, led to differential settlement up to 1:120 (vertical:horizontal) and angular distortion up to 1:150 over a period of several months. Foundation underpinning was performed to remedy the situation. For future development on mine spoil sites, recommended mitigating measures include presaturation of the mine spoil, design of drainage systems to adequately convey surface water away from the building, and use of geosynthetic barrier layers to prevent infiltration of surface water into the mine spoil beneath the structure.

English

American chestnut (Castanea dentata (Marsh.) Borkh.) was formerly the most important hardwood species throughout the forests of eastern North America. The introduction of an exotic fungal blight (Cryphonectria parasitica (Murr.) Barr) in the early 20 th century decimated C. dentata populations. Blight- resistant chestnut hybrids may soon be available for widespread distribution through The American Chestnut Foundation's breeding program, although the development of blight-resistant hybrids is only the first step of the restoration process. For successful introduction, more information must be attained about site requirements necessary for successful establishment and growth of American chestnut. Surface mine spoils in the Appalachian coal region and elsewhere may prove suitable for the establishment of founder populations of blight-resistant chestnut hybrids which may then act as reservoirs for chestnut dispersal into surrounding forests. Six research plots composed of three different loose-graded spoil types have been constructed in the Cumberland Plateau of eastern Kentucky to evaluate their effects on tree performance. The three spoil types are: (1) predominately brown weathered sandstone; (2) predominately gray un-weathered sandstone; and (3) equally mixed brown and gray sandstones and shale. C. dentata sub-plots were planted within each of the six plots to serve as proxies for the blight-resistant chestnut hybrids. Preliminary data suggest that initial survival rates are significantly higher (100%) on the mixed spoil material over that of the weathered brown sandstone (79.5%). Survival on the un-weathered grey sandstone (93.2%) was not significantly different than that observed on the other two spoil types.

Establishment of Sweet Birch on Surface Mine Spoil as Influenced by Mycorrhizal Inoculation and Fertility

Abstract Induced mycorrhization of sweet birch (Betula lenta L.) by Pisolithus tinctorius (Pers.) Coker & Couch, as influenced by substrate fertility, was evaluated for its effects on seedling growth and physiology. Following a brief period in seed flats, seedlings were transplanted to mine spoil where they resided for 30 months, and three nutrition regimes were imposed throughout the study by application of differing nutrient solution concentrations. High fertility suppressed mycorrhizal formation by P. tinctorius but promoted that of other mycobionts. Pisolithus mycorrhization induced substantial aboveground and belowground growth as indicated by dimensions and mass for the former and mass and length for the latter but favoring root over shoot growth overall. Furthermore, these mycorrhizae were frequently able to compensate for the growth stimulation of higher nutrient additions. Measurements of xylem pressure potential and soil water potential indicated that water uptake was enhanced by P. tinctorius during simulated drought episodes of two durations and in subsequent recovery periods. Inoculated seedlings had higher foliar concentrations of critical nutrients, especially N, and lower concentrations of potentially phytotoxic metallic elements, particularly Mn, than uninoculated seedlings, although the latter response was absent in high fertility. Spoil analyses clearly revealed the influence of the nutrition regimes but also the effects of seedling uptake on substrate chemistry, and reinforced the findings of the foliar analysis concerning suppression of metal uptake by P. tinctorius. Collectively, these results suggest that P. tinctorius can provide sweet birch an array of physiological benefits that will permit this tree species to flourish on harsh substrates such as surface mine spoils without heavy application of chemical fertilizers.

Predictability of surface mine spoil hydrologic properties in the Appalachian Plateau.

Prevention of acid mine drainage at surface coal mines in the Appalachian region relies to an extent on minimizing ground water contact with acid-forming materials, and maximizing ground water contact with alkalinity-yielding materials. Acid-forming materials are often selectively handled to minimize or prevent contact with ground water. Controlling ground water contact with acidic or alkaline materials depends on forecasting the level and range of fluctuation of the postmining water table within the mine backfill. Physical measurements and aquifer testing of more than 120 wells from 18 reclaimed mines in Kentucky, Ohio, Pennsylvania, and West Virginia have led to improved forecasting of the postmining ground water system. Factors that influence the ground water regime include spoil lithology and particle size, age of reclamation, spoil thickness, distance from the final highwall, and pit floor dip angle and direction. Spoil hydraulic conductivity (K) exhibits a 95% confidence interval range of six orders of magnitude about a mean K of 1.7 x 10(-5) m/sec. Spoil aquifer saturated thickness is related to the overall thickness of the spoil, the lithology of the spoil, dip of the pit floor, and distance to the highwall. Saturated spoil thickness has a 95% confidence interval of 2.2 to 3.6 m about the mean of 2.9 m. The predicted saturated zone averages 19% of the total spoil thickness.

Nutrient availability in the initial stages of surface mine spoil reclamation — Impact on plant growth

The aim of this study was to characterise nutrient availability in the initial stages of reclamation and its impact on the growth of Secale multicaule L., the typical cover crop in newly established Pinus silvestris L. stands. A field experiment testing different levels of nutrient supply (N, P, K) was conducted on a carboniferous and a non-carboniferous sandy mine spoil representing typical mine spoils in the open-cast lignite mining district of Lower Lusatia. On both types of mine spoils, primarily N and P limited plant growth. On non-carboniferous mine spoil, low P availability to plants was alleviated by mineral fertiliser application while on carboniferous mine spoil, due to P immobilisation, P availability was still limiting plant growth after similar levels of P fertilisation. The elevated Nmin content in carboniferous mine spoil compared to non-carboniferous mine spoil is probably the result of less N leaching as the dominant N form in carboniferous mine spoil is NH4+ while the highly mobile NO3— is prevailing in the non-carboniferous mine spoil. N release from geogenic organic matter in carboniferous mine spoil as suggested by comparable Nt contents in pedogenetically formed soil organic matter is less likely. Nährstoffverfügbarkeit in Kippsubstraten in der Initialphase der Rekultivierung — Einfluß auf das Pflanzenwachstum Ziel der Untersuchungen war es, die Nährstoffverfügbarkeit im Anfangsstadium der Rekultivierung zu charakterisieren und ihre Bedeutung für das Wachstum von Secale multicaule L., das als Untersaat bei der Neuanlage von Kiefernaufforstungen (Pinus silvestris L.) verwendet wird, zu untersuchen. Zu diesem Zweck wurde ein Feldversuch mit verschiedenen Nährstoffversorgungsstufen (N, P, K) auf kohlehaltigem und kohlefreiem sandigem Kippsubstrat, welche charakteristisch für das Niederlausitzer Braunkohlerevier sind, angelegt. Auf beiden Kippsubstrat-Typen war das Pflanzenwachstum durch N und P limitiert. Im kohlefreien Kippsubstrat wurde die geringe P-Verfügbarkeit durch Mineraldüngung verbessert. Im kohlehaltigen Kippsubstrat war das Pflanzenwachstum aufgrund der P-Festlegung jedoch weiterhin durch niedrige P-Verfügbarkeit limitiert. Die erhöhten Nmin Gehalte im Kipp-Kohlesand im Vergleich zum Kipp-Sand sind wahrscheinlich das Ergebnis verringerter N-Auswaschung auf dem Kipp-Kohlesand. Hier bildet NH4+ den dominanten Anteil der mineralischen N Fraktion, während auf dem Kipp-Sand das hoch mobile NO3— dominiert. Eine N-Freisetzung aus der geogenen organischen Substanz im Kipp-Kohlesand, wie es vergleichbare Nt-Gehalte in pedogen gebildeter organischer Substanz vermuten ließen, ist wenig wahrscheinlich.

Establishment of kura clover and red clover on surface mine spoil and soil

ABSTRACT Field trials were conducted to study edaphic and seed treatment effects on stand establishment of kura clover (Trifolium ambiguum Bieb.) compared with red clover (T. pratense L.) on surface mine spoil and undisturbed soil. Scarified kura clover seed were either left uncoated, coated with a commercial seed treatment, or coated and treated with a fungicide. Site effects on seedling stand density were small. Maximum red and kura clover stand densities near 60 and 30 plants m−1 of row, respectively, represented 53% and 33% of the germinable seed planted. In June following seeding, shoot mass of red clover was 13.6 and 4.1 times greater than that of kura clover on soil and mine spoil, respectively. Seed coating effects were small. One-yr-old kura clover plants from the soil site had greater root, crown and total plant mass plant−1 than red clover but the opposite was true on mine spoil. The consistency of reduced seedling densities for kura compared with red clover suggests that higher seeding rates might be warranted. Reduced above-ground seedling growth of kura clover is associated with greater weight accumulation in below-ground rhizome tissues compared with red clover.

APPLICATION OF GEOCHEMICAL MODELING AND HYDROLOGIC TECHNIQUES TO INTERPRET SOURCES, MIXING AND EVOLUTION OF MINE DRAINAGE

The geochemical code PHREEQC was used in an investigation of potential recharge sources to a flooded pit affected by acid drainage. Pit water quality had been alkaline with low metals and moderate dissolved aluminum, manganese and sulfate. The recharge area for the flooded pit included a coal refuse pile, flooded underground mine works, flyash pile, surface mine spoil and a sediment pond. A set of water quality samples were analyzed for mine drainage parameters, major dissolved constituents and some trace metals. These data were inverse modeled using the flooded pit water as the end product. Mixing of several possible sources and single source recharge scenarios were run along the inferred ground water flow path. Mixing of coal refuse pile leachate with leakage from the sediment pond or mine spoil provided acceptable characterization as the principal sources controlling pit water chemistry. These results were consistent with the ground water flow path interpreted from water level measurements in wells, structure, air photos and mining history. The dominant rock-water interactions modeled were dissolution of carbonate minerals and stored sulfate salts. Simple binary mixing was not adequate to describe the reaction path and resultant water chemistry. Geochemical models were useful for assessing mine drainagemore » sources, and can be included as one of a collection of investigative tools.« less

U.S. DEPARTMENT OF ENERGY PROJECTS INVOLVING THE USE OF COAL COMBUSTION BYPRODUCTS IN MINING APPLICATIONS

The onset of utility deregulation now makes it apparent that coal combustion by-product (CCB) utilization is one key area that may help utilities better manage their available resources. Because current utilization rates of CCB's are relatively low, the US Department of Energy is actively co-sponsoring a variety of CCB utilization projects, along with projects that seek to characterize the by-products resulting from newly-developed technologies for coal combustion, gasification, or flue gas cleanup. Mining applications represent a potential high-volume market for CCB's, with beneficial uses that include the prevention or control of acid mine drainage, surface subsidence over underground mines, and reclamation of acidic surface mine spoils. Future applications may include the development of CCB-based construction materials for use in mining and the selective backfilling of CCB's to increase underground coal mine extraction rates. The goal of these projects is to demonstrate that CCB's are of significant value when used in mining applications, and that CCB utilization in mines represents more than just a cheaper alternative to landfill disposal.

Evaluating shredded rubber tires and sewer sludge as surface mine spoil amendments

ABSTRACT Shredded rubber tires and composted sewer sludge were evaluated and compared as spoil amendments on an abandoned mine site in western Kentucky. Percent ground cover was measured in early spring and early summer of the third year to determine treatment effects. Significant treatment effects did not appear until the summer measurement, and the combination of rubber tire mulch and incorporated sewer sludge was found to be the most effective in promoting site revegetation. There was a significant decline in percent live grass ground cover as the growing season progressed, indicating that early season measurements may not be adequate for estimating revegetation effectiveness.

Temporal Variation of Soil Hydraulic Properties on Municipal Solid Waste Amended Mine Soils

Composted municipal solid waste (MSW) was applied to reclaimed surface mine spoil to quantify the impacts on the saturated hydraulic conductivity, bulk density, soil water retention, and sorptivity in the surface soil. Treatment levels of 14.0 and 28.0 Mg/ha were incorporated to approximately 130 mm on a relatively flat 0.93-ha site in eastern Kentucky. The logarithm of hydraulic conductivity increased from log(8.45 ¥ 10–8 m/s) to log(3.58 ¥ 10–6 m/s) and the bulk density decreased from 1.74 to 1.49 Mg/m3. For hydraulic conductivity results to be meaningful, hydraulic conductivity data should be transformed logarithmically prior to any statistical operation, including averaging. There was no significant difference in any parameter between the two treatment levels. Linear time variations over the three- year study were significant for the bulk density and for soil water retention, both of which decreased with time. A seasonal variation, which was statistically significant over some growing seasons and not others, occurred in hydraulic conductivity, bulk density, and soil water retention.

A simple, effective method for determining the bulk density of stony soils

Abstract A new technique of determining bulk density based upon the excavation method is especially useful in stony soils and surface mine spoils. The technique involves determining the volume of an excavated hole using an expanding urethane foam which solidifies to form a perfect cast of the hole. Volume of the cast is determined by water displacement. Comparison of this method with the sand method of volume determination in a surface mine spoil showed no difference in calculated values of bulk density. However, bulk densities determined by driving a steel core of known volume into the stony surface mine spoil were consistently 12–17% lower than those determined by excavation. The new technique may be applied to sloping soil surfaces and may be used for bulk density determinations at depth in the exposed vertical face of a soil pit.

Mineralization potential in surface minespoils of the labile and recalcitrant fractions of 14C-labelled timothy ( Phleum pratense) litter

It has been shown that values of labile and recalcitrant litter fraction sizes based on benzene-alcohol extractions were not different from those values predicted from field data as described by a double exponential model. In the present study, the portion of timothy litter that was soluble in benzene-alcohol was used to represent the labile litter fraction and the portion that was insoluble (ligno-cellulose) was used to represent the recalcitrant litter fraction. Mineralization of 14C-labelled timothy litter in reclaimed and non-reclaimed surface coal minespoil in Alberta, Canada, was examined under optimum moisture and temperature conditions. Daily measurements of [ 14C]CO 2 during a 35-day period were fitted to a single exponential model for both the labile and recalcitrant litter fractions. Decay constants derived from the single exponential models were used as mineralization potential indices of the soil microbial communities utilizing the two litter fractions. The microbial communities in all soils tested had similar potentials to decompose the labile fraction of timothy litter. The ability of the microbial community to decompose the recalcitrant litter fraction was higher in segregated topsoil (topsoil that was shaved from the land prior to open pit excavation, stockpiled for 6 months and spread as a soil base) than it was in newly reclaimed overburden (a mixture of topsoil, regolith and hydroseed mulch). The ability to decompose the recalcitrant litter fraction in reclaimed overburden slowly increased during a 4-yr period to a potential similar to that in segregated topsoil. The potential of the soil microbial community to decompose the labile litter fraction was not affected by spoil factors, whereas the potential to decompose the recalcitrant litter fraction was influenced in decreasing order by soil microbial biomass, soil organic matter and soil N.

Sediment Yield and Water Quality from a Steep-Slope Surface Mine Spoil

ABSTRACT SEDIMENT yield and storm runoff water quality from a steep-slope, back-to-contour, coal surface mining spoil in the New River Basin of Tennessee were monitored for a period of three years. Sediment and mineral constituent concentrations observed in storm runoff from the spoil increased to a maximum 1.1 to 1.3 years following the completion of mining, then declined. This increase was associated with the loss of mulch provided at reclamation and the onset of rill and gully erosion. Maximum sediment yield also occurred within this period. By the end of the third (3rd) year following mining, a dense and uniform vegetative cover had become established on the spoil. Sediment, iron, and manganese concentrations decreased to premining levels and met Federal mine effluent standards. Calcium and magnesium concentrations, however, remained elevated above premining levels indicating chemical weathering of the spoil surface continued after sediment production had subsided. The runoff studied is non-acid..

Humic matter enrichment in reclaimed soils under semiarid conditions

Abstract Changes in humic matter of overburden and replaced topsoils receiving four different treatment combinations of fertilizer and an organic amendment were investigated on reclaimed surface mine spoil in southeastern Montana. Nine years after revegetation, the maximum increases of organic matter and humic acid content, respectively, were 53% and 23% on overburden soils and 14% and 16% on replaced topsoils. The C:N ratio increased in the overburden soil from 11.0 to 13.5 with treatments; in the topsoil the C:N ratio changes were variable. C:N ratios of 9–11 were characteristic of humic acids, with no consistent relation to treatments. The increases in the soil organic matter, humic matter, and total soil nitrogen content were greater than the amounts of C and N added as amendments, probably because of the increased plant litter availability and retention in soil and possible nitrogen input by dinitrogen fixation.

Characterizing Unsaturated Hydraulic Conductivity of Western Kentucky Surface Mine Spoils and Soils

AbstractA large‐scale laboratory infiltrometer system was used to determine infiltration characteristics of “reconstructed” surface mine spoil and soil horizons. Soil water characteristic curves were determined using the Brooks‐Corey and the Gardner procedures and developed based on desorption tensiometer data. Unsaturated hydraulic conductivity values were determined using the “plane of zero flux” procedure and compared with predictions resulting from models described by Campbell, Burdine, and Mualem for situations involving reconstructed soil and spoil materials. There was generally good agreement between the models and excellent agreement between Campbell's predictions and plane of zero flux results. Both the Gardner equation and the Brooks‐Corey equation gave good estimates of the soil water characteristic curves for the materials. The physical significance of the parameters θr and ψe, when determined by statistical procedures, appears very questionable. In this study, the final steady‐state infiltration rate appeared to be a good estimate of the hydraulic conductivity at apparent saturation.

Environmental effects of slaking of surface mine spoils: Eastern and central United States : Andrews, D E; Withiam, J L; Perry, E F US Bureau of Mines report OFR 146-80, Sept 1980, 250P

Environmental effects of slaking of surface mine spoils: Eastern and central United States : Andrews, D E; Withiam, J L; Perry, E F US Bureau of Mines report OFR 146-80, Sept 1980, 250P

Establishing European Alder Seedlings in Fescue-Covered Surface Mine Spoil

Abstract European alder (Alnus glutinosa L.) seedlings were planted in an established ground cover of Kentucky-31 fescue (Festuca arundinacea Schreb.) of surface mine spoil in southeastern Kentucky. The effects of the ground cover on seedling survival, height, dry weight production, soil moisture and temperature, leaf water potential, and diffusion resistance, were observed and evaluated. Three treatments, scalping, clipping, and paraquat herbicide, to reduce competition around individual tree seedlings, were evaluated. Highest survival (43 percent) occurred in plots where competing vegetation was mechanically scalped away from seedlings. Scalping increased the soil moisture available for growth and reduced water stress of seedlings.