Reclaimed Mine Spoil Research Articles

Functions of microarthropods in reclaimed mines spoil: A case study of Kathara Coalfield area of Jharkhand,India

Reclaimed mines spoil (RMS) is the byproduct of open-cast mining and an ecological footprint under twin stresses namely, anthropogenic and natural. The present paper measures the stresses in reclaimed coal mine spoils and has two sections – the first dealing with the experiments and their results, while the second section derives an ecological model from the experiment. An experiment was carried out (experimental years, 2006 – 2008) in reclaimed coal mine spoils (RMS) of Jharkhand. Four RMSs of different chrono sequences of plantations on the overburden dumps (OBD) were considered for the study. Data on soil arthropods along with other physical parameters were collected from a 1meter x 1meter grid of quadrate periodically. It was observed that the Shannon diversity index of younger RMS was higher than the 15- and 30-year-old RMS. Old age sites and forests had a higher Diversity Index. Simpson’s index was 0.0877, 0.889, 0.869, and 0.887 in four RMS sites, and 0.885, and 0.917 in the forest. Organisms in degraded systems are initially rudrals – create a functional system and establish as K-select species. It was observed that the system has stresses – homeostatic processes that keep a system in its original state, and other forces – resilience pulls them out of the status quo but in reclaimed mine spoils an additional force anthropogenic activities work synergistically with the forces of resilience that push the system towards non-equilibrium, which is critical for succession and ecesis. Based on findings and functional stresses in the system an ecological model was developed for ecesis that is operative in the system.

Invasive weed‐based biochar facilitated the restoration of coal mine degraded land by modulating the enzyme activity and carbon sequestration

Excessive growth of invasive weeds in reclaimed coal mine sites are undesirable as they compete for nutrient with the planted species. To overcome this problem, these invasive species may be converted to biochar and used as an amendment during reclamation. Objectives of the present study are to prepare biochar from invasive weeds and apply as amendment in an 8‐year‐old reclaimed mine spoil (RMS) and study the changes in spoil physio‐chemical properties, enzymatic activity, and C‐stock. Biochar was prepared at 450°C and applied at 10 t/ha (BC10) and 20 t/ha (BC20) in field condition. The result showed that biochar ameliorates RMS physio‐chemical properties significantly with respect to moisture content (+27%), available‐N (+3%), exchangeable‐K (+15%), and cation exchange capacity (+35%) in BC20 compared to control. Geometric mean of enzymatic activities index increase in BC10 (8) and BC20 (10.2) compared to control (5.8) indicating improved microbial activities. BC20 had significantly high recalcitrant carbon, which indicates higher C‐sequestration potential by biochar application. Additionally, the total C‐stock increased by 13 and 91% at BC10 and BC20, respectively. CO2 sequestered increased by 13% at BC10 and 91% at BC20 amendment. In‐situ production and surface application of biochar at 20 t/ha will cost 239 USD/ha. The study concluded that invasive weed biochar has the potential to improve the spoil nutritional properties (N & K), increase C‐stock and C‐sequestration potential in coal mine spoil.

Eco-Restoration of Coal Mine Spoil: Biochar Application and Carbon Sequestration for Achieving UN Sustainable Development Goals 13 and 15

Open cast coal mining causes complete loss of carbon sink due to the destruction of vegetation and soil structure. In order to offset the destruction and to increase sequestration of carbon, afforestation is widely used to restore these mine spoils. The current field study was conducted to assess the ecosystem status, soil quality and C pool in an 8 years old reclaimed mine spoil (RMS), compared to a reference forest (RF) site and unamended mine spoil (UMS). Biochar (BC) prepared from invasive weed Calotropis procera was applied in this 8 year RMS at 30 t ha−1 (BC30) and 60 t ha−1 (BC60) to study its impact on RMS properties and C pool. Carbon fractionation was also conducted to estimate inorganic, coal and biogenic carbon pools. The C stock of 8 year old RMS was 30.98 Mg C ha−1 and sequestered 113.69 Mg C ha−1 CO2. BC30 and BC60 improved the C-stock of RMS by 31% and 45%, respectively, and increased the recalcitrant carbon by 65% (BC30) and 67% (BC60). Spoil physio-chemical properties such as pH, cation exchange capacity, moisture content and bulk density were improved by biochar application. The total soil carbon at BC30 (36.3 g C kg−1) and BC60 (40 g C kg−1) was found to be significantly high compared to RMS (21 g C kg−1) and comparable to RF (33 g C kg−1). Thus, eco-restoration of coal mine spoil and biochar application can be effective tools for coal mine reclamation and can help in achieving the UN sustainable development goal 13 (climate action) by increasing carbon sequestration and 15 (biodiversity protection) by promoting ecosystem development.

Effects of fertilization and straw return methods on the soil carbon pool and CO2 emission in a reclaimed mine spoil in Shanxi Province, China

Reclaimed soil is similar to an “empty cup” with a large carbon (C) sequestration potential. Agricultural management practices strongly influence C storage and soil carbon dioxide (CO2) emission. The objective of this study was to identify the effects of fertilization and straw return methods on the soil C pool and CO2 emission in a reclaimed mine spoil. Thus, we studied the effects of four fertilization treatments [chemical fertilizer (NP), manure (M), 50% M plus 50% NP (NPM), and unfertilized control (CK)] and three straw return methods [no straw return (no straw), return of straw mixed with soil (straw mixing), and return of straw to the surface of the soil (straw mulching)] in a mine reclamation region by examining changes in the soil C pool and CO2 emission. The soil C pool was evaluated by acid hydrolysis, considering three pools: (a) labile pool I (LP I), obtained by hydrolysis with 5 N H2SO4 at 105 °C for 30 min; (b) labile pool II (LP II), obtained by hydrolysis with 26 N H2SO4 at room temperature overnight, followed by 2 N H2SO4 at 105 °C for 3 h; and (c) the recalcitrant pool, measured as the unhydrolyzed residue. The CO2 emission/C sequestration and CO2 emission/grain yield ratios were used as indicators of C emission. Compared with the CK, the NPM treatment was the most efficient among the fertilization treatments in increasing grain yield (136%) and C sequestration (311%) and reducing the CO2 emission/C sequestration (62%) and CO2 emission/grain yield (32%) ratios. The straw mixing treatment had more soil organic carbon (SOC), a larger LP I and LP II, and more C sequestration than the other straw return treatments. The addition of manure resulted in a higher distribution rate of new organic C to the labile C pool (73–78%) than the addition of inorganic fertilizer (45%). Soil C emissions were mainly concentrated in the maize growing season, accounting for more than 80% of the total annual C emissions. LP I, LP II and CO2 emission were significantly positive correlated with SOC and yield. Therefore, soil C pools and CO2 emissions are significantly influenced by fertilization regimes and straw return methods, which should be used to important indicators to estimate the C balance in agro-ecosystems during the process of mine spoil reclamation.

Canopy tree species determine herb layer biomass and species composition on a reclaimed mine spoil heap

According facilitative models of succession, trees are great forest ecosystem engineers. The strength of tree stand influences on habitat were tested in rather homogenous conditions where heterogeneity of site condition was not an important influence. We hypothesized that canopy composition affects total aboveground vascular herb layer biomass (THB) and species composition of herb layer plant biomass (SCHB) more significantly than primary soil fertility or slope exposure. The study was conducted in 227 randomly selected research plots in seven types of forest stands: pure with Alnus glutinosa, Betula pendula, Pinus sylvestris, Quercus petraea and Robinia pseudoacacia, and mixed with dominance of Acer pseudoplatanus or Betula pendula located on hilltop and northern, eastern, western, and southern slopes on a reclaimed, afforested post-mining spoil heap of the Bełchatów Brown Coal Mine (Poland). Generalized linear models (GLZ) showed that tree stand species were the best predictors of THB. Non-parametric variance tests showed significantly higher (nearly four times) THB under canopies of A. glutinosa, R. pseudoacacia, B. pendula and Q. petraea, compared to the lowest THB found under canopies of P. sylvestris and mixed with A. pseudoplatanus. Redundancy Analysis (RDA) showed that SCHB was significantly differentiated along gradients of light-nutrient herb layer species requirements. RDA and non-parametric variance tests showed that SCHB under canopies of A. glutinosa, R. pseudoacacia and mixed with A. pseudoplatanus had large shares of nitrophilous ruderal species (32%, 31% and 11%, respectively), whereas SCHB under B. pendula, Q. petraea, mixed with B. pendula and P. sylvestris were dominated by light-demanding meadow (49%, 51%, 51% and 36%, respectively) and Poaceae species. The results indicated the dominant role of tree stand composition in habitat-forming processes, and although primary site properties had minor importance, they were also modified by tree stand species.

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.

Carbon storage in coal mine spoil by Dalbergia sissoo Roxb.

Terrestrial carbon storage in the form of biomass and soil organic carbon stock is one of the important tools to combat climate change. Carbon sequestration by trees on coal mine spoil is of significance in view of the huge quantities of carbon emission associated with energy extraction from coal. Dalbergia sissoo is one of the timber yielding trees normally used for reclamation of mine spoil. Biomass and soil organic carbon stocks under D. sissoo growing on different aged (2 to 16years) coal mine spoils were evaluated. Tree height, diameter at breast height, and biomass weight of D. sissoo increased with age of reclamation. Biomass carbon stock of 16years old D. sissoo in reclaimed mine spoil amounts to 50.8t/ha, which is about 80% of a similar stand in forest ecosystem. In line with biomass C stock, soil organic carbon stock also increased with time (1.19t/ha in 2years to 9.82t/ha in 16years). Biomass carbon stock increased exponentially with time, whereas soil organic carbon stock increased linearly. A sharp increase in biomass C stock was observed after 10years of reclamation. Chemical analysis and pyrolysis data showed that D. sissoo leaf litter and other plant parts could significantly contribute to soil carbon stock. Establishment of D. sissoo on the mine spoils augmented the soil carbon stock and ameliorated physical, chemical and biological parameters of the mine spoil. These improvements in the soil quality parameters could further enhance the biomass productivity. Principal component analysis revealed that soil organic C, microbial biomass carbon and available nutrients are key factors influencing the overall quality of the mine spoil and biomass carbon stock. Thus, while reclaiming mine spoils, management practices could be focused to improve soil organic C and nutrients.

Geochemical background of potentially toxic trace elements in reclaimed soils of the abandoned pyrite–uranium mine (south-central Poland)

Spatial distribution patterns of As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, U and Zn were determined in topsoil samples collected after 40 years of chemical remediation conducted in the inoperative “Staszic” pyrite–uranium mine in the Holy Cross Mountains, south-central Poland. Soil samples were taken from 58 sites using a systematic random sampling design. Selected samples were subjected to an X-ray diffractometry analysis on bulk soils and separated clay fractions. Hematite, goethite and gypsum are common mineral phases in soil samples. Technogenic soils developed on reclaimed mine spoils show uniform spatial element distribution patterns and additionally a distinct enrichment in As, Pb, Mn, U and Zn. Mineral and chemical composition of soils vs. rocks points to the lithogenic source of the determined elements. The results of chemical analysis have been used for evaluation of geochemical background of trace elements in the study area with the iterative 2σ-technique. This investigation shows that using mean crustal element concentrations (Clarke values) as proxies of threshold values in soils are not useful for determination of strongly positive geochemical anomalies. A modified enrichment factor, i.e. a local enrichment factor, is proposed for identification of sites where soils are contaminated.

Rhizosphere soil indicators for carbon sequestration in a reclaimed coal mine spoil

Re-vegetation of mine spoil enhances carbon storage in both above-ground plant biomass and mine soil. The current study was conducted at the coalmine overburden dumps of Jharia Coalfield (India), with the aim to evaluate the effect of different tree species on the rhizosphere soil properties and to identify key rhizosphere soil indicators that influence tree biomass and carbon density. Rhizosphere soil samples were collected from five tree species (Acacia auriculiformis, Albizia lebbeck, Cassia siamea, Delonix regia, and Dalbergia sissoo) of the same age. An area without ground vegetation was selected as a non-rhizosphere soil. The carbon density was higher for D. sissoo and A. auriculiformis (39.6–43.7kg C/tree) and lowest for A. lebbeck (20.7kg C/tree). Except for C. siamea (4.38%), the total C (TC) content was lower in the rhizosphere than the non-rhizosphere soil. About 50% reduction in TC was observed for A. auriculiformis and A. lebbeck and 75% for D. sissoo. Labile C and microbial biomass carbon (MBC) were significantly higher in the rhizosphere than the non-rhizosphere soil. Dehydrogenase enzyme activity was higher in all the rhizosphere soils with the maximum activity under C. siamea (88.48μg/TPF/g/24h) and D. sissoo (71.95μg/TPF/g/24h). Three types of carbon accumulation indices (CAI) were calculated: CAI-1, based on TC and labile C; CAI-2, TC, and MBC; and CAI-3, TC, labile C, and MBC. CAIs depending on rhizosphere effect were generally higher for D. sissoo and C. siamea. Principal component analysis showed that the tree carbon density is closely associated with CAI-3, CAI-2, carbon lability index (CLI), available N, and MBC. Thus, an integrated rhizosphere carbon accumulation index (CAI-3, based on rhizosphere effects) and N could be considered as indicators for carbon sequestration in reclaimed mine spoils.

Spatial autocorrelation of soil CO2 fluxes on reclaimed mine land

Recent evidence has shown that CO2 emissions from reclaimed mine soil with acid mine drainage and carbonate material is an emerging geohazard. Surface CO2 flux measurements can be a cheap and effective way to delineate such hazards and avoid residential and commercial real-estate development on high-risk zones. Very little work has been done to ascertain whether or not such fluxes are spatially correlated, which has significant implications on the choice of statistical methods for analysis. The objective of this study was to understand the extent to which CO2 fluxes on a reclaimed mine spoil, with CO2 from carbonate neutralization of acidic drainage, are spatially autocorrelated. CO2 fluxes from three reclaimed surface coal mine sites were measured and used in statistical analysis to test the research hypothesis. The results show that the spatial variability of fluxes is not always random but can show significant (p < 0.0001) spatial autocorrelation. This result implies that classical statistical analysis of CO2 fluxes from reclaimed mine land may lead to wrong inferences, since such analysis ignores the spatial correlation. It appears spatial autocorrelation in CO2 fluxes may be related to spatial autocorrelation in soil temperatures, suggesting a common underlying phenomenon. Significant contribution of CO2 from exothermic acid mine drainage to soil CO2 flux is suggested as a possible explanation.

Evaluation of the Soil Quality on the Reclaimed Lignite Mine Land in West Macedonia, Greece

The West Macedonia Lignite Centre (WMLC) is a complex of surface mines that produces annually 45 Mt of lignite and excavates more than 280 Mm3 of earthy materials. After 60 years of operation, WMLC occupies 16,000ha. Up to now, 4,000ha of mine spoils have been reclaimed; sloped surfaces have been reforested and horizontal surfaces are rented as farmland. Based on the environmental permits that are in force, WMLC conducts systematically soil sampling and lab analyses for determining quality characteristics of reclaimed soils that concern both soil fertility and contamination control.According to the results of lab analyses carried out so far, reclaimed soils are characterized by an alkaline pH and normal electrical conductivity values. Their particle size distribution classifies them from moderately coarse to fine soils. A large number of samples exhibit high CaCO3 content, while organic matter content is high in samples collected from reclaimed mine spoils where lignite seams of low calorific value have been dumped. Cation exchange capacity is high, mainly due to high concentrations of iron in assimilable form.Regarding the concentrations of nutrients, these exhibit a wide variation depending on the element and sampling depth. Sufficient concentrations of the exchangeable cations K+, Ca2+ and Mg2+ have been determined in the majority of the soil samples. Phosphorus concentrations are below the generally accepted availability level of 20mg/kg.Heavy metals concentrations are below the screening values determined by the Dutch Soil Pollution Act with the exception of Nickel, which often exhibits concentrations higher than the intervention value of 210mg/kg. Chromium concentrations are also high but do not exceed the intervention value of 380mg/kg. Iron is the only metal that exhibits systematically higher concentrations in soil samples collected from the reclaimed mine spoils than in soil samples collected from areas of West Macedonia region that have not been disturbed by lignite mining operations.

Modeling of Water Flow in Reclaimed Mine Spoil with Embedded Lignitic Fragments Using Hydrus-1D

Lignitic mine soils represent a dual-porosity medium consisting of a technogenic mixture of overburden sediments that include porous fragments embedded within a mostly coarse-textured matrix. Flow and transport process in such soils are not sufficiently understood. The objective of this study was to identify the most appropriate conceptual model for describing small-scale heterogeneity effects on flow based on the physical structure of the system. HYDRUS-1D was used to simulate water flow under field conditions. We compared a dual-porosity (mobile–immobile) model simulation of the field soil water with field monitoring results. The predicted and observed water content were in good agreement. Since the heterogeneity of the lignitic mine soil may lead to preferential flow, Coomassie brilliant blue dyes were applied to the reclaimed surface, revealing preferred flow paths through macro-pores surrounding the numerous, large rock fragments.

Assessment of Robinia pseudoacacia cultivations as a restoration strategy for reclaimed mine spoil heaps

Reforestation with black locust (Robinia pseudoacacia) is considered a successful technique that is often used for the reclamation of open-cast mine areas. An alternative reclamation technique could be the natural regeneration of vegetation with spontaneous grass species. In this study, we compared the concentrations of chemical and biochemical variables in soil samples taken under black locust canopy to those from sites covered by spontaneous grass vegetation (control samples) in a time sequence of spoil deposition (0-10years), in order to assess which of the two reclamation techniques yields higher soil quality. Soil quality refers here to the ability of soils to function ecologically. This has a special interest since the main question for the restored soils is their capacity to perform a range of ecological functions under stress or disturbance. Furthermore, we aimed at identifying the effect of vegetation type on soil ecological succession. The effect of vegetation type on primary succession becomes apparent after 2years of reclamation. R. pseudoacacia as a nitrogen-fixing plant enriched soil with organic and inorganic nitrogen and organic matter to a greater extent than the natural grasses. It also increased the amount of soil microbial biomass and the activity of alkaline phosphatase. However, the fact that black locust failed to enhance dehydrogenase activity and actually decreased the activity of urease, activities that represent specialized niche functions and therefore, are more vulnerable to stress or disturbance, suggests that the development of an indigenous grass community in combination with organic supplements might often be more appropriate for the reclamation of similar kinds of mine areas.

Mineralisation and humification of plant matter in soil samples as a tool in the testing of soil quality

Since life is inevitably dependent on the assimilation and dissimilation of carbon, and since most of the organic carbon is bound in soil humic matter, the mineralisation and humification of plant carbon in soil should be monitored, so as to evaluate soil quality and avoid ecological risks. For this reason we suggested an incubation test of thirty days in duration with soil samples amended or not with lucerne meal as a source of plant carbon. During the incubation period, CO2 release is to be measured repeatedly, and thereafter contents of humic acids (HA) and fulvic acids (FA) should be estimated and compared with those determined in the original soil samples. Our results obtained with samples from non-fertilized or long-term ( > 40 years) fertilized plots of two field trials indicate that fertilization by NPK + farm yard manure resulted in (i) a slight enhancement of C mineralisation, i.e., CO2 release from soil, and (ii) a significant increases of HA and FA contents. Soil samples from a reclaimed mine spoil, and either fertilised or not with sewage sludge did not show distinct differences in the same parameters. The practicability of the incubation test as a tool in the monitoring of soil quality should be further proved using samples from differently affected soils.

English

Human disturbed landscapes such as those in early stages of mine reclamation provide habitat for disturbance-oriented species. Disturbance- oriented birds that are uncommon or absent from the surrounding region may be concentrated at large-scale human disturbed sites such as surface mines. Implications for conservation and management of such species are important considerations, given the possibility one or more of those species may be federally protected. Recent expansion of the breeding range of Interior Least Terns (Sterna antillarum athalassos), a federally endangered species, in Texas has many implications for management on private lands. Interior Least Terns first nested on reclaimed mine spoil at Big Brown Mine in East-Central Texas in 1997. Management objectives for reclamation planning were subsequently established to provide suitable nesting and foraging habitat for terns while seeking to reduce the risk of interference with mining activities at Big Brown Mine. Since 1997, an average of 29 nests per year have occurred on artificial sites created for tern nesting, with average annual nest success 49%, hatching success 47%, and fledging success 46%. Average annual reproductive success (fledglings per female) is 0.40. We discuss colonization of reclaimed mine land by disturbance- oriented avian species and present research on the nesting and foraging ecology of Interior Least Terns in Texas as a case study. Implications for conservation and management of disturbance-oriented birds in reclamation are discussed.

Bacterial functional redundancy along a soil reclamation gradient.

A strategy to measure bacterial functional redundancy was developed and tested with soils collected along a soil reclamation gradient by determining the richness and diversity of bacterial groups capable of in situ growth on selected carbon substrates. Soil cores were collected from four sites along a transect from the Jamari tin mine site in the Jamari National Forest, Rondonia, RO, Brazil: denuded mine spoil, soil from below the canopy of invading pioneer trees, revegetated soil under new growth on the forest edge, and the forest floor of an adjacent preserved forest. Bacterial population responses were analyzed by amending these soil samples with individual carbon substrates in the presence of bromodeoxyuridine (BrdU). BrdU-labeled DNA was then subjected to a 16S-23S rRNA intergenic analysis to depict the actively growing bacteria from each site. The number and diversity of bacterial groups responding to four carbon substrates (L-serine, L-threonine, sodium citrate, and alpha-lactose hydrate) increased along the reclamation-vegetation gradient such that the preserved forest soil samples contained the highest functional redundancy for each substrate. These data suggest that bacterial functional redundancy increases in relation to the regrowth of plant communities and may therefore represent an important aspect of the restoration of soil biological functionality to reclaimed mine spoils. They also suggest that bacterial functional redundancy may be a useful indicator of soil quality and ecosystem functioning.

Ground beetle communities on reclaimed mine spoil: Effects of organic matter application and revegetation

On a study site in the Lusatian lignite mining region (Germany), sandy mine spoil was ameliorated with either sewage sludge, compost or mineral fertilizer. Plots were sown with the grass Secale multicaule and planted with pine seedlings except for a control that was not meliorated and not revegetated. Pitfall catches of ground beetles in 1996/97 yielded high numbers of species and individuals directly after revegetation. The dominant beetles were xerophilic species, known to prefer open sandy sites. Catches in different plots were positively correlated with the amount of vegetation cover and declined as follows: amelioration with sewage sludge > compost > mineral fertilizer > untreated control. Even beetles characteristic of open sandy sites showed a distinct preference for plots with high vegetation cover treated with organic waste. For the dominant species, an attraction to shelter and a more balanced, humid microclimate is assumed. A year-to-year comparison showed an increase in beetles typical of dry grasslands and ruderal sites in the second year, while characteristic species of open sandy sites decreased. Application of organic waste combined with revegetation led to an immediate increase in beetle numbers. In the long term, revegetation would be expected to reduce suitable habitats for endangered ground beetles which prefer open sites with poor sandy soils.

Preliminary investigations of the status of soil inhabitants in reclaimed mine spoils: V. Bhatt, P. Soni, H. B. Vasistha & O. Kumar, Journal of Nature Conservation (Muzaffarnagar), 3(1), 1991, pp 10–19

Preliminary investigations of the status of soil inhabitants in reclaimed mine spoils: V. Bhatt, P. Soni, H. B. Vasistha & O. Kumar, Journal of Nature Conservation (Muzaffarnagar), 3(1), 1991, pp 10–19

Establishing Commercial Pine Forest on Mine Soils

At Dolet Hills Mining Venture eighty-eight percent of the reclaimed mine spoil will be returned to commercial pine forest. Common bermuda grass is established prior to the planting of pine seedlings in order to control erosion of the overburden material. Although this is an effective means of erosion control it creates sever competition with the pine seedlings when they are planted. To reduce this competition Oust/Velpar is applied in four foot bans after the trees have been planted. The Oust/Velpar is applied at a rate of 6 oc/acre Oust and 1 pint/ac. Velpar on sandy soils. On clay soils it is applied at a rate of 6 oz/ac. Oust and 2 pint/acre Velpar. The ban application allows for control of competition around the new seedlings yet leaves a healthy stand of common bermuda grasses between rows to control erosion. Additional key words: Oust/Velpar, four foot ban, sandy soils, clay soils.

A Study of Acid Mine Drainage Using Earth Resistivity Measurements

AbstractA resistivity survey was conducted in a reclaimed mine spoils disposal site near Wheatland, Indiana to study the ground‐water contamination. Due to the high conductivity of the acidic leachate from coal refuse, it was possible to detect the valleys in which this material was dumped (gob valleys) by using the horizontal resistivity profiling technique. The thickness of the gob valleys and information about the stratigraphy of the site were obtained by using the vertical electrical sounding (VES) technique. The VES data for sounding points located near monitoring wells, together with the chemical analyses of water samples taken from these wells, were used to obtain an empirical relationship between the inferred earth resistivity and the amount of Total Dissolved Solids (TDS) in the ground water. The horizontal resistivity profiling data and the VES data at a 30‐ft electrode spacing were contoured. The resulting isoresistivity map, together with the empirical relationship, can be used to predict the approximate TDS concentration at a depth of approximately 30 ft at any point on the Wheatland site.