Sustainable rehabilitation can be compromised by the inability of vegetation to survive in hostile mine wastes on a long-term basis. The adverse chemical and physical properties of mine wastes, together with extreme pH conditions and lack of nutrients, provide poor growth conditions for vegetation during seed development and germination. This raises concern for the long-term survival of vegetation through means of seed production when under stress from the punitive properties of mine wastes. Seed vigour is a function of a variety of factors to which the parent plant is subjected during seed formation and maturation. Environmental conditions experienced by the maternal plant during the growth season plays a significant role in determining subsequent germination rates in seeds. Traits of offspring seed depend on the abiotic environment attributed by the growth medium during seed development and maturation The general aim of this study was to determine the viability of seed produced by a previous generation of grass species established in eight different mine wastes and two soils (namely: gypsum wastes; gold tailings with low pyrite content; gold tailings with high pyrite content; platinum tailings; kimberlite mine waste; fluorspar mine waste; andalusite mine waste; coal discard; red soil; and vertic soil) in order to identify suitable species for specific mine wastes to ensure long-term survival through means of seed production. The species selected included: Eragrostis curvula; Eragrostis tef; Cenchrus ciliaris; Eragrostis curvula; Digitaria eriantha; Cynodon dactylon; Chloris gayana; Hyparrhenia hirta; and Sorghum bicolor. The progeny seed‟s viability and ability to germinate were determined through a pot trial study and additional germination testing at the laboratory of Advance Seed (Pty) Ltd. (AS). The germination results were correlated with the growth media analyses by statistical non-parametric correlations which indicated several significant correlations among the growth media properties themselves, and with the germination of the progeny seed. C. gayana (Rhodes grass) seed had poor germination percentages, especially seed harvested from Rhodes grass grown in acidic wastes. Seed harvested from each of the E. curvula grasses grown in various mine wastes, had excellent germination percentages. According to the Repeated Measures ANOVA statistical analysis, there was a significant influence of the growth media in which the parent grass were grown as a variable on the germination of the progeny seed batches from S. bicolor, C. ciliaris, C. gayana, and D. eriantha, indicating that the environmental factors as attributed by the growth media, i.e. the eight different mine waste materials and two soils, and experienced by the maternal plant, did indeed influence the germination of progeny seed. However, it was found that significant correlations between the properties of the growth media and the germination of the progeny seed, was species dependent. The second general aim for this study was to evaluate above-ground re-growth of parent plants after cutting in the mine waste materials and soil types mentioned above. The ability of established grasses to re-grow after a cutting event was determined by cutting the above-ground biomass of the parent grasses, after which it was scored according observable above-ground growth in the following growth season. The measurement of re-growth was subjectively done by scoring the grasses according to observable above-ground biomass. Re-growth was observed for all the perennial grass species. This can be ascribed to the grasses showing resilience to stress factors attributed by the growth media; or new grasses which emerged from seed that collected in the pots, being mistaken for re-growth; or new emerging grasses from the nodes of stolons and/or rhizomes being mistaken for re-growth. However, the emergence of new grasses was an indicator of good health, as biomass allocation to rhizomes and stolons is reduced under low nutrient availability and stress conditions. Therefore the emergence of new grasses is indicative that the plant is either tolerant to stress conditions or that the plant adapted to the restriction of growth due to the roots being bound to the size of the pot. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Sustainable rehabilitation can be compromised by the inability of vegetation to survive in hostile mine wastes on a long-term basis. The adverse chemical and physical properties of mine wastes, together with extreme pH conditions and lack of nutrients, provide poor growth conditions for vegetation during seed development and germination. This raises concern for the long-term survival of vegetation through means of seed production when under stress from the punitive properties of mine wastes. Seed vigour is a function of a variety of factors to which the parent plant is subjected during seed formation and maturation. Environmental conditions experienced by the maternal plant during the growth season plays a significant role in determining subsequent germination rates in seeds. Traits of offspring seed depend on the abiotic environment attributed by the growth medium during seed development and maturation The general aim of this study was to determine the viability of seed produced by a previous generation of grass species established in eight different mine wastes and two soils (namely: gypsum wastes; gold tailings with low pyrite content; gold tailings with high pyrite content; platinum tailings; kimberlite mine waste; fluorspar mine waste; andalusite mine waste; coal discard; red soil; and vertic soil) in order to identify suitable species for specific mine wastes to ensure long-term survival through means of seed production. The species selected included: Eragrostis curvula; Eragrostis tef; Cenchrus ciliaris; Eragrostis curvula; Digitaria eriantha; Cynodon dactylon; Chloris gayana; Hyparrhenia hirta; and Sorghum bicolor. The progeny seed‟s viability and ability to germinate were determined through a pot trial study and additional germination testing at the laboratory of Advance Seed (Pty) Ltd. (AS). The germination results were correlated with the growth media analyses by statistical non-parametric correlations which indicated several significant correlations among the growth media properties themselves, and with the germination of the progeny seed. C. gayana (Rhodes grass) seed had poor germination percentages, especially seed harvested from Rhodes grass grown in acidic wastes. Seed harvested from each of the E. curvula grasses grown in various mine wastes, had excellent germination percentages. According to the Repeated Measures ANOVA statistical analysis, there was a significant influence of the growth media in which the parent grass were grown as a variable on the germination of the progeny seed batches from S. bicolor, C. ciliaris, C. gayana, and D. eriantha, indicating that the environmental factors as attributed by the growth media, i.e. the eight different mine waste materials and two soils, and experienced by the maternal plant, did indeed influence the germination of progeny seed. However, it was found that significant correlations between the properties of the growth media and the germination of the progeny seed, was species dependent. The second general aim for this study was to evaluate above-ground re-growth of parent plants after cutting in the mine waste materials and soil types mentioned above. The ability of established grasses to re-grow after a cutting event was determined by cutting the above-ground biomass of the parent grasses, after which it was scored according observable above-ground growth in the following growth season. The measurement of re-growth was subjectively done by scoring the grasses according to observable above-ground biomass. Re-growth was observed for all the perennial grass species. This can be ascribed to the grasses showing resilience to stress factors attributed by the growth media; or new grasses which emerged from seed that collected in the pots, being mistaken for re-growth; or new emerging grasses from the nodes of stolons and/or rhizomes being mistaken for re-growth. However, the emergence of new grasses was an indicator of good health, as biomass allocation to rhizomes and stolons is reduced under low nutrient availability and stress conditions. Therefore the emergence of new grasses is indicative that the plant is either tolerant to stress conditions or that the plant adapted to the restriction of growth due to the roots being bound to the size of the pot. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Master of Science / Department of Agronomy / Ganga M. Hettiarachchi / Mine waste materials from the Tri-State mining region in Kansas, Missouri, and Oklahoma pose environmental hazards. The area is contaminated with trace elements, such as Pb, Zn and Cd, which are transported to surrounding areas through water, wind erosion, and runoff. Phytostabilization or establishing healthy vegetative cover could be used to reduce or control these contaminated materials from further spreading with wind and water. However, further research is needed to monitor the long-term sustainability and assess if high applications of compost amendments could help to facilitate soil reclamation. The overall focus of this thesis was to monitor long-term effects of compost or lime additions at two different rates, with or without other soil amendments, on soil properties, plants, and soil biota. We used the earthworm avoidance test as a screening tool for testing effects of soil amendments on ecotoxicity. In the first field study, pelletized manure compost additions of 448 Mg ha⁻¹ significantly decreased the bioavailable Pb, Zn, and Cd while increasing plant nutrients, vegetative cover, and plant biomass as compared to the contaminated control and the low addition of compost (224 Mg ha⁻¹) over 2.5 years. Plant tissue metal concentrations with compost addition did not show any phytotoxicity in this study. Lime additions did not show any significant effect on any of the measurements. Results from the first study suggest that one time addition of large quantities of compost at 224 to 448 Mg ha⁻¹ can support establishing and maintaining healthy vegetative cover at least for a 2.5 year period. In the second field study, long-term monitoring of the effectiveness of the amendments was studied. Compost was applied at two different rates (45 or 269 Mg ha⁻¹) in 2006. Various chemical properties, microbial activities, and vegetative growth or plant biomass were measured approximately for 4.5 years to evaluate long-term changes in soil quality and sustainability of phytostabilization efforts, when combined or assisted with soil amendments to improve the quality of trace element-contaminated mine waste materials. Plants grown with compost additions of 269 Mg ha⁻¹ showed higher nutrients, biomass, and enzyme activities as compared to plants grown on the contaminated control and with the low addition of compost (45 Mg ha⁻¹) over 4.5 years. Decrease in plant biomass and enzyme activities seen in the high compost treatments by the end of the study period suggested that long-term sustainability of these efforts may require repeated addition of soil amendments every 4 to 5 years. Additionally, a laboratory study was conducted to assess the long-term effects of treatments used in the second field study on ecotoxicity using the avoidance behavior responses of the earthworm Eisenia fetida. There was no mortality of earthworms after a 48 h exposure period of any of these treated and untreated mine waste materials. Avoidance was clear for the contaminated control and the low compost treatment (45 Mg ha⁻¹). Moreover, the contaminated control did show habitat limitation (< 20% of earthworms was found in test soil). Current research studies provide evidence that, high rates of compost applications can be used to stabilize and reduce the bioavailability of trace elements in mine waste materials.

Doctor of Philosophy / Department of Agronomy / Gary M. Pierzynski / The bioavailability of Pb and Zn is linked to the solubility of solid phases and other soil chemical characteristics, which is associated with their environmental risk, suggesting that in situ stabilization of these elements can be accomplished by influencing their chemistry. However, more research is needed to investigate the effectiveness of different soil amendments on reducing Pb and Zn bioavailability. A lab study was conducted to evaluate the effects of five different P amendments and time on Pb/Zn speciation in a contaminated soil using synchrotron-based techniques, while a field investigation studied the effects of composted beef manure on plant biomass production and the influence on microbial function, size, and community shifts. In the lab study, the Pb-phosphate mineral plumbogummite was found as an intermediate phase of pyromorphite formation, which has not been documented until now. Additionally, all fluid and granular P sources were able to induce Pb-phosphate formation, but fluid phosphoric acid (PA) was the most effective with time and distance from the treatment. However, acidity from PA increased the prescence of soluble Zn species, which can have negative environmental consequences. Granular phosphate rock (PR) and triple super phosphate (TSP) reacted to generate both Pb- and Zn-phosphates, with TSP being more effective at greater distances than PR. In the field study, compost additions of 269 Mg ha[superscript]1 significantly decreased bioavailable Zn, while increasing estimated available water, plant nutrients, and plant biomass as compared to a contaminated control and low addition of compost (45 Mg ha[superscript]1) over three years. Additionally, compost additions of 269 Mg ha[superscript]1 significantly increased microbial enzyme activities, nitrification, and microbial biomass over the contaminated control through the duration of the study. Increases in microbial activity and biomass are related to increases in total C, available water, and extractable P, while negative relationships were found with electrical conductivity and with bioavailable Zn. The addition of lime or lime plus bentonite with compost did not further reduce metal availability, increase plant biomass, or improve the size or function of microbial communities. High compost additions caused a slight shift in microbial community structure according to phospholipids fatty acid analysis. Increases in the mole percents of both Gram-positive (Gm[superscript]+) and Gram negative (Gm[superscript]-) bacteria were found depending on site. Microbial biomass of Gm[superscript]+, Gm[superscript]-, and fungi were also increased by high compost additions. Results indicate that large additions of compost are needed to increase microbial biomass, improve microbial activity, and re-establish a healthy vegetative community. This study proposes that organic matter and P amendments can be used to stabilize and reduce the bioavailability of heavy metals in soils and mine waste materials, but must be managed carefully and intelligently.

Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrakech (Maroc), sont directement entreposés sur un substratum schisto-gréseux fracturé. D’une superficie d’environ 16 ha, ils constituent une réelle source de pollution pour l’écosystème local en particulier à cause du Drainage Minier Acide (DMA) vers les eaux de surface et de la nappe phréatique. Les analyses physico-chimiques des eaux souterraines montrent qu’elles sont enrichies par les sulfates, le calcium et le magnésium. Le processus d’évaporation-dissolution est responsable sur les variations des concentrations en éléments majeurs au niveau des eaux souterraines. Le projet de réhabilitation du site minier de Kettara prévoit dans l’un de ses axes de minimiser l’effet DMA par neutralisation à l’aide de dépôts stériles riches en carbonates issus de l’extraction des phosphates de la mine de Youssoufia voisine. Ces derniers seront utilisés à la fois comme amendement des rejets miniers acides et comme couverture évapo-transpirante (barrière capillaire). Les levés géophysiques réalisés ont permis d’imager la structure interne du parc à rejets miniers et d’estimer leur volume (462 400 m3). Les résultats obtenus ont mis en évidence la présence, par endroits, de couloirs fracturés qui constituent des drains privilégiées pour le transfert du DMA vers les eaux souterraines. Le modèle hydrodynamique et de transport de DMA a été élaboré en se basant sur une approche inverse et sur la démarche du modèle équivalent continu (EC). Les résultats des simulations du transport du DMA en cas de réhabilitation du site, ont montré que la pollution diminue d’une façon significative et à long terme. / The Kettara site (Morocco) is an abandoned pyrrhotite ore mine in a semi-arid environment. The site contains more than 3 million tons of mine waste that were deposited on the surface without concern for environmental consequences. Tailings were stockpiled in a pond, in a dyke, and in piles over an area of approximately 16 ha and have generated acid mine drainage (AMD) for more than 29 years. Investigation results show that the hydrochemistry of water samples is characterized by the relatively significant enrichment in Ca2+, Mg2+ and SO 42-. Seasonal variations in major ion concentrations were partly attributed to dissolution/precipitation processes. The rehabilitation scenario being investigated at the Kettara mine involves using fine alkaline phosphate waste (APW) as both an amendment and a ‘store and release’ (SR) covert. To facilitate the success of this rehabilitation project, it was important to determine the nature of the geological substrate of the tailings pond and the internal structure of the mine wastes, and to estimate the volume of tailings by determining the thickness of the tailings layer in the tailings pond. The surveys geophysics realized made it possible to image the internal structure of the park with mining rejections and to estimate their volume (462 400 m3). The results obtained show the presence of fractured zones that constitute privileged drains for the transfer of the DMA to groundwater. The simulations results of the transport of the AMD in the event of rehabilitation of the site, showed that pollution decreases in a significant and long-term way.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / With the advent of ever -increasing energy needs, large-scale surface mining has gained new impetus, and there is much concern about reclaiming the mine spoils to bring about beneficial land uses. This paper presents a decision making algorithm labeled PROTRADE, and a case study of the Black Mesa region in Northern Arizona. PROTRADE considers a set of objective functions, a set of physical constraints, articulates the preferences of the decision maker in a progressive manner, and generates a set of alternative solutions. The decision maker is then able to trade level of achievement, for each objective function, against the probability of achieving that level.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / The suitability of treated municipal sewage effluent for the irrigation of deep- rooting plant material for the rehabilitation of copper mine tailings was studied at the Cyprus Pima Mining Company. The effectiveness of treated sewage effluent was compared with well water on the growth and survival of trees, legumes and grasses. The species studied were eucalyptus (Eucalyptus rostrata), native mesquite (Prosopis juliflora), palo verde (Cercidium floridum), desert tobacco (Nicotiana lauca) barley (Hordeum vulgare), perennial rye grass (Lolium perenne), alfalfa (Medicago sativa), and blue lupine (Lupinus augustifolius). Sprinkler and tree -well irrigation methods were used to apply the treated sewage effluent and well water to steep tailing slopes. The treated municipal sewage effluent was found to be a practical irrigation substitute for well water and a good source of plant nutrients such as nitrogen and phosphorous. Effluent produced better survival and growth than did well water with or without augmentation.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Mathematical simulation of the erosion process is accomplished by using a time series of hydrologic parameters as inputs into a modified form of the Universal Soil Loss Equation. A parameter to account for antecedent moisture conditions was found to improve the predictive success of the Universal Soil Loss Equation. The simulation predicts sediment yield resulting from a stochastic sequence of precipitation events on an experimental watershed. This sediment model will be used as a component in a larger, more complex hydrologic simulation model which can be used to determine optimum reclamation practices for the strip mined areas of the arid Southwest. Data from regraded strip mine spoils at the Black Mesa of Arizona are used in calibrating the model.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Lynx Creek Watershed is located eight miles southeast of Prescott, Arizona, on the Prescott National Forest. The watershed consists of 13,600 acres, which are National Forest Lands. Approximately 600 acres in the watershed are patented mining claims. Gold was discovered in Lynx Creek in 1863 and the watershed was extensively mined for gold, silver and copper. The aftermath of the mining has resulted in numerous mine shafts, waste dumps and mill tailing ponds that were abandoned after the ore was played out. Drainage from the orphaned mine sites contribute a certain extent of toxic mineral and sediment pollution into Lynx Creek and eventually into Lynx Lake. Lynx Creek carries runoff which is slightly acidic in nature and has high concentrations of copper, manganese, iron, zinc and sulfates. The mineral pollutants have reduced the recreational and fisheries potential of the Lake. The Sheldon Mine complex consisting of a waste dump and the mill tailing dump were considered the major sources of pollutants into the Lake. The Sheldon Tailings pond was rehabilitated during the summer of 1975 and the waste dump during the summer of 1976 as part of a reclamation study that is being sponsored by SEAM (Surface Environment and Mining). The study is being conducted cooperatively by the School of Renewable Natural Resources, University of Arizona, and the Prescott National Forest. Both sites were culturally treated and dressed with lime and topsoil. Studies are currently being conducted to measure the beneficial effects of the reclamation projects.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Intensive strip and leach mining activity within a confined region usually causes environmental impacts both on the land and on water quality. Adverse water quality effects could be realized long after any mining activity has ceased due to the continuous leaching by precipitation of contaminants from spoils piles and leach dumps. The Miami, Arizona region is unique in its surface and subsurface hydrology. Two unconnected aquifers underlay the region with both serving as domestic (private and municipal) and industrial (mining) supply sources. The shallow floodplain alluvial aquifer is hydraulically connected to surface drainage from mine tailings and leach dumps. Several wells drawing from this aquifer have been abandoned as a municipal supply source due to severe water quality degradation. Water quality in these wells varies directly with precipitation indicating a correlation between surface drainage over and through tailings and leach piles. Expansion of spoils dumps into natural recharge pathways of the deeper Gila Conglomerate aquifer has raised concern that this aquifer may also be subjected to a long term influx of mine pollutants. Questions have also been raised concerning the potential effects of a proposed in situ leaching operation on the water quality of the conglomerate aquifer.