Reclamation Design Research Articles

Assessing vegetation recovery in reclaimed opencast mines of the Teruel coalfield (Spain) using Landsat time series and boosted regression trees

Opencast mining is an activity that caters to many economic sectors; however, it has a large impact on society and the environment. After mining, the major concern is to restore the previous land cover, which was generally a natural vegetation cover. Establishing permanent vegetation cover can restore landscape connectivity and previous ecosystem functions, enhance aesthetic values and prevent off-side effects associated with post-mining landscapes. Opencast mining reclamation deals with these issues with several strategies that aim to develop a vegetation cover after mining activity has stopped. However, not all reclamation actions are effective, and assessing their efficiency by monitoring vegetation development at reclaimed sites is a time-consuming task because it usually involves extensive field work. In this study, we present a semi-automatic approach based on analysing satellite data (Landsat) time series and using a machine learning technique to identify suitable conditions for vegetation development at reclaimed opencast mines. We analysed the Teruel coalfield (Aragón, central-eastern Spain). This area is a representative Mediterranean-Continental region that is of particular interest due the diversity of reclamation actions that have been applied and the increase in drier conditions during the last decades. Conditions were described with topography derived variables, technical reclamation features and drought-occurrence variables as potential explanatory factors. The implemented approach allowed us to identify the main abiotic filters for vegetation of this geographic region: the water availability and soil retention (both controlled by the topographic slope), and the proximity to seed sources. The analysis evidenced the negative influence of drought occurrence on vegetation development, and different responses were found depending on the timescale at which drought is calculated. Our results indicate that the reclamation landform model is the main key factor influencing vegetation development. A model such as the smooth berm-slope increases water availability and controls soil erosion, and hence, improves vegetation development. In addition, we found that further than 500-600 m from the mine, the effect of seed source declines dramatically. Therefore, all these issues should be considered in future reclamation designs in a Mediterranean-Continental environment. Our methodology could be adapted to other geographic regions where spatial environmental data are available.

Comparative Evaluation of Polyflake as Material for Repair and Reclamation Design

This paper empirically quantified polyflake deposition repair compared to alternative thermal spray techniques specifically when applied to 1045 steel shaft. Polyflake is a composite of c-glass flakes and high-performance modified resin that can substantially protect ferrous and non-ferrous surfaces. In the repair and reclamation of defective or damaged metal structures by deposition of engineering materials, thermal spray techniques using metals or ceramics are commonly favored over their counterparts due to their versatility of the type of deposition material utilized. However, a simpler and more economical approach is polyflake material deposition. In this study, a full factorial design of experiment is used to characterize the main effects of three materials and techniques used for deposition: c-glass high temperature resin polyflake, 303 stainless steel metallization, and aluminum oxide ceramic deposition repair. The experiments were used to evaluate the mechanical properties and performance of the repaired 1045 steel shafts. In addition, environmental impact assessment was conducted to evaluate the environmental performance of the three repair techniques implemented. The experimental results show that repair material and technique have significant effect on the hardness of the repaired components and their abrasion resistance properties. Upon completion of 75 hours of simulated service operation of the repaired shafts, aluminum oxide ceramic coating repair showed dominance in overall quality characteristics; however, it had highest cost demands and higher energy footprint.

Case study on long-term ground settlement of reclamation project on clay deposits in Nansha of China

In the design of reclamation, long-term settlement is seriously concerned. This paper presents a case study on the ground settlement of a reclamation project in Nansha, China. Fourteen undisturbed soil samples were taken at different depths from this site. Both oedometer tests on fourteen specimens and triaxial hydraulic conductivity tests on nine specimens were conducted. Finite element (FE) modelings using soft soil creep (SSC) model or soft soil (SS) model for modeling clayey soils with or without creep and the calculation using a new simplified method were performed to analyze the consolidation settlement of clay deposits subjected to filled loadings. The FE simulated results and calculated results from the new simplified method were compared with the monitored data in the field. Results show that the curves of the FE modeling using SSC model and the calculation from new simplified method have the same trends as those of the measured settlements. The creep contributes to excess pore pressure dissipation during the consolidation. Furthermore, ground settlements of the reclamation are predicted with the aid of the FE and new simplified method analysis. These predictions can provide the essential information for engineers to control or reduce the settlement in future.

Opportunistic wetland formation on reconstructed landforms in a sub-humid climate: influence of site and landscape-scale factors

Initiation of wetland features is integral to sustaining landscape eco-hydrological function and meeting defined goals in surface mine reclamation. Within the sub humid climate of the Athabasca Oil Sands, Canada, the water generation mechanisms (external water sources, internal feedback mechanisms) that enable wetlands to form opportunistically on recently reconstructed landscapes are currently unknown, restricting the flexibility in mine closure planning. To address this knowledge gap, we interpret site and local physical characteristics of opportunistic wetlands within the Athabasca Oil Sands through a synoptic survey. Wetlands formed in ~ 8% of the random survey transect areas designed and planted for forestlands. Wetlands had vegetation structures characteristic of woody Salix spp. swamps and narrow-leaved Carex spp. marsh wetland types, with minor coverage of open water marshes. Wetlands formed opportunistically over a range of slopes, aspects and topographic positions, across contrasting fine and coarse-textured landforms. However, different wetland establishment and maintenance controls exist on fine and coarse-textured landforms. On coarse-textured landforms with large groundwater transmissivity, wetland formation was influenced by landscape-scale factors; wetlands were restricted to the toes of slopes and areas intersecting groundwater. On fine-textured constructed landforms, small and large wetlands occurred on lower landscape elevations with the potential for the external (cumulative) water sources, and in hydrologically isolated locations with little potential for runoff contribution from adjacent forestlands (saturation and wetland formation through internal feedback mechanisms). Regardless of landscape position, wetlands formed on flat areas and in shallow inward draining endorheic pans with clay rich soils where low water storage potential promotes frequent surface saturation. These findings have important implications in landscape reclamation design, suggesting that passive techniques that support internal feedback mechanisms may offer a more cost effective reclamation approach compared to more active, expensive techniques that aim to develop wetlands with external water sources.

Quantifying Topographic Characteristics of Wetlandscapes

Topography underpins natural processes ranging from incident solar radiation to overland flow and water pooling. Despite the influence of topography on natural processes, especially in wetland ecosystems reliant on uplands for water inputs, topography has not been adequately incorporated into reclamation planning. Instead, wetland reclamation projects are typically guided by height-to-length ratios that produce little resemblance to natural wetlands. We present a methodology to quantify the topographic characteristics in landscapes with an abundance of wetlands to guide the reclamation of naturally appearing and self-sustaining wetlandscapes. Topographic characteristics in over 3000 sample landscapes were quantified using terrain roughness and landform element composition and configuration. A large set of metrics was reduced to a statistically independent subset that was applied and compared across three natural regions and a gradient of disturbance. Our results showed that surface roughness and landform element patterns significantly differ among natural regions and that high disturbance landscapes significantly differ from other disturbance levels. To ensure reclaimed wetlandscapes are naturally appearing and self-sustaining, they should replicate the topographic characteristics found within the distribution of surrounding natural landscapes by applying topographic characteristic benchmarks to reclamation design. The presented methodology can be used as a step towards achieving this goal.

Aplicação da metodologia de projeto de experimentos na dosagem de misturas de reciclagem de pavimentos com adição de cimento

Nesse estudo foi verificada a aplicação da metodologia de projeto de experimentos na dosagem de misturas de reciclagem de pavimentos com adição de cimento. Adotou-se um método de dosagem que avalia propriedades mecânicas, volumétricas e de erodibilidade, e foram desenvolvidas todas as etapas que contemplam um projeto de experimentos. O planejamento possibilitou definir as variáveis que exercem maior influência nos resultados, de modo a estabelecer uma matriz experimental abrangente e reduzida. Na análise dos resultados foi possível quantificar o efeito dos fatores controláveis estudados (teor de cimento e porcentagem de fresado) em cada variável de resposta. A partir da otimização multivariada, obteve-se o ajuste ótimo dos fatores controláveis considerando todas as variáveis de resposta simultaneamente. A ferramenta adotada nesse trabalho se mostrou bastante eficiente, podendo ser amplamente empregada na otimização de processos, como é o caso da dosagem de misturas recicladas.

Evaluating sediment production from native and fluvial geomorphic-reclamation watersheds at La Plata Mine

San Juan Coal Company reclaimed 743 ha at its La Plata Mine using the GeoFluv™ fluvial geomorphic reclamation design method from 1999 through 2008 to achieve long-term stability against erosion (no major slope blowouts and rill and gully formation), reduced maintenance, and increased biodiversity as compared to traditional reclamation methods (e.g. terrace, berm, and downdrain designs). Qualitative inspections of the completed reclamation confirmed the fluvial geomorphic reclamation method benefits. In the fall of 2011, the company began implementing a research study to quantify the sediment production rate from these geomorphic landforms and surrounding undisturbed native lands.Data were acquired from subwatersheds differentiated as native (undisturbed by mining), fluvial geomorphic design with topdressing and poorly established vegetation, and fluvial geomorphic design with topdressing and significant vegetation establishment. The three subwatersheds were selected to ensure similar size, aspect, and slope and were located close together to minimize storm variation effects. Temporary check-dam-type sediment control structures designed to impound runoff from a 2-yr, 1-h storm were installed at each subwatershed outlet. Erosion pins in the impounded area facilitated sediment deposition measurement. Precipitation was recorded by the La Plata Mine Meteorological Station and supplemental site-specific precipitation gauges.Precipitation sufficient to cause sediment transport provided data for the end of the 2012, all of the 2013, and the beginning of the 2014 water years. The site data provided direct relationships between sediment production and precipitation. The sediment yield from the undisturbed native site was 9.53 t ha−1 yr−1, while the fluvial geomorphic design with topdressing and poorly established vegetation site averaged 13% lower than the native site, and the fluvial geomorphic design with topdressing and significant vegetation establishment averaging 41% lower sediment yield than the native site. Land-disturbing activities that can accelerate erosion and sediment yield will accompany global population growth. The results of this study indicate that use of this land reclamation method can mitigate erosion and sediment yield increases associated with that growth.

The distribution and migration of sodium from a reclaimed upland to a constructed fen peatland in a post-mined oil sands landscape

Post-mine landscape reclamation of the Athabasca Oil Sands Region requires the use of tailings sand, an abundant mine-waste material that often contains large amounts of sodium (Na+). Due to the mobility of Na+ in groundwater and its effects on vegetation, water quality is a concern when incorporating mine waste materials, especially when attempting to construct groundwater-fed peatlands. This research is the first published account of Na+ redistribution in groundwater from a constructed tailings sand upland to an adjacent constructed fen peat deposit (Nikanotee Fen). A permeable petroleum coke layer underlying the fen, extending partway into the upland, was important in directing flow and Na+ beneath the peat, as designed. Initially, Na+ concentration was highest in the tailings sand (average of 232mgL−1) and lowest in fen peat (96mgL−1). Precipitation-driven recharge to the upland controlled the mass flux of Na from upland to fen, which ranged from 2 to 13tons Na+ per year. The mass flux was highest in the driest summer, in part from dry-period flowpaths that direct groundwater with higher concentrations of Na+ into the coke layer, and in part because of the high evapotranspiration loss from the fen in dry periods, which induces upward water flow. With the estimated flux rates of 336mmyr−1, the Na+ arrival time to the fen surface was estimated to be between 4 and 11years. Over the four-year study, average Na+ concentrations within the fen rooting zone increased from 87 to 200mgL−1, and in the tailings sand decreased to 196mgL−1. The planting of more salt-tolerant vegetation in the fen is recommended, given the potential for Na+ accumulation. This study shows reclamation designs can use layered flow system to control the rate, pattern, and timing of solute interactions with surface soil systems.

Analytical Approach to Estimate Salt Release from Tailings Sand Hummocks in Oil Sands Mine Closure

Integrated surface water and groundwater models are well suited for evaluating the long-term performance of oil sands mine closure landscapes to optimize reclamation designs that satisfy performance criteria. However, the scale of the problem makes it difficult to evaluate a large number of design alternatives using numerical models, while at the same time satisfying numerical criteria, such as the courant and peclet numbers. The problem becomes particularly challenging in the design of permeable sand tailings hummocks overlying relatively impermeable composite tailings, where vertical advective flushing of process-affected water through the tailings hummocks is coupled to lateral transport of diffusive release from the underlying composite tailings. We developed an analytical solution that rapidly estimates long-term mass loadings from the sand tailings without the challenges typically associated with numerical modelling. Advection and dispersion in the flushing zones, progressive diffusion into underlying low permeability layers, and purely diffusive release are all considered. A comparison of the analytical solutions to numerical simulations for a series of simple hypothetical cases demonstrated that the analytical solutions provide a reasonable simulation of the mass loadings from the reclaimed landscapes over the design life. Although the approach needs to be further verified and validated for more realistic complex mine reclamation conditions, the analytical framework provides a foundation for hydrologic analysis in mine reclamation and closure in the northern boreal environment.

Comparing layer types for the use of PavementME for asphalt emulsion Full Depth Reclamation design

While Full Depth Reclamation (FDR) has many potential cost and environmental benefits, it is necessary to ensure that the pavement with recycled materials will perform adequately. One way this can be accomplished is understanding how to best complete the structural design of FDR pavements. Because FDR is a composite material, it does not fit neatly into any of the existing material characterization models considered by the AASHTOWare Pavement ME design (PavementME) software. Until a new layer type is developed that considers the unique properties of these recycled, stabilized base courses, it is essential to understand how to use existing structural design tools to model FDR in a way that accurately captures its structural benefits. In this research, three different FDR mixtures were tested to obtain all necessary material properties required as inputs for PavementMe to consider this material as both asphalt concrete (AC) and unbound granular material (UGM). Using traffic information from the two Arkansas highways climate data, two different MEPDG models were created for each mixture, one characterizing the FDR layer as AC and the other as UGM. A stronger correlation was found to exist between temperature and modulus, rather than stress state and modulus. All distress predictions by PavementME were higher for the FDR as UGM except AC rutting for one mixture and bottom-up fatigue cracking. Overall, considering FDR as AC seemed to more accurately account for the structural benefits of FDR.

Slope stability and landform design in a coarse coal refuse reclamation.

Restoration of abandoned mine lands is on-going in Appalachia and across the United States. One potential technique to reclaim these areas is through the use of geomorphic landforming combined with paper mill residuals used as a soil amendment. The geomorphic approach attempts to approximate the long-term, steady state landform condition, leading to reduced erosional adjustment as compared to standard engineered fill designs. This study analyzed regraded mine refuse slopes for safety and erosion sustainability under a 100-year storm event for the Royal Scot refuse pile located near Anjean, WV. The project involved the design and evaluation of a cap and cover system composed of two layers. The first layer is a 60 cm. compacted barrier layer (hydraulic barrier) and second is a 30cm vegetative growth layer. The focus of the analysis was the effectiveness of the hydraulic barrier layer and the final slope stability of the system. A reclamation design was prepared and 3D finite element modeling was performed to assess ground surface terrain profiles considering weather and material strength. Results from the modeling indicate that for a 100-year storm event, the slope remains stable with a factor of safety ranging from 1.3 to 1.9 for different slope profiles. After the 100-year storm event, the hydraulic barrier reached a 20% degree of saturation proving its effectiveness with minimizing infiltration into the reclamation fill.

A column study of the hydro-mechanical behavior of mature fine tailings under atmospheric drying

In this paper, the hydro-mechanical behavior and physical properties of mature fine tailings (MFT) under atmospheric drying are investigated through a column study. In the study, evaporation takes place in the development of suction in the upper parts of the column and increasing suction leads to higher strength in the tailings. After 5days, the suction in the first lift is around 17kPa in the upper part of the column. When a second lift is added, the first lift initially loses strength but over a 30days’ period, the strength is recovered to its prior value and suction in the second lift reaches 500kPa. The vane shear strength values show a substantial increase in the strength of the MFT after 30days under atmospheric drying and drainage. The 90% strength found in the column exceeds the threshold (5kPa). The hydraulic-mechanical properties of the deposited tailings are closely coupled due to several mechanisms, such as evaporation, drainage, self-consolidation, suction and crack development. The findings of this study will provide a better understanding of the placement behavior of multiple lifts of MFT and thus contribute to reclamation design standards and reduce the use of dedicated disposal areas.

Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment

The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

Responses of the wetland grass, Beckmannia syzigachne, to salinity and soil wetness: Consequences for wetland reclamation in the oil sands area of Alberta, Canada

Reclamation of the boreal landscape, including both wetlands and uplands integrated into complex watersheds, has presented a challenge over the past decade with few attempts. Relevant today is wetland/peatland reclamation on reclaimed landscapes positioned on saline sand deposits left on ‘in-pits’ from open pit oil sands mining. Part of the reclamation challenge lies in choosing characteristic species that are tolerant of conditions present on the reclaimed landscape. Species need to both survive harsh environmental conditions and facilitate succession from mineral-based wetlands (marshes) to peat-based ones (fens). A two-by-six factorial experiment was implemented in a greenhouse under two moisture levels: saturation to 2.5cm below the soil level (high) and saturation to 7.5cm below the soil level (low) and six salinity treatments: 5mgL−1 Na+, 400mgL−1 Na+, 850mgL−1 Na+, 1250mgL−1 Na+, 1850mgL−1 Na+, and 2700mgL−1 Na+. Water level affected total biomass, with the low water level producing higher biomass. Sodium concentration affected biomass, root:shoot ratio, stomatal conductance, evapotranspiration, and photosynthetic rate; all responses were similar for the lower Na concentrations and declined after the 850mgL−1 treatment. We conclude that B. syzigachne tolerates Na levels of 850mgL−1 and survives with diminished performance at treatment of 850mgL−1 up to 2700mgL−1. With these salinity responses, along with broad tolerance to water levels, B. syzigachne has great potential as an early colonizing annual species for conditions predicted to occur in many of the in-pit reclamation designs.

Geotechnical Investigations at the Dalian Offshore Airport, China

Based on the geotechnical investigation data of artificial island at Dalian Offshore Airport, the spatial distribution of the physical and mechanical properties of deposit soils was statistically analyzed. The field investigation revealed that the deposit soils could be subdivided into three strata, i.e., the top marine deposit stratum, middle marine-continental deposit stratum, and deep continental deposit stratum. Field and laboratory test results demonstrated that the marine deposit soils had high water content (31.2% < wn < 63.10%), large void ratio (0.88 < e0 < 1.75), low permeability (kv < 10−6 cm/s), flow-plastic state (IL > 1), under consolidated (OCR < 1), high compressibility (Es < 4 MPa), low shear strength (11.7 kPa < cu < 43.7 kPa), and low bearing capacity (0 < fak < 120 kPa), they could not be used as natural foundation. The marine-continental and continental deposits were normally consolidated to over-consolidated (OCR ≥ 1), medium compressibility (4 MPa < Es < 20 MPa), high shear strength (29.7 kPa < cu < 73.7 kPa), and high bearing capacity (fak > 120 kPa). In addition, regression analysis results showed that the compression ratio was positively correlated with the natural water content, the coefficient of vertical consolidation was negatively correlated with the plasticity index, and the coefficient of vertical permeability was positively correlated with the initial void ratio. The results of the field and laboratory tests were synthesized to provide a basis for reclamation design.

The impact of reclamation cover depth on the performance of reclaimed shale overburden at an oil sands mine in Northern Alberta, Canada

AbstractMultilayer covers are widely accepted reclamation designs in the oil sands region of northern Alberta, Canada, with an ultimate goal of revegetating to species characteristic of predisturbance native plant communities. To determine the optimal depth of reclamation material required to reclaim overburden shale from an oil sands mine, an evaluation was made of the long‐term performance of six reclamation soil cover depths all placed over overburden. The measured soil water contents from different cover thicknesses at South Bison Hills located at the Syncrude Mine site north of Fort McMurray, Alberta, were used to calibrate and validate a dual‐porosity model in HYDRUS‐1D. The calibrated and validated model was then used to evaluate the influence of cover thickness and climatic variability on plant available water for forest growth. The frequency distributions of actual transpiration (Tr) for six cover treatments with a range of leaf area index (LAI) cases were developed. These Tr frequency distributions were then modified by coupling Tr and LAI. The modified frequency distributions for annual Tr for the six simulated cover thickness highlight the strong nonlinearity between the distributions of Tr over a long‐term (60 years) climate cycle in that incremental increases in cover thickness do not produce proportional increases in Tr. The results indicated that, once the cover thickness exceeds 100 cm, there is little incremental increase in the median value of Tr over the 60‐year climate cycle. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Effects of Sea Level Rise on Coastal Reclamation Projects in Jiaojiang Estuary, China

Sun, Z.; Nie, H.; Huang, S.; Huang, S.; Huang, W.; Zhu, L., and Gao, Y., 2014. Effects of sea level rise on coastal reclamation projects in Jiaojiang estuary, China.In this paper, a series of numerical simulations are carried out to investigate the storm tide characteristics in Jiaojiang estuary and nearshore areas after the proposed cluster reclamation project (from 2011 to 2023) and in different amplitude of sea level rise (SLR) during TC9711 (tropical cyclone Winnie). Special attention is paid on the variations of tidal levels at different locations. Due to reclamation project, It can be found that the maximum tidal levels significantly increase along Niutou Necking-Shanjiaopu section, both banks inside estuary entrance, northern Toumen Harbor and in harbor basin. On the contrary, tidal levels along northern Toumen Harbor, Puba Harbor and southern bank outside entrance decrease clearly. Meanwhile, study on influence of SLR at Haimen Station indicates that impacts of SLR on tidal levels increase as SLR increment grows, appear as periodic variation with the same cycle of tide and bring about maximum variation of tidal levels of 0.382 m and −0.339 m for SLR at 0.6 m. Moreover, investigation of influence of SLR on maximum tidal levels reveals that the maximum tidal levels in domain generally decrease as SLR increases, but those will increase significantly for SLR of 0.03 m and 0.15 m along Sanjiangkou and Niutou Necking. The results are helpful to provide constructive references for disaster prevention and reduction in process of design, construction and completion of reclamation.

BIM 기반의 준설매립전용 Library Browser 개발

본 연구에서는 준설매립분야의 설계자동화를 위하여 준설토 투기장 설계 시 고려되는 상부 및 하부 구조물을 대상으로 Library를 구축하고, 이를 통합 관리할 수 있는 브라우저를 개발하였다. 개발 Library는 주요 단면제원을 변수화하여 형상의 가변성 확보가 가능한 파라메트릭 모델링 방법을 이용하여 작성하였으며, 작업환경에 맞게 표준횡단 및 패밀리 Library로 구분하여 작성하였다. 작성된 Library를 특성별로 구분하여 객체를 관리하고 BIM 기반 모델링 작업 시 객체의 적용이 간편하도록 C# 언어를 이용하여 브라우저를 개발하였다. 개발된 브라우저를 BIM 기반의 3차원 캐드 프로그램에 연동함으로써 간편하게 3차원 모델링, 도면작성 및 물량산출이 가능하고 신규 Library의 작성 및 관리 또한 가능하다. This study has been conducted to building a library intended for structures considered in the design of reclamation for design automation and developing browser for integrated management system. The library has been developed using a parametric modeling method capable of changing section shape, also classifying standard crossing and family library, has been developed according to the working environment. Classified library by the characteristics manages objects and working modeling on based BIM has been developed browser using the C# program for objects to use conveniently. By interworking between developed Browser and 3D Autocad based BIM, it is possible to use easily at design drafting, calculating quantities, developing a new library, and managing a library. The browser using effectively exclusive library to reclamation is developed in this study.

Mine land reclamation and eco-reconstruction in Shanxi province I: mine land reclamation model.

Coal resource is the main primary energy in our country, while Shanxi Province is the most important province in resource. Therefore Shanxi is an energy base for our country and has a great significance in energy strategy. However because of the heavy development of the coal resource, the ecological environment is worsening and the farmland is reducing continuously in Shanxi Province. How to resolve the contradiction between coal resource exploitation and environmental protection has become the imperative. Thus the concept of “green mining industry” is arousing more and more attention. In this assay, we will talk about the basic mode of land reclamation in mine area, the engineering study of mine land reclamation, the comprehensive model study of mine land reclamation, and the design and model of ecological agricultural reclamation in mining subsidence.

Feasibility of In-Situ Aeration of Old Dumping Ground for Land Reclamation

Dumping grounds are characterized by the absence of engineering controls such as base liners and cover layer. Consequently, these dumping grounds present risks for surrounding resources such as soil, groundwater and air. The concern for groundwater contamination by leachate from tropical dumping grounds is heightened due to the greater amounts of rainfall and subsequent infiltration and percolation through the waste mass. The emergent demand for old dumping grounds reclamation drives the need to employ remediation technologies. Generally, in-situ aeration is a remediation method that promotes aerobic conditions in the later stage of dumping ground. It accelerates carbon transfer, reduces remaining organic load, and generally shortens the post closure period. However, high rainfall in tropical areas straitens this technique. For example, pollutants could be easily flushed out and more energy should be required to overcome hydrostatic pressure. Although heavy rainfall could supply sufficient water to the substrate and accelerate degradation of organic matter, it may inhibit aerobic activities due to limited air transfer. The waste characterization from Lorong Halus Dumping Ground (closed dumping ground in Singapore) showed that the waste materials were stabilized after 22 years closure. According to the Waste Acceptance Criteria set by European Communities Council, the waste materials could be classified as inert wastes. One interesting finding was that leachate layer detected was about of 5 - 8 meter depth, which entirely soaked the waste materials. Hence, the reclamation design and operation should be carefully adjusted according to these characters. Lorong Halus Dumping Ground case study can provide a guideline for other tropical closed landfills or dumping grounds.