• Tunnel and Underground Space
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• v.22 no.6
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• pp.373-382
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• 2012

Cessation of dewatering usually results in groundwater rebound after closing an underground coal mine because the mine voids and surrounding strata flood up to the levels of decant points such as shafts and drifts. Several numerical models have been developed to predict the timing, magnitude and location of discharges resulting from groundwater rebound. This study reviews the numerical models such as VSS-NET, GRAM and MODFLOW, and compares their scopes of assessment at different spatial and time scales. In particular, the GRAM model was reviewed in details to implement it. This paper describes the implementation of GRAM model and its application to the Dongwon coal mine in Korea. The application showed that the groundwater level modeled at the shaft of Dongwon coal mine using the GRAM model is similar to the observed one in the field.

• Journal of Soil and Groundwater Environment
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• v.19 no.1
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• pp.34-45
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• 2014

A variety of physical, chemical, and microbiological techniques have been developed to deal with soil and groundwater contamination. However, in the presence of the large portion of soil micro-environments, contaminant rebound and/or tailing have been frequently reported. Case study of total petroleum hydrocarbons (TPH) removal by full-scale land farming showed that contaminant rebound and/or tailing occurred in 9 out of total 21 cases and subsequently resulted in problems of a long term operation to satisfy TPH guidelines of contaminated soil and groundwater. The main cause of contaminant rebound and tailing is considered to be the strong interactions between contaminants and micro-environments including micro-particles, micro-pores, and organic matter. Thus, this study reviewed the effects of soil micro-environments of soil and groundwater on the removal efficiency for both heavy metals and petroleum contaminants. In addition, the various methods of sampling, analysis, and assessment of soil micro-environments were evaluated. Thorough understanding of the effects of soil micro-environments on contaminant removal will be essential to achieve a cost-effective and efficient solution to contaminated sites.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.515-518
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• 2003

Groundwater recharge rate can be estimated from groundwater head rebound due to rainfall. Groundwater level changes are monitored for 10 months at Yugu area. Difference between two recharge rates calculated by rainfall and by effective rainfall is 1.1%~1.6%. Since this method ignores soil water percolation during groundwater level regression, the actual recharge rate may be higher than estimated one by cumulative rainfall and groundwater level change.

• Journal of Soil and Groundwater Environment
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• v.29 no.5
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• pp.14-26
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• 2024

This study investigated the effectiveness of calcium polysulfide (CPS; CaS_x) injection for the in-situ immobilization of cadmium and zinc-contaminated groundwater. The research focused on the impact of CPS injection on groundwater quality parameters, such as dissolved oxygen (DO), oxidation-reduction potential (ORP), and pH, as well as heavy metal precipitate formation and aquifer's microbial community dynamics on a field scale. The results demonstrated that the injected CPS formed a reactive zone, effectively reducing cadmium and zinc concentrations for a limited period. However, contaminant rebound occurred over time, necessitating repeated CPS injections. A single injection of CPS achieved a removal efficiency of 70~99%, lasting approximately 20 days. In contrast, repeated injections sustained the removal effects up to 37 days. Chemical analyses confirmed the precipitation of cadmium and zinc sulfide (CdS and ZnS), which remained stable in the aquifer even 86 days post-injection. Elemental sulfur (S) was detected in a significant quantity, contributing to the observed low DO levels. Microbial community exhibited a shift from an initial prevalence of sulfur-oxidizing and iron-oxidizing bacteria to a later dominance of sulfate-reducing bacteria following the cessation of high DO recycled water inflow, potentially enhancing the formation of CdS and ZnS.