Groundwater Flow Model of Oil Shale Mining Area

Abstract

During the next decade changes are expected in the western area of the active part of the Estonia oil shale deposit since Ojamaa mine started to dewater the oil shale layer and environmental impact assessment is in the process of estimating the influence of dewatering on the site of Uus-Kiviõli mine. Aidu open cast is planned to close down in 2013 as the resources of oil shale indicated in the mine permission are ending. Closing of Viru mine in 2015 has been discussed. As the oil shale resources at Aidu and Viru area end, the mine sites will be closed and flooded. Therefore the groundwater table will increase in closed sites and will decrease in prospective areas. To estimate and visualise the situation, computational modeling of groundwater flow has been applied in most cases to estimate the future situation. The current analysis describes the process of groundwater modelling as well as offers possibilities of estimating the accuracy of the model and of the model calibration process. Water inflow rate into Estonia mine has been analysed.

Impact of Oil Shale Mining on Flow Regimes in Northeast Estonia

“…This paper assesses the impact of changes in drainage associated with Estonian oil shale mining on hydrological pathways and flow regimes in small-and medium-sized lowland catchments. A variety of groundwater models have been used (Lind 2010;Reinsalu et al 2006) to assess the impacts of oil shale mining on hydrogeology. The study assessed: (1) changes in catchment area and runoff characteristics over time as a result of mining operations, (2) the vulnerability of small rivers to hydrological regime change in mining areas, and (3) modes and extent of change in contributing drainage areas as a result of mining within different sub-catchments of the River Purtse.…”

Impact of the shale mine on the River Purtse hydrological regime in north-east Estonia

“…This effect stretches up to 35 m in depth and 2.51cm outside of the mining area (Kattai et al 2000), creating groundwater infiltration to the mines. Recently, a variety of models have been used in groundwater studies (Reinsalu et al 2006;Lind 2010) to assess the impact of oil shale mining on hydrogeology. Modeled data from these models have also been used in the current research.…”

Analysis of long term hydrological records to assess the changing regime and pathways in oil shale mining districts of North East Estonia

“…As a result an extensive cone of depression [18] stretching up to 35 m in depth and 2.5 km outside of the mining area [19] creates groundwater flow gradients towards the mines. After closure of mines in the last two decades, new massive underground water bodies have developed in the mine voids [12,13].…”

“…[9][10][11]). Recently, a variety of models have been used in groundwater studies [12,13] to assess the impacts of oil shale mining on hydrogeology which inform this current research. Previous analyses [14,15] have briefly demonstrated the impact of mining on hydrological regime and run-off in small to medium Estonian river systems (taken here to be a size range of 100 -1000 km 2 ).…”