In the coal phase-out era, achieving sustainable mine closure is significant and prioritizes targets for the mining industry. In this study, the already closed lignite mine of Kardia, North Greece, is investigated, where the mine void left is naturally filled with water. The viability of different repurposing land uses is evaluated, and the natural water level development inside the mine pit is investigated concerning its future uses. The potential for solar photovoltaic (PV) panels developed on mining land and its surrounding area is evaluated in combination with the application of pumped hydro storage (PHS) technology, utilizing pit lake water. Except for electricity system planning, other end-uses that offer multiple, mutually reinforcing and lasting benefits are investigated, such as recreation parks, terrestrial wildlife, aquaculture and agriculture. All repurposing scenarios are evaluated with regard to the spatiotemporal evolution of the lake, by generating forecasts of the dependent variables (rainfall and temperature) via linear (autoregressive integrated moving average) and non-linear (artificial neural network) models. The prediction of pit lake natural development redefines the new land use layout and the land repurposing decisions. This is essential for strategic planning, considering the Greek lignite mining industry’s priority regarding transitioning from the current coal-based electricity to renewable energy sources (RES) technology.

Hydrogeological conditions constitute a crucial factor during mining excavations. However, they could also define when and how rapidly the final pit voids will be filled with water after mine closure. They also influence the final steady-state water volume of the lake formed. This paper investigates the hydrogeological conditions of the Kyparissia surface mine in the Megalopolis lignite field. Due to the very rapid filling from three karstic aquifers, these were the determining factors for ceasing exploitation in 2012. A pit lake has been formed in the mine void since 2017, with an average depth of 30 m and a maximum depth of approximately 36 m, extending to a surface of 0.8 km². The significant role of the hydrogeological setting is highlighted in the creation, maintenance, and development of pit lakes.

Future investment feasibility studies concerning post-mining repurposing utilities and economic transitions should focus on regional water resource management and the hydraulic protection of any utilities. Satellite images in different bands and Digital Elevation Models (DEM) of the Ptolemais basin were processed, leading to a more accurate estimation of the runoff ratio and percolation ratio. Furthermore, the saturated and unsaturated areas were delineated, leading to the recognition of potential artificial ground water recharge zones and zones where appropriate hydraulic protection measures are necessary.