Project intermediate results
WP1 - Climate review and projections
Tasks within this work-package have been aimed at reviewing and recording previous extreme weather events in the mining industry and reviewing historic climate trends in mining regions around Europe and calculating projections of future climate changes for European mining regions for different emission scenarios.
All planned works were finished. Works within this work-package are treated as basic for further works. Short summary of main results from specific tasks are described below:
- Task 1.1 - Identification and analysis of climatic conditions affecting the mining industry
Significant climate-related events, mainly in Europe were identified and documented, with the focus on project partners countries (Greece, Czechia, Poland, Germany, Spain and United Kingdom) that impacted mining activity and contributed lessons from each country represented in the project. The principal cause for mining-affecting incidents was extreme precipitation – specifically extreme rainfall or snowfall. Furthermore, a database of these events has been created and will be maintained throughout the Project.
Summary of deliverable D1.1. Report on analysis of most important climatic conditions including past extreme weather events affecting the mining industry is available here
- Task 1.2 - Establishment of baseline climatic conditions in European mining regions
A climate baseline was created to describe the regions’ current climate conditions that can serve as a reference baseline to assess climate changes. Partners have collected at minimum temperature and precipitation data from their countries and other crucial factors for local regions.
Short summary of deliverable D1.2 Baseline climate report for regions is available here
- Task 1.3 - Development of climate projections for regions
A combination of Global Climate Models (GCMs) and downscaled Regional Climate Models (RCMs) were used by project partners to present data in the form of maps and time plots. The CORDEX (Coordinated Regional climate Downscaling Experiment) project used for the majority of the projections developed in this Task, downscaled GCMs using both statistical techniques and dynamical techniques from several different RCMs. A time of emergence i.e. 2050, chosen by partners for projections, is a date at which a climatic change trend emerges from natural climate variability. The world climate will have fundamentally changed by 2047 if nothing is done to reduce GHG emissions. Similarly, temperature increases in all areas, but precipitation trends vary.
Short summary of deliverable D1.3. Regional climate change projections is available here
WP2 - Climate impact identification
The objectives of this work-package are (1) to identify based on modelled projections, how future climate scenarios could impact on closed, abandoned and operating mines within regions and (2) to identify, quantify and evaluate those impacts brought about by changes in precipitation, temperature and sudden changes in atmospheric pressure. A methodical approach was agreed upon and implemented by individual partners. All works within WP2 are on-going.
Following tasks have been carried out within WP2 so far:
- Task 2.1 - Identification of physical and chemical impacts due to changes in precipitation
Based on the climate projections, works in Task 2.1. have been focused on the results of changing precipitation, coupled with changes in evaporation – especially how it affects surface run off water & water quality, groundwater recharge, stream flow and changes in composition of mine water. Works in task 2.1 have been divided into three sub-tasks regarding stability issues in both surface features (such as slopes, and tailings dams) as well as old underground workings.
Conclusions so far had identified negative physical impacts caused by changes in precipitation. The physical impacts affecting stability of mine workings and surface structures due to precipitation and floods are mainly related to: overtopping during heavy rainfall events, affecting the stability of the dam; slope stability threatened by fast floodwaters; surface loading caused by extreme flooding over an underground mine; rainstorms and floods cause the phreatic line in the tailings dam to rise which in turn induces seepage damage, producing piping effect by changing the material properties; increased contraction-expansion cycles caused by more extreme wet-dry events.
The physical impacts affecting stability of mine workings and surface structures due to drought which may cause an important indirect impacts. Having a maximum capacity of water stored on site for mining works can increase the risks associated with sudden floods. Correlation between the drought periods and those with higher frequency of sinkhole occurrence. Unstable landforms with insufficient vegetation cover, erosion and mass movement risks occur onsite and sedimentation offsite. Erosion and undermining of the toe of a slope can cause rock falls, landslips or debris flows that can create additional damage.
Short summary of deliverable D2.1. Report on physical and chemical impacts due to changes in precipitation is available here
- Task 2.2 - Identification of physical impacts due to changes in temperature
Within this task, following aspects and impacts of change (increase) of temperature are under examination and relate to the effectiveness of rehabilitation of closed and abandoned mines (i),medium/long term changes in biodiversity (ii), potential for vector disease shift (iii), and gas emissions (iv). The impact on efforts to rehabilitated closed and abandoned mines has been investigated.
Short summary of deliverable D2.2. Report on physical impacts due to changes in temperature is available here
- Task 2.3 - Identification of physical and chemical impacts due to changes in atmospheric pressure
Investigations into the impact of barometric pressure changes have been concerned with the emission of gasses from mines. The work has been carried out in conjunction with the work into the effect of temperature changes on gas emissions. Data from abandoned shafts have been collected on CO2, and/or CH4 and O2 concentrations, and correlated with atmospheric pressure and temperature variations. Local changes in air pressure should be considered as very small differences between very large values. In practice, the baric topography in general (represented by the value dp av.) is the basis for more detailed analysis of pressure variations. The results will be later used to determine the distance from the abandoned, empty shaft where the presence of emitted gases can be detected.
Short summary of deliverable D2.3. Report on physical and chemical impacts associated with changes in atmospheric pressure is available here
WP 3 - Quantitative modeling of climate impacts
The work in WP3 aims to use models to investigate the influence of various facilities or legacies of mining through climate-related changes and to identify the relevant factors. The activities already undertaken focused on determining the study sites, selecting the model tools and setup the models including compilation of the required input data. In addition, the first test calculations were carried out.
- Task 3.1 - Modeling and simulation of environment impacts on mine water quantity & quality
Model works on the influences of climate and water on mine-specific facilities have been carried out with regard to deep mine water, near-surface groundwater and runoff from heaps. The Boxmodel software used to calculate water rise, quantity and quality of deep mine water required modifications in order to be able to take into account climatic influences and their changes in a suitable manner. Existing models were updated, new models were compiled and the first test runs carried out
The focus of the work was the interface between climatic phenomena (temperature, precipitation, etc.) and the water flowing into the mines. This would be solved by a transient calculation of the formation of the groundwater on the basis of daily data. This makes it possible to calculate the inflows into mines depending on the climate. However, the method requires a complex database that is currently only available for one of the intended test sites (3 in Germany; 2 in Poland and 1 in Spain). The methodological investigations therefore concentrate on this location for further work.
Using a Visual MODFLOW model for the dump and the aquifer the influence of a coal mine dump in Poland has been considered. The potential locations for modeling the impact of precipitation on water flow from spoil tips with respect to flooding potential in UK were selected. In addition to that, gathering the data necessary for carrying out modelling exercises on specific sites has been delayed due to the impact of COVID-19 because visiting spoil heaps to obtain data on issues such as ground conditions and vegetation has not been possible.
- Task 3.2 - Modelling and simulation of impacts on surface stability
Works within Task 3.2 have aimed to model the environmental impacts identified in WP2 on surface stability. Two types of numerical models of mining pits and tailings dams are currently being developed for heavy rain leading to a rise in groundwater level and flooding of excavations.
Moreover, the impact of rainfall infiltration on typical open-pit slopes’ stability has been studied. The influence of several geotechnical and geometrical factors was examined. Additionally, all existing data regarding slope of Lake Most, i.e. the area’s hydrology and geology, were gathered and studied. A pilot installation for slope protection, located at the mine waste dumps of the Janina mine site in Libiąż, Poland, was analyzed and presented with consideration of measurements and observations of erosion and stability due to drought occurrence and heavy rains. Preparatory works at a pilot site have been carried out to implement slope preservation of the mine waste dumps against the impact of extreme weather events (such as extreme rainfalls 77,8 mm/day) and extreme drought with duration of more than 4 months with maximum temperature 39oC. This scenario bases on a constant increase of average temperature and annual precipitation in GZW (USCB) area as it was identified in WP1. A technical design for the liquidation of a shaft was prepared, with use of selected backfilling material in terms to predicted mine water inflows due to changes in precipitation. The behaviour of rock mass and the stability of old shafts affected by increased water inflow was numerically simulated and examined. As the work is still ongoing, the results are not expected until end of this year.
- Task 3.3 - Modelling and simulation of environmental impacts on mine gases
Two numerical models, in Ansys Fluent and FDS, showing the relationship between the rate of change of atmospheric pressure, temperature and gas emissions from their data collated from the shafts in Task 2.3 were studied. Analysing the negative change in temperature, it has been indicated that the advection of the cool air mass is a factor that causes air to flow into underground voids. Thus, in the case of a dominant downward trend in atmospheric pressure, such a case will slightly inhibit gas emissions. Moreover, to check variations of gas concentrations at the surface Pyrosim software were applied.
Short summary of deliverable D3.3. Report on developed numerical models relating to mine gas emissions is available here
WP 4 - Risk and impact mitigation and adaptation
The main purposes of WP4 is to develop effective adaptation strategies and monitoring solutions to reduce the impact and vulnerability of sites to climate change, and in turn enhance the sustainability credentials of mining activities, especially when related to mine closure and mine closure planning, and an integrated risk management tool as well as to apply in pilot scale the remedial measures for stabilisation of sealed shaft and mine spoil dump in case of extreme weather events occurrence. Works in WP4 started earlier than planned.
- Task 4.1. Identification and application of impact and risk mitigation/adaptation methods
- Task 4.2. Development of risk management and monitoring strategies
- Task 4.3. An integrated risk management tool
Description of pilot installation – the remedial measures for stabilization of sealed shaft in situation of extreme weather events occurrence – is available here.
Description of pilot installation – the remedial measures for stabilization of mine spoil dump in situation of extreme weather events occurrence – is available here.