MINE CLOSURE IN GYÖNGYÖSOROSZI AND RECSK
The remediation of the environmental damage caused by the mining of base metal ores in Gyöngyösoroszi and Recsk
To comply with the emission limits of discharged water from the water treatment facility, heavy metal content in the effluent water escaping from mining structures is reduced, which relevant for the task of the permanent abandonment of ore mining.
5350 m long
reopening of the adit (Altáró)
boreholes backfilling with ash
Mecsekérc Ltd., within the framework of the project started in 2004, conducted an environmental baseline study, made the damage inventory report, examined the hydrogeological impact of the mine closure by a numerical hydrogeological model, which had been the base of the environmental impact assessment required for issuing the environmental license. As a main contractor between 2006 and 2012, Mecsekérc Ltd. had to re-open the designated areas of the Gyöngyösoroszi and Mátraszentimre mines for damage remediation and the disclosed locations had to prepared to be backfilled with ash from power plant as part of the mine closure works. Mecsekérc Ltd. takes part in the mine closure activities as a subcontractor conducting mining and geological design and expert tasks, performing hydrogeological tests in the mines, controlling the quality criteria of backfilling. In addition, the operation of a monitoring system and carrying out laboratory assays in the surface areas affected by the abandonment works are also done by Mecsekérc Ltd. for the whole period.
Within the course of preparatory works required for the permanent closure, all the surface facilities of a mine were built in Mátraszentimre, which are capable of supplying the planned works. The excavation of underground workings started with the reconstruction of a partially backfilled incline shaft and a 340 meters deep vertical shaft backfilled to its full length. Simultaneously with the shaft sinking activities, the re-opening of the 5350 meters long „Altáró” adit creating a passage between the two mining sites was done, which provided ventilation, power and material supply along with the undisturbed escape of water to the water treatment facility. The re-opening of the main routes and the construction of necessary infrastructure was then followed by the reconstruction of the excavation levels of the Mátraszentimre Mine, and the preparation for their backfilling.
Boreholes were supposed to be drilled between the levels to facilitate the backfilling, also mechanical equipment, backfill barriers, water drainage system and monitoring system were installed to enable the backfilling with wet coal fly-ash, therefore reducing the quantities of contamination sources and improving the quality of escaping water.
The plan to backfill the excavations with ash was to start it from the bottom and proceed upwards. The construction of the drainage system in the „Altáró” and its refill marked the end of the works. The surface activities following the backfilling are to be finished with the demolition of the surface facilities and the reclamation of the area.
340 m deep
restoration of the vertical shaft