Geophysical mapping of the Rudabánya mine waste rock piles and Hámor Lake

Ore and mineral mining at Rudabánya dates back to ancient times. Initially, sulphide ores and materials of surface oxidation zone were utilized. Later carbonate iron ore was produced here, with additional silver, copper and lead ores. Large-scale iron ore mining began in 1880 and lasted for a century. During the mining activity, millions of tonnes of waste rock material were deposited on the surface near the villages of Rudabánya and Felsőtelekes. Because of technological developments and new ideas the material of the spoil tips – iron oxides and remaining sulphides, barite – can be utilised. Due to Háromkő’s previous successful investigations on the Toka-Creek region [1] and refuse damp near Miskolc [2], the company was requested to take part in the project of “Rudabánya Ore Occurrences Research Development Program for Geological Studies”. The task was: general geological mapping of the area and identifying the site boundary and the inner structure on the heaps. The four areas are the following: Rudabánya No. 1. heap – a “Baritmix” landfill and three areas near Felsőtelekes. The area No. 1 and no. 3 were studied in detail and only exploratory measurements were performed on other two heaps. Considering the extent of fields and quality of materials in the subsurface we combined four geophysical surveying methods: multielectrode profiling, VES sounding, IP sounding, total magnetic field and gradient measurements and GPR. These methods have been successfully applied abroad [3, 4]. During the processing of data measured we determined near-surface resistivity distribution of multi-electrode section and the real resistivity distribution from the VES data as well. From the IP data the types of contamination were determined. The earliest IP sounding, Turai interpreted corrected electric conductivity [5] was introduced for the mapping of contamination. Measuring the total magnetic field and magnetic gradient were successful. As a second example of geophysical mapping, we briefly discuss the resistivity profiling of Hámor Lake. A floating Schlumberger array probe was used on Lake Hámor’s water surfaces and sonar measurement with so-called “fish radar” was utilised within the project of “Diagnostic and Research Work of Miskolc’s Endangered Karst Aquifer”.