Grouting of old flooded workings at M. Mayerova Mine in Czechoslovakia

Abstract

The paper is concerned with the design of a surface mining operation above a waterlogged underground mine workings in order to prevent ingress of water and control mine water pollution. The site of investigation was situated at M. Mayerova Mine, near the city of Karlovy Vary, Western Czechoslovakia which was operational at the end of 19th century. These mine workings were abandoned and subsequently, presented the a problem of eliminating flooded mine workings encountered in Jozef Seam at a depth of 176 m and two 4 m. diameter, No. 2 and No. 5, vertical mine shafts. The proposed mining operations were planned to extract overlying Antonin Seam at a depth of 88 m. below the surface by open casting technique and to prevent ingress of water into the planned workings.

This problem had been complicated by a hydraulic connection of flooded workings of the Jozef Seam, recharged from the intersected fault zone, with regional reserves of mineral thermal springs of the city of Karlovy Vary through fissured sandstones and quartzites underlying the coal layer.

For resolving the problem and in accordance with the project report and methodology of Integrated Grouting Technique of P/A Spetstamponazhgeologia (STG), Geoindustria Enterprise, Czechoslovakia has conducted injection of the designed volume of clay-cement grout into the flooded workings. The grout was pumped through surface drilled boreholes under specified regimes. As a result, the inflow to the Jozef seam workings was reduced from 0.5 m³/min to 0.0002 m³/min, ground water temperature fell down from 31°C to 18°C. The paper deals with the actual data of this original project.