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Przykłady likwidacji płytkich wyrobisk stwarzających zagrożenie dla powierzchni terenu na podstawie doświadczeń zagranicznych

Strozik G.

Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie

2016

nr 6

23--30

Deformacje powierzchni terenu stwarzają zagrożenie dla zabudowy i infrastruktury technicznej obszarów zurbanizowanych. Jednym z podstawowych obszarów działań w zakresie jego eliminacji jest likwidacja płytkich wyrobisk górniczych. W artykule przedstawiono wybrane przykłady działań zmierzających do eliminacji zagrożenia występowaniem nieciągłych deformacji powierzchni terenu, podejmowanych w innych krajach.

Mining activity leads to degradation of mine lands due to their deformations, including the most dangerous discontinuous deformations. In the early stage of industrial revolution in countries leading in coal production, thousands of mines operated mostly in shallow coal beds, which were easy available by mine techniques of that time. As the result of mine operations in shallow coal seams, large sinkholes and other forms of land deformation occurred, which could affect large areas of lands (Fig. 1) or reach unprecedented dimensions (Fig. 2). To eliminate the risk of sinkhole occurrence and damages of land objects, a range of filling techniques of mine voids have been developed. To the most advanced ones, belong pressurized grouting with use of fly ash – cement slurries of strictly controlled physical properties. However, efficiency of mine voids elimination corresponds with significant costs of land preparation. The most cost-consuming but also completely confident seems to be the open-pit method, in which the coal seam has to be exposed and then fully cleared from old mine operations remnants (Fig. 3). Particular attention must be devoted to old mine shafts, which due to their depth and direct connection to surface may create extremely high risk of land structure damages. The problem of old mine shafts has been discussed on an example of catastrophic collapse of rocks into voids remained in an old shaft after its insufficient backfilling in the past (Fig. 4). Not to overrate in efficient surface protection on post-mining areas is also to have reliable information about potential hazards before any further activities on an effected land piece started. A good example of such a comprehensive data base on old mining operations has been developed in the city of Aachen, Germany. During the last half of the century technologies of filling of underground voids underwent development from typical mine hydraulic backfill, through injection of precisely composed grouts – in terms of flow properties and mechanical behaviour after placement and solidification, up to clearing of shallow mine remnants with use of open-pit operations. Due to high costs of mine lands reclamation works, for each case of underground voids filling, technology and range of works must be thoroughly designed, where also good identification of underground conditions id of great importance.