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Abstract The rupture and movement scope of overlying strata increase sharply since the high strength and rapid exploitation of the longwall mining faces；and the spatial structure formed by fractured strata becomes much more complex. The overlying strata would move and interact coordinately when more workfaces exist；hence leading to mining dynamic disasters that defined as spatial structure instability in this paper. Based on the boundary conditions，three basic forms that named OX，F and T structure are identified，respectively. The OX-F-T evolution of the overlying strata is presented that the O-X fracture is the elemental structure of overlying strata and also the boundary of adjacent workface，one side is OX constitute F structure，and both side with OX is T structure. The characteristics and detailed classifications for each type are elaborated. The microseismic system is used for on-site monitoring，single，double and isolated workfaces that represent the OX，F and T structure are selected respectively to research the distribution rules of seismic events；the results confirmed the OX-F-T spatial structure feature. At last，specialized methods are proposed targeted to workfaces with different spatial structures. The research results provide theoretical guidance for dynamic disaster prevention and control in coal mines.
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Received: 10 October 2011
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2012, Vol. 31 
