SUMARRY
Structural model of the Bố Hạ coal mine on the bases of new
deformation study
Vũ Xuân Lực, Nguyễn Công Thuận
The Bố Hạ
coal mine area is structurally complicated. The area had been studied by many
geological works with different results, which have caused many difficulties
for the orientation of coal mining activities. New research results show that Bố
Hạ coal mine area was heavily affected by at least 3 deformational
events, in which the First deformational phase was taken place in ductile to
brittle-ductile environment, forming large scale shear systems with significant
displacement and flexural tight to isoclinal folds. The second deformational
phase includes the reverse shear zones, truncated, displaced and refolded the 1st
phase’s structures. The third deformational phase produced sinitral strike-slip
shear zones that modified the previously formed structures. As such, the geometry
and orientation of the coal seams in the area were strictly controlled by the
development and interference of the aforementioned generations of structure and
therefore are very complicated, which are different from previous geological
interpretation. The results of this study show that in order to properly
construct a structural model of the coal seams, both on the surface and at
depth to guide in exploiting the deep coal seams, it is necessary to have
detailed and qualitative studies on the regional structure and coal seams.
Keywords: Bố Hạ coal mine, structure of
coal seams, shear zone, deformation phase.