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Laws and mechanisms of slope movement due to
shallowly buried coal seam mining under ground gully
1
Gangwei Fan
*
Dongsheng Zhang Xufeng Wang Xin Lu
School of Mines, China University of Mining and Technology
Xuzhou, P. R. China 221116
fgwcumt@126.com dszhang123@263.net wxf_cumt@163.com mikle8456@163.com
Abstract
Strata behavior associated with shallowly buried coal seam mining under ground gully
is abnormal due to the effect of ground gully on slope movement. Based on the results
of similar material simulation, the laws of slope movement due to mining under gully
were analyzed. Focused on the slope rock, the mechanisms of slope movement
influence upon underground mining were proposed and the respective structural
models were built by means of the numerical simulation and physical simulation. It
pointed out that the influence of slope movement on underground mining could be
controlled to a certain extent by some appropriate measures. The results indicate that
slope rock behaves horizontal sliding and rotation by layers in gully-wards mining
which means mining towards gully, and reverse polygon rotation in gully-away
mining which means mining away from gully. Slope movement associated with
mining under gully is attributed to the free faces existing in underground and ground
gully.
Keywords: shallowly buried coal seam, gully-wards mining, gully-away mining,
slope movement
1 Introduction
Along with the implementation of Western Development in China, the emphasis of coal exploitation
had transferred to the west. As the most representative western coalfield, Shenfu-Dongsheng coalfield,
in possession of 223.6 billion tons coal, 1/3 of whole country in proved reserves, is the biggest coalfield
in China and one of seven biggest coalfields in the world
[1]
. At the transition zone between Loess
Plateau and Mu Us Sand Land, the location of Shenfu-Dongsheng coalfield is characterized by strong
surface relief, sparse vegetation, weak conservation of soil and water, severe water erosion surface,
high gully development and staggered old channels.
Effects of ground surface relief on underground mining, without consideration or high attention in
general designs
[2]
, however, perform sensitive and strong or even play a dominant role in shallowly
buried coal seam mining especially. Along with large-scale exploitation in western coalfield, more and
more mining under gully was conducted in conjunction with a series of abnormal phenomena, such as
sudden destabilization of pillars in pillar recovery, the sudden pressurization degree exceeding that of
first weighting in process of longwall face advance and severe ventilation leakage, which induced many
disadvantageous influences on safety and high effective product. Figure 1 and Figure 2 show
1
Support by Program for New Century Excellent Talents in University (NCET-05-0480)
-1-