The rational selection of the technique parameters played an important role in the effective recovery of top coal.

放顶煤回采工艺参数的合理选取，对顶煤的有效回收起着重要的作用。

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On the basis of analyzing stress shell, the mechanical essence that top coal performs a function of bedding is demonstrated.

基于对应力壳体的发现和开展的一系列分析，揭示了综放采场顶煤“垫层”作用的力学本质。

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The rock movement between the horizontal section of the top coal caving and inclined slicing of the top coal caving was analyzed.

运用相似材料模拟和数值计算的方法，对水平分段和倾斜分层放顶煤开采引起的围岩移动特征进行了比较。

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AEP, of Columbus, Ohio, is one of the nation's top coal burners and stands to be among the companies hardest hit by tougher EPA rules.

WSJ: EPA Tangles With New Critic: Labor

James Rogers, chief executive of Duke Energy, has called it the "fifth fuel"--on top of coal, natural gas, nuclear power and renewable resources.

FORBES: Magazine Article

James Rogers, chief executive of Duke Energy (nyse: DKE - news - people ), has called it the "fifth fuel"--on top of coal, natural gas, nuclear power and renewable resources.

FORBES: Greener Than Thou