With Chengchao Iron mine as the engineering background, the necessity and importance of investigating the serious collapse of mine pass are discussed.

以程潮铁矿为工程背景，首先论述了严重垮冒采区溜井研究的必要性和重要性。

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In addition to several House and Senate subcommittees, the Justice Department and Securities and Exchange Commission are investigating Enron's swift collapse and its decision to file for Chapter 11 bankruptcy protection December 2, 2001 -- the largest such filing in U.S. history.

CNN: Enron's ex-CEO will not testify Monday