This paper analyzed supporting mechanism of roadway with anchored bolt in small coal pillar and simulated roadway stability and surrounding rock\'s deformation of roadway in small coal pillar.

Analysis of re-failure form of gas pipeline which is enwinded and renovated by glassfiber;

This paper analyzes the main causes of corrosion on boilers' gas pipelines,puts forth the measure of teflon-steel coated thermoplastic inner-cased pipe,which was implemented.

Two rush-repair methods of patching up and sleeve for gas pipeline leakage are introduced.

Thickness testing sensor for gas pipe wall;

The special hydraulic valve taking the place of the stopper for gas pipe has improved the efficiency,decreased the intensity and danger in the operation of gas.