A practical kind of dismantle pillar device used on aluminum alloy hydraulic prop;

Measures of mining the full height by adding the length of single prop once;

Depending on this instrument, the fault can be noted in time by detecting the pressure of the single prop uninterrupted.

In order to research support technology of gob-side entry retaining under limestone roof,according to the characters of large flap top and slow subsidence for limestone roof,the paper established the roof cutting mechanical model of gob-side entry retaining and designed quantitatively the support parameters for untied roof cutting of anchor and single prop.

Design method and technical features of monitoring system with higher performance,developed recently for checking sealing quality of single hydraulic props are stated in this paper.

Recondition hydraulic prop with expansion seal rings of F form;

Base on the prediction and control of the bumping pressure,the paper provided the protective measures for the hydraulic props at the pilot support section of the coal mining f.