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Mine prop jack and method of prestressing a mine prop

a technology of mine props and jacks, which is applied in the direction of props/chocks, mining structures, earthwork drilling and mining, etc., can solve the problems of mortar setting time of several hours and roof pressure too high for conventional roof bolts, and achieve the effect of eliminating the requirement for water and cemen

Inactive Publication Date: 2012-06-14
CANYON FUEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention provides a mine prop jack for prestressing a telescopically expandable mine prop. The jack is placed between the head and foot plates of the prop and is locked in place to apply a constant pressure to the prop. The jack can be easily moved to another site and attached to another prop for use. The invention allows for safe and effective prestressing of the support without the need for tools or water and cement."

Problems solved by technology

Such roof supports are useful in areas where mine roof bolting machines are not practical or the roof pressure is too great for conventional roof bolts.
Another problem incurred with the mortar bag is that the mortar has a setting time of several hours.

Method used

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  • Mine prop jack and method of prestressing a mine prop
  • Mine prop jack and method of prestressing a mine prop
  • Mine prop jack and method of prestressing a mine prop

Examples

Experimental program
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Embodiment Construction

[0010]Referring to the drawings, the telescopically expandable mine prop 10 includes a lower pipe section 11 which telescopically or slidably receives therein upper pipe section 12. Head plate 13 and foot plate 14 are welded to opposite ends of the prop 10 and the prop 10 is thus expandable such that head plate 13 and foot plate 14 respectively engage the mine roof 15 and mine floor 16. A vertical series of apertures 17 are provided in the mine prop 10 in order to receive a lock pin therein to permit preliminary adjustable locking of the mine prop 10 prior to full expansion for prestressing and subsequent locking of the prop 10 after full expansion for prestressing.

[0011]Jack post 20 of the present invention includes upper and lower clamps 21 and 22 respectively which consist of spaced ears 23 that engage opposite sides of prop 10 and are retained in position temporarily by the placement of bolts 24 through aligned apertures provided in the spaced ears 23. This retains jack post 10 ...

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PUM

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Abstract

A telescoping mine prop is prestressed by engaging the prop with a jack and thereby telescopically expanding the prop against opposing surfaces of the mine with the jack. Thereafter the prop is locked in position and the jack is disengaged from the prop for use with the expansion of another prop, thereby leaving the mine prop in a prestressed condition.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates generally to mine roof control, and more specifically, is directed to prestressing a standing support referred to as a mine prop. Such roof supports are useful in areas where mine roof bolting machines are not practical or the roof pressure is too great for conventional roof bolts.[0002]As mining conditions continue to deteriorate due to depletion of easily accessible reserves, greater rock loads from increasing overburden are becoming the norm in mining. In order to protect miners from roof falls the root support or mine prop is prestressed so that the immediate strata does not have the opportunity to begin convergence. Controlling the initial convergence of the strata is critical in roof conditions that have a high degree of creep. Currently there are two methods of prestressing a standing support. One is accomplished with inflatable metal bladders that require a water reservoir and a pump. The second method involves p...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): E21D15/582E21D15/14
CPCE21D15/20E21D15/586
Inventor POULSON, KENNETHGLEAVE, MAURY
Owner CANYON FUEL