Grouting of Horizontal Holes in Coalbeds.

摘要

The report describes research to evaluate materials and develop a new technique for packing holes in which a semiliquid and/or rigid type grout could be placed in the hole to provide satisfactory sealing. Horizontal holes are drilled underground into coalbeds to control methane flow from ribs and active face areas and to make gas pressure measurements in coal beds. The study recommended that (1) packers set nearest the rib wall should be at least three times drift width or five times coal thickness and from the rib wall,whichever is greater; (2) grouting pressure should not exceed 0.4psi/ft times feet of overburden; (3) mine water and actual grouting materials to be used should always be checked for setting times before the grout job; (4) the packer system as designed should be used in 3-inch horizontal holes with either the semiliquid or rigid grout materials;and (5) the rigid grout tested using a salt-saturated portland-gypsum-cement blend was satisfactory for use in boreholes of coalbeds. (Author)