| 摘要 |
A mine roof support system for use with bore holes having diameters at betwe en about 1 to 1 3/8 inches includes an elongated metal anchor rod or cone bolt, a threaded fastener and a grout or resin composition used to secure at least part of the anchor rod in a pre-drilled bolt hole. The anchor rod includes an externally threaded outer proximal end portion which is provided with one or more enlarged frustoconical shaped projections. The innermost distal end of the anchor rod further includes at least one axially extending projection which, in a simplified construction, is formed as an elongated tongue shaped member which presents generally planar major side surfaces. The frustoconical shaped projections preferably taper i n the direction away from the outer proximal end portion of the anchor rod at an angle of about 3.5.degree., inclined relative to the longitudinal axis of the anchor rod. The tongue shaped member defines at least one, and more preferably two generally opposing major side surfaces which extend in t he axial direction between about 4.5 and 7 cm.
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