Apparatus for and method of setting pins in mine roofs

Abstract

Abstract A method of installing a pin in a mine roof in which an elongate pin is pressed into the mine roof by a substantially smooth pushing force applied to the pin head, and the mine roof is subjected to a compressive pressure in the area of the pin to force the roof strata tightly together so that the pin will hold the strata in such condition. The compressive pressure applied to the roof is applied before and during the pressing of the pin into the roof and/or applied to the roof through the pin at the time the pin is pressed into the roof. More particularly, the method comprises the steps of disposing the pin in an open-end cylinder with the pin head engaging an internal piston, disposing a block between the mine roof and the open-end of the cylinder, and holding the cylinder against the block and holding the block against the mine roof at the area at which the pin is to be fixed. A compressive pressure is applied to the mine roof through the block by jacks so that the roof strata is forced tightly together and thereby preconditioned. Fluid pressure is applied to the piston and the pin is pressed through the block and into the mine roof under a substantially smooth pushing force. The full pin contact with the roof strata provides increasing holding power, and the pin maintains the roof in the compressed condition. The roof pin includes one or more discs carried by and axially spaced along the pin shank, the discs and shank having a friction connection that enables a slidable axial movement of the discs along the shank when the discs engage the roof block as the pin is pressed into place. The discs have an interrupted peripheral margin that provides interrupted bearing surfaces for reduced friction between the guide discs and the cylinder wall. A pin-setting device includes an elongate cylinder having an open-end and a closed end in which a piston is movably mounted, the pin being located in the cylinder with the pin head seating on the piston. A pair of fluid jacks are located on opposite sides of and attached to the pin cylinder. A pressure plate is carried by the pin cylinder substantially near the open-end, the pressure plate overlapping the jacks and engaging the mine roof to locate the open cylinder end in the predetermined area at which the pin is to be fixed, and holding the block against the mine roof. The jacks exert pressure on the mine roof through the pressure plate and block, and clamp the open-end of the pin cylinder in such position. Upon introduction of fluid into the cylinder, the piston is moved in a direction to press the pin into the mine roof under a substantially smooth pushing force.

Inventors

• 👤 J Alongi
• 👤 G Elders
• 👤 T Schneider

Bibliographic Details