Extendable/erectable arm assembly and method of borehole mining

Abstract

An extendable, retractable, erectable arm assembly for housing and supporting a water conduit extending outward from a tool located in a borehole, to a nozzle to produce a high pressure water cutting jet is provided. The arm assembly includes a plurality of interlocking arm segments for housing, supporting and moving the conduit through an angle of about 90.degree. from a stowed position to an operating position. The arm segments include integral, separable hinges capable of being interlocked such that pivotable movement is possible along any side thereof. These segments have mating apertures therethrough to accommodate the conduit. The assembly also includes an erecting device which provides compression on the segments and which gives the arm rigidity during movements. An alignment device is also included which keeps the segments aligned when the arm is deflected. There is also a device which applies tension to the erecting device; thus, allowing the nozzle to remain in close proximity to a surface at which the cutting jet is directed. The assembly also has a launching device designed to turn and lift the arm so that it may be extended and retracted at any angle and position. There is also a device which moves the arm within the tool along the longitudinal axis of the hole. The aforementioned assembly may be incorporated into borehole mining apparatuses and used in borehole mining processes.