A tool for mining rock by means of undercutting includes an attachment part which defines a center longitudinal axis, and a holder mounted to the attachment part by bearings for rotation relative thereto about the axis. The method includes sensing the pressure in the process chamber, and then controlling the rate of pressure change to achieve a desired rate for a particular vacuum process. A second layer including a light scattering material is provided at least over the first layer, and the surface of second layer has a plurality of protrusions which follow the topology of the light scattering material. The fastening member may be crimped to secure both ends of the loop to the fastening member. The balloon dissector and balloon tip cannula assembly may also include a scope support for insertion through the balloon dissector assembly and dissection balloon and for receipt of an endoscope to view the procedure from within the balloon. or higher is used for the material of the insulating tape.