Down reaming apparatus
Drag bit excavation
Dual auger continuous mining machine
Earth discharging device for upward-facing shield machine
Excavator and conveyor of an underground pipeline jacking appara
Excavatory machine for use in coal and other mining opertions
Hopper and hood combination for tunneling machine and tunneling
Hydraulic hammers hydraulically driven impactor
Hydraulic muck handling system for tunnel boring machine
Hydraulic-mechanical coal mining combine
Impact tunneling machine with cutters spaced for equal work
Machine for mining tar sands having rearwardly directed exhaust
Machine for mining thin seamed hard material in-situ between adj
Method and apparatus for boring and shearing of rocks
Method for replacing cutters of tunnel-excavating machine,...
Milling engine for excavating trenches in the ground
Mining machine
Mining machine having an extendable and retractable rotor...
Mining machine having vertically movable primary and secondary c
Mining machinery with guideway for relatively movable cutting un