Button Bits:
A moderately abrasive type of bit, Ideal in medium to hard ground conditions where fast penetration is required and straightness is less critical. Button bits are categorized by a variety of criteria: bit diameter, skirt length, skirt diameter, wall thickness, gauge clearance angle, face design and button insert

Steel Fibre Reinforced Shotcrete (SFRS) is shotcrete (spray concrete) with steel fibres added. It has higher tensile strength than un-reinforced shotcrete and is quicker to apply than weldmesh reinforcement. It has often been used for tunnels.
- Addition of Steel fibers into the concrete improves the crack resistance (or