The environmental regulations on noise and vibration are getting more difficult to meet in urban area every year. The cheapest and fastest rock excavating methods, such as Drill & Blast, hydraulic breaker and diamond saw cutting, are losing their ground to alternative methods, such as hydraulic wedging and coring, which are far more expensive and slower. Regardless of methods, the key to the hard rock excavation still lies on the number of free surfaces created on site. A hand-carry type disc cutter and a notch cutter unit using abrasive suspension water jet for pre-drilled holes, have been developed to create extra surfaces around the holes. The free surfaces created perpendicular to and along the drilled holes eased the excavation of the rock and reduced the vibration and noise delivered through the rock.
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