Reduction of hand-arm transmitted vibration on pneumatic jackleg rock drills

Abstract Transmission of vibration to the operator from percussive vibrating tools is increasingly of concern in industrial and mining applications. Prolonged exposure to high levels of vibration transmitted via the hand causes disorders known as hand-arm vibration syndrome (HAVS). The vascular component of HAVS is called vibration white finger (VWF) and has a debilitating effect on the hand. Vibration at frequencies below 1250 Hz, a tight hand-grip force and cold environments are reported to increase the likelihood of developing VWF. A vibration damping handle design with patents pending that addresses some of the causes of VWF has been developed and retrofits onto jackleg pneumatic rock drills. The handle is decoupled from the drill while maintaining jackleg twist-grip controls on the hand-grip using a combination of sealed self adjusting hydraulic pistons and compliant materials in series, and a new air control valve. The ergonomics of the hand-grip was also modified by the addition of a polyurethane sleeve with a diameter of 50 mm. The new hand-grip reduces direct cold metal contact and minimizes gri
Keywords: Vibration, Hand-arm vibration syndrome (HAVS), Vibration white finger (VWF), Vibrating tools.
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Summary: This paper focuses on a number of interesting results to establish the theory and principle of air-deck blasting. It also gives the mechanism of breakage that takes place in air-deck blasting under varying charge load conditions. With these aspects in mind, the mine management can implement this up-coming technology to enhance safety and higher productivity.
Publication: CIM Bulletin
Author(s): P. Pal Roy, R.B. Singh
Keywords: Air-decking, Presplit blasting, VOD (velocity of detonation), Material decking.
Issue: 1047
Volume: 94
Year: 2001
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Summary: To minimize ore dilution induced by blast movement in surface mines, it is necessary to quantify such movement. This will enable more accurate location of the grade boundaries beneath the surface of a blasted rock pile before excavation. A method has been developed and tested to accurately measure the direction and magnitude of subsurface blast movement. This technique uses a cesium vapour gradiometer and a real-time, differentially corrected GPS system to locate pre- and post-blast position...
Publication: CIM Bulletin
Author(s): G.W. Harris, P. Mousset-Jones, J. Daemen
Keywords: Ore dilution, Blast movement, GPS (Global Positioning System), Field magnetics, Vertical gradient.
Issue: 1047
Volume: 94
Year: 2001
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