| 摘要 |
A method of driving a shaft, or tunnel into competent hard rock with shaped charges. An array of shaped charges to nearly conform with the bottom of the shaft, or face of the tunnel, is carried upon a framework which places the charges a proper distance from the bottom or face surface. Detonation causes the shaped charge jets to penetrate and break several feet into the rock to advance the shaft or tunnel. The loose rock may then be mucked out of the shaft, or tunnel, and the operation repeated. A shaft may be driven downwardly or upwardly by these operations.
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