| 摘要 |
A utility conveyance (10), such as a pipe, cable or duct, designed for burial in surrounding earth (12) carries a passive warning mechanism (16), preferably a water-soluble dye embedded in the conveyance. The dye, when exposed to moisture (e.g., rainwater in the surround earth) will bleed from the conveyance and discolor the surrounding soil, thus alerting any contractor attempting to excavate in the surrounding area.
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