While compacting the soil in an air-knife boring, the air line connected to the pneumatic tamper inadvertantly disconnected.

On Saturday November 6, 2010 at approximately 11:15 AM, Stratus was conducting air knife activities on a high school property adjacent to the project site in preparation for forthcoming CPT activities. While the air knife crew (JDK Drilling) was placing the native material back into the borehole and compacting the soil, the pneumatic hose coupled to the tamper (via a Chicago fitting) decoupled at the tamper end.  JDK tamper operator immediately dropped the tamper clear from his body and hands. The loose airline was controlled by the whip check connected between the hose and the tamper.  The second JDK operator was adjacent to the airline valve and immediately closed the valve. The group executed Stop Work and evaluated the overall situation.  No injuries occurred.

After investigation, it was determined that the pin securing the two halves of the Chicago fitting was not placed in the securing hole. JDK was aware of the need to place the pin in the securing hole to ensure the fitting is aligned and to prevent decoupling.  After assessing the equipment and supplies on hand, additional pins were not located on site and the borehole was backfilled and compacted by hand with a manual compaction bar.

This near miss stresses the importance of whip checks and for the placement of securing pins in Chicago fittings.  A sample picture of a Chicago fitting and securing pin is below.