Kaho’olawe Island UXO Clearance Project

Neptune and Company, Inc. conducted a statistical analysis of the unexploded ordnance (UXO)/ordnance and explosives (OE) clearance process at Kaho’olawe Island UXO Clearance Project to determine if the contract-required UXO/OE removal was attained. The contract performance goal for clearance was to demonstrate that the clearance process for UXO/OE was achieved (represented by 20-mm or larger rounds, at 46-cm depth, in a vertical orientation to the ground surface were detected, identified, and removed with a probability of 85% or greater and a certainty of 90%). The area represented by Lua Makika was selected for the purpose of this focused investigation. The Lua Makika area reflects a portion of the over 8500 hectares that have been cleared of UXO/OE, but is representative of the clearance process activities and site conditions challenging UXO/OE detection, as this was the most frequently used target area. 

The operational findings, quality control findings, and the assessment/identification findings for this investigation were compiled directly from the site forms and verified with the clearance contractor’s database and the Navy quality control oversight clearance validation. Prior to UXO confirmation by the Assessment and Identification Team, the mean clearance effectiveness for UXO/OEs is 92% with a 90% lower confidence limit of 85%. When the false positive UXO/OE findings of the Assessment and Identification Team are taken into consideration, the mean UXO/OE clearance effectiveness is 95% with a 90% lower confidence limit of 88%. In both instances the performance goal of an 85% probability of detection with a 90% certainty has been meet. To provide additional perspective, only one actual UXO item, a 10-pound practice bomb, was detected during the quality control surveys and confirmed by the Assessment and Identification Team. 

In addition, this investigation had the goal of predicting the potential number of UXO/OEs remaining in Lua Makika after inspection by the Assessment and Identification Team. The mean number of potential UXO/OEs remaining based on the estimated level of process performance is 4, with a 95% upper confidence limit of 13. Therefore, the UXO/OE clearance process used for Lua Makika met and exceeded the UXO/OE contract performance goal.