A Novel Wireless Measurement While Drilling System for the Detection of Deeply Buried Unexploded Bombs (UXBs)

Abstract

The problem of Unexploded Ordnance/Bomb (UXO/UXB) affects most big cities in UK and Europe. It is estimated that 10% of aerially dropped bombs failed to explode. The heavy weight of the bombs allowed them to penetrate the ground to a depth that may exceed 14 m. The disturbance of these bombs could result in fatal explosion and represents a serious danger to construction and foundations workers. Current methods for deep bomb detection include predrilled and pushed methods. The pushed method is the preferred technique but it cannot penetrate hard ground. The alternative is the predrilled method that employs a more powerful rotary drilling method to drill and scan the borehole in stages. However, it is very time-consuming and costly. This paper describes the development of an instrument equipped into a rotary drilling rig, which captures, transmits and records earth magnetic field wirelessly while drilling. The proposed system allows UXO detection in real time whilst drilling in various types of ground conditions and provides faster, safer and cheaper method of UXO detection overcoming the limitations of the existing methods. In order to further improve the safety of deeply buried UXB clearance in hazardous environment, this solution can be attached to an autonomous vehicle or robot while data can be remotely collected. Hence, this work focuses on designing a sensor system that can identify deeply buried underground bombs and can be integrated into a mobile robotic system.

Multiple challenges are associated with the development of the proposed solution, mainly: strong magnetic noise interference caused by surrounding metal on the measurements, real time data transmission and the very harsh and noisy drilling environment. This paper addresses the telemetry challenge.