Remote Surveying of Underground Cavities Excavated by Jet Boring

Abstract

Cigar Lake is a high-grade uranium deposit, located in northern Saskatchewan, Canada. In order to extract the uranium ore remotely, thus ensuring minimal radiation dose to workers and also to access the ore from stable ground, the Jet Boring System (JBS) was developed by Cameco Corporation. This system uses a high-powered water jet to remotely mine out cavities. Survey data is required to determine the final shape, volume, and location of the cavity for mine planning and development. This thesis provides an overview of the challenges involved in remotely surveying a JBS-mined cavity. In particular, it studies range finding sensors that are relevant to mining applications and their attributes. As an alternative to sensors used for remote cavity surveying, it evaluates the potentially advantageous features of a time-of-flight (ToF) camera. Data was collected from inside a test cavity in a variety of experimental environments meant to simulate conditions in a real Cigar Lake cavity. Field data was collected from the core shack at Cigar Lake and from an open stope at Rabbit Lake. Advanced data analysis techniques such as registration and segmentation are also explored for application in cavity surveying. The data from the ToF camera was evaluated with respect to the survey systems slated for use at Cigar Lake and the advantages for its use in the post cavity survey are shown.