Freeze Optimization Study

While the remediation plan proceeds through the regulatory process, the Giant Mine Remediation Project Team is conducting a Freeze Optimization Study at Giant Mine on one of the underground chambers that contains arsenic trioxide waste.

A mine worker inspects the underground pipes used for the frozen block method, which have started to get covered in ice.

This study will provide additional information to develop an optimum ground freezing process. The Project Team will use data from the study to inform future design decisions for the frozen block method. Thus far, the optimization study has provided information about the frozen block method such as power requirements, rate of freezing, pipe diameter, drilling requirements, as well as more accurate cost estimates.

In June 2009, the Project Team constructed a freeze plant and inserted pipes around one of the chambers. The study became operational in early 2011. Since then, the rock surrounding the chamber under study has frozen faster than predicted. The study provides real time information on the speed of freezing and what types of technologies and methods work best in the northern environment. By varying the freezing process, the Project Team monitors what happens when changes occur with the system; for instance, to study how fast the rock freezes under various combinations of passive and active cooling processes.