Halet Lake is the common name for a small lake in Northern Ontario used by the operators of Coldstream copper mine to dump half a million tons of sulphide tailings in the mid 1960s.

[1] Halet Lake became known as "Tailings Management Area 2" of the mine after the Department of Lands and Forest provided permission for the dumping.

[1] The dumping occurred on the south west shore of the waterbody[2] between 1962 and 1967, forming a 3-hectare beach of tailings.

[3]: 146  The tailings produced acid and contaminated downstream bodies of water, including Wawiag River and Burchell Lake.

In 2012, EWL Management Limited built a structure to permanently raise the water levels above the tailings dump.