A Canadian Natural Resources Ltd. oilsands operation that has contaminated a groundwater aquifer is renewing questions about a technology that has already been linked to another serious leak in northern Alberta. The Alberta Energy Regulator says CNRL reported a break in a well at its Wolf Lake high pressure cyclic steam stimulation project in late October, and that the company later discovered elevated levels of hydrocarbons in the aquifer about 60 kilometres northwest of Cold Lake.