The company said this week its 18-month assessment of what it called "best available tailings technology (BATT)" options considered 11 locations and five technologies, including dry-stacking. It consulted with First Nations, the Yukon Environmental and Socio-economic Assessment Board and the Yukon Government on the work.

WRN said the BATT study considered environmental, technical, economic, social and failure impacts of tailings and mine waste disposal.

"The selected option impounds tailings and mine waste in a facility constrained by an embankment constructed from cycloned tailings material," it said.

"The location and footprint of the facility are similar to that proposed in the January 25, 2013 Casino project feasibility study."

Further engineering studies will confirm if design enhancements promising reduced "construction, operation and closure risks and less potential environmental impact" can be achieved at costs comparable to the 2013 feasibility study.

Casino has an estimated  4.5 billion pounds of copper and 8.9Moz of gold reserves, and 5.4 billion pounds copper and 9Moz gold resources, to support a projected 55-year mine life. Its previous studies point to good economics driven by a low strip ratio surface mining operation.

WRN was up 3.6% Wednesday at C86c, capitalising the company at $86.7 milion, but has fallen by a third since the start of 2018.