The company has been working with British Columbia regulators and First Nations to gain access to additional water sources needed to keep the operation in business.
This comes after a temporary suspension over the winter as abnormally cold temperatures froze its available water sources.
Under a string of approvals, Centerra is now able to pump from groundwater wells within Mount Milligan's tailings storage facility (TSF), as well as from a single groundwater well outside of the TSF for the entire life-of-mine.
The company is also allowed to pump up to 15% of the base flow from Philip Lake 1 until November 15. An application to further extend the pumping from Philip Lake 1 for the winter is currently under review.
Centerra said it is also preparing applications needed to draw water from additional longer-term sources until 2020, including access to other wells within a radius outside the TSF and from Philip Lake 1 and Rainbow Creek.
The company has also adopted a new methodology for assessing viable water sources it could draw from after 2020, for the remaining life of the operation.
It cautioned that the interim measures would help, but not meaningfully meet the mine's outstanding water needs. Should there be delays in the regulatory process to approve the medium-term and long-term water sources, it could have a significant negative effect on the company's production at Mount Milligan, future cash flows, earnings and financial condition.
The company's stock closed up 2.07% on Friday, at C$3.95 (US$3.03) a share, after losing more than 11% since the start of the year, giving it a market value of about $8.13 billion.