Environmental Impact Statement for Proposed Gahcho Kué Mine Submitted to Mackenzie Valley Environmental Impact Review Panel

YELLOWKNIFE, Northwest Territories, December 23, 2010 - De Beers Canada Inc. and Mountain Province Diamonds Inc. are pleased to
advise that the Environmental Impact Statement for the proposed Gahcho Kué
Mine has been submitted to the Gahcho Kué Environmental Impact Review Panel
(the Panel) today. The Panel was established by the Mackenzie Valley
Environmental Impact Review Board to undertake the review of the Gahcho Kué
Project.

"This is a major milestone for the Gahcho Kué Project and our submission
marks completion of a significant piece of excellent work done by our
permitting team which includes our environmental and engineering
consultants," said Chantal Lavoie, Acting Chief Executive Officer and Chief
Operating Officer for De Beers Canada.

The Environmental Impact Statement is the document that details
construction of the proposed mine and how the proposed mine will be operated
to ensure it is a sustainable project. The EIS has been assembled to meet the
rigorous Terms of Reference established for the Gahcho Kué Project by the
Panel in October 2007.

"We are another step closer to realizing the Gahcho Kué Mine as a
reality," said Patrick Evans, CEO of Mountain Province Diamonds. "Gahcho Kué
will be the fourth diamond mine permitted in the NWT and the third Canadian
diamond mine permitted by De Beers. The EIS has been prepared to the highest
standard which we expect will facilitate a fair and expeditious environmental
review."

The next step in the regulatory process will be for the Panel to review
the Project's EIS submission and to confirm that the EIS conforms to the
Terms of Reference. When this determination is made, the next steps in the
Analytical Phase of the Environmental Impact Review will commence. Those
interested in the review should contact the Panel at (867) 766-7056.

The Gahcho Kué Project is a joint venture project of De Beers Canada Inc.
(51%) and Mountain Province Diamonds Inc. (49%), and will be the second
diamond mine in the Northwest Territories for De Beers when permitted. De
Beers Canada Inc. is the operator of the Project.

    For further information:

    Cathie Bolstad
    Director External and Corporate Affairs
    De Beers Canada Inc.
    Tel: +1-867-766-7325

    Patrick Evans
    President & CEO
    Mountain Province Diamonds Inc.
    Tel: +1-416-361-3562

For further information: Cathie Bolstad, Director External and Corporate Affairs, De Beers Canada Inc., Tel: +1-867-766-7325; Patrick Evans, President & CEO, Mountain Province Diamonds Inc., Tel: +1-416-361-3562