Mountain Province Diamonds Announces Positive Gahcho Kué Independent Feasibility Study

TORONTO and NEW YORK, October 21, 2010 - Shares Issued and Outstanding: 72,628,973

TSX: MPV

NYSE AMEX: MDM

Mountain Province Diamonds Inc. ("Mountain Province", the "Company")
(TSX: MPV, NYSE AMEX: MDM) today announced the results of an independent
feasibility study dated October 15, 2010, on the Gahcho Kué diamond project
located in Canada's Northwest Territories. JDS Energy and Mining Inc. ("JDS")
led and prepared the feasibility study, which has been presented to the
Gahcho Kué Joint Venture (JV) between Mountain Province (49%) and De Beers
Canada Inc. ("De Beers") (51%) (collectively, the "Partners").

Financial and Project Highlights:

    - Project IRR including sunk costs           20.7%*
    - Project IRR excluding sunk costs           33.9%
    - Initial project capital                    C$549.5M
    - Working capital                            C$49.4M
    - Sustaining capital including mine closure  C$36.1M
    - Operating costs                            C$48.68 per tonne
    - Project mine life                          11 years
    - Average annual production                  3 million tonnes
    - Total diamond production                   49 million carats
    - Average annual diamond production          4.45 million carats
    - Diamond price                              US$102.48 per carat**

*After taxes/royalties and unleveraged

**The base case model uses an average realized diamond price of US$102.48
per carat derived from the mean average between the modeled values of De
Beers and WWW International Diamond Consultants (based on their respective
April 2010 price books) inclusive of a real 1% escalation over LOM less an
assumed 4% marketing fee.

Gahcho Kué Mineral Reserve Report

Mountain Province today also announced a new Mineral Reserve estimate for
the Gahcho Kué Project. The Mineral Reserve is the Indicated Resource
contained in the proposed open pit mine that can be mined and processed
profitably and is scheduled for treatment in the feasibility study life of
mine plan. The Gahcho Kué Mineral Reserve estimate is summarized in Table 1
below.

Table 1

Gahcho Kué Mineral Reserve Estimate

     Pipe  Classification Tonnes       Grade        Carats
                           (Mt)  (carats per tonne) (Mct)
     5034     Probable     13.2         1.77         23.3
    Hearne    Probable      5.4         2.10         11.5
     Tuzo     Probable     12.6         1.13         14.2
    Total     Probable     31.3         1.57         49.0

Commenting, Mountain Province CEO Patrick Evans said: "The feasibility
study delivers an economically viable, technically credible and
environmentally sound development plan for the Gahcho Kué project. Also, the
IRR exceeds the minimum 15% required under the Joint Venture agreement to
support a decision to develop. Our focus now shifts to completion of the
Gahcho Kué environmental impact assessment, which will be filed with the
Mackenzie Valley Environmental Review Board prior to the end of the year."

The full 43-101 feasibility study will be filed on SEDAR, EDGAR and the
Company's website shortly.

Qualified Person

The feasibility study was prepared by an integrated independent
engineering team led by JDS Energy and Mining. Mr. Daniel Johnson, P. Eng has
reviewed and approved the contents of this release.

Located in Canada's Northwest Territories, Gahcho Kué is one of the
largest new diamond projects under development globally. The project consists
of a cluster of kimberlites, three of which have a probable mineral reserve
of 31.3 million tonnes grading 1.57 carats per tonne for total diamond
content of 49 million carats.

Forward-Looking Statement

This news release may contain forward-looking statements, within the
meaning of the "safe-harbor" provisions of the Private Securities Litigation
Reform Act of 1995, regarding the Company's business or financial condition.
Actual results could differ materially from those described in this news
release as a result of numerous factors, some of which are outside the
control of the Company.

Going Concern

The Company confirms that its audit report and amended financial
statements for the year ended December 31, 2009, and filed in early April
2010, included a going concern qualification in the typical form.

For further information:

Mountain Province Diamonds Inc.

Patrick Evans, President and CEO, Phone: +1-(416)-670-5114

www.mountainprovince.com

E-mail: info@mountainprovince.com

For further information: Mountain Province Diamonds Inc.m Patrick Evans, President and CEO, Phone: +1-(416)-670-5114, www.mountainprovince.comm E-mail: info at mountainprovince.com