Portal Blast Formally Launches Underground Gold Mining at Klondex′s High-Grade Nevada Gold Mine, Fire Creek

Klondex Mines Ltd. (TSX: KDX) is proud to announce the official start of
underground mining at its high-grade Fire Creek mine site in Northern
Nevada. Yesterday afternoon Klondex completed the inaugural blast of its
underground decline at the mouth of the Fire Creek portal.

Klondex plans to drive a 1,113 meter (3,650 foot) decline to access Fire
Creek′s Main Zone mineralization to enable further evaluation of the
resource at depth as well as for bulk sampling production. Including the
decline and all development, maintenance and support requirements,
Klondex expects to complete a total of 1,974 meters (6,475 feet) of
underground development in 2011.

Klondex anticipates first gold production from bulk sampling by year-end
2011, with production increasing in 2012 and beyond. The decline will
also provide in fill drill sites to further test Main Zone
mineralization, providing valuable data for underground development and
Klondex′s mineral resource.

Fire Creek has shown strong indicators of continuity and high grades
favorable to underground mining. The project has low capital costs and
offers high potential operating margins. In the underground development
Klondex is utilizing small-scale mechanized mining performed by Small
Mines Development (SMD), an experienced and respected underground
contract miner. KDX plans to utilize toll processing of the bulk sample.
The outsourcing of mining and processing activities, under the close
supervision of KDX′s experienced Nevada team, serves to limit capital
investment while ensuring the program is able to meet its development
timelines and production schedule. For additional information or photos
of the development activity please visit www.klondexmines.com.

Plans for 43-101 Resource Update

As previously announced, Klondex plans to update its 43-101 resource
estimate by year-end 2011. The resource update will incorporate over
48,000 feet of additional surface drilling data from Klondex′s 2009 and
2010 drill programs, results to date from this year′s 59,000-foot
surface drill program and available data from underground in-fill
drilling.

As of April 28, 2011, Klondex Mines had approximately 36.6 million
shares issued and outstanding, approximately 43.2 million shares on a
diluted basis, and approximately CDN $14.5 million in cash and an
additional $10 million available on demand.

About Klondex Mines (www.klondexmines.com):

Klondex Mines Ltd. is focused on the exploration and development of its
100% owned high-grade Fire Creek gold deposit in North Central Nevada.
Fire Creek is a compelling, low-Capex mining prospect that is well
located near power, transportation, mining infrastructure and several
milling facilities. Klondex has identified the following NI 43-101
compliant resource at Fire Creek:

*The resource is approximately 98.3% gold and 1.7% silver and reflects a
cutoff grade of 5 grams per tonne. 60 units of silver are equivalent to
one unit of gold.

Investor:

Klondex Mines Ltd.

Bryson Goodwin,
604-341-1531

brysongoodwin@shaw.ca

or

Jaffoni
& Collins

David Collins, 212-835-8500

KDX@jcir.com