Cornerstone Halt Lifted and Company Moves Forward on Share Exchange Agreement

Cornerstone Metals Inc. (TSX VENTURE:CCC) ("Cornerstone" or the "Company")
announces that the temporary suspension of trading of the Company's shares, as
required by the TSX Venture Exchange (TSXV) pending receipt and review by the
TSXV of acceptable documentation in connection with the Company's proposed
acquisition of Copper One USA Inc. ("CO USA"), has been lifted. The Company has
now completed a satisfactory due diligence investigation and is working on
finalizing a Share Exchange Agreement with Copper One Inc. (TSX VENTURE:CUO)
(the "Vendor") to acquire all of the shares of CO USA, Copper One Inc.'s U.S.,
wholly-owned subsidiary. CO USA holds the mineral rights to 6 copper properties
located in New Mexico and Arizona, with the principal property being Lone
Mountain, New Mexico. 


Pursuant to the terms of the LOI relating to this transaction, as amended (see
news releases of March 21, 2013 and May 15, 2013), on closing the Company will
acquire all of the issued and outstanding CO USA shares in consideration for the
issuance to the Vendor of a total of 2,250,000 Cornerstone shares (750,000
shares of which are in recognition of the existing financial assurances that are
in place totalling approximately US$250,000). 


Additional consideration is tied to specific properties as follows (all future
share issuances being subject to further TSXV approval at the time of issue): 




(i)   Lone Mountain- New Mexico:                                            
      Within 30 days of a Definitive Feasibility Study, the Company will:   
      (a) issue 2,000,000 shares;                                           
      (b) pay $1,000,000 in cash or shares (at the Vendor's discretion); and
      (c) grant to the vendor a 0.5% NSR capped at $5,000,000, which may be 
          repurchased for $1,000,000, payable in cash or shares (at the     
          Vendor's discretion)                                              
                                                                            
(ii)  Jerome - Arizona:                                                     
      Within 30 days of a Definitive Feasibility Study, the Company will:   
      (a) issue 500,000 shares;                                             
      (b) pay $750,000 in cash or shares (at the Vendor's discretion); and  
      (c) grant to the vendor a 0.5% NSR capped at $4,000,000, which may be 
          repurchased for $800,000, payable in cash or shares (at the       
          Vendor's discretion)                                              
                                                                            
(iii) Additional Properties - Arizona and New Mexico:                       
      Within 30 days of a Definitive Feasibility Study, the Company will:   
      (a) issue 350,000 shares;                                             
      (b) pay $375,000 in cash or shares (at the Vendor's discretion); and  
      (c) grant to the vendor a 0.5% NSR capped at $3,000,000, which may be 
          repurchased for $350,000, payable in cash or shares (at the       
          Vendor's discretion)                                              



The Company paid the Vendor an exclusivity fee of $10,000 on execution of the
LOI. The Company also agreed to pay the costs of updating the current NI43-101
report on the Lone Mountain property and a property payment owing on the Lone
Mountain property of US$55,000 (which payment was made May 3, 2013).


Cornerstone re-negotiated exploration license and purchase option agreements for
CO USA with the two surface landholders at Lone Mountain that provide surface
exploration access and the option to purchase the surface rights to the lands in
the future.


This transaction will be subject to standard closing conditions for a
transaction of this nature, including but not limited to board and regulatory
approvals.


Lone Mountain will become Cornerstone's principal project in the United States.
Located near Silver City, New Mexico, the Lone Mountain property is situated in
a well-known mining district, 11 km southwest of the Santa Rita-Chino mine and
16 km northeast of the Tyrone mine; both of these mines are large open-pit
copper operations owned by Freeport-McMoRan and both currently produce copper
using the SX-EW technology.


Land holdings on the Lone Mountain property consist of two New Mexico State
mineral leases and 40 unpatented federal mining claims, comprising 619.17
hectares (1,530 acres). Cornerstone will have an undivided 100% interest in the
claims and leases. The Company will retain, through CO USA, State issued Part 4
exploration level permits for up to 176 drill sites and 3 holes per site for a
total of 528 drill holes. 


The Lone Mountain property covers a large tonnage porphyry copper system with
some 25,500 metres of historic drilling in 56 drill holes. It represents a
broadly-explored, (drill hole spacing was approximately 250 metres)
well-mineralized, porphyry-skarn system with multiple, stacked mineralized
targets. Three distinct targets are present; a near-surface zone of copper oxide
mineralization, underlain by a mixed copper oxide-chalcocite zone and finally a
lower copper-zinc skarn zone. Copper oxide mineralization begins approximately
60 metres below surface and continues to over 250 meters below surface. The
combined copper oxide and mixed oxide-chalcocite zone grades from 0.2% to 0.37%
copper over significant widths. The copper oxide and mixed oxide-chalcocite
zones will be the primary interest of Cornerstone, with the aim to in-fill and
justify a NI43-101 resource as quickly as possible.


The mining target is open in three directions. Drilling in 2012 by Copper One
intersected 135 meters of 0.36% copper on a portion of the property that had
never been tested and extended the known mineralization to the south.


The West Jerome property, near Jerome, Arizona, will be Cornerstone's second
priority, consisting of approximately five square kilometers of claims on the
west side of Freeport McMoRan patented lands. The property, in a Volcanogenic
Massive Sulfide camp, is a high-grade, massive sulfide target located 2.4 km
south of the past-producing United Verde (32 million tons grading 4.4% copper,
1.5 oz/t silver and 0.04 oz/t gold). The West Jerome property has attractive
untested TEM geophysical targets.


The Mimbres Property consists of 45 unpatented lode claims and 2,040 acres of
New Mexico State Mining Leases over a porphyry copper-molybdenum deposit and
higher-grade copper-zinc-gold-silver-bearing skarns. It has a large airborne
magnetic signature similar in size and magnitude to the neighboring Chino copper
mine operated by Freeport McMoRan, 8 km away.


The Twin Peaks property near Wickenburg, Arizona is a partially drilled, copper
oxide deposit that has excellent infrastructure and potential for a large
open-pit copper oxide body with very low strip ratio. A surface area measuring
750 metres by 520 metres exhibits veins, veinlets, and stockworks of chrysocolla
and secondary malachite, tenorite, and cuprite and chalcocite hosted by a
pyrite-poor Laramide-age quartz monzonite.


According to the US Geological Survey, the Safford District is the biggest
undeveloped copper district in the world with multiple world-class porphyry
copper deposits. The district is dominated by Freeport McMoRan mining
operations. The West Safford and Teague Springs properties are two
well-positioned projects in the district.


The West Safford property is 11 km west from the producing Dos Pobres mine. It
consists of approximately 2,860 acres of claims, and a 640-acre Arizona State
Mineral Exploration lease. The target at West Safford is a large tonnage
"Resolution-type" porphyry copper target, buried beneath younger alluvium, in
the Safford Mining District.


The Teague Springs property consists of 1,920 acres of claims located further
west of Dos Pobres. The target area is a large tonnage, buried Laramide porphyry
copper-molybdenum-silver-gold system associated with a large, untested IP
anomaly and a Mo-Cu-Zn biogeochemical anomaly. 


Courtney Shearer, interim-CEO remarked, "We are very pleased to have completed
satisfactory due diligence and we look forward to finalizing and signing the
Share Exchange Agreement with the Vendor and proceeding to close the
transaction. CO USA now has the revised agreements with the surface landholders
that provide long term access to explore the claims at Lone Mountain and the
ability to buy the surface rights to the lands in the future. With the
exploration permits from New Mexico regulators, CO USA has the ability to drill
up to 528 holes, which will fully explore the potential of this project.
Cornerstone will be evaluating and prioritizing our exploration strategy on all
the projects as soon as we can and look to move forward on work at Lone
Mountain, NM when the Share Exchange Agreement is finalized and the transaction
closes."


About Cornerstone Metals Inc.

Cornerstone currently owns 100% (subject to 1.5% NSR) of the 12,066 hectare
Spences Bridge Gold Project near Merritt, BC. The Spences Bridge project is an
exploration project focused on gold in the Spences Bridge Gold Belt. 


Cornerstone's objective is to advance exploration / development stage copper and
precious metals properties to production in the Americas. The Company's
management and board core competence is in exploration, permitting, development,
construction, and operation of mining projects.


ON BEHALF OF CORNERSTONE METALS INC. 

Courtney Shearer, Interim CEO & President

Paul S. Cowley, P.Geo., director of the Company is the Qualified Person as
defined in NI43-101, who has reviewed and approved the technical content of this
release.


Forward-looking information 

All statements included in this press release that address activities, events or
developments that the Company expects, believes or anticipates will or may occur
in the future are forward-looking statements. These forward-looking statements
involve numerous assumptions made by the Company based on its experience,
perception of historical trends, current conditions, expected future
developments and other factors it believes are appropriate in the circumstances.
In addition, these statements involve substantial known and unknown risks and
uncertainties that contribute to the possibility that the predictions,
forecasts, projections and other forward-looking statements will prove
inaccurate, certain of which are beyond the Company's control. There can be no
assurance that any forward-looking statements will prove to be accurate, as
actual results and future events could differ materially from those anticipated
in such statements. Accordingly, readers should not place undue reliance on
forward-looking statements. Except as required by law, Cornerstone does not
intend to revise or update these forward-looking statements after the date
hereof or to revise them to reflect the occurrence of future unanticipated
events.


FOR FURTHER INFORMATION PLEASE CONTACT: 
Cornerstone Metals Inc.
Courtney Shearer
Interim CEO & President
403-804-8636
888-255-9604 (FAX)
[e-mail]