Update on Lisbon Valley Mine Production

Denver, Colorado, May 23, 2007 - Constellation Copper Corporation ("Constellation" or the "Company") (TSX: CCU) wishes to report production and operating activities at its Lisbon Valley copper mine located in San Juan County, Utah.

Copper production of 2.2 million pounds in April 2007 was the highest since production began in April 2006, and represents a 24% increase over production in March 2007.  Copper sales in April 2007 totaled 2.2 million pounds at an average realized price of $3.43 per pound.  Cash operating costs for April were $1.80 per pound, down from the first quarter 2007 average of $1.92 per pound

Ore through the crushing and conveying/stacking system in April 2007 averaged 14,800 tons per day, an increase of 13% over average ore throughput in March 2007.  Pregnant leach solution (PLS) flow in April 2007 through the solvent extraction (SX) plant averaged 4,952 gallons per minute (gpm), reflecting the successful conversion to a parallel flow configuration in the plant in late March 2007 that targeted capacity of 5,000 gpm.  The flow rate represents an increase of 40% over PLS flow rates in March 2007.  The improvements in plant performance reflect improved operating conditions with the onset of warmer weather and the successful conversion of the SX plant to higher flow capacity.

Cumulative copper recovery (as a percentage of total copper placed on the leach pad since mining commenced) has reached 44.3% compared to cumulative recovery of 55.4% projected in the feasibility study.  At this time we expect to achieve the projected recovery, although it will take additional leach time. 

Although we are experiencing slower leach kinetics than anticipated, the main constraint on achieving full production capacity remains the ongoing inability of the material handling system to deliver budgeted ore tons to the leach pad on a regular and consistent basis. We continue to evaluate and implement ways to improve the ore throughput rate.  One such improvement started on May 13, 2007, after a failure of the drum agglomerator, which mixes the crushed ore with sulfuric acid before it is delivered to the leach pad.  Since initial installation the agglomerator has been the cause of approximately one-third of the total downtime experienced in the material handling system.  Improvements and repairs to the agglomerator, designed to improve the reliability of the unit, curtailed loading of ore to the pad for eight days. The agglomerator is back on line and running smoothly. Repairs were completed safely and without incident.  However, the down time will negatively impact copper production for the balance of the second quarter of 2007 and we have adjusted our quarterly production guidance to 6.4 million pounds.

Construction of the Phase 3 leach pad expansion and the intermediate leach solution (ILS) pond is currently in progress.  The pad expansion will allow the Company to place more ore under leach and the ILS pond will allow recycling or "stacking" the lower-grade leach solutions coming off previously leached portions of ore in order to increase the grade of the pregnant solutions reporting to the SX plant.

The Company is pleased to also announce signing of a new long-term acid supply contract with its primary supplier of sulfuric acid.  The new contract terms, effective April 1, 2007, eliminate indexing the cost of sulfuric acid to the price of copper.  The new price is based on current market rates and provides the Company long-term customer status.  Eliminating the copper price participation formula is expected to have a significant positive impact on the Company's cost of production.

We look forward to continued improvement as we ramp up towards full production capacity at the Lisbon Valley mine.

For further information please contact:

Constellation Copper Corporation
Gregory A. Hahn, President and CEO
Michelle Hebert, Manager-Corporate Affairs
Tel: (720) 228-0055
Toll Free: 1-877-370-5400
Fax: (303) 863-1736
info@constellationcopper.com
www.constellationcopper.com

Renmark Financial Communications Inc.
Neil Murray-Lyon : nmurraylyon@renmarkfinancial.com
Barbara Komorowski : bkomorowski@renmarkfinancial.com
Media - Vanessa Napoli : vnapoli@renmarkfinancial.com
Tel.: (514) 939-3989 
Fax : (514) 939-3717
www.renmarkfinancial.com
 

This press release contains certain forward-looking statements. In certain cases, forward-looking statements can be identified by the use of words such as "plans", "expects" or "does not anticipate", or "believes", or variations of such words and phrases or statements that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur" or "be achieved".   Forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.  Such factors include, among others, risks related to changes in commodity and power prices, changes in interest and currency exchange rates, inaccurate geological and metallurgical assumptions (including with respect to the size, grade and recover ability of mineral reserves and resources), unanticipated operational difficulties (including failure of plant, equipment or processes to operate in accordance with specifications, cost escalation, unavailability of materials and equipment, delays in the receipt of government approvals, industrial disturbances or other job action, and unanticipated events related to health, safety and environmental matters), political risk, social unrest, and changes in general economic conditions or conditions in the financial markets.  Although the Company has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking statements, there may be other factors that cause actions, events or results to differ from those anticipated, estimated or intended.  There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materi ALLY FROM THOSE ANTICIPATED IN SUCH STATEMENTS.  ACCORDINGLY, READERS SHOULD NOT PLACE UNDUE RELIANCE ON FORWARD-LOOKING STATEMENTS.