Quaterra Delineates High-Grade, Acid-Soluble Copper Zone at MacArthur 

VANCOUVER - Quaterra Resources Inc. reported that angle drilling on a spacing of about 500 feet is defining a large zone of high-grade copper mineralization north of the pit at its 100%-owned MacArthur copper project in the Yerington district of western Nevada.

Hole QM-187, drilled 2,000 feet north of the MacArthur pit, intersected 90 feet of predominantly chalcocite mineralization averaging 1.66% total copper (TCu) starting at a depth of 310 feet. This intercept includes 40 feet assaying 3.49% TCu, which is the highest-grade intercept drilled to date on the property.

Vertical holes were previously drilled on a 500-foot grid to define the overall extent of the horizontal blanket of secondary copper. Angle holes are now being collared in areas with higher grade potential to test high-angle northeast and northwest trending mineralized structures that form an important component of the acid-soluble copper deposit.

"High-grade, acid-soluble copper mineralization appears more abundant than we recognized in the past," said President and CEO Tom Patton. "We believe this Ridge Zone could form part of a higher grade starter pit with robust economics."

As Quaterra's infill drilling program has progressed from west to east across the deposit, several holes began encountering exceptionally high grades of continuous chalcocite and copper oxide mineralization in zones averaging 40 feet or more in thickness. Earlier holes intersected high-grade mineralization in the area now referred to as the "Ridge Zone", but its extent and continuity had been uncertain because several marginally mineralized holes in the initial 500-foot spaced drilling program encountered a system of barren hornblende dikes that cross-cut the area.

Quaterra's infill drilling program is expected to increase the average grade of the MacArthur deposit as new high-grade zones are defined and extended. The Ridge Zone has now been delineated over an area of approximately 2,000 feet by 1,500 feet (see map). It not only has expansion potential to the north, but also to the west where hole QM-180 intercepted 40 feet averaging 1.37% TCu at a depth of 360 feet, and to the south near the northern pit outline where hole QM-193 intercepted 150 feet averaging 0.62% TCu at a depth of 60 feet.

The Company's drilling activities at MacArthur during the first half of 2011 also include step-out drilling, deep drilling, and large diameter (PQ) core drilling for metallurgical samples. Eight step-out holes totaling 4,735 feet (QM-167 through QM 174) have been drilled along the western margin of the deposit in eight holes to extend the outer limits of known mineralization. The results of holes QM-167 through QM-174, drilled on a 500 feet by 500 feet grid along the western margins of the deposit, confirm that MacArthur remains open for the definition of additional acid-soluble copper mineralization. The search for a deep porphyry system at MacArthur continues, with an additional 5,755 feet of drilling completed in three deep holes at the North Porphyry prospect. Since 2008, a total of five holes have tested the North Porphyry target, which has been closed off to the south, east and west, but remains open to the north. Mineralized zones within potassic halos in holes QM-166 to the west, QM-165, and in QM-163 to the east are consistent with those that could fringe a porphyry copper center. Hole QM-100, located between QM-165 and QM-163, encountered one of the best primary copper intercepts yet identified on the project with 65 feet averaging 0.58% TCu at a depth of 1,203.5 feet. Two additional deep holes are pending completion prior to the end of third quarter of this year. A total of 3,285 feet have been drilled in 26 holes to provide samples for column leach tests. METCON Research of Tucson, Arizona, began loading columns from samples of the initial 11 holes in early May. Final results for the column leach tests are expected in the fourth quarter of 2011. Quaterra has a total of 303 drill-hole locations now permitted for drilling on the MacArthur project, including 200 recently approved and bonded locations for infill holes. Work plans for the second half of 2011 include additional infill drilling to define the extent and configuration of the high grade at the Ridge Zone; completion of the initial deep drilling program at the North Porphyry target; and an updated resource calculation and preliminary economic evaluation which will incorporate the results of the column leach tests. The company's address is Suite 1100 - 1199 West Hastings Street  Vancouver, BC V6E 3T5, (604) 681-9059, fax: (604) 641-2740.