Pacific Bay Minerals Ltd.: Strong Rare Earth Values at Chacho Show High Ratio of Heavy REE


VANCOUVER, BRITISH COLUMBIA–(Marketwire – May 19, 2010) – David H. Brett, President and CEO, Pacific Bay Minerals Ltd. (TSX VENTURE:PBM) (the “Company”) reports that assay results from a recently completed reconnaissance exploration program at the Company’s 100% owned Cueva del Chacho claims in La Rioja Province, Argentina, confirmed the property’s strong potential for Rare Earth Element (“REE”) exploration. Values up to 0.33% Total REEs (“TREEs”) were obtained, with heavy rare earths comprising up to 71% of the contained TREEs. Heavy REEs (“HREEs”) are economically more attractive and rare than light REEs. A detailed summary of the more significant results is inserted below.

The strong REE values were obtained through an initial collection of 39 samples over an area of roughly 6 square kilometers on the Cueva del Chacho Property in both coarse sediments and in leucocratic granite. The hosts and controls of this mineralization are now better understood as a model for future exploration, and the property is being expanded accordingly.

“Unlike many REE concentrations, the heavier rare earths have not been depleted, with the exception of Europium,” said project geologist Dr. Richard Culbert, Ph.D. “Ratios of heavier to lighter elements, have maintained values similar to those reported for crustal averages. The heavy rare earths comprise an average of 29% of the total rare earths, ranging up to 71% if Yttrium is included, and an average of 14% with a high of 44% if it is not.”

The asterisk * represents those samples that have been submitted for petrographic analysis to definitively determine rock types.

Sample # TREE + Y (PPM) % TREE + Y % HREEs  Lithology
CC 21 3,333 0.33% 26.2% altered grit*
CC 6 2,821 0.28% 38.3% arkosic grit
CC 20 2,557 0.26% 34.1% wash sediment
CC 12 2,113 0.21% 23.6% altered grit*
CC 30 1,592 0.16% 21.1% altered grit*
CC 31 1,170 0.12% 27.4% altered grit*
CC 29 1,103 0.11% 19.4% dark siltstone
CC 5 1,024 0.10% 33.2% dark siltstone
CC 13 886 0.09% 24.0% black silty phyllite
CC 27 818 0.08% 71.9% fissile siltstone
PX 1 799 0.08% 31.7% fine intrusive
CC 22 732 0.07% 38.3% rusty alteration
CC 26 543 0.05% 31.3% grits

A geological report prepared by Dr. Culbert on the Cueva Del Chacho property including the recent work can be downloaded from the Company’s website at

About Pacific Bay. Pacific Bay has a diverse portfolio of uranium, silver and base metals properties, including extensive holdings in Quebec’s Otish Mountains Uranium region and the San Jorge uranium basin in Chubut Province, Argentina. Pacific Bay’s strategy is to explore its properties mainly through strong partnerships, such as Strateco Resources Inc. (Quebec) and UrAmerica (Argentina).

The technical information contained in this news release has been reviewed and approved by Dr. Richard Culbert, PhD., P.Geo. a consultant to the Company and a Qualified Person under policy NI43-101.

Pacific Bay Minerals Ltd.

David H. Brett, MBA, President & CEO

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this news release.