WINNIPEG, Manitoba, Dec. 19, 2007 (PRIME NEWSWIRE) -- Mainstream Minerals Corporation (TSX-V:MJO) is pleased to announce the closing of a non-brokered private placement of $1,000,000 through the sale of 2,380,948 Units at $0.42 each to the MineralFields Group.

Each Unit consists of one flow-through common share, and one non-flow-through common share purchase warrant having a term of 24 months from date of issue and an exercise price of $0.75 in year 1 and $1.00 in year 2. In arranging this financing, First Canadian Securities(r), a Division of Limited Market Dealer Inc. ("the Finder"), received a 5% cash finder's fee and 24 month finder's fee units equal to 10 % of the number of units subscribed for, at an exercise price of $0.75 per unit. Each finder's fee unit entitles the holder thereof, upon exercise, to one non-flow-through common share and one non-flow-through common share purchase warrant having a term of 24 months from date of issue and an exercise price of $0.75 in year 1 and $1.00 in year 2. Mainstream Minerals Corporation also paid to the Finder a due diligence fee of $20,000, equal to 2% of the aggregate proceeds from the non-brokered private placement. The shares issued in connection with this offering are subject to a four-month plus one-day hold period.

Mainstream Minerals Corporation intends to utilize the proceeds from this non-brokered private placement for the ongoing exploration and development of its joint-ventured Bobjo Mine Property and at its other projects.

"Mainstream Minerals is very pleased to have completed this second financing in 2007 with the MineralFields Group," said Neil Sullivan, President & CEO. "Our working relationship with the MineralFields Group is proving to be a positive factor that enables us to continue with the ongoing exploration and development of our holdings in the Red Lake Gold Camp of Northwestern Ontario."

About MineralFields, Pathway and First Canadian Securities(r)

MineralFields Group (a division of Pathway Asset Management) is a Toronto-based mining fund with significant assets under administration that offers its tax-advantaged super flow-through limited partnerships to investors throughout Canada during most of the calendar year, as well as hard-dollar resource limited partnerships to investors throughout the world. Pathway Asset Management also specializes in the manufacturing and distribution of structured products and mutual funds. Information about MineralFields Group is available at www.mineralfields.com. First Canadian Securities(r), a division of Limited Market Dealer Inc., is active in leading resource financings (both flow-through and hard dollar) on competitive, effective and service-friendly terms, with investors both within, and outside of, MineralFields Group.

About Mainstream Minerals Corporation

Mainstream Minerals Corporation is a mineral exploration and development company focused on precious metal mining properties with economic potential, with the aim of bringing such properties to commercial production. The Company's portfolio of properties is primarily located in the prolific Red Lake Gold Camp of Northwestern Ontario. The properties include -- (i) 50% of the Bobjo Mine project, (ii) 100% of the Dixie Lake North project, and (iii) 50% of the Woman Lake North of South Bay project.

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release. Some of the statements contained in this release are forward-looking statements, such as estimates and statements that describe MJO's future plans, objectives or goals, including words to the effect that MJO or management expects a stated condition or result to occur. Since forward-looking statements address future events and conditions, by their very nature, they involve inherent risks and uncertainties.

Mainstream Minerals Corporation
Neil Sullivan, President & CEO
(204) 222-0137

www.mainstreamminerals.com