Mainstream Minerals Corporation; Update on the recent work completed on its portfolio of properties

July 13th, 2010 - Winnipeg, MB - Mainstream Minerals Corporation (TSX-V: MJO) ("Mainstream Minerals") is pleased to report on the exploration and development work that has either been recently completed or is presently ongoing on its portfolio of properties located in the Red Lake and West Timmins Gold Camps of Ontario.

Bobjo Mine Project, in Earngey and Agnew Townships of the Red Lake Mining Division of Ontario

With the execution of the Property Interests Exchange Agreement with King's Bay Gold Corporation on June 14th, 2010 (see the news release of June 16th, 2010 for details on this agreement), Mainstream Minerals now has an undisputed 100% ownership interest in the Bobjo Mine Project's land package of 9 patented and 218 unpatented claim units. The exploration program that was previously announced on February 11th, 2010 for the Bobjo Mine Project was limited due to ongoing talks with a third party for a potential transaction on another property within the area. The Company is presently in discussions with a number of geological contractors in regards to putting together a $750,000 work program. The Company expects to re-start its exploration program in the next few weeks. Michael Romanik, President & CEO, stated that "We are very excited to get back to work on the Bobjo Mine Project and we would like to take this opportunity to thank our shareholders for their patience and understanding while we were quietly putting together a deal over the past several weeks to acquire 100% ownership of this promising project".

Hazard Lake / Northgate Deposit Property in Uchi Lake Township, Red Lake Mining Division of Ontario

In a news release dated January 25th, 2010, the Company was pleased to announce that it had engaged the services of Mr. A.A. Burgoyne, P.Eng., M.Sc. of Burgoyne Geological Inc. as the Qualified Person (QP) for the purposes of completing a detailed Technical Evaluation Report on the historical exploration work carried out on this recently acquired gold property. Mr. Burgoyne delivered his report and made a number of specific recommendations for a Phase I exploration and development program on this property. The Company is reviewing these recommendations as part of the first step in the plan to move ahead with further work that may eventually establish a National Instrument 43-101 resource on the property.

Price Claims Property in Price and Adams Townships, Porcupine Mining Division of Ontario (West Timmins area)

In February, the Company engaged the services of Vision Exploration. On this 134 claim unit property, Vision Exploration completed 57.4 kilometres of line cutting, 24.5 kilometres of Induced Polarization Survey, and 57.4 kilometres of Magnetometer Survey. As of the date of this news release, and for the fiscal 2010 year to date, a total of $88,585 has been spent for work performed on this Price Claims Property. The data is currently being interpreted by the Company's contracted geophysicist based out of Timmins, ON.

West Keefer Claims Properties in Keefer Township, Porcupine Mining Division of Ontario (West Timmins area)

The Company engaged the services of Vision Exploration in February for preliminary exploration and development work to be completed on these properties. On the northern block of 26 claim units, Vision Exploration completed 14.7 kilometres of line cutting, 11.5 kilometres of Induced Polarization Survey, and 14.1 kilometres of Magnetometer Survey. On the southern block of 8 claim units, Vision Exploration completed 13.1 kilometres of line cutting, 11.2 kilometres of Induced Polarization Survey, and 13.1 kilometres of Magnetometer Survey. As of the date of this news release, and for the fiscal 2010 year to date, a total of $62,810 has been spent for work performed on these West Keefer Claims Properties. The data from the surveys is being interpreted and future work programs on the West Timmins projects will be based off the recommendations in the reports.

About Mainstream Minerals

Mainstream Minerals Corporation is a mineral exploration and development company focused on precious metals mining properties with economic potential, with the aim of bringing such properties to commercial production. The Bobjo Mine and the Hazard Lake / Northgate Deposit projects are located in the prolific Red Lake Gold Camp in Ontario. Other projects include the Price and West Keefer Claims located in the West Timmins area.

MJO Shares Outstanding: 38,451,021

ON BEHALF OF THE BOARD

Signed "Michael Romanik"

Michael Romanik, President & CEO

(204) 222-0137

info@mainstreamminerals.com

www.mainstreamminerals.com

This news release includes certain forward-looking statements concerning the future performance of Mainstream Mineral Corporation's business, its operations and its financial performance and condition, as well as management's objectives, strategies, beliefs and intentions. The Company does not intend, and does not assume any obligation, to update these forward-looking statements. Forward-looking statements are frequently identified by such words as "may", "plan", "expect", "anticipate", "estimate", "intend" and similar words referring to future events and results. These forward-looking statements represent management's best judgment based on current facts and assumptions that management considers reasonable. The Company makes no representation that reasonable business people in possession of the same information would reach the same conclusions. All forward-looking information is inherently uncertain and subject to a variety of assumptions, risks and uncertainties, including the speculative nature of mineral exploration and development, fluctuating commodity prices, competitive risks and the availability of financing and as described in more detail in the Company's recent securities filings available at www.sedar.com. Actual events or results may differ materially from those projected in the forward looking-statements and readers are cautioned against placing undue reliance thereon.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.