Lion Rock Resources IncTSXV: ROAR

Mainstream Minerals acquires 100% control of the Bobjo Mine Project in the Red Lake Gold Camp of Ontario

· Issued by Lion Rock Resources Inc

Jun. 16, 2010 (TheNewswire.ca) --

Winnipeg, MB - Mainstream Minerals (OOTC:MSMCF) (TSXV:MJO) Corporation (TSX-V: MJO)("Mainstream Minerals") is pleased to report that it has come to an agreement with King's Bay Gold Corporation (TSXV:KBG) ("King's Bay Gold") on the future of their joint-ventured Bobjo Mine Project, located in Earngey and Agnew Townships of the Red Lake Mining Division of Ontario.

In a Property Interests Exchange Agreement dated June 14th, 2010, King's Bay Gold has sold its' remaining interests of approximately 40% in the Bobjo Mine Project to Mainstream Minerals. King's Bay Gold has further agreed to cancel the advance receivable related to the project of approximately $140,000 from Mainstream Minerals to King's Bay Gold.

In consideration for Property Interests Exchange Agreement of June 14th, 2010, Mainstream Minerals has agreed to:

(a) assign to King's Bay Gold it's one hundred per cent (100%) interest in the Raleigh Lake property.;

(b) grant 250,000 common shares of Mainstream Minerals to King's Bay Gold;

and

(c) transfer title of ownership on various pieces of equipment valued at approximately $16,000.

Both Parties further agreed to waive any and all present and future claims whatsoever against one another in relation to the Bobjo Mine Project Joint Venture Earn-In Agreement of September 12th, 2006, including all amendments entered into thereafter, and to save the other party harmless from any and all present and future third party claims whatsoever as these may relate to the Bobjo Mine Project.

With the execution of the Property Interests Exchange 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 for approximately 9,080 acres. The common shares being issued shall be subject to the approval of and the hold periods as required by the applicable policies of the TSX Venture Exchange Inc. The Agreement itself is also subject to the approval of the TSX Venture Exchange Inc.

Mainstream President & CEO, Michael Romanik said "We are exceptionally pleased to have been able to secure 100% ownership of the Bobjo Mine Project. With our adjoining 100% owned Hazard Lake / Northgate Deposit property, we now have a fantastic land package to focus our exploration efforts on. 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 Bobjo Mine property is located approximately 80 kilometres by road northeast of the town of Ear Falls, Ont. The historic Bobjo Mine operated for two years and saw limited production from a small underground mining operation. A figure of 362 ounces of gold was reported from an unknown tonnage in the Ontario Department of Mines annual reports for 1929. On the adjacent property to the east, the Uchi Lake Mine had considerably more success with a similar-hosted quartz-vein-type deposit operated from 1939 to 1943. It produced 757,074 tons grading 0.151 ounce per ton (114,467 ounces). In total there are at least five past-producing gold mining operations within a 12-kilometre radius of the Bobjo Mine Project as well as numerous gold occurrences that are documented in the geological reports and government publications.

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 Project is located in the prolific Red Lake Gold Camp in Ontario. Other projects include the Hazard Lake / Northgate Deposit, Price Claims and West Keefer Claims.

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.

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