June 30, 2011 – Vancouver, BC: Riverside Resources Inc. ("Riverside") (TSX-V: RRI) and Guerrero Exploration Inc. (“Guerrero”) (TSX-V: GEX) are pleased to announce the signing of a definitive option agreement (the “Agreement”) for the Chapalota Project in Sinaloa, Mexico. In order to acquire a 60% interest and exercise the initial option Guerrero must issue Riverside an aggregate 1,250,000 Guerrero shares, make total cash payments of $200,000 to Riverside, and incur an aggregate $4,000,000 in exploration expenditures on the Chapalota Project within 36 months of the Agreement.

David Stadnyk, President and CEO of Guerrero Exploration Inc., stated “We are very pleased to sign the definitive option agreement with Riverside. The drilling program at the Leona Target is progressing very well and additional holes are now underway. Guerrero will continue to follow the progression of the drilling results with great anticipation”.
John-Mark Staude, President and CEO of Riverside Resources Inc., added “Core drilling is an exciting step for the Leona Target at the Chapalota project. The surface gold assays combined with IP conductivity and resistivity at the Leona target makes this one of five primary target areas on the 90 square kilometer property. Previous small scale mining in the region is an indication that mineralization may be found at depth.”

Riverside and Guerrero commenced an anticipated 2,000m core drilling program earlier this month with the aim of drill-testing several geochemical and geophysical anomalies that were generated from a multi-stage generative exploration program. The geochemical anomaly discovered through soil and rock chip sampling defined a broad target area of 5 kilometers by 3 kilometers. Recent exploration work included 31.5 line kilometers of Induced Polarity-Resistivity geophysics, which shows a coincident anomaly that is now being drilled.

The first drill hole has now been completed and crossed the intrusive contact and picked up sulphide, chlorite, and quartz veining. The hole had an upper zone of granodiorite porphyry diking and silicified breccia with disseminated arsenopyrite and quartz veining. The second drill hole at the Leona target is now underway and again finding sulphides with dikes and metamorphic rocks.

Trench samples have been sent to the laboratory and results are anticipated to be released during July, meanwhile drill core from the first drill hole is being logged, split, and sampled. The drill program at Chapalota is scheduled to complete eight to ten holes. Each hole is planned to range from 200 to 250 meters in depth and with many at a 50 degree angle the true depth will be roughly 160 meters and well within open pit target depth.

Additional Agreement Terms:

Upon the exercise of the Initial Option, Riverside will grant Guerrero an irrevocable option to acquire an additional 10% interest in the Chapalota Property (the “Additional Option”). Guerrero can exercise the Additional Option by paying Riverside $500,000 and incurring an additional $1,500,000 in exploration expenditures on the Chapalota Property on or before the date that is 12 months from the Initial Option Exercise Date. Upon the exercise of the Initial Option, provided that Guerrero surrenders its right to the Additional Option, Riverside and Guerrero shall be deemed to have formed a joint venture (the “Joint Venture”) with both company’s holding 40% and 60% interest respectively.

Assaying and Qualified Person:

The scientific and technical data contained in this news release were prepared under the supervision of Mark J Pryor, Pr.Sci.Nat., an independent qualified person to Riverside Resources, who is responsible for ensuring that the geologic information provided in this news release is accurate and acts as a "qualified person" under National Instrument 43-101 Standards of Disclosure for Mineral Projects.

Samples were taken to Hermosillo, Mexico where ALS Laboratory Group’s mineral division ALS Chemex crushed and pulverized each sample. The rejects remained with ALS Chemex while the pulps were transported to ALS Chemex’s ISO 9001-2008 certified laboratory in North Vancouver, BC, Canada for analysis. A QA/QC program was implemented as part of the sampling procedures for the exploration program. Duplicate, standard and blank samples were randomly inserted into the sample stream prior to being sent to the laboratory.

About Riverside Resources Inc.:

Riverside is a well-funded prospect generation team of focused, proactive gold discoverers with the breadth of knowledge to dig much deeper. The Company currently has approximately $10,000,000 in the treasury and fewer than 35,000,000 shares issued. Riverside`s model of growth through partnerships and exploration looks to use the prospect generation business approach to own resources, while partners share in de-risking projects on route to discovery. Additional property information on the Company’s projects can be found on the Riverside Resources Inc. website at www.rivres.com.

About Guerrero Exploration Inc.:

Guerrero Exploration Inc. is committed to a long term business strategy designed to achieve optimal levels of profitability and shareholder value. Guerrero Exploration Inc. is a Canadian based exploration mining company with a focus on the high yielding Mexican copper, gold and silver mining area known as the Southern Mexican Gold Belt and the Sierra Madre Occidental Belt. The Corporation’s common shares trade on the TSX Venture Exchange under the symbol “GEX”.


"John-Mark Staude"

Dr. John-Mark Staude, President & CEO

For additional information contact:

Joness Lang

Manager, Corporate Development
Riverside Resources Inc.
Phone: (778) 327-6671
Fax: (778) 327-6675
Web: www.rivres.com

Kaley Reid

Corporate Communications
Riverside Resources Inc.
Phone: (778) 327-6671
Fax: (778) 327-6675
Web: www.rivres.com

Certain statements in this press release may be considered forward-looking information. These statements can be identified by the use of forward looking terminology (e.g., "expect”,” estimates", "intends", "anticipates", "believes", "plans"). Such information involves known and unknown risks -- including the availability of funds, the results of financing and exploration activities, the interpretation of exploration results and other geological data, or unanticipated costs and expenses and other risks identified by Riverside in its public securities filings that may cause actual events to differ materially from current expectations. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

Neither the 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.