Vancouver, British Columbia--(Newsfile Corp. - May 19, 2021) - Riverside Resources Inc. (TSXV: RRI) (OTCQB: RVSDF) (FSE: 5YY) ("Riverside" or the "Company"), is pleased to provide an update on the completed compilation of the spring 2021 technical work at the Cuarentas Project (the "Project"), Sonora, Mexico. Riverside has recovered the Project from Hochschild, who informed Riverside that they will terminate the earn-in option. Riverside still views the Project's discovery potential as excellent with seven untested targets, additional data and improved geologic understanding.

Riverside's President and CEO, John-Mark Staude, stated: "We would like to thank Hochschild for their contributions and collaboration at Cuarentas. We were pleased with the target generation and exploration phase of the option, and with only a modest (1,500 m) program completed there are plenty of compelling targets that remain untested across a Project with historical production history and demonstrated high-grades from surface sampling."

The Cuarentas option agreement lasted for 11 months during which Hochschild spent approximately $1.2M USD, developed broader technical data on target areas and began with drill testing of one of the eight defined target areas. Under the option Hochschild drilled 9 holes (1,500 m) helping outline a better understanding on the past producing Santa Rosalia mine area.

Work executed during the option agreement with Hochschild Mining included:

• Detail mapping.
• Trenching and sampling.
• Soil sampling along Central Rosalia.
• Geophysics, 2.7 km line of inverse polarization (IP).
• Geophysics, reprocessing of the mag data.
• 1,500 m of drilling.
• Structural analysis at surface and using oriented core drilling.

All building strong evidence for 7 additional targets across the entire property, some of which are now ready to drill and other targets warranting some geophysics and further surface work-up exploration (see Figure 1 below).

Figure 1: Map of Los Cuarentas including the 8 targets defined by Riverside. The following A-B cross section in Figure 3 is indicated on this figure.

To view an enhanced version of Figure 1, please visit:
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The 2020-2021 drill program at Los Cuarentas Project targeted the extension at depth of the primary Santa Rosalia historical mine, which was exploited in early 1970's. Results have shown extension with vein parallel faulting cutting the vein at depth, down dropping the remaining target which remains untested (see press release January 11, 2021). Recent data compilation from the Riverside team highlights a well-defined post-mineral break along the Santa Rosalia mine separating the northern altered zone from the southern block which is capped with post-mineral andesite. This area is called the FUZ zone, which is particularly fractured and helps explain the results from January 2021 drilling as shown in a thick blue line in Figure 2 below.

Santa Rosalia target is part of a bigger shear corridor that extends for at least four km and has shown constant high-grade gold at surface including channel sampling up to 3.4 m at 9.1 g/t Au and soil sampling returning up to 0.9 g/t Au (see press release October 8, 2020).

Figure 2: Interpretative map of the Cuarentas Project with large, covered area including the Testerazo trend and specific areas of high-grade gold that will be focuses for next exploration work.

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Field mapping and sampling during the 2020 program by Riverside defined a post-mineral unit covering an extensive steam-heated volcanic unit, potentially preserving a system with parallel structures from the Santa Rosalia Mine (see Figure 3). This system appears to be located in a structurally stable region of the southern block and has caught the attention of Riverside's team, who believes that additional surface exploration is warranted. Historical work from this area by Millrock (2017) reported surface sampling within what appears to be erosional windows with 24.9 g/t Au and 16.5 g/t Au.

This style of epithermal gold system is well known and shows similarities with nearby deposits such as Las Chispas Mine where SilverCrest Metals starting with only a few surface veins has now defined over 30 gold and silver rich veins containing over 0.5M ounces of gold and 49.7Moz of silver¹. At Los Cuarentas, evidence at surface of extensive steam-heated alteration combined with a lithocap to the south and rhyolitic dome to the north, show a direct vector for higher-temperature systems on the property as shown on the cross section below (see Figure 3).

Figure 3: Interpretative cross section-oriented N-S, covering 3 km in length and ~400m vertical of the overall Los Cuarentas Project and highlighting the potential of recent geological discoveries during the Hochschild agreement. This section is interpretative and is not to scale.

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Central Santa Rosalia:

With up to 0.9 g/t Au in soil and 11.5 g/t Au in rock samples, this target makes up the eastern extension of the Santa Rosalia vein along the El Testerazo trend. This is a drill-ready target, which would be volume adding to shallow depth extension of the grade for a first pass.

Santa Rosalia Sur:

Just to the south of Central Rosalia, this target has been one of the primary defined gold-bearing zones with a 200 m long hydrothermal breccia bounded by metric wide stockwork zone with a thickness at surface of up to 3.4 m at 9.1 g/t Au as reported in press release of October 8^th, 2020. Further work on Santa Rosalia Sur will be one of the first priority work areas Riverside can now progress as the geologic and chemical data are suggestive for a high quality target setting. To take advantage of the rig on site, Riverside decided to do one drill hole to define continuity of the described hydrothermal breccia. Assays are still pending for this drill hole, however visuals indicate that the vein zone was intercepted. Additional drilling will be undertaken to better define the strike and depth extension of mineralization.

Southern Extension:

The continuation to the south of Santa Rosalia Sur, the extension is cut from the primary target by a normal fault-oriented E-W and down dropping the southern continuation. Mapping from Riverside's team showed extension of calcite and quartz veining as well as chlorite and clay alteration. This style of lower temperature mineral alteration suggests that the southern extension is higher up in the system

Riverside feels these three areas show good exploration potential and to date demonstrate many similar characteristics to the nearby Mercedes Mine, Santa Gertrudis Mine, Santa Elena Mine all within 50 km and near to this Arizpe mining camp.

Qualified Person & QA/QC:

The scientific and technical data contained in this news release pertaining to the Cuarentas Project was reviewed and approved by Freeman Smith, P.Geo, a non-independent qualified person to Riverside Resources, who is responsible for ensuring that the geologic information provided in this news release is accurate and who acts as a "qualified person" under National Instrument 43-101 Standards of Disclosure for Mineral Projects.

Rock samples from the previous exploration programs discussed above at Cuarentas were taken to the Bureau Veritas Laboratories in Hermosillo, Mexico for fire assaying for gold. The rejects remained with Bureau Veritas in Mexico while the pulps were transported to Bureau Veritas laboratory in Vancouver, BC, Canada for 45 element ICP/ES-MS analysis. A QA/QC program was implemented as part of the sampling procedures for the exploration program. Standard samples were randomly inserted into the sample stream prior to being sent to the laboratory.

About Riverside Resources Inc.:

Riverside is a well-funded exploration company driven by value generation and discovery. The Company has no debt and less than 71M shares outstanding with a strong portfolio of gold-silver and copper assets in North America. Riverside has extensive experience and knowledge operating in Mexico and Canada and leverages its large database to generate a portfolio of prospective mineral properties. In addition to Riverside's own exploration spending, the Company also strives to diversify risk by securing joint-venture and spin-out partnerships to advance multiple assets simultaneously and create more chances for discovery. Riverside has additional properties available for option, with more information available on the Company's website at www.rivres.com.

ON BEHALF OF RIVERSIDE RESOURCES INC.

"John-Mark Staude"

Dr. John-Mark Staude, President & CEO

For additional information contact:

John-Mark Staude
President, CEO
Riverside Resources Inc.
This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: (778) 327-6671
Fax: (778) 327-6675
Web: www.rivres.com

Raffi Elmajian
Corporate Communications
Riverside Resources Inc.
This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: (778) 327-6671
TF: (877) RIV-RES1
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.

¹ Proven and Probable Resources - Technical report and mineral resource estimate for the Las Chispas property, 2019. Las Chispas-MRE-FINAL-14May19.pdf (silvercrestmetals.com)

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