Riverside Resources Corporation (TSXV: RRI; OTCCP: Maritime Self-Defense Forces; (FSE: 5YY) reported that a phase two drilling program has begun at the Union project in northwest Sonora, Mexico. This work is carried out by the company working in partnership with Questcorp Mining Company (Private search engine: QQQ), which acquires the project through an option agreement from Riverside.
Program Highlights – Fully Funded Program Underway: A diamond drilling program of approximately 1,500 meters in length across 8 to 10 holes, each averaging 180 metres, is fully funded and requires no dilutive financing in the near term.
Expanding Phase 1 Discoveries: Drilling is designed to expand areas of mineralization, including those intercepted during the Phase 1 program with results announced in January 2026, and to test new areas developed during the winter 2026 field program.
Area-wide target testing: The program tests new targets and explores the surrounding areas of multiple historic mine workings across the 25-square-kilometre La Union project area.
Two Mining Approaches: The holes will test both the deposit-hosted gold mineralization identified in Phase 1 and carbonate-hosted gold-silver-zinc mineralization (CRD), where the gold is associated with mantues, chimneys and structural zones.
Structurally targeted drilling: Angled holes are directed to intersect stratigraphic and structural targets at high angles, as is typical in CRD systems. Structural features interpreted as potential mineralization channels are the main focus of the high-grade gold and zinc programme.
Advanced Target Derisking: Defining the final drill site integrates property-wide structural mapping, 248 kilometers of drone aeromagnetic coverage, and a recently completed property-wide induced polarization (IP) survey.
Geological Analog: The CRD and gold systems that host the deposits at La Union share geological characteristics with large deposits in northern Mexico and the southwestern United States.
Continuous news flow: Exploration is being coordinated with partner Questcorp Mining, to support milestone-based news flow through summer 2026.
Riverside’s exploration work over the past four months has improved understanding of the structural geology and stratigraphy of the project. The union zone lies along the flanks of this range with host strata now studied for target strata that could potentially host significant amounts of gold as found in Paleozoic sedimentary host units in Nevada and likewise in Sonora, Mexico.
Improved mapping and detailed underground sampling have led to a better understanding of the chimney and mantu facets that include structural feeder zones and post-mineral faults.
The targeted focus of exploration is a potentially large gold discovery that expands from previous smaller mine operations on the property. The second phase of drilling aims to test new concepts and expand beyond previous mining sites.
“We are very well positioned to move forward with this second phase of drilling, deploying one or two high-impact holes per target area to evaluate the deep root potential of these deposit-hosted and CRD targets beyond the old legacy mining limits,” said John Mark Studd, CEO of Riverside Resources. “Advanced structural synthesis led by Alejandro Gracida of Riverside has successfully identified major northwest-trending fault structures, which are interpreted to serve as primary structural plumbing and passages for broad areas of high-grade feeder gold mineralization. The comprehensive IP survey completed last week feeds directly into our real-time targeting models, and the program is progressing with rapid operational efficiency.”
“Today marks a transformative milestone for Questcorp as we transition from successful targeted generation to aggressive exploratory drilling,” said Sav Dillon, President and CEO of Questcorp Mining. “Over the past few months, our integrated technical teams along with our partners at Riverside have revealed the true extent of the La Union area. Every layer of new data, from structural mapping to newly completed IP geophysics, points toward a vast, interconnected mineral system that remains largely intact at depth.”
The training program covers more than five target areas. It begins with a follow-up at Union Mine, where prior excavation has resolved key stratigraphic and orientational questions, allowing this tour to venture out into land adjacent to former mining. Underground workings have identified widespread alterations and indications of a mineralized system, making this one of several priority areas. High-quality gold and silver foil channel samples taken underground at Union Mine will now be followed up by drilling.
The second phase of drilling will follow up on the results of the first phase and the broader targets developed through the field exploration program in spring 2026. The second phase will consist of one to three holes per zone, primarily to channel and expand on the first phase drilling. Subsequent drilling is planned after Phase 2 and could be expanded based on results and on geophysics completed over the past few months.
The detailed stratigraphy, lithology and structural framework developed by the Riverside Geological Team specifically target high-grade, favorable prospects for gold mineralization hosted by the deposit and CRD. The five targeted areas outside the Union Mine are as follows:
Al-Ittihad Main Mine – Galis District – The program will use targeted drill holes to test limestone and other carbonate stratigraphic hosts within the Clementi Formation, with access to the underlying Caborca Formation. These units are the primary host of replacement style mineralization and have gold, silver and zinc oxide mineralization in the mine and can be extensive.
North Union Mine – Nigra Region The initial focus of the program will be on testing structural explanations for northwestern fault feeding zones. The New Nigra area has provided gold mineralization in the samples and could now be a new, previously untested drilling area.
Lewis Hill – Alig Hill area – The upper part of the Clementi Formation revealed deposits containing gold in the first phase of drilling, allowing follow-up work to expand on this. The geology team has carefully mapped the stratigraphy and structural geology northward for more than two kilometers and this target could have huge potential. The precise structural mapping has found some important cross-linking structures which the team will now target during this phase.
Bridge mine area -The Clementi Formation is the primary host unit, and structural features combined with former mining areas provide multiple target areas that can now be pursued beyond the first phase of drilling. The precise 1:1000 mapping conducted by Gracida across the northwest features, combined with detailed alterations mapping, gives Questcorp the best chances of success with its investment through Riverside in this work.
Jabali area – The main targets are the northwest strike structural veins, where the strike length has so far been determined to be 200 meters and a surface width of 30 meters across a series of low-sulfur refractory quartz veins. High quality assays exceeding 5 g/t Au have been returned from this area. During this phase, drilling at Jebali will focus on two holes: one to test the target vein and the other to test the source target. Detailed maps and cross sections of each target were prepared prior to drilling to better define the conceptual targets.
The project is summarized in the NI 43-101 Technical Report that was recently published and, more succinctly, on the Riverside website. Riverside initially acquired the project and subsequently consolidated additional mineral claims to build a strong land position. The company then developed the project through surface access agreements and drilling permits, making it a ready-made exploration opportunity for Optionee.
The project was originally identified through Riverside’s exploration work in the western Sonora gold belt, conducted in collaboration with AngloGold Ashanti Limited, Centra Gold Inc. and Hochschild Mining Plc. Previous doctoral research by Riverside founder John Mark Studd has also contributed to recognizing the potential of the area. Initial work by Riverside team members, drawing on more than two decades of geological collection and analysis, has confirmed that the area has a very promising future.
In the project, Penoles’ historic mining targeted chimney- and manto-style replacement bodies within the upper oxide zones. As a result, the underlying sulphide zones represent immediate drilling targets for further exploration.
The project features favorable limestone host rocks, an extensive alteration footprint, and multiple small-scale historic workings, with mineralization patterns similar to those found at the Hermosa Project in southern Arizona. In Hermosa, South32 is developing mines after acquiring the project from Arizona Mining for more than $400 million, and Hermosa is now considered one of the most promising upcoming mining operations in Arizona.
At La Union, direct drill targets offer the potential for large-scale discoveries. The project is well positioned to deliver near-term exploration results, with targets including deeper oxide and sulphide mineralization.
Riverside is a well-funded exploration company driven by value generation and discovery. The company has a strong balance sheet with no debt and 93 million shares outstanding with a strong portfolio of gold, silver, copper and revenue assets in North America. Riverside has properties available for option.
