A busy session of exploration results and corporate developments defined the small-cap day, with Great Southern Copper delivering the standout geological news as porphyry-style alteration at Piedras Blancas validated its exploration model and triggered a fresh drill campaign at Artemisa North. Elsewhere, a sharp re-rating at Chill Brands (LSE:CHLL) followed a wholesale platform launch, Orosur Mining (AIM:OMI) extended a gold system with a significant step-out hit, and Avon Technologies (LSE:AVON) fell despite reporting a strong first half, a reminder that strong results can still disappoint a demanding market.
Great Southern Copper confirms porphyry model, drills Artemisa North
Great Southern Copper (AIM:GSCU) rose 6.79% to 2.99p after four scout reverse circulation holes at Piedras Blancas returned pervasive phyllic alteration and potassic overprints consistent with a classic porphyry copper system. The results confirm the geological model the company has been building across its Chilean portfolio and provide the technical basis for advancing the project.
With the Piedras Blancas model validated, Great Southern has now commenced scout RC drilling at the nearby Artemisa North target, extending the programme across what it considers a prospective porphyry corridor. The dual-front progress gave investors a clear catalyst for the day's gain.
Orosur Mining extends Pepas West gold system with step-out drilling
Orosur Mining (AIM:OMI) was among the session's strongest performers, rising 14.06% to 21.9p, after multiple thick, shallow gold intersections at Pepas West suggested a meaningful extension to the known system. The 30-metre step-out hit opens the possibility of a larger resource footprint at the project than previously modelled.
The shallow nature of the mineralisation is a practical positive, reducing the complexity and cost of any future extraction scenario. Orosur characterised the results as potentially indicative of a system extension, and the market responded with the sharpest single-day move among the day's mining names.
Chill Brands launches wholesale platform with 2,000 retailer accounts
Chill Brands Group (AIM:CHLL) surged 65.19% to 0.56p after unveiling Chill Connect, a wholesale distribution platform targeting UK convenience retailers that launched with more than 2,000 accounts already signed. The move marks a deliberate strategic pivot away from a brand-led model toward a distribution-first operation, broadening the company's addressable market considerably.
The scale of the initial retailer base at launch gave the announcement credibility beyond a typical product roll-out, and the share price reaction reflected the significance of the model shift. For a stock trading at fractions of a penny, the move represents a substantial reappraisal of the company's commercial trajectory.
Avon Technologies falls despite strong first-half revenue and margin growth
Avon Technologies (AIM:AVON) dropped 7.1% to 1,492p despite reporting a materially stronger first half, with revenue, profit and margin all rising significantly. Management described the performance as reflecting long-term structural demand in its defence and protection markets, and the company offered no downgrade to its outlook.
The sell-off pointed to a valuation reset rather than any fundamental deterioration, a pattern common in defence-adjacent names that have re-rated sharply on sector tailwinds. The results themselves were unambiguously positive, but the market appeared to have already priced in a strong half.
Marshalls holds full-year guidance as revenue tracks slightly below prior year
Marshalls (AIM:MSLH) edged up 1.03% to 127.1p after confirming that group revenue for the four months to 30 April came in at £205m, running 1% below the prior year but in line with the board's expectations. Full-year guidance was left unchanged, and the update carried no negative revision.
For a building materials business operating in a subdued UK construction environment, a stable trading update with unchanged guidance was enough to attract modest buying. The result confirmed that Marshalls is tracking its internal plan without deterioration.
Arrow Exploration encounters multi-zone pay at Icaco-1
Arrow Exploration (AIM:AXL) gained 7.59% to 23.4p after the Icaco-1 exploration well in Colombia's Tapir Block encountered pay across three separate formations: 30 feet in the Carbonera C7, 15 feet in Gacheta and 26 feet in Ubaque. The company confirmed it is moving to production testing, the next step toward establishing commercial flow rates.
The multi-zone result reduces single-formation risk and raises the potential recoverable volumes from the well. Arrow's ability to test three productive horizons from a single wellbore adds optionality to the Tapir Block programme.
Amaroq reports $18.9m Q1 revenue as Nalunaq ramps
Amaroq (AIM:AMRQ) slipped 2.1% to 101.325p despite reporting first-quarter 2026 revenue of $18.9m from the Nalunaq gold project in Greenland as production continued to build. The company reiterated its full-year 2026 production guidance, signalling confidence in the ramp trajectory.
The modest share price decline suggested the market had anticipated a stronger revenue figure or faster ramp pace, even as the operational narrative remained constructive. Guidance confirmation provided a floor against more significant selling.
Chill Brands aside, East Star Resources adds Endeavour Mining representative to board
East Star Resources (AIM:EST) rose 2.79% to 3.495p after Sonia Scarselli joined its board with immediate effect, representing Endeavour Mining following the larger miner's strategic investment that secured a 14.3% stake in the company. The appointment formalises Endeavour's involvement at board level and adds institutional weight to East Star's governance.
The presence of a major gold producer as a strategic shareholder and now a board participant materially changes the credibility profile of East Star's exploration programme in Central Asia.
Panther Metals completes Winston Tailings assay programme
Panther Metals (AIM:PALM) added 2.86% to 126.0p after releasing the sixth and final batch of Vibracore assay results from the Winston Tailings Project in Australia. The results showed consistent grades across the programme, and the company said the complete dataset would feed directly into a NI 43-101 Mineral Resource estimate and support a recovery-permit application.
Completion of the assay programme is a defined milestone that moves Winston Tailings from exploration-stage sampling toward formal resource definition, a transition that typically attracts a different class of investor attention.
EnergyPathways partners with ABP to assess Port of Barrow for MESH
EnergyPathways (AIM:EPP) gained 2.52% to 11.79p after signing a collaboration agreement with Associated British Ports to jointly evaluate the Port of Barrow as the onshore infrastructure hub for its Marram Energy Storage Hub project. The MESH scheme is designed to repurpose subsea gas infrastructure for energy storage in the East Irish Sea.
Securing a named port partner and a formal evaluation framework advances MESH from concept toward a defined project with physical infrastructure anchors. ABP's involvement brings operational port expertise and a credible counterparty to the development process.
Kelso Group launches £650,000 placing to expand portfolio
Kelso Group Holdings (AIM:KLSO) dipped 1.59% to 3.1p as it announced a placing of new shares representing 5% of issued capital, targeting gross proceeds of approximately £650,000. The funds are earmarked for new additions to its concentrated UK small-to-mid-cap investment portfolio.
The modest dilution and relatively small raise reflected the company's measured approach to portfolio construction. The slight share price softness was consistent with typical placing-day mechanics rather than any adverse read on the investment case.
Thor Explorations returns high-grade shallow hits at Douta
Thor Explorations (AIM:THX) edged up 1.07% to 75.4p after releasing the first 2026 drill results from the Douta Project in Senegal, which included multiple shallow, high-grade oxide intercepts. The company said the results had the potential to support an upgrade to the existing mine plan at Douta.
Shallow oxide mineralisation carries lower processing cost assumptions than deeper sulphide material, and high-grade hits at surface depth are a meaningful positive for any open-pit economics review. The results open a potential resource upgrade pathway ahead of further drilling.
Guardian Metal Resources stakes 193 claims at Tempiute tungsten project
Guardian Metal Resources (AIM:GMR) identified approximately 550 acres of tungsten-enriched historical tailings at its Tempiute project in Nevada and staked 193 new claims, increasing the project's footprint by more than 375%. An auger drilling programme is planned for June to assess the reprocessing potential of the tailings material.
The scale of the footprint expansion and the focus on historical tailings, which carry lower exploration risk than greenfield targets, positions Tempiute as a near-term testable opportunity in a critical mineral that has attracted significant strategic interest globally.
Rome Resources joins DRC airborne survey over Bisie licences
Rome Resources (AIM:RMR) fell 3.9% to 0.37p despite announcing participation in a helicopter-borne geophysical survey covering its two Bisie tin licences in the Democratic Republic of Congo. The survey is designed to calibrate existing anomalies and identify new priority drill targets within the licence area.
Bisie is one of the world's most significant tin districts, and systematic geophysical work is a standard precursor to focused drilling. The share price weakness was not obviously connected to the announcement itself.
Poolbeg Pharma to present POLB 001 cytokine data at EHA Congress
Poolbeg Pharma (AIM:POLB) rose 4.4% to 4.6978p after confirming it will present preclinical data for POLB 001 at the European Hematology Association Congress. The data show the compound reduces key cytokines implicated in Cytokine Release Syndrome while preserving the tumour-killing activity of bispecific antibodies, a clinically important combination of effects.
Presentation at a major haematology congress raises the profile of POLB 001 among the oncology community and provides a formal scientific platform for the CRS programme at a time when bispecific antibody therapies are among the most actively developed drug classes in oncology.
European Green Transition lifts Anemos Analytics stake to 79%
European Green Transition (AIM:EGT) increased its holding in Scotland-based condition-monitoring specialist Anemos Analytics from 52% to 79% for a consideration of £40,000, moving the subsidiary closer to full ownership. Anemos focuses on monitoring technology relevant to wind and renewable energy infrastructure.
The low acquisition cost for a near-27-percentage-point stake increase reflected the early-stage nature of Anemos, but the move consolidates European Green Transition's control over a technology asset directly aligned with its core transition-energy thesis.
Vertu Motors reports profit ahead of prior year in early FY27 trading
Vertu Motors (AIM:VTU) fell 2.29% to 64.0p despite reporting that trading into FY27 had started strongly, with March and April profit running ahead of the prior year. The car dealer's update pointed to resilient consumer demand in its core franchised retail business.
The share price decline despite a positive trading statement suggested the market weighed broader sector concerns or valuation factors above the near-term trading momentum. The update itself contained no negative revision and no guidance reduction.
