Exploration news dominated the mining sector today, with a London-listed Africa-focused explorer unveiling fresh copper discoveries in Morocco even as its shares slipped, while Rio Tinto held firm on full-year guidance on the back of a standout quarter at Oyu Tolgoi. Elsewhere, weather proved the great leveller: Thor Explorations was forced to cut its gold output guidance after rains battered its Nigerian mine, while Orosur Mining pressed ahead with a promising but mechanically troubled drill campaign in Colombia.
Aterian expands copper footprint at Morocco's Azrar
Aterian (LSE:ATN) said initial fieldwork at its 85%-owned Azrar copper-silver project in Morocco has identified multiple copper showings and substantially expanded the known mineralisation footprint at the Amane target, even as its shares eased 2.08% to 23.5p. The London-listed Africa-focused critical metals explorer and trader framed the discovery as early validation of a broader strategy: funding exploration not through dilutive equity raises but through a joint venture with Lithosquare SAS, the Paris-based geological analytics firm that is bankrolling Aterian's 2026 work programme in exchange for a growing equity stake in the underlying assets.
Mapping of just 4 of the 22 planned traverses at Amane has already identified copper showings across an apparent 1.60km strike length within what is now a 2.50km long target, with new stratabound copper showings reaching apparent thicknesses of up to roughly 7m at Amane West and 2m at Amane North. Historic workings tied to visible copper mineralisation have also turned up at the site, which sits in Morocco's Western Anti-Atlas roughly 45km east of Managem Group's Tizert copper-silver project. At the Tifrit target, previously undiscovered stratabound copper mineralisation has also been identified within basal conglomerate and sandstone beds, traced laterally over 50m with apparent widths of 3m. The Lithosquare arrangement, completed in June, commits the French firm to invest €1m to fully fund Aterian's work across nine projects spanning Morocco and Botswana, earning an initial 15% participating interest and a 0.5% net smelter return with scope to increase both through milestones.
"The initial mapping results strengthen Azrar's exploration potential by expanding the known copper mineralisation footprint at Amane and identifying multiple copper showings, including in previously unexplored areas," said Charles Bray, executive chairman of Aterian.
With only a fifth of the planned traverses mapped so far, the scale of what remains to be tested at Amane and Tifrit is the real takeaway, Aterian is still at the earliest stage of defining Azrar's extent, and Bray himself cautioned that continuity and full extent of mineralisation remain to be determined. The funded-exploration model is arguably as significant as the geology: by having Lithosquare underwrite the drilling campaign across a nine-project portfolio, Aterian preserves its balance sheet and avoids shareholder dilution while generating the kind of newsflow that can re-rate a junior explorer, provided follow-up drilling confirms what surface mapping has only begun to sketch out.
Rio Tinto holds guidance as Oyu Tolgoi and Simandou drive momentum
Rio Tinto (LSE:RIO) told investors that global iron ore sales rose 3% year-to-date to 255.3m tonnes for the nine months to 30 September, as the miner maintained full-year production and sales guidance across iron ore, copper, aluminium and lithium despite shares dipping 1.215% to 6,912p. Copper-equivalent production rose approximately 1% year-to-date, with the real story at Oyu Tolgoi in Mongolia, where copper production climbed 27% year-on-year in the third quarter and 29% year-to-date, the operation running at an annualised rate of roughly 450,000 tonnes in the quarter.
Total consolidated copper output was flat year-on-year in the quarter at 205,000 tonnes, held back by a flash converting furnace rebuild at Kennecott following a breach in late June, a repair Rio Tinto said it completed roughly 70 days later, at the end of August, ahead of schedule. Simandou, the Guinea iron ore project in which Rio Tinto's SimFer joint venture holds an 85% stake alongside the Government of Guinea, reached an annualised production milestone, underscoring the project's transition from construction to ramp-up.
Holding guidance steady while absorbing an unplanned furnace outage at Kennecott signals operational resilience rather than complacency, and the Oyu Tolgoi ramp-up in particular reinforces the investment case for Rio's underground expansion strategy in copper, a metal the group has repeatedly flagged as central to its long-term growth. With Simandou now contributing to volumes, the diversification away from a pure iron ore dependency is becoming visible in the operational numbers rather than just the strategy slides.
Thor Explorations cuts full-year gold output guidance after heavy rain hits Segilola
Thor Explorations (AIM:THX) cut its full-year 2026 gold production guidance to a range of 70,000 to 72,000 ounces, down from 75,000 to 85,000 ounces, after heavy rains in late August disrupted mining operations at its Segilola mine in Nigeria, sending shares down 9.244% to 54p. The gold producer, which also develops the Douta Gold Project in Senegal, poured 15,515 ounces in the third quarter and sold 19,000 ounces at an average realised price of $4,297, generating quarterly revenue of $81.7m, while keeping full-year all-in sustaining cost guidance unchanged at $1,000 to $1,200 per ounce.
Segilola's process plant still recovered 92.8% of gold from 249,607 tonnes milled at an average grade of 2.10 grammes per tonne, but total mined material fell sharply to 567,059 tonnes for the quarter, down from 1.13m tonnes in the second quarter, a clear marker of how severely the rainfall curtailed mining activity. "We are pleased to report another solid quarter for Thor, despite the challenging operating conditions experienced at Segilola as a result of exceptionally heavy rainfall during the period, demonstrated considerable resilience in navigating these challenges," said Segun Lawson, president of Thor.
The guidance cut is a meaningful downgrade in percentage terms, trimming the top end of the range by roughly 15%, yet the unchanged cost guidance suggests the disruption was a volume problem rather than a cost-inflation one. With gold prices realised above $4,200 an ounce, the revenue hit from lower output is partially cushioned by price strength, but investors will want assurance that the rainfall impact is a one-off weather event rather than a sign of deeper operational vulnerability at Segilola heading into the wet season next year.
Orosur says gold hole open at depth, Pepas permitting advances
Orosur Mining (AIM:OMI) said its first drill hole at the El Cedro prospect in Colombia, CED001, continues to show consistent gold mineralisation from surface and remains open at depth, though shares fell 6.78% to 13.75p on the day. The TSX Venture and AIM-listed explorer returned a composite intersection of 267.4m at 0.65g/t gold from surface, including higher-grade sections of 46.4m at 1g/t from 19.2m, 28.25m at 1.01g/t from 118m, 22.2m at 1.01g/t from 225m and 2.15m at 3.89g/t from 232m, at the El Cedro gold-copper porphyry cluster within Orosur's Anzá project in the Mid-Cauca gold belt west of Medellín.
The hole was originally designed to reach 500m but was prematurely terminated at 267m due to drill rig operational issues. Orosur has since discussed the problems with its drilling contractor and positioned a new hole, CED001A, alongside the original to complete the intended depth coverage. "These developments mark a real step forward, adding to our momentum. With temporary drilling issues resolved, CED001 continues to deliver, providing evidence of a mineral system of substantial scale," said Brad George, chief executive of Orosur.
El Cedro was first identified through Anglo American reconnaissance work before Orosur began its first-ever drilling campaign there in August, and the consistency of mineralisation from surface across a near-270m intercept is an encouraging sign for a target still in its opening phase of testing. The rig issues that truncated CED001 are a mechanical setback rather than a geological one, and the swift deployment of CED001A alongside the original hole suggests management is keen to re-establish depth continuity data before the market loses patience with delays.
