Arc Minerals (LSE:ARCM) dipped 2.3pc to 3.2p today despite reporting higher-than-expected cobalt grades in the latest round of drilling at its flagship Zamsort project in Zambia. The business drilled numerous short holes at the oxide portion of Zamsort’s Kalaba cobalt-copper prospect to confirm the grade of material intended for processing at its commercial-scale demonstration plant (CSD plant).
The work intersected cobalt grades averaging over 0.2pc and up to 0.35pc over mineable widths alongside copper grades up to 1.5pc. Arc added that the mineralisation is hosted in a saprolitic horizon with a low strip ratio to access the near-surface ore. This means it can be mined without the need for drilling and blasting, keeping down costs.
Kalaba’s licence covers nine of 30 high priority targets ranked by a previous JV in the area operated by Anglo American and is near First Quantum’s Sentinel and Kansanshi and Barrick’s Lumwana mines. The project has an existing near-surface estimated copper-cobalt oxide resource of 16.59Mt at 0.94pc copper and a historical exploration target of 150Mt, making it one of the most significant projects of its type in Zambia.
Elsewhere, the firm said that commissioning of the CSD plant is on track for next month. As a result of the strong presence of cobalt, the plant is currently undergoing tests to ensure it can maximise cobalt recovery and process a separate cobalt and copper concentrates. Arc said it is testing two cost-efficient systems with encouraging early results, adding that it will provide a further update once it has decided on the route going forward for the plant. The company’s executive chairman Nick von Schirnding said:
‘These results are very encouraging, in particular the high-grade cobalt mineralisation intersected in this round of drilling. These results from the pit areas immediately adjacent to the CSD plant show mineralisation that is near surface and hosted in weathered material that can be mined without the need to drill and blast, which should provide for low strip ratios and correspondingly very low mining costs. As a result of higher than expected Cobalt grades encountered, Kalaba is becoming a cobalt project along with copper and as such work is underway to maximise the cobalt recoveries to ensure that full value is extracted.’
He added that the business is looking forward to providing further drilling results as well as the results of its recently-completed Airborne Geophysical programme at Zamsort. The 1,000km2 survey was carried out to highlight further geological structures associated with known zones, potential new zones of mineralisation and to prioritise areas for additional drilling.
Arc also owns a 100pc interest in Casa Mining, a private company that has a 71.25pc stake in the Akyanga gold deposit in the DRC. At the end of July, the business rose 12.5pc after reporting that a JORC mineral resource for Akyanga had almost doubled to 3m ounces of gold averaging 2.16 grams per tonne.