Unity narrows search for gold source at Rohav Mountain
Unity Metals has added a key piece to the geological picture at Rohav Mountain gold discovery in Cambodia, with geophysics identifying what it believes could be the source of the mineralising system and providing a new set of drill targets.
Locating the source
Unity (ASX:UM1) has been building its understanding of Rohav Mountain since making the discovery during maiden drilling at its Ngot project earlier this year. That drilling established a substantial gold-bearing system, returning 23m at 0.9g/t Au from 120m and a high-grade hit of 1m at 7.9g/t Au within a highly altered diorite intrusion more than 150m wide.
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Detailed geophysics has now given the company a clearer picture of what could be happening beneath Rohav Mountain. Magnetic modelling has identified a sizeable interpreted magnetite-bearing intrusion beneath the mountain and largely north of the initial drilling. Unity believes this deeper intrusion could be the source of the hydrothermal fluids that altered the earlier diorite and the source of the Rohav Mountain mineralisation. In simple terms, Unity may finally have located the source of the Rohav Mountain gold system and is set to drill it for the first time.
The new LiDAR survey also provides detailed topographic data to an accuracy of less than 5cm, helping Unity model the geology and mineralised zones in 3D and position drill holes across Rohav Mountain’s steep terrain. Magnetic anomalies extend strongly at depth and Unity’s existing drill holes sit above the interpreted intrusion and have not directly tested it. This creates a significant gap in the data, as the company cannot confirm the exact nature of the deep structures without intersecting them.
New targets emerge
Unity’s dipole-dipole induced polarisation survey identified a series of discrete, finger-like chargeability and resistivity anomalies around the margins of the interpreted intrusion. The company believes these could represent sulphide-rich, strongly silicified zones, potentially including quartz veins associated with epithermal gold mineralisation. The eastern and northern margins are of particular interest, with Unity believing those areas could preserve zones of intact mineralisation. Later-stage epithermal veins have already shown they can carry strong gold grades at Rohav Mountain. The strongest gold encountered in drilling is associated with these later veins, while surface sampling of exposed mineralisation has returned up to 24.7g/t Au and 206g/t silver, along with 0.9% lead and 4.4% zinc.
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Gold clues downstream
Mineralisation discovered in the altered diorite at Rohav Mountain lies about 400m directly upstream from alluvial artisanal workings, where miners are recovering angular gold nuggets from alluvium, or loose cover, to depths of just 2m. The location of those workings and the angular nature of the gold being recovered are useful clues as Unity works to understand the source and distribution of gold across Rohav Mountain. The creek exposing primary mineralisation drains west towards the most extensive artisanal alluvial gold workings within the entire Ngot project area.
Founder and managing director Craig Mackay said the company believed it may have identified the potential “engine room” responsible for the intense hydrothermal alteration and a source for the gold mineralisation discovered at Rohav Mountain. Around the margins of the interpreted intrusion, the DDIP survey has identified anomalies that Unity believes may represent intact zones of gold-bearing epithermal veins. The first drilling made the Rohav Mountain gold discovery. The next campaign is set to test Unity’s evolving understanding of what may be driving that system and where some of its most prospective gold mineralisation could be sitting.
