CSAMT Geophysics at the Last Chance Gold Target Alaska
The CSAMT geophysics survey was conducted by Zonge International, Inc., one of the world's leading geophysical contractors. CSAMT surveys provide resistivity information that relates to structure, lithology and permeability of the sub-surface rocks.
These initial four lines of CSAMT were surveyed to map the variability of rock resistivity across the core area of the large Last Chance gold target, to identify rock resistivity characteristics that could assist in interpreting the upper levels of the gold system and determine whether resistivity could be useful in targeting structure and alteration associated with mineralisation. The CSAMT method can be used to identify targets at shallow levels where surface talus conceals the underlying geology, and also be used at depth where geological observations from reconnaissance mapping and drilling, and surface geochemical results suggest that the Last Chance gold target lies within the upper brittle domain of a large orogenic and/or IRGS (Intrusive Related Gold System).
The four lines of CSAMT totalled nine line kms, oriented in a northeast-southwest direction over the core area of strong gold-arsenic soil anomalism (Figure 1*) and associated hydrothermal silica breccia bodies identified from surface reconnaissance (Figure 2 & 3*). The CSAMT survey clearly identifies the mapped carbonaceous schist as a low resistivity (conductive) lithological unit along the northern margin of the main gold-arsenic anomaly. Localised hydrothermal silica breccia bodies mapped at surface and intersected in drilling, such as at the Pickle prospect, correspond with more resistive zones modelled from the CSAMT data (Figure 4*). Elsewhere, the modelled CSAMT data shows significant resistivity variation that is likely to relate to a combination of structure and alteration given the generally uniform quartz-mica schist country rock across the target area (Figure 5*).
The CSAMT resistivity survey will form an important data set alongside the other data collected during the Company's very first 2020 field season at Last Chance. Together, the CSAMT resistivity data will be integrated with the airborne magnetic and radiometric data, the satellite multispectral data, reconnaissance geological mapping, detailed surface geochemistry and data from drill core including detailed geology, structure and multi-element geochemistry. Once integrated, these quality datasets will be used to generate a 3D model of the geology, rock alteration and structure and provide White Rock with a quality interpretation of this overall gold system, its regional setting and a range of follow-up targets for the 2021 field season.
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About White Rock Minerals Ltd
White Rock Minerals Ltd (ASX:WRM) is a diversified explorer and near-stage producer, headquartered in Ballarat, Victoria. The Company's flagship exploration project is Red Mountain in central Alaska. At Red Mountain, there are already two high grade zinc - silver - gold - lead VMS deposits, with an Inferred Mineral Resource of 9.1 million tonnes @ 12.9% ZnEq for 1.1 million tonnes of contained zinc equivalent. The Company is also exploring its recently discovered large intrusion related gold anomaly at Last Chance, also located in the Tintina gold belt of Alaska, home to multi-million gold ounce deposits like Pogo, Fort Knox and the Donlin Project. The Company also has the Mt Carrington project, located near Drake, in Northern NSW, which is a near-production precious metals asset with a resource of 341,000 ounces of gold and 23.2 million ounces of silver on an approved mining lease, and with a Gold First PFS and JORC Reserve. White Rock Minerals is listed on the Australian Stock Exchange.
White Rock Minerals Ltd