NT Minerals (ASX:NTM) reports final assays for the 2022 field season drilling have been received at the Redbank Copper Project, located in the southeastern McArthur Basin in the Northern Territory.
The assays are from 22 reverse circulation (RC) holes completed for 5,008m across 3 target areas including Calvert South, VTEM Anomaly and Prince.
At Calvert South, the company drilled 10 holes for 2,010m over multielement soil anomalism at Calvert South.
The company drilled 11 holes at VTEM Anomaly for 2,782m over discrete conductive and chargeable targets of the regional VTEM anomaly identified in late 2021.
At Prince, NT Minerals drilled 1 hole for 216m over a chargeable anomaly with no associated conductivity.
“We are also pleased that drill results at Calvert South validate the anomalous regional soil results collected in 2021 and 2022″
NT Minerals Managing Director Hugh Thomas said the company is encouraged to further their search into the lower stratigraphic reductant units in the project.
“We are also pleased that drill results at Calvert South validate the anomalous regional soil results collected in 2021 and 2022.
“Early drilling content at Calvert South suggests further follow-up drilling is warranted on the basis of understanding the drilling contacts encountered and determining the possible extent of the system.
“We look forward to expanding on the early-stage exploratory drilling as well as providing further updates from yet to be received soil sampling results over this poorly explored and overlooked district.”.
NT Minerals reports first pass reconnaissance drilling at Calvert South this year has validated soil geochemistry, identifying anomalous horizons of ‘low-level’ copper mineralisation up to 0.93% Cu (22CT03) that needs further systematic investigation to understand extent and emplacement.
It says encouraging visual copper mineralisation has been identified in carbonate and dolomitic chip samples during the drilling campaign that have been validated with geochemical analyses.
Near surface anomalism is present in numerous holes including 5m @ 0.32% Cu from 7m to 12m in 22CT03, 19m @ 0.16% Cu from surface to 19m in 22CT04, and 5m @ 0.12% Cu from 14m to 19m in 22CT09.
NT Minerals also reports in focused drilling at Calvert South, there is evidence of ‘thin’, anomalous stratiform copper mineralisation dipping gently east over at least 1.2km, and recorded intervals include 1m @ 0.33% Cu from 107m in 22CT03, 3m @ 0.38% Cu from 116m to 119m in 22CT05 and 7m @ 0.26% Cu from 131m to 138m in 22CT010 remaining open to the east.
The company will conduct further work to better understand prospective stratigraphy while seeking a mineralising fluid pathway to explain copper mineralisation in permissive and reductant horizons.
At VTEM Anomaly, NT Minerals identified a 5km by 5km regional conductor target located around 7.5km east-northeast of Redbank from a VTEM-max survey that was subsequently strengthened by group IP surveying in late 2021.
The company interprets that copper-bearing fluids have hydraulically migrated from the linear Redbank structural corridor to precipitate in receptive reductant horizons like the shales of the Wollogorang Formation.
Historically, this large conductive target has only been tested on its margin by a single deep diamond hole by Gulf Mines in 2008, and this work visually recognised minor occurrences of copper-bearing sulphides, chalcopyrite and bornite.
First pass reconnaissance drilling completed by NT Minerals over this target in 2022 has identified independently anomalous, single metre intervals of up to 0.35% Cu in 22VT04 and 1.17% Zn in 22VT10.
The company reports week copper anomalism is consistently observed near the upper Settlement Creek Dolerite contact, which is known to be a flat-lying intrusive sill capable of providing a potential fluid pathway for metal brines to gain access to the receptive carbonate horizons of the Wollogorang Formation.
NT Minerals also notes zinc anomalism is present in the Lower Wollogorang Formation shale horizons, and drilling of chargeability and conductivity anomalies has identified both anomalous geological contacts of the Settlement Creek Dolerite and carbonaceous shales of the Wollogorang Formation.
Although anomalous copper values are evident, initial drilling over this regional target has not located evidence for a large-scale structural fluid conduit for mineralising brines.
Early-stage drilling has downgraded this target as being a large mineralising system.
The company’s hypothesis for copper mineralisation remains valid, and attention will include locations testing the McDermott Formation, considered to be the first reductant, located lower in the prospective Tawallah Group stratigraphy.
At Prince, NT Minerals drilled a single hole around 500m southwest of the historic Prince Resource adjacent to the historic Redbank Mining Centre.
The VTEM-max survey completed by the company in 2021 identified an anomaly confirmed with ground IP to be a shallow chargeability anomaly with no corresponding conductivity.
NT Minerals reports drilling confirmed this to be a narrow sulphidic zone with visible pyrite containing weakly anomalous copper up to 0.27% Cu from 35m to 36m in 22VT12 in the Gold Creek Volcanics.
The company also reports this reconnaissance drillhole is the only test of the target for nearly 400m.
Towards 2023, NT Minerals reports regional geological understanding, prospectivity modelling and targeting can be cost effectively achieved over vast areas with focused geophysical surveys in conjunction with other foundation datasets, ahead of ground reconnaissance.
The company will be completing additional drilling at Calvert South to explain lithologically-controlled copper anomalism and to further explore the lower stratigraphic units such as the McDermott Formation, which NT Minerals considers to be the first reductant above the basal Westmorland Conglomerate.
It says this is analogous to sediment hosted copper models of the Central African Copper Belt, and the company is encouraged to move forward into 2023 integrating new regional soil results with work completed this year to strengthen future drill targets while analysing project-wide multielement geochemical signatures to locate unique identifiers for copper mineralising systems.
The Redbank Project is located in the southeast McArthur Basin and extends from the Northern Territory and Queensland border northwest to Glencore’s McArthur Mine.
In July 2020, Nt Minerals secured a district scale tenement holding, pegging open ground following ‘groundbreaking’ work by Geoscience Australia.
The company reports this work highlighted the prospectivity for Tier 1 base metal deposits between the deposits of McArthur and Century.
NT Minerals is a copper exploration company, and its assets include the Redbank Project and the Millers Creek Project in South Australia.
Images: NT Minerals Ltd