Castillo Copper Ltd (ASX:CCZ) (LON:CCZ) (FRA:7OR) is gearing up to resume drilling at Mt Oxide Project in the Mt Isa Copper Belt of northwest Queensland off the back of a review of historical data that enhances the exploration potential of Arya prospect.
The historical reports include several commissioned by BHP Group Ltd (ASX:BHP) and Mt Isa Mines (MIM), with a 1997 BHP annual tenement report identifying 11 GEOTEM anomalies worthy of attention.
However, ground geophysics and rock chip sampling was only completed on four, leaving seven viable targets yet to be investigated.
Using aggregated historical rock-chip assay data of up to 1.84% copper (MIM), CCZ’s geology team created a maiden copper heat map that seamlessly reconciles with geophysical findings to boost confidence in drill-test targets at Arya Prospect.
“Compelling case for Arya”
BHP rated EG01 – which is interpreted to be a 130 metres thick potential massive sulphide bedrock conductor (1,500 metres by 450 metres and circa 430 metres deep) – as a priority drill-test target.
Secondary targets, comprising EG02 & EG10, are interpreted to be shallow 25 metres thick – with respective dimensions 160 metres by 50 metres and 280 metres by 270 metres – and may contain supergene copper mineralisation.
Castillo managing director Simon Paull said: “The board is very much looking forward to resuming drilling at the Mt Oxide Project, especially the Arya Prospect which has increasingly compelling attributes.
“While our main goal is to drill-test our primary target, EG01, the overall exploration potential has been boosted with a further seven targets identified by BHP and the Sansa Prospect.”
Sansa Prospect identified
In a fresh development, another deep bedrock conductor has been identified at the newly named Sansa Prospect, which is immediately west of Arya.
Encouragingly, there are elevated surface copper readings above the bedrock conductor, however, further interpretation work is required to formulate the dimensions and determine the prospectivity for copper mineralisation.
3D model showing planned drilling campaign at Arya prospect.
Copper heat map
Using aggregated historical surface data, the company has created ‘copper heat maps’ which show the extent of mineralisation across the Arya and Sansa prospects.
Notably, the effect is quite pronounced when using data for rock chip assays from various campaigns which achieved results up to 7,400 parts per million copper and 18,400 ppm copper respectively.
The aggregated data copper map has allowed the reconciliation of historical surface geochemistry assays with geophysical survey results, boosting the confidence in drill-test targets selected at the Arya Prospect.
3D model generates drilling insights
To garner better insights of the upcoming drilling campaign, comprising 3,625 metres across 14 drill holes, 3D modelling has been used to generate optimal results.
The company plans to undertake three deep vertical drill holes, spaced 210 metres apart, and ranging from 590-680 metres to test EG01.
The remaining 11 shallower drill holes will focus on EG02, EG10 and three highly anomalous peaks along the fault that runs through the Arya Prospect.
The company’s geology team and geophysical contractors are set to visit the site in the near term to respectively work on pre-drilling logistics and IP survey at the Big One Deposit.
CCZ’s drilling team will then return to site to commence work at the Big One Deposit before moving on to the Arya Prospect.