Antilles Gold Ltd (ASX:AAU, OTCQB:ANTMF) has completed four preliminary diamond drill holes totalling 1,110m downhole on the El Pilar copper-gold porphyry deposit, and its overlying gold-copper oxide deposit in central Cuba.
All four drill holes have been collared along 300m of strike of the El Pilar porphyry copper-gold oxide exposure and have tested both the high-grade gold domain and the lower leached copper domain.
Additionally, all the drill holes continued into fresh rock where porphyry-style hydrothermal alteration, veining and copper sulphide mineralisation were encountered in varying amounts, representing the outer mineralised halo of a prospective copper-gold porphyry system.
An additional three drill holes in the current preliminary program will target both the oxide and sulphide zones to better define the extent and style of the alteration system for the upcoming ground induced polarisation (IP) and ground magnetometry (magnetics) surveys over an area 3km x 2km that will cover the very large El Pilar surface geochemical and alteration footprint.
“Important phase in the company’s progress”
Antilles executive chairman Brian Johnson said that the early positive indications of the potential of both the El Pilar copper-gold porphyry deposit, and its overlying oxide deposit, will obviously become more certain once preliminary drilling results are received next month.
He is predicting an important phase in the company’s progress next year with the proposed development of the La Demajagua gold-silver mine, and a significant exploration campaign being carried out concurrently.
Johnson added: “The company is looking forward to potentially becoming a copper producer in the not too distant future, initially from the El Pilar oxide deposit, and subsequently from the underlying porphyry deposit.”
Exploration director’s observations
While assay results from the diamond drilling at El Pilar are expected in about four weeks, observations of mineralisation in the completed holes by the company’s highly experienced exploration director Dr Christian Grainger are as follows:
The four drill holes in the oxidised cap indicated continuous gold mineralisation from near surface to +40m downhole in the upper gold domain dominated by iron-oxides after primary sulphides, and then +45m of oxide copper mineralisation in the underlying copper domain that is almost entirely composed of secondary chalcocite, and lesser chalcopyrite.
All drill holes in fresh rock have intersected visual copper sulphide (chalcopyrite) mineralisation in what is interpreted as the outer zone of the porphyry deposit dominated by intense chloritesericite hydrothermal alteration associated with veins, breccias and stockworks of chalcopyritepyrite which is indicative of a porphyry copper-gold system.
Earlier potassic alteration (secondary biotite) is present locally in diorite dykes that display pervasive chlorite overprinting and chalcopyrite mineralisation.
Dr Grainger inspects a drill core.
Next steps
A 15,000-metre drilling program is planned to commence in Q2 2023 and target the porphyry copper-gold mineralisation that is not exposed in the flat terrain which has little outcropping exposure outside of the oxide cap as it is a topographic high.
The targets will be generated by the upcoming ground IP and magnetics programs.
A separate 7,000-metre shallow (100m vertically) program will be undertaken on the oxide cap, commencing Q1 2023.
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