Drilling has confirmed Bryah’s Windalah copper-gold prospect has all the textbook geology of a beautiful volcanogenic massive sulphide.

That’s good news for the company as VMS systems in the Bryah Basin, Western Australia, are known to host some terrifically high-grade copper-gold deposits such as Sandfire’s DeGrussa and Monty mines as well as the historic Horseshoe Lights mine just 13km to the north.

Adding further interest, Windalah’s sulphide-rich zone occupies the same stratigraphic position as the Horseshoe Lights deposit.

Bryah Resources (ASX:BYH) recently completed a six-hole diamond drill program which also returned geochemical, hyperspectral and structural information suggesting the copper-rich mineralisation is likely at a greater depth than current drilling, while allowing the company to refine its targeting for the next round of exploration.

The company now believes the upcoming (exploration incentive scheme co-funded) drilling at Olympus targets a different part of a similar hydrothermal system to Windalah and may also be stratigraphically equivalent to the Horseshoe Lights copper-gold mine sequence.

“Having visual confirmation that we are within a VMS system is a massive step forwards for this project. The sulphide stringers in the distal parts of these deposits are usually from cooler fluids and without copper,” chief executive officer Ashley Jones said.

“The aim now is to vector within the VMS system and find the ‘hotter’ area where the copper mineralisation should be deposited. Seeing some secondary copper minerals in veins is also encouraging.

“Bryah’s geology team is using external experts, hyperspectral, geochemical, alteration, and structural observations to zero in on the ‘hot’ target zone.”

He added that the company’s growing understanding of the area has allowed its exploration team to use more refined techniques to advance other prospects like Olympus.

“With the Narracoota geology hosting the Horseshoe Lights and DeGrussa copper mines, we certainly have the right address to explore,” Jones says..

Drilling deep into some solid understanding

The six-hole program totalling 1,260m had greatly improved the company’s understanding on the geology and potential controls on mineralisation at Windalah.

Drilling identified the orientation and intersected laminated ‘syn-VMS’ stringers and the ‘ore stratigraphic horizon’ analogous with the Horseshoe Lights mine, generating a steeply plunging target window.

It also resulted in an improved schematic syn-depositional model that places current drilling on the periphery of an exhalative massive sulphide apron in a high sulphidation VMS system.

Windalah lies on the southern limb of the Mars Dome, which forms part of a series of double-plunging anticlinal dome structures in the northern Bryah Basin.

These dome structures connect laterally with outcropping Narracoota Formation to the northeast through a series of possible covered dome and basin structures

The contact with overlying Ravelstone Formation sediments is marked by an intermediate felsic transition facies that is lithologically and geochemically similar to the Horseshoe Lights mine stratigraphy and may represent an evolved, fertile magmatic setting for the development of shallow marine VMS deposits.

That’s pretty terrific news, by the way.




This article was developed in collaboration with Bryah Resources, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.