Spectrum Metals (ASX:SPX) continues to hit paydirt after drilling the deepest hole ever into its company making Penny North discovery.

Spectrum went into the stratosphere earlier this year after hitting bonanza gold grades at the historic Penny West gold mine in WA.

The explorer’s ongoing success illustrates just how much potential there is around (and underneath) Australia’s historic gold mines. Now everyone is doing it.

The latest four reverse circulation (RC) holes punched into Penny North — next to the historic Penny West pit — were designed to chase the existing high-grade gold shoot at depth.

These latest results included 6m at 10 grams per tonne (g/t) gold, 348m from surface — the deepest hole drilled by about 80m.

The high-grade shoot within the Penny North lode remains open down dip, Spectrum says.

By the way, when companies talk about going ‘along strike’ or ‘down dip’ this is what they mean:


This RC drilling has now largely defined the orientation of the main mineralised lode at Penny North, Spectrum managing director Paul Adams says.

“It is extremely predictable and robust,” he told Stockhead.

“Having said that, the size appears to keep growing as we put more extensional holes into the system.”

Spectrum also drilled the first of four diamond holes into Penny North, intersecting the 2m-wide gold lode “on target” at 221m down hole. Core will be processed in due course, the company says.

Diamond core from Penny North.

This diamond drilling can tell Spectrum a lot more about the orebody than RC does, Adams says.

“With RC you only have a handful of rock chips — you can’t actually see the rock as it would appear, for instance, in an underground mining face,” he says.

“The details and nuances that can be gleaned from diamond core far outweigh the additional costs of drilling, and there are many studies that can be done on core that can’t be done as well on RC chips.

“The infill program of diamond holes will definitely help in producing a JORC resource, but it is important to know that diamond drilling is not essential for its completion.”

For example, this diamond hole showed excellent rock ‘competency’ at depth, which basically means the rock doesn’t fall apart easily. This is a good thing.

“If you are mining underground and your walls keep unravelling or flaking off it would require additional ground support, which is time consuming to put in place and adds cost,” he says.

“A competent rock mass has many advantages over one that isn’t.”

READ MORE about Spectrum:

Spectrum Metals’ Paul Adams on dodging bullets and that 1 month, 525pc share price increase

Spectrum plays it cool, but Penny West could be turning into a monster

Spectrum’s now up 82.5pc in a week as Penny West just keeps on giving