A relatively new discovery in the Murchison, Ironbark is close to the initial Mulga Bill find, and RC drilling has continued to improve the potential of the Ironbark area, with the latest RC drilling delivering 1m at 193.5 grams per tonne gold within a broader 5m at 51.65gpt from 106m.
A further 5m at 1.85gpt was recovered lower in the hole from 127m.
Another hole returned 3m at 27.06gpt from 145m, including 1m at 79.8gpt, while an extensional hole that is the northern-most test of Ironbark delivered 5m at 1.99gpt from 37m.
Managing director Andrew Paterson said the third phase of RC drilling at the now 500m-long strike defined so far at Ironbark had delivered intersections "comparable to some of our best results at Mulga Bill", which is 1.4km to the west.
The prospect remains open to north and south and at depth, and is starting to demonstrate potential for open pit or underground mining, Paterson said.
Paterson said planning for further drilling was underway, with a focus on testing for possible plunging high-grade shoots within the wider mineralised zones.
Argonaut analyst Royce Haese said while it had originally appeared Ironbark was "second fiddle" to the larger Mulga Bill anomaly, the prospect of high grades in a simpler geometry has increased its importance.
The results of infill auger sampling over Ironbark South are expected within six weeks, and will help prioritise drilling for future aircore programs.
Recent auger sampling helped confirm the gold potential over 7km of strike south of Ironbark, with some bismuth anomalies that look similar to the original Mulga Bill target.
Ironbark was initially identified as a two-point auger anomaly, and work so far has defined multiple anomalies of similar tenor or better to the south.
RC drilling continues along the wider Mulga Bill corridor, including down at the Flagpole prospect to the south of Ironbark.
The results from regional aircore drilling completed in September are also expected imminently.
The Side Well project sits on the underexplored eastern limb of the Pollele Syncline, an area that was previously considered barren.
Great Boulder had A$6 million cash at the end of June.
Shares in the explorer, which have traded at 6.5-23c over the past year, were up 4% this afternoon at 9.5c, capitalising it at $40 million.
