Hi MFU
Sulphides are normally high in mineralisation. If you think of volcanoes when they erupt sulphur gas comes out.
If there’s sulphides more likely evidence of a volcanic intrusion.
Sulphur is found attached to various other minerals, importantly Chalcopyrites.
This has a chemical formula Cu Fe S2
That’s copper iron and sulphur containing about 35% copper formed at high temperatures.
This is our main source of copper, sometimes mistaken for fools gold but does contain a small % of gold.
Arsenic also forms with sulphur and also contains some gold especially in Tellurium.
Asbestos too combines with sulphides and may be why the actinolite breccia have higher gold concentration.
Iron and sulphur combine to form pyrites very prevalent in Havieron ore don’t get fooled when looking at cores you very rarely see the gold.
Breccia is different our first intrusions formed breccia possibly just heat not sulphides. This heat not only cracked the rock into clasts ie small rock shapes and may have moved them slightly, but also drew in mineralisation from the surrounding rocks , concentrating them in the breccia.
Which is why the weaker breccia are around the perimeter.
Later intrusions insert quartz into the cracks of the breccia leaving mineralisation in small veins which is why cemented breccia has more gold and is coloured blue on most sections.
It’s these that have been increasing over time as drill knowledge has displaced the crackle breccia marked yellow on the plans
I hope this explains what you were after, please ask again if not
