Look at the scalebar on the left of this hydrothermal system (our deposit is a little bit like the IOCG on the left mineralogically). Hydrothermal alteration systems aren't small. You got huge volumes of fluids boiling off a batholith that could very in size from a city block to a whole city.
Hot fluids tend to rise vertically which is why hydrothermal alteration systems have a strong vertical component. The pressures involved mean that the fluids with time will permeate horizontally through the surrounding rocks as well when they encounter resistance from above.
If our mineralising systems are 5-10 kilometres in length and up to 2km wide, they're going to have a vertical extent of at least a kilometre and probably much more.
That said, the size is not so important because drilling results to date give us a kilometre in strike which is more than enough at 1oz/t, let alone at 2-5oz/t. That's enough ore for at least a few years.
I just had another look at the petrology report
http://bbxminerals.com.au/wp-content/uploads/2017/09/click-here-to-view.pdf. Some impressive alteration going on. Disseminated haematite-magnetite and intense sericitization and kaolinization (alteration of feldspar to mica and clay) in the porphyry. Intense potassium metasomatism, saussuritization, serpentinization, biotitization of the plagioclase usually showing an orange tint due to the dolerites.
Haematite-magnetite alteration in the porphyry and biotite alteration in the dolerites are really exciting.
