When dealing with mineralisation it refers to:Along Strike - for...

When dealing with mineralisation it refers to:
Along Strike - for example, let say the mineralisation appears to follow a certain direction i.e North East - South West. Explorers will make their discovery, then proceed with step-out drilling (in this direction) until they cease to find further mineralisation i.e. mineralisation strikes along a northwest structure for 500m. Until the 'end' of mineralisation is confrimed, it's referred to be 'open' along strike.

Depth - same same as above, just a vertical extension of the mineralisation. A series/fence of holes is usually required to top/tail exisiting drilling to determine how deep the mineralisation continues.

TO complicate matters, mineralisation can often be off-set/dispalced by post mineralisation activity such as faulting. As such, in order to 'close' off a mineral system, explorers need to also understand local structural geology to determine if there is the potenital for mineralisation to continue in a different/dislocated area.