With the first bi-monthly shipment expected to be very close to being announced it's going to be interesting to see if SL1 are valued as a one hit wonder campaign miner or as a producer with several deposits under their belt and a truckload of relatively under-explored ground. Looking at the maps it seems that they are taking the age old approach of looking for minerals where there are known minerals.
The Macy deposit that they are currently working wasn't discovered by symbol but rather appears to have been mined for years, Symbol have simply gone about it at a larger scale within the framework of the current pro mining govt. The other targets appear to be very much in the same boat, they have already been discovered and artisanal workings are extensive. It's not a case of having to discover anything new, they simply go to where there is minerals and drill to see how far they extend which makes it some of the easiest 'exploration' in the world. The pictures below may show this better
Overview
River
Imperial Extension
Aisha East
Macy/Imperial
Imperial South/Taparo
Fulani
