Low strip ratio can present some practical challenges in a...

Low strip ratio can present some practical challenges in a greenfield development because building ramps, roads, pads and windrows is usually done with waste /prestrip material. It could mean that you end up sacrificing some low grade material for those purposes if everywhere you dig you come up with spod.
I think in the case of Manono given that it's an existing pit there's probably enough waste around in existing dumps (assuming no-one is planning to reprocess that material).
If the operation was in a really sensitive heritage area it might limit where you can get waste from but to date I haven't read anything about heritage concerns.
Any challenges the strip ratio presents are generally worth having