An increasing number of major mining companies is attracted by deposits to be mined underground – not only because the surficial disturbance and environmental impacts are less than with open-pits but also because these can be highly economic due to low operating costs. In this regard, among the most attractive deposit-types is sediment-hosted copper as its ore zone typically runs continuously for long distances (up to several kilometres, or hundreds to a thousand kilometres through Germany and Poland or the prolific Congo Copper Belt). And when the width of the ore zone is just a metre (or even less!), that‘s just great news for underground mining engineers and shareholders alike.