development work,exploratory development work /ENERGY-MINING,ENG-ELECTRICAL/
[DE] Ausrichtung
[EN] development work; exploratory development work
[FR] travaux préparatoires au rocher
development work,preparatory development work /ENERGY-MINING/
[DE] Vorrichtung
[EN] development work; preparatory development work
[FR] travaux préparatoires en veine