"掏槽深度" can be translated into English as "cutting depth" (in the context of excavation or tunneling operations where a "cut" or "slot" is made) or more specifically as "slotting depth" when referring to the depth of a slot being excavated.
However, in engineering and mining terminology, "掏槽深度" is often directly translated or understood in technical discussions as "depth of the cut (for slot excavation)" or simply referred to with context-specific terms like "depth of the slot being excavated".
For a concise and technical translation, "cutting depth" is commonly used, especially when the action involves creating a slot or cut in material (e.g., rock, soil). If the context is more about the slot itself, "slotting depth" could also be appropriate.
In summary, the most straightforward and widely understood translation would be:
Cutting depth (for general excavation or cutting operations involving a slot).
Or, with more specificity:
Depth of the slot excavation (if emphasizing the slot being created).