Prior to starting of open cast working some trenches are excavated to expose mineral body. The trenches are very long but limited depth; what is approximate depth.

A. Working time B. Rest internal C. Night D. All

A. Rifle bullet test B. Gap test C. Ageing test D. Water resistance test

A. Striping B. Open cast C. Placer D. Long wall

A. 0.25 to 0.75 B. 3 to 4.5 C. 1.5 to 1.7 D. None