English to Russian Tech/Engineering Mining & Minerals / Gems Iron ore mining

Из следующей фразы, описывающей рудник:
Each hole averages 50 meters (165 feet) in length and, while the direction and number of holes varies depending on the structure and orientation of the ore at that location, most *“production fans”* contain 10 holes resulting in 10,000 metric tonnes (11,000 short tons) of ore being blasted per 3.0- to 3.5-meter (10- to 11.5-foot) slice.