1. Na-arụ ọrụ ndị ọrụ pneumatic rock drills,Tupu agbada n'olulu mmiri ga-eyi ezigbo ngwá ọrụ nchebe nke onwe.2. Ịbịarute n'ebe ọrụ, buru ụzọ lelee nhazi, ịkụ aka n'elu ụlọ, wepụ ihe mkpuchi ahụ, lelee ndị ọrụ sled ka ha mee nchedo onwe ha, ka a na-elekọta ha ...
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