Ndi kugonjetsedwa ndi kukokoloka ndi moyo wautali wa ntchito zomwe zingathandize kwambiri pobowola effeciency ndi kusunga mtengo.
Ndioyenera kupangika pamaumbidwe ovuta kwambiri, monga sandstone.
Nambala yazogulitsa: DNC201
IADC: M712
Kubowola pakati mpaka zovuta.
Ndioyenera kuperekera mawonekedwe apakatikati mpaka ovuta pamlingo winawake wamapangidwe abrasive.
Ndioyenera kuchititsa ma coring mumapangidwe apakatikati komanso ovuta okhala ndi nthawi yayitali yamoyo.