Zida zobowola mozungulira mozungulira
Kubowola kwa Reverse Circulation (RC) ndi njira yomwe imagwiritsidwa ntchito pofufuza mchere ndi migodi kusonkhanitsa zitsanzo za miyala pansi pa nthaka. Pobowola RC, nyundo yapadera yoboola yomwe imadziwika kuti "Reverse Circulation hammer" imagwiritsidwa ntchito. Njirayi ndiyothandiza kwambiri popeza zitsanzo zapamwamba kuchokera kumiyala yozama komanso yolimba. Chida chobowola cha Reverse Circulation ndi nyundo ya pneumatic yomwe idapangidwa kuti ipangitse mphamvu yotsikira pansi poyendetsa pobowola pamiyala. Mosiyana ndi kubowola kwachikale, pomwe zodulidwazo zimakwezedwa pamwamba kudzera pa chingwe chobowola, mu kubowola kwa RC, kapangidwe ka nyundo kamalola kuti zodulidwazo zizizunguliranso.