He mea motuhake te ringa toka Kaiyuan i tāutahia ki te keri Cat 385, nā ōna āhuatanga whakamiharo me tōna hoahoa auaha.
He maha ngā mahi a Rock Arm, he ringa whakarerekē maha-kaupapa, ā, he pai mō te keri me te kore e pupuhi, pērā i ngā maina waro tuwhera, ngā maina konumohe, ngā maina phosphate, ngā maina koura onepu, ngā maina quartz, me ētahi atu. He pai hoki mō ngā keri toka e tūpono ana ki ngā hanganga taketake pērā i te hanga rori me te keri o raro whenua, pērā i te uku mārō, te toka kua pakaru, te kirikiri, te toka, te kōhatu ngohengohe, te onepū, me ētahi atu. He pai ngā pānga, he kaha teitei o ngā taputapu, he iti te tere o te pakaru, he nui te whai hua o te pūngao ki te whakataurite ki ngā hama pakaru, ā, he iti te haruru. Ko Rock Arm te whiringa tuatahi mō ngā taputapu kāore he āhuatanga pupuhi.
