I roto i te mahi kari kari, ko te whakamāramatanga paerewa o te whai hua, he tukanga e whakapai ake ai (painga) the economic value of mined ore. Removing valueless materials, results in a higher grade of

I te Rātapu, 22 o Āperira, whakanuia e te ao te Rā o te Ao. Kua tīmata i roto i 1970 kua whakaritea hoki he take ā-tau i taua rā, te wāhi e puritia ai ngā takahanga maha ki