jīng / guò / jì / shù / gǎi / zào / hòu / yuán / běn / nán / yǐ / lì / yòng / de / kuàng / shí / yě / biàn / de / kě / cǎi / le

经过技术改造后，原本难以利用的矿石也变得可采了。

After the technical upgrades, the ore that was previously difficult to use also became workable.