low grade ore

基本解释

He also knows that big mining companies prefer mountains of low-grade ore to small, high-grade mines like his.
而且他也知道那些个大型矿产公司更喜欢那些低地势的矿山，而不是他那又小又高的。
These areas had already been rejected by the industry’s giants as too costly to develop because of their complex geology and relatively low-grade ore.
这些地区地质结构复杂，相关的铁矿石品位低，开发成本过高，早已被一些矿业巨头舍弃。
Although much of the high-grade ore has been used, there remains enough low-grade ore to last for centuries.
品位高的富铁矿已经开采很多，品位低的铁矿还够开采若干个世纪。