Choose don't over a long period of time, high, but the concentrate recovery from the eduction is close to ore mouth, magnetic double function poor, so concentrate grade is relatively low.

选别时间较长，回收率较高，而精矿排出端离给矿口较近，磁翻作用差，所以精矿品位较低。

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This paper introduced emphatically to mining method for the ore-body of gentle dip and medium thickness under the condition of medium or poor stableness of country rocks in upper wall.

本文着重介绍缓倾斜中厚，上盘围岩中稳到稳固性较差条件下的矿体的采矿方法改进实践过程。

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Rutile resource is rich in our country, but rutile ore grade is low and the product is poor competitive because of its high production cost.

我国天然金红石资源储量较大，但绝大部分为低品位的原生矿石，所以加工成本高，产品缺乏市场竞争力。

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Stephen Briggs, metals strategist at BNP Paribas, believes that poor ore grades, namely from major mining companies, are at the top of the list for poor mine supply this year.

FORBES: Analysts Look For Decline In 2011 Global Copper-Mine Production

Barclays believes the main reasons for these declines stem from poor ore grades being mined as well as disruptions in the form of strikes, with some pipeline cuttings, and poor weather.

FORBES: Analysts Look For Decline In 2011 Global Copper-Mine Production

Several experts in the field outlined several issues that they said point to a decline in the mining industry, from poor ore grades to declines in drilling activity to misinformation on the investment side.

FORBES: PDAC: Many Factors Putting Mining Industry At Risk