Using hydraulic supports in heavy grade longwall face with sublevel caving, anti-topple and antiskid are the key factors.

在大倾角倾斜煤层进行综放开采，支架的防倒、防滑成为决定放顶煤开采成功与否的关键。

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You start with heavy-grade sandpaper. Then, you move to finer-grade sandpaper.

先用粗颗粒的砂纸磨，然后再用细颗粒的砂纸。

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But any extra Saudi oil released now will be too late in arriving and too heavy a grade to keep America's drivers happy.

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Nothing that would make the tablet uncomfortable to use, but enough to remind you there's a heavy-duty, laptop-grade processor inside.

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Much of Venezuelan oil is also heavy oil, which is a lower grade.

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