So the study on coal slack should be enhanced in order to make it become a sort of resources.

加强对煤矸石利用的研究，以将其资源化。

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When the economy was firing on all cylinders, there was no capacity to spare, but in these slack times China has closed some of its oldest (and most inefficient) coal - and oil-fired power plants.

当经济全速前进时，中国无暇顾及上述问题；但在萧条时期，中国关闭了国内那些废旧(和最没有效率)的煤炭和石油发电厂。

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The innovation and effect analysis of slack coal separation system technology was introduced in Fangezhuang Coal Mine Co. branch, and some questions in the innovation were suggested.

介绍了范各庄矿业分公司选煤厂末煤分选系统技术改造及效果分析，提出了在改造过程中应注意的问题。

youdao

Renewable energy remains too expensive, too land-hungry, too unreliable and too small-scale to take up much slack, so cheap coal and newly abundant natural gas will do the job.

WSJ: After Japan's Earthquake and Fukushima Disaster, Matt Ridley on Gas-Fired Generation and Thorium | Mind & Matter

Natural gas, which emits 45% less carbon dioxide than coal, would take up most of the slack.

FORBES: OutFront