In order to reduce the coal loss and raise recovery ratio, the technique measures of backing poles and falling the bottom are adopted. The recovery rate of face resources is raised.

为了减少煤炭损失，提高回采率，在加采到底煤较厚地段时，采取背杆落底技术措施，提高了采面资源回收率。

youdao

This ratio helps noteholders sleep at night because they believe there is more than enough collateral backing their investments.

FORBES: Lynn Tilton's Financial Empire: More Details, More Trouble