The name of this compound is lithium fluoride.
I mean each Animal has a purpose in order to keep the food chain in line, for example sharks if they went extinct there would be more seals and more fish and less of this and that. Each animal plays a certain part on earth in order to keep everything normal.
Coal seams are far deep underground to be considered for opencast minings. These coal seams require underground mining. Since it is too deep underground, it can be used for mapping and correlation of sedimentary rocks or as a key bed.