regolith-hosted rare earth element deposits
... that regolith-hosted rare earth element deposits are mostly low grade, but economic to mine?
... that <b id="mwBGw"><a href="./Regolith-hosted_rare_earth_element_deposits" id="mwBG0" rel="mw:WikiLink" title="Regolith-hosted rare earth element deposits">regolith-hosted rare earth element deposits</a></b> are mostly low grade, but economic to mine?