It can be easy to miss news released at the end of the week, but investors focused on the rare earth elements (REE) space likely won't want to lose track of last Friday's announcement from US Rare Earths (OTCQB:UREE). The company capped the week off by revealing that it has received approval from the US Forest Service to re-open the Last Chance northern adit. In doing so, it will gain access to the Last Chance vein, which it says is "one of the longest identified mineralized veins in the Lemhi Passarea of Idaho and Montana." What's in an adit? Understanding the significance of US Rare Earths' news requires one simple piece of geological knowledge: what is an adit? Put very simply, an adit is a horizontal or near-horizontal entrance to an underground mine. Adits can be used for water drainage, ventilation or simply to extract minerals, and are generally preferred over vertical shafts as they tend to be cheaper; indeed, adits of between 1 and 2 miles can be economically feasible. From the sounds of it, US Rare Earths will certainly be privy to cost — and time — savings. As CEO Kevin Cassidy said, "[w]e estimate that the opening of the Last Chance existing adits will save the company approximately $6 million and reduce our development time by at least three years." He added that the move will put the company "well ahead of [its] peers and well on [its] way of executing our strategy of providing a complete domestic supply chain solution of critical rare earths which are made in America." Also significant, said Cassidy, is the fact that US Rare Earths now has "the prospect of being the first underground mine since the 1960′s in the US to remove rare earth material."