Slovenia

Slovenia (スロベニア), officially the Republic of Slovenia, is a country located in southern Central Europe. Slovenia shares borders with four countries; Italy to the west, Austria to the north, Hungary to the northeast, and Croatia to the southwest.

Background
The New Energy Mining Agency (新エネルギー採掘研究機関) is located in Celje, Slovenia.

Toaru Majutsu no Index Light Novel Volume SS2
On the Second Friday of October, Misaka 12481 was one of the Sisters sent to Gemstone Mining research organizations around the world. She was sent to Celje, Slovenia, at the New Energy Mining Agency, to destroy the facilities and rescue the gemstone there. During her periodic progress report, she had just found the Gemstone that was at that facility.