The second pipe of the Karavanke Tunnel between Slovenia and Austria is a joint project. Austrians dig from their land to the Slovenian border and the Slovenians from their end to Austrian border.

Austrians have already successfully reached the Slovenian border (link below has nice pics) whereas the tunnel construction on the Slovenian side is to take two more years to finish. This is thanks to the lengthy tender process in Slovenia. It took two tenders to finally award a contractor for the work on Slovenian side. In the first tender, DARS (Slovenian road company) had already awarded the contract for the construction of the second tube of the tunnel to Turkish company Cengiz Insaat Sanayi ve Ticaret, whose bid of EUR 89.3 million excluding VAT was significantly cheaper than the remaining eight bids. The process was then halted by three loosing contractors (Slovenian builder Kolektor CPG,  Bosnia's Euro-Asfalt and its Slovenian partner Cestno Podjetje Ptujm) who filed audit claims. Also claimed Cengiz did not submit full certificates for its personnel. After a long process there was a new tender and again Cengiz has been awarded with even higher amount. The whole thing has cost Slovenia more money and ridiculous amount of time.

https://fucaa.com/slovenia/the-austrians-have-already-dug-into-slovenia-these-are-photos-of-the-foto-celebration/