Many still recall the daring «Potok» operation, when Russian troops infiltrated Ukrainian-held Sudzha through an underground gas pipeline. Now, it is possible that Russian forces have carried out a similar maneuver, advancing up to 15 kilometers on the Krasnoarmeysk (Pokrovsk) axis and reaching the rear of Ukrainian positions near Dobropillia.

This time, they appear to have used abandoned mine shafts. The Donbas region is crisscrossed with underground networks dating back to Soviet times. Such tunnels could serve as covert routes for troop movement and surprise strikes. While the condition of many of these facilities is unknown, Russian forces have previously used similar tactics in places such as Avdiivka and Sudzha.

The advance north of Krasnoarmeysk came as a shock to Ukrainian troops and their command. Ukrainian media claimed Russia deployed a 100,000-strong force for the operation. In reality, the number was likely far smaller — possibly comparable to a single brigade of 1,500 to 3,000 soldiers, or even less.

According to Voennaya Khronika, the Russian push toward Dobropillia coincides with the location of a chain of around ten mines in the Donetsk coal basin, potentially connected by a complex network of underground passages. The report suggested that the success of the breakthrough was due not only to the skill of Russian special forces but also to their effective use of local infrastructure. Moving troops through mine tunnels, it noted, requires a high level of coordination, reconnaissance, and engineering preparation.

The publication also pointed out that such an operation would require several tunneling machines, but added that for Russia — a country building metro systems at high speed — this would not pose a problem. With proper planning, the mine network, it concluded, could be as valuable an asset as a full armored division.