When I read "mine", I thought of anti-personnel landmines and was confused why you'd want to radio-trigger those. These were demolition charges designed to des

When I read "mine", I thought of anti-personnel landmines and was confused why you'd want to radio-trigger those. These were demolition charges designed to destroy objects like bridges. According to https://www.quora.com/Is-it-true-that-the-Finnish-army-used-the-song-S%C3%A4kkij%C3%A4rven-Polkka-to-prevent-the-detonation-of-Soviet-radio-controlled-mines-during-the-recapture-of-Viipuri-in-the-Continuation-War/answer/Alexander-Denisov-9 https://www.quora.com/Is-it-true-that-the-Finnish-army-used-..., there were a total of 25 such mines hidden, with each containing hundreds to thousands of kilograms of explosives. https://www.standingwellback.com/russian-ww2-radio-controlled-explosive-device/ https://www.standingwellback.com/russian-ww2-radio-controlle... is also worth a read.