The Aldo Army's operation to destroy the dwarven tunnels had achieved far greater success than expected. The tremendous power displayed by the Picric Acid-based Yellow Explosive in actual combat had completely overturned conventional understanding of demolition warfare.
Unlike Black Powder, Yellow Explosive was a true high-energy brisant explosive. Its detonation was not combustion, but detonation—a chain chemical reaction that propagated at supersonic speed. Its shock wave traveled at over seven thousand meters per second, far faster than sound, tearing and pulverizing rock from the inside in an instant.
Black Powder, although the people of Northwest Bay now habitually called it "explosives," was actually a low-velocity explosive. In essence, it relied on rapid burning, or deflagration, followed by the thrust produced by expanding gas in an enclosed space. If Black Powder was ignited in the open air, it would only produce a burst of flames and thick smoke, unable to form a destructive shock wave. Only when sealed inside a cannon barrel, rock cavity, or iron pipe could it "blow open" a target.
For that reason, when using Black Powder for demolition in the past, the Northwest Legion's engineers had to drill holes, load the powder, tamp it down, and seal it with mud. The slightest mistake meant they had done nothing more than set off a smoke bomb. Even when successful, it could usually only crack the rock formation, making it difficult to destroy it completely.
Picric Acid was different. Even when ignited in an open environment, it would undergo a violent explosion—in other words, detonation—producing a powerful shock wave and destructive force. This was fundamentally different from Black Powder.
During this operation, Yellow Explosive had still triggered violent detonations inside the tunnel despite it not being completely sealed. The three charges detonated one after another, directly collapsing the main