A huge black smoke would have been a diesel fuel burn. If left to it's devices, the fuel burn would ignite the ammunition stores soon enough.
In the case if a tank is disabled but recoverable, it won't be burning diesel for two whole days. If the tank is recoverable, it's likely it won't be burning, so you send a quadcopter to send a grenade down the hatch.
An example of one. A Ukrainian tank being disposed of by a Russian drone by a grenade down the hatch. The tank is in recoverable condition but the crew has left the scene. The tank itself was an ex-Russian captured tank. The tank however isn't burning. If there was a fire it would have been momentarily from a mine or from other causes but it didn't ignite the fuel to create huge black smoke.