How can I disable the Riddler Proximity Mine in the Secret Corridor in Wonder City?

I've been playing Batman: Arkham City and there is a Riddler Proximity Mine in the Secret Corridor in Wonder City. I've tried to disable it using the Disruptor (as suggested in the answer to my previous question about disabling Proximity Mines) but it doesn't work (I'm aiming with LT and pressing RT, but there comes the "no sign" enter image description here).

I've also tried to find a way to that room which stores the Riddler Trophy, but to no avail (I've taken a look inside the room by throwing a remote batarang in it).

The only way in seems to slide under the bars but the mine must be disabled first. How can I achieve this?

Below are two images I took with my good old cellphone. Sorry for the low image quality.

corridormapdisruptor


The disruptor's the correct tool to use here. Perhaps you're just not hitting the mine with it properly? Do you have the upgrade which lets you detonate the mines? You'll have to hold the detonate button down (R2 on the PS3) in order to get it to explode.

You get this upgrade from:

the cops in the Iceberg Lounge, during the side mission Remote Hideaway.