I created 4 beacon pyramids right next to each other in creative. Then I switched my gamemode to survival and removed the beacon block. The beacon beam did not disappear. I then removed several of the pyramid blocks and the beacon beam still did not disappear.
The beacon with 4 layers has an unconsumed iron ingot sitting in its interface. The rest of the beacons do not have any ignots/gems sitting inside them.
Attached is a screen shot.
Upon reloading the world, the beacon beam is gone and the iron ingot in the 4 layer pyramid beacon is gone.
Environment
OS: Windows 7 Home Premium Service Pack 1
Java Version: 1.7.0_45 64 bit
Display: 1600x825 NVIDIA Corporation GeForce GTS 450/PCIe/SSE2 4.30
Ram: 8 gigs total, allocated 2 gig to minecraft
Duplicates MC-59533