Making Marbles

I'd been told that marbles were made using shaker tables to round the blobbed, swirled glass 'drops' into spheres. So I went hunting for a video to see that.

That clearly is not how this company makes their marbles.

Instead, this looks to be some sort of screw drive processing as the glass cools followed by a really long run to - I assume - keep the marbles round while they're cooling further.

If anybody finds a marble production video using the shaker table method, please share it.