Can anyone give any clues to the actual way the towers operate?

I have never seen it described, but I do recall (might have the numbers wrong) that for every metre above the surface of the earth the potential (voltage) rises by 100millivolts, and it would be logical to assume that while the surface of the earth is conventionally labelled zero volts (earth potential) if you were to dig down you would be seeing negative voltage.

In electrical theory a circuit with a potential difference causes current to flow, so, if your tower was part of a circuit with one end above the ground, and the other end below ground there would be a potential difference, and cabling from those points to a machine would result in a current flowing - free energy gathered from static electrical charges that are an artefact of the earths magnetic field, caused by it spinning in the suns electric field and perhaps some contribution from the iron core of the earth spinning in that field.

This is just my supposition, I have never heard anyone explain how the towers actually function, this is my best guess. If I am correct, the tower is a very very simple device and anyone could test it if they had a well, and a tower or tall house. Drop a metal ball into the well attached to an insulated cable and bring to a terminal at ground level, then connect another terminal to a metal ball at the top of your house and now measure the potential difference between these two terminals. If you have one, connect a suitable lamp/lightbulb to it and just see what happens, presumably you would have free electricity if this is how the towers work.

Sometimes I wonder if the pyramids of Egypt were exactly this - a metal capstone, and in the underground cavern under the pyramid, another collector, and wires between them into the kings chamber where the electricity is used, perhaps to refine metals, like aluminium which can be produced by electrolysis of suitable solutions (of bauxite in the case of aluminium). I know you can copper plate things like this also.