Full G on the Moon or other small bodies?

On 1/11/07, Jake wrote:
(...)
> Maybe... But a ring built around the moon as suggested, or the Taurus
> wheel built on the surface as suggested would have to be quite big..

A ring around the Moon (a la Starship Troopers, illustrating with yet
another movie...) built with lunar materials would be
mass-conservative. From the point of view of Earth, the Moon-Ring
system would have exactly the same influence on tides as the
Moon-alone system, and Moon's orbit would remain the same. The same
would apply to a surface ring around the equator (if that is what you
mean).

(...)
> All the mining we do on earth stays on earth (for the most part)..
> Although the earth is so large we would have a really hard time making
> much difference, but we are talking about mining a small body that
> orbits our own planet..
(...)

I have seen you putting too much emphasis on the Moon being "a small
body", and I am beginning to think that you don't have a clear idea
about how ENORMOUS it is, although small as planet-like bodies go.

The diameter of the Moon is 1/4 of that of Earth: were Earth a melon,
the Moon would be an apple. The total surface area of the Moon is like
that of the whole Africa. Now, the whole African continent has been
extensively mined for centuries, and nevertheless we did not impaired
the geostatic equilibrium of the continent and made it sink in the
magma or any other Superfriends-type catastrophe like that. And
remember that I am comparing just surfaces, the Moon has volume and
its mass is in fact orders of magnitude larger than that of a
continental plate...