another 10 gold (tungsten) bars detected., page-8

I smell a rat with this story. Something doesn't add up.

Firstly, there are sooo many ways to test non intrusively, so there is no excuse for a NY bullion dealer with 40 years experience to destroy a pamp bar with the drill he uses to build his deck on the weekend):

How about coefficient of thermal expansion?  I expect it would be rather different for gold than tungsten.  Differences could be detected with strain gauges on the surface - too much/little surface strain, and the center isn't pure gold.
Also thermal conductivity.  The value for gold is huge.  I expect that tungsten is fairly resistant.  should be a simple thing to put a heater on the surface and check the temperature on the other side.

Also consider simple strain.  Suspend the bar on blocks on either end.  Load the center and measure the deflection.  Should be quite a difference between a solid gold and tungsten filled bar.  Do the same test but "ping" it with a shock force and look at the vibration signature.  Better yet just put a pieze electric on it and run the total frequency spectrum - Bode plot.  The differences should jump right out.  This is all pretty simple stuff.

IMO, these pictures look like they were designed for a media shock. Perhaps the whole thing is a setup to unsettle to gold market.