Hi Ken,
While I am also reasonably sure that they aren't planning to try to remove the entire slide, 250-300 tons still seems awfully small in the overall scheme of things.
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If we accept, according to my engineering texts, that some good solid granite weighs on the order of 2 tons per cubic yard, then we're talking about roughly 125 to 150 cubic yards of material to remove, as stated in the article (250 tons/2 tons per CY=125 CY, 300 tons/2 tons per CY=150 CY). Mind you, now, this assumes no air voids in all of this shit, a conservative approach.
Now assume that the width of the removal is, say, 30 feet wide (this assumes two 12-foot-wide travel lanes plus a small shoulder area on each side). Taking 150 CY and converting to cubic feet, then dividing by the width of the removal for the roadway leaves an area (that must, by definition, be formed by the length of the slide along the buried portion of the roadway times its height above the roadway surface that needs to be removed) of 135 square feet.
If the length of roadway covered by the slide is, say, 30 feet (just a coincidence that I used the same value for the width to be cleared; it really doesn't matter for the purpose of this illustration, as you'll soon see), then that means that the depth of the slide across the road is somewhere in the neighborhood of 4.5 feet thick.
Now, given the dimensions of the slide that are stated in the article and the attendant hub-bub that the media has made of the event, I find it rather difficult to believe that the dimensions of the roadway clearing could be this small (30 feet x 30 feet x 4.5 feet thick = 150CY = 300 tons) for a slide of a magnitude of 4 million cubic yards. Hence my earlier comment "250-300 tons sounds trite."
QED
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Of course, I could be wrong.