Million years [1]. (It devitrifies.)

> asphalt of the roads may dissapear, but the gravel mixed with it and under it will create a very strange pattern

Would this be recognisable at an industrial scale?

> Panama and Suez channels

Suez is right above the East African rift, so maybe 10 My. Panama no clue.

> Quarries and coal mines are huge

To where they could evidence industrial activity after millions of years?

[1] https://education.seattlepi.com/long-glass-bottle-degrade-la...

> Million years. (It devitrifies.)

Very interesting. It's difficult to get hard numbers. It depends a lot on the composition and the temperature, so I'm more optimistic about they lasting for a few millons years at burried at 15°C(60°F), but I agree they don't last forever

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>> asphalt of the roads may dissapear, but the gravel mixed with it and under it will create a very strange pattern

> Would this be recognisable at an industrial scale?

I guess so. We have a lot of roads with a not random patterns.

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>> Panama and Suez channels

> Suez is right above the East African rift, so maybe 10 My. Panama no clue.

I agree. Both are in bad positions to last forever.

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>> Quarries and coal mines are huge

> To where they could evidence industrial activity after millions of years?

I guess they are. Look at this video https://www.youtube.com/watch?v=fjp6RHb7MtE the truck are huge, from time to time there appears a normal truck next to them and it looks like a toy truck. I think when abandonded they get filled with water, then with mud and decomposing plants, and then that will solidify and in the future they will have a huge "volvano caldera" but no volcano at the bottom. Also find the internal roads, cuts by explossions and other strange characterisitcs. The truck will have rot a long time ago and dissapeared, but they may find unusual levels of iron contamination in the parking lot.