Tubes Between Mine And Smelter Instead Of Trucks

[croxis]

I also support using tubes as transport.  As mentioned a starting colony has few resources, so trucks would work better and can start an operation faster, but a destructable tube system would cost more in time, as it would take longer to build a tube out to the mining station.
As long as tubes can be attacked I think a tube system could still replace the truck system.

Should tubes have a capacity limit, so if the mine produces more than the tube allows a second parallel tube is needed?

[BlackBox]

I would say a capacity limit, if you exceed a maximum flowrate / pressure like in real life the tube would get damaged.

And to say you wouldn't need to defend your mining route isn't true since enemies could break your tube. (which would be more undetectable since a tube isn't a building).

Perhaps have it so only common ore mines can have tubes connected (say rare ore is too hard to transport via tube).

As for speed, being realistic, it would be faster to transport via tube. Cargo trucks have a finite capacity and the flow of ore isn't exactly continuous. It's also cheaper since the trucks need some sort of power source to continue running, as well as complex computers to control them.

Another angle you could look at the tubes from is, perhaps instead of a pipeline, just have them as a transportation system where trams of some sort shuttle ore from the mine. (That's how they are in OP2 according to helpfile / stories. People push around carts and ride electric bikes).

And by the way, the Ore itself isn't in a slurry but the refined metals are. I think the ore is just solids. This would pose another problem transporting via pipeline.

You could have negative consequences as well, for example blight or whatever can infect into the base easier (the help file makes reference to blight leaching into mined ore). This way the blight enters the base faster.

[Mcshay]

...Another angle you could look at the tubes from is, perhaps instead of a pipeline, just have them as a transportation system where trams of some sort shuttle ore from the mine...

Like the Monarails in op1. They were basicaly a bit faster than paved ground, but needed a power converter, station, and track to run. However they could be set to run in a loop to make things go faster (twice the track half the time).