[muawiyah]

Oil shale is a tad difficult to work with. There's a river of it about 10 miles wide extending from the Michigan border to the Ohio in Indiana.

It's also highly radioactive. (This is the stuff they used to make the now banned "black boards" out of).

That particular deposit could supply all our energy needs for many centuries.

[elli1]

It's also highly radioactive. (This is the stuff they used to make the now banned "black boards" out of).

Think you are confusing slate (the original blackboard) with transite blackboards. The original Transite was asbestos reinforced cement board and was used in place of slate for a lot of applications such as blackboards, lab countertops, roofing tiles, etc. There were a lot of other applications for Transite (fire-proofing, electrical insulation...) Ended up on the poopy list because of asbestos. (Transite 1000 is a non-asbestos product.)

Transite 1000

[dangus]

>> It's also highly radioactive. (This is the stuff they used to make the now banned "black boards" out of). <<


???!!!!
I thought they were just less convenient than the marker-boards ("White boards")

Are you saying they disappeared because they were banned for being RADIOACTIVE???