I have had an unopened tub of high ratio shortening for about 2 years - would it still be good? It has been stored in a very cool place - my basement.

Can someone tell me?

It should have a date on it .. if not - 2 years is usually the storage life ..

whats the shelf life if its been opened?

Stored correctly, it is the date that's on the container: or 2 years from the packaging date.

With anything that is being used in the kitchen, cross contamination is the cause of "long life" materials going "off" ... Dropping crumbs, splashing liquids and sloppy food-safety all contribute to contamination.

Use clean items to remove the amount you want: don't "double-dip" spoons/spatulas etc: make sure it is air-tight, out of direct sunlight, cool/dark storage ... etc