Lol, exploding sackboys is funny, funny stuff.
Which crevasse? If it's the first one, push the platform until it makes a ramp (you should see where it kinda locks in to the rock ledge) and then pull the bomb down it, slowly. After you get it in the cart, pull it into the other cart, slowly. Push the cart over the second crevasse, pull the lever, step on the button and BOOM. Going slow is the key.
Before I buy this game I want to know if it is possible to build an ice rink type level?
Add me on whatever name you're using these days and I'll play it with you