In the final area of the Diamond Mine, DUCK DOWN when the mine cart gets close to the ceiling, and JUMP when there is a rock in your way (there are three of each). You should jump *before* you reach the sign that says Jump.
Go to youtube.com and search for it and they will show you a video! how easy.
The mine cart ride is the final challenge at the Diamond Mine on Nabooti Island. The only thing you need to do is duck down when you are close to the ceiling, and jump up to avoid the boards immediately after that (repeats three times). (see related question)
On the mine carts you duck jump duck jump duck jump then stay
In the diamond mine is the White Jewel.
you get a gem in the mine
There is no oil can on Nabooti Island. For the Diamond Mine, see the related question below.
the white jewel.
At the bottom of Africa
at the botttom of the map of Africa
Dodge the mine carts, go down the elevator, blast the rock and the wall, ride the mine cart, and get the White Jewel from the diamond pile. (see related question)
All you need to do in the Diamond Mine cart is to duck down into the cart when the ceiling gets close, then jump over the wooden barriers (it says "Jump" a little late).
In the diamond mine after you go into the mine where there is a wall blocking t he way. ;)