This website: http://www.mollis.no/tjeremile/TjereStartSide.htm might be of interest. It is a traditional tar pit in Norway, showing the full operation from preparing the pitstead, loading the wood in a special manner, covering, and buning.

This pit is a bit larger than mine.

It should be clarified that the basket framework I have constructued is only going to be the bottom about of the pit itself. The other half will be an earthen-walled formation on top of the frame.