do you have any info re. charcoal burning in an oil drum,
There's the upright way linked to above, and there's the "lying on it's side way", which is how I do it. Take a 55 gal oil drum and cut a slot right down the side from top to bottom. Then cut another parallel slot 9" from that. Now cut across the two ends so you end up with a huge letterbox shape.
Now either dig a shallow trench oil drum length, or have a few bags of sand handy.
Lay the drum on it's side, slot uppermost and fill with wood (around 2" - 3" diameter pieces work best). Set them on fire and get a good blaze going. Make sure the whole drum is well packed with wood.
When it's good and blazing, roll it over so the slot is on the bottom.
If you dug a shallow trench, make sure it rolls into the trench, slot down, and use the ezcavated soil to pack around the sides to seal the slot from any air.
If you are using sand, pack the sand round the edges to keep any air out too.
Then let it burn and get cold. When it's cold, roll it over and remove the charcoal. There will be some half consumed bits in there too (they are known as "brownings" in the trade) and you keep them to start the next burn.
The advantage of this method over the upright method is you don't have to faff around making a tight fitting lid.
Eric