Cozzle is at 42,18. He drops the key that unlocks the chest in a small house at 43,20.

Kill Foreman Cozzle ( https://classicdb.ch/?npc=4723 ) to get Cozzle's Key and use it to unlock the chest in a small house (next to the lumber mill) at 43,20

Lake Nezferiti is at the northern end of the zone. Booty Bay is in the south. The run in between is scary and long, so if you are alliance, at least, the best option is likely to fly to Darkshire and run form there.

The mining operation is on the east side of the lake. The easiest way to find it is to exit the road just _before_ the bridge across the first river, and follow the river shore east to the mining area.

Cozzle is on the second level of what looks like an oil platform just off the east coast of the lake, in the control building. Fight your way up, kill the two guards outside the building (Cozzle won't add as long as you stay back from the building entrance. Med up, then kill Cozzle. He is a level 38 mob.

NOTE: At the time of this writing there is a known bug which prevents druids from looting his key. We killed him four times and I (NE Druid) never saw the key. My girlfriend (NE Hunter) saw it each time. Blizzard has confirmed this is an issue.

Once you have the key, Cozzle's house is back on shore, further south, past the saw mill. Open the chest you find there and loot the blueprints.

He's in the cabin at the top of the oil tower.

He'll drop the key which opens the chest in the home.