The metal key is gained during the Tourist Trap quest. It is obtained by killing the Mercenary Captain outside the gate during the quest. It allows access to the main gate of the Desert Mining Camp.
This key can be placed on the Steel key ring. It can be used to access a mine with mithril and adamant rocks.
If lost another key can be retrieved by killing the Mercenary Captain again. After a certain point of the quest it can also be obtained by searching the table with the water bowl in the camp.
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