Tin Bar

A Tin Bar is a solid bar of tin metal crafted by Miners. It is used in the creation of Bronze Bars.

Source
This item is crafted by Miners with a skill level of 65. Smelting Tin stops giving skillups to Mining at 75.

The miner must be at a forge to smelt the ore into bars.

Tin Bar as an Ingredient
The only known use for Tin Bars as an ingredient is in the production of Bronze Bars.

Tin Bar as a quest objective
During the Opening of the Gates of Ahn'Qiraj event Tin bars were required for the following quests as part of the war effort: