Orc/Goblinoid Resources

[Eikonos]

i wasn't thinking tunnel warfare so much as survival if the mine collapsed

Perhaps a force field that absorbs damage from falling rocks and debris, giving a reactive (immediate action) Damage Resistance for a limited duration ??

It could give the wearer ability to survive without food and water, as the Ring of Sustenance.

It could emit vibrations in a wide area, that would allow wearer to locate empty spaces of considerable size, eg. caves, tunnels, to help him navigate after a cave-in.