Timna (Timnah)
תִּמְנָה
"Timnah" is the name of a place in the land of the tribe of Dan.
"And the border compassed from Baalah westward unto mount Seir, and passed along unto the side of mount Jearim, which is Chesalon, on the north side, and went down to Beth-shemesh, and passed on to Timnah." Jushua 15, 10.

Timna is misspeplt
Timna ends with "ain", not "hei".
Example:
http://he.wikipedia.org/wiki/%D7%91%D7%A7%D7%A2%D7%AA_%D7%AA%D7%9E%D7%A0%D7%A2
Hence, English spelling can't be "Timnah".