Crossword Puzzle Remain durable

Clue: Remain durable

". . . who shall remain ___" (NAMELESS with 8 letters)
Record for an individual athlete at a single Olympic Games that remained unbroken until 2008 (SEVENGOLDMEDALS with 15 letters)
Ancient remains (RUIN with 4 letters)
Of a durable wood (OAKEN with 5 letters)
Pencil remainder (STUB with 4 letters)
Steak remains (GRISTLE with 7 letters)
Durable one (e.g. IRONMAN with 7 letters)
Source of durable wood? (VIAGRA with 6 letters)
Some remains (ASHES with 5 letters)
Remains of a felling (TREESTUMP with 9 letters)