2002, John Perry, Quick and the Dead: Stawell and Its Race Through Time, page 118:
While Millard did not shift from log cabin to White House, he did transport himself from beyond the Black Stump to strike it rich at Stawell.
2004, Leon F. Williams, Rubies of Mogok, Trafford, page 104:
“Just don't go gettin' serious,” Frank warned. “We don't want any trouble. We're gonna be beyond the black stump out there, not at the bloody Lennox Hotel.”
2004, John Leonard Spencer, Waving Goodbye to a Thousand Flies, page 241:
Kimberly, his eldest daughter who we love dearly, is very pregnant with our great grand daughter, the father of whom I have never met and who has shot through to the outback far beyond the black stump.
Origin and development contested; possibly from the use of fire-blackened tree-stumps when providing directions to people, or from a particular black stump: see Wikipedia. Attested since the 20th century, and possibly developed in the 19th century.