Miner Forty-Niner was the disguise of Hank.
He was a Caucasian male, with a large grey beard along with a large grey mustache. He wore a brown cowboy hat, which covered the top half of his face. Only his nose was left visible. His great height actually came from Hank wearing stilts. He wore brown pants and a long-sleeve blue top, over which he wore an open black waistcoat.
For the most part, he remained expressionless throughout chasing the gang. At times he grunted, as well as, letting out moans to scare people. He seemed genuinely shocked when he was fooled into thinking he was in the path of an incoming train, the surprise in his face, lifting his hat and revealing his eyes.
He attempted to grab Scooby-Doo and the gang at some points, but that's the extreme of his actions mostly.
Scooby-Doo, Where Are You!
Hank used the disguise to scare off employers and guests of the Gold City Guest Ranch, so he could buy the land cheap.