episode featuring 16 Tons sung by bass...

What's the episode that features a guy (hands resting upon a shovel) with a nice, round bass voice singing the Ford song 16 Tons in a coal mine setting?



When the song ends Welk makes a remark to the effect of, "Wow, who new that miners had such low voices?".

The only other thing I know about the episode is that its a colour one.