Mark and I dug up a line with the Kubota BX 25D. Great job Dave. I didn’t get a backhoe with mine, if you need one it sure is great, thanks for posting!  You guys were spot on at locating the problem. You had the right equipment and repaired the problem in short order. Most importantly you knew were the gas line was located. I'm sure the home owner was pleased.  Maybe some loctite on those threads. I removed a 20-plus year old 4" rubber sleeve on a waste line and the screws were hand-loose. Furthermore I installed a 2" rubber sleeve on a drain temporary and when I went to remove it about two weeks later it the screw/nut could be turned by hand as well.  Neither sleeve was leaking, but still.  Nice work good digging .The only thing that i would add is for saftey sake Your helper should not be that close tothe machine while you are digging because if you made a wrong move and it doesn't matter how good you are we all do it sometimes you could kill or injure him but other than that you did a great job.  There is a gas line in close proximity to your dig. Also, sewage [methane and hydrogen sulfide] is flammable and highly explosive. Apparently, you are very near it.  The man helping locate the sewage line line is down very close to its location with a lit cigarette in his hand.  BOOM BOOM!  Between the bucket, the gases and the cigarette he could have lost his head.  Glad he didn't.