My folks had a natural gas line leak killing the grass in a spot just off the side entrance. The gas company dug it up, then the repair guy cleaned off the plastic wrapping the pipe. He then took a torch to the pipe upstream of the leak, heating the pipe to red hot. Then he used a pair of pliers and crimped the pipe shut, stopping the gas flow. Leaky section of pipe cut out, new section welded in. Heat the crimped area red hot again, and finagle it with pliers to open it back up. Tested for leaks (bubble solution) and finding none, reapply protective pipe wrap and fill in the hole. Grass grows great now. Oh, this was in the drop between main line and meter, at least 50ft from the main line, and at least 75ft from the meter.
sdb