Thanks for the chapter!
It's kind of late to be thinking of getting a successor after 1000 years have passed since got advice from his father. Either he's human + long lived race or he's acquired something or achieved enlightenment that severely slows down or halts the ageing process. Otherwise he'd be a wrinkled 1000+ year old man. Although doesn't seem like he feels rushed about it. As for beam mining that's only useful for quickly making a tunnel unless he the beam automatically or can be set to blast only common dirt or rock. Otherwise the beam would destroy the ores he's mining. Also, miners usually add braces every few steps to help prevent cave-ins due to tunneling weakening or shifting the rock overhead and making it unstable. Just because the tunnel doesn't collapse right away doesn't mean it isn't slowly shifting until it collapses an hour later.
In any case, so we've got the sheltered princess and the miner who's been out of touch with society for over a century. I see a lot of humorous misunderstandings in the future.