The driller shouldn't be the only one who knows how to run the drill rig. One winter's day I saw a driller tangled in a line being hoisted towards the crown shieve. Most all of the helpers ran, not knowing what to do, while one helper, not knowing the controls, possibly saved the driller's life by pulling the spark plug wires off the engine. In another case, I watched a drilling business almost go out of business because the owner was in a bad car accident and proposals were no longer written and no one knew which jobs were coming up next.
We would be doing ourselves and our fellow employees a favor if we shared our knowledge of our jobs with each other. If we can trust others to take over our job, it frees us to be away from the job and explore other opportunities like vacations or even retirement. Empowered employees receive a sense of pride by taking over the steering wheel and learning new skills. Most employees need to feel like they are growing in their jobs or challenged with new opportunities.
Mentoring is when older, more experienced people take younger apprentices under their wings and show them the ropes or things only seasoned veterans know from years of experience. A mentor can teach things that can't be learned in books or college courses. Mentoring is not easy for the teacher or the student. Mentoring takes time and patience on both parts. There are many excuses not to mentor, but a commitment to stick with it is needed to keep the mentoring process going.
Also learn to delegate tasks that only you normally do yourself. Try to go on vacation without calling in every five minutes. You might actually find the business does better without you! That's a good thing.