When you work long enough and hard enough, the wear on your body chemistry affects your mental/emotional state. You start making mistakes, not because you become less able to swing the pickaxe, but because your attentiveness decreases. Doing real, physical work, like mining or construction, does have a mental wear to it. And there is more to mining than simply swinging a pickaxe. As you tire, your perception is altered, your judgement is impaired, and your thinking is slowed.
By midafternoon, with the hundred-degree sun beating down on you, and everything covered in dirt and dust, every breath becomes a heated effort. You stumble along with your mind numbed, relying on the years of practice and reflex to keep your body going to the end of the day, repetitive motion becomes the rhythm of your life, and your thoughts contract to within the circle of your own stumbling steps. This is when mistakes happen; this is when people get hurt or killed. Not because they collapse (although that does happen), but because the mind no longer works as it should.
That's absolutely right. (Well, as long as your 100 degrees are not my 100 degrees...)
Now, to stay on the topic of game mechanics: Mental stamina doesn't really make sense for mining, as it is; but it has a purpose. What can be done to give it more sense while keeping its purpose? Yes, I do have trouble figuring this purpose myself. Frankly, the mining player is bored much faster than the character could ever be, so chatting with the neighbours should happen anyway. If someone doesn't want to chat, he can't be forced. And mining is not boring anyway; not when you like it; like any other activity. To be a miner, you shouldn't be bored by mining. And a (stereotypical) dwarf is never bored with mining.
Also, currently, you have to stop mining for a few seconds until you have enough will back. Lots of tiny breaks are odd. Dig 30 seconds, rest 15 s, dig 30 s, and so on. When you are tired, either physically or mentally, you take a proper break before starting again. And it doesn't have much to do with will. Dig 1 hour, rest 10 minutes. But the time scale in PS is not our time scale...
So now with the suggestions:
- One (passable) way is, when you reach 0, you wouldn't be able to dig until the progress bar reaches a much higher value. I need only 12-13% myself; maybe 50% or even 100% would be better.
- Another way is a much slower mental stamina drain and recovery. This considers that one has to get physically tired before his spirit would give up. As someone mentioned in an earlier post, it's not necessarily true. Taste for an activity is paramount, not the hardship of that activity.
- My choice (so far) would go more like this: Mental stamina's purpose is concentration, and its loss doesn't stop you from mining, but lowers your efficiency. In which way can again be debated, but at the end of the day it means less ore in the bag. This would also play well with the suggestions on dangerous mining (in another thread).
- Maybe mental stamina doesn't represent boredom, but morale. If so, make chatting and RPing keep mental stamina higher. Too hard to implement in my opinion, but one of you guys may find a way... (I really don't understand why none of these dwarves whistle while digging; I've got a shortcut for that.)
- Get rid of mental stamina altogether. After all, that's what the mining skill is for. Or combine the two (if it's not how it's done already). Rookies try a job, find out they don't have the spirit for it, and quit for another career path.
- Lower the gray bar not because you dig for a long time, but whenever you don't dig out anything of value. That's consistent with both concentration and morale. Raise the value when you find something, but veeery slowly otherwise.
- Allow group mining (akin to group fighting). The gray bar would stay higher for those miners. Before elaborating, I'd first ask if it is technically feasible at all.
- Give ways to get mental stamina back. No potions needed: food and beverages would do, for example. Plenty of space for elaborations and implications there.
This post is from a former miner. I don't aim at realism, as it cannot be achieved anyway. Believability does it. I see the use of several stats and skills as adding variety to a profession; this is why I think mental stamina is a plus to the game. I wouldn't mind having more percentage bars going down while I dig, as long as the big red message when 0% is reach makes sense

, which is what this thread is about originally. (Warning: You do need to sharpen your pick, rehydrate yourself, remove the dust from your eyes, brush your teeth and run behind a rock to pull down your pants. Now!)
Maybe this mining mental issue wouldn't be if it was applied to all professions. Isn't forge work boring / demoralising / repetitive / exhausting? What happens to fighters after the adrenalin rush? Isn't spellcasting a bit tiresome, physically? (Opinions from real life professional spellcasters would be really appreciated here.)