The Mining Festival in Rune Factory 2 occurs in Winter and you have not married yet or if all Eligible Girls are not at full 10,10 Heart Levels in the first year, speaking to every one on the day of the Festival is an opportunity to increase levels.
It is an interesting contest in a way. The object of the contest is to mine a specific gem and present it to Herman in the quickest amount of time. Herman will tell you that you can mine from any Cave but the gem he specifies will be found only in the Cave/Caves where you ordinarily would find it.
What you need to remember is that the result whenever you smash a rock in a Cave always is random. In the first year, the designated Gem is a Ruby, found only on Blessia Island. If you go to Blessia Island without saving your game first and smash every rock on the Island, you may be forced to leave without a single Ruby! I did it as a test to see if the day of the Mining Contest would produce more gems than usual. I never mined at Blessia Island before without obtaining at least one or two Rubies EXCEPT on the day of the Mining Contest. Of course, that was a random result. If I had saved my game at the Port before entering, I could have reloaded to mine again...
In point of fact, it was only a test so I didn't save the result. I was interested to see if Herman would accept a Ruby taken from my Cabinet instead, so the next time I played through the Contest, I rushed home and fetched a Ruby from storage, then gave it to him. He was astonished by my speed and pronounced me the winner!
Incidentally, when I did it 'honestly' and smashed every rock on Blessia Island after defeating the pesky monsters who try to interfere, I brought back six Rubies, gave one to Herman and still won the Contest. He told me
'Ohhhh! What an umbelievably fast time! To think that I'd live to see such unprecedented speed!'
The prize for winning is an 'Invinciroid'.
What I found more interesting even than this, however, was the fact that Yue competed in this Contest. She really is a hardy, fearless adventurer in her own right. I did not marry her in this test game simply because she has Requests to make in the 2nd Generation and I wanted to keep it as close to the 'average' game as possible...
When you speak to the participants in the Mining Contest, Yue will teach Roy another 'foreign phrase' which he rather rudely calls a 'funny phrase'. The actual phrase she will teach him is random and there is more than one dialogue connected to this. I am very sorry I didn't document all possible dialogues, but I really must move on... In any event, I did document the most interesting one, which involves a potential romance between Cammy and Roy as well as one other. If there's a third, I'll leave it for discovery in my next game! I don't want to wring every surprise from Rune Factory 2 in my first game.
In one result, Yue teaches Roy the word 'Maido' which she declares is a 'way for merchants to say goodbye when a customer has made a purchase.' She then suggests he ask his Mum for a sweet and when she gives it to him, say 'Maido'. Roy suspiciously asks: 'Why would I do that?'
(In my own rather hasty research, I discovered that:
'Maido!' is short for 'Maido, osewa ni narimasu,' a phrase many merchants and buisinessmen formerly used in Osaka to greet one another.)
In another result, Yue teaches him the phrase: 'Suki ya nen.' She declares: 'You should say this when you're confessing your true feelings to that special some one', then suggests that Roy 'run over to Cammy and pour your heart out!)
(Again, in my research, I discovered that 'Suki ya nen' is the equivalent in Osaka of 'Suki desu' in standard Japanese, which means 'I like him/her/it.' These phrases suggest that Yue is a merchant from Osaka or the Harvest Moon equivalent of Osaka!)
Once more, these little details are part of the delight of playing any Harvest Moon game. Like the random occurrence at the New Year Festival in Island of Happiness, when your character actually chokes on a Rice Cake, it is only by experiencing the same event/Festival again and again that a player will discover the wealth of detail that has been created in these games.
I will marry both Yue and Mana when I play games on my own permanent cartridge. At this point in time, however, I chose a different wife for the game that ultimately will be erased... Guess whom I chose...
By the way, with respect to mining, there will be a point when Herman will give you all sorts of spurious advice, such as an old wives' tale to the effect that drinking milk before you mine will increase the number of gems found. One would expect that players will not be take any of it seriously...